diff options
Diffstat (limited to 'src/gb/frame_relay.c')
-rw-r--r-- | src/gb/frame_relay.c | 1051 |
1 files changed, 1051 insertions, 0 deletions
diff --git a/src/gb/frame_relay.c b/src/gb/frame_relay.c new file mode 100644 index 00000000..e973b915 --- /dev/null +++ b/src/gb/frame_relay.c @@ -0,0 +1,1051 @@ +/*! \file frame_relay.c + * Implement frame relay/PVC by Q.933 + */ +/* (C) 2020 Harald Welte <laforge@gnumonks.org> + * (C) 2020 sysmocom - s.f.m.c. GmbH + * Author: Alexander Couzens <lynxis@fe80.eu> + * + * All Rights Reserved + * + * SPDX-License-Identifier: GPL-2.0+ + * + * 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, see <http://www.gnu.org/licenses/>. + * + */ + +#include <stdint.h> +#include <stdbool.h> +#include <unistd.h> +#include <errno.h> + +#include <osmocom/gprs/frame_relay.h> +#include <osmocom/core/endian.h> +#include <osmocom/core/utils.h> +#include <osmocom/core/logging.h> +#include <osmocom/core/linuxlist.h> +#include <osmocom/core/tdef.h> +#include <osmocom/core/timer.h> +#include <osmocom/core/msgb.h> + +#include <osmocom/gsm/tlv.h> + +#define LOGPFRL(frl, lvl, fmt, args ...) \ + LOGP(DFR, lvl, "%s: " fmt, (frl)->name, ## args) + +#define DFR DLNS + +/* Table 4-2/Q.931 */ +enum q931_msgtype { + /* Call establishment message */ + Q931_MSGT_ALERTING = 0x01, + Q931_MSGT_CALL_PROCEEDING = 0x02, + Q931_MSGT_CONNECT = 0x07, + Q931_MSGT_CONNECT_ACK = 0x0f, + Q931_MSGT_PROGRESS = 0x03, + Q931_MSGT_SETUP = 0x05, + Q931_MSGT_SETUP_ACK = 0x0d, + /* Call information phase message */ + Q931_MSGT_RESUME = 0x26, + Q931_MSGT_RESUME_ACK = 0x2e, + Q931_MSGT_RESUME_REJ = 0x22, + Q931_MSGT_SUSPEND = 0x25, + Q931_MSGT_SUSPEND_ACK = 0x2d, + Q931_MSGT_USER_INFO = 0x20, + /* Call clearing message */ + Q931_MSGT_DISCONNECT = 0x45, + Q931_MSGT_RELEASE = 0x4d, + Q931_MSGT_RELEASE_COMPLETE = 0x5a, + Q931_MSGT_RESTART = 0x46, + Q931_MSGT_RESTART_ACK = 0x4e, + /* Miscellaneous messages */ + Q931_MSGT_SEGMENT = 0x60, + Q931_MSGT_CONGESTION_CONTROL = 0x79, + Q931_MSGT_IFORMATION = 0x7b, + Q931_MSGT_NOTIFY = 0x6e, + Q931_MSGT_STATUS = 0x7d, + Q931_MSGT_STATUS_ENQUIRY = 0x75, +}; + + +/* Figure A.1/Q.933 Report type information element */ +enum q933_type_of_report { + Q933_REPT_FULL_STATUS = 0x00, + Q933_REPT_LINK_INTEGRITY_VERIF = 0x01, + Q933_REPT_SINGLE_PVC_ASYNC_STS = 0x02, +}; + +/* Q.933 Section A.3 */ +enum q933_iei { + Q933_IEI_REPORT_TYPE = 0x51, + Q933_IEI_LINK_INT_VERIF = 0x53, + Q933_IEI_PVC_STATUS = 0x57, +}; + +/* Q.933 Section A.3.3 */ +enum q933_pvc_status { + Q933_PVC_STATUS_DLC_ACTIVE = 0x02, + Q933_PVC_STATUS_DLC_DELETE = 0x04, + Q933_PVC_STATUS_DLC_NEW = 0x08, +}; + + + +#define LAPF_UI 0x03 /* UI control word */ +#define Q931_PDISC_CC 0x08 /* protocol discriminator */ +#define LMI_Q933A_CALLREF 0x00 /* NULL call-ref */ + +/* LMI DLCI values */ +#define LMI_Q933A_DLCI 0 /* Q.933A DLCI */ +#define LMI_CISCO_DLCI 1023 /* Cisco DLCI */ + +/* maximum of supported */ +#define MAX_SUPPORTED_PVC 10 + +/* TODO: add counters since good connection */ + +/* Message header of the L3 payload of a Q.933 Annex A message */ +struct q933_a_hdr { + uint8_t prot_disc; + uint8_t call_ref; + uint8_t msg_type; +} __attribute__((packed)); + +/* Value part of the Q.933 Annex A.3.3 IE */ +struct q933_a_pvc_sts { +#if OSMO_IS_LITTLE_ENDIAN + uint8_t dlci_msb:6, + spare:1, + ext0:1; + uint8_t space1:3, + dlci_lsb:4, + ext1:1; + uint8_t