| |
| /* BSC Multiplexer/NAT Utilities */ |
| |
| /* |
| * (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/bsc_nat.h> |
| #include <openbsc/bsc_nat_sccp.h> |
| #include <openbsc/bsc_msc.h> |
| #include <openbsc/gsm_data.h> |
| #include <openbsc/debug.h> |
| #include <openbsc/ipaccess.h> |
| |
| #include <osmocore/linuxlist.h> |
| #include <osmocore/talloc.h> |
| #include <osmocore/gsm0808.h> |
| |
| #include <osmocore/protocol/gsm_08_08.h> |
| |
| #include <osmocom/sccp/sccp.h> |
| |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| |
| |
| static const struct rate_ctr_desc bsc_cfg_ctr_description[] = { |
| [BCFG_CTR_SCCP_CONN] = { "sccp.conn", "SCCP Connections "}, |
| [BCFG_CTR_SCCP_CALLS] = { "sccp.calls", "SCCP Assignment Commands "}, |
| [BCFG_CTR_NET_RECONN] = { "net.reconnects", "Network reconnects "}, |
| [BCFG_CTR_DROPPED_SCCP] = { "dropped.sccp", "Dropped SCCP connections."}, |
| [BCFG_CTR_DROPPED_CALLS] = { "dropped.calls", "Dropped active calls. "}, |
| }; |
| |
| static const struct rate_ctr_group_desc bsc_cfg_ctrg_desc = { |
| .group_name_prefix = "nat.bsc", |
| .group_description = "NAT BSC Statistics", |
| .num_ctr = ARRAY_SIZE(bsc_cfg_ctr_description), |
| .ctr_desc = bsc_cfg_ctr_description, |
| }; |
| |
| struct bsc_nat *bsc_nat_alloc(void) |
| { |
| struct bsc_nat *nat = talloc_zero(tall_bsc_ctx, struct bsc_nat); |
| if (!nat) |
| return NULL; |
| |
| INIT_LLIST_HEAD(&nat->sccp_connections); |
| INIT_LLIST_HEAD(&nat->bsc_connections); |
| INIT_LLIST_HEAD(&nat->bsc_configs); |
| INIT_LLIST_HEAD(&nat->access_lists); |
| |
| nat->stats.sccp.conn = counter_alloc("nat.sccp.conn"); |
| nat->stats.sccp.calls = counter_alloc("nat.sccp.calls"); |
| nat->stats.bsc.reconn = counter_alloc("nat.bsc.conn"); |
| nat->stats.bsc.auth_fail = counter_alloc("nat.bsc.auth_fail"); |
| nat->stats.msc.reconn = counter_alloc("nat.msc.conn"); |
| nat->msc_ip = talloc_strdup(nat, "127.0.0.1"); |
| nat->msc_port = 5000; |
| nat->auth_timeout = 2; |
| nat->ping_timeout = 20; |
| nat->pong_timeout = 5; |
| return nat; |
| } |
| |
| void bsc_nat_set_msc_ip(struct bsc_nat *nat, const char *ip) |
| { |
| if (nat->msc_ip) |
| talloc_free(nat->msc_ip); |
| nat->msc_ip = talloc_strdup(nat, ip); |
| } |
| |
| struct bsc_connection *bsc_connection_alloc(struct bsc_nat *nat) |
| { |
| struct bsc_connection *con = talloc_zero(nat, struct bsc_connection); |
| if (!con) |
| return NULL; |
| |
| con->nat = nat; |
| write_queue_init(&con->write_queue, 100); |
| return con; |
| } |
| |
| struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token, unsigned int lac) |
| { |
| struct bsc_config *conf = talloc_zero(nat, struct bsc_config); |
| if (!conf) |
| return NULL; |
| |
| conf->token = talloc_strdup(conf, token); |
| conf->lac = lac; |
| conf->nr = nat->num_bsc; |
| conf->nat = nat; |
| |
| llist_add_tail(&conf->entry, &nat->bsc_configs); |
| ++nat->num_bsc; |
| |
| conf->stats.ctrg = rate_ctr_group_alloc(conf, &bsc_cfg_ctrg_desc, conf->lac); |
| if (!conf->stats.ctrg) { |
| talloc_free(conf); |
| return NULL; |
| } |
| |
| return conf; |
| } |
| |
| void sccp_connection_destroy(struct sccp_connections *conn) |
| { |
| LOGP(DNAT, LOGL_DEBUG, "Destroy 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), conn->bsc); |
| bsc_mgcp_dlcx(conn); |
| llist_del(&conn->list_entry); |
| talloc_free(conn); |
| } |
| |
| struct bsc_connection *bsc_nat_find_bsc(struct bsc_nat *nat, struct msgb *msg, int *lac_out) |
| { |
| struct bsc_connection *bsc; |
| int data_length; |
| const uint8_t *data; |
| struct tlv_parsed tp; |
| int i = 0; |
| |
| *lac_out = -1; |
| |
| if (!msg->l3h || msgb_l3len(msg) < 3) { |
| LOGP(DNAT, LOGL_ERROR, "Paging message is too short.\n"); |
| return NULL; |
| } |
| |
| tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l3h + 3, msgb_l3len(msg) - 3, 0, 0); |
| if (!TLVP_PRESENT(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST)) { |
| LOGP(DNAT, LOGL_ERROR, "No CellIdentifier List inside paging msg.\n"); |
| return NULL; |
| } |
| |
| data_length = TLVP_LEN(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST); |
| data = TLVP_VAL(&tp, GSM0808_IE_CELL_IDENTIFIER_LIST); |
| |
| /* No need to try a different BSS */ |
| if (data[0] == CELL_IDENT_BSS) { |
| return NULL; |
| } else if (data[0] != CELL_IDENT_LAC) { |
