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-rw-r--r--src/gprs/gprs_llc.c852
1 files changed, 852 insertions, 0 deletions
diff --git a/src/gprs/gprs_llc.c b/src/gprs/gprs_llc.c
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index 000000000..7991f4c1e
--- /dev/null
+++ b/src/gprs/gprs_llc.c
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+/* GPRS LLC protocol implementation as per 3GPP TS 04.64 */
+
+/* (C) 2009-2010 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <errno.h>
+#include <stdint.h>
+
+#include <osmocore/msgb.h>
+#include <osmocore/linuxlist.h>
+#include <osmocore/timer.h>
+#include <osmocore/talloc.h>
+
+#include <openbsc/gsm_data.h>
+#include <openbsc/debug.h>
+#include <openbsc/gprs_sgsn.h>
+#include <openbsc/gprs_gmm.h>
+#include <openbsc/gprs_bssgp.h>
+#include <openbsc/gprs_llc.h>
+#include <openbsc/crc24.h>
+
+/* Section 8.9.9 LLC layer parameter default values */
+static const struct gprs_llc_params llc_default_params[] = {
+ [1] = {
+ .t200_201 = 5,
+ .n200 = 3,
+ .n201_u = 400,
+ },
+ [2] = {
+ .t200_201 = 5,
+ .n200 = 3,
+ .n201_u = 270,
+ },
+ [3] = {
+ .iov_i_exp = 27,
+ .t200_201 = 5,
+ .n200 = 3,
+ .n201_u = 500,
+ .n201_i = 1503,
+ .mD = 1520,
+ .mU = 1520,
+ .kD = 16,
+ .kU = 16,
+ },
+ [5] = {
+ .iov_i_exp = 27,
+ .t200_201 = 10,
+ .n200 = 3,
+ .n201_u = 500,
+ .n201_i = 1503,
+ .mD = 760,
+ .mU = 760,
+ .kD = 8,
+ .kU = 8,
+ },
+ [7] = {
+ .t200_201 = 20,
+ .n200 = 3,
+ .n201_u = 270,
+ },
+ [8] = {
+ .t200_201 = 20,
+ .n200 = 3,
+ .n201_u = 270,
+ },
+ [9] = {
+ .iov_i_exp = 27,
+ .t200_201 = 20,
+ .n200 = 3,
+ .n201_u = 500,
+ .n201_i = 1503,
+ .mD = 380,
+ .mU = 380,
+ .kD = 4,
+ .kU = 4,
+ },
+ [11] = {
+ .iov_i_exp = 27,
+ .t200_201 = 40,
+ .n200 = 3,
+ .n201_u = 500,
+ .n201_i = 1503,
+ .mD = 190,
+ .mU = 190,
+ .kD = 2,
+ .kU = 2,
+ },
+};
+
+LLIST_HEAD(gprs_llc_llmes);
+void *llc_tall_ctx;
+
+/* If the TLLI is foreign, return its local version */
+static inline uint32_t tlli_foreign2local(uint32_t tlli)
+{
+ uint32_t new_tlli;
+
+ if (gprs_tlli_type(tlli) == TLLI_FOREIGN) {
+ new_tlli = tlli | 0x40000000;
+ DEBUGP(DLLC, "TLLI 0x%08x is foreign, converting to "
+ "local TLLI 0x%08x\n", tlli, new_tlli);
+ } else
+ new_tlli = tlli;
+
+ return new_tlli;
+}
+
+/* lookup LLC Entity based on DLCI (TLLI+SAPI tuple) */
+static struct gprs_llc_lle *lle_by_tlli_sapi(uint32_t tlli, uint8_t sapi)
+{
+ struct gprs_llc_llme *llme;
+
+ tlli = tlli_foreign2local(tlli);
+
+ llist_for_each_entry(llme, &gprs_llc_llmes, list) {
+ if (llme->tlli == tlli || llme->old_tlli == tlli)
