| /* NS-over-IP proxy */ |
| |
| /* (C) 2010 by Harald Welte <laforge@gnumonks.org> |
| * (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 <unistd.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <getopt.h> |
| #include <errno.h> |
| #include <sys/fcntl.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| |
| #include <osmocore/talloc.h> |
| #include <osmocore/select.h> |
| |
| #include <openbsc/signal.h> |
| #include <openbsc/debug.h> |
| #include <openbsc/gprs_ns.h> |
| #include <openbsc/gprs_bssgp.h> |
| #include <openbsc/gb_proxy.h> |
| |
| 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); |
| |
| extern struct gprs_ns_inst *gbprox_nsi; |
| |
| /* 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); |
| } |
| |
| /* 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); |
| } |
| |
| /* FIXME: this is copy+paste from gprs_bssgp.c */ |
| static inline struct msgb *bssgp_msgb_alloc(void) |
| { |
| return msgb_alloc_headroom(4096, 128, "BSSGP"); |
| } |
| static int bssgp_tx_simple_bvci(uint8_t pdu_type, uint16_t nsei, |
| uint16_t bvci, uint16_t ns_bvci) |
| { |
| struct msgb *msg = bssgp_msgb_alloc(); |
| struct bssgp_normal_hdr *bgph = |
| (struct bssgp_normal_hdr *) msgb_put(msg, sizeof(*bgph)); |
| uint16_t _bvci; |
| |
| msgb_nsei(msg) = nsei; |
| msgb_bvci(msg) = ns_bvci; |
| |
| bgph->pdu_type = pdu_type; |
| _bvci = htons(bvci); |
| msgb_tvlv_put(msg, BSSGP_IE_BVCI, 2, (uint8_t *) &_bvci); |
| |
| return gprs_ns_sendmsg(gbprox_nsi, msg); |
| } |
| |
| |
| /* feed a message down the NS-VC associated with the specified peer */ |
| static int gbprox_relay2sgsn(struct msgb *msg, uint16_t ns_bvci) |
| { |
| DEBUGP(DGPRS, "NSEI=%u proxying to 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(gbprox_nsi, msg); |
| } |
| |
| /* feed a message down the NS-VC associated with the specified peer */ |
| static int gbprox_relay2peer(struct msgb *msg, struct gbprox_peer *peer, |
| uint16_t ns_bvci) |
| { |
| DEBUGP(DGPRS, "NSEI=%u proxying to to 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_ns_hdr(msg); |
| |
| return gprs_ns_sendmsg(gbprox_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) |
| 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); |
| DEBUGP(DGPRS, "NSEI=%u 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)); |
| if (bvci == 0) { |
| /* FIXME: only do this if SGSN is alive! */ |
| LOGP(DGPRS, LOGL_INFO, "NSEI=%u Sending 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); |
| } |
| } |
| break; |
| } |
| |
| /* Normally, we can simply pass on all signalling messages from BSS to SGSN */ |
| return gbprox_relay2sgsn(msg, ns_bvci); |
| err_no_peer: |
| err_mand_ie: |
| /* FIXME: do something */ |
| ; |
| } |
| |
| /* 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; |
| |
| if (TLVP_PRESENT(tp, BSSGP_IE_BVCI)) { |
| uint16_t bvci = ntohs(*(uint16_t *)TLVP_VAL(tp, BSSGP_IE_BVCI)); |
| return gbprox_relay2bvci(msg, bvci, ns_bvci); |
| } else if (TLVP_PRESENT(tp, BSSGP_IE_ROUTEING_AREA)) { |
| peer = peer_by_rac(TLVP_VAL(tp, BSSGP_IE_ROUTEING_AREA)); |
| return gbprox_relay2peer(msg, peer, ns_bvci); |
| } else if (TLVP_PRESENT(tp, BSSGP_IE_LOCATION_AREA)) { |
| peer = peer_by_lac(TLVP_VAL(tp, BSSGP_IE_LOCATION_AREA)); |
| return gbprox_relay2peer(msg, peer, ns_bvci); |
| } else |
| return -EINVAL; |
| } |
| |
| /* 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); |
| 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 -EINVAL; |
| } |
| |
| rc = bssgp_tlv_parse(&tp, bgph->data, data_len); |
| |
| switch (pdu_type) { |
| case BSSGP_PDUT_FLUSH_LL: |
| case BSSGP_PDUT_BVC_BLOCK_ACK: |
| case BSSGP_PDUT_BVC_UNBLOCK_ACK: |
| case BSSGP_PDUT_BVC_RESET: |
| 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: |
| /* FIXME: Some exception has occurred */ |
| LOGP(DGPRS, LOGL_NOTICE, |
| "NSEI=%u(SGSN) STATUS not implemented yet\n", nsvc->nsei); |
| 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) INVOKE TRACE not supported\n", nsvc->nsei); |
| break; |
| default: |
| DEBUGP(DGPRS, "BSSGP PDU type 0x%02x unknown\n", pdu_type); |
| break; |
| } |
| |
| return rc; |
| err_mand_ie: |
| ; /* FIXME: this would pull gprs_bssgp.c in, which in turn has dependencies */ |
| //return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg); |
| err_no_peer: |
| ; /* FIXME */ |
| } |
| |
| /* 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_NOTICE, "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; |
| } |