/* GSM Mobile Radio Interface Layer 3 messages on the A-bis interface * 3GPP TS 04.08 version 7.21.0 Release 1998 / ETSI TS 100 940 V7.21.0 */ /* (C) 2009 by Harald Welte * * 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. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* 10.5.5.14 GPRS MM Cause / Table 10.5.147 */ struct value_string gmm_cause_names[] = { /* FIXME */ { GMM_CAUSE_SEM_INCORR_MSG, "Semantically incorrect message" }, { GMM_CAUSE_INV_MAND_INFO, "Invalid mandatory information" }, { GMM_CAUSE_MSGT_NOTEXIST_NOTIMPL, "Message type non-existant or not implemented" }, { GMM_CAUSE_MSGT_INCOMP_P_STATE, "Message type not compatible with protocol state" }, { GMM_CAUSE_IE_NOTEXIST_NOTIMPL, "Information element non-existent or not implemented" }, { GMM_CAUSE_COND_IE_ERR, "Conditional IE error" }, { GMM_CAUSE_MSG_INCOMP_P_STATE, "Message not compatible with protocol state " }, { GMM_CAUSE_PROTO_ERR_UNSPEC, "Protocol error, unspecified" }, { 0, NULL } }; /* 10.5.6.6 SM Cause / Table 10.5.157 */ struct value_string gsm_cause_names[] = { { GSM_CAUSE_INSUFF_RSRC, "Insufficient resources" }, { GSM_CAUSE_MISSING_APN, "Missing or unknown APN" }, { GSM_CAUSE_UNKNOWN_PDP, "Unknown PDP address or PDP type" }, { GSM_CAUSE_AUTH_FAILED, "User Authentication failed" }, { GSM_CAUSE_ACT_REJ_GGSN, "Activation rejected by GGSN" }, { GSM_CAUSE_ACT_REJ_UNSPEC, "Activation rejected, unspecified" }, { GSM_CAUSE_SERV_OPT_NOTSUPP, "Service option not supported" }, { GSM_CAUSE_REQ_SERV_OPT_NOTSUB, "Requested service option not subscribed" }, { GSM_CAUSE_SERV_OPT_TEMP_OOO, "Service option temporarily out of order" }, { GSM_CAUSE_NSAPI_IN_USE, "NSAPI already used" }, { GSM_CAUSE_DEACT_REGULAR, "Regular deactivation" }, { GSM_CAUSE_QOS_NOT_ACCEPTED, "QoS not accepted" }, { GSM_CAUSE_NET_FAIL, "Network Failure" }, { GSM_CAUSE_REACT_RQD, "Reactivation required" }, { GSM_CAUSE_FEATURE_NOTSUPP, "Feature not supported " }, { GSM_CAUSE_INVALID_TRANS_ID, "Invalid transaction identifier" }, { GSM_CAUSE_SEM_INCORR_MSG, "Semantically incorrect message" }, { GSM_CAUSE_INV_MAND_INFO, "Invalid mandatory information" }, { GSM_CAUSE_MSGT_NOTEXIST_NOTIMPL, "Message type non-existant or not implemented" }, { GSM_CAUSE_MSGT_INCOMP_P_STATE, "Message type not compatible with protocol state" }, { GSM_CAUSE_IE_NOTEXIST_NOTIMPL, "Information element non-existent or not implemented" }, { GSM_CAUSE_COND_IE_ERR, "Conditional IE error" }, { GSM_CAUSE_MSG_INCOMP_P_STATE, "Message not compatible with protocol state " }, { GSM_CAUSE_PROTO_ERR_UNSPEC, "Protocol error, unspecified" }, { 0, NULL } }; static const char *att_name(u_int8_t type) { switch (type) { case GPRS_ATT_T_ATTACH: return "GPRS attach"; case GPRS_ATT_T_ATT_WHILE_IMSI: return "GPRS attach while IMSI attached"; case GPRS_ATT_T_COMBINED: return "Combined GPRS/IMSI attach"; default: return "unknown"; } } static const char *upd_name(u_int8_t type) { switch (type) { case GPRS_UPD_T_RA: return "RA updating"; case GPRS_UPD_T_RA_LA: return "combined RA/LA updating"; case GPRS_UPD_T_RA_LA_IMSI_ATT: return "combined RA/LA updating + IMSI attach"; case GPRS_UPD_T_PERIODIC: return "periodic updating"; } return "unknown"; } /* Send a message through the underlying layer */ static int gsm48_gmm_sendmsg(struct msgb *msg, int command) { return gprs_llc_tx_ui(msg, GPRS_SAPI_GMM, command); } /* Chapter 9.4.2: Attach accept */ static int gsm48_tx_gmm_att_ack(struct msgb *old_msg) { struct msgb *msg = gsm48_msgb_alloc(); struct gsm48_hdr *gh; struct gsm48_attach_ack *aa; DEBUGP(DMM, "<- GPRS ATTACH ACCEPT\n"); msgb_tlli(msg) = msgb_tlli(old_msg); msg->trx = old_msg->trx; gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh)); gh->proto_discr = GSM48_PDISC_MM_GPRS; gh->msg_type = GSM48_MT_GMM_ATTACH_ACK; aa = (struct gsm48_attach_ack *) msgb_put(msg, sizeof(*aa)); aa->force_stby = 0; /* not indicated */ aa->att_result = 1; /* GPRS only */ aa->ra_upd_timer = GPRS_TMR_MINUTE | 10; aa->radio_prio = 4; /* lowest */ //FIXME gsm48_ra_id_by_bts(aa->ra_id.digits, old_msg->trx->bts); /* Option: P-TMSI signature, allocated P-TMSI, MS ID, ... */ return gsm48_gmm_sendmsg(msg, 0); } /* Chapter 9.4.5: Attach reject */ static int gsm48_tx_gmm_att_rej(struct msgb *old_msg, u_int8_t gmm_cause) { struct msgb *msg = gsm48_msgb_alloc(); struct gsm48_hdr *gh; DEBUGP(DMM, "<- GPRS ATTACH REJECT\n"); msgb_tlli(msg) = msgb_tlli(old_msg); msg->trx = old_msg->trx; gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh) + 1); gh->proto_discr = GSM48_PDISC_MM_GPRS; gh->msg_type = GSM48_MT_GMM_ATTACH_REJ; gh->data[0] = gmm_cause; return gsm48_gmm_sendmsg(msg, 0); } /* Transmit Chapter 9.4.12 Identity Request */ static int gsm48_tx_gmm_id_req(struct msgb *old_msg, u_int8_t id_type) { struct msgb *msg = gsm48_msgb_alloc(); struct gsm48_hdr *gh; DEBUGP(DMM, "-> GPRS IDENTITY REQUEST: mi_type=%02x\n", id_type); msgb_tlli(msg) = msgb_tlli(old_msg); msg->trx = old_msg->trx; gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh) + 1); gh->proto_discr = GSM48_PDISC_MM_GPRS; gh->msg_type = GSM48_MT_GMM_ID_REQ; /* 10.5.5.9 ID type 2 + identity type and 10.5.5.7 'force to standby' IE */ gh->data[0] = id_type & 0xf; return gsm48_gmm_sendmsg(msg, 0); } /* Check if we can already authorize a subscriber */ static int gsm48_gmm_authorize(struct sgsn_mm_ctx *ctx, struct msgb *msg) { if (strlen(ctx->imei) && strlen(ctx->imsi)) { ctx->mm_state = GMM_REGISTERED_NORMAL; return gsm48_tx_gmm_att_ack(msg); } if (!strlen(ctx->imei)) return gsm48_tx_gmm_id_req(msg, GSM_MI_TYPE_IMEI); if (!strlen(ctx->imsi)) return gsm48_tx_gmm_id_req(msg, GSM_MI_TYPE_IMSI); return 0; } /* Parse Chapter 9.4.13 Identity Response */ static int gsm48_rx_gmm_id_resp(struct msgb *msg) { struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg); u_int8_t mi_type = gh->data[1] & GSM_MI_TYPE_MASK; char mi_string[GSM48_MI_SIZE]; struct gprs_ra_id ra_id; struct sgsn_mm_ctx *ctx; gsm48_mi_to_string(mi_string, sizeof(mi_string), &gh->data[1], gh->data[0]); DEBUGP(DMM, "GMM IDENTITY RESPONSE: mi_type=0x%02x MI(%s) ", mi_type, mi_string); //FIXME gprs_ra_id_by_bts(&ra_id, msg->trx->bts); ctx = sgsn_mm_ctx_by_tlli(msgb_tlli(msg), &ra_id); if (!ctx) { DEBUGP(DMM, "from unknown TLLI 0x%08x?!?