+ return &llme->lle[sapi];
+ }
+ return NULL;
+}
+
+static void lle_init(struct gprs_llc_llme *llme, uint8_t sapi)
+{
+ struct gprs_llc_lle *lle = &llme->lle[sapi];
+
+ lle->llme = llme;
+ lle->sapi = sapi;
+ lle->state = GPRS_LLES_UNASSIGNED;
+
+ /* Initialize according to parameters */
+ memcpy(&lle->params, &llc_default_params[sapi], sizeof(lle->params));
+}
+
+static struct gprs_llc_llme *llme_alloc(uint32_t tlli)
+{
+ struct gprs_llc_llme *llme;
+ uint32_t i;
+
+ llme = talloc_zero(llc_tall_ctx, struct gprs_llc_llme);
+ if (!llme)
+ return NULL;
+
+ llme->tlli = tlli;
+ llme->old_tlli = 0xffffffff;
+ llme->state = GPRS_LLMS_UNASSIGNED;
+
+ for (i = 0; i < ARRAY_SIZE(llme->lle); i++)
+ lle_init(llme, i);
+
+ llist_add(&llme->list, &gprs_llc_llmes);
+
+ return llme;
+}
+
+static void llme_free(struct gprs_llc_llme *llme)
+{
+ llist_del(&llme->list);
+ talloc_free(llme);
+}
+
+enum gprs_llc_cmd {
+ GPRS_LLC_NULL,
+ GPRS_LLC_RR,
+ GPRS_LLC_ACK,
+ GPRS_LLC_RNR,
+ GPRS_LLC_SACK,
+ GPRS_LLC_DM,
+ GPRS_LLC_DISC,
+ GPRS_LLC_UA,
+ GPRS_LLC_SABM,
+ GPRS_LLC_FRMR,
+ GPRS_LLC_XID,
+ GPRS_LLC_UI,
+};
+
+static const struct value_string llc_cmd_strs[] = {
+ { GPRS_LLC_NULL, "NULL" },
+ { GPRS_LLC_RR, "RR" },
+ { GPRS_LLC_ACK, "ACK" },
+ { GPRS_LLC_RNR, "RNR" },
+ { GPRS_LLC_SACK, "SACK" },
+ { GPRS_LLC_DM, "DM" },
+ { GPRS_LLC_DISC, "DISC" },
+ { GPRS_LLC_UA, "UA" },
+ { GPRS_LLC_SABM, "SABM" },
+ { GPRS_LLC_FRMR, "FRMR" },
+ { GPRS_LLC_XID, "XID" },
+ { GPRS_LLC_UI, "UI" },
+ { 0, NULL }
+};
+
+struct gprs_llc_hdr_parsed {
+ uint8_t sapi;
+ uint8_t is_cmd:1,
+ ack_req:1,
+ is_encrypted:1;
+ uint32_t seq_rx;
+ uint32_t seq_tx;
+ uint32_t fcs;
+ uint32_t fcs_calc;
+ uint8_t *data;
+ uint16_t data_len;
+ uint16_t crc_length;
+ enum gprs_llc_cmd cmd;
+};
+
+#define LLC_ALLOC_SIZE 16384
+#define UI_HDR_LEN 3
+#define N202 4
+#define CRC24_LENGTH 3
+
+static int gprs_llc_fcs(uint8_t *data, unsigned int len)
+{
+ uint32_t fcs_calc;
+
+ fcs_calc = crc24_calc(INIT_CRC24, data, len);
+ fcs_calc = ~fcs_calc;
+ fcs_calc &= 0xffffff;
+
+ return fcs_calc;
+}
+
+static void t200_expired(void *data)
+{
+ struct gprs_llc_lle *lle = data;
+
+ /* 8.5.1.3: Expiry of T200 */
+
+ if (lle->retrans_ctr >= lle->params.n200) {
+ /* FIXME: LLGM-STATUS-IND, LL-RELEASE-IND/CNF */
+ lle->state = GPRS_LLES_ASSIGNED_ADM;
+ }
+
+ switch (lle->state) {
+ case GPRS_LLES_LOCAL_EST:
+ /* FIXME: retransmit SABM */
+ /* FIXME: re-start T200 */
+ lle->retrans_ctr++;
+ break;
+ case GPRS_LLES_LOCAL_REL:
+ /* FIXME: retransmit DISC */
+ /* FIXME: re-start T200 */
