/* NS-over-IP proxy */ /* (C) 2010 by Harald Welte * (C) 2010 by On Waves * 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 struct gbprox_peer { struct llist_head list; /* NS-VC over which we send/receive data to this BVC */ struct gprs_nsvc *nsvc; /* BVCI used for Point-to-Point to this peer */ uint16_t bvci; /* Routeing Area that this peer is part of (raw 04.08 encoding) */ uint8_t ra[6]; }; /* Linked list of all Gb peers (except SGSN) */ static LLIST_HEAD(gbprox_bts_peers); /* Find the gbprox_peer by its BVCI */ static struct gbprox_peer *peer_by_bvci(uint16_t bvci) { struct gbprox_peer *peer; llist_for_each_entry(peer, &gbprox_bts_peers, list) { if (peer->bvci == bvci) return peer; } return NULL; } static struct gbprox_peer *peer_by_nsvc(struct gprs_nsvc *nsvc) { struct gbprox_peer *peer; llist_for_each_entry(peer, &gbprox_bts_peers, list) { if (peer->nsvc == nsvc) return peer; } return NULL; } /* look-up a peer by its Routeing Area Code (RAC) */ static struct gbprox_peer *peer_by_rac(const uint8_t *ra) { struct gbprox_peer *peer; llist_for_each_entry(peer, &gbprox_bts_peers, list) { if (!memcmp(peer->ra, ra, 6)) return peer; } return NULL; } /* look-up a peer by its Location Area Code (LAC) */ static struct gbprox_peer *peer_by_lac(const uint8_t *la) { struct gbprox_peer *peer; llist_for_each_entry(peer, &gbprox_bts_peers, list) { if (!memcmp(peer->ra, la, 5)) return peer; } return NULL; } static struct gbprox_peer *peer_alloc(uint16_t bvci) { struct gbprox_peer *peer; peer = talloc_zero(tall_bsc_ctx, struct gbprox_peer); if (!peer) return NULL; peer->bvci = bvci; llist_add(&peer->list, &gbprox_bts_peers); return peer; } static void peer_free(struct gbprox_peer *peer) { llist_del(&peer->list); talloc_free(peer); } /* FIXME: this needs to go to libosmocore/msgb.c */ static struct msgb *msgb_copy(const struct msgb *msg, const char *name) { struct msgb *new_msg; new_msg = msgb_alloc(msg->data_len, name); if (!new_msg) return NULL; /* copy header */ memcpy(new_msg, msg, sizeof(*new_msg)); /* copy data */ memcpy(new_msg->data, msg->data, new_msg->data_len); return new_msg; } /* strip off the NS header */ static void strip_ns_hdr(struct msgb *msg) { int strip_len = msgb_bssgph(msg) - msg->data; msgb_pull(msg, strip_len); } /* feed a message down the NS-VC associated with the specified peer */ static int gbprox_relay2sgsn(struct msgb *old_msg, uint16_t ns_bvci) { /* create a copy of the message so the old one can * be free()d safely when we return from gbprox_rcvmsg() */ struct msgb *msg = msgb_copy(old_msg, "msgb_relay2sgsn"); DEBUGP(DGPRS, "NSEI=%u proxying BTS->SGSN (NS_BVCI=%u, NSEI=%u)\n", msgb_nsei(msg), ns_bvci, gbcfg.nsip_sgsn_nsei); msgb_bvci(msg) = ns_bvci; msgb_nsei(msg) = gbcfg.nsip_sgsn_nsei; strip_ns_hdr(msg); return gprs_ns_sendmsg(bssgp_nsi, msg); } /* feed a message down the NS-VC associated with the specified peer */ static int gbprox_relay2peer(struct msgb *old_msg, struct gbprox_peer *peer, uint16_t ns_bvci) { /* create a copy of the message so the old one can * be free()d safely when we return from gbprox_rcvmsg() */ struct msgb *msg = msgb_copy(old_msg, "msgb_relay2peer"); DEBUGP(DGPRS, "NSEI=%u proxying SGSN->BSS (NS_BVCI=%u, NSEI=%u)\n", msgb_nsei(msg), ns_bvci, peer->nsvc->nsei); msgb_bvci(msg) = ns_bvci; msgb_nsei(msg) = peer->nsvc->nsei; /* Strip the old NS header, it will be replaced with a new one */ strip_ns_hdr(msg); return gprs_ns_sendmsg(bssgp_nsi, msg); } /* Send a message to a peer identified by ptp_bvci but using ns_bvci * in the NS hdr */ static int gbprox_relay2bvci(struct msgb *msg, uint16_t ptp_bvci, uint16_t ns_bvci) { struct gbprox_peer *peer; peer = peer_by_bvci(ptp_bvci); if (!peer) { LOGP(DGPRS, LOGL_ERROR, "BVCI=%u: Cannot find BSS\n", ptp_bvci); return -ENOENT; } return gbprox_relay2peer(msg, peer, ns_bvci); } /* Receive an incoming signalling message from a BSS-side NS-VC */ static int gbprox_rx_sig_from_bss(struct msgb *msg, struct gprs_nsvc *nsvc, uint16_t ns_bvci) { struct bssgp_normal_hdr *bgph = (struct bssgp_normal_hdr *) msgb_bssgph(msg); struct tlv_parsed tp; uint8_t pdu_type = bgph->pdu_type; int data_len = msgb_bssgp_len(msg) - sizeof(*bgph); struct gbprox_peer *from_peer; struct gprs_ra_id raid; if (ns_bvci != 0) { LOGP(DGPRS, LOGL_NOTICE, "NSEI=%u BVCI=%u is not signalling\n", nsvc->nsei, ns_bvci); return -EINVAL; } /* we actually should never see those two for BVCI == 0, but double-check * just to make sure */ if (pdu_type == BSSGP_PDUT_UL_UNITDATA || pdu_type == BSSGP_PDUT_DL_UNITDATA) { LOGP(DGPRS, LOGL_NOTICE, "NSEI=%u UNITDATA not allowed in " "signalling\n", nsvc->nsei); return -EINVAL; } bssgp_tlv_parse(&tp, bgph->data, data_len); switch (pdu_type) { case BSSGP_PDUT_SUSPEND: case BSSGP_PDUT_RESUME: /* We implement RAC snooping during SUSPEND/RESUME, since * it establishes a relationsip between BVCI/peer and the * routeing area code. The snooped information is then * used for routing the {SUSPEND,RESUME}_[N]ACK back to * the correct BSSGP */ if (!TLVP_PRESENT(&tp, BSSGP_IE_ROUTEING_AREA)) goto err_mand_ie; from_peer = peer_by_nsvc(nsvc); if (!from_peer) goto err_no_peer; memcpy(from_peer->ra, TLVP_VAL(&tp, BSSGP_IE_ROUTEING_AREA), sizeof(from_peer->ra)); gsm48_parse_ra(&raid, from_peer->ra); LOGP(DGPRS, LOGL_INFO, "NSEI=%u BSSGP SUSPEND/RESUME " "RAC snooping: RAC %u-%u-%u-%u behind BVCI=%u, " "NSVCI=%u\n",nsvc->nsei, raid.mcc, raid.mnc, raid.lac, raid.rac , from_peer->bvci, nsvc->nsvci); /* FIXME: This only supports one BSS per RA */ break; case BSSGP_PDUT_BVC_RESET: /* If we receive a BVC reset on the signalling endpoint, we * don't want the SGSN to reset, as the signalling endpoint * is common for all point-to-point BVCs (and thus all BTS) */ if (TLVP_PRESENT(&tp, BSSGP_IE_BVCI)) { uint16_t bvci = ntohs(*(uint16_t *)TLVP_VAL(&tp, BSSGP_IE_BVCI)); LOGP(DGPRS, LOGL_INFO, "NSEI=%u Rx BVC RESET (BVCI=%u)\n", nsvc->nsei, bvci); if (bvci == 0) { /* FIXME: only do this if SGSN is alive! */ LOGP(DGPRS, LOGL_INFO, "NSEI=%u Tx fake " "BVC RESET ACK of BVCI=0\n", nsvc->nsei); return bssgp_tx_simple_bvci(BSSGP_PDUT_BVC_RESET_ACK, nsvc->nsei, 0, ns_bvci); } from_peer = peer_by_bvci(bvci); if (!from_peer) { /* if