316 lines
8.6 KiB
C
316 lines
8.6 KiB
C
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/* NS-over-IP proxy */
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/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
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* (C) 2010 by On Waves
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <getopt.h>
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#include <errno.h>
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#include <sys/fcntl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <osmocore/talloc.h>
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#include <osmocore/select.h>
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#include <openbsc/signal.h>
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#include <openbsc/debug.h>
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#include <openbsc/gprs_ns.h>
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#include <openbsc/gprs_bssgp.h>
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struct gbprox_peer {
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struct llist_head list;
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/* NS-VC over which we send/receive data to this BVC */
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struct gprs_nsvc *nsvc;
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/* BVCI used for Point-to-Point to this peer */
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uint16_t bvci;
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/* Routeing Area that this peer is part of (raw 04.08 encoding) */
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uint8_t ra[6];
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};
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/* Linked list of all Gb peers (except SGSN) */
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static LLIST_HEAD(gbprox_bts_peers);
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/* Pointer to the SGSN peer */
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struct gbprox_peer *gbprox_peer_sgsn;
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/* The NS protocol stack instance we're using */
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extern struct gprs_ns_inst *gbprox_nsi;
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/* Find the gbprox_peer by its BVCI */
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static struct gbprox_peer *peer_by_bvci(uint16_t bvci)
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{
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struct gbprox_peer *peer;
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llist_for_each_entry(peer, &gbprox_bts_peers, list) {
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if (peer->bvci == bvci)
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return peer;
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}
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return NULL;
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}
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static struct gbprox_peer *peer_by_nsvc(struct gprs_nsvc *nsvc)
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{
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struct gbprox_peer *peer;
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llist_for_each_entry(peer, &gbprox_bts_peers, list) {
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if (peer->nsvc == nsvc)
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return peer;
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}
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return NULL;
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}
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/* look-up a peer by its Routeing Area Code (RAC) */
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static struct gbprox_peer *peer_by_rac(uint8_t *ra)
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{
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struct gbprox_peer *peer;
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llist_for_each_entry(peer, &gbprox_bts_peers, list) {
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if (!memcmp(&peer->ra, ra, 6))
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return peer;
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}
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return NULL;
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}
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/* look-up a peer by its Location Area Code (LAC) */
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static struct gbprox_peer *peer_by_lac(uint8_t *la)
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{
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struct gbprox_peer *peer;
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llist_for_each_entry(peer, &gbprox_bts_peers, list) {
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if (!memcmp(&peer->ra, la, 5))
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return peer;
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}
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return NULL;
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}
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static struct gbprox_peer *peer_alloc(uint16_t bvci)
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{
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struct gbprox_peer *peer;
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peer = talloc_zero(tall_bsc_ctx, struct gbprox_peer);
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if (!peer)
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return NULL;
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peer->bvci = bvci;
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llist_add(&peer->list, &gbprox_bts_peers);
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return peer;
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}
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static void peer_free(struct gbprox_peer *peer)
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{
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llist_del(&peer->list);
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talloc_free(peer);
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}
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/* feed a message down the NS-VC associated with the specified peer */
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static int gbprox_tx2peer(struct msgb *msg, struct gbprox_peer *peer,
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uint16_t ns_bvci)
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{
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msgb_bvci(msg) = ns_bvci;
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msgb_nsei(msg) = peer->nsvc->nsei;