| LOGP(DNAT, LOGL_ERROR, "Unhandled cell ident discrminator: %d\n", data[0]); |
| return NULL; |
| } |
| |
| /* Currently we only handle one BSC */ |
| for (i = 1; i < data_length - 1; i += 2) { |
| unsigned int _lac = ntohs(*(unsigned int *) &data[i]); |
| *lac_out = _lac; |
| llist_for_each_entry(bsc, &nat->bsc_connections, list_entry) { |
| if (!bsc->cfg) |
| continue; |
| if (!bsc->authenticated || _lac != bsc->cfg->lac) |
| continue; |
| |
| return bsc; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| int bsc_write_mgcp(struct bsc_connection *bsc, const uint8_t *data, unsigned int length) |
| { |
| struct msgb *msg; |
| |
| if (length > 4096 - 128) { |
| LOGP(DINP, LOGL_ERROR, "Can not send message of that size.\n"); |
| return -1; |
| } |
| |
| msg = msgb_alloc_headroom(4096, 128, "to-bsc"); |
| if (!msg) { |
| LOGP(DINP, LOGL_ERROR, "Failed to allocate memory for BSC msg.\n"); |
| return -1; |
| } |
| |
| /* copy the data */ |
| msg->l3h = msgb_put(msg, length); |
| memcpy(msg->l3h, data, length); |
| |
| return bsc_write(bsc, msg, NAT_IPAC_PROTO_MGCP); |
| } |
| |
| int bsc_write(struct bsc_connection *bsc, struct msgb *msg, int proto) |
| { |
| /* prepend the header */ |
| ipaccess_prepend_header(msg, proto); |
| |
| if (write_queue_enqueue(&bsc->write_queue, msg) != 0) { |
| LOGP(DINP, LOGL_ERROR, "Failed to enqueue the write.\n"); |
| msgb_free(msg); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| static int lst_check_allow(struct bsc_nat_acc_lst *lst, const char *mi_string) |
| { |
| struct bsc_nat_acc_lst_entry *entry; |
| |
| llist_for_each_entry(entry, &lst->fltr_list, list) { |
| if (!entry->imsi_allow) |
| continue; |
| if (regexec(&entry->imsi_allow_re, mi_string, 0, NULL, 0) == 0) |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| static int lst_check_deny(struct bsc_nat_acc_lst *lst, const char *mi_string) |
| { |
| struct bsc_nat_acc_lst_entry *entry; |
| |
| llist_for_each_entry(entry, &lst->fltr_list, list) { |
| if (!entry->imsi_deny) |
| continue; |
| if (regexec(&entry->imsi_deny_re, mi_string, 0, NULL, 0) == 0) |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| /* apply white/black list */ |
| static int auth_imsi(struct bsc_connection *bsc, const char *mi_string) |
| { |
| /* |
| * Now apply blacklist/whitelist of the BSC and the NAT. |
| * 1.) Reject if the IMSI is not allowed at the BSC |
| * 2.) Allow directly if the IMSI is allowed at the BSC |
| * 3.) Reject if the IMSI not allowed at the global level. |
| * 4.) Allow directly if the IMSI is allowed at the global level |
| */ |
| struct bsc_nat_acc_lst *nat_lst = NULL; |
| struct bsc_nat_acc_lst *bsc_lst = NULL; |
| |
| bsc_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->cfg->acc_lst_name); |
| nat_lst = bsc_nat_acc_lst_find(bsc->nat, bsc->nat->acc_lst_name); |
| |
| |
| if (bsc_lst) { |
| /* 1. BSC deny */ |
| if (lst_check_deny(bsc_lst, mi_string) == 0) { |
| LOGP(DNAT, LOGL_ERROR, |
| "Filtering %s by imsi_deny on bsc nr: %d.\n", mi_string, bsc->cfg->nr); |
| return -2; |
| } |
| |
| /* 2. BSC allow */ |
| if (lst_check_allow(bsc_lst, mi_string) == 0) |
| return 1; |
| } |
| |
| /* 3. NAT deny */ |
| if (nat_lst) { |
| if (lst_check_deny(nat_lst, mi_string) == 0) { |
| LOGP(DNAT, LOGL_ERROR, |
| "Filtering %s by nat imsi_deny on bsc nr: %d.\n", mi_string, bsc->cfg->nr); |
| return -3; |
| } |
| } |
| |
| return 1; |
| } |
| |
| static int _cr_check_loc_upd(struct bsc_connection *bsc, uint8_t *data, unsigned int length) |
| { |
| uint8_t mi_type; |
| struct gsm48_loc_upd_req *lu; |
| char mi_string[GSM48_MI_SIZE]; |
| |
| if (length < sizeof(*lu)) { |
| LOGP(DNAT, LOGL_ERROR, |
| "LU does not fit. Length is %d \n", length); |
| return -1; |
| } |
| |
| lu = (struct gsm48_loc_upd_req *) data; |
| mi_type = lu->mi[0] & GSM_MI_TYPE_MASK; |
| |
| /* |
| * We can only deal with the IMSI. This will fail for a phone that |
| * will send the TMSI of a previous network to us. |
| */ |
| if (mi_type != GSM_MI_TYPE_IMSI) |
| return 0; |
| |
| gsm48_mi_to_string(mi_string, sizeof(mi_string), lu->mi, lu->mi_len); |
| return auth_imsi(bsc, mi_string); |
| } |
| |
| static int _cr_check_cm_serv_req(struct bsc_connection *bsc, uint8_t *data, unsigned int length) |
| { |
| static const uint32_t classmark_offset = |
| offsetof(struct gsm48_service_request, classmark); |
| |
| char mi