diff options
Diffstat (limited to 'openbsc/src/nat/bsc_sccp.c')
| -rw-r--r-- | openbsc/src/nat/bsc_sccp.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/openbsc/src/nat/bsc_sccp.c b/openbsc/src/nat/bsc_sccp.c new file mode 100644 index 000000000..e76d52268 --- /dev/null +++ b/openbsc/src/nat/bsc_sccp.c @@ -0,0 +1,203 @@ +/* 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->patched_ref, sizeof(conn->patched_ref)) == 0) { + + sccp_connection_destroy(conn); + return; + } + } + + LOGP(DNAT, LOGL_ERROR, "Can not remove connection: 0x%x\n", + sccp_src_ref_to_int(parsed->src_local_ref)); +} + +/* + * 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; +} + |