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return gprs_ns_sendmsg(gbprox_nsi, msg);
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}
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/* Send a message to a peer identified by ptp_bvci but using ns_bvci
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* in the NS hdr */
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static int gbprox_tx2bvci(struct msgb *msg, uint16_t ptp_bvci,
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uint16_t ns_bvci)
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{
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struct gbprox_peer *peer;
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peer = peer_by_bvci(ptp_bvci);
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if (!peer)
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return -ENOENT;
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return gbprox_tx2peer(msg, peer, ns_bvci);
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}
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/* Receive an incoming signalling message from a BSS-side NS-VC */
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static int gbprox_rx_sig_from_bss(struct msgb *msg, struct gprs_nsvc *nsvc,
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uint16_t ns_bvci)
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{
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struct bssgp_normal_hdr *bgph = (struct bssgp_normal_hdr *) msg->l3h;
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struct tlv_parsed tp;
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uint8_t pdu_type = bgph->pdu_type;
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int data_len = msgb_l3len(msg) - sizeof(*bgph);
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struct gbprox_peer *from_peer;
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if (ns_bvci != 0) {
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LOGP(DGPRS, LOGL_NOTICE, "BVCI %u not signalling\n", ns_bvci);
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return -EINVAL;
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}
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/* we actually should never see those two for BVCI == 0, but double-check
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* just to make sure */
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if (pdu_type == BSSGP_PDUT_UL_UNITDATA ||
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pdu_type == BSSGP_PDUT_DL_UNITDATA) {
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LOGP(DGPRS, LOGL_NOTICE, "UNITDATA not allowed in signalling\n");
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return -EINVAL;
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}
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bssgp_tlv_parse(&tp, bgph->data, data_len);
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switch (pdu_type) {
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case BSSGP_PDUT_SUSPEND:
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case BSSGP_PDUT_RESUME:
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/* RAC snooping for SUSPEND/RESUME */
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if (!TLVP_PRESENT(&tp, BSSGP_IE_ROUTEING_AREA))
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goto err_mand_ie;
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from_peer = peer_by_nsvc(nsvc);
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if (!from_peer)
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goto err_no_peer;
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memcpy(&from_peer->ra, TLVP_VAL(&tp, BSSGP_IE_ROUTEING_AREA),
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sizeof(&from_peer->ra));
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/* FIXME: This only supports one BSS per RA */
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break;
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}
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/* Normally, we can simply pass on all signalling messages from BSS to SGSN */
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return gbprox_tx2peer(msg, gbprox_peer_sgsn, ns_bvci);
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err_no_peer:
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err_mand_ie:
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/* FIXME: do something */
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;
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}
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/* Receive paging request from SGSN, we need to relay to proper BSS */
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static int gbprox_rx_paging(struct msgb *msg, struct tlv_parsed *tp,
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struct gprs_nsvc *nsvc, uint16_t ns_bvci)
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{
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struct gbprox_peer *peer;
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if (TLVP_PRESENT(tp, BSSGP_IE_BVCI)) {
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uint16_t bvci = ntohs(*(uint16_t *)TLVP_VAL(tp, BSSGP_IE_BVCI));
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return gbprox_tx2bvci(msg, bvci, ns_bvci);
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} else if (TLVP_PRESENT(tp, BSSGP_IE_ROUTEING_AREA)) {
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peer = peer_by_rac(TLVP_VAL(tp, BSSGP_IE_ROUTEING_AREA));
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return gbprox_tx2peer(msg, peer, ns_bvci);
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} else if (TLVP_PRESENT(tp, BSSGP_IE_LOCATION_AREA)) {
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peer = peer_by_lac(TLVP_VAL(tp, BSSGP_IE_LOCATION_AREA));
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return gbprox_tx2peer(msg, peer, ns_bvci);
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} else
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return -EINVAL;
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}
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/* Receive an incoming signalling message from the SGSN-side NS-VC */
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static int gbprox_rx_sig_from_sgsn(struct msgb *msg, struct gprs_nsvc *nsvc,
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uint16_t ns_bvci)
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{
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struct bssgp_normal_hdr *bgph = (struct bssgp_normal_hdr *) msg->l3h;
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struct tlv_parsed tp;
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uint8_t pdu_type = bgph->pdu_type;
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int data_len = msgb_l3len(msg) - sizeof(*bgph);