+ lle->retrans_ctr++;
+ break;
+ }
+
+}
+
+static void t201_expired(void *data)
+{
+ struct gprs_llc_lle *lle = data;
+
+ if (lle->retrans_ctr < lle->params.n200) {
+ /* FIXME: transmit apropriate supervisory frame (8.6.4.1) */
+ /* FIXME: set timer T201 */
+ lle->retrans_ctr++;
+ }
+}
+
+int gprs_llc_tx_u(struct msgb *msg, uint8_t sapi, int command,
+ enum gprs_llc_u_cmd u_cmd, int pf_bit)
+{
+ uint8_t *fcs, *llch;
+ uint8_t addr, ctrl;
+ uint32_t fcs_calc;
+
+ /* Identifiers from UP: (TLLI, SAPI) + (BVCI, NSEI) */
+
+ /* Address Field */
+ addr = sapi & 0xf;
+ if (command)
+ addr |= 0x40;
+
+ /* 6.3 Figure 8 */
+ ctrl = 0xe0 | u_cmd;
+ if (pf_bit)
+ ctrl |= 0x10;
+
+ /* prepend LLC UI header */
+ llch = msgb_push(msg, 2);
+ llch[0] = addr;
+ llch[1] = ctrl;
+
+ /* append FCS to end of frame */
+ fcs = msgb_put(msg, 3);
+ fcs_calc = gprs_llc_fcs(llch, fcs - llch);
+ fcs[0] = fcs_calc & 0xff;
+ fcs[1] = (fcs_calc >> 8) & 0xff;
+ fcs[2] = (fcs_calc >> 16) & 0xff;
+
+ /* Identifiers passed down: (BVCI, NSEI) */
+
+ /* Send BSSGP-DL-UNITDATA.req */
+ return gprs_bssgp_tx_dl_ud(msg, NULL);
+}
+
+/* Send XID response to LLE */
+static int gprs_llc_tx_xid(struct gprs_llc_lle *lle, struct msgb *msg)
+{
+ /* copy identifiers from LLE to ensure lower layers can route */
+ msgb_tlli(msg) = lle->llme->tlli;
+ msgb_bvci(msg) = lle->llme->bvci;
+ msgb_nsei(msg) = lle->llme->nsei;
+
+ return gprs_llc_tx_u(msg, lle->sapi, 0, GPRS_LLC_U_XID, 1);
+}
+
+/* Transmit a UI frame over the given SAPI */
+int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command,
+ void *mmctx)
+{
+ struct gprs_llc_lle *lle;
+ uint8_t *fcs, *llch;
+ uint8_t addr, ctrl[2];
+ uint32_t fcs_calc;
+ uint16_t nu = 0;
+ uint32_t oc;
+
+ /* Identifiers from UP: (TLLI, SAPI) + (BVCI, NSEI) */
+
+ /* look-up or create the LL Entity for this (TLLI, SAPI) tuple */
+ lle = lle_by_tlli_sapi(msgb_tlli(msg), sapi);
+ if (!lle) {
+ struct gprs_llc_llme *llme;
+ LOGP(DLLC, LOGL_ERROR, "LLC TX: unknown TLLI 0x%08x, "
+ "creating LLME on the fly\n", msgb_tlli(msg));
+ llme = llme_alloc(msgb_tlli(msg));
+ lle = &llme->lle[sapi];
+ }
+
+ if (msg->len > lle->params.n201_u) {
+ LOGP(DLLC, LOGL_ERROR, "Cannot Tx %u bytes (N201-U=%u)\n",
+ msg->len, lle->params.n201_u);
+ return -EFBIG;
+ }
+
+ /* Update LLE's (BVCI, NSEI) tuple */
+ lle->llme->bvci = msgb_bvci(msg);
+ lle->llme->nsei = msgb_nsei(msg);
+
+ /* Obtain current values for N(u) and OC */
+ nu = lle->vu_send;
+ oc = lle->oc_ui_send;
+ /* Increment V(U) */
+ lle->vu_send = (lle->vu_send + 1) % 512;
+ /* Increment Overflow Counter, if needed */