\n", msgb_tlli(msg)); return -EINVAL; } switch (mi_type) { case GSM_MI_TYPE_IMSI: /* we already have a mm context with current TLLI, but no * P-TMSI / IMSI yet. What we now need to do is to fill * this initial context with data from the HLR */ strncpy(ctx->imsi, mi_string, sizeof(ctx->imei)); break; case GSM_MI_TYPE_IMEI: strncpy(ctx->imei, mi_string, sizeof(ctx->imei)); break; case GSM_MI_TYPE_IMEISV: break; } DEBUGPC(DMM, "\n"); /* Check if we can let the mobile station enter */ return gsm48_gmm_authorize(ctx, msg); } static void attach_rej_cb(void *data) { struct sgsn_mm_ctx *ctx = data; /* FIXME: determine through which BTS/TRX to send this */ //gsm48_tx_gmm_att_rej(ctx->tlli, GMM_CAUSE_MS_ID_NOT_DERIVED); ctx->mm_state = GMM_DEREGISTERED; /* FIXME: release the context */ } static void schedule_reject(struct sgsn_mm_ctx *ctx) { ctx->T = 3370; ctx->timer.cb = attach_rej_cb; ctx->timer.data = ctx; bsc_schedule_timer(&ctx->timer, 6, 0); } /* Section 9.4.1 Attach request */ static int gsm48_rx_gmm_att_req(struct msgb *msg) { struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg); u_int8_t *cur = gh->data, *msnc, *mi, *old_ra_info; u_int8_t msnc_len, att_type, mi_len, mi_type; u_int16_t drx_par; u_int32_t tmsi; char mi_string[GSM48_MI_SIZE]; struct gprs_ra_id ra_id; struct sgsn_mm_ctx *ctx; DEBUGP(DMM, "GMM ATTACH REQUEST "); /* As per TS 04.08 Chapter 4.7.1.4, the attach request arrives either * with a foreign TLLI (P-TMSI that was allocated to the MS before), * or with random TLLI. */ //FIXME gprs_ra_id_by_bts(&ra_id, msg->trx->bts); /* MS network capability 10.5.5.12 */ msnc_len = *cur++; msnc = cur; if (msnc_len > 2) goto err_inval; cur += msnc_len; /* aTTACH Type 10.5.5.2 */ att_type = *cur++ & 0x0f; /* DRX parameter 10.5.5.6 */ drx_par = *cur++; drx_par |= *cur++ << 8; /* Mobile Identity (P-TMSI or IMSI) 10.5.1.4 */ mi_len = *cur++; mi = cur; if (mi_len > 8) goto err_inval; mi_type = *mi & GSM_MI_TYPE_MASK; cur += mi_len; gsm48_mi_to_string(mi_string, sizeof(mi_string), mi, mi_len); DEBUGPC(DMM, "MI(%s) type=\"%s\" ", mi_string, att_name(att_type)); /* Old routing area identification 10.5.5.15 */ old_ra_info = cur; cur += 6; /* MS Radio Access Capability 10.5.5.12a */ /* Optional: Old P-TMSI Signature, Requested READY timer, TMSI Status */ switch (mi_type) { case GSM_MI_TYPE_IMSI: /* Try to find MM context based on IMSI */ ctx = sgsn_mm_ctx_by_imsi(mi_string); if (!ctx) { #if 0 return gsm48_tx_gmm_att_rej(msg, GMM_CAUSE_IMSI_UNKNOWN); #else /* As a temorary hack, we simply assume that the IMSI exists */ ctx = sgsn_mm_ctx_alloc(0, &ra_id); if (!ctx) return