diff options
author | root <root@nuedel.(none)> | 2011-09-26 11:23:06 +0200 |
---|---|---|
committer | Harald Welte <laforge@gnumonks.org> | 2011-10-10 08:38:58 +0200 |
commit | af48bed556079313074d8a2ea132fd689af8a100 (patch) | |
tree | c027cc6e8f93257ddcda20c4f794d83760e443d0 /src | |
parent | 8a996b4844f8f89c16ce5062c74942d57f6f73b4 (diff) |
Split of LAPDm into a core part and a GSM specific part
Instead of mixing together the GSM layer 1 interface and RSL interface
with the implementation of LAPD, the core function of LAPD is now
extracted from LAPDm. The core implementation is now in lapd_core.c
and lapd_core.h respectively.
The lapd_core.c implements exactly one datalink instance for one SAP.
The surrounding implementation "lapdm.c" codes/decodes the layer 2
headers and handles multiplexing and datalink instances, as well as
translates primitives from/to RSL layer.
lapd_core.c can now be used for other LAPD implementations. (ISDN/ABIS)
Diffstat (limited to 'src')
-rw-r--r-- | src/gsm/Makefile.am | 2 | ||||
-rw-r--r-- | src/gsm/lapd_core.c | 2128 | ||||
-rw-r--r-- | src/gsm/lapdm.c | 1947 |
3 files changed, 2456 insertions, 1621 deletions
diff --git a/src/gsm/Makefile.am b/src/gsm/Makefile.am index f5e46769..c0f72b3f 100644 --- a/src/gsm/Makefile.am +++ b/src/gsm/Makefile.am @@ -10,6 +10,6 @@ lib_LTLIBRARIES = libosmogsm.la libosmogsm_la_SOURCES = a5.c rxlev_stat.c tlv_parser.c comp128.c gsm_utils.c \ rsl.c gsm48.c gsm48_ie.c gsm0808.c sysinfo.c \ gprs_cipher_core.c gsm0480.c abis_nm.c gsm0502.c \ - lapdm.c + lapd_core.c lapdm.c libosmogsm_la_LDFLAGS = -version-info $(LIBVERSION) libosmogsm_la_LIBADD = $(top_builddir)/src/libosmocore.la diff --git a/src/gsm/lapd_core.c b/src/gsm/lapd_core.c new file mode 100644 index 00000000..f7408e54 --- /dev/null +++ b/src/gsm/lapd_core.c @@ -0,0 +1,2128 @@ +/* LAPD core implementation */ + +/* (C) 2010-2011 by Harald Welte <laforge@gnumonks.org> + * (C) 2010-2011 by Andreas Eversberg <jolly@eversberg.eu> + * + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + * + */ + +/*! \addtogroup lapd + * @{ + */ + +/*! \file lapd.c */ + +/*! + * Notes on Buffering: rcv_buffer, tx_queue, tx_hist, send_buffer, send_queue + * + * RX data is stored in the rcv_buffer (pointer). If the message is complete, it + * is removed from rcv_buffer pointer and forwarded to L3. If the RX data is + * received while there is an incomplete rcv_buffer, it is appended to it. + * + * TX data is stored in the send_queue first. When transmitting a frame, + * the first message in the send_queue is moved to the send_buffer. There it + * resides until all fragments are acknowledged. Fragments to be sent by I + * frames are stored in the tx_hist buffer for resend, if required. Also the + * current fragment is copied into the tx_queue. There it resides until it is + * forwarded to layer 1. + * + * In case we have SAPI 0, we only have a window size of 1, so the unack- + * nowledged message resides always in the send_buffer. In case of a suspend, + * it can be written back to the first position of the send_queue. + * + * The layer 1 normally sends a PH-READY-TO-SEND. But because we use + * asynchronous transfer between layer 1 and layer 2 (serial link), we must + * send a frame before layer 1 reaches the right timeslot to send it. So we + * move the tx_queue to layer 1 when there is not already a pending frame, and + * wait until acknowledge after the frame has been sent. If we receive an + * acknowledge, we can send the next frame from the buffer, if any. + * + * The moving of tx_queue to layer 1 may also trigger T200, if desired. Also it + * will trigger next I frame, if possible. + * + * T203 is optional. It will be stated when entering MF EST state. It will also + * be started when I or S frame is received in that state . It will be + * restarted in the lapd_acknowledge() function, in case outstanding frames + * will not trigger T200. It will be stoped, when T200 is started in MF EST + * state. It will also be stoped when leaving MF EST state. + * + */ + +/* Enable this to test content resolution on network side: + * - The first SABM is received, UA is dropped. + * - The phone repeats SABM, but it's content is wrong, so it is ignored + * - The phone repeats SABM again, content is right, so UA is sent. + */ +//#define TEST_CONTENT_RESOLUTION_NETWORK + +#include <stdio.h> +#include <stdint.h> +#include <string.h> +#include <errno.h> +#include <arpa/inet.h> + +#include <osmocom/core/logging.h> +#include <osmocom/core/timer.h> +#include <osmocom/core/msgb.h> +#include <osmocom/core/utils.h> +#include <osmocom/core/talloc.h> +#include <osmocom/gsm/lapd_core.h> + +/* TS 04.06 Table 4 / Section 3.8.1 */ +#define LAPD_U_SABM 0x7 +#define LAPD_U_SABME 0xf +#define LAPD_U_DM 0x3 +#define LAPD_U_UI 0x0 +#define LAPD_U_DISC 0x8 +#define LAPD_U_UA 0xC +#define LAPD_U_FRMR 0x11 + +#define LAPD_S_RR 0x0 +#define LAPD_S_RNR 0x1 +#define LAPD_S_REJ 0x2 + +#define CR_USER2NET_CMD 0 +#define CR_USER2NET_RESP 1 +#define CR_NET2USER_CMD 1 +#define CR_NET2USER_RESP 0 + +#define LAPD_HEADROOM 56 + +#define SBIT(a) (1 << a) +#define ALL_STATES 0xffffffff + +/* UTILITY FUNCTIONS */ + +struct msgb *lapd_msgb_alloc(int length, const char *name) +{ + /* adding space for padding, FIXME: add as an option */ + if (length < 21) + length = 21; + return msgb_alloc_headroom(length + LAPD_HEADROOM, LAPD_HEADROOM, name); +} + +static inline uint8_t do_mod(uint8_t x, uint8_t m) +{ + return x & (m - 1); +} + +static inline uint8_t inc_mod(uint8_t x, uint8_t m) +{ + return (x + 1) & (m - 1); +} + +static inline uint8_t add_mod(uint8_t x, uint8_t y, uint8_t m) +{ + return (x + y) & (m - 1); +} + +static inline uint8_t sub_mod(uint8_t x, uint8_t y, uint8_t m) +{ + return (x - y) & (m - 1); /* handle negative results correctly */ +} + +static void lapd_dl_flush_send(struct lapd_datalink *dl) +{ + struct msgb *msg; + + /* Flush send-queue */ + while ((msg = msgb_dequeue(&dl->send_queue))) + msgb_free(msg); + + /* Clear send-buffer */ + if (dl->send_buffer) { + msgb_free(dl->send_buffer); + dl->send_buffer = NULL; + } +} + +static void lapd_dl_flush_hist(struct lapd_datalink *dl) +{ + unsigned int i; + + for (i = 0; i < dl->range_hist; i++) { + if (dl->tx_hist[i].msg) { + msgb_free(dl->tx_hist[i].msg); + dl->tx_hist[i].msg = NULL; + } + } +} + +static void lapd_dl_flush_tx(struct lapd_datalink *dl) +{ + struct msgb *msg; + + while ((msg = msgb_dequeue(&dl->tx_queue))) + msgb_free(msg); + lapd_dl_flush_hist(dl); +} + +/* Figure B.2/Q.921 */ +const char *lapd_state_names[] = { + "LAPD_STATE_NULL", + "LAPD_STATE_TEI_UNASS", + "LAPD_STATE_ASS_TEI_WAIT", + "LAPD_STATE_EST_TEI_WAIT", + "LAPD_STATE_IDLE", + "LAPD_STATE_SABM_SENT", + "LAPD_STATE_DISC_SENT", + "LAPD_STATE_MF_EST", + "LAPD_STATE_TIMER_RECOV", + +}; + +static void lapd_dl_newstate(struct lapd_datalink *dl, uint32_t state) +{ + LOGP(DLLAPD, LOGL_INFO, "new state %s -> %s\n", + lapd_state_names[dl->state], lapd_state_names[state]); + + if (state != LAPD_STATE_MF_EST && dl->state == LAPD_STATE_MF_EST) { + /* stop T203 on leaving MF EST state, if running */ + if (osmo_timer_pending(&dl->t203)) { + LOGP(DLLAPD, LOGL_INFO, "stop T203\n"); + osmo_timer_del(&dl->t203); + } + /* remove content res. (network side) on leaving MF EST state */ + if (dl->cont_res) { + msgb_free(dl->cont_res); + dl->cont_res = NULL; + } + } + + /* start T203 on entering MF EST state, if enabled */ + if ((dl->t203_sec || dl->t203_usec) + && state == LAPD_STATE_MF_EST && dl->state != LAPD_STATE_MF_EST) { + LOGP(DLLAPD, LOGL_INFO, "start T203\n"); + osmo_timer_schedule(&dl->t203, dl->t203_sec, dl->t203_usec); + } + + dl->state = state; +} + +static void lapd_t200_cb(void *data); +static void lapd_t203_cb(void *data); +static int lapd_send_i(struct lapd_msg_ctx *lctx, int line); +static int lapd_est_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx); + +static void *tall_lapd_ctx = NULL; + +/* init datalink instance and allocate history */ +void lapd_dl_init(struct lapd_datalink *dl, uint8_t k, uint8_t v_range, + int maxf) +{ + int m; + + memset(dl, 0, sizeof(*dl)); + INIT_LLIST_HEAD(&dl->send_queue); + INIT_LLIST_HEAD(&dl->tx_queue); + dl->reestablish = 1; + dl->n200_est_rel = 3; + dl->n200 = 3; + dl->t200_sec = 1; + dl->t200_usec = 0; + dl->t200.data = dl; + dl->t200.cb = &lapd_t200_cb; + dl->t203_sec = 10; + dl->t203_usec = 0; + dl->t203.data = dl; + dl->t203.cb = &lapd_t203_cb; + dl->maxf = maxf; + if (k > v_range - 1) + k = v_range - 1; + dl->k = k; + dl->v_range = v_range; + + /* Calculate modulo for history array: + * - The history range must be at least k+1. + * - The history range must be 2^x, where x is as low as possible. + */ + k++; + for (m = 0x80; m; m >>= 1) { + if ((m & k)) { + if (k > m) + m <<= 1; + dl->range_hist = m; + break; + } + } + + LOGP(DLLAPD, LOGL_INFO, "Init DL layer: sequence range = %d, k = %d, " + "history range = %d\n", dl->v_range, dl->k, dl->range_hist); + + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + + if (!tall_lapd_ctx) + tall_lapd_ctx = talloc_named_const(NULL, 1, "lapd context"); + dl->tx_hist = (struct lapd_history *) talloc_zero_array(tall_lapd_ctx, + struct log_info, dl->range_hist); +} + +/* reset to IDLE state */ +void lapd_dl_reset(struct lapd_datalink *dl) +{ + if (dl->state == LAPD_STATE_IDLE) + return; + LOGP(DLLAPD, LOGL_INFO, "Resetting LAPDm instance\n"); + /* enter idle state (and remove eventual cont_res) */ + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + /* flush buffer */ + lapd_dl_flush_tx(dl); + lapd_dl_flush_send(dl); + /* Discard partly received L3 message */ + if (dl->rcv_buffer) { + msgb_free(dl->rcv_buffer); + dl->rcv_buffer = NULL; + } + /* reset Timers */ + osmo_timer_del(&dl->t200); + osmo_timer_del(&dl->t203); +} + +/* reset and de-allocate history buffer */ +void lapd_dl_exit(struct lapd_datalink *dl) +{ + /* free all ressources except history buffer */ + lapd_dl_reset(dl); + /* free history buffer list */ + talloc_free(dl->tx_hist); +} + +/*! \brief Set the \ref lapdm_mode of a LAPDm entity */ +int lapd_set_mode(struct lapd_datalink *dl, enum lapd_mode mode) +{ + switch (mode) { + case LAPD_MODE_USER: + dl->cr.loc2rem.cmd = CR_USER2NET_CMD; + dl->cr.loc2rem.resp = CR_USER2NET_RESP; + dl->cr.rem2loc.cmd = CR_NET2USER_CMD; + dl->cr.rem2loc.resp = CR_NET2USER_RESP; + break; + case LAPD_MODE_NETWORK: + dl->cr.loc2rem.cmd = CR_NET2USER_CMD; + dl->cr.loc2rem.resp = CR_NET2USER_RESP; + dl->cr.rem2loc.cmd = CR_USER2NET_CMD; + dl->cr.rem2loc.resp = CR_USER2NET_RESP; + break; + default: + return -EINVAL; + } + dl->mode = mode; + + return 0; +} + +/* send DL message with optional msgb */ +static int send_dl_l3(uint8_t prim, uint8_t op, struct lapd_msg_ctx *lctx, + struct msgb *msg) +{ + struct lapd_datalink *dl = lctx->dl; + struct osmo_dlsap_prim dp; + + osmo_prim_init(&dp.oph, 0, prim, op, msg); + return dl->send_dlsap(&dp, lctx); +} + +/* send simple DL message */ +static inline int send_dl_simple(uint8_t prim, uint8_t op, + struct lapd_msg_ctx *lctx) +{ + struct msgb *msg = lapd_msgb_alloc(0, "DUMMY"); + + return send_dl_l3(prim, op, lctx, msg); +} + +/* send MDL-ERROR INDICATION */ +static int mdl_error(uint8_t cause, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + struct osmo_dlsap_prim dp; + + LOGP(DLLAPD, LOGL_NOTICE, "sending MDL-ERROR-IND cause %d\n", + cause); + osmo_prim_init(&dp.oph, 0, PRIM_MDL_ERROR, PRIM_OP_INDICATION, NULL); + dp.u.error_ind.cause = cause; + return dl->send_dlsap(&dp, lctx); +} + +/* send UA response */ +static int lapd_send_ua(struct lapd_msg_ctx *lctx, uint8_t len, uint8_t *data) +{ + struct msgb *msg = lapd_msgb_alloc(len, "LAPD UA"); + struct lapd_msg_ctx nctx; + struct lapd_datalink *dl = lctx->dl; + + memcpy(&nctx, lctx, sizeof(nctx)); + msg->l3h = msgb_put(msg, len); + if (len) + memcpy(msg->l3h, data, len); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.resp; + nctx.format = LAPD_FORM_U; + nctx.s_u = LAPD_U_UA; + /* keep nctx.p_f */ + nctx.length = len; + nctx.more = 0; + + return dl->send_ph_data_req(&nctx, msg); +} + +/* send DM response */ +static int lapd_send_dm(struct lapd_msg_ctx *lctx) +{ + struct msgb *msg = lapd_msgb_alloc(0, "LAPD DM"); + struct lapd_msg_ctx nctx; + struct lapd_datalink *dl = lctx->dl; + + memcpy(&nctx, lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.resp; + nctx.format = LAPD_FORM_U; + nctx.s_u = LAPD_U_DM; + /* keep nctx.p_f */ + nctx.length = 0; + nctx.more = 0; + + return dl->send_ph_data_req(&nctx, msg); +} + +/* send RR response / command */ +static int lapd_send_rr(struct lapd_msg_ctx *lctx, uint8_t f_bit, uint8_t cmd) +{ + struct msgb *msg = lapd_msgb_alloc(0, "LAPD RR"); + struct lapd_msg_ctx nctx; + struct lapd_datalink *dl = lctx->dl; + + memcpy(&nctx, lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = (cmd) ? dl->cr.loc2rem.cmd : dl->cr.loc2rem.resp; + nctx.format = LAPD_FORM_S; + nctx.s_u = LAPD_S_RR; + nctx.p_f = f_bit; + nctx.n_recv = dl->v_recv; + nctx.length = 0; + nctx.more = 0; + + return dl->send_ph_data_req(&nctx, msg); +} + +/* send RNR response / command */ +static int lapd_send_rnr(struct lapd_msg_ctx *lctx, uint8_t f_bit, uint8_t cmd) +{ + struct msgb *msg = lapd_msgb_alloc(0, "LAPD RNR"); + struct lapd_msg_ctx nctx; + struct lapd_datalink *dl = lctx->dl; + + memcpy(&nctx, lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = (cmd) ? dl->cr.loc2rem.cmd : dl->cr.loc2rem.resp; + nctx.format = LAPD_FORM_S; + nctx.s_u = LAPD_S_RNR; + nctx.p_f = f_bit; + nctx.n_recv = dl->v_recv; + nctx.length = 0; + nctx.more = 0; + + return dl->send_ph_data_req(&nctx, msg); +} + +/* send REJ response */ +static int lapd_send_rej(struct lapd_msg_ctx *lctx, uint8_t f_bit) +{ + struct msgb *msg = lapd_msgb_alloc(0, "LAPD REJ"); + struct lapd_msg_ctx nctx; + struct lapd_datalink *dl = lctx->dl; + + memcpy(&nctx, lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.resp; + nctx.format = LAPD_FORM_S; + nctx.s_u = LAPD_S_REJ; + nctx.p_f = f_bit; + nctx.n_recv = dl->v_recv; + nctx.length = 0; + nctx.more = 0; + + return dl->send_ph_data_req(&nctx, msg); +} + +/* resend SABM or DISC message */ +static int lapd_send_resend(struct lapd_datalink *dl) +{ + struct msgb *msg; + uint8_t h = do_mod(dl->v_send, dl->range_hist); + int length = dl->tx_hist[h].msg->len; + struct lapd_msg_ctx nctx; + + /* assemble message */ + memcpy(&nctx, &dl->lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.cmd; + nctx.format = LAPD_FORM_U; + if (dl->state == LAPD_STATE_SABM_SENT) + nctx.s_u = (dl->use_sabme) ? LAPD_U_SABME : LAPD_U_SABM; + else + nctx.s_u = LAPD_U_DISC; + nctx.p_f = 1; + nctx.length = length; + nctx.more = 0; + + /* Resend SABM/DISC from tx_hist */ + msg = lapd_msgb_alloc(length, "LAPD resend"); + msg->l3h = msgb_put(msg, length); + if (length) + memcpy(msg->l3h, dl->tx_hist[h].msg->data, length); + + return dl->send_ph_data_req(&nctx, msg); +} + +/* reestablish link */ +static int lapd_reestablish(struct lapd_datalink *dl) +{ + struct osmo_dlsap_prim dp; + struct msgb *msg; + + msg = lapd_msgb_alloc(0, "DUMMY"); + osmo_prim_init(&dp.oph, 0, PRIM_DL_EST, PRIM_OP_REQUEST, msg); + + return lapd_est_req(&dp, &dl->lctx); +} + +/* Timer callback on T200 expiry */ +static void lapd_t200_cb(void *data) +{ + struct lapd_datalink *dl = data; + + LOGP(DLLAPD, LOGL_INFO, "lapd_t200_cb(%p) state=%d\n", dl, + (int) dl->state); + + switch (dl->state) { + case LAPD_STATE_SABM_SENT: + /* 5.4.1.3 */ + if (dl->retrans_ctr + 1 >= dl->n200_est_rel + 1) { + /* send RELEASE INDICATION to L3 */ + send_dl_simple(PRIM_DL_REL, PRIM_OP_INDICATION, + &dl->lctx); + /* send MDL ERROR INIDCATION to L3 */ + mdl_error(MDL_CAUSE_T200_EXPIRED, &dl->lctx); + /* flush tx and send buffers */ + lapd_dl_flush_tx(dl); + lapd_dl_flush_send(dl); + /* go back to idle state */ + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + /* NOTE: we must not change any other states or buffers + * and queues, since we may reconnect after handover + * failure. the buffered messages is replaced there */ + break; + } + /* retransmit SABM command */ + lapd_send_resend(dl); + /* increment re-transmission counter */ + dl->retrans_ctr++; + /* restart T200 (PH-READY-TO-SEND) */ + osmo_timer_schedule(&dl->t200, dl->t200_sec, dl->t200_usec); + break; + case LAPD_STATE_DISC_SENT: + /* 5.4.4.3 */ + if (dl->retrans_ctr + 1 >= dl->n200_est_rel + 1) { + /* send RELEASE INDICATION to L3 */ + send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, &dl->lctx); + /* send MDL ERROR INIDCATION to L3 */ + mdl_error(MDL_CAUSE_T200_EXPIRED, &dl->lctx); + /* flush tx and send buffers */ + lapd_dl_flush_tx(dl); + lapd_dl_flush_send(dl); + /* go back to idle state */ + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + /* NOTE: we must not change any other states or buffers + * and queues, since we may reconnect after handover + * failure. the buffered messages is replaced there */ + break; + } + /* retransmit DISC command */ + lapd_send_resend(dl); + /* increment re-transmission counter */ + dl->retrans_ctr++; + /* restart T200 (PH-READY-TO-SEND) */ + osmo_timer_schedule(&dl->t200, dl->t200_sec, dl->t200_usec); + break; + case LAPD_STATE_MF_EST: + /* 5.5.7 */ + dl->retrans_ctr = 0; + lapd_dl_newstate(dl, LAPD_STATE_TIMER_RECOV); + /* fall through */ + case LAPD_STATE_TIMER_RECOV: + dl->retrans_ctr++; + if (dl->retrans_ctr < dl->n200) { + uint8_t vs = sub_mod(dl->v_send, 1, dl->v_range); + uint8_t h = do_mod(vs, dl->range_hist); + /* retransmit I frame (V_s-1) with P=1, if any */ + if (dl->tx_hist[h].msg) { + struct msgb *msg; + int length = dl->tx_hist[h].msg->len; + struct lapd_msg_ctx nctx; + + LOGP(DLLAPD, LOGL_INFO, "retransmit last frame" + " V(S)=%d\n", vs); + /* Create I frame (segment) from tx_hist */ + memcpy(&nctx, &dl->lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.cmd; + nctx.format = LAPD_FORM_I; + nctx.p_f = 1; + nctx.n_send = vs; + nctx.n_recv = dl->v_recv; + nctx.length = length; + nctx.more = dl->tx_hist[h].more; + msg = lapd_msgb_alloc(length, "LAPD I resend"); + msg->l3h = msgb_put(msg, length); + memcpy(msg->l3h, dl->tx_hist[h].msg->data, + length); + dl->send_ph_data_req(&nctx, msg); + } else { + /* OR send appropriate supervision frame with P=1 */ + if (!dl->own_busy && !dl->seq_err_cond) { + lapd_send_rr(&dl->lctx, 1, 1); + /* NOTE: In case of sequence error + * condition, the REJ frame has been + * transmitted when entering the + * condition, so it has not be done + * here + */ + } else if (dl->own_busy) { + lapd_send_rnr(&dl->lctx, 1, 1); + } else { + LOGP(DLLAPD, LOGL_INFO, "unhandled, " + "pls. fix\n"); + } + } + /* restart T200 (PH-READY-TO-SEND) */ + osmo_timer_schedule(&dl->t200, dl->t200_sec, + dl->t200_usec); + } else { + /* send MDL ERROR INIDCATION to L3 */ + mdl_error(MDL_CAUSE_T200_EXPIRED, &dl->lctx); + /* reestablish */ + if (!dl->reestablish) + break; + LOGP(DLLAPD, LOGL_NOTICE, "N200 reached, performing " + "reestablishment.