+ if ((lle->vu_send + 1) / 512)
+ lle->oc_ui_send += 512;
+
+ /* Address Field */
+ addr = sapi & 0xf;
+ if (command)
+ addr |= 0x40;
+
+ /* Control Field */
+ ctrl[0] = 0xc0;
+ ctrl[0] |= nu >> 6;
+ ctrl[1] = (nu << 2) & 0xfc;
+ ctrl[1] |= 0x01; /* Protected Mode */
+
+ /* prepend LLC UI header */
+ llch = msgb_push(msg, 3);
+ llch[0] = addr;
+ llch[1] = ctrl[0];
+ llch[2] = ctrl[1];
+
+ /* append FCS to end of frame */
+ fcs = msgb_put(msg, 3);
+ fcs_calc = gprs_llc_fcs(llch, fcs - llch);
+ fcs[0] = fcs_calc & 0xff;
+ fcs[1] = (fcs_calc >> 8) & 0xff;
+ fcs[2] = (fcs_calc >> 16) & 0xff;
+
+ /* encrypt information field + FCS, if needed! */
+ if (lle->llme->algo != GPRS_ALGO_GEA0) {
+ uint32_t iov_ui = 0; /* FIXME: randomly select for TLLI */
+ uint16_t crypt_len = (fcs + 3) - (llch + 3);
+ uint8_t cipher_out[GSM0464_CIPH_MAX_BLOCK];
+ uint32_t iv;
+ int rc, i;
+ uint64_t kc = *(uint64_t *)&lle->llme->kc;
+
+ /* Compute the 'Input' Paraemeter */
+ iv = gprs_cipher_gen_input_ui(iov_ui, sapi, nu, oc);
+
+ /* Compute the keystream that we need to XOR with the data */
+ rc = gprs_cipher_run(cipher_out, crypt_len, lle->llme->algo,
+ kc, iv, GPRS_CIPH_SGSN2MS);
+ if (rc < 0) {
+ LOGP(DLLC, LOGL_ERROR, "Error crypting UI frame: %d\n", rc);
+ return rc;
+ }
+
+ /* XOR the cipher output with the information field + FCS */
+ for (i = 0; i < crypt_len; i++)
+ *(llch + 3 + i) ^= cipher_out[i];
+
+ /* Mark frame as encrypted */
+ ctrl[1] |= 0x02;
+ }
+
+ /* Identifiers passed down: (BVCI, NSEI) */
+
+ /* Send BSSGP-DL-UNITDATA.req */
+ return gprs_bssgp_tx_dl_ud(msg, mmctx);
+}
+
+static void gprs_llc_hdr_dump(struct gprs_llc_hdr_parsed *gph)
+{
+ DEBUGP(DLLC, "LLC SAPI=%u %c %c FCS=0x%06x",
+ gph->sapi, gph->is_cmd ? 'C' : 'R', gph->ack_req ? 'A' : ' ',
+ gph->fcs);
+
+ if (gph->cmd)
+ DEBUGPC(DLLC, "CMD=%s ", get_value_string(llc_cmd_strs, gph->cmd));
+
+ if (gph->data)
+ DEBUGPC(DLLC, "DATA ");
+
+ DEBUGPC(DLLC, "\n");
+}
+static int gprs_llc_hdr_rx(struct gprs_llc_hdr_parsed *gph,
+ struct gprs_llc_lle *lle)
+{
+ switch (gph->cmd) {
+ case GPRS_LLC_SABM: /* Section 6.4.1.1 */
+ lle->v_sent = lle->v_ack = lle->v_recv = 0;
+ if (lle->state == GPRS_LLES_ASSIGNED_ADM) {
+ /* start re-establishment (8.7.1) */
+ }
+ lle->state = GPRS_LLES_REMOTE_EST;
+ /* FIXME: Send UA */
+ lle->state = GPRS_LLES_ABM;
+ /* FIXME: process data */
+ break;
+ case GPRS_LLC_DISC: /* Section 6.4.1.2 */
+ /* FIXME: Send UA */
+ /* terminate ABM */
+ lle->state = GPRS_LLES_ASSIGNED_ADM;
+ break;
+ case GPRS_LLC_UA: /* Section 6.4.1.3 */
