250 lines
6.9 KiB
C
250 lines
6.9 KiB
C
/* SCCP patching and handling routines */
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/*
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* (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.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 Affero General Public License as published by
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* the Free Software Foundation; either version 3 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 Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <openbsc/debug.h>
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#include <openbsc/bsc_nat.h>
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#include <openbsc/bsc_nat_sccp.h>
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#include <osmocom/sccp/sccp.h>
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#include <osmocom/core/talloc.h>
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#include <string.h>
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#include <time.h>
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static int equal(struct sccp_source_reference *ref1, struct sccp_source_reference *ref2)
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{
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return memcmp(ref1, ref2, sizeof(*ref1)) == 0;
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}
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/*
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* SCCP patching below
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*/
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/* check if we are using this ref for patched already */
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static int sccp_ref_is_free(struct sccp_source_reference *ref, struct bsc_nat *nat)
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{
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struct sccp_connections *conn;
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llist_for_each_entry(conn, &nat->sccp_connections, list_entry) {
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if (memcmp(ref, &conn->patched_ref, sizeof(*ref)) == 0)
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return -1;
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}
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return 0;
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}
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/* copied from sccp.c */
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static int assign_src_local_reference(struct sccp_source_reference *ref, struct bsc_nat *nat)
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{
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static uint32_t last_ref = 0x50000;
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int wrapped = 0;
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do {
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struct sccp_source_reference reference;
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reference.octet1 = (last_ref >> 0) & 0xff;
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reference.octet2 = (last_ref >> 8) & 0xff;
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reference.octet3 = (last_ref >> 16) & 0xff;
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++last_ref;
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/* do not use the reversed word and wrap around */
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if ((last_ref & 0x00FFFFFF) == 0x00FFFFFF) {
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LOGP(DNAT, LOGL_NOTICE, "Wrapped searching for a free code\n");
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last_ref = 0;
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++wrapped;
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}
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if (sccp_ref_is_free(&reference, nat) == 0) {
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*ref = reference;
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return 0;
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}
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} while (wrapped != 2);
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LOGP(DNAT, LOGL_ERROR, "Finding a free reference failed\n");
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return -1;
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}
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struct sccp_connections *create_sccp_src_ref(struct bsc_connection *bsc,
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struct bsc_nat_parsed *parsed)
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{
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struct sccp_connections *conn;
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/* Some commercial BSCs like to reassign there SRC ref */
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llist_for_each_entry(conn, &bsc->nat->sccp_connections, list_entry) {
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if (conn->bsc != bsc)
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continue;
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if (memcmp(&conn->real_ref, parsed->src_local_ref, sizeof(conn->real_ref)) != 0)
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continue;
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/* the BSC has reassigned the SRC ref and we failed to keep track */
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memset(&conn->remote_ref, 0, sizeof(conn->remote_ref));
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if (assign_src_local_reference(&conn->patched_ref, bsc->nat) != 0) {
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LOGP(DNAT, LOGL_ERROR, "BSC %d reused src ref: %d and we failed to generate a new id.\n",
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bsc->cfg->nr, sccp_src_ref_to_int(parsed->src_local_ref));
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bsc_mgcp_dlcx(conn);
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llist_del(&conn->list_entry);
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talloc_free(conn);
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return NULL;
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} else {
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clock_gettime(CLOCK_MONOTONIC, &conn->creation_time);
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bsc_mgcp_dlcx(conn);
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return conn;
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}
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}
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conn = talloc_zero(bsc->nat, struct sccp_connections);
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if (!conn) {
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LOGP(DNAT, LOGL_ERROR, "Memory allocation failure.\n");
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return NULL;
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}
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conn->bsc = bsc;
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clock_gettime(CLOCK_MONOTONIC, &conn->creation_time);
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conn->real_ref = *parsed->src_local_ref;
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if (assign_src_local_reference(&conn->patched_ref, bsc->nat) != 0) {
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LOGP(DNAT, LOGL_ERROR, "Failed to assign a ref.\n");
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talloc_free(conn);
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return NULL;
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}
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bsc_mgcp_init(conn);
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llist_add_tail(&conn->list_entry, &bsc->nat->sccp_connections);
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rate_ctr_inc(&bsc->cfg->stats.ctrg->ctr[BCFG_CTR_SCCP_CONN]);