\n"); + lapd_reestablish(dl); + } + break; + default: + LOGP(DLLAPD, LOGL_INFO, "T200 expired in unexpected " + "dl->state %d\n", (int) dl->state); + } +} + +/* Timer callback on T203 expiry */ +static void lapd_t203_cb(void *data) +{ + struct lapd_datalink *dl = data; + + LOGP(DLLAPD, LOGL_INFO, "lapd_t203_cb(%p) state=%d\n", dl, + (int) dl->state); + + if (dl->state != LAPD_STATE_MF_EST) { + LOGP(DLLAPD, LOGL_ERROR, "T203 fired outside MF EST state, " + "please fix!\n"); + return; + } + + /* set retransmission counter to 0 */ + dl->retrans_ctr = 0; + /* enter timer recovery state */ + lapd_dl_newstate(dl, LAPD_STATE_TIMER_RECOV); + /* transmit a supervisory command with P bit set to 1 as follows: */ + if (!dl->own_busy) { + LOGP(DLLAPD, LOGL_INFO, "transmit an RR poll command\n"); + /* Send RR with P=1 */ + lapd_send_rr(&dl->lctx, 1, 1); + } else { + LOGP(DLLAPD, LOGL_INFO, "transmit an RNR poll command\n"); + /* Send RNR with P=1 */ + lapd_send_rnr(&dl->lctx, 1, 1); + } + /* start T200 */ + osmo_timer_schedule(&dl->t200, dl->t200_sec, dl->t200_usec); +} + +/* 5.5.3.1: Common function to acknowlege frames up to the given N(R) value */ +static void lapd_acknowledge(struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + uint8_t nr = lctx->n_recv; + int s = 0, rej = 0, t200_reset = 0, t200_start = 0; + int i, h; + + /* supervisory frame ? */ + if (lctx->format == LAPD_FORM_S) + s = 1; + /* REJ frame ? */ + if (s && lctx->s_u == LAPD_S_REJ) + rej = 1; + + /* Flush all transmit buffers of acknowledged frames */ + for (i = dl->v_ack; i != nr; i = inc_mod(i, dl->v_range)) { + h = do_mod(i, dl->range_hist); + if (dl->tx_hist[h].msg) { + msgb_free(dl->tx_hist[h].msg); + dl->tx_hist[h].msg = NULL; + LOGP(DLLAPD, LOGL_INFO, "ack frame %d\n", i); + } + } + + if (dl->state != LAPD_STATE_TIMER_RECOV) { + /* When not in the timer recovery condition, the data + * link layer entity shall reset the timer T200 on + * receipt of a valid I frame with N(R) higher than V(A), + * or an REJ with an N(R) equal to V(A). */ + if ((!rej && nr != dl->v_ack) + || (rej && nr == dl->v_ack)) { + LOGP(DLLAPD, LOGL_INFO, "reset t200\n"); + t200_reset = 1; + osmo_timer_del(&dl->t200); + /* 5.5.3.1 Note 1 + 2 imply timer recovery cond. */ + } + /* 5.7.4: N(R) sequence error + * N(R) is called valid, if and only if + * (N(R)-V(A)) mod 8 <= (V(S)-V(A)) mod 8. + */ + if (sub_mod(nr, dl->v_ack, dl->v_range) + > sub_mod(dl->v_send, dl->v_ack, dl->v_range)) { + LOGP(DLLAPD, LOGL_NOTICE, "N(R) sequence error\n"); + mdl_error(MDL_CAUSE_SEQ_ERR, lctx); + } + } + + /* V(A) shall be set to the value of N(R) */ + dl->v_ack = nr; + + /* If T200 has been reset by the receipt of an I, RR or RNR frame, + * and if there are outstanding I frames, restart T200 */ + if (t200_reset && !rej) { + if (dl->tx_hist[sub_mod(dl->v_send, 1, dl->range_hist)].msg) { + LOGP(DLLAPD, LOGL_INFO, "start T200, due to unacked I " + "frame(s)\n"); + t200_start = 1; + osmo_timer_schedule(&dl->t200, dl->t200_sec, + dl->t200_usec); + } + } + + /* This also does a restart, when I or S frame is received */ + + /* Stop T203, if running */ + if (osmo_timer_pending(&dl->t203)) { + osmo_timer_del(&dl->t203); + LOGP(DLLAPD, LOGL_INFO, "stop T203\n"); + } + /* Start T203, if T200 is not running in MF EST state, if enabled */ + if (!osmo_timer_pending(&dl->t200) + && (dl->t203_sec || dl->t203_usec) + && (dl->state == LAPD_STATE_MF_EST)) { + LOGP(DLLAPD, LOGL_INFO, "start T203\n"); + osmo_timer_schedule(&dl->t203, dl->t203_sec, dl->t203_usec); + } +} + +/* L1 -> L2 */ + +/* Receive a LAPD U (Unnumbered) message from L1 */ +static int lapd_rx_u(struct msgb *msg, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + int length = lctx->length; + int rc; + uint8_t prim, op; + + switch (lctx->s_u) { + case LAPD_U_SABM: + case LAPD_U_SABME: + prim = PRIM_DL_EST; + op = PRIM_OP_INDICATION; + + LOGP(DLLAPD, LOGL_INFO, "SABM(E) received in state %s\n", + lapd_state_names[dl->state]); + /* 5.7.1 */ + dl->seq_err_cond = 0; + /* G.2.2 Wrong value of the C/R bit */ + if (lctx->cr == dl->cr.rem2loc.resp) { + LOGP(DLLAPD, LOGL_NOTICE, "SABM response error\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx); + return -EINVAL; + } + + /* G.4.5 If SABM is received with L>N201 or with M bit + * set, AN MDL-ERROR-INDICATION is sent to MM. + */ + if (lctx->more || length > lctx->n201) { + LOGP(DLLAPD, LOGL_NOTICE, "SABM too large error\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_UFRM_INC_PARAM, lctx); + return -EIO; + } + + switch (dl->state) { + case LAPD_STATE_IDLE: + break; + case LAPD_STATE_MF_EST: + LOGP(DLLAPD, LOGL_INFO, "SABM command, multiple " + "frame established state\n"); + /* If link is lost on the remote side, we start over + * and send DL-ESTABLISH indication again. */ + if (dl->v_send != dl->v_recv) { + LOGP(DLLAPD, LOGL_INFO, "Remote reestablish\n"); + mdl_error(MDL_CAUSE_SABM_MF, lctx); + break; + } + /* Ignore SABM if content differs from first SABM. */ + if (dl->mode == LAPD_MODE_NETWORK && length + && dl->cont_res) { +#ifdef TEST_CONTENT_RESOLUTION_NETWORK + dl->cont_res->data[0] ^= 0x01; +#endif + if (memcmp(dl->cont_res, msg->data, length)) { + LOGP(DLLAPD, LOGL_INFO, "Another SABM " + "with diffrent content - " + "ignoring!\n"); + msgb_free(msg); + return 0; + } + } + /* send UA again */ + lapd_send_ua(lctx, length, msg->l3h); + msgb_free(msg); + return 0; + case LAPD_STATE_DISC_SENT: + /* 5.4.6.2 send DM with F=P */ + lapd_send_dm(lctx); + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + msgb_free(msg); + return send_dl_simple(prim, op, lctx); + default: + /* collision: Send UA, but still wait for rx UA, then + * change to MF_EST state. + */ + /* check for contention resoultion */ + if (dl->tx_hist[0].msg && dl->tx_hist[0].msg->len) { + LOGP(DLLAPD, LOGL_NOTICE, "SABM not allowed " + "during contention resolution\n"); + mdl_error(MDL_CAUSE_SABM_INFO_NOTALL, lctx); + } + lapd_send_ua(lctx, length, msg->l3h); + msgb_free(msg); + return 0; + } + /* save message context for further use */ + memcpy(&dl->lctx, lctx, sizeof(dl->lctx)); +#ifndef TEST_CONTENT_RESOLUTION_NETWORK + /* send UA response */ + lapd_send_ua(lctx, length, msg->l3h); +#endif + /* set Vs, Vr and Va to 0 */ + dl->v_send = dl->v_recv = dl->v_ack = 0; + /* clear tx_hist */ + lapd_dl_flush_hist(dl); + /* enter multiple-frame-established state */ + lapd_dl_newstate(dl, LAPD_STATE_MF_EST); + /* store content resolution data on network side + * Note: cont_res will be removed when changing state again, + * so it must be allocated AFTER lapd_dl_newstate(). */ + if (dl->mode == LAPD_MODE_NETWORK && length) { + dl->cont_res = lapd_msgb_alloc(length, "CONT RES"); + memcpy(msgb_put(dl->cont_res, length), msg->l3h, + length); + LOGP(DLLAPD, LOGL_NOTICE, "Store content res.\n"); + } + /* send notification to L3 */ + if (length == 0) { + /* 5.4.1.2 Normal establishment procedures */ + rc = send_dl_simple(prim, op, lctx); + msgb_free(msg); + } else { + /* 5.4.1.4 Contention resolution establishment */ + rc = send_dl_l3(prim, op, lctx, msg); + } + break; + case LAPD_U_DM: + LOGP(DLLAPD, LOGL_INFO, "DM received in state %s\n", + lapd_state_names[dl->state]); + /* G.2.2 Wrong value of the C/R bit */ + if (lctx->cr == dl->cr.rem2loc.cmd) { + LOGP(DLLAPD, LOGL_NOTICE, "DM command error\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx); + return -EINVAL; + } + if (!lctx->p_f) { + /* 5.4.1.2 DM responses with the F bit set to "0" + * shall be ignored. + */ + msgb_free(msg); + return 0; + } + switch (dl->state) { + case LAPD_STATE_SABM_SENT: + break; + case LAPD_STATE_MF_EST: + if (lctx->p_f) { + LOGP(DLLAPD, LOGL_INFO, "unsolicited DM " + "response\n"); + mdl_error(MDL_CAUSE_UNSOL_DM_RESP, lctx); + } else { + LOGP(DLLAPD, LOGL_INFO, "unsolicited DM " + "response, multiple frame established " + "state\n"); + mdl_error(MDL_CAUSE_UNSOL_DM_RESP_MF, lctx); + /* reestablish */ + if (!dl->reestablish) { + msgb_free(msg); + return 0; + } + LOGP(DLLAPD, LOGL_NOTICE, "Performing " + "reestablishment.\n"); + lapd_reestablish(dl); + } + msgb_free(msg); + return 0; + case LAPD_STATE_TIMER_RECOV: + /* FP = 0 (DM is normal in case PF = 1) */ + if (!lctx->p_f) { + LOGP(DLLAPD, LOGL_INFO, "unsolicited DM " + "response, multiple frame established " + "state\n"); + mdl_error(MDL_CAUSE_UNSOL_DM_RESP_MF, lctx); + msgb_free(msg); + /* reestablish */ + if (!dl->reestablish) + return 0; + LOGP(DLLAPD, LOGL_NOTICE, "Performing " + "reestablishment.\n"); + return lapd_reestablish(dl); + } + break; + case LAPD_STATE_DISC_SENT: + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + /* go to idle state */ + lapd_dl_flush_tx(dl); + lapd_dl_flush_send(dl); + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + rc = send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, lctx); + msgb_free(msg); + return 0; + case LAPD_STATE_IDLE: + /* 5.4.5 all other frame types shall be discarded */ + default: + LOGP(DLLAPD, LOGL_INFO, "unsolicited DM response! " + "(discarding)\n"); + msgb_free(msg); + return 0; + } + /* reset T200 */ + osmo_timer_del(&dl->t200); + /* go to idle state */ + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + rc = send_dl_simple(PRIM_DL_REL, PRIM_OP_INDICATION, lctx); + msgb_free(msg); + break; + case LAPD_U_UI: + LOGP(DLLAPD, LOGL_INFO, "UI received\n"); + /* G.2.2 Wrong value of the C/R bit */ + if (lctx->cr == dl->cr.rem2loc.resp) { + LOGP(DLLAPD, LOGL_NOTICE, "UI indicates response " + "error\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx); + return -EINVAL; + } + + /* G.4.5 If UI is received with L>N201 or with M bit + * set, AN MDL-ERROR-INDICATION is sent to MM. + */ + if (length > lctx->n201 || lctx->more) { + LOGP(DLLAPD, LOGL_NOTICE, "UI too large error " + "(%d > N201(%d) or M=%d)\n", length, + lctx->n201, lctx->more); + msgb_free(msg); + mdl_error(MDL_CAUSE_UFRM_INC_PARAM, lctx); + return -EIO; + } + + /* do some length checks */ + if (length == 0) { + /* 5.3.3 UI frames received with the length indicator + * set to "0" shall be ignored + */ + LOGP(DLLAPD, LOGL_INFO, "length=0 (discarding)\n"); + msgb_free(msg); + return 0; + } + rc = send_dl_l3(PRIM_DL_UNIT_DATA, PRIM_OP_INDICATION, lctx, + msg); + break; + case LAPD_U_DISC: + prim = PRIM_DL_REL; + op = PRIM_OP_INDICATION; + + LOGP(DLLAPD, LOGL_INFO, "DISC received in state %s\n", + lapd_state_names[dl->state]); + /* flush tx and send buffers */ + lapd_dl_flush_tx(dl); + lapd_dl_flush_send(dl); + /* 5.7.1 */ + dl->seq_err_cond = 0; + /* G.2.2 Wrong value of the C/R bit */ + if (lctx->cr == dl->cr.rem2loc.resp) { + LOGP(DLLAPD, LOGL_NOTICE, "DISC response error\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx); + return -EINVAL; + } + if (length > 0 || lctx->more) { + /* G.4.4 If a DISC or DM frame is received with L>0 or + * with the M bit set to "1", an MDL-ERROR-INDICATION + * primitive with cause "U frame with incorrect + * parameters" is sent to the mobile management entity. + */ + LOGP(DLLAPD, LOGL_NOTICE, + "U frame iwth incorrect parameters "); + msgb_free(msg); + mdl_error(MDL_CAUSE_UFRM_INC_PARAM, lctx); + return -EIO; + } + switch (dl->state) { + case LAPD_STATE_IDLE: + LOGP(DLLAPD, LOGL_INFO, "DISC in idle state\n"); + /* send DM with F=P */ + msgb_free(msg); + return lapd_send_dm(lctx); + case LAPD_STATE_SABM_SENT: + LOGP(DLLAPD, LOGL_INFO, "DISC in SABM state\n"); + /* 5.4.6.2 send DM with F=P */ + lapd_send_dm(lctx); + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + /* go to idle state */ + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + msgb_free(msg); + return send_dl_simple(PRIM_DL_REL, PRIM_OP_INDICATION, + lctx); + case LAPD_STATE_MF_EST: + case LAPD_STATE_TIMER_RECOV: + LOGP(DLLAPD, LOGL_INFO, "DISC in est state\n"); + break; + case LAPD_STATE_DISC_SENT: + LOGP(DLLAPD, LOGL_INFO, "DISC in disc state\n"); + prim = PRIM_DL_REL; + op = PRIM_OP_CONFIRM; + break; + default: + lapd_send_ua(lctx, length, msg->l3h); + msgb_free(msg); + return 0; + } + /* send UA response */ + lapd_send_ua(lctx, length, msg->l3h); + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + /* enter idle state, keep tx-buffer with UA response */ + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + /* send notification to L3 */ + rc = send_dl_simple(prim, op, lctx); + msgb_free(msg); + break; + case LAPD_U_UA: + LOGP(DLLAPD, LOGL_INFO, "UA received in state %s\n", + lapd_state_names[dl->state]); + /* G.2.2 Wrong value of the C/R bit */ + if (lctx->cr == dl->cr.rem2loc.cmd) { + LOGP(DLLAPD, LOGL_NOTICE, "UA indicates command " + "error\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx); + return -EINVAL; + } + + /* G.4.5 If UA is received with L>N201 or with M bit + * set, AN MDL-ERROR-INDICATION is sent to MM. + */ + if (lctx->more || length > lctx->n201) { + LOGP(DLLAPD, LOGL_NOTICE, "UA too large error\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_UFRM_INC_PARAM, lctx); + return -EIO; + } + + if (!lctx->p_f) { + /* 5.4.1.2 A UA response with the F bit set to "0" + * shall be ignored. + */ + LOGP(DLLAPD, LOGL_INFO, "F=0 (discarding)\n"); + msgb_free(msg); + return 0; + } + switch (dl->state) { + case LAPD_STATE_SABM_SENT: + break; + case LAPD_STATE_MF_EST: + case LAPD_STATE_TIMER_RECOV: + LOGP(DLLAPD, LOGL_INFO, "unsolicited UA response! " + "(discarding)\n"); + mdl_error(MDL_CAUSE_UNSOL_UA_RESP, lctx); + msgb_free(msg); + return 0; + case LAPD_STATE_DISC_SENT: + LOGP(DLLAPD, LOGL_INFO, "UA in disconnect state\n"); + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + /* go to idle state */ + lapd_dl_flush_tx(dl); + lapd_dl_flush_send(dl); + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + rc = send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, lctx); + msgb_free(msg); + return 0; + case LAPD_STATE_IDLE: + /* 5.4.5 all other frame types shall be discarded */ + default: + LOGP(DLLAPD, LOGL_INFO, "unsolicited UA response! " + "(discarding)\n"); + msgb_free(msg); + return 0; + } + LOGP(DLLAPD, LOGL_INFO, "UA in SABM state\n"); + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + /* compare UA with SABME if contention resolution is applied */ + if (dl->tx_hist[0].msg->len) { + if (length != (dl->tx_hist[0].msg->len) + || !!memcmp(dl->tx_hist[0].msg->data, msg->l3h, + length)) { + LOGP(DLLAPD, LOGL_INFO, "**** UA response " + "mismatches ****\n"); + rc = send_dl_simple(PRIM_DL_REL, + PRIM_OP_INDICATION, lctx); + msgb_free(msg); + /* go to idle state */ + lapd_dl_flush_tx(dl); + lapd_dl_flush_send(dl); + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + return 0; + } + } + /* set Vs, Vr and Va to 0 */ + dl->v_send = dl->v_recv = dl->v_ack = 0; + /* clear tx_hist */ + lapd_dl_flush_hist(dl); + /* enter multiple-frame-established state */ + lapd_dl_newstate(dl, LAPD_STATE_MF_EST); + /* send outstanding frames, if any (resume / reconnect) */ + lapd_send_i(lctx, __LINE__); + /* send notification to L3 */ + rc = send_dl_simple(PRIM_DL_EST, PRIM_OP_CONFIRM, lctx); + msgb_free(msg); + break; + case LAPD_U_FRMR: + LOGP(DLLAPD, LOGL_NOTICE, "Frame reject received\n"); + /* send MDL ERROR INIDCATION to L3 */ + mdl_error(MDL_CAUSE_FRMR, lctx); + msgb_free(msg); + /* reestablish */ + if (!dl->reestablish) + break; + LOGP(DLLAPD, LOGL_NOTICE, "Performing reestablishment.