+ if (lle->state == GPRS_LLES_LOCAL_EST)
+ lle->state = GPRS_LLES_ABM;
+ break;
+ case GPRS_LLC_DM: /* Section 6.4.1.4: ABM cannot be performed */
+ if (lle->state == GPRS_LLES_LOCAL_EST)
+ lle->state = GPRS_LLES_ASSIGNED_ADM;
+ break;
+ case GPRS_LLC_FRMR: /* Section 6.4.1.5 */
+ break;
+ case GPRS_LLC_XID: /* Section 6.4.1.6 */
+ /* FIXME: implement XID negotiation using SNDCP */
+ {
+ struct msgb *resp;
+ uint8_t *xid;
+ resp = msgb_alloc_headroom(4096, 1024, "LLC_XID");
+ xid = msgb_put(resp, gph->data_len);
+ memcpy(xid, gph->data, gph->data_len);
+ gprs_llc_tx_xid(lle, resp);
+ }
+ break;
+ case GPRS_LLC_UI:
+ if (gph->seq_tx < lle->vu_recv) {
+ LOGP(DLLC, LOGL_NOTICE, "TLLI=%08x dropping UI, vurecv %u <= %u\n",
+ lle->llme ? lle->llme->tlli : -1,
+ gph->seq_tx, lle->vu_recv);
+ return -EIO;
+ }
+ /* Increment the sequence number that we expect in the next frame */
+ lle->vu_recv = (gph->seq_tx + 1) % 512;
+ /* Increment Overflow Counter */
+ if ((gph->seq_tx + 1) / 512)
+ lle->oc_ui_recv += 512;
+ break;
+ }
+
+ return 0;
+}
+
+/* parse a GPRS LLC header, also check for invalid frames */
+static int gprs_llc_hdr_parse(struct gprs_llc_hdr_parsed *ghp,
+ uint8_t *llc_hdr, int len)
+{
+ uint8_t *ctrl = llc_hdr+1;
+ int is_sack = 0;
+
+ if (len <= CRC24_LENGTH)
+ return -EIO;
+
+ ghp->crc_length = len - CRC24_LENGTH;
+
+ ghp->ack_req = 0;
+
+ /* Section 5.5: FCS */
+ ghp->fcs = *(llc_hdr + len - 3);
+ ghp->fcs |= *(llc_hdr + len - 2) << 8;
+ ghp->fcs |= *(llc_hdr + len - 1) << 16;
+
+ /* Section 6.2.1: invalid PD field */
+ if (llc_hdr[0] & 0x80)
+ return -EIO;
+
+ /* This only works for the MS->SGSN direction */
+ if (llc_hdr[0] & 0x40)
+ ghp->is_cmd = 0;
+ else
+ ghp->is_cmd = 1;
+
+ ghp->sapi = llc_hdr[0] & 0xf;
+
+ /* Section 6.2.3: check for reserved SAPI */
+ switch (ghp->sapi) {
+ case 0:
+ case 4:
+ case 6:
+ case 0xa:
+ case 0xc:
+ case 0xd:
+ case 0xf:
+ return -EINVAL;
+ }
+
+ if ((ctrl[0] & 0x80) == 0) {
+ /* I (Information transfer + Supervisory) format */
+ uint8_t k;
+
+ ghp->data = ctrl + 3;
+
+ if (ctrl[0] & 0x40)
+ ghp->ack_req = 1;
+
+ ghp->seq_tx = (ctrl[0] & 0x1f) << 4;
+ ghp->seq_tx |= (ctrl[1] >> 4);
+
+ ghp->seq_rx = (ctrl[1] & 0x7) << 6;
+ ghp->seq_rx |= (ctrl[2] >> 2);
+
+ switch (ctrl[2] & 0x03) {
+ case 0:
+ ghp->cmd = GPRS_LLC_RR;
+ break;
+ case 1:
+ ghp->cmd = GPRS_LLC_ACK;
+ break;
+ case 2:
+ ghp->cmd = GPRS_LLC_RNR;
+ break;
+ case 3:
+ ghp->cmd = GPRS_LLC_SACK;
+ k = ctrl[3] & 0x1f;
+ ghp->data += 1 + k;
+ break;
+ }
+ ghp->data_len = (llc_hdr + len - 3) - ghp->data;