a PTP-BVC is reset, and we don't know that * PTP-BVCI yet, we should allocate a new peer */ LOGP(DGPRS, LOGL_INFO, "Allocationg new peer for " "BVCI=%u via NSVCI=%u/NSEI=%u\n", bvci, nsvc->nsvci, nsvc->nsei); from_peer = peer_alloc(bvci); from_peer->nsvc = nsvc; } if (TLVP_PRESENT(&tp, BSSGP_IE_CELL_ID)) { struct gprs_ra_id raid; /* We have a Cell Identifier present in this * PDU, this means we can extend our local * state information about this particular cell * */ memcpy(from_peer->ra, TLVP_VAL(&tp, BSSGP_IE_CELL_ID), sizeof(from_peer->ra)); gsm48_parse_ra(&raid, from_peer->ra); LOGP(DGPRS, LOGL_INFO, "NSEI=%u/BVCI=%u " "Cell ID %u-%u-%u-%u\n", nsvc->nsei, bvci, raid.mcc, raid.mnc, raid.lac, raid.rac); } } break; } /* Normally, we can simply pass on all signalling messages from BSS to * SGSN */ return gbprox_relay2sgsn(msg, ns_bvci); err_no_peer: LOGP(DGPRS, LOGL_ERROR, "NSEI=%u(BSS) cannot find peer based on RAC\n", nsvc->nsei); return bssgp_tx_status(BSSGP_CAUSE_UNKNOWN_BVCI, NULL, msg); err_mand_ie: LOGP(DGPRS, LOGL_ERROR, "NSEI=%u(BSS) missing mandatory RA IE\n", nsvc->nsei); return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg); } /* Receive paging request from SGSN, we need to relay to proper BSS */ static int gbprox_rx_paging(struct msgb *msg, struct tlv_parsed *tp, struct gprs_nsvc *nsvc, uint16_t ns_bvci) { struct gbprox_peer *peer = NULL; LOGP(DGPRS, LOGL_INFO, "NSEI=%u(SGSN) BSSGP PAGING ", nsvc->nsei); if (TLVP_PRESENT(tp, BSSGP_IE_BVCI)) { uint16_t bvci = ntohs(*(uint16_t *)TLVP_VAL(tp, BSSGP_IE_BVCI)); LOGPC(DGPRS, LOGL_INFO, "routing by BVCI to peer BVCI=%u\n", bvci); } else if (TLVP_PRESENT(tp, BSSGP_IE_ROUTEING_AREA)) { peer = peer_by_rac(TLVP_VAL(tp, BSSGP_IE_ROUTEING_AREA)); LOGPC(DGPRS, LOGL_INFO, "routing by RAC to peer BVCI=%u\n", peer->bvci); } else if (TLVP_PRESENT(tp, BSSGP_IE_LOCATION_AREA)) { peer = peer_by_lac(TLVP_VAL(tp, BSSGP_IE_LOCATION_AREA)); LOGPC(DGPRS, LOGL_INFO, "routing by LAC to peer BVCI=%u\n", peer->bvci); } else LOGPC(DGPRS, LOGL_INFO, "\n"); if (!peer) { LOGP(DGPRS, LOGL_ERROR, "NSEI=%u(SGSN) BSSGP PAGING: " "unable to route, missing IE\n", nsvc->nsei); return -EINVAL; } return gbprox_relay2peer(msg, peer, ns_bvci); } /* Receive an incoming BVC-RESET message from the SGSN */ static int rx_reset_from_sgsn(struct msgb *msg, struct tlv_parsed *tp, struct gprs_nsvc *nsvc, uint16_t ns_bvci) { struct gbprox_peer *peer; uint16_t ptp_bvci; if (!TLVP_PRESENT(tp, BSSGP_IE_BVCI)) { return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg); } ptp_bvci = ntohs(*(uint16_t *)TLVP_VAL(tp, BSSGP_IE_BVCI)); if (ptp_bvci >= 2) { /* A reset for a PTP BVC was received, forward it to its * respective peer */ peer = peer_by_bvci(ptp_bvci); if (!peer) { LOGP(DGPRS, LOGL_ERROR, "NSEI=%u BVCI=%u: Cannot find BSS\n", nsvc->nsei, ptp_bvci); return bssgp_tx_status(BSSGP_CAUSE_UNKNOWN_BVCI, NULL, msg); } return gbprox_relay2peer(msg, peer, ns_bvci); } /* A reset for the Signalling entity has been received * from the SGSN. As the signalling BVCI is shared * among all the BSS's that we multiplex, it needs to * be