\n"); + rc = lapd_reestablish(dl); + break; + default: + /* G.3.1 */ + LOGP(DLLAPD, LOGL_NOTICE, "Unnumbered frame not allowed.\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx); + return -EINVAL; + } + return rc; +} + +/* Receive a LAPD S (Supervisory) message from L1 */ +static int lapd_rx_s(struct msgb *msg, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + int length = lctx->length; + + if (length > 0 || lctx->more) { + /* G.4.3 If a supervisory frame is received with L>0 or + * with the M bit set to "1", an MDL-ERROR-INDICATION + * primitive with cause "S frame with incorrect + * parameters" is sent to the mobile management entity. */ + LOGP(DLLAPD, LOGL_NOTICE, + "S frame with incorrect parameters\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_SFRM_INC_PARAM, lctx); + return -EIO; + } + + if (lctx->cr == dl->cr.rem2loc.resp + && lctx->p_f + && dl->state != LAPD_STATE_TIMER_RECOV) { + /* 5.4.2.2: Inidcate error on supervisory reponse F=1 */ + LOGP(DLLAPD, LOGL_NOTICE, "S frame response with F=1 error\n"); + mdl_error(MDL_CAUSE_UNSOL_SPRV_RESP, lctx); + } + + switch (dl->state) { + case LAPD_STATE_IDLE: + /* if P=1, respond DM with F=1 (5.2.2) */ + /* 5.4.5 all other frame types shall be discarded */ + if (lctx->p_f) + lapd_send_dm(lctx); /* F=P */ + /* fall though */ + case LAPD_STATE_SABM_SENT: + case LAPD_STATE_DISC_SENT: + LOGP(DLLAPD, LOGL_NOTICE, "S frame ignored in this state\n"); + msgb_free(msg); + return 0; + } + switch (lctx->s_u) { + case LAPD_S_RR: + LOGP(DLLAPD, LOGL_INFO, "RR received in state %s\n", + lapd_state_names[dl->state]); + /* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */ + lapd_acknowledge(lctx); + + /* 5.5.3.2 */ + if (lctx->cr == dl->cr.rem2loc.cmd + && lctx->p_f) { + if (!dl->own_busy && !dl->seq_err_cond) { + LOGP(DLLAPD, LOGL_INFO, "RR frame command " + "with polling bit set and we are not " + "busy, so we reply with RR frame " + "response\n"); + lapd_send_rr(lctx, 1, 0); + /* NOTE: In case of sequence error condition, + * the REJ frame has been transmitted when + * entering the condition, so it has not be + * done here + */ + } else if (dl->own_busy) { + LOGP(DLLAPD, LOGL_INFO, "RR frame command " + "with polling bit set and we are busy, " + "so we reply with RR frame response\n"); + lapd_send_rnr(lctx, 1, 0); + } + } else if (lctx->cr == dl->cr.rem2loc.resp + && lctx->p_f + && dl->state == LAPD_STATE_TIMER_RECOV) { + LOGP(DLLAPD, LOGL_INFO, "RR response with F==1, " + "and we are in timer recovery state, so " + "we leave that state\n"); + /* V(S) to the N(R) in the RR frame */ + dl->v_send = lctx->n_recv; + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + /* 5.5.7 Clear timer recovery condition */ + lapd_dl_newstate(dl, LAPD_STATE_MF_EST); + } + /* Send message, if possible due to acknowledged data */ + lapd_send_i(lctx, __LINE__); + + break; + case LAPD_S_RNR: + LOGP(DLLAPD, LOGL_INFO, "RNR received in state %s\n", + lapd_state_names[dl->state]); + /* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */ + lapd_acknowledge(lctx); + + /* 5.5.5 */ + /* Set peer receiver busy condition */ + dl->peer_busy = 1; + + if (lctx->p_f) { + if (lctx->cr == dl->cr.rem2loc.cmd) { + if (!dl->own_busy) { + LOGP(DLLAPD, LOGL_INFO, "RNR poll " + "command and we are not busy, " + "so we reply with RR final " + "response\n"); + /* Send RR with F=1 */ + lapd_send_rr(lctx, 1, 0); + } else { + LOGP(DLLAPD, LOGL_INFO, "RNR poll " + "command and we are busy, so " + "we reply with RNR final " + "response\n"); + /* Send RNR with F=1 */ + lapd_send_rnr(lctx, 1, 0); + } + } else if (dl->state == LAPD_STATE_TIMER_RECOV) { + LOGP(DLLAPD, LOGL_INFO, "RNR poll response " + "and we in timer recovery state, so " + "we leave that state\n"); + /* 5.5.7 Clear timer recovery condition */ + lapd_dl_newstate(dl, LAPD_STATE_MF_EST); + /* V(S) to the N(R) in the RNR frame */ + dl->v_send = lctx->n_recv; + } + } else + LOGP(DLLAPD, LOGL_INFO, "RNR not polling/final state " + "received\n"); + + /* Send message, if possible due to acknowledged data */ + lapd_send_i(lctx, __LINE__); + + break; + case LAPD_S_REJ: + LOGP(DLLAPD, LOGL_INFO, "REJ received in state %s\n", + lapd_state_names[dl->state]); + /* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */ + lapd_acknowledge(lctx); + + /* 5.5.4.1 */ + if (dl->state != LAPD_STATE_TIMER_RECOV) { + /* Clear an existing peer receiver busy condition */ + dl->peer_busy = 0; + /* V(S) and V(A) to the N(R) in the REJ frame */ + dl->v_send = dl->v_ack = lctx->n_recv; + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + /* 5.5.3.2 */ + if (lctx->cr == dl->cr.rem2loc.cmd && lctx->p_f) { + if (!dl->own_busy && !dl->seq_err_cond) { + LOGP(DLLAPD, LOGL_INFO, "REJ poll " + "command not in timer recovery " + "state and not in own busy " + "condition received, so we " + "respond with RR final " + "response\n"); + lapd_send_rr(lctx, 1, 0); + /* NOTE: In case of sequence error + * condition, the REJ frame has been + * transmitted when entering the + * condition, so it has not be done + * here + */ + } else if (dl->own_busy) { + LOGP(DLLAPD, LOGL_INFO, "REJ poll " + "command not in timer recovery " + "state and in own busy " + "condition received, so we " + "respond with RNR final " + "response\n"); + lapd_send_rnr(lctx, 1, 0); + } + } else + LOGP(DLLAPD, LOGL_INFO, "REJ response or not " + "polling command not in timer recovery " + "state received\n"); + /* send MDL ERROR INIDCATION to L3 */ + if (lctx->cr == dl->cr.rem2loc.resp && lctx->p_f) { + mdl_error(MDL_CAUSE_UNSOL_SPRV_RESP, lctx); + } + + } else if (lctx->cr == dl->cr.rem2loc.resp && lctx->p_f) { + LOGP(DLLAPD, LOGL_INFO, "REJ poll response in timer " + "recovery state received\n"); + /* Clear an existing peer receiver busy condition */ + dl->peer_busy = 0; + /* V(S) and V(A) to the N(R) in the REJ frame */ + dl->v_send = dl->v_ack = lctx->n_recv; + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + /* 5.5.7 Clear timer recovery condition */ + lapd_dl_newstate(dl, LAPD_STATE_MF_EST); + } else { + /* Clear an existing peer receiver busy condition */ + dl->peer_busy = 0; + /* V(S) and V(A) to the N(R) in the REJ frame */ + dl->v_send = dl->v_ack = lctx->n_recv; + /* 5.5.3.2 */ + if (lctx->cr == dl->cr.rem2loc.cmd && lctx->p_f) { + if (!dl->own_busy && !dl->seq_err_cond) { + LOGP(DLLAPD, LOGL_INFO, "REJ poll " + "command in timer recovery " + "state and not in own busy " + "condition received, so we " + "respond with RR final " + "response\n"); + lapd_send_rr(lctx, 1, 0); + /* NOTE: In case of sequence error + * condition, the REJ frame has been + * transmitted when entering the + * condition, so it has not be done + * here + */ + } else if (dl->own_busy) { + LOGP(DLLAPD, LOGL_INFO, "REJ poll " + "command in timer recovery " + "state and in own busy " + "condition received, so we " + "respond with RNR final " + "response\n"); + lapd_send_rnr(lctx, 1, 0); + } + } else + LOGP(DLLAPD, LOGL_INFO, "REJ response or not " + "polling command in timer recovery " + "state received\n"); + } + + /* FIXME: 5.5.4.2 2) */ + + /* Send message, if possible due to acknowledged data */ + lapd_send_i(lctx, __LINE__); + + break; + default: + /* G.3.1 */ + LOGP(DLLAPD, LOGL_NOTICE, "Supervisory frame not allowed.\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx); + return -EINVAL; + } + msgb_free(msg); + return 0; +} + +/* Receive a LAPD I (Information) message from L1 */ +static int lapd_rx_i(struct msgb *msg, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + //uint8_t nr = lctx->n_recv; + uint8_t ns = lctx->n_send; + int length = lctx->length; + int rc; + + LOGP(DLLAPD, LOGL_INFO, "I received in state %s\n", + lapd_state_names[dl->state]); + + /* G.2.2 Wrong value of the C/R bit */ + if (lctx->cr == dl->cr.rem2loc.resp) { + LOGP(DLLAPD, LOGL_NOTICE, "I frame response not allowed\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_FRM_UNIMPL, lctx); + return -EINVAL; + } + + if (length == 0 || length > lctx->n201) { + /* G.4.2 If the length indicator of an I frame is set + * to a numerical value L>N201 or L=0, an MDL-ERROR-INDICATION + * primitive with cause "I frame with incorrect length" + * is sent to the mobile management entity. */ + LOGP(DLLAPD, LOGL_NOTICE, "I frame length not allowed\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_IFRM_INC_LEN, lctx); + return -EIO; + } + + /* G.4.2 If the numerical value of L is L<N201 and the M + * bit is set to "1", then an MDL-ERROR-INDICATION primitive with + * cause "I frame with incorrect use of M bit" is sent to the + * mobile management entity. */ + if (lctx->more && length < lctx->n201) { + LOGP(DLLAPD, LOGL_NOTICE, "I frame with M bit too short\n"); + msgb_free(msg); + mdl_error(MDL_CAUSE_IFRM_INC_MBITS, lctx); + return -EIO; + } + + switch (dl->state) { + case LAPD_STATE_IDLE: + /* if P=1, respond DM with F=1 (5.2.2) */ + /* 5.4.5 all other frame types shall be discarded */ + if (lctx->p_f) + lapd_send_dm(lctx); /* F=P */ + /* fall though */ + case LAPD_STATE_SABM_SENT: + case LAPD_STATE_DISC_SENT: + LOGP(DLLAPD, LOGL_NOTICE, "I frame ignored in this state\n"); + msgb_free(msg); + return 0; + } + + /* 5.7.1: N(s) sequence error */ + if (ns != dl->v_recv) { + LOGP(DLLAPD, LOGL_NOTICE, "N(S) sequence error: N(S)=%u, " + "V(R)=%u\n", ns, dl->v_recv); + /* discard data */ + msgb_free(msg); + if (!dl->seq_err_cond) { + /* FIXME: help me understand what exactly todo here + dl->seq_err_cond = 1; + */ + lapd_send_rej(lctx, lctx->p_f); + } else { + } + return -EIO; + } + dl->seq_err_cond = 0; + + /* Increment receiver state */ + dl->v_recv = inc_mod(dl->v_recv, dl->v_range); + LOGP(DLLAPD, LOGL_INFO, "incrementing V(R) to %u\n", dl->v_recv); + + /* 5.5.3.1: Acknowlege all transmitted frames up the the N(R)-1 */ + lapd_acknowledge(lctx); /* V(A) is also set here */ + + /* Only if we are not in own receiver busy condition */ + if (!dl->own_busy) { + /* if the frame carries a complete segment */ + if (!lctx->more && !dl->rcv_buffer) { + LOGP(DLLAPD, LOGL_INFO, "message in single I frame\n"); + /* send a DATA INDICATION to L3 */ + msg->len = length; + msg->tail = msg->data + length; + rc = send_dl_l3(PRIM_DL_DATA, PRIM_OP_INDICATION, lctx, + msg); + } else { + /* create rcv_buffer */ + if (!dl->rcv_buffer) { + LOGP(DLLAPD, LOGL_INFO, "message in multiple " + "I frames (first message)\n"); + dl->rcv_buffer = lapd_msgb_alloc(dl->maxf, + "LAPD RX"); + dl->rcv_buffer->l3h = dl->rcv_buffer->data; + } + /* concat. rcv_buffer */ + if (msgb_l3len(dl->rcv_buffer) + length > dl->maxf) { + LOGP(DLLAPD, LOGL_NOTICE, "Received frame " + "overflow!\n"); + } else { + memcpy(msgb_put(dl->rcv_buffer, length), + msg->l3h, length); + } + /* if the last segment was received */ + if (!lctx->more) { + LOGP(DLLAPD, LOGL_INFO, "message in multiple " + "I frames (last message)\n"); + rc = send_dl_l3(PRIM_DL_DATA, + PRIM_OP_INDICATION, lctx, + dl->rcv_buffer); + dl->rcv_buffer = NULL; + } else + LOGP(DLLAPD, LOGL_INFO, "message in multiple " + "I frames (next message)\n"); + msgb_free(msg); + + } + } else + LOGP(DLLAPD, LOGL_INFO, "I frame ignored during own receiver " + "busy condition\n"); + + /* Check for P bit */ + if (lctx->p_f) { + /* 5.5.2.1 */ + /* check if we are not in own receiver busy */ + if (!dl->own_busy) { + LOGP(DLLAPD, LOGL_INFO, "we are not busy, send RR\n"); + /* Send RR with F=1 */ + rc = lapd_send_rr(lctx, 1, 0); + } else { + LOGP(DLLAPD, LOGL_INFO, "we are busy, send RNR\n"); + /* Send RNR with F=1 */ + rc = lapd_send_rnr(lctx, 1, 0); + } + } else { + /* 5.5.2.2 */ + /* check if we are not in own receiver busy */ + if (!dl->own_busy) { + /* NOTE: V(R) is already set above */ + rc = lapd_send_i(lctx, __LINE__); + if (rc) { + LOGP(DLLAPD, LOGL_INFO, "we are not busy and " + "have no pending data, send RR\n"); + /* Send RR with F=0 */ + return lapd_send_rr(lctx, 0, 0); + } + /* all I or one RR is sent, we are done */ + return 0; + } else { + LOGP(DLLAPD, LOGL_INFO, "we are busy, send RNR\n"); + /* Send RNR with F=0 */ + rc = lapd_send_rnr(lctx, 0, 0); + } + } + + /* Send message, if possible due to acknowledged data */ + lapd_send_i(lctx, __LINE__); + + return rc; +} + +/* Receive a LAPD message from L1 */ +int lapd_ph_data_ind(struct msgb *msg, struct lapd_msg_ctx *lctx) +{ + int rc; + + switch (lctx->format) { + case LAPD_FORM_U: + rc = lapd_rx_u(msg, lctx); + break; + case LAPD_FORM_S: + rc = lapd_rx_s(msg, lctx); + break; + case LAPD_FORM_I: + rc = lapd_rx_i(msg, lctx); + break; + default: + LOGP(DLLAPD, LOGL_NOTICE, "unknown LAPD format\n"); + msgb_free(msg); + rc = -EINVAL; + } + return rc; +} + +/* L3 -> L2 */ + +/* send unit data */ +static int lapd_udata_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + struct msgb *msg = dp->oph.msg; + struct lapd_msg_ctx nctx; + + memcpy(&nctx, lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.cmd; + nctx.format = LAPD_FORM_U; + nctx.s_u = LAPD_U_UI; + /* keep nctx.p_f */ + nctx.length = msg->len; + nctx.more = 0; + + return dl->send_ph_data_req(&nctx, msg); +} + +/* request link establishment */ +static int lapd_est_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + struct msgb *msg = dp->oph.msg; + struct lapd_msg_ctx nctx; + + if (msg->len) + LOGP(DLLAPD, LOGL_INFO, "perform establishment with content " + "(SABM)\n"); + else + LOGP(DLLAPD, LOGL_INFO, "perform normal establishm. (SABM)\n"); + + /* Flush send-queue */ + /* Clear send-buffer */ + lapd_dl_flush_send(dl); + /* be sure that history is empty */ + lapd_dl_flush_hist(dl); + + /* save message context for further use */ + memcpy(&dl->lctx, lctx, sizeof(dl->lctx)); + + /* Discard partly received L3 message */ + if (dl->rcv_buffer) { + msgb_free(dl->rcv_buffer); + dl->rcv_buffer = NULL; + } + + /* assemble message */ + memcpy(&nctx, &dl->lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.cmd; + nctx.format = LAPD_FORM_U; + nctx.s_u = (dl->use_sabme) ? LAPD_U_SABME : LAPD_U_SABM; + nctx.p_f = 1; + nctx.length = msg->len; + nctx.more = 0; + + /* Transmit-buffer carries exactly one segment */ + dl->tx_hist[0].msg = lapd_msgb_alloc(msg->len, "HIST"); + msgb_put(dl->tx_hist[0].msg, msg->len); + if (msg->len) + memcpy(dl->tx_hist[0].msg->data, msg->l3h, msg->len); + dl->tx_hist[0].more = 0; + /* set Vs to 0, because it is used as index when resending SABM */ + dl->v_send = 0; + + /* Set states */ + dl->own_busy = dl->peer_busy = 0; + dl->retrans_ctr = 0; + lapd_dl_newstate(dl, LAPD_STATE_SABM_SENT); + + /* Tramsmit and start T200 */ + dl->send_ph_data_req(&nctx, msg); + osmo_timer_schedule(&dl->t200, dl->t200_sec, dl->t200_usec); + + return 0; +} + +/* send data */ +static int lapd_data_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + struct msgb *msg = dp->oph.msg; + + LOGP(DLLAPD, LOGL_INFO, "writing message to send-queue\n"); + + /* Write data into the send queue */ + msgb_enqueue(&dl->send_queue, msg); + + /* Send message, if possible */ + lapd_send_i(&dl->lctx, __LINE__); + + return 0; +} + +/* Send next I frame from queued/buffered data */ +static int lapd_send_i(struct lapd_msg_ctx *lctx, int line) +{ + struct lapd_datalink *dl = lctx->dl; + uint8_t k = dl->k; + uint8_t h; + struct msgb *msg; + int length, left; + int rc = - 1; /* we sent nothing */ + struct lapd_msg_ctx nctx; + + + LOGP(DLLAPD, LOGL_INFO, "%s() called from line %d\n", __func__, line); + + next_frame: + + if (dl->peer_busy) { + LOGP(DLLAPD, LOGL_INFO, "peer busy, not sending\n"); + return rc; + } + + if (dl->state == LAPD_STATE_TIMER_RECOV) { + LOGP(DLLAPD, LOGL_INFO, "timer recovery, not sending\n"); + return rc; + } + + /* If the send state variable V(S) is equal to V(A) plus k + * (where k is the maximum number of outstanding I frames - see + * subclause 5.8.4), the data link layer entity shall not transmit any + * new I frames, but shall retransmit an I frame as a result + * of the error recovery procedures as described in subclauses 5.5.4 and + * 5.5.7. */ + if (dl->v_send == add_mod(dl->v_ack, k, dl->v_range)) { + LOGP(DLLAPD, LOGL_INFO, "k frames outstanding, not sending " + "more (k=%u V(S)=%u V(A)=%u)\n", k, dl->v_send, + dl->v_ack); + return rc; + } + + h = do_mod(dl->v_send, dl->range_hist); + + /* if we have no tx_hist yet, we create it */ + if (!dl->tx_hist[h].msg) { + /* Get next message into send-buffer, if any */ + if (!dl->send_buffer) { + next_message: + dl->send_out = 0; + dl->send_buffer = msgb_dequeue(&dl->send_queue); + /* No more data to be sent */ + if (!dl->send_buffer) + return rc; + LOGP(DLLAPD, LOGL_INFO, "get message from " + "send-queue\n"); + } + + /* How much is left in the send-buffer? */ + left = msgb_l3len(dl->send_buffer) - dl->send_out; + /* Segment, if data exceeds N201 */ + length = left; + if (length > lctx->n201) + length = lctx->n201; + LOGP(DLLAPD, LOGL_INFO, "msg-len %d sent %d left %d N201 %d " + "length %d first byte %02x\n", + msgb_l3len(dl->send_buffer), dl->send_out, left, + lctx->n201, length, dl->send_buffer->l3h[0]); + /* If