+ } else if ((ctrl[0] & 0xc0) == 0x80) {
+ /* S (Supervisory) format */
+ ghp->data = NULL;
+ ghp->data_len = 0;
+
+ if (ctrl[0] & 0x20)
+ ghp->ack_req = 1;
+ ghp->seq_rx = (ctrl[0] & 0x7) << 6;
+ ghp->seq_rx |= (ctrl[1] >> 2);
+
+ switch (ctrl[1] & 0x03) {
+ case 0:
+ ghp->cmd = GPRS_LLC_RR;
+ break;
+ case 1:
+ ghp->cmd = GPRS_LLC_ACK;
+ break;
+ case 2:
+ ghp->cmd = GPRS_LLC_RNR;
+ break;
+ case 3:
+ ghp->cmd = GPRS_LLC_SACK;
+ break;
+ }
+ } else if ((ctrl[0] & 0xe0) == 0xc0) {
+ /* UI (Unconfirmed Inforamtion) format */
+ ghp->cmd = GPRS_LLC_UI;
+ ghp->data = ctrl + 2;
+ ghp->data_len = (llc_hdr + len - 3) - ghp->data;
+
+ ghp->seq_tx = (ctrl[0] & 0x7) << 6;
+ ghp->seq_tx |= (ctrl[1] >> 2);
+ if (ctrl[1] & 0x02) {
+ ghp->is_encrypted = 1;
+ /* FIXME: encryption */
+ }
+ if (ctrl[1] & 0x01) {
+ /* FCS over hdr + all inf fields */
+ } else {
+ /* FCS over hdr + N202 octets (4) */
+ if (ghp->crc_length > UI_HDR_LEN + N202)
+ ghp->crc_length = UI_HDR_LEN + N202;
+ }
+ } else {
+ /* U (Unnumbered) format: 1 1 1 P/F M4 M3 M2 M1 */
+ ghp->data = NULL;
+ ghp->data_len = 0;
+
+ switch (ctrl[0] & 0xf) {
+ case GPRS_LLC_U_NULL_CMD:
+ ghp->cmd = GPRS_LLC_NULL;
+ break;
+ case GPRS_LLC_U_DM_RESP:
+ ghp->cmd = GPRS_LLC_DM;
+ break;
+ case GPRS_LLC_U_DISC_CMD:
+ ghp->cmd = GPRS_LLC_DISC;
+ break;
+ case GPRS_LLC_U_UA_RESP:
+ ghp->cmd = GPRS_LLC_UA;
+ break;
+ case GPRS_LLC_U_SABM_CMD:
+ ghp->cmd = GPRS_LLC_SABM;
+ break;
+ case GPRS_LLC_U_FRMR_RESP:
+ ghp->cmd = GPRS_LLC_FRMR;
+ break;
+ case GPRS_LLC_U_XID:
+ ghp->cmd = GPRS_LLC_XID;
+ ghp->data = ctrl + 1;
+ ghp->data_len = (llc_hdr + len - 3) - ghp->data;
+ break;
+ default:
+ return -EIO;
+ }
+ }
+
+ /* FIXME: parse sack frame */
+ if (ghp->cmd == GPRS_LLC_SACK) {
+ LOGP(DLLC, LOGL_NOTICE, "Unsupported SACK frame\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/* receive an incoming LLC PDU (BSSGP-UL-UNITDATA-IND, 7.2.4.2) */
+int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv)
+{
+ struct bssgp_ud_hdr *udh = (struct bssgp_ud_hdr *) msgb_bssgph(msg);
+ struct gprs_llc_hdr *lh = msgb_llch(msg);
+ struct gprs_llc_hdr_parsed llhp;
+ struct gprs_llc_lle *lle;
+ int rc = 0;
+
+ /* Identifiers from DOWN: NSEI, BVCI, TLLI */
+
+ memset(&llhp, 0, sizeof(llhp));
+ rc = gprs_llc_hdr_parse(&llhp, (uint8_t *) lh, TLVP_LEN(tv, BSSGP_IE_LLC_PDU));
+ gprs_llc_hdr_dump(&llhp);
+ if (rc < 0) {
+ LOGP(DLLC, LOGL_NOTICE, "Error during LLC header parsing\n");
+ return rc;
+ }
+
+ switch (gprs_tlli_type(msgb_tlli(msg))) {
+ case TLLI_LOCAL:
+ case TLLI_FOREIGN:
+ case TLLI_RANDOM:
+ case TLLI_AUXILIARY:
+ break;
+ default:
+ LOGP(DLLC, LOGL_ERROR,
+ "Discarding frame with strange TLLI type\n");
+ break;
+ }
+
+ /* find the LLC Entity for this TLLI+SAPI tuple */
+ lle = lle_by_tlli_sapi(msgb_tlli(msg), llhp.sapi);
+
+ /* 7.2.1.1 LLC belonging to unassigned TLLI+SAPI shall be discarded,
+ * except UID and XID frames with SAPI=1 */
+ if (!lle) {
+ if (llhp.sapi == GPRS_SAPI_GMM &&
+ (llhp.cmd == GPRS_LLC_XID || llhp.cmd == GPRS_LLC_UI)) {
+ struct gprs_llc_llme *llme;
+ /* FIXME: don't use the TLLI but the 0xFFFF unassigned? */
+ llme = llme_alloc(msgb_tlli(msg));
+ LOGP(DLLC, LOGL_DEBUG, "LLC RX: unknown TLLI 0x08x, "
+ "creating LLME on the fly\n", msgb_tlli(msg));
+ lle = &llme->lle[llhp.sapi];
+ } else {
+ LOGP(DLLC, LOGL_NOTICE,
+ "unknown TLLI/SAPI: Silently dropping\n");
+ return 0;
+ }
+ }
+
+ /* decrypt information field + FCS, if needed! */
+ if (llhp.is_encrypted) {
+ uint32_t iov_ui = 0; /* FIXME: randomly select for TLLI */
+ uint16_t crypt_len = llhp.data_len + 3;
+ uint8_t cipher_out[GSM0464_CIPH_MAX_BLOCK];
+ uint32_t iv;
+ uint64_t kc = *(uint64_t *)&lle->llme->kc;
+ int rc, i;
+
+ if (lle->llme->algo == GPRS_ALGO_GEA0) {
+ LOGP(DLLC, LOGL_NOTICE, "encrypted frame for LLC that "
+ "has no KC/Algo! Dropping.\n");
+ return 0;
+ }
+
+ iv = gprs_cipher_gen_input_ui(iov_ui, lle->sapi, llhp.seq_tx,
+ lle->oc_ui_recv);
+ rc = gprs_cipher_run(cipher_out, crypt_len, lle->llme->algo,
+ kc, iv, GPRS_CIPH_MS2SGSN);
+ if (rc < 0) {
+ LOGP(DLLC, LOGL_ERROR, "Error decrypting frame: %d\n",
+ rc);
+ return rc;
+ }
+
+ /* XOR the cipher output with the information field + FCS */
+ for (i = 0; i < crypt_len; i++)
+ *(llhp.data + i) ^= cipher_out[i];
+ } else {
+ if (lle->llme->algo != GPRS_ALGO_GEA0) {
+ LOGP(DLLC, LOGL_NOTICE, "unencrypted frame for LLC "
+ "that is supposed to be encrypted. Dropping.\n");
+ return 0;
+ }
+ }
+
+ /* We have to do the FCS check _after_ decryption */
+ llhp.fcs_calc = gprs_llc_fcs((uint8_t *)lh, llhp.crc_length);
+ if (llhp.fcs != llhp.fcs_calc) {
+ LOGP(DLLC, LOGL_INFO, "Dropping frame with invalid FCS\n");
+ return -EIO;
+ }
+
+ /* Update LLE's (BVCI, NSEI) tuple */
+ lle->llme->bvci = msgb_bvci(msg);
+ lle->llme->nsei = msgb_nsei(msg);
+
+ /* Receive and Process the actual LLC frame */
+ rc = gprs_llc_hdr_rx(&llhp, lle);
+ if (rc < 0)
+ return rc;
+
+ /* llhp.data is only set when we need to send LL_[UNIT]DATA_IND up */
+ if (llhp.data) {
+ msgb_gmmh(msg) = llhp.data;
+ switch (llhp.sapi) {
+ case GPRS_SAPI_GMM:
+ /* send LL_UNITDATA_IND to GMM */
+ rc = gsm0408_gprs_rcvmsg(msg, lle->llme);