gsm48_tx_gmm_att_rej(msg, GMM_CAUSE_NET_FAIL); strncpy(ctx->imsi, mi_string, sizeof(ctx->imsi)); #endif } /* FIXME: Start some timer */ ctx->mm_state = GMM_COMMON_PROC_INIT; ctx->tlli = msgb_tlli(msg); break; case GSM_MI_TYPE_TMSI: tmsi = strtoul(mi_string, NULL, 10); /* Try to find MM context based on P-TMSI */ ctx = sgsn_mm_ctx_by_ptmsi(tmsi); if (!ctx) { ctx = sgsn_mm_ctx_alloc(msgb_tlli(msg), &ra_id); /* FIXME: Start some timer */ ctx->mm_state = GMM_COMMON_PROC_INIT; ctx->tlli = msgb_tlli(msg); } break; default: break; } /* FIXME: allocate a new P-TMSI (+ P-TMSI signature) */ /* FIXME: update the TLLI with the new local TLLI based on the P-TMSI */ DEBUGPC(DMM, "\n"); return ctx ? gsm48_gmm_authorize(ctx, msg) : 0; err_inval: DEBUGPC(DMM, "\n"); return gsm48_tx_gmm_att_rej(msg, GMM_CAUSE_SEM_INCORR_MSG); } /* Chapter 9.4.15: Routing area update accept */ static int gsm48_tx_gmm_ra_upd_ack(struct msgb *old_msg) { struct msgb *msg = gsm48_msgb_alloc(); struct gsm48_hdr *gh; struct gsm48_ra_upd_ack *rua; DEBUGP(DMM, "<- ROUTING AREA UPDATE ACCEPT\n"); msgb_tlli(msg) = msgb_tlli(old_msg); msg->trx = old_msg->trx; gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh)); gh->proto_discr = GSM48_PDISC_MM_GPRS; gh->msg_type = GSM48_MT_GMM_RA_UPD_ACK; rua = (struct gsm48_ra_upd_ack *) msgb_put(msg, sizeof(*rua)); rua->force_stby = 0; /* not indicated */ rua->upd_result = 0; /* RA updated */ rua->ra_upd_timer = GPRS_TMR_MINUTE | 10; //FIXME gsm48_ra_id_by_bts(rua->ra_id.digits, old_msg->trx->bts); /* Option: P-TMSI signature, allocated P-TMSI, MS ID, ... */ return gsm48_gmm_sendmsg(msg, 0); } /* Chapter 9.4.17: Routing area update reject */ static int gsm48_tx_gmm_ra_upd_rej(struct msgb *old_msg, u_int8_t cause) { struct msgb *msg = gsm48_msgb_alloc(); struct gsm48_hdr *gh; DEBUGP(DMM, "<- ROUTING AREA UPDATE REJECT\n"); msgb_tlli(msg) = msgb_tlli(old_msg); msg->trx = old_msg->trx; gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh) + 2); gh->proto_discr = GSM48_PDISC_MM_GPRS; gh->msg_type = GSM48_MT_GMM_RA_UPD_REJ; gh->data[0] = cause; gh->data[1] = 0; /* ? */ /* Option: P-TMSI signature, allocated P-TMSI, MS ID, ... */ return gsm48_gmm_sendmsg(msg, 0); } /* Chapter 9.4.14: Routing area update request */ static int gsm48_rx_gmm_ra_upd_req(struct msgb *msg) { struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg); struct sgsn_mm_ctx *mmctx; u_int8_t *cur = gh->data; struct gprs_ra_id old_ra_id; u_int8_t upd_type; /* Update Type 10.5.5.18 */ upd_type = *cur++ & 0x0f; DEBUGP(DMM, "GMM RA UPDATE REQUEST type=\"%s\" ", upd_name(upd_type)); /* Old routing area identification 10.5.5.15 */ gsm48_parse_ra(&old_ra_id, cur); cur += 6; /* MS Radio Access Capability 10.5.5.12a */ /* Optional: Old P-TMSI Signature, Requested READY timer, TMSI Status, * DRX parameter, MS network capability */ switch (upd_type) { case GPRS_UPD_T_RA_LA: case GPRS_UPD_T_RA_LA_IMSI_ATT: DEBUGPC(DMM, " unsupported in Mode III, is your SI13 corrupt?