relayed */ llist_for_each_entry(peer, &gbprox_bts_peers, list) gbprox_relay2peer(msg, peer, ns_bvci); return 0; } /* Receive an incoming signalling message from the SGSN-side NS-VC */ static int gbprox_rx_sig_from_sgsn(struct msgb *msg, struct gprs_nsvc *nsvc, uint16_t ns_bvci) { struct bssgp_normal_hdr *bgph = (struct bssgp_normal_hdr *) msgb_bssgph(msg); struct tlv_parsed tp; uint8_t pdu_type = bgph->pdu_type; int data_len = msgb_bssgp_len(msg) - sizeof(*bgph); struct gbprox_peer *peer; uint16_t bvci; int rc = 0; if (ns_bvci != 0) { LOGP(DGPRS, LOGL_NOTICE, "NSEI=%u(SGSN) BVCI=%u is not " "signalling\n", nsvc->nsei, ns_bvci); /* FIXME: Send proper error message */ return -EINVAL; } /* we actually should never see those two for BVCI == 0, but double-check * just to make sure */ if (pdu_type == BSSGP_PDUT_UL_UNITDATA || pdu_type == BSSGP_PDUT_DL_UNITDATA) { LOGP(DGPRS, LOGL_NOTICE, "NSEI=%u(SGSN) UNITDATA not allowed in " "signalling\n", nsvc->nsei); return bssgp_tx_status(BSSGP_CAUSE_PROTO_ERR_UNSPEC, NULL, msg); } rc = bssgp_tlv_parse(&tp, bgph->data, data_len); switch (pdu_type) { case BSSGP_PDUT_BVC_RESET: rc = rx_reset_from_sgsn(msg, &tp, nsvc, ns_bvci); break; case BSSGP_PDUT_FLUSH_LL: case BSSGP_PDUT_BVC_BLOCK_ACK: case BSSGP_PDUT_BVC_UNBLOCK_ACK: case BSSGP_PDUT_BVC_RESET_ACK: /* simple case: BVCI IE is mandatory */ if (!TLVP_PRESENT(&tp, BSSGP_IE_BVCI)) goto err_mand_ie; bvci = ntohs(*(uint16_t *)TLVP_VAL(&tp, BSSGP_IE_BVCI)); rc = gbprox_relay2bvci(msg, bvci, ns_bvci); break; case BSSGP_PDUT_PAGING_PS: case BSSGP_PDUT_PAGING_CS: /* process the paging request (LAC/RAC lookup) */ rc = gbprox_rx_paging(msg, &tp, nsvc, ns_bvci); break; case BSSGP_PDUT_STATUS: /* Some exception has occurred */ LOGP(DGPRS, LOGL_NOTICE, "NSEI=%u(SGSN) BSSGP STATUS ", nsvc->nsei); if (!TLVP_PRESENT(&tp, BSSGP_IE_CAUSE)) { LOGPC(DGPRS, LOGL_NOTICE, "\n"); goto err_mand_ie; } LOGPC(DGPRS, LOGL_NOTICE, "cause=0x%02x(%s) ", *TLVP_VAL(&tp, BSSGP_IE_CAUSE), bssgp_cause_str(*TLVP_VAL(&tp, BSSGP_IE_CAUSE))); if (TLVP_PRESENT(&tp, BSSGP_IE_BVCI)) { uint16_t *bvci = (uint16_t *) TLVP_VAL(&tp, BSSGP_IE_BVCI); LOGPC(DGPRS, LOGL_NOTICE, "BVCI=%u\n", ntohs(*bvci)); } else LOGPC(DGPRS, LOGL_NOTICE, "\n"); break; /* those only exist in the SGSN -> BSS direction */ case BSSGP_PDUT_SUSPEND_ACK: case BSSGP_PDUT_SUSPEND_NACK: case BSSGP_PDUT_RESUME_ACK: case BSSGP_PDUT_RESUME_NACK: /* RAC IE is mandatory */ if (!TLVP_PRESENT(&tp, BSSGP_IE_ROUTEING_AREA)) goto err_mand_ie; peer = peer_by_rac(TLVP_VAL(&tp, BSSGP_IE_ROUTEING_AREA)); if (!peer) goto err_no_peer; rc = gbprox_relay2peer(msg, peer, ns_bvci); break; case BSSGP_PDUT_SGSN_INVOKE_TRACE: LOGP(DGPRS, LOGL_ERROR, "NSEI=%u(SGSN) BSSGP INVOKE TRACE not supported\n",nsvc->nsei); rc = bssgp_tx_status(BSSGP_CAUSE_PDU_INCOMP_FEAT, NULL, msg); break; default: LOGP(DGPRS, LOGL_NOTICE, "BSSGP PDU type 0x%02x unknown\n", pdu_type); rc = bssgp_tx_status(BSSGP_CAUSE_PROTO_ERR_UNSPEC, NULL, msg); break; } return rc; err_mand_ie: LOGP(DGPRS, LOGL_ERROR, "NSEI=%u(SGSN) missing mandatory