+ break;
+ case GPRS_SAPI_SNDCP3:
+ case GPRS_SAPI_SNDCP5:
+ case GPRS_SAPI_SNDCP9:
+ case GPRS_SAPI_SNDCP11:
+ /* send LL_DATA_IND/LL_UNITDATA_IND to SNDCP */
+ rc = sndcp_llunitdata_ind(msg, lle, llhp.data, llhp.data_len);
+ break;
+ case GPRS_SAPI_SMS:
+ /* FIXME */
+ case GPRS_SAPI_TOM2:
+ case GPRS_SAPI_TOM8:
+ /* FIXME: send LL_DATA_IND/LL_UNITDATA_IND to TOM */
+ default:
+ LOGP(DLLC, LOGL_NOTICE, "Unsupported SAPI %u\n", llhp.sapi);
+ rc = -EINVAL;
+ break;
+ }
+ }
+
+ return rc;
+}
+
+/* 04.64 Chapter 7.2.1.1 LLGMM-ASSIGN */
+int gprs_llgmm_assign(struct gprs_llc_llme *llme,
+ uint32_t old_tlli, uint32_t new_tlli,
+ enum gprs_ciph_algo alg, const uint8_t *kc)
+{
+ unsigned int i;
+
+ /* Update the crypto parameters */
+ llme->algo = alg;
+ if (alg != GPRS_ALGO_GEA0)
+ memcpy(llme->kc, kc, sizeof(llme->kc));
+
+ if (old_tlli == 0xffffffff && new_tlli != 0xffffffff) {
+ /* TLLI Assignment 8.3.1 */
+ /* New TLLI shall be assigned and used when (re)transmitting LLC frames */
+ /* If old TLLI != 0xffffffff was assigned to LLME, then TLLI
+ * old is unassigned. Only TLLI new shall be accepted when
+ * received from peer. */
+ if (llme->old_tlli != 0xffffffff) {
+ llme->old_tlli = 0xffffffff;
+ llme->tlli = new_tlli;
+ } else {
+ /* If TLLI old == 0xffffffff was assigned to LLME, then this is
+ * TLLI assignmemt according to 8.3.1 */
+ llme->old_tlli = 0xffffffff;
+ llme->tlli = new_tlli;
+ llme->state = GPRS_LLMS_ASSIGNED;
+ /* 8.5.3.1 For all LLE's */
+ for (i = 0; i < ARRAY_SIZE(llme->lle); i++) {
+ struct gprs_llc_lle *l = &llme->lle[i];
+ l->vu_send = l->vu_recv = 0;
+ l->retrans_ctr = 0;
+ l->state = GPRS_LLES_ASSIGNED_ADM;
+ /* FIXME Set parameters according to table 9 */
+ }
+ }
+ } else if (old_tlli != 0xffffffff && new_tlli != 0xffffffff) {
+ /* TLLI Change 8.3.2 */
+ /* Both TLLI Old and TLLI New are assigned; use New when
+ * (re)transmitting. Accept toth Old and New on Rx */
+ llme->old_tlli = llme->tlli;
+ llme->tlli = new_tlli;
+ llme->state = GPRS_LLMS_ASSIGNED;
+ } else if (old_tlli != 0xffffffff && new_tlli == 0xffffffff) {
+ /* TLLI Unassignment 8.3.3) */
+ llme->tlli = llme->old_tlli = 0;
+ llme->state = GPRS_LLMS_UNASSIGNED;
+ for (i = 0; i < ARRAY_SIZE(llme->lle); i++) {
+ struct gprs_llc_lle *l = &llme->lle[i];
+ l->state = GPRS_LLES_UNASSIGNED;
+ }
+ llme_free(llme);
+ } else
+ return -EINVAL;
+
+ return 0;
+}
+
+int gprs_llc_init(const char *cipher_plugin_path)
+{
+ return gprs_cipher_load(cipher_plugin_path);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-16 06:09:18 +0000