message in send-buffer is completely sent */ + if (left == 0) { + msgb_free(dl->send_buffer); + dl->send_buffer = NULL; + goto next_message; + } + + LOGP(DLLAPD, LOGL_INFO, "send I frame %sV(S)=%d\n", + (left > length) ? "segment " : "", dl->v_send); + + /* Create I frame (segment) and transmit-buffer content */ + msg = lapd_msgb_alloc(length, "LAPD I"); + msg->l3h = msgb_put(msg, length); + /* assemble message */ + memcpy(&nctx, &dl->lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.cmd; + nctx.format = LAPD_FORM_I; + nctx.p_f = 0; + nctx.n_send = dl->v_send; + nctx.n_recv = dl->v_recv; + nctx.length = length; + if (left > length) + nctx.more = 1; + else + nctx.more = 0; + if (length) + memcpy(msg->l3h, dl->send_buffer->l3h + dl->send_out, + length); + /* store in tx_hist */ + dl->tx_hist[h].msg = lapd_msgb_alloc(msg->len, "HIST"); + msgb_put(dl->tx_hist[h].msg, msg->len); + if (length) + memcpy(dl->tx_hist[h].msg->data, msg->l3h, msg->len); + dl->tx_hist[h].more = nctx.more; + /* Add length to track how much is already in the tx buffer */ + dl->send_out += length; + } else { + LOGP(DLLAPD, LOGL_INFO, "resend I frame from tx buffer " + "V(S)=%d\n", dl->v_send); + + /* Create I frame (segment) from tx_hist */ + length = dl->tx_hist[h].msg->len; + msg = lapd_msgb_alloc(length, "LAPD I resend"); + msg->l3h = msgb_put(msg, length); + /* assemble message */ + memcpy(&nctx, &dl->lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.cmd; + nctx.format = LAPD_FORM_I; + nctx.p_f = 0; + nctx.n_send = dl->v_send; + nctx.n_recv = dl->v_recv; + nctx.length = length; + nctx.more = dl->tx_hist[h].more; + if (length) + memcpy(msg->l3h, dl->tx_hist[h].msg->data, length); + } + + /* The value of the send state variable V(S) shall be incremented by 1 + * at the end of the transmission of the I frame */ + dl->v_send = inc_mod(dl->v_send, dl->v_range); + + /* If timer T200 is not running at the time right before transmitting a + * frame, when the PH-READY-TO-SEND primitive is received from the + * physical layer., it shall be set. */ + if (!osmo_timer_pending(&dl->t200)) { + osmo_timer_schedule(&dl->t200, dl->t200_sec, dl->t200_usec); + /* reset Timer T203, if running */ + if (osmo_timer_pending(&dl->t203)) { + LOGP(DLLAPD, LOGL_INFO, "stop T203\n"); + osmo_timer_del(&dl->t203); + } + } + + dl->send_ph_data_req(&nctx, msg); + + rc = 0; /* we sent something */ + goto next_frame; +} + +/* request link suspension */ +static int lapd_susp_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + struct msgb *msg = dp->oph.msg; + + LOGP(DLLAPD, LOGL_INFO, "perform suspension\n"); + + /* put back the send-buffer to the send-queue (first position) */ + if (dl->send_buffer) { + LOGP(DLLAPD, LOGL_INFO, "put frame in sendbuffer back to " + "queue\n"); + llist_add(&dl->send_buffer->list, &dl->send_queue); + dl->send_buffer = NULL; + } else + LOGP(DLLAPD, LOGL_INFO, "no frame in sendbuffer\n"); + + /* Clear transmit buffer, but keep send buffer */ + lapd_dl_flush_tx(dl); + /* Stop timers */ + if (osmo_timer_pending(&dl->t203)) { + LOGP(DLLAPD, LOGL_INFO, "stop T203\n"); + osmo_timer_del(&dl->t203); + } + osmo_timer_del(&dl->t200); + + msgb_free(msg); + + return send_dl_simple(PRIM_DL_SUSP, PRIM_OP_CONFIRM, &dl->lctx); +} + +/* requesst resume or reconnect of link */ +static int lapd_res_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + struct msgb *msg = dp->oph.msg; + struct lapd_msg_ctx nctx; + + LOGP(DLLAPD, LOGL_INFO, "perform re-establishment (SABM) length=%d\n", + msg->len); + + /* be sure that history is empty */ + lapd_dl_flush_hist(dl); + + /* save message context for further use */ + memcpy(&dl->lctx, lctx, sizeof(dl->lctx)); + + /* Replace message in the send-buffer (reconnect) */ + if (dl->send_buffer) + msgb_free(dl->send_buffer); + dl->send_out = 0; + if (msg && msg->len) { + /* Write data into the send buffer, to be sent first */ + dl->send_buffer = msg; + } + + /* Discard partly received L3 message */ + if (dl->rcv_buffer) { + msgb_free(dl->rcv_buffer); + dl->rcv_buffer = NULL; + } + + /* Create new msgb (old one is now free) */ + msg = lapd_msgb_alloc(0, "LAPD SABM"); + msg->l3h = msg->data; + /* assemble message */ + memcpy(&nctx, &dl->lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.cmd; + nctx.format = LAPD_FORM_U; + nctx.s_u = (dl->use_sabme) ? LAPD_U_SABME : LAPD_U_SABM; + nctx.p_f = 1; + nctx.length = 0; + nctx.more = 0; + + dl->tx_hist[0].msg = lapd_msgb_alloc(msg->len, "HIST"); + msgb_put(dl->tx_hist[0].msg, msg->len); + if (msg->len) + memcpy(dl->tx_hist[0].msg->data, msg->l3h, msg->len); + dl->tx_hist[0].more = 0; + /* set Vs to 0, because it is used as index when resending SABM */ + dl->v_send = 0; + + /* Set states */ + dl->own_busy = dl->peer_busy = 0; + dl->retrans_ctr = 0; + lapd_dl_newstate(dl, LAPD_STATE_SABM_SENT); + + /* Tramsmit and start T200 */ + dl->send_ph_data_req(&nctx, msg); + osmo_timer_schedule(&dl->t200, dl->t200_sec, dl->t200_usec); + + return 0; +} + +/* requesst release of link */ +static int lapd_rel_req(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + struct msgb *msg = dp->oph.msg; + struct lapd_msg_ctx nctx; + + /* local release */ + if (dp->u.rel_req.mode) { + LOGP(DLLAPD, LOGL_INFO, "perform local release\n"); + msgb_free(msg); + /* reset Timer T200 */ + osmo_timer_del(&dl->t200); + /* enter idle state */ + lapd_dl_newstate(dl, LAPD_STATE_IDLE); + /* flush buffers */ + lapd_dl_flush_tx(dl); + lapd_dl_flush_send(dl); + /* send notification to L3 */ + return send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, &dl->lctx); + } + + /* in case we are already disconnecting */ + if (dl->state == LAPD_STATE_DISC_SENT) + return -EBUSY; + + /* flush tx_hist */ + lapd_dl_flush_hist(dl); + + LOGP(DLLAPD, LOGL_INFO, "perform normal release (DISC)\n"); + + /* Push LAPD header on msgb */ + /* assemble message */ + memcpy(&nctx, &dl->lctx, sizeof(nctx)); + /* keep nctx.ldp */ + /* keep nctx.sapi */ + /* keep nctx.tei */ + nctx.cr = dl->cr.loc2rem.cmd; + nctx.format = LAPD_FORM_U; + nctx.s_u = LAPD_U_DISC; + nctx.p_f = 1; + nctx.length = 0; + nctx.more = 0; + + dl->tx_hist[0].msg = lapd_msgb_alloc(msg->len, "HIST"); + msgb_put(dl->tx_hist[0].msg, msg->len); + if (msg->len) + memcpy(dl->tx_hist[0].msg->data, msg->l3h, msg->len); + dl->tx_hist[0].more = 0; + /* set Vs to 0, because it is used as index when resending DISC */ + dl->v_send = 0; + + /* Set states */ + dl->own_busy = dl->peer_busy = 0; + dl->retrans_ctr = 0; + lapd_dl_newstate(dl, LAPD_STATE_DISC_SENT); + + /* Tramsmit and start T200 */ + dl->send_ph_data_req(&nctx, msg); + osmo_timer_schedule(&dl->t200, dl->t200_sec, dl->t200_usec); + + return 0; +} + +/* request release of link in idle state */ +static int lapd_rel_req_idle(struct osmo_dlsap_prim *dp, + struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + struct msgb *msg = dp->oph.msg; + + msgb_free(msg); + + /* send notification to L3 */ + return send_dl_simple(PRIM_DL_REL, PRIM_OP_CONFIRM, &dl->lctx); +} + +/* statefull handling for DL SAP messages from L3 */ +static struct l2downstate { + uint32_t states; + int prim, op; + const char *name; + int (*rout) (struct osmo_dlsap_prim *dp, + struct lapd_msg_ctx *lctx); +} l2downstatelist[] = { + /* create and send UI command */ + {ALL_STATES, + PRIM_DL_UNIT_DATA, PRIM_OP_REQUEST, + "DL-UNIT-DATA-REQUEST", lapd_udata_req}, + + /* create and send SABM command */ + {SBIT(LAPD_STATE_IDLE), + PRIM_DL_EST, PRIM_OP_REQUEST, + "DL-ESTABLISH-REQUEST", lapd_est_req}, + + /* create and send I command */ + {SBIT(LAPD_STATE_MF_EST) | + SBIT(LAPD_STATE_TIMER_RECOV), + PRIM_DL_DATA, PRIM_OP_REQUEST, + "DL-DATA-REQUEST", lapd_data_req}, + + /* suspend datalink */ + {SBIT(LAPD_STATE_MF_EST) | + SBIT(LAPD_STATE_TIMER_RECOV), + PRIM_DL_SUSP, PRIM_OP_REQUEST, + "DL-SUSPEND-REQUEST", lapd_susp_req}, + + /* create and send SABM command (resume) */ + {SBIT(LAPD_STATE_MF_EST) | + SBIT(LAPD_STATE_TIMER_RECOV), + PRIM_DL_RES, PRIM_OP_REQUEST, + "DL-RESUME-REQUEST", lapd_res_req}, + + /* create and send SABM command (reconnect) */ + {SBIT(LAPD_STATE_IDLE) | + SBIT(LAPD_STATE_MF_EST) | + SBIT(LAPD_STATE_TIMER_RECOV), + PRIM_DL_RECON, PRIM_OP_REQUEST, + "DL-RECONNECT-REQUEST", lapd_res_req}, + + /* create and send DISC command */ + {SBIT(LAPD_STATE_SABM_SENT) | + SBIT(LAPD_STATE_MF_EST) | + SBIT(LAPD_STATE_TIMER_RECOV) | + SBIT(LAPD_STATE_DISC_SENT), + PRIM_DL_REL, PRIM_OP_REQUEST, + "DL-RELEASE-REQUEST", lapd_rel_req}, + + /* release in idle state */ + {SBIT(LAPD_STATE_IDLE), + PRIM_DL_REL, PRIM_OP_REQUEST, + "DL-RELEASE-REQUEST", lapd_rel_req_idle}, +}; + +#define L2DOWNSLLEN \ + (sizeof(l2downstatelist) / sizeof(struct l2downstate)) + +int lapd_recv_dlsap(struct osmo_dlsap_prim *dp, struct lapd_msg_ctx *lctx) +{ + struct lapd_datalink *dl = lctx->dl; + int i, supported = 0; + struct msgb *msg = dp->oph.msg; + int rc; + + /* find function for current state and message */ + for (i = 0; i < L2DOWNSLLEN; i++) { + if (dp->oph.primitive == l2downstatelist[i].prim + && dp->oph.operation == l2downstatelist[i].op) { + supported = 1; + if ((SBIT(dl->state) & l2downstatelist[i].states)) + break; + } + } + if (!supported) { + LOGP(DLLAPD, LOGL_NOTICE, "Message %u/%u unsupported.\n", + dp->oph.primitive, dp->oph.operation); + msgb_free(msg); + return 0; + } + if (i == L2DOWNSLLEN) { + LOGP(DLLAPD, LOGL_NOTICE, "Message %u/%u unhandled at this " + "state %s.\n", dp->oph.primitive, dp->oph.operation, + lapd_state_names[dl->state]); + msgb_free(msg); + return 0; + } + + LOGP(DLLAPD, LOGL_INFO, "Message %s received in state %s\n", + l2downstatelist[i].name, lapd_state_names[dl->state]); + + rc = l2downstatelist[i].rout(dp, lctx); + + return rc; +} + diff --git a/src/gsm/lapdm.c b/src/gsm/lapdm.c index a2212785..9e7172d6 100644 --- a/src/gsm/lapdm.c +++ b/src/gsm/lapdm.c @@ -1,7 +1,7 @@ /* GSM LAPDm (TS 04.06) implementation */ /* (C) 2010-2011 by Harald Welte <laforge@gnumonks.org> - * (C) 2010 by Andreas Eversberg <jolly@eversberg.eu> + * (C) 2010-2011 by Andreas Eversberg <jolly@eversberg.eu> * * All Rights Reserved * @@ -27,36 +27,6 @@ /*! \file lapdm.c */ -/*! - * Notes on Buffering: rcv_buffer, tx_queue, tx_hist, send_buffer, send_queue - * - * RX data is stored in the rcv_buffer (pointer). If the message is complete, it - * is removed from rcv_buffer pointer and forwarded to L3. If the RX data is - * received while there is an incomplete rcv_buffer, it is appended to it. - * - * TX data is stored in the send_queue first. When transmitting a frame, - * the first message in the send_queue is moved to the send_buffer. There it - * resides until all fragments are acknowledged. Fragments to be sent by I - * frames are stored in the tx_hist buffer for resend, if required. Also the - * current fragment is copied into the tx_queue. There it resides until it is - * forwarded to layer 1. - * - * In case we have SAPI 0, we only have a window size of 1, so the unack- - * nowledged message resides always in the send_buffer. In case of a suspend, - * it can be written back to the first position of the send_queue. - * - * The layer 1 normally sends a PH-READY-TO-SEND. But because we use - * asynchronous transfer between layer 1 and layer 2 (serial link), we must - * send a frame before layer 1 reaches the right timeslot to send it. So we - * move the tx_queue to layer 1 when there is not already a pending frame, and - * wait until acknowledge after the frame has been sent. If we receive an - * acknowledge, we can send the next frame from the buffer, if any. - * - * The moving of tx_queue to layer 1 may also trigger T200, if desired. Also it - * will trigger next I frame, if possible. - * - */ - #include <stdio.h> #include <stdint.h> #include <string.h> @@ -84,6 +54,7 @@ #define LAPDm_SAPI_SMS 3 #define LAPDm_ADDR(lpd, sapi, cr) ((((lpd) & 0x3) << 5) | (((sapi) & 0x7) << 2) | (((cr) & 0x1) << 1) | 0x1) +#define LAPDm_ADDR_LPD(addr) (((addr) >> 5) & 0x3) #define LAPDm_ADDR_SAPI(addr) (((addr) >> 2) & 0x7) #define LAPDm_ADDR_CR(addr) (((addr) >> 1) & 0x1) #define LAPDm_ADDR_EA(addr) ((addr) & 0x1) @@ -105,19 +76,11 @@ #define LAPDm_CTRL_I_Ns(ctrl) (((ctrl) & 0xE) >> 1) #define LAPDm_CTRL_Nr(ctrl) (((ctrl) & 0xE0) >> 5) -/* TS 04.06 Table 4 / Section 3.8.1 */ -#define LAPDm_U_SABM 0x7 -#define LAPDm_U_DM 0x3 -#define LAPDm_U_UI 0x0 -#define LAPDm_U_DISC 0x8 -#define LAPDm_U_UA 0xC - -#define LAPDm_S_RR 0x0 -#define LAPDm_S_RNR 0x1 -#define LAPDm_S_REJ 0x2 - #define LAPDm_LEN(len) ((len << 2) | 0x1) #define LAPDm_MORE 0x2 +#define LAPDm_EL 0x1 + +#define LAPDm_U_UI 0x0 /* TS 04.06 Section 5.8.3 */ #define N201_AB_SACCH 18 @@ -137,19 +100,8 @@ #define N200_TR_FACCH_FR 34 #define N200_TR_EFACCH_FR 48 #define N200_TR_FACCH_HR 29 -/* FIXME: this depends on chan type */ -#define N200 N200_TR_SACCH - -#define CR_MS2BS_CMD 0 -#define CR_MS2BS_RESP 1 -#define CR_BS2MS_CMD 1 -#define CR_BS2MS_RESP 0 - -/* Set T200 to 1 Second (OpenBTS uses 900ms) */ -#define T200 1, 0 - -/* k value for each SAPI */ -static uint8_t k_sapi[] = {1, 1, 1, 1, 1, 1, 1, 1}; +/* FIXME: set N200 depending on chan_nr */ +#define N200 N200_TR_SDCCH enum lapdm_format { LAPDm_FMT_A, @@ -159,36 +111,22 @@ enum lapdm_format { LAPDm_FMT_B4, }; -static void lapdm_t200_cb(void *data); -static int rslms_send_i(struct lapdm_msg_ctx *mctx, int line); - -/* UTILITY FUNCTIONS */ - -static inline uint8_t inc_mod8(uint8_t x) -{ - return (x + 1) & 7; -} - -static inline uint8_t add_mod8(uint8_t x, uint8_t y) -{ - return (x + y) & 7; -} - -static inline uint8_t sub_mod8(uint8_t x, uint8_t y) -{ - return (x - y) & 7; /* handle negative results correctly */ -} +static int lapdm_send_ph_data_req(struct lapd_msg_ctx *lctx, struct msgb *msg); +static int send_rslms_dlsap(struct osmo_dlsap_prim *dp, + struct lapd_msg_ctx *lctx); static void lapdm_dl_init(struct lapdm_datalink *dl, struct lapdm_entity *entity) { memset(dl, 0, sizeof(*dl)); - INIT_LLIST_HEAD(&dl->send_queue); - INIT_LLIST_HEAD(&dl->tx_queue); - dl->state = LAPDm_STATE_IDLE; - dl->t200.data = dl; - dl->t200.cb = &lapdm_t200_cb; dl->entity = entity; + lapd_dl_init(&dl->dl, 1, 8, 200); + dl->dl.reestablish = 0; /* GSM uses no reestablish */ + dl->dl.send_ph_data_req = lapdm_send_ph_data_req; + dl->dl.send_dlsap = send_rslms_dlsap; + dl->dl.n200_est_rel = N200_EST_REL; + dl->dl.n200 = N200; + dl->dl.t203_sec = 0; dl->dl.t203_usec = 0; } /*! \brief initialize a LAPDm entity and all datalinks inside @@ -215,35 +153,10 @@ void lapdm_entity_init(struct lapdm_entity *le, enum lapdm_mode mode) void lapdm_channel_init(struct lapdm_channel *lc, enum lapdm_mode mode) { lapdm_entity_init(&lc->lapdm_acch, mode); + /* FIXME: this depends on chan type */ lapdm_entity_init(&lc->lapdm_dcch, mode); } -static void lapdm_dl_flush_send(struct lapdm_datalink *dl) -{ - struct msgb *msg; - - /* Flush send-queue */ - while ((msg = msgb_dequeue(&dl->send_queue))) - msgb_free(msg); - - /* Clear send-buffer */ - if (dl->send_buffer) { - msgb_free(dl->send_buffer); - dl->send_buffer = NULL; - } -} - -static void lapdm_dl_flush_tx(struct lapdm_datalink *dl) -{ - struct msgb *msg; - unsigned int i; - - while ((msg = msgb_dequeue(&dl->tx_queue))) - msgb_free(msg); - for (i = 0; i < 8; i++) - dl->tx_length[i] = 0; -} - /*! \brief flush and release all resoures in LAPDm entity */ void lapdm_entity_exit(struct lapdm_entity *le) { @@ -252,10 +165,7 @@ void lapdm_entity_exit(struct lapdm_entity *le) for (i = 0; i < ARRAY_SIZE(le->datalink); i++) { dl = &le->datalink[i]; - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - if (dl->rcv_buffer) - msgb_free(dl->rcv_buffer); + lapd_dl_exit(&dl->dl); } } @@ -270,14 +180,6 @@ void lapdm_channel_exit(struct lapdm_channel *lc) lapdm_entity_exit(&lc->lapdm_dcch); } -static void lapdm_dl_newstate(struct lapdm_datalink *dl, uint32_t state) -{ - LOGP(DLLAPDM, LOGL_INFO, "new state %s -> %s\n", - lapdm_state_names[dl->state], lapdm_state_names[state]); - - dl->state = state; -} - static struct lapdm_datalink *datalink_for_sapi(struct lapdm_entity *le, uint8_t sapi) { switch (sapi) { @@ -305,7 +207,7 @@ static void lapdm_pad_msgb(struct msgb *msg, uint8_t n201) uint8_t *data; if (pad_len < 0) { - LOGP(DLLAPDM, LOGL_ERROR, + LOGP(DLLAPD, LOGL_ERROR, "cannot pad message that is already too big!