IE\n", nsvc->nsei); return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg); err_no_peer: LOGP(DGPRS, LOGL_ERROR, "NSEI=%u(SGSN) cannot find peer based on RAC\n", nsvc->nsei); return bssgp_tx_status(BSSGP_CAUSE_UNKNOWN_BVCI, NULL, msg); } /* Main input function for Gb proxy */ int gbprox_rcvmsg(struct msgb *msg, struct gprs_nsvc *nsvc, uint16_t ns_bvci) { int rc; /* Only BVCI=0 messages need special treatment */ if (ns_bvci == 0 || ns_bvci == 1) { if (nsvc->remote_end_is_sgsn) rc = gbprox_rx_sig_from_sgsn(msg, nsvc, ns_bvci); else rc = gbprox_rx_sig_from_bss(msg, nsvc, ns_bvci); } else { /* All other BVCI are PTP and thus can be simply forwarded */ if (!nsvc->remote_end_is_sgsn) { rc = gbprox_relay2sgsn(msg, ns_bvci); } else { struct gbprox_peer *peer = peer_by_bvci(ns_bvci); if (!peer) { LOGP(DGPRS, LOGL_INFO, "Allocationg new peer for " "BVCI=%u via NSVC=%u/NSEI=%u\n", ns_bvci, nsvc->nsvci, nsvc->nsei); peer = peer_alloc(ns_bvci); peer->nsvc = nsvc; } rc = gbprox_relay2peer(msg, peer, ns_bvci); } } return rc; } int gbprox_reset_persistent_nsvcs(struct gprs_ns_inst *nsi) { struct gprs_nsvc *nsvc; llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) { if (!nsvc->persistent) continue; gprs_nsvc_reset(nsvc, NS_CAUSE_OM_INTERVENTION); } return 0; } /* Signal handler for signals from NS layer */ int gbprox_signal(unsigned int subsys, unsigned int signal, void *handler_data, void *signal_data) { struct ns_signal_data *nssd = signal_data; struct gprs_nsvc *nsvc = nssd->nsvc; struct gbprox_peer *peer; if (subsys != SS_NS) return 0; if (signal == S_NS_RESET && nsvc->nsei == gbcfg.nsip_sgsn_nsei) { /* We have received a NS-RESET from the NSEI and NSVC * of the SGSN. This might happen with SGSN that start * their own NS-RESET procedure without waiting for our * NS-RESET */ nsvc->remote_end_is_sgsn = 1; } if (signal == S_NS_ALIVE_EXP && nsvc->remote_end_is_sgsn) { LOGP(DGPRS, LOGL_NOTICE, "Tns alive expired too often, " "re-starting RESET procedure\n"); nsip_connect(nsvc->nsi, &nsvc->ip.bts_addr, nsvc->nsei, nsvc->nsvci); } /* We currently only care about signals from the SGSN */ if (!nsvc->remote_end_is_sgsn) return 0; /* iterate over all BTS peers and send the respective PDU */ llist_for_each_entry(peer, &gbprox_bts_peers, list) { switch (signal) { case S_NS_RESET: gprs_ns_tx_reset(peer->nsvc, nssd->cause); break; case S_NS_BLOCK: gprs_ns_tx_block(peer->nsvc, nssd->cause); break; case S_NS_UNBLOCK: gprs_ns_tx_unblock(peer->nsvc); break; } } return 0; } #include gDEFUN(show_gbproxy, show_gbproxy_cmd, "show gbproxy", SHOW_STR "Display information about the Gb proxy") { struct gbprox_peer *peer; llist_for_each_entry(peer, &gbprox_bts_peers, list) { struct gprs_nsvc *nsvc = peer->nsvc; struct gprs_ra_id raid; gsm48_parse_ra(&raid, peer->ra); vty_out(vty, "NSEI %5u, NS-VC %5u, PTP-BVCI %u, " "RAC %u-%u-%u-%u%s", nsvc->nsei, nsvc->nsvci, peer->bvci, raid.mcc, raid.mnc, raid.lac, raid.rac, VTY_NEWLINE); if (nsvc->nsi->ll == GPRS_NS_LL_UDP) vty_out(vty, " remote address %s:%u%s", inet_ntoa(nsvc->ip.bts_addr.sin_addr), ntohs(nsvc->ip.bts_addr.sin_port), VTY_NEWLINE); } return CMD_SUCCESS; }