\n"); return gsm48_tx_gmm_ra_upd_rej(msg, GMM_CAUSE_PROTO_ERR_UNSPEC); break; case GPRS_UPD_T_RA: case GPRS_UPD_T_PERIODIC: break; } /* Look-up the MM context based on old RA-ID and TLLI */ mmctx = sgsn_mm_ctx_by_tlli(msgb_tlli(msg), &old_ra_id); if (!mmctx || mmctx->mm_state == GMM_DEREGISTERED) { /* The MS has to perform GPRS attach */ DEBUGPC(DMM, " REJECT\n"); return gsm48_tx_gmm_ra_upd_rej(msg, GMM_CAUSE_IMPL_DETACHED); } /* FIXME: Update the MM context with the new RA-ID */ /* FIXME: Update the MM context with the new TLLI */ /* FIXME: Update the MM context with the MS radio acc capabilities */ /* FIXME: Update the MM context with the MS network capabilities */ DEBUGPC(DMM, " ACCEPT\n"); return gsm48_tx_gmm_ra_upd_ack(msg); } static int gsm48_rx_gmm_status(struct msgb *msg) { struct gsm48_hdr *gh = msgb_l3(msg); DEBUGP(DMM, "GPRS MM STATUS (cause: %s)\n", get_value_string(gmm_cause_names, gh->data[0])); return 0; } /* GPRS Mobility Management */ static int gsm0408_rcv_gmm(struct msgb *msg) { struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg); int rc; switch (gh->msg_type) { case GSM48_MT_GMM_RA_UPD_REQ: rc = gsm48_rx_gmm_ra_upd_req(msg); break; case GSM48_MT_GMM_ATTACH_REQ: rc = gsm48_rx_gmm_att_req(msg); break; case GSM48_MT_GMM_ID_RESP: rc = gsm48_rx_gmm_id_resp(msg); break; case GSM48_MT_GMM_STATUS: rc = gsm48_rx_gmm_status(msg); break; case GSM48_MT_GMM_RA_UPD_COMPL: /* only in case SGSN offered new P-TMSI */ case GSM48_MT_GMM_ATTACH_COMPL: /* only in case SGSN offered new P-TMSI */ case GSM48_MT_GMM_DETACH_REQ: case GSM48_MT_GMM_PTMSI_REALL_COMPL: case GSM48_MT_GMM_AUTH_CIPH_RESP: DEBUGP(DMM, "Unimplemented GSM 04.08 GMM msg type 0x%02x\n", gh->msg_type); break; default: DEBUGP(DMM, "Unknown GSM 04.08 GMM msg type 0x%02x\n", gh->msg_type); break; } return rc; } /* Section 9.5.2: Ativate PDP Context Accept */ static int gsm48_tx_gsm_act_pdp_acc(struct msgb *old_msg, struct gsm48_act_pdp_ctx_req *req) { struct gsm48_hdr *old_gh = (struct gsm48_hdr *) msgb_gmmh(old_msg); struct msgb *msg = gsm48_msgb_alloc(); struct gsm48_act_pdp_ctx_ack *act_ack; struct gsm48_hdr *gh; u_int8_t transaction_id = ((old_gh->proto_discr >> 4) ^ 0x8); /* flip */ DEBUGP(DMM, "<- ACTIVATE PDP CONTEXT ACK\n"); msgb_tlli(msg) = msgb_tlli(old_msg); msg->trx = old_msg->trx; gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh)); gh->proto_discr = GSM48_PDISC_SM_GPRS | (transaction_id << 4); gh->msg_type = GSM48_MT_GSM_ACT_PDP_ACK; act_ack = (struct gsm48_act_pdp_ctx_ack *) msgb_put(msg, sizeof(*act_ack)); act_ack->llc_sapi = req->req_llc_sapi; memcpy(act_ack->qos_lv, req->req_qos_lv, sizeof(act_ack->qos_lv)); //act_ack->radio_prio = 4; return gsm48_gmm_sendmsg(msg, 0); } /* Section 9.5.9: Deactivate PDP Context Accept */ static int gsm48_tx_gsm_deact_pdp_acc(struct msgb *old_msg) { struct gsm48_hdr *old_gh = (struct gsm48_hdr *) msgb_gmmh(old_msg); struct msgb *msg = gsm48_msgb_alloc(); struct gsm48_hdr *gh; u_int8_t