\n"); return; } @@ -328,17 +230,17 @@ static int rslms_sendmsg(struct msgb *msg, struct lapdm_entity *le) /* write a frame into the tx queue */ static int tx_ph_data_enqueue(struct lapdm_datalink *dl, struct msgb *msg, - uint8_t chan_nr, uint8_t link_id, uint8_t n201) + uint8_t chan_nr, uint8_t link_id, uint8_t pad) { struct lapdm_entity *le = dl->entity; struct osmo_phsap_prim pp; /* if there is a pending message, queue it */ if (le->tx_pending || le->flags & LAPDM_ENT_F_POLLING_ONLY) { - *msgb_push(msg, 1) = n201; + *msgb_push(msg, 1) = pad; *msgb_push(msg, 1) = link_id; *msgb_push(msg, 1) = chan_nr; - msgb_enqueue(&dl->tx_queue, msg); + msgb_enqueue(&dl->dl.tx_queue, msg); return -EBUSY; } @@ -349,7 +251,7 @@ static int tx_ph_data_enqueue(struct lapdm_datalink *dl, struct msgb *msg, /* send the frame now */ le->tx_pending = 0; /* disabled flow control */ - lapdm_pad_msgb(msg, n201); + lapdm_pad_msgb(msg, pad); return le->l1_prim_cb(&pp.oph, le->l1_ctx); } @@ -366,7 +268,7 @@ static struct msgb *tx_dequeue_msgb(struct lapdm_entity *le) /* next */ i = (i + 1) % n; dl = &le->datalink[i]; - if ((msg = msgb_dequeue(&dl->tx_queue))) + if ((msg = msgb_dequeue(&dl->dl.tx_queue))) break; } while (i != last); @@ -383,7 +285,7 @@ static struct msgb *tx_dequeue_msgb(struct lapdm_entity *le) int lapdm_phsap_dequeue_prim(struct lapdm_entity *le, struct osmo_phsap_prim *pp) { struct msgb *msg; - uint8_t n201; + uint8_t pad; msg = tx_dequeue_msgb(le); if (!msg) @@ -398,11 +300,11 @@ int lapdm_phsap_dequeue_prim(struct lapdm_entity *le, struct osmo_phsap_prim *pp msgb_pull(msg, 1); pp->u.data.link_id = *msg->data; msgb_pull(msg, 1); - n201 = *msg->data; + pad = *msg->data; msgb_pull(msg, 1); /* Pad the frame, we can transmit now */ - lapdm_pad_msgb(msg, n201); + lapdm_pad_msgb(msg, pad); return 0; } @@ -486,1142 +388,161 @@ static int rsl_rll_error(uint8_t cause, struct lapdm_msg_ctx *mctx) { struct msgb *msg; - LOGP(DLLAPDM, LOGL_NOTICE, "sending MDL-ERROR-IND %d\n", cause); + LOGP(DLLAPD, LOGL_NOTICE, "sending MDL-ERROR-IND %d\n", cause); msg = rsl_rll_simple(RSL_MT_ERROR_IND, mctx->chan_nr, mctx->link_id, 1); + msg->l2h = msgb_put(msg, sizeof(struct abis_rsl_rll_hdr)); msgb_tlv_put(msg, RSL_IE_RLM_CAUSE, 1, &cause); return rslms_sendmsg(msg, mctx->dl->entity); } -static int check_length_ind(struct lapdm_msg_ctx *mctx, uint8_t length_ind) -{ - if (!(length_ind & 0x01)) { - /* G.4.1 If the EL bit is set to "0", an MDL-ERROR-INDICATION - * primitive with cause "frame not implemented" is sent to the - * mobile management entity. */ - LOGP(DLLAPDM, LOGL_NOTICE, - "we don't support multi-octet length\n"); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); - return -EINVAL; - } - return 0; -} - -static int lapdm_send_resend(struct lapdm_datalink *dl) -{ - struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm resend"); - int length; - - /* Resend SABM/DISC from tx_hist */ - length = dl->tx_length[0]; - msg->l2h = msgb_put(msg, length); - memcpy(msg->l2h, dl->tx_hist[dl->V_send], length); - - return tx_ph_data_enqueue(dl, msg, dl->mctx.chan_nr, dl->mctx.link_id, - dl->mctx.n201); -} - -static int lapdm_send_ua(struct lapdm_msg_ctx *mctx, uint8_t len, uint8_t *data) +/* DLSAP L2 -> L3 (RSLms) */ +static int send_rslms_dlsap(struct osmo_dlsap_prim *dp, + struct lapd_msg_ctx *lctx) { - uint8_t sapi = mctx->link_id & 7; - uint8_t f_bit = LAPDm_CTRL_PF_BIT(mctx->ctrl); - struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm UA"); - struct lapdm_entity *le = mctx->dl->entity; - - msg->l2h = msgb_put(msg, 3 + len); - msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); - msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_UA, f_bit); - msg->l2h[2] = LAPDm_LEN(len); - if (len) - memcpy(msg->l2h + 3, data, len); - - return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, - mctx->n201); -} - -static int lapdm_send_dm(struct lapdm_msg_ctx *mctx) -{ - uint8_t sapi = mctx->link_id & 7; - uint8_t f_bit = LAPDm_CTRL_PF_BIT(mctx->ctrl); - struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm DM"); - struct lapdm_entity *le = mctx->dl->entity; - - msg->l2h = msgb_put(msg, 3); - msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); - msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_DM, f_bit); - msg->l2h[2] = 0; - - return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, - mctx->n201); -} - -static int lapdm_send_rr(struct lapdm_msg_ctx *mctx, uint8_t f_bit) -{ - uint8_t sapi = mctx->link_id & 7; - struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm RR"); - struct lapdm_entity *le = mctx->dl->entity; - - msg->l2h = msgb_put(msg, 3); - msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); - msg->l2h[1] = LAPDm_CTRL_S(mctx->dl->V_recv, LAPDm_S_RR, f_bit); - msg->l2h[2] = LAPDm_LEN(0); - - return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, - mctx->n201); -} - -static int lapdm_send_rnr(struct lapdm_msg_ctx *mctx, uint8_t f_bit) -{ - uint8_t sapi = mctx->link_id & 7; - struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm RNR"); - struct lapdm_entity *le = mctx->dl->entity; - - msg->l2h = msgb_put(msg, 3); - msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); - msg->l2h[1] = LAPDm_CTRL_S(mctx->dl->V_recv, LAPDm_S_RNR, f_bit); - msg->l2h[2] = LAPDm_LEN(0); - - return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, - mctx->n201); -} - -static int lapdm_send_rej(struct lapdm_msg_ctx *mctx, uint8_t f_bit) -{ - uint8_t sapi = mctx->link_id & 7; - struct msgb *msg = msgb_alloc_headroom(23+10, 10, "LAPDm REJ"); - struct lapdm_entity *le = mctx->dl->entity; - - msg->l2h = msgb_put(msg, 3); - msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.resp); - msg->l2h[1] = LAPDm_CTRL_S(mctx->dl->V_recv, LAPDm_S_REJ, f_bit); - msg->l2h[2] = LAPDm_LEN(0); - - return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, - mctx->n201); -} - -/* Timer callback on T200 expiry */ -static void lapdm_t200_cb(void *data) -{ - struct lapdm_datalink *dl = data; - - LOGP(DLLAPDM, LOGL_INFO, "lapdm_t200_cb(%p) state=%u\n", dl, dl->state); - - switch (dl->state) { - case LAPDm_STATE_SABM_SENT: - /* 5.4.1.3 */ - if (dl->retrans_ctr + 1 >= N200_EST_REL + 1) { - /* send RELEASE INDICATION to L3 */ - send_rll_simple(RSL_MT_REL_IND, &dl->mctx); - /* send MDL ERROR INIDCATION to L3 */ - rsl_rll_error(RLL_CAUSE_T200_EXPIRED, &dl->mctx); - /* flush tx buffers */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - /* go back to idle state */ - lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); - /* NOTE: we must not change any other states or buffers - * and queues, since we may reconnect after handover - * failure. the buffered messages is replaced there */ + struct lapd_datalink *dl = lctx->dl; + struct lapdm_datalink *mdl = + container_of(dl, struct lapdm_datalink, dl); + struct lapdm_msg_ctx *mctx = &mdl->mctx; + uint8_t rll_msg = 0; + + switch (dp->oph.primitive) { + case PRIM_DL_EST: + switch (dp->oph.operation) { + case PRIM_OP_INDICATION: + rll_msg = RSL_MT_EST_IND; break; - } - /* retransmit SABM command */ - lapdm_send_resend(dl); - /* increment re-transmission counter */ - dl->retrans_ctr++; - /* restart T200 (PH-READY-TO-SEND) */ - osmo_timer_schedule(&dl->t200, T200); - break; - case LAPDm_STATE_DISC_SENT: - /* 5.4.4.3 */ - if (dl->retrans_ctr + 1 >= N200_EST_REL + 1) { - /* send RELEASE INDICATION to L3 */ - send_rll_simple(RSL_MT_REL_CONF, &dl->mctx); - /* send MDL ERROR INIDCATION to L3 */ - rsl_rll_error(RLL_CAUSE_T200_EXPIRED, &dl->mctx); - /* flush buffers */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - /* go back to idle state */ - lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); - /* NOTE: we must not change any other states or buffers - * and queues, since we may reconnect after handover - * failure. the buffered messages is replaced there */ + case PRIM_OP_CONFIRM: + rll_msg = RSL_MT_EST_CONF; break; - } - /* retransmit DISC command */ - lapdm_send_resend(dl); - /* increment re-transmission counter */ - dl->retrans_ctr++; - /* restart T200 (PH-READY-TO-SEND) */ - osmo_timer_schedule(&dl->t200, T200); - break; - case LAPDm_STATE_MF_EST: - /* 5.5.7 */ - dl->retrans_ctr = 0; - lapdm_dl_newstate(dl, LAPDm_STATE_TIMER_RECOV); - /* fall through */ - case LAPDm_STATE_TIMER_RECOV: - dl->retrans_ctr++; - if (dl->retrans_ctr < N200) { - /* retransmit I frame (V_s-1) with P=1, if any */ - if (dl->tx_length[sub_mod8(dl->V_send, 1)]) { - struct msgb *msg; - int length; - - LOGP(DLLAPDM, LOGL_INFO, "retransmit last frame " - "V(S)=%d\n", sub_mod8(dl->V_send, 1)); - /* Create I frame (segment) from tx_hist */ - length = dl->tx_length[sub_mod8(dl->V_send, 1)]; - msg = msgb_alloc_headroom(23+10, 10, "LAPDm I"); - msg->l2h = msgb_put(msg, length); - memcpy(msg->l2h, - dl->tx_hist[sub_mod8(dl->V_send, 1)], - length); - msg->l2h[1] = LAPDm_CTRL_I(dl->V_recv, - sub_mod8(dl->V_send, 1), 1); /* P=1 */ - tx_ph_data_enqueue(dl, msg, dl->mctx.chan_nr, - dl->mctx.link_id, dl->mctx.n201); - } else { - /* OR send appropriate supervision frame with P=1 */ - if (!dl->own_busy && !dl->seq_err_cond) { - lapdm_send_rr(&dl->mctx, 1); - /* NOTE: In case of sequence error - * condition, the REJ frame has been - * transmitted when entering the - * condition, so it has not be done - * here - */ - } else if (dl->own_busy) { - lapdm_send_rnr(&dl->mctx, 1); - } else { - LOGP(DLLAPDM, LOGL_INFO, "unhandled, " - "pls. fix\n"); - } - } - /* restart T200 (PH-READY-TO-SEND) */ - osmo_timer_schedule(&dl->t200, T200); - } else { - /* send MDL ERROR INIDCATION to L3 */ - rsl_rll_error(RLL_CAUSE_T200_EXPIRED, &dl->mctx); + default: + ; } break; - default: - LOGP(DLLAPDM, LOGL_INFO, "T200 expired in unexpected " - "dl->state %u\n", dl->state); - } -} - -/* 5.5.3.1: Common function to acknowlege frames up to the given N(R) value */ -static void lapdm_acknowledge(struct lapdm_msg_ctx *mctx) -{ - struct lapdm_datalink *dl = mctx->dl; - uint8_t nr = LAPDm_CTRL_Nr(mctx->ctrl); - int s = 0, rej = 0, t200_reset = 0; - int i; - - /* supervisory frame ? */ - if (LAPDm_CTRL_is_S(mctx->ctrl)) - s = 1; - /* REJ frame ? */ - if (s && LAPDm_CTRL_S_BITS(mctx->ctrl) == LAPDm_S_REJ) - rej = 1; - - /* Flush all transmit buffers of acknowledged frames */ - for (i = dl->V_ack; i != nr; i = inc_mod8(i)) { - if (dl->tx_length[i]) { - dl->tx_length[i] = 0; - LOGP(DLLAPDM, LOGL_INFO, "ack frame %d\n", i); - } - } - - if (dl->state != LAPDm_STATE_TIMER_RECOV) { - /* When not in the timer recovery condition, the data - * link layer entity shall reset the timer T200 on - * receipt of a valid I frame with N(R) higher than V(A), - * or an REJ with an N(R) equal to V(A). */ - if ((!rej && nr != dl->V_ack) - || (rej && nr == dl->V_ack)) { - LOGP(DLLAPDM, LOGL_INFO, "reset t200\n"); - t200_reset = 1; - osmo_timer_del(&dl->t200); - /* 5.5.3.1 Note 1 + 2 imply timer recovery cond. */ - } - /* 5.7.4: N(R) sequence error - * N(R) is called valid, if and only if - * (N(R)-V(A)) mod 8 <= (V(S)-V(A)) mod 8. - */ - if (sub_mod8(nr, dl->V_ack) > sub_mod8(dl->V_send, dl->V_ack)) { - LOGP(DLLAPDM, LOGL_NOTICE, "N(R) sequence error\n"); - rsl_rll_error(RLL_CAUSE_SEQ_ERR, mctx); - } - } - - /* V(A) shall be set to the value of N(R) */ - dl->V_ack = nr; - - /* If T200 has been reset by the receipt of an I, RR or RNR frame, - * and if there are outstanding I frames, restart T200 */ - if (t200_reset && !rej) { - if (dl->tx_length[dl->V_send - 1]) { - LOGP(DLLAPDM, LOGL_INFO, "start T200, due to unacked I " - "frame(s)\n"); - osmo_timer_schedule(&dl->t200, T200); - } - } -} - -/* L1 -> L2 */ - -/* Receive a LAPDm U (Unnumbered) message from L1 */ -static int lapdm_rx_u(struct msgb *msg, struct lapdm_msg_ctx *mctx) -{ - struct lapdm_datalink *dl = mctx->dl; - struct lapdm_entity *le = dl->entity; - uint8_t length; - int rc; - int rsl_msg; - - switch (LAPDm_CTRL_U_BITS(mctx->ctrl)) { - case LAPDm_U_SABM: - rsl_msg = RSL_MT_EST_IND; - - LOGP(DLLAPDM, LOGL_INFO, "SABM received\n"); - /* 5.7.1 */ - dl->seq_err_cond = 0; - /* G.2.2 Wrong value of the C/R bit */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp) { - LOGP(DLLAPDM, LOGL_NOTICE, "SABM response error\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); - return -EINVAL; - } - - length = msg->l2h[2] >> 2; - /* G.4.5 If SABM is received with L>N201 or with M bit - * set, AN MDL-ERROR-INDICATION is sent to MM. - */ - if ((msg->l2h[2] & LAPDm_MORE) || length + 3 > mctx->n201) { - LOGP(DLLAPDM, LOGL_NOTICE, "SABM too large error\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_UFRM_INC_PARAM, mctx); - return -EIO; - } - - /* Must be Format B */ - rc = check_length_ind(mctx, msg->l2h[2]); - if (rc < 0) { - msgb_free(msg); - return rc; - } - switch (dl->state) { - case LAPDm_STATE_IDLE: - /* Set chan_nr and link_id for established connection */ - memset(&dl->mctx, 0, sizeof(dl->mctx)); - dl->mctx.dl = dl; - dl->mctx.chan_nr = mctx->chan_nr; - dl->mctx.link_id = mctx->link_id; - dl->mctx.n201 = mctx->n201; + case PRIM_DL_DATA: + switch (dp->oph.operation) { + case PRIM_OP_INDICATION: + rll_msg = RSL_MT_DATA_IND; break; - case LAPDm_STATE_MF_EST: - if (length == 0) { - rsl_msg = RSL_MT_EST_CONF; - break; - } - LOGP(DLLAPDM, LOGL_INFO, "SABM command, multiple " - "frame established state\n"); - /* check for contention resoultion */ - if (dl->tx_hist[0][2] >> 2) { - LOGP(DLLAPDM, LOGL_NOTICE, "SABM not allowed " - "during contention resolution\n"); - rsl_rll_error(RLL_CAUSE_SABM_INFO_NOTALL, mctx); - } - msgb_free(msg); - return 0; - case LAPDm_STATE_DISC_SENT: - /* 5.4.6.2 send DM with F=P */ - lapdm_send_dm(mctx); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - msgb_free(msg); - return send_rll_simple(RSL_MT_REL_CONF, mctx); default: - lapdm_send_ua(mctx, length, msg->l2h + 3); - msgb_free(msg); - return 0; - } - /* send UA response */ - lapdm_send_ua(mctx, length, msg->l2h + 3); - /* set Vs, Vr and Va to 0 */ - dl->V_send = dl->V_recv = dl->V_ack = 0; - /* clear tx_hist */ - dl->tx_length[0] = 0; - /* enter multiple-frame-established state */ - lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); - /* send notification to L3 */ - if (length == 0) { - /* 5.4.1.2 Normal establishment procedures */ - rc = send_rll_simple(rsl_msg, mctx); - msgb_free(msg); - } else { - /* 5.4.1.4 Contention resolution establishment */ - msg->l3h = msg->l2h + 3; - msgb_pull_l2h(msg); - rc = send_rslms_rll_l3(rsl_msg, mctx, msg); + ; } break; - case LAPDm_U_DM: - LOGP(DLLAPDM, LOGL_INFO, "DM received\n"); - /* G.2.2 Wrong value of the C/R bit */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd) { - LOGP(DLLAPDM, LOGL_NOTICE, "DM command error\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); - return -EINVAL; - } - if (!LAPDm_CTRL_PF_BIT(mctx->ctrl)) { - /* 5.4.1.2 DM responses with the F bit set to "0" - * shall be ignored. - */ - msgb_free(msg); - return 0; - } - switch (dl->state) { - case LAPDm_STATE_SABM_SENT: - break; - case LAPDm_STATE_MF_EST: - if (LAPDm_CTRL_PF_BIT(mctx->ctrl) == 1) { - LOGP(DLLAPDM, LOGL_INFO, "unsolicited DM " - "response\n"); - rsl_rll_error(RLL_CAUSE_UNSOL_DM_RESP, mctx); - } else { - LOGP(DLLAPDM, LOGL_INFO, "unsolicited DM " - "response, multiple frame established " - "state\n"); - rsl_rll_error(RLL_CAUSE_UNSOL_DM_RESP_MF, mctx); - } - msgb_free(msg); - return 0; - case LAPDm_STATE_TIMER_RECOV: - /* DM is normal in case PF = 1 */ - if (LAPDm_CTRL_PF_BIT(mctx->ctrl) == 0) { - LOGP(DLLAPDM, LOGL_INFO, "unsolicited DM " - "response, multiple frame established " - "state\n"); - rsl_rll_error(RLL_CAUSE_UNSOL_DM_RESP_MF, mctx); - msgb_free(msg); - return 0; - } - break; - case LAPDm_STATE_DISC_SENT: - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - /* go to idle state */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); - rc = send_rll_simple(RSL_MT_REL_CONF, mctx); - msgb_free(msg); - return 0; - case LAPDm_STATE_IDLE: - /* 5.4.5 all other frame types shall be discarded */ + case PRIM_DL_UNIT_DATA: + switch (dp->oph.operation) { + case PRIM_OP_INDICATION: + return send_rslms_rll_l3_ui(mctx, dp->oph.msg); default: - LOGP(DLLAPDM, LOGL_INFO, "unsolicited DM response! " - "(discarding)\n"); - msgb_free(msg); - return 0; + ; } - /* reset T200 */ - osmo_timer_del(&dl->t200); - rc = send_rll_simple(RSL_MT_REL_IND, mctx); - msgb_free(msg); break; - case LAPDm_U_UI: - LOGP(DLLAPDM, LOGL_INFO, "UI received\n"); - /* G.2.2 Wrong value of the C/R bit */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp) { - LOGP(DLLAPDM, LOGL_NOTICE, "UI indicates response " - "error\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); - return -EINVAL; - } - - length = msg->l2h[2] >> 2; - /* FIXME: G.4.5 If UI is received with L>N201 or with M bit - * set, AN MDL-ERROR-INDICATION is sent to MM. - */ - - if (mctx->lapdm_fmt == LAPDm_FMT_B4) { - length = N201_B4; - msg->l3h = msg->l2h + 2; - } else { - rc = check_length_ind(mctx, msg->l2h[2]); - if (rc < 0) { - msgb_free(msg); - return rc; - } - length = msg->l2h[2] >> 2; - msg->l3h = msg->l2h + 3; - } - /* do some length checks */ - if (length == 0) { - /* 5.3.3 UI frames received with the length indicator - * set to "0" shall be ignored - */ - LOGP(DLLAPDM, LOGL_INFO, "length=0 (discarding)\n"); - msgb_free(msg); - return 0; - } - switch (LAPDm_ADDR_SAPI(mctx->addr)) { - case LAPDm_SAPI_NORMAL: - case LAPDm_SAPI_SMS: + case PRIM_DL_REL: + switch (dp->oph.operation) { + case PRIM_OP_INDICATION: + rll_msg = RSL_MT_REL_IND; + break; + case PRIM_OP_CONFIRM: + rll_msg = RSL_MT_REL_CONF; break; default: - /* 5.3.3 UI frames with invalid SAPI values shall be - * discarded - */ - LOGP(DLLAPDM, LOGL_INFO, "sapi=%u (discarding)\n", - LAPDm_ADDR_SAPI(mctx->addr)); - msgb_free(msg); - return 0; + ; } - msgb_pull_l2h(msg); - rc = send_rslms_rll_l3_ui(mctx, msg); break; - case LAPDm_U_DISC: - rsl_msg = RSL_MT_REL_IND; - - LOGP(DLLAPDM, LOGL_INFO, "DISC received\n"); - /* flush buffers */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - /* 5.7.1 */ - dl->seq_err_cond = 0; - /* G.2.2 Wrong value of the C/R bit */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp) { - LOGP(DLLAPDM, LOGL_NOTICE, "DISC response error\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); - return -EINVAL; - } - length = msg->l2h[2] >> 2; - if (length > 0 || msg->l2h[2] & 0x02) { - /* G.4.4 If a DISC or DM frame is received with L>0 or - * with the M bit set to "1", an MDL-ERROR-INDICATION - * primitive with cause "U frame with incorrect - * parameters" is sent to the mobile management entity. - */ - LOGP(DLLAPDM, LOGL_NOTICE, - "U frame iwth incorrect parameters "); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_UFRM_INC_PARAM, mctx); - return -EIO; - } - switch (dl->state) { - case LAPDm_STATE_IDLE: - LOGP(DLLAPDM, LOGL_INFO, "DISC in idle state\n"); - /* send DM with F=P */ - msgb_free(msg); - return lapdm_send_dm(mctx); - case LAPDm_STATE_SABM_SENT: - LOGP(DLLAPDM, LOGL_INFO, "DISC in SABM state\n"); - /* 5.4.6.2 send DM with F=P */ - lapdm_send_dm(mctx); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - msgb_free(msg); - return send_rll_simple(RSL_MT_REL_IND, mctx); - case LAPDm_STATE_MF_EST: - case LAPDm_STATE_TIMER_RECOV: - LOGP(DLLAPDM, LOGL_INFO, "DISC in est state\n"); - break; - case LAPDm_STATE_DISC_SENT: - LOGP(DLLAPDM, LOGL_INFO, "DISC in disc state\n"); - rsl_msg = RSL_MT_REL_CONF; + case PRIM_DL_SUSP: + switch (dp->oph.operation) { + case PRIM_OP_CONFIRM: + rll_msg = RSL_MT_SUSP_CONF; break; default: - lapdm_send_ua(mctx, length, msg->l2h + 3); - msgb_free(msg); - return 0; + ; } - /* send UA response */ - lapdm_send_ua(mctx, length, msg->l2h + 3); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - /* enter idle state */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); - /* send notification to L3 */ - rc = send_rll_simple(rsl_msg, mctx); - msgb_free(msg); break; - case LAPDm_U_UA: - LOGP(DLLAPDM, LOGL_INFO, "UA received\n"); - /* G.2.2 Wrong value of the C/R bit */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd) { - LOGP(DLLAPDM, LOGL_NOTICE, "UA indicates command " - "error\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); - return -EINVAL; - } - - length = msg->l2h[2] >> 2; - /* G.4.5 If UA is received with L>N201 or with M bit - * set, AN MDL-ERROR-INDICATION is sent to MM. - */ - if ((msg->l2h[2] & LAPDm_MORE) || length + 3 > mctx->n201) { - LOGP(DLLAPDM, LOGL_NOTICE, "UA too large error\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_UFRM_INC_PARAM, mctx); - return -EIO; - } - - if (!LAPDm_CTRL_PF_BIT(mctx->ctrl)) { - /* 5.4.1.2 A UA response with the F bit set to "0" - * shall be ignored. - */ - LOGP(DLLAPDM, LOGL_INFO, "F=0 (discarding)\n"); - msgb_free(msg); - return 0; - } - switch (dl->state) { - case LAPDm_STATE_SABM_SENT: - break; - case LAPDm_STATE_MF_EST: - case LAPDm_STATE_TIMER_RECOV: - LOGP(DLLAPDM, LOGL_INFO, "unsolicited UA response! " - "(discarding)\n"); - rsl_rll_error(RLL_CAUSE_UNSOL_UA_RESP, mctx); - msgb_free(msg); - return 0; - case LAPDm_STATE_DISC_SENT: - LOGP(DLLAPDM, LOGL_INFO, "UA in disconnect state\n"); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - /* go to idle state */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); - rc = send_rll_simple(RSL_MT_REL_CONF, mctx); - msgb_free(msg); + case PRIM_MDL_ERROR: + switch (dp->oph.operation) { + case PRIM_OP_INDICATION: + rsl_rll_error(dp->u.error_ind.cause, mctx); + if (dp->oph.msg) + msgb_free(dp->oph.msg); return 0; - case LAPDm_STATE_IDLE: - /* 5.4.5 all other frame types shall be discarded */ default: - LOGP(DLLAPDM, LOGL_INFO, "unsolicited UA response! " - "(discarding)\n"); - msgb_free(msg); - return 0; - } - LOGP(DLLAPDM, LOGL_INFO, "UA in SABM state\n"); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - /* compare UA with SABME if contention resolution is applied */ - if (dl->tx_hist[0][2] >> 2) { - rc = check_length_ind(mctx, msg->l2h[2]); - if (rc < 0) { - rc = send_rll_simple(RSL_MT_REL_IND, mctx); - msgb_free(msg); - /* go to idle state */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); - return 0; - } - length = msg->l2h[2] >> 2; - if (length != (dl->tx_hist[0][2] >> 2) - || !!memcmp(dl->tx_hist[0] + 3, msg->l2h + 3, - length)) { - LOGP(DLLAPDM, LOGL_INFO, "**** UA response " - "mismatches ****\n"); - rc = send_rll_simple(RSL_MT_REL_IND, mctx); - msgb_free(msg); - /* go to idle state */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); - return 0; - } + ; } - /* set Vs, Vr and Va to 0 */ - dl->V_send = dl->V_recv = dl->V_ack = 0; - /* clear tx_hist */ - dl->tx_length[0] = 0; - /* enter multiple-frame-established state */ - lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); - /* send outstanding frames, if any (resume / reconnect) */ - rslms_send_i(mctx, __LINE__); - /* send notification to L3 */ - rc = send_rll_simple(RSL_MT_EST_CONF, mctx); - msgb_free(msg); break; default: - /* G.3.1 */ - LOGP(DLLAPDM, LOGL_NOTICE, "Unnumbered frame not allowed.\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); - return -EINVAL; + ; } - return rc; -} -/* Receive a LAPDm S (Supervisory) message from L1 */ -static int lapdm_rx_s(struct msgb *msg, struct lapdm_msg_ctx *mctx) -{ - struct lapdm_datalink *dl = mctx->dl; - struct lapdm_entity *le = dl->entity; - uint8_t length; - - length = msg->l2h[2] >> 2; - if (length > 0 || msg->l2h[2] & 0x02) { - /* G.4.3 If a supervisory frame is received with L>0 or - * with the M bit set to "1", an MDL-ERROR-INDICATION - * primitive with cause "S frame with incorrect - * parameters" is sent to the mobile management entity. */ - LOGP(DLLAPDM, LOGL_NOTICE, - "S frame with incorrect parameters\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_SFRM_INC_PARAM, mctx); - return -EIO; + if (!rll_msg) { + LOGP(DLLAPD, LOGL_ERROR, "Unsupported op %d, prim %d. Please " + "fix!\n", dp->oph.primitive, dp->oph.operation); + return -EINVAL; } - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp - && LAPDm_CTRL_PF_BIT(mctx->ctrl) - && dl->state != LAPDm_STATE_TIMER_RECOV) { - /* 5.4.2.2: Inidcate error on supervisory reponse F=1 */ - LOGP(DLLAPDM, LOGL_NOTICE, "S frame response with F=1 error\n"); - rsl_rll_error(RLL_CAUSE_UNSOL_SPRV_RESP, mctx); - } + if (!dp->oph.msg) + return send_rll_simple(rll_msg, mctx); - switch (dl->state) { - case LAPDm_STATE_IDLE: - /* if P=1, respond DM with F=1 (5.2.2) */ - /* 5.4.5 all other frame types shall be discarded */ - if (LAPDm_CTRL_PF_BIT(mctx->ctrl)) - lapdm_send_dm(mctx); /* F=P */ - /* fall though */ - case LAPDm_STATE_SABM_SENT: - case LAPDm_STATE_DISC_SENT: - LOGP(DLLAPDM, LOGL_NOTICE, "S frame ignored in this state\n"); - msgb_free(msg); - return 0; - } - switch (LAPDm_CTRL_S_BITS(mctx->ctrl)) { - case LAPDm_S_RR: - LOGP(DLLAPDM, LOGL_INFO, "RR received\n"); - /* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */ - lapdm_acknowledge(mctx); - - /* 5.5.3.2 */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd - && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { - if (!dl->own_busy && !dl->seq_err_cond) { - LOGP(DLLAPDM, LOGL_NOTICE, "RR frame command " - "with polling bit set and we are not " - "busy, so we reply with RR frame\n"); - lapdm_send_rr(mctx, 1); - /* NOTE: In case of sequence error condition, - * the REJ frame has been transmitted when - * entering the condition, so it has not be - * done here - */ - } else if (dl->own_busy) { - LOGP(DLLAPDM, LOGL_NOTICE, "RR frame command " - "with polling bit set and we are busy, " - "so we reply with RR frame\n"); - lapdm_send_rnr(mctx, 1); - } - } else if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp - && LAPDm_CTRL_PF_BIT(mctx->ctrl) - && dl->state == LAPDm_STATE_TIMER_RECOV) { - LOGP(DLLAPDM, LOGL_INFO, "RR response with F==1, " - "and we are in timer recovery state, so " - "we leave that state\n"); - /* V(S) to the N(R) in the RR frame */ - dl->V_send = LAPDm_CTRL_Nr(mctx->ctrl); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - /* 5.5.7 Clear timer recovery condition */ - lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); - } - /* Send message, if possible due to acknowledged data */ - rslms_send_i(mctx, __LINE__); + return send_rslms_rll_l3(rll_msg, mctx, dp->oph.msg); +} +/* send a data frame to layer 1 */ +static int lapdm_send_ph_data_req(struct lapd_msg_ctx *lctx, struct msgb *msg) +{ + uint8_t l3_len = msg->tail - msg->data; + struct lapd_datalink *dl = lctx->dl; + struct lapdm_datalink *mdl = + container_of(dl, struct lapdm_datalink, dl); + struct lapdm_msg_ctx *mctx = &mdl->mctx; + int format = lctx->format; + + /* prepend l2 header */ + msg->l2h = msgb_push(msg, 3); + msg->l2h[0] = LAPDm_ADDR(lctx->lpd, lctx->sapi, lctx->cr); + /* EA is set here too */ + switch (format) { + case LAPD_FORM_I: + msg->l2h[1] = LAPDm_CTRL_I(lctx->n_recv, lctx->n_send, + lctx->p_f); break; - case LAPDm_S_RNR: - LOGP(DLLAPDM, LOGL_INFO, "RNR received\n"); - /* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */ - lapdm_acknowledge(mctx); - - /* 5.5.5 */ - /* Set peer receiver busy condition */ - dl->peer_busy = 1; - - if (LAPDm_CTRL_PF_BIT(mctx->ctrl)) { - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd) { - if (!dl->own_busy) { - LOGP(DLLAPDM, LOGL_INFO, "RNR poll " - "command and we are not busy, " - "so we reply with RR final " - "response\n"); - /* Send RR with F=1 */ - lapdm_send_rr(mctx, 1); - } else { - LOGP(DLLAPDM, LOGL_INFO, "RNR poll " - "command and we are busy, so " - "we reply with RNR final " - "response\n"); - /* Send RNR with F=1 */ - lapdm_send_rnr(mctx, 1); - } - } else if (dl->state == LAPDm_STATE_TIMER_RECOV) { - LOGP(DLLAPDM, LOGL_INFO, "RNR poll response " - "and we in timer recovery state, so " - "we leave that state\n"); - /* 5.5.7 Clear timer recovery condition */ - lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); - /* V(S) to the N(R) in the RNR frame */ - dl->V_send = LAPDm_CTRL_Nr(mctx->ctrl); - } - } else - LOGP(DLLAPDM, LOGL_INFO, "RNR not polling/final state " - "received\n"); - - /* Send message, if possible due to acknowledged data */ - rslms_send_i(mctx, __LINE__); - + case LAPD_FORM_S: + msg->l2h[1] = LAPDm_CTRL_S(lctx->n_recv, lctx->s_u, lctx->p_f); break; - case LAPDm_S_REJ: - LOGP(DLLAPDM, LOGL_INFO, "REJ received\n"); - /* 5.5.3.1: Acknowlege all tx frames up the the N(R)-1 */ - lapdm_acknowledge(mctx); - - /* 5.5.4.1 */ - if (dl->state != LAPDm_STATE_TIMER_RECOV) { - /* Clear an existing peer receiver busy condition */ - dl->peer_busy = 0; - /* V(S) and V(A) to the N(R) in the REJ frame */ - dl->V_send = dl->V_ack = LAPDm_CTRL_Nr(mctx->ctrl); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - /* 5.5.3.2 */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd - && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { - if (!dl->own_busy && !dl->seq_err_cond) { - LOGP(DLLAPDM, LOGL_INFO, "REJ poll " - "command not in timer recovery " - "state and not in own busy " - "condition received, so we " - "respond with RR final " - "response\n"); - lapdm_send_rr(mctx, 1); - /* NOTE: In case of sequence error - * condition, the REJ frame has been - * transmitted when entering the - * condition, so it has not be done - * here - */ - } else if (dl->own_busy) { - LOGP(DLLAPDM, LOGL_INFO, "REJ poll " - "command not in timer recovery " - "state and in own busy " - "condition received, so we " - "respond with RNR final " - "response\n"); - lapdm_send_rnr(mctx, 1); - } - } else - LOGP(DLLAPDM, LOGL_INFO, "REJ response or not " - "polling command not in timer recovery " - "state received\n"); - /* send MDL ERROR INIDCATION to L3 */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp - && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { - rsl_rll_error(RLL_CAUSE_UNSOL_SPRV_RESP, mctx); - } - - } else if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp - && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { - LOGP(DLLAPDM, LOGL_INFO, "REJ poll response in timer " - "recovery state received\n"); - /* Clear an existing peer receiver busy condition */ - dl->peer_busy = 0; - /* 5.5.7 Clear timer recovery condition */ - lapdm_dl_newstate(dl, LAPDm_STATE_MF_EST); - /* V(S) and V(A) to the N(R) in the REJ frame */ - dl->V_send = dl->V_ack = LAPDm_CTRL_Nr(mctx->ctrl); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - } else { - /* Clear an existing peer receiver busy condition */ - dl->peer_busy = 0; - /* V(S) and V(A) to the N(R) in the REJ frame */ - dl->V_send = dl->V_ack = LAPDm_CTRL_Nr(mctx->ctrl); - /* 5.5.3.2 */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.cmd - && LAPDm_CTRL_PF_BIT(mctx->ctrl)) { - if (!dl->own_busy && !dl->seq_err_cond) { - LOGP(DLLAPDM, LOGL_INFO, "REJ poll " - "command in timer recovery " - "state and not in own busy " - "condition received, so we " - "respond with RR final " - "response\n"); - lapdm_send_rr(mctx, 1); - /* NOTE: In case of sequence error - * condition, the REJ frame has been - * transmitted when entering the - * condition, so it has not be done - * here - */ - } else if (dl->own_busy) { - LOGP(DLLAPDM, LOGL_INFO, "REJ poll " - "command in timer recovery " - "state and in own busy " - "condition received, so we " - "respond with RNR final " - "response\n"); - lapdm_send_rnr(mctx, 1); - } - } else - LOGP(DLLAPDM, LOGL_INFO, "REJ response or not " - "polling command in timer recovery " - "state received\n"); - } - - /* FIXME: 5.5.4.2 2) */ - - /* Send message, if possible due to acknowledged data */ - rslms_send_i(mctx, __LINE__); - + case LAPD_FORM_U: + msg->l2h[1] = LAPDm_CTRL_U(lctx->s_u, lctx->p_f); break; default: - /* G.3.1 */ - LOGP(DLLAPDM, LOGL_NOTICE, "Supervisory frame not allowed.\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); - return -EINVAL; - } - msgb_free(msg); - return 0; -} - -/* Receive a LAPDm I (Information) message from L1 */ -static int lapdm_rx_i(struct msgb *msg, struct lapdm_msg_ctx *mctx) -{ - struct lapdm_datalink *dl = mctx->dl; - struct lapdm_entity *le = dl->entity; - //uint8_t nr = LAPDm_CTRL_Nr(mctx->ctrl); - uint8_t ns = LAPDm_CTRL_I_Ns(mctx->ctrl); - uint8_t length; - int rc; - - LOGP(DLLAPDM, LOGL_NOTICE, "I received\n"); - - /* G.2.2 Wrong value of the C/R bit */ - if (LAPDm_ADDR_CR(mctx->addr) == le->cr.rem2loc.resp) { - LOGP(DLLAPDM, LOGL_NOTICE, "I frame response not allowed\n"); msgb_free(msg); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); return -EINVAL; } + msg->l2h[2] = LAPDm_LEN(l3_len); /* EL is set here too */ + if (lctx->more) + msg->l2h[2] |= LAPDm_MORE; - length = msg->l2h[2] >> 2; - if (length == 0 || length + 3 > mctx->n201) { - /* G.4.2 If the length indicator of an I frame is set - * to a numerical value L>N201 or L=0, an MDL-ERROR-INDICATION - * primitive with cause "I frame with incorrect length" - * is sent to the mobile management entity. */ - LOGP(DLLAPDM, LOGL_NOTICE, "I frame length not allowed\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_IFRM_INC_LEN, mctx); - return -EIO; - } - - /* G.4.2 If the numerical value of L is L<N201 and the M - * bit is set to "1", then an MDL-ERROR-INDICATION primitive with - * cause "I frame with incorrect use of M bit" is sent to the - * mobile management entity. */ - if ((msg->l2h[2] & LAPDm_MORE) && length + 3 < mctx->n201) { - LOGP(DLLAPDM, LOGL_NOTICE, "I frame with M bit too short\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_IFRM_INC_MBITS, mctx); - return -EIO; - } - - switch (dl->state) { - case LAPDm_STATE_IDLE: - /* if P=1, respond DM with F=1 (5.2.2) */ - /* 5.4.5 all other frame types shall be discarded */ - if (LAPDm_CTRL_PF_BIT(mctx->ctrl)) - lapdm_send_dm(mctx); /* F=P */ - /* fall though */ - case LAPDm_STATE_SABM_SENT: - case LAPDm_STATE_DISC_SENT: - LOGP(DLLAPDM, LOGL_NOTICE, "I frame ignored in this state\n"); - msgb_free(msg); - return 0; - } - - /* 5.7.1: N(s) sequence error */ - if (ns != dl->V_recv) { - LOGP(DLLAPDM, LOGL_NOTICE, "N(S) sequence error: N(S)=%u, " - "V(R)=%u\n", ns, dl->V_recv); - /* discard data */ - msgb_free(msg); - if (!dl->seq_err_cond) { - /* FIXME: help me understand what exactly todo here - dl->seq_err_cond = 1; - */ - lapdm_send_rej(mctx, LAPDm_CTRL_PF_BIT(mctx->ctrl)); - } else { - } - return -EIO; - } - dl->seq_err_cond = 0; - - /* Increment receiver state */ - dl->V_recv = inc_mod8(dl->V_recv); - LOGP(DLLAPDM, LOGL_NOTICE, "incrementing V(R) to %u\n", dl->V_recv); - - /* 5.5.3.1: Acknowlege all transmitted frames up the the N(R)-1 */ - lapdm_acknowledge(mctx); /* V(A) is also set here */ - - /* Only if we are not in own receiver busy condition */ - if (!dl->own_busy) { - /* if the frame carries a complete segment */ - if (!(msg->l2h[2] & LAPDm_MORE) - && !dl->rcv_buffer) { - LOGP(DLLAPDM, LOGL_INFO, "message in single I frame\n"); - /* send a DATA INDICATION to L3 */ - msg->l3h = msg->l2h + 3; - msgb_pull_l2h(msg); - msg->len = length; - msg->tail = msg->data + length; - rc = send_rslms_rll_l3(RSL_MT_DATA_IND, mctx, msg); - } else { - /* create rcv_buffer */ - if (!dl->rcv_buffer) { - LOGP(DLLAPDM, LOGL_INFO, "message in multiple I " - "frames (first message)\n"); - dl->rcv_buffer = msgb_alloc_headroom(200+56, 56, - "LAPDm RX"); - dl->rcv_buffer->l3h = dl->rcv_buffer->data; - } - /* concat. rcv_buffer */ - if (msgb_l3len(dl->rcv_buffer) + length > 200) { - LOGP(DLLAPDM, LOGL_NOTICE, "Received frame " - "overflow!\n"); - } else { - memcpy(msgb_put(dl->rcv_buffer, length), - msg->l2h + 3, length); - } - /* if the last segment was received */ - if (!(msg->l2h[2] & LAPDm_MORE)) { - LOGP(DLLAPDM, LOGL_INFO, "message in multiple I " - "frames (last message)\n"); - rc = send_rslms_rll_l3(RSL_MT_DATA_IND, mctx, - dl->rcv_buffer); - dl->rcv_buffer = NULL; - } else - LOGP(DLLAPDM, LOGL_INFO, "message in multiple I " - "frames (next message)\n"); - msgb_free(msg); - - } - } else - LOGP(DLLAPDM, LOGL_INFO, "I frame ignored during own receiver " - "busy condition\n"); - - /* Check for P bit */ - if (LAPDm_CTRL_PF_BIT(mctx->ctrl)) { - /* 5.5.2.1 */ - /* check if we are not in own receiver busy */ - if (!dl->own_busy) { - LOGP(DLLAPDM, LOGL_INFO, "we are not busy, send RR\n"); - /* Send RR with F=1 */ - rc = lapdm_send_rr(mctx, 1); - } else { - LOGP(DLLAPDM, LOGL_INFO, "we are busy, send RNR\n"); - /* Send RNR with F=1 */ - rc = lapdm_send_rnr(mctx, 1); - } - } else { - /* 5.5.2.2 */ - /* check if we are not in own receiver busy */ - if (!dl->own_busy) { - /* NOTE: V(R) is already set above */ - rc = rslms_send_i(mctx, __LINE__); - if (rc) { - LOGP(DLLAPDM, LOGL_INFO, "we are not busy and " - "have no pending data, send RR\n"); - /* Send RR with F=0 */ - return lapdm_send_rr(mctx, 0); - } - /* all I or one RR is sent, we are done */ - return 0; - } else { - LOGP(DLLAPDM, LOGL_INFO, "we are busy, send RNR\n"); - /* Send RNR with F=0 */ - rc = lapdm_send_rnr(mctx, 0); - } - } - - /* Send message, if possible due to acknowledged data */ - rslms_send_i(mctx, __LINE__); - - return rc; -} - -/* Receive a LAPDm message from L1 */ -static int lapdm_ph_data_ind(struct msgb *msg, struct lapdm_msg_ctx *mctx) -{ - int rc; - - /* G.2.3 EA bit set to "0" is not allowed in GSM */ - if (!LAPDm_ADDR_EA(mctx->addr)) { - LOGP(DLLAPDM, LOGL_NOTICE, "EA bit 0 is not allowed in GSM\n"); - msgb_free(msg); - rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, mctx); - return -EINVAL; - } - - if (LAPDm_CTRL_is_U(mctx->ctrl)) - rc = lapdm_rx_u(msg, mctx); - else if (LAPDm_CTRL_is_S(mctx->ctrl)) - rc = lapdm_rx_s(msg, mctx); - else if (LAPDm_CTRL_is_I(mctx->ctrl)) - rc = lapdm_rx_i(msg, mctx); - else { - LOGP(DLLAPDM, LOGL_NOTICE, "unknown LAPDm format\n"); - msgb_free(msg); - rc = -EINVAL; - } - return rc; + return tx_ph_data_enqueue(mctx->dl, msg, mctx->chan_nr, mctx->link_id, + 23); } /* input into layer2 (from layer 1) */ -static int l2_ph_data_ind(struct msgb *msg, struct lapdm_entity *le, uint8_t chan_nr, uint8_t link_id) +static int l2_ph_data_ind(struct msgb *msg, struct lapdm_entity *le, + uint8_t chan_nr, uint8_t link_id) { uint8_t cbits = chan_nr >> 3; uint8_t sapi; /* we cannot take SAPI from link_id, as L1 has no clue */ struct lapdm_msg_ctx mctx; + struct lapd_msg_ctx lctx; int rc = 0; + int n201; /* when we reach here, we have a msgb with l2h pointing to the raw * 23byte mac block. The l1h has already been purged. */ + memset(&mctx, 0, sizeof(mctx)); mctx.chan_nr = chan_nr; mctx.link_id = link_id; - mctx.addr = mctx.ctrl = 0; /* check for L1 chan_nr/link_id and determine LAPDm hdr format */ if (cbits == 0x10 || cbits == 0x12) { /* Format Bbis is used on BCCH and CCCH(PCH, NCH and AGCH) */ mctx.lapdm_fmt = LAPDm_FMT_Bbis; - mctx.n201 = N201_Bbis; + n201 = N201_Bbis; sapi = 0; } else { if (mctx.link_id & 0x40) { @@ -1630,12 +551,12 @@ static int l2_ph_data_ind(struct msgb *msg, struct lapdm_entity *le, uint8_t cha /* If sent by BTS, lapdm_fmt must be B4 */ if (le->mode == LAPDM_MODE_MS) { mctx.lapdm_fmt = LAPDm_FMT_B4; - mctx.n201 = N201_B4; - LOGP(DLLAPDM, LOGL_INFO, "fmt=B4\n"); + n201 = N201_B4; + LOGP(DLLAPD, LOGL_INFO, "fmt=B4\n"); } else { mctx.lapdm_fmt = LAPDm_FMT_B; - mctx.n201 = N201_AB_SACCH; - LOGP(DLLAPDM, LOGL_INFO, "fmt=B\n"); + n201 = N201_AB_SACCH; + LOGP(DLLAPD, LOGL_INFO, "fmt=B\n"); } /* SACCH frames have a two-byte L1 header that * OsmocomBB L1 doesn't strip */ @@ -1646,8 +567,8 @@ static int l2_ph_data_ind(struct msgb *msg, struct lapdm_entity *le, uint8_t cha sapi = (msg->l2h[0] >> 2) & 7; } else { mctx.lapdm_fmt = LAPDm_FMT_B; - LOGP(DLLAPDM, LOGL_INFO, "fmt=B\n"); - mctx.n201 = 23; // FIXME: select correct size by chan. + LOGP(DLLAPD, LOGL_INFO, "fmt=B\n"); + n201 = 20; // FIXME: select correct size by chan. sapi = (msg->l2h[0] >> 2) & 7; } } @@ -1655,7 +576,7 @@ static int l2_ph_data_ind(struct msgb *msg, struct lapdm_entity *le, uint8_t cha mctx.dl = datalink_for_sapi(le, sapi); /* G.2.1 No action on frames containing an unallocated SAPI. */ if (!mctx.dl) { - LOGP(DLLAPDM, LOGL_NOTICE, "Received frame for unsupported " + LOGP(DLLAPD, LOGL_NOTICE, "Received frame for unsupported " "SAPI %d!\n", sapi); msgb_free(msg); return -EIO; @@ -1665,17 +586,77 @@ static int l2_ph_data_ind(struct msgb *msg, struct lapdm_entity *le, uint8_t cha case LAPDm_FMT_A: case LAPDm_FMT_B: case LAPDm_FMT_B4: - mctx.addr = msg->l2h[0]; - if (!(mctx.addr & 0x01)) { - LOGP(DLLAPDM, LOGL_ERROR, "we don't support " - "multibyte addresses (discarding)\n"); + lctx.dl = &mctx.dl->dl; + /* obtain SAPI from address field */ + mctx.link_id |= LAPDm_ADDR_SAPI(msg->l2h[0]); + /* G.2.3 EA bit set to "0" is not allowed in GSM */ + if (!LAPDm_ADDR_EA(msg->l2h[0])) { + LOGP(DLLAPD, LOGL_NOTICE, "EA bit 0 is not allowed in " + "GSM\n"); msgb_free(msg); + rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, &mctx); return -EINVAL; } - mctx.ctrl = msg->l2h[1]; - /* obtain SAPI from address field */ - mctx.link_id |= LAPDm_ADDR_SAPI(mctx.addr); - rc = lapdm_ph_data_ind(msg, &mctx); + /* adress field */ + lctx.lpd = LAPDm_ADDR_LPD(msg->l2h[0]); + lctx.sapi = LAPDm_ADDR_SAPI(msg->l2h[0]); + lctx.cr = LAPDm_ADDR_CR(msg->l2h[0]); + /* command field */ + if (LAPDm_CTRL_is_I(msg->l2h[1])) { + lctx.format = LAPD_FORM_I; + lctx.n_send = LAPDm_CTRL_I_Ns(msg->l2h[1]); + lctx.n_recv = LAPDm_CTRL_Nr(msg->l2h[1]); + } else if (LAPDm_CTRL_is_S(msg->l2h[1])) { + lctx.format = LAPD_FORM_S; + lctx.n_recv = LAPDm_CTRL_Nr(msg->l2h[1]); + lctx.s_u = LAPDm_CTRL_S_BITS(msg->l2h[1]); + } else if (LAPDm_CTRL_is_U(msg->l2h[1])) { + lctx.format = LAPD_FORM_U; + lctx.s_u = LAPDm_CTRL_U_BITS(msg->l2h[1]); + } else + lctx.format = LAPD_FORM_UKN; + lctx.p_f = LAPDm_CTRL_PF_BIT(msg->l2h[1]); + if (lctx.sapi != LAPDm_SAPI_NORMAL + && lctx.sapi != LAPDm_SAPI_SMS + && lctx.format == LAPD_FORM_U + && lctx.s_u == LAPDm_U_UI) { + /* 5.3.3 UI frames with invalid SAPI values shall be + * discarded + */ + LOGP(DLLAPD, LOGL_INFO, "sapi=%u (discarding)\n", + lctx.sapi); + msgb_free(msg); + return 0; + } + if (mctx.lapdm_fmt == LAPDm_FMT_B4) { + lctx.n201 = n201; + lctx.length = n201; + lctx.more = 0; + msg->l3h = msg->l2h + 2; + msgb_pull_l2h(msg); + } else { + /* length field */ + if (!(msg->l2h[2] & LAPDm_EL)) { + /* G.4.1 If the EL bit is set to "0", an + * MDL-ERROR-INDICATION primitive with cause + * "frame not implemented" is sent to the + * mobile management entity. */ + LOGP(DLLAPD, LOGL_NOTICE, "we don't support " + "multi-octet length\n"); + msgb_free(msg); + rsl_rll_error(RLL_CAUSE_FRM_UNIMPL, &mctx); + return -EINVAL; + } + lctx.n201 = n201; + lctx.length = msg->l2h[2] >> 2; + lctx.more = !!(msg->l2h[2] & LAPDm_MORE); + msg->l3h = msg->l2h + 3; + msgb_pull_l2h(msg); + } + /* store context for messages from lapd */ + memcpy(&mctx.dl->mctx, &mctx, sizeof(mctx.dl->mctx)); + /* send to LAPD */ + rc = lapd_ph_data_ind(msg, &lctx); break; case LAPDm_FMT_Bter: /* FIXME */ @@ -1683,7 +664,7 @@ static int l2_ph_data_ind(struct msgb *msg, struct lapdm_entity *le, uint8_t cha break; case LAPDm_FMT_Bbis: /* directly pass up to layer3 */ - LOGP(DLLAPDM, LOGL_INFO, "fmt=Bbis UI\n"); + LOGP(DLLAPD, LOGL_INFO, "fmt=Bbis UI\n"); msg->l3h = msg->l2h; msgb_pull_l2h(msg); rc = send_rslms_rll_l3(RSL_MT_UNIT_DATA_IND, &mctx, msg); @@ -1731,7 +712,7 @@ int lapdm_phsap_up(struct osmo_prim_hdr *oph, struct lapdm_entity *le) int rc = 0; if (oph->sap != SAP_GSM_PH) { - LOGP(DLLAPDM, LOGL_ERROR, "primitive for unknown SAP %u\n", + LOGP(DLLAPD, LOGL_ERROR, "primitive for unknown SAP %u\n", oph->sap); return -ENODEV; } @@ -1739,7 +720,7 @@ int lapdm_phsap_up(struct osmo_prim_hdr *oph, struct lapdm_entity *le) switch (oph->primitive) { case PRIM_PH_DATA: if (oph->operation != PRIM_OP_INDICATION) { - LOGP(DLLAPDM, LOGL_ERROR, "PH_DATA is not INDICATION %u\n", + LOGP(DLLAPD, LOGL_ERROR, "PH_DATA is not INDICATION %u\n", oph->operation); return -ENODEV; } @@ -1748,7 +729,7 @@ int lapdm_phsap_up(struct osmo_prim_hdr *oph, struct lapdm_entity *le) break; case PRIM_PH_RTS: if (oph->operation != PRIM_OP_INDICATION) { - LOGP(DLLAPDM, LOGL_ERROR, "PH_RTS is not INDICATION %u\n", + LOGP(DLLAPD, LOGL_ERROR, "PH_RTS is not INDICATION %u\n", oph->operation); return -ENODEV; } @@ -1775,33 +756,44 @@ int lapdm_phsap_up(struct osmo_prim_hdr *oph, struct lapdm_entity *le) /* L3 -> L2 / RSLMS -> LAPDm */ +/* Set LAPDm context for established connection */ +static int set_lapdm_context(struct lapdm_datalink *dl, uint8_t chan_nr, + uint8_t link_id, int n201, uint8_t sapi) +{ + memset(&dl->mctx, 0, sizeof(dl->mctx)); + dl->mctx.dl = dl; + dl->mctx.chan_nr = chan_nr; + dl->mctx.link_id = link_id; + dl->dl.lctx.dl = &dl->dl; + dl->dl.lctx.n201 = n201; + dl->dl.lctx.sapi = sapi; + + return 0; +} + /* L3 requests establishment of data link */ static int rslms_rx_rll_est_req(struct msgb *msg, struct lapdm_datalink *dl) { - struct lapdm_entity *le = dl->entity; struct abis_rsl_rll_hdr *rllh = msgb_l2(msg); uint8_t chan_nr = rllh->chan_nr; uint8_t link_id = rllh->link_id; uint8_t sapi = rllh->link_id & 7; struct tlv_parsed tv; uint8_t length; - uint8_t n201 = 23; //FIXME + int n201 = 20; //FIXME + struct osmo_dlsap_prim dp; - /* Set chan_nr and link_id for established connection */ - memset(&dl->mctx, 0, sizeof(dl->mctx)); - dl->mctx.dl = dl; - dl->mctx.n201 = n201; - dl->mctx.chan_nr = chan_nr; - dl->mctx.link_id = link_id; + /* Set LAPDm context for established connection */ + set_lapdm_context(dl, chan_nr, link_id, n201, sapi); - rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh)); + rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg) - sizeof(*rllh)); if (TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) { - msg->l3h = TLVP_VAL(&tv, RSL_IE_L3_INFO); + msg->l3h = (uint8_t *) TLVP_VAL(&tv, RSL_IE_L3_INFO); /* contention resolution establishment procedure */ if (sapi != 0) { /* According to clause 6, the contention resolution * procedure is only permitted with SAPI value 0 */ - LOGP(DLLAPDM, LOGL_ERROR, "SAPI != 0 but contention" + LOGP(DLLAPD, LOGL_ERROR, "SAPI != 0 but contention" "resolution (discarding)\n"); msgb_free(msg); return send_rll_simple(RSL_MT_REL_IND, &dl->mctx); @@ -1809,67 +801,41 @@ static int rslms_rx_rll_est_req(struct msgb *msg, struct lapdm_datalink *dl) /* transmit a SABM command with the P bit set to "1". The SABM * command shall contain the layer 3 message unit */ length = TLVP_LEN(&tv, RSL_IE_L3_INFO); - LOGP(DLLAPDM, LOGL_INFO, "perform establishment with content " - "(SABM)\n"); } else { /* normal establishment procedure */ + msg->l3h = msg->l2h + sizeof(*rllh); length = 0; - LOGP(DLLAPDM, LOGL_INFO, "perform normal establishm. (SABM)\n"); } /* check if the layer3 message length exceeds N201 */ if (length + 3 > 21) { /* FIXME: do we know the channel N201? */ - LOGP(DLLAPDM, LOGL_ERROR, "frame too large: %d > N201(%d) " + LOGP(DLLAPD, LOGL_ERROR, "frame too large: %d > N201(%d) " "(discarding)\n", length + 3, 21); msgb_free(msg); return send_rll_simple(RSL_MT_REL_IND, &dl->mctx); } - /* Flush send-queue */ - /* Clear send-buffer */ - lapdm_dl_flush_send(dl); - - /* Discard partly received L3 message */ - if (dl->rcv_buffer) { - msgb_free(dl->rcv_buffer); - dl->rcv_buffer = NULL; - } - - /* Remove RLL header from msgb */ + /* Remove RLL header from msgb and set length to L3-info */ msgb_pull_l2h(msg); + msg->len = length; + msg->tail = msg->data + length; - /* Push LAPDm header on msgb */ - msg->l2h = msgb_push(msg, 3); - msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); - msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_SABM, 1); - msg->l2h[2] = LAPDm_LEN(length); - /* Transmit-buffer carries exactly one segment */ - memcpy(dl->tx_hist[0], msg->l2h, 3 + length); - dl->tx_length[0] = 3 + length; - /* set Vs to 0, because it is used as index when resending SABM */ - dl->V_send = 0; - - /* Set states */ - dl->own_busy = dl->peer_busy = 0; - dl->retrans_ctr = 0; - lapdm_dl_newstate(dl, LAPDm_STATE_SABM_SENT); - - /* Tramsmit and start T200 */ - osmo_timer_schedule(&dl->t200, T200); - return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, n201); + /* prepare prim */ + osmo_prim_init(&dp.oph, 0, PRIM_DL_EST, PRIM_OP_REQUEST, msg); + + /* send to L2 */ + return lapd_recv_dlsap(&dp, &dl->dl.lctx); } /* L3 requests transfer of unnumbered information */ static int rslms_rx_rll_udata_req(struct msgb *msg, struct lapdm_datalink *dl) { - struct lapdm_entity *le = dl->entity; struct abis_rsl_rll_hdr *rllh = msgb_l2(msg); uint8_t chan_nr = rllh->chan_nr; uint8_t link_id = rllh->link_id; uint8_t sapi = link_id & 7; struct tlv_parsed tv; int length; - uint8_t n201 = 23; //FIXME uint8_t ta = 0, tx_power = 0; /* check if the layer3 message length exceeds N201 */ @@ -1883,38 +849,40 @@ static int rslms_rx_rll_udata_req(struct msgb *msg, struct lapdm_datalink *dl) tx_power = *TLVP_VAL(&tv, RSL_IE_MS_POWER); } if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) { - LOGP(DLLAPDM, LOGL_ERROR, "unit data request without message " + LOGP(DLLAPD, LOGL_ERROR, "unit data request without message " "error\n"); msgb_free(msg); return -EINVAL; } - msg->l3h = TLVP_VAL(&tv, RSL_IE_L3_INFO); + msg->l3h = (uint8_t *) TLVP_VAL(&tv, RSL_IE_L3_INFO); length = TLVP_LEN(&tv, RSL_IE_L3_INFO); /* check if the layer3 message length exceeds N201 */ if (length + 5 > 23) { /* FIXME: do we know the channel N201? */ - LOGP(DLLAPDM, LOGL_ERROR, "frame too large: %d > N201(%d) " + LOGP(DLLAPD, LOGL_ERROR, "frame too large: %d > N201(%d) " "(discarding)\n", length + 5, 23); msgb_free(msg); return -EIO; } - LOGP(DLLAPDM, LOGL_INFO, "sending unit data (tx_power=%d, ta=%d)\n", + LOGP(DLLAPD, LOGL_INFO, "sending unit data (tx_power=%d, ta=%d)\n", tx_power, ta); - /* Remove RLL header from msgb */ + /* Remove RLL header from msgb and set length to L3-info */ msgb_pull_l2h(msg); + msg->len = length; + msg->tail = msg->data + length; /* Push L1 + LAPDm header on msgb */ msg->l2h = msgb_push(msg, 2 + 3); msg->l2h[0] = tx_power; msg->l2h[1] = ta; - msg->l2h[2] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); + msg->l2h[2] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, dl->dl.cr.loc2rem.cmd); msg->l2h[3] = LAPDm_CTRL_U(LAPDm_U_UI, 0); msg->l2h[4] = LAPDm_LEN(length); // FIXME: short L2 header support /* Tramsmit */ - return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, n201); + return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, 23); } /* L3 requests transfer of acknowledged information */ @@ -1922,143 +890,29 @@ static int rslms_rx_rll_data_req(struct msgb *msg, struct lapdm_datalink *dl) { struct abis_rsl_rll_hdr *rllh = msgb_l2(msg); struct tlv_parsed tv; + int length; + struct osmo_dlsap_prim dp; rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh)); if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) { - LOGP(DLLAPDM, LOGL_ERROR, "data request without message " + LOGP(DLLAPD, LOGL_ERROR, "data request without message " "error\n"); msgb_free(msg); return -EINVAL; } - msg->l3h = TLVP_VAL(&tv, RSL_IE_L3_INFO); - - LOGP(DLLAPDM, LOGL_INFO, "writing message to send-queue\n"); + msg->l3h = (uint8_t *) TLVP_VAL(&tv, RSL_IE_L3_INFO); + length = TLVP_LEN(&tv, RSL_IE_L3_INFO); - /* Remove the RSL/RLL header */ + /* Remove RLL header from msgb and set length to L3-info */ msgb_pull_l2h(msg); + msg->len = length; + msg->tail = msg->data + length; - /* Write data into the send queue */ - msgb_enqueue(&dl->send_queue, msg); - - /* Send message, if possible */ - rslms_send_i(&dl->mctx, __LINE__); - return 0; -} - -/* Send next I frame from queued/buffered data */ -static int rslms_send_i(struct lapdm_msg_ctx *mctx, int line) -{ - struct lapdm_datalink *dl = mctx->dl; - struct lapdm_entity *le = dl->entity; - uint8_t chan_nr = mctx->chan_nr; - uint8_t link_id = mctx->link_id; - uint8_t sapi = link_id & 7; - int k = k_sapi[sapi]; - struct msgb *msg; - int length, left; - int rc = - 1; /* we sent nothing */ - - LOGP(DLLAPDM, LOGL_INFO, "%s() called from line %d\n", __func__, line); - - next_frame: - - if (dl->peer_busy) { - LOGP(DLLAPDM, LOGL_INFO, "peer busy, not sending\n"); - return rc; - } - - if (dl->state == LAPDm_STATE_TIMER_RECOV) { - LOGP(DLLAPDM, LOGL_INFO, "timer recovery, not sending\n"); - return rc; - } - - /* If the send state variable V(S) is equal to V(A) plus k - * (where k is the maximum number of outstanding I frames - see - * subclause 5.8.4), the data link layer entity shall not transmit any - * new I frames, but shall retransmit an I frame as a result - * of the error recovery procedures as described in subclauses 5.5.4 and - * 5.5.7. */ - if (dl->V_send == add_mod8(dl->V_ack, k)) { - LOGP(DLLAPDM, LOGL_INFO, "k frames outstanding, not sending " - "more (k=%u V(S)=%u V(A)=%u)\n", k, dl->V_send, - dl->V_ack); - return rc; - } - - /* if we have no tx_hist yet, we create it */ - if (!dl->tx_length[dl->V_send]) { - /* Get next message into send-buffer, if any */ - if (!dl->send_buffer) { - next_message: - dl->send_out = 0; - dl->send_buffer = msgb_dequeue(&dl->send_queue); - /* No more data to be sent */ - if (!dl->send_buffer) - return rc; - LOGP(DLLAPDM, LOGL_INFO, "get message from " - "send-queue\n"); - } - - /* How much is left in the send-buffer? */ - left = msgb_l3len(dl->send_buffer) - dl->send_out; - /* Segment, if data exceeds N201 */ - length = left; - if (length > mctx->n201 - 3) - length = mctx->n201 - 3; - LOGP(DLLAPDM, LOGL_INFO, "msg-len %d sent %d left %d N201 %d " - "length %d first byte %02x\n", - msgb_l3len(dl->send_buffer), dl->send_out, left, - mctx->n201, length, dl->send_buffer->l3h[0]); - /* If message in send-buffer is completely sent */ - if (left == 0) { - msgb_free(dl->send_buffer); - dl->send_buffer = NULL; - goto next_message; - } - - LOGP(DLLAPDM, LOGL_INFO, "send I frame %sV(S)=%d\n", - (left > length) ? "segment " : "", dl->V_send); - - /* Create I frame (segment) and transmit-buffer content */ - msg = msgb_alloc_headroom(23+10, 10, "LAPDm I"); - msg->l2h = msgb_put(msg, 3 + length); - msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); - msg->l2h[1] = LAPDm_CTRL_I(dl->V_recv, dl->V_send, 0); - msg->l2h[2] = LAPDm_LEN(length); - if (left > length) - msg->l2h[2] |= LAPDm_MORE; - memcpy(msg->l2h + 3, dl->send_buffer->l3h + dl->send_out, - length); - memcpy(dl->tx_hist[dl->V_send], msg->l2h, 3 + length); - dl->tx_length[dl->V_send] = 3 + length; - /* Add length to track how much is already in the tx buffer */ - dl->send_out += length; - } else { - LOGP(DLLAPDM, LOGL_INFO, "resend I frame from tx buffer " - "V(S)=%d\n", dl->V_send); - - /* Create I frame (segment) from tx_hist */ - length = dl->tx_length[dl->V_send]; - msg = msgb_alloc_headroom(23+10, 10, "LAPDm I"); - msg->l2h = msgb_put(msg, length); - memcpy(msg->l2h, dl->tx_hist[dl->V_send], length); - msg->l2h[1] = LAPDm_CTRL_I(dl->V_recv, dl->V_send, 0); - } - - /* The value of the send state variable V(S) shall be incremented by 1 - * at the end of the transmission of the I frame */ - dl->V_send = inc_mod8(dl->V_send); - - /* If timer T200 is not running at the time right before transmitting a - * frame, when the PH-READY-TO-SEND primitive is received from the - * physical layer., it shall be set. */ - if (!osmo_timer_pending(&dl->t200)) - osmo_timer_schedule(&dl->t200, T200); + /* prepare prim */ + osmo_prim_init(&dp.oph, 0, PRIM_DL_DATA, PRIM_OP_REQUEST, msg); - tx_ph_data_enqueue(dl, msg, chan_nr, link_id, mctx->n201); - - rc = 0; /* we sent something */ - goto next_frame; + /* send to L2 */ + return lapd_recv_dlsap(&dp, &dl->dl.lctx); } /* L3 requests suspension of data link */ @@ -2066,165 +920,79 @@ static int rslms_rx_rll_susp_req(struct msgb *msg, struct lapdm_datalink *dl) { struct abis_rsl_rll_hdr *rllh = msgb_l2(msg); uint8_t sapi = rllh->link_id & 7; + struct osmo_dlsap_prim dp; if (sapi != 0) { - LOGP(DLLAPDM, LOGL_ERROR, "SAPI != 0 while suspending\n"); + LOGP(DLLAPD, LOGL_ERROR, "SAPI != 0 while suspending\n"); msgb_free(msg); return -EINVAL; } - LOGP(DLLAPDM, LOGL_INFO, "perform suspension\n"); - - /* put back the send-buffer to the send-queue (first position) */ - if (dl->send_buffer) { - LOGP(DLLAPDM, LOGL_INFO, "put frame in sendbuffer back to " - "queue\n"); - llist_add(&dl->send_buffer->list, &dl->send_queue); - dl->send_buffer = NULL; - } else - LOGP(DLLAPDM, LOGL_INFO, "no frame in sendbuffer\n"); - - /* Clear transmit buffer, but keep send buffer */ - lapdm_dl_flush_tx(dl); + /* prepare prim */ + osmo_prim_init(&dp.oph, 0, PRIM_DL_SUSP, PRIM_OP_REQUEST, msg); - msgb_free(msg); - - return send_rll_simple(RSL_MT_SUSP_CONF, &dl->mctx); + /* send to L2 */ + return lapd_recv_dlsap(&dp, &dl->dl.lctx); } /* L3 requests resume of data link */ static int rslms_rx_rll_res_req(struct msgb *msg, struct lapdm_datalink *dl) { - struct lapdm_entity *le = dl->entity; struct abis_rsl_rll_hdr *rllh = msgb_l2(msg); + int msg_type = rllh->c.msg_type; uint8_t chan_nr = rllh->chan_nr; uint8_t link_id = rllh->link_id; uint8_t sapi = rllh->link_id & 7; struct tlv_parsed tv; uint8_t length; - uint8_t n201 = 23; //FIXME + uint8_t n201 = 20; //FIXME + struct osmo_dlsap_prim dp; - /* Set chan_nr and link_id for established connection */ - memset(&dl->mctx, 0, sizeof(dl->mctx)); - dl->mctx.dl = dl; - dl->mctx.n201 = n201; - dl->mctx.chan_nr = chan_nr; - dl->mctx.link_id = link_id; + /* Set LAPDm context for established connection */ + set_lapdm_context(dl, chan_nr, link_id, n201, sapi); rsl_tlv_parse(&tv, rllh->data, msgb_l2len(msg)-sizeof(*rllh)); if (!TLVP_PRESENT(&tv, RSL_IE_L3_INFO)) { - LOGP(DLLAPDM, LOGL_ERROR, "resume without message error\n"); + LOGP(DLLAPD, LOGL_ERROR, "resume without message error\n"); msgb_free(msg); return send_rll_simple(RSL_MT_REL_IND, &dl->mctx); } + msg->l3h = (uint8_t *) TLVP_VAL(&tv, RSL_IE_L3_INFO); length = TLVP_LEN(&tv, RSL_IE_L3_INFO); - LOGP(DLLAPDM, LOGL_INFO, "perform re-establishment (SABM) length=%d\n", - length); - - /* Replace message in the send-buffer (reconnect) */ - if (dl->send_buffer) - msgb_free(dl->send_buffer); - dl->send_out = 0; - if (length) { - /* Remove the RSL/RLL header */ - msgb_pull_l2h(msg); - /* Write data into the send buffer, to be sent first */ - dl->send_buffer = msg; - } + /* Remove RLL header from msgb and set length to L3-info */ + msgb_pull_l2h(msg); + msg->len = length; + msg->tail = msg->data + length; - /* Discard partly received L3 message */ - if (dl->rcv_buffer) { - msgb_free(dl->rcv_buffer); - dl->rcv_buffer = NULL; - } + /* prepare prim */ + osmo_prim_init(&dp.oph, 0, (msg_type == RSL_MT_RES_REQ) ? PRIM_DL_RES + : PRIM_DL_RECON, PRIM_OP_REQUEST, msg); - /* Create new msgb (old one is now free) */ - msg = msgb_alloc_headroom(23+10, 10, "LAPDm SABM"); - msg->l2h = msgb_put(msg, 3); - msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); - msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_SABM, 1); - msg->l2h[2] = LAPDm_LEN(0); - /* Transmit-buffer carries exactly one segment */ - memcpy(dl->tx_hist[0], msg->l2h, 3); - dl->tx_length[0] = 3; - /* set Vs to 0, because it is used as index when resending SABM */ - dl->V_send = 0; - - /* Set states */ - dl->own_busy = dl->peer_busy = 0; - dl->retrans_ctr = 0; - lapdm_dl_newstate(dl, LAPDm_STATE_SABM_SENT); - - /* Tramsmit and start T200 */ - osmo_timer_schedule(&dl->t200, T200); - return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, n201); + /* send to L2 */ + return lapd_recv_dlsap(&dp, &dl->dl.lctx); } /* L3 requests release of data link */ static int rslms_rx_rll_rel_req(struct msgb *msg, struct lapdm_datalink *dl) { - struct lapdm_entity *le = dl->entity; struct abis_rsl_rll_hdr *rllh = msgb_l2(msg); - uint8_t chan_nr = rllh->chan_nr; - uint8_t link_id = rllh->link_id; - uint8_t sapi = rllh->link_id & 7; uint8_t mode = 0; + struct osmo_dlsap_prim dp; /* get release mode */ if (rllh->data[0] == RSL_IE_RELEASE_MODE) mode = rllh->data[1] & 1; - /* local release */ - if (mode) { - LOGP(DLLAPDM, LOGL_INFO, "perform local release\n"); - msgb_free(msg); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - /* enter idle state */ - lapdm_dl_newstate(dl, LAPDm_STATE_IDLE); - /* flush buffers */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); - /* send notification to L3 */ - return send_rll_simple(RSL_MT_REL_CONF, &dl->mctx); - } - - /* in case we are already disconnecting */ - if (dl->state == LAPDm_STATE_DISC_SENT) - return -EBUSY; - - LOGP(DLLAPDM, LOGL_INFO, "perform normal release (DISC)\n"); - /* Pull rllh */ msgb_pull(msg, msg->tail - msg->l2h); - /* Push LAPDm header on msgb */ - msg->l2h = msgb_push(msg, 3); - msg->l2h[0] = LAPDm_ADDR(LAPDm_LPD_NORMAL, sapi, le->cr.loc2rem.cmd); - msg->l2h[1] = LAPDm_CTRL_U(LAPDm_U_DISC, 1); - msg->l2h[2] = LAPDm_LEN(0); - /* Transmit-buffer carries exactly one segment */ - memcpy(dl->tx_hist[0], msg->l2h, 3); - dl->tx_length[0] = 3; - - /* Set states */ - dl->own_busy = dl->peer_busy = 0; - dl->retrans_ctr = 0; - lapdm_dl_newstate(dl, LAPDm_STATE_DISC_SENT); - - /* Tramsmit and start T200 */ - osmo_timer_schedule(&dl->t200, T200); - return tx_ph_data_enqueue(dl, msg, chan_nr, link_id, dl->mctx.n201); -} - -/* L3 requests release in idle state */ -static int rslms_rx_rll_rel_req_idle(struct msgb *msg, struct lapdm_datalink *dl) -{ - msgb_free(msg); + /* prepare prim */ + osmo_prim_init(&dp.oph, 0, PRIM_DL_REL, PRIM_OP_REQUEST, msg); + dp.u.rel_req.mode = mode; - /* send notification to L3 */ - return send_rll_simple(RSL_MT_REL_CONF, &dl->mctx); + /* send to L2 */ + return lapd_recv_dlsap(&dp, &dl->dl.lctx); } /* L3 requests channel in idle state */ @@ -2238,11 +1006,11 @@ static int rslms_rx_chan_rqd(struct lapdm_channel *lc, struct msgb *msg) PRIM_OP_REQUEST, NULL); if (msgb_l2len(msg) < sizeof(*cch) + 4 + 2 + 2) { - LOGP(DLLAPDM, LOGL_ERROR, "Message too short for CHAN RQD!\n"); + LOGP(DLLAPD, LOGL_ERROR, "Message too short for CHAN RQD!\n"); return -EINVAL; } if (cch->data[0] != RSL_IE_REQ_REFERENCE) { - LOGP(DLLAPDM, LOGL_ERROR, "Missing REQ REFERENCE IE\n"); + LOGP(DLLAPD, LOGL_ERROR, "Missing REQ REFERENCE IE\n"); return -EINVAL; } pp.u.rach_req.ra = cch->data[1]; @@ -2250,14 +1018,14 @@ static int rslms_rx_chan_rqd(struct lapdm_channel *lc, struct msgb *msg) pp.u.rach_req.is_combined_ccch = cch->data[2] >> 7; if (cch->data[4] != RSL_IE_ACCESS_DELAY) { - LOGP(DLLAPDM, LOGL_ERROR, "Missing ACCESS_DELAY IE\n"); + LOGP(DLLAPD, LOGL_ERROR, "Missing ACCESS_DELAY IE\n"); return -EINVAL; } /* TA = 0 - delay */ pp.u.rach_req.ta = 0 - cch->data[5]; if (cch->data[6] != RSL_IE_MS_POWER) { - LOGP(DLLAPDM, LOGL_ERROR, "Missing MS POWER IE\n"); + LOGP(DLLAPD, LOGL_ERROR, "Missing MS POWER IE\n"); return -EINVAL; } pp.u.rach_req.tx_power = cch->data[7]; @@ -2291,65 +1059,6 @@ static int l2_ph_chan_conf(struct msgb *msg, struct lapdm_entity *le, uint32_t f return rslms_sendmsg(msg, le); } -const char *lapdm_state_names[] = { - "LAPDm_STATE_NULL", - "LAPDm_STATE_IDLE", - "LAPDm_STATE_SABM_SENT", - "LAPDm_STATE_MF_EST", - "LAPDm_STATE_TIMER_RECOV", - "LAPDm_STATE_DISC_SENT", -}; - -/* statefull handling for RSLms RLL messages from L3 */ -static struct l2downstate { - uint32_t states; - int type; - int (*rout) (struct msgb *msg, struct lapdm_datalink *dl); -} l2downstatelist[] = { - /* create and send UI command */ - {ALL_STATES, - RSL_MT_UNIT_DATA_REQ, rslms_rx_rll_udata_req}, - - /* create and send SABM command */ - {SBIT(LAPDm_STATE_IDLE), - RSL_MT_EST_REQ, rslms_rx_rll_est_req}, - - /* create and send I command */ - {SBIT(LAPDm_STATE_MF_EST) | - SBIT(LAPDm_STATE_TIMER_RECOV), - RSL_MT_DATA_REQ, rslms_rx_rll_data_req}, - - /* suspend datalink */ - {SBIT(LAPDm_STATE_MF_EST) | - SBIT(LAPDm_STATE_TIMER_RECOV), - RSL_MT_SUSP_REQ, rslms_rx_rll_susp_req}, - - /* create and send SABM command (resume) */ - {SBIT(LAPDm_STATE_MF_EST) | - SBIT(LAPDm_STATE_TIMER_RECOV), - RSL_MT_RES_REQ, rslms_rx_rll_res_req}, - - /* create and send SABM command (reconnect) */ - {SBIT(LAPDm_STATE_IDLE) | - SBIT(LAPDm_STATE_MF_EST) | - SBIT(LAPDm_STATE_TIMER_RECOV), - RSL_MT_RECON_REQ, rslms_rx_rll_res_req}, - - /* create and send DISC command */ - {SBIT(LAPDm_STATE_SABM_SENT) | - SBIT(LAPDm_STATE_MF_EST) | - SBIT(LAPDm_STATE_TIMER_RECOV) | - SBIT(LAPDm_STATE_DISC_SENT), - RSL_MT_REL_REQ, rslms_rx_rll_rel_req}, - - /* release in idle state */ - {SBIT(LAPDm_STATE_IDLE), - RSL_MT_REL_REQ, rslms_rx_rll_rel_req_idle}, -}; - -#define L2DOWNSLLEN \ - (sizeof(l2downstatelist) / sizeof(struct l2downstate)) - /* incoming RSLms RLL message from L3 */ static int rslms_rx_rll(struct msgb *msg, struct lapdm_channel *lc) { @@ -2358,11 +1067,10 @@ static int rslms_rx_rll(struct msgb *msg, struct lapdm_channel *lc) uint8_t sapi = rllh->link_id & 7; struct lapdm_entity *le; struct lapdm_datalink *dl; - int i, supported = 0; int rc = 0; if (msgb_l2len(msg) < sizeof(*rllh)) { - LOGP(DLLAPDM, LOGL_ERROR, "Message too short for RLL hdr!\n"); + LOGP(DLLAPD, LOGL_ERROR, "Message too short for RLL hdr!\n"); return -EINVAL; } @@ -2376,34 +1084,41 @@ static int rslms_rx_rll(struct msgb *msg, struct lapdm_channel *lc) */ dl = datalink_for_sapi(le, sapi); if (!dl) { - LOGP(DLLAPDM, LOGL_ERROR, "No instance for SAPI %d!\n", sapi); + LOGP(DLLAPD, LOGL_ERROR, "No instance for SAPI %d!\n", sapi); return -EINVAL; } - LOGP(DLLAPDM, LOGL_INFO, "(%p) RLL Message '%s' received in state %s\n", - lc->name, rsl_msg_name(msg_type), lapdm_state_names[dl->state]); + LOGP(DLLAPD, LOGL_INFO, "(%p) RLL Message '%s' received.\n", + lc->name, rsl_msg_name(msg_type)); - /* find function for current state and message */ - for (i = 0; i < L2DOWNSLLEN; i++) { - if (msg_type == l2downstatelist[i].type) - supported = 1; - if ((msg_type == l2downstatelist[i].type) - && ((1 << dl->state) & l2downstatelist[i].states)) - break; - } - if (!supported) { - LOGP(DLLAPDM, LOGL_NOTICE, "Message unsupported.\n"); - msgb_free(msg); - return 0; - } - if (i == L2DOWNSLLEN) { - LOGP(DLLAPDM, LOGL_NOTICE, "Message unhandled at this state.\n"); + switch (msg_type) { + case RSL_MT_UNIT_DATA_REQ: + rc = rslms_rx_rll_udata_req(msg, dl); + break; + case RSL_MT_EST_REQ: + rc = rslms_rx_rll_est_req(msg, dl); + break; + case RSL_MT_DATA_REQ: + rc = rslms_rx_rll_data_req(msg, dl); + break; + case RSL_MT_SUSP_REQ: + rc = rslms_rx_rll_susp_req(msg, dl); + break; + case RSL_MT_RES_REQ: + rc = rslms_rx_rll_res_req(msg, dl); + break; + case RSL_MT_RECON_REQ: + rc = rslms_rx_rll_res_req(msg, dl); + break; + case RSL_MT_REL_REQ: + rc = rslms_rx_rll_rel_req(msg, dl); + break; + default: + LOGP(DLLAPD, LOGL_NOTICE, "Message unsupported.\n"); msgb_free(msg); - return 0; + rc = -EINVAL; } - rc = l2downstatelist[i].rout(msg, dl); - return rc; } @@ -2415,7 +1130,7 @@ static int rslms_rx_com_chan(struct msgb *msg, struct lapdm_channel *lc) int rc = 0; if (msgb_l2len(msg) < sizeof(*cch)) { - LOGP(DLLAPDM, LOGL_ERROR, "Message too short for COM CHAN hdr!\n"); + LOGP(DLLAPD, LOGL_ERROR, "Message too short for COM CHAN hdr!\n"); return -EINVAL; } @@ -2425,7 +1140,7 @@ static int rslms_rx_com_chan(struct msgb *msg, struct lapdm_channel *lc) rc = rslms_rx_chan_rqd(lc, msg); break; default: - LOGP(DLLAPDM, LOGL_NOTICE, "Unknown COMMON CHANNEL msg %d!\n", + LOGP(DLLAPD, LOGL_NOTICE, "Unknown COMMON CHANNEL msg %d!\n", msg_type); msgb_free(msg); return 0; @@ -2441,7 +1156,7 @@ int lapdm_rslms_recvmsg(struct msgb *msg, struct lapdm_channel *lc) int rc = 0; if (msgb_l2len(msg) < sizeof(*rslh)) { - LOGP(DLLAPDM, LOGL_ERROR, "Message too short RSL hdr!\n"); + LOGP(DLLAPD, LOGL_ERROR, "Message too short RSL hdr!\n"); return -EINVAL; } @@ -2453,7 +1168,7 @@ int lapdm_rslms_recvmsg(struct msgb *msg, struct lapdm_channel *lc) rc = rslms_rx_com_chan(msg, lc); break; default: - LOGP(DLLAPDM, LOGL_ERROR, "unknown RSLms message " + LOGP(DLLAPD, LOGL_ERROR, "unknown RSLms message " "discriminator 0x%02x", rslh->msg_discr); msgb_free(msg); return -EINVAL; @@ -2465,23 +1180,24 @@ int lapdm_rslms_recvmsg(struct msgb *msg, struct lapdm_channel *lc) /*! \brief Set the \ref lapdm_mode of a LAPDm entity */ int lapdm_entity_set_mode(struct lapdm_entity *le, enum lapdm_mode mode) { + int i; + enum lapd_mode lm; + switch (mode) { case LAPDM_MODE_MS: - le->cr.loc2rem.cmd = CR_MS2BS_CMD; - le->cr.loc2rem.resp = CR_MS2BS_RESP; - le->cr.rem2loc.cmd = CR_BS2MS_CMD; - le->cr.rem2loc.resp = CR_BS2MS_RESP; + lm = LAPD_MODE_USER; break; case LAPDM_MODE_BTS: - le->cr.loc2rem.cmd = CR_BS2MS_CMD; - le->cr.loc2rem.resp = CR_BS2MS_RESP; - le->cr.rem2loc.cmd = CR_MS2BS_CMD; - le->cr.rem2loc.resp = CR_MS2BS_RESP; + lm = LAPD_MODE_NETWORK; break; default: return -EINVAL; } + for (i = 0; i < ARRAY_SIZE(le->datalink); i++) { + lapd_set_mode(&le->datalink[i].dl, lm); + } + le->mode = mode; return 0; @@ -2525,16 +1241,7 @@ void lapdm_entity_reset(struct lapdm_entity *le) for (i = 0; i < ARRAY_SIZE(le->datalink); i++) { dl = &le->datalink[i]; - if (dl->state == LAPDm_STATE_IDLE) - continue; - LOGP(DLLAPDM, LOGL_INFO, "Resetting LAPDm instance\n"); - /* reset Timer T200 */ - osmo_timer_del(&dl->t200); - /* enter idle state */ - dl->state = LAPDm_STATE_IDLE; - /* flush buffer */ - lapdm_dl_flush_tx(dl); - lapdm_dl_flush_send(dl); + lapd_dl_reset(&dl->dl); } } |