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osmo_counter_inc(bsc->cfg->nat->stats.sccp.conn);
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LOGP(DNAT, LOGL_DEBUG, "Created 0x%x <-> 0x%x mapping for con %p\n",
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sccp_src_ref_to_int(&conn->real_ref),
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sccp_src_ref_to_int(&conn->patched_ref), bsc);
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return conn;
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}
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int update_sccp_src_ref(struct sccp_connections *sccp, struct bsc_nat_parsed *parsed)
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{
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if (!parsed->dest_local_ref || !parsed->src_local_ref) {
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LOGP(DNAT, LOGL_ERROR, "CC MSG should contain both local and dest address.\n");
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return -1;
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}
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sccp->remote_ref = *parsed->src_local_ref;
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sccp->has_remote_ref = 1;
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LOGP(DNAT, LOGL_DEBUG, "Updating 0x%x to remote 0x%x on %p\n",
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sccp_src_ref_to_int(&sccp->patched_ref),
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sccp_src_ref_to_int(&sccp->remote_ref), sccp->bsc);
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return 0;
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}
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void remove_sccp_src_ref(struct bsc_connection *bsc, struct msgb *msg, struct bsc_nat_parsed *parsed)
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{
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struct sccp_connections *conn;
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llist_for_each_entry(conn, &bsc->nat->sccp_connections, list_entry) {
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if (memcmp(parsed->src_local_ref,
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&conn->patched_ref, sizeof(conn->patched_ref)) == 0) {
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sccp_connection_destroy(conn);
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return;
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}
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}
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LOGP(DNAT, LOGL_ERROR, "Can not remove connection: 0x%x\n",
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sccp_src_ref_to_int(parsed->src_local_ref));
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}
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/*
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* We have a message from the MSC to the BSC. The MSC is using
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* an address that was assigned by the MUX, we need to update the
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* dest reference to the real network.
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*/
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struct sccp_connections *patch_sccp_src_ref_to_bsc(struct msgb *msg,
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struct bsc_nat_parsed *parsed,
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struct bsc_nat *nat)
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{
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struct sccp_connections *conn;
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if (!parsed->dest_local_ref) {
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LOGP(DNAT, LOGL_ERROR, "MSG should contain dest_local_ref.\n");
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return NULL;
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}
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llist_for_each_entry(conn, &nat->sccp_connections, list_entry) {
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if (!equal(parsed->dest_local_ref, &conn->patched_ref))
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continue;
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/* Change the dest address to the real one */
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*parsed->dest_local_ref = conn->real_ref;
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return conn;
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}
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return NULL;
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}
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/*
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* These are message to the MSC. We will need to find the BSC
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* Connection by either the SRC or the DST local reference.
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*
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* In case of a CR we need to work by the SRC local reference
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* in all other cases we need to work by the destination local
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* reference..
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*/
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struct sccp_connections *patch_sccp_src_ref_to_msc(struct msgb *msg,
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struct bsc_nat_parsed *parsed,
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struct bsc_connection *bsc)
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{
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struct sccp_connections *conn;
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llist_for_each_entry(conn, &bsc->nat->sccp_connections, list_entry) {
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if (conn->bsc != bsc)
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continue;
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if (parsed->src_local_ref) {
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if (equal(parsed->src_local_ref, &conn->real_ref)) {
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*parsed->src_local_ref = conn->patched_ref;
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return conn;
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}
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} else if (parsed->dest_local_ref) {
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if (equal(parsed->dest_local_ref, &conn->remote_ref))
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return conn;
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} else {
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LOGP(DNAT, LOGL_ERROR, "Header has neither loc/dst ref.\n");
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return NULL;
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}
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}
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return NULL;
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}
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struct sccp_connections *bsc_nat_find_con_by_bsc(struct bsc_nat *nat,
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struct sccp_source_reference *ref)
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{
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struct sccp_connections *conn;
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llist_for_each_entry(conn, &nat->sccp_connections, list_entry) {
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if (memcmp(ref, &conn->real_ref, sizeof(*ref)) == 0)
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return conn;
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}
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return NULL;
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}
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