transaction_id = ((old_gh->proto_discr >> 4) ^ 0x8); /* flip */ DEBUGP(DMM, "<- DEACTIVATE PDP CONTEXT ACK\n"); msgb_tlli(msg) = msgb_tlli(old_msg); msg->trx = old_msg->trx; gh = (struct gsm48_hdr *) msgb_put(msg, sizeof(*gh)); gh->proto_discr = GSM48_PDISC_SM_GPRS | (transaction_id << 4); gh->msg_type = GSM48_MT_GSM_DEACT_PDP_ACK; return gsm48_gmm_sendmsg(msg, 0); } /* Section 9.5.1: Activate PDP Context Request */ static int gsm48_rx_gsm_act_pdp_req(struct msgb *msg) { struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg); struct gsm48_act_pdp_ctx_req *act_req = (struct gsm48_act_pdp_ctx_req *) gh->data; u_int8_t *pdp_addr_lv = act_req->data; DEBUGP(DMM, "ACTIVATE PDP CONTEXT REQ\n"); /* FIXME: parse access point name + IPCP config options */ return gsm48_tx_gsm_act_pdp_acc(msg, act_req); } /* Section 9.5.8: Deactivate PDP Context Request */ static int gsm48_rx_gsm_deact_pdp_req(struct msgb *msg) { struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg); DEBUGP(DMM, "DEACTIVATE PDP CONTEXT REQ (cause: %s)\n", get_value_string(gsm_cause_names, gh->data[0])); return gsm48_tx_gsm_deact_pdp_acc(msg); } static int gsm48_rx_gsm_status(struct msgb *msg) { struct gsm48_hdr *gh = msgb_l3(msg); DEBUGP(DMM, "GPRS SM STATUS (cause: %s)\n", get_value_string(gsm_cause_names, gh->data[0])); return 0; } /* GPRS Session Management */ static int gsm0408_rcv_gsm(struct msgb *msg) { struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg); int rc; switch (gh->msg_type) { case GSM48_MT_GSM_ACT_PDP_REQ: rc = gsm48_rx_gsm_act_pdp_req(msg); break; case GSM48_MT_GSM_DEACT_PDP_REQ: rc = gsm48_rx_gsm_deact_pdp_req(msg); case GSM48_MT_GSM_STATUS: rc = gsm48_rx_gsm_status(msg); break; case GSM48_MT_GSM_REQ_PDP_ACT_REJ: case GSM48_MT_GSM_ACT_AA_PDP_REQ: case GSM48_MT_GSM_DEACT_AA_PDP_REQ: DEBUGP(DMM, "Unimplemented GSM 04.08 GSM msg type 0x%02x\n", gh->msg_type); break; default: DEBUGP(DMM, "Unknown GSM 04.08 GSM msg type 0x%02x\n", gh->msg_type); break; } return rc; } /* Main entry point for incoming 04.08 GPRS messages */ int gsm0408_gprs_rcvmsg(struct msgb *msg) { struct gsm48_hdr *gh = (struct gsm48_hdr *) msgb_gmmh(msg); u_int8_t pdisc = gh->proto_discr & 0x0f; int rc = -EINVAL; switch (pdisc) { case GSM48_PDISC_MM_GPRS: rc = gsm0408_rcv_gmm(msg); break; case GSM48_PDISC_SM_GPRS: rc = gsm0408_rcv_gsm(msg); break; default: DEBUGP(DMM, "Unknown GSM 04.08 discriminator 0x%02x\n", pdisc); break; } return rc; } /* Determine the 'struct gsm_bts' from a RA ID */ struct gsm_bts *gsm48_bts_by_ra_id(struct gsm_network *net, const u_int8_t *buf, unsigned int len) { struct gprs_ra_id raid; struct gsm_bts *bts; if (len < 6) return NULL; gsm48_parse_ra(&raid, buf); if (net->country_code != raid.mcc || net->network_code != raid.mnc) return NULL; llist_for_each_entry(bts, &net->bts_list, list) { /* FIXME: we actually also need to check the * routing area code! */ if (bts->location_area_code == raid.lac) return bts; } return NULL; }