| /* SCCP patching and handling routines */ |
| /* |
| * (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.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 <openbsc/debug.h> |
| #include <openbsc/bsc_nat.h> |
| |
| #include <sccp/sccp.h> |
| |
| #include <osmocore/talloc.h> |
| |
| #include <string.h> |
| |
| static int equal(struct sccp_source_reference *ref1, struct sccp_source_reference *ref2) |
| { |
| return memcmp(ref1, ref2, sizeof(*ref1)) == 0; |
| } |
| |
| /* |
| * SCCP patching below |
| */ |
| |
| /* check if we are using this ref for patched already */ |
| static int sccp_ref_is_free(struct sccp_source_reference *ref, struct bsc_nat *nat) |
| { |
| struct sccp_connections *conn; |
| |
| llist_for_each_entry(conn, &nat->sccp_connections, list_entry) { |
| if (memcmp(ref, &conn->patched_ref, sizeof(*ref)) == 0) |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* copied from sccp.c */ |
| static int assign_src_local_reference(struct sccp_source_reference *ref, struct bsc_nat *nat) |
| { |
| static u_int32_t last_ref = 0x50000; |
| int wrapped = 0; |
| |
| do { |
| struct sccp_source_reference reference; |
| reference.octet1 = (last_ref >> 0) & 0xff; |
| reference.octet2 = (last_ref >> 8) & 0xff; |
| reference.octet3 = (last_ref >> 16) & 0xff; |
| |
| ++last_ref; |
| /* do not use the reversed word and wrap around */ |
| if ((last_ref & 0x00FFFFFF) == 0x00FFFFFF) { |
| LOGP(DNAT, LOGL_NOTICE, "Wrapped searching for a free code\n"); |
| last_ref = 0; |
| ++wrapped; |
| } |
| |
| if (sccp_ref_is_free(&reference, nat) == 0) { |
| *ref = reference; |
| return 0; |
| } |
| } while (wrapped != 2); |
| |
| LOGP(DNAT, LOGL_ERROR, "Finding a free reference failed\n"); |
| return -1; |
| } |
| |
| int create_sccp_src_ref(struct bsc_connection *bsc, struct msgb *msg, struct bsc_nat_parsed *parsed) |
| { |
| struct sccp_connections *conn; |
| |
| conn = talloc_zero(bsc->nat, struct sccp_connections); |
| if (!conn) { |
| LOGP(DNAT, LOGL_ERROR, "Memory allocation failure.\n"); |
| return -1; |
| } |
| |
| conn->bsc = bsc; |
| conn->real_ref = *parsed->src_local_ref; |
| if (assign_src_local_reference(&conn->patched_ref, bsc->nat) != 0) { |
| LOGP(DNAT, LOGL_ERROR, "Failed to assign a ref.\n"); |
| talloc_free(conn); |
| return -1; |
| } |
| |
| llist_add(&conn->list_entry, &bsc->nat->sccp_connections); |
| |
| LOGP(DNAT, LOGL_DEBUG, "Created 0x%x <-> 0x%x mapping for con %p\n", |
| sccp_src_ref_to_int(&conn->real_ref), |
| sccp_src_ref_to_int(&conn->patched_ref), bsc); |
| |
| return 0; |
| } |
| |
| int update_sccp_src_ref(struct sccp_connections *sccp, struct bsc_nat_parsed *parsed) |
| { |
| if (!parsed->dest_local_ref || !parsed->src_local_ref) { |
| LOGP(DNAT, LOGL_ERROR, "CC MSG should contain both local and dest address.\n"); |
| return -1; |
| } |
| |
| sccp->remote_ref = *parsed->src_local_ref; |
| LOGP(DNAT, LOGL_DEBUG, "Updating 0x%x to remote 0x%x on %p\n", |
| sccp_src_ref_to_int(&sccp->patched_ref), |
| sccp_src_ref_to_int(&sccp->remote_ref), sccp->bsc); |
| |
| return 0; |
| } |
| |
| void remove_sccp_src_ref(struct bsc_connection *bsc, struct msgb *msg, struct bsc_nat_parsed *parsed) |
| { |
| struct sccp_connections *conn; |
| |
| llist_for_each_entry(conn, &bsc->nat->sccp_connections, list_entry) { |
| if (memcmp(parsed->src_local_ref, |
| &conn->real_ref, sizeof(conn->real_ref)) == 0) { |
| |
| /* two BSCs have used the same real ref... this is why we rewrite it */ |
| if (bsc != conn->bsc) |
| continue; |
| |
| sccp_connection_destroy(conn); |
| return; |
| } |
| } |
| |
| LOGP(DNAT, LOGL_ERROR, "Unknown connection.\n"); |
| } |
| |
| /* |
| * We have a message from the MSC to the BSC. The MSC is using |
| * an address that was assigned by the MUX, we need to update the |
| * dest reference to the real network. |
| */ |
| struct sccp_connections *patch_sccp_src_ref_to_bsc(struct msgb *msg, |
| struct bsc_nat_parsed *parsed, |
| struct bsc_nat *nat) |
| { |
| struct sccp_connections *conn; |
| |
| if (!parsed->dest_local_ref) { |
| LOGP(DNAT, LOGL_ERROR, "MSG should contain dest_local_ref.\n"); |
| return NULL; |
| } |
| |
| |
| llist_for_each_entry(conn, &nat->sccp_connections, list_entry) { |
| if (!equal(parsed->dest_local_ref, &conn->patched_ref)) |
| continue; |
| |
| /* Change the dest address to the real one */ |
| *parsed->dest_local_ref = conn->real_ref; |
| return conn; |
| } |
| |
| return NULL; |
| } |
| |
| /* |
| * These are message to the MSC. We will need to find the BSC |
| * Connection by either the SRC or the DST local reference. |
| * |
| * In case of a CR we need to work by the SRC local reference |
| * in all other cases we need to work by the destination local |
| * reference.. |
| */ |
| struct sccp_connections *patch_sccp_src_ref_to_msc(struct msgb *msg, |
| struct bsc_nat_parsed *parsed, |
| struct bsc_nat *nat) |
| { |
| struct sccp_connections *conn; |
| |
| llist_for_each_entry(conn, &nat->sccp_connections, list_entry) { |
| if (parsed->src_local_ref) { |
| if (equal(parsed->src_local_ref, &conn->real_ref)) { |
| *parsed->src_local_ref = conn->patched_ref; |
| return conn; |
| } |
| } else if (parsed->dest_local_ref) { |
| if (equal(parsed->dest_local_ref, &conn->remote_ref)) |
| return conn; |
| } else { |
| LOGP(DNAT, LOGL_ERROR, "Header has neither loc/dst ref.\n"); |
| return NULL; |
| } |
| } |
| |
| return NULL; |
| } |