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struct gbprox_peer *peer;
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uint16_t bvci;
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int rc = 0;
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if (ns_bvci != 0) {
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LOGP(DGPRS, LOGL_NOTICE, "BVCI %u not signalling\n", ns_bvci);
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return -EINVAL;
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}
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/* we actually should never see those two for BVCI == 0, but double-check
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* just to make sure */
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if (pdu_type == BSSGP_PDUT_UL_UNITDATA ||
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pdu_type == BSSGP_PDUT_DL_UNITDATA) {
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LOGP(DGPRS, LOGL_NOTICE, "UNITDATA not allowed in signalling\n");
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return -EINVAL;
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}
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rc = bssgp_tlv_parse(&tp, bgph->data, data_len);
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switch (pdu_type) {
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case BSSGP_PDUT_FLUSH_LL:
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case BSSGP_PDUT_BVC_BLOCK_ACK:
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case BSSGP_PDUT_BVC_UNBLOCK_ACK:
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case BSSGP_PDUT_BVC_RESET:
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case BSSGP_PDUT_BVC_RESET_ACK:
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/* simple case: BVCI IE is mandatory */
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if (!TLVP_PRESENT(&tp, BSSGP_IE_BVCI))
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goto err_mand_ie;
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bvci = ntohs(*(uint16_t *)TLVP_VAL(&tp, BSSGP_IE_BVCI));
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rc = gbprox_tx2bvci(msg, bvci, ns_bvci);
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break;
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case BSSGP_PDUT_PAGING_PS:
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case BSSGP_PDUT_PAGING_CS:
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/* process the paging request (LAC/RAC lookup) */
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rc = gbprox_rx_paging(msg, &tp, nsvc, ns_bvci);
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break;
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case BSSGP_PDUT_STATUS:
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/* FIXME: Some exception has occurred */
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LOGP(DGPRS, LOGL_NOTICE, "STATUS not implemented yet\n");
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break;
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/* those only exist in the SGSN -> BSS direction */
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case BSSGP_PDUT_SUSPEND_ACK:
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case BSSGP_PDUT_SUSPEND_NACK:
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case BSSGP_PDUT_RESUME_ACK:
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case BSSGP_PDUT_RESUME_NACK:
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/* RAC IE is mandatory */
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if (!TLVP_PRESENT(&tp, BSSGP_IE_ROUTEING_AREA))
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goto err_mand_ie;
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peer = peer_by_rac(TLVP_VAL(&tp, BSSGP_IE_ROUTEING_AREA));
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if (!peer)
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goto err_no_peer;
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rc = gbprox_tx2peer(msg, peer, ns_bvci);
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break;
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case BSSGP_PDUT_SGSN_INVOKE_TRACE:
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LOGP(DGPRS, LOGL_ERROR, "SGSN INVOKE TRACE not supported\n");
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break;
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default:
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DEBUGP(DGPRS, "BSSGP PDU type 0x%02x unknown\n", pdu_type);
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break;
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}
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return rc;
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err_mand_ie:
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; /* FIXME: this would pull gprs_bssgp.c in, which in turn has dependencies */
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//return bssgp_tx_status(BSSGP_CAUSE_MISSING_MAND_IE, NULL, msg);
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err_no_peer:
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; /* FIXME */
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}
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/* Main input function for Gb proxy */
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int gbprox_rcvmsg(struct msgb *msg, struct gprs_nsvc *nsvc, uint16_t ns_bvci)
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{
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struct gbprox_peer *peer;
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/* Only BVCI=0 messages need special treatment */
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if (ns_bvci == 0 || ns_bvci == 1) {
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if (nsvc->remote_end_is_sgsn)
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return gbprox_rx_sig_from_sgsn(msg, nsvc, ns_bvci);
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else
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return gbprox_rx_sig_from_bss(msg, nsvc, ns_bvci);
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}
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/* All other BVCI are PTP and thus can be simply forwarded */
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peer = peer_by_bvci(ns_bvci);
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if (!peer) {
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LOGP(DGPRS, LOGL_ERROR, "Couldn't find peer for BVCI %u\n", ns_bvci);
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return -EIO;
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}
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return gbprox_tx2peer(msg, peer, ns_bvci);
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}
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