reserved:1, + active:1, + delete:1, + new:1, + spare2:3, + ext2:1; + +#elif OSMO_IS_BIG_ENDIAN +/* auto-generated from the little endian part above (libosmocore/contrib/struct_endianness.py) */ + uint8_t ext0:1, spare:1, dlci_msb:6; + uint8_t ext1:1, dlci_lsb:4, space1:3; + uint8_t ext2:1, spare2:3, new:1, delete:1, active:1, reserved:1; +#endif +} __attribute__((packed)); + +/* RX Message: 14 [ 00 01 03 08 00 75 95 01 01 00 03 02 01 00 ] */ +/* RX Message: 13 [ 00 01 03 08 00 75 51 01 00 53 02 01 00 ] */ + +const struct value_string osmo_fr_role_names[] = { + { FR_ROLE_USER_EQUIPMENT, "USER" }, + { FR_ROLE_NETWORK_EQUIPMENT, "NETWORK" }, + { 0, NULL } +}; + +/* Table A.4/Q.933 */ +struct osmo_tdef fr_tdefs[] = { + { + .T=391, + .default_val = 10, + .min_val = 5, + .max_val = 30, + .desc = "Link integrity verification polling timer", + .unit = OSMO_TDEF_S, + }, { + .T=392, + .default_val = 15, + .min_val = 5, + .max_val = 30, + .desc = "Polling verification timer", + .unit = OSMO_TDEF_S, + }, + {} +}; + +static const struct tlv_definition q933_att_tlvdef = { + .def = { + [Q933_IEI_REPORT_TYPE] = { TLV_TYPE_TLV }, + [Q933_IEI_LINK_INT_VERIF] = { TLV_TYPE_TLV }, + [Q933_IEI_PVC_STATUS] = { TLV_TYPE_TLV }, + }, +}; + +static void check_link_state(struct osmo_fr_link *link, bool valid); + +static inline uint16_t q922_to_dlci(const uint8_t *hdr) +{ + return ((hdr[0] & 0xFC) << 2) | ((hdr[1] & 0xF0) >> 4); +} + + +static inline void dlci_to_q922(uint8_t *hdr, uint16_t dlci) +{ + hdr[0] = (dlci >> 2) & 0xFC; + hdr[1] = ((dlci << 4) & 0xF0) | 0x01; +} + +static void dlc_set_active(struct osmo_fr_dlc *dlc, bool active) +{ + if (active == dlc->active) + return; + + dlc->active = active; + + LOGPFRL(dlc->link, LOGL_NOTICE, "DLCI %u became %s\n", dlc->dlci, active ? "active" : "inactive"); + if (dlc->status_cb) + dlc->status_cb(dlc, dlc->cb_data, active); +} + +/* allocate a message buffer and put Q.933 Annex A headers (L2 + L3) */ +static struct msgb *q933_msgb_alloc(uint16_t dlci, uint8_t prot_disc, uint8_t msg_type) +{ + struct msgb *msg = msgb_alloc_headroom(1600+64, 64, "FR Q.933 Tx"); + struct q933_a_hdr *qh; + + if (!msg) + return NULL; + + msg->l1h = msgb_put(msg, 2); + dlci_to_q922(msg->l1h, dlci); + + /* LAPF UI control */ + msg->l2h = msgb_put(msg, 1); + *msg->l2h = LAPF_UI; + + msg->l3h = msgb_put(msg, sizeof(*qh)); + qh = (struct q933_a_hdr *) msg->l3h; + qh->prot_disc = prot_disc; + qh->call_ref = LMI_Q933A_CALLREF; + qh->msg_type = msg_type; + + return msg; +} + +/* obtain the [next] transmit sequence number */ +static uint8_t link_get_tx_seq(struct osmo_fr_link *link) +{ + /* The {user equipment, network} increments the send sequence + * counter using modulo 256. The value zero is skipped. */ + link->last_tx_seq++; + if (link->last_tx_seq == 0) + link->last_tx_seq++; + + return link->last_tx_seq; +} + +/* Append PVC Status IE according to Q.933 A.3.2 */ +static void msgb_put_link_int_verif(struct msgb *msg, struct osmo_fr_link *link) +{ + uint8_t link_int_tx[2]; + link_int_tx[0] = link_get_tx_seq(link); + link_int_tx[1] = link->last_rx_seq; + msgb_tlv_put(msg, Q933_IEI_LINK_INT_VERIF, 2, link_int_tx); +} + +static void dlc_destroy(struct osmo_fr_dlc *dlc) +{ + llist_del(&dlc->list); + talloc_free(dlc); +} + +/* Append PVC Status IE according to Q.933 A.3.3 */ +static void msgb_put_pvc_status(struct msgb *msg, struct osmo_fr_dlc *dlc) +{ + uint8_t ie[3]; + + ie[0] = (dlc->dlci >> 4) & 0x3f; + /* extension bits */ + ie[1] = 0x80 | ((dlc->dlci & 0xf) << 3); + /* extension bits */ + ie[2] = 0x80; + + /* FIXME: validate: this status should be added as long it's not yet acked by the remote */ + if (dlc->active) + ie[2] |= Q933_PVC_STATUS_DLC_ACTIVE; + + if (dlc->add) { + ie[2] |= Q933_PVC_STATUS_DLC_NEW; + /* we've reported it as new once, reset the status */ + } + + if (dlc->del) { + ie[2] |= Q933_PVC_STATUS_DLC_DELETE; + /* we've reported it as deleted once, destroy it */ + dlc_destroy(dlc); + } + + msgb_tlv_put(msg, Q933_IEI_PVC_STATUS, 3, ie); +} + +/* Send a Q.933 STATUS ENQUIRY given type over given link */ +static int tx_lmi_q933_status_enq(struct osmo_fr_link *link, uint8_t rep_type) +{ + struct msgb *resp; + + resp = q933_msgb_alloc(0, Q931_PDISC_CC, Q931_MSGT_STATUS_ENQUIRY); + if (!resp) + return -1; + resp->dst = link; + link->expected_rep = rep_type; + + /* Table A.2/Q.933 */ + msgb_tlv_put(resp, Q933_IEI_REPORT_TYPE, 1, &rep_type); + msgb_put_link_int_verif(resp, link); + + return link->tx_cb(link->cb_data, resp); +} + +/* Send a Q.933 STATUS of given type over given link */ +static int tx_lmi_q933_status(struct osmo_fr_link *link, uint8_t rep_type) +{ + struct osmo_fr_dlc *dlc; + struct msgb *resp; + + resp = q933_msgb_alloc(0, Q931_PDISC_CC, Q931_MSGT_STATUS); + if (!resp) + return -1; + + resp->dst = link; + + /* Table A.1/Q.933 */ + msgb_tlv_put(resp, Q933_IEI_REPORT_TYPE, 1, &rep_type); + switch (rep_type) { + case Q933_REPT_FULL_STATUS: + msgb_put_link_int_verif(resp, link); + llist_for_each_entry(dlc, &link->dlc_list, list) { + if (dlc->add || dlc->del) + dlc->state_send = true; + + msgb_put_pvc_status(resp, dlc); + } + break; + case Q933_REPT_LINK_INTEGRITY_VERIF: + msgb_put_link_int_verif(resp, link); + llist_for_each_entry(dlc, &link->dlc_list, list) { + if (dlc->add || dlc->del) { + msgb_put_pvc_status(resp, dlc); + dlc->state_send = true; + } + } + break; + case Q933_REPT_SINGLE_PVC_ASYNC_STS: + llist_for_each_entry(dlc, &link->dlc_list, list) + msgb_put_pvc_status(resp, dlc); + break; + } + + return link->tx_cb(link->cb_data, resp); +} + + +static void link_set_failed(struct osmo_fr_link *link) +{ + struct osmo_fr_dlc *dlc; + + LOGPFRL(link, LOGL_NOTICE, "Link failed\n"); + link->state = false; + if (link->status_cb) + link->status_cb(link, link->cb_data, link->state); + + llist_for_each_entry(dlc, &link->dlc_list, list) { + dlc_set_active(dlc, false); + } +} + +/* Q.933 */ +static int rx_lmi_q933_status_enq(struct msgb *msg, struct tlv_parsed *tp) +{ + struct osmo_fr_link *link = msg->dst; + struct osmo_fr_dlc *dlc; + const uint8_t *link_int_rx; + uint8_t rep_type; + + OSMO_ASSERT(link); + + if (link->role == FR_ROLE_USER_EQUIPMENT) { + LOGPFRL(link, LOGL_ERROR, "STATUS-ENQ aren't supported in role user\n"); + return -1; + } + + /* check for mandatory IEs */ + if (!TLVP_PRES_LEN(tp, Q933_IEI_REPORT_TYPE, 1) || + !TLVP_PRES_LEN(tp, Q933_IEI_LINK_INT_VERIF, 2)) + return -1; + + rep_type = *TLVP_VAL(tp, Q933_IEI_REPORT_TYPE); + + link_int_rx = TLVP_VAL(tp, Q933_IEI_LINK_INT_VERIF); + link->last_rx_seq = link_int_rx[0]; + + /* this is a bit of a hack. Q.933 explicitly forbids either side from ever + * sending a sequence number of '0'. Values start from '1' and are modulo 256, + * but '0' is always skipped. So if the peer is sending us a "last received + * sequence number of '0' it means it has not yet received any packets from us, + * which in turn can only mean that it has just been restarted. Let's treat + * this as "service affecting condition" and notify upper layers. This helps + * particularly in recovering from rapidly re-starting peers, where the Q.933 + * nor NS have time to actually detect the connection was lost. Se OS#4974 */ + if (link_int_rx[1] == 0) { + link_set_failed(link); + /* the network checks the receive sequence number received from + * the user equipment against its send sequence counter */ + } else if (link_int_rx[1] != link->last_tx_seq) { + check_link_state(link, false); + link->err_count++; + } else { + check_link_state(link, true); + /* confirm DLC state changes */ + llist_for_each_entry(dlc, &link->dlc_list, list) { + if (!dlc->state_send) + continue; + + if (dlc->add) { + dlc_set_active(dlc, link->state); + dlc->add = false; + } + + if (dlc->del) { + dlc->del = false; + } + + dlc->state_send = false; + } + } + + + /* The network responds to each STATUS ENQUIRY message with a + * STATUS message and resets the T392 timer */ + osmo_timer_schedule(&link->t392, osmo_tdef_get(link->net->T_defs, 392, OSMO_TDEF_S, 15), 0); + + return tx_lmi_q933_status(link, rep_type); +} + +/* check if the link become active. + * The link becomes active when enough times a STATUS/STATUS ENQUIRY arrives without any loss. + * Look at the last N393 STATUS/STATUS ENQUIRY PDUs. The link is valid if at least N392 + * got received. + * param[in] valid contains the status of the last packet */ +static void check_link_state(struct osmo_fr_link *link, bool valid) +{ + unsigned int last, i; + unsigned int carry = 0; + struct osmo_fr_dlc *dlc; + + link->succeed <<= 1; + if (valid) + link->succeed |= 1; + + /* count the bits */ + last = link->succeed & ((1 << link->net->n393) - 1); + for (i = 0; i < link->net->n393; i++) + if (last & (1 << i)) + carry++; + + if (link->net->n393 - carry >= link->net->n392) { + /* failing link */ + if (!link->state) + return; + + link_set_failed(link); + } else { + /* good link */ + if (link->state) + return; + + LOGPFRL(link, LOGL_NOTICE, "Link recovered\n"); + link->state = true; + if (link->status_cb) + link->status_cb(link, link->cb_data, link->state); + + if (link->role == FR_ROLE_USER_EQUIPMENT) { + /* make sure the next STATUS ENQUIRY is for a full + * status report to get the configred DLCs ASAP */ + link->polling_count = 0; + /* we must not proceed further below if we're in user role, + * as otherwise link recovery would set all DLCs as active */ + return; + } + + llist_for_each_entry(dlc, &link->dlc_list, list) { + if (!dlc->add && !dlc->del) + dlc_set_active(dlc, true); + } + } +} + +static int validate_pvc_status(struct tlv_parsed *tp, size_t tp_len) +{ + size_t i; + uint16_t len = 0; + + for (i = 0; i < tp_len; i++) { + if (!TLVP_PRESENT(&tp[i], Q933_IEI_PVC_STATUS)) + continue; + + /* PVC status can be 2 or 3 bytes. If the PVC is bigger + * ignore this to be compatible to future extensions. */ + len = TLVP_LEN(&tp[i], Q933_IEI_PVC_STATUS); + if (len <= 1) { + return -EINVAL; + } + /* FIXME: validate correct flags: are some flags invalid at the same time? */ + } + + return 0; +} + +static int parse_full_pvc_status(struct osmo_fr_link *link, struct tlv_parsed *tp, size_t tp_len) +{ + size_t i; + int err = 0; + struct osmo_fr_dlc *dlc, *tmp; + struct q933_a_pvc_sts *pvc; + uint16_t dlci = 0; + uint16_t *dlcis = talloc_zero_array(link, uint16_t, tp_len); + if (!dlcis) + return -ENOMEM; + + /* first run validate all PVCs */ + err = validate_pvc_status(tp, tp_len); + if (err < 0) + goto out; + + for (i = 0; i < tp_len; i++) { + if (!TLVP_PRESENT(&tp[i], Q933_IEI_PVC_STATUS)) + continue; + + /* parse only 3 byte PVCs */ + pvc = (struct q933_a_pvc_sts *) TLVP_VAL_MINLEN( + &tp[i], + Q933_IEI_PVC_STATUS, + sizeof(struct q933_a_pvc_sts)); + if (!pvc) + continue; + + dlci = ((pvc->dlci_msb & 0x3f) << 4) | (pvc->dlci_lsb & 0xf); + dlcis[i] = dlci; + dlc = osmo_fr_dlc_by_dlci(link, dlci); + if (!dlc) { + dlc = osmo_fr_dlc_alloc(link, dlci); + if (!dlc) { + LOGPFRL(link, LOGL_ERROR, "Could not create DLC %d\n", dlci); + continue; + } + } + + /* Figure A.3/Q.933: The delete bit is only applicable for timely notification + * using the optional single PVC asynchronous status report. + * Ignoring the delete. */ + dlc->add = pvc->new; + dlc_set_active(dlc, pvc->active); + dlc->del = 0; + } + + /* check if all dlc are present in PVC Status */ + llist_for_each_entry_safe(dlc, tmp, &link->dlc_list, list) { + bool found = false; + for (i = 0; i < tp_len; i++) { + if (dlcis[i] == dlc->dlci) { + found = true; + break; + } + } + + if (!found) { + dlc_set_active(dlc, false); + dlc->del = true; + } + } + + return 0; +out: + talloc_free(dlcis); + return err; +} + +static int parse_link_pvc_status(struct osmo_fr_link *link, struct tlv_parsed *tp, size_t tp_len) +{ + int err; + size_t i; + struct q933_a_pvc_sts *pvc; + struct osmo_fr_dlc *dlc; + uint16_t dlci = 0; + + err = validate_pvc_status(tp, tp_len); + if (err < 0) + return err; + + for (i = 0; i < tp_len; i++) { + if (!TLVP_PRESENT(&tp[i], Q933_IEI_PVC_STATUS)) + continue; + + /* parse only 3 byte PVCs */ + pvc = (struct q933_a_pvc_sts *) TLVP_VAL_MINLEN( + &tp[i], + Q933_IEI_PVC_STATUS, + sizeof(struct q933_a_pvc_sts)); + if (!pvc) + continue; + + dlci = ((pvc->dlci_msb & 0x3f) << 4) | (pvc->dlci_lsb & 0xf); + dlc = osmo_fr_dlc_by_dlci(link, dlci); + if (!dlc) { + /* don't create dlc's for the ones which are about to be deleted. */ + if (pvc->delete) + continue; + + dlc = osmo_fr_dlc_alloc(link, dlci); + if (!dlc) { + LOGPFRL(link, LOGL_ERROR, "Rx STATUS: Could not create DLC %d\n", dlci); + continue; + } + } + + if (pvc->delete) { + dlc->del = 1; + } else { + dlc->add = pvc->new; + dlc_set_active(dlc, pvc->active); + dlc->del = 0; + } + } + + return 0; +} + +static size_t count_pvc_status(struct tlv_parsed *tp, size_t tp_len) +{ + size_t i, count = 0; + for (i = 0; i < tp_len; i++) { + if (!TLVP_PRESENT(&tp[i], Q933_IEI_PVC_STATUS)) + continue; + count++; + } + + return count; +} + +static int rx_lmi_q933_status(struct msgb *msg, struct tlv_parsed *tp) +{ + struct osmo_fr_link *link = msg->dst; + const uint8_t *link_int_rx; + uint8_t rep_type; + + OSMO_ASSERT(link); + + if (link->role == FR_ROLE_NETWORK_EQUIPMENT) { + LOGPFRL(link, LOGL_ERROR, "Rx STATUS: STATUS aren't supported in role network\n"); + return -1; + } + + /* check for mandatory IEs */ + if (!TLVP_PRES_LEN(tp, Q933_IEI_REPORT_TYPE, 1)) { + LOGPFRL(link, LOGL_NOTICE, "Rx STATUS: Missing TLV Q933 Report Type\n"); + return -1; + } + + rep_type = *TLVP_VAL(tp, Q933_IEI_REPORT_TYPE); + + switch (rep_type) { + case Q933_REPT_FULL_STATUS: + case Q933_REPT_LINK_INTEGRITY_VERIF: + if (rep_type != link->expected_rep) { + LOGPFRL(link, LOGL_NOTICE, "Rx STATUS: Unexpected Q933 report type (got 0x%x != exp 0x%x)\n", + rep_type, link->expected_rep); + return -1; + } + + if (!TLVP_PRES_LEN(tp, Q933_IEI_LINK_INT_VERIF, 2)) { + LOGPFRL(link, LOGL_NOTICE, "Rx STATUS: Missing TLV Q933 Link Integrety Verification\n"); + return -1; + } + link_int_rx = TLVP_VAL(tp, Q933_IEI_LINK_INT_VERIF); + link->last_rx_seq = link_int_rx[0]; + /* The received receive sequence number is not valid if + * it is not equal to the last transmitted send sequence + * number. Ignore messages containing this error. As a + * result, timer T391 expires and the user then + * increments the error count. */ + if (link_int_rx[1] != link->last_tx_seq) + return 0; + break; + case Q933_REPT_SINGLE_PVC_ASYNC_STS: + default: + return -1; + } + + check_link_state(link, true); + if (count_pvc_status(tp, MAX_SUPPORTED_PVC + 1) > MAX_SUPPORTED_PVC) { + LOGPFRL(link, LOGL_ERROR, "Rx STATUS: Too many PVC! Only %d are supported!\n", MAX_SUPPORTED_PVC); + } + + switch (rep_type) { + case Q933_REPT_FULL_STATUS: + parse_full_pvc_status(link, tp, MAX_SUPPORTED_PVC); + break; + case Q933_REPT_LINK_INTEGRITY_VERIF: + parse_link_pvc_status(link, tp, MAX_SUPPORTED_PVC); + break; + default: + break; + } + + /* The network responds to each STATUS ENQUIRY message with a + * STATUS message and resets the T392 timer */ + osmo_timer_schedule(&link->t392, osmo_tdef_get(link->net->T_defs, 392, OSMO_TDEF_S, 15), 0); + + return 0; +} + +static int rx_lmi_q922(struct msgb *msg) +{ + struct osmo_fr_link *link = msg->dst; + struct q933_a_hdr *qh; + /* the + 1 is used to detect more than MAX_SUPPORTED_PVC */ + struct tlv_parsed tp[MAX_SUPPORTED_PVC + 1]; + uint8_t *lapf; + int rc; + + OSMO_ASSERT(link); + + if (msgb_l2len(msg) < 1) + return -1; + lapf = msgb_l2(msg); + + /* we only support LAPF UI frames */ + if (lapf[0] != LAPF_UI) + return -1; + + msg->l3h = msg->l2h + 1; + if (msgb_l3len(msg) < 3) + return -1; + + qh = (struct q933_a_hdr *) msgb_l3(msg); + if (qh->prot_disc != Q931_PDISC_CC) { + LOGPFRL(link, LOGL_NOTICE, + "Rx unsupported LMI protocol discriminator %u\n", qh->prot_disc); + return -1; + } + + rc = tlv_parse2(tp, MAX_SUPPORTED_PVC + 1, &q933_att_tlvdef, + msgb_l3(msg) + sizeof(*qh), + msgb_l3len(msg) - sizeof(*qh), 0, 0); + if (rc < 0) { + LOGPFRL(link, LOGL_NOTICE, + "Failed to parse TLVs in LMI message type %u\n", qh->msg_type); + return rc; + } + + switch (qh->msg_type) { + case Q931_MSGT_STATUS_ENQUIRY: + rc = rx_lmi_q933_status_enq(msg, tp); + break; + case Q931_MSGT_STATUS: + rc = rx_lmi_q933_status(msg, tp); + break; + default: + LOGPFRL(link, LOGL_NOTICE, + "Rx unsupported LMI message type %u\n", qh->msg_type); + rc = -1; + break; + } + msgb_free(msg); + + return rc; +} + +int osmo_fr_rx(struct msgb *msg) +{ + int rc = 0; + uint8_t *frh; + uint16_t dlci; + struct osmo_fr_dlc *dlc; + struct osmo_fr_link *link = msg->dst; + + OSMO_ASSERT(link); + + if (msgb_length(msg) < 2) { + LOGPFRL(link, LOGL_ERROR, "Rx short FR header: %u bytes\n", msgb_length(msg)); + rc = -1; + goto out; + } + + frh = msg->l1h = msgb_data(msg); + if (frh[0] & 0x01) { + LOGPFRL(link, LOGL_NOTICE, "Rx Unsupported single-byte FR address\n"); + rc = -1; + goto out; + } + if ((frh[1] & 0x0f) != 0x01) { + LOGPFRL(link, LOGL_NOTICE, "Rx Unknown second FR octet 0x%02x\n", frh[1]); + rc = -1; + goto out; + } + dlci = q922_to_dlci(frh); + msg->l2h = frh + 2; + + switch (dlci) { + case LMI_Q933A_DLCI: + return rx_lmi_q922(msg); + case LMI_CISCO_DLCI: + LOGPFRL(link, LOGL_ERROR, "Rx Unsupported FR DLCI %u\n", dlci); + goto out; + } + + if (!link->state) { + LOGPFRL(link, LOGL_NOTICE, "Link is not reliable. Discarding Rx PDU on DLCI %d\n", dlci); + goto out; + } + + dlc = osmo_fr_dlc_by_dlci(link, dlci); + if (dlc) { + if (dlc->active) { + /* dispatch to handler of respective DLC */ + msg->dst = dlc; + return dlc->rx_cb(dlc->cb_data, msg); + } else { + LOGPFRL(link, LOGL_NOTICE, "DLCI %u not yet active. Discarding Rx PDU\n", dlci); + } + } else { + if (link->unknown_dlc_rx_cb) + return link->unknown_dlc_rx_cb(link->unknown_dlc_rx_cb_data, msg); + else + LOGPFRL(link, LOGL_NOTICE, "DLCI %u doesn't exist. Discarding Rx PDU\n", dlci); + } + +out: + msgb_free(msg); + + return rc; +} + +int osmo_fr_tx_dlc(struct msgb *msg) +{ + uint8_t *frh; + struct osmo_fr_dlc *dlc = msg->dst; + struct osmo_fr_link *link = dlc->link; + + OSMO_ASSERT(dlc); + OSMO_ASSERT(link); + + if (!link->state) { + LOGPFRL(link, LOGL_NOTICE, "Link is not reliable (yet), discarding Tx\n"); + msgb_free(msg); + return -1; + } + if (!dlc->active) { + LOGPFRL(link, LOGL_NOTICE, "DLCI %u is not active (yet), discarding Tx\n", dlc->dlci); + msgb_free(msg); + return -1; + } + LOGPFRL(link, LOGL_DEBUG, "DLCI %u is active, sending message\n", dlc->dlci); + + if (msgb_headroom(msg) < 2) { + msgb_free(msg); + return -ENOSPC; + } + + frh = msgb_push(msg, 2); + dlci_to_q922(frh, dlc->dlci); + + msg->dst = link; + return link->tx_cb(link->cb_data, msg); +} + +/* Every T391 seconds, the user equipment sends a STATUS ENQUIRY + * message to the network and resets its polling timer (T391). */ +static void fr_t391_cb(void *data) +{ + struct osmo_fr_link *link = data; + + OSMO_ASSERT(link); + + if (link->polling_count % link->net->n391 == 0) + tx_lmi_q933_status_enq(link, Q933_REPT_FULL_STATUS); + else + tx_lmi_q933_status_enq(link, Q933_REPT_LINK_INTEGRITY_VERIF); + link->polling_count++; + osmo_timer_schedule(&link->t391, osmo_tdef_get(link->net->T_defs, 391, OSMO_TDEF_S, 10), 0); +} + +static void fr_t392_cb(void *data) +{ + struct osmo_fr_link *link = data; + + OSMO_ASSERT(link); + + /* A.5 The network increments the error count .. Non-receipt of + * a STATUS ENQUIRY within T392, which results in restarting + * T392 */ + link->err_count++; + check_link_state(link, false); + osmo_timer_schedule(&link->t392, osmo_tdef_get(link->net->T_defs, 392, OSMO_TDEF_S, 15), 0); +} + +/* allocate a frame relay network */ +struct osmo_fr_network *osmo_fr_network_alloc(void *ctx) +{ + struct osmo_fr_network *net = talloc_zero(ctx, struct osmo_fr_network); + if (!net) + return NULL; + + INIT_LLIST_HEAD(&net->links); + net->T_defs = fr_tdefs; + osmo_tdefs_reset(net->T_defs); + net->n391 = 6; + net->n392 = 3; + net->n393 = 4; + + return net; +} + +void osmo_fr_network_free(struct osmo_fr_network *net) +{ + struct osmo_fr_link *link, *tmp; + + if (!net) + return; + + llist_for_each_entry_safe(link, tmp, &net->links, list) { + osmo_fr_link_free(link); + } +} + +/* allocate a frame relay link in a given network */ +struct osmo_fr_link *osmo_fr_link_alloc(struct osmo_fr_network *net, enum osmo_fr_role role, const char *name) +{ + struct osmo_fr_link *link = talloc_zero(net, struct osmo_fr_link); + if (!link) + return NULL; + link->role = role; + link->net = net; + link->name = talloc_strdup(link, name); + INIT_LLIST_HEAD(&link->dlc_list); + llist_add_tail(&link->list, &net->links); + + osmo_timer_setup(&link->t391, fr_t391_cb, link); + osmo_timer_setup(&link->t392, fr_t392_cb, link); + + switch (role) { + case FR_ROLE_USER_EQUIPMENT: + osmo_timer_schedule(&link->t391, osmo_tdef_get(link->net->T_defs, 391, OSMO_TDEF_S, 15), 0); + break; + case FR_ROLE_NETWORK_EQUIPMENT: + osmo_timer_schedule(&link->t392, osmo_tdef_get(link->net->T_defs, 392, OSMO_TDEF_S, 15), 0); + break; + } + + LOGPFRL(link, LOGL_INFO, "Creating frame relay link with role %s\n", osmo_fr_role_str(role)); + + return link; +} + +void osmo_fr_link_free(struct osmo_fr_link *link) +{ + struct osmo_fr_dlc *dlc, *tmp; + + if (!link) + return; + + osmo_timer_del(&link->t391); + osmo_timer_del(&link->t392); + + llist_for_each_entry_safe(dlc, tmp, &link->dlc_list, list) { + osmo_fr_dlc_free(dlc); + } + + llist_del(&link->list); + talloc_free(link); +} + +/* allocate a data link connectoin on a given framerelay link */ +struct osmo_fr_dlc *osmo_fr_dlc_alloc(struct osmo_fr_link *link, uint16_t dlci) +{ + struct osmo_fr_dlc *dlc = talloc_zero(link, struct osmo_fr_dlc); + if (!dlc) + return NULL; + + dlc->link = link; + dlc->dlci = dlci; + dlc->active = false; + + llist_add_tail(&dlc->list, &link->dlc_list); + + dlc->add = true; + tx_lmi_q933_status(link, Q933_REPT_SINGLE_PVC_ASYNC_STS); + + return dlc; +} + +void osmo_fr_dlc_free(struct osmo_fr_dlc *dlc) +{ + llist_del(&dlc->list); + talloc_free(dlc); +} + +/* TODO: rework osmo_fr_dlc_alloc/free with handling it's own memory. + * For network role: The dlc have to created by the application (e.g. vty). + * The dlc shouldn't free'd directly. It should be communicated to the + * other side and wait until it's confirmed OR the link go off and free it afterwards. + * For user equpment role: The dlc can be created by the application or the dlc will be created + * by the frame relay because the network is configuring the dlc. + * The dlc shouldn't be free'd. Only the handler should be set to NULL. + */ + +struct osmo_fr_dlc *osmo_fr_dlc_by_dlci(struct osmo_fr_link *link, uint16_t dlci) +{ + struct osmo_fr_dlc *dlc; + + llist_for_each_entry(dlc, &link->dlc_list, list) { + if (dlc->dlci == dlci) + return dlc; + } + return NULL; +} + + +#include <osmocom/vty/vty.h> +#include <osmocom/vty/tdef_vty.h> + +static void fr_dlc_dump_vty(struct vty *vty, const struct osmo_fr_dlc *dlc) +{ + vty_out(vty, " FR DLC %05u: %s%s%s%s", dlc->dlci, + dlc->active ? "ACTIVE" : "INACTIVE", + dlc->add ? " ADDED" : "", dlc->del ? " DELETED" : "", VTY_NEWLINE); +} + +static void fr_link_dump_vty(struct vty *vty, const struct osmo_fr_link *link) +{ + const struct osmo_fr_dlc *dlc; + + vty_out(vty, "FR Link '%s': Role %s, LastRxSeq %u, LastTxSeq %u%s", + link->name, link->role == FR_ROLE_USER_EQUIPMENT ? "USER" : "NETWORK", + link->last_rx_seq, link->last_tx_seq, VTY_NEWLINE); + llist_for_each_entry(dlc, &link->dlc_list, list) { + fr_dlc_dump_vty(vty, dlc); + } +} + +void osmo_fr_network_dump_vty(struct vty *vty, const struct osmo_fr_network *net) +{ + struct osmo_fr_link *link; + + vty_out(vty, "FR Network: N391 %u, N392 %u, N393 %u%s", + net->n391, net->n392, net->n393, VTY_NEWLINE); + osmo_tdef_vty_out_all(vty, net->T_defs, " "); + llist_for_each_entry(link, &net->links, list) { + fr_link_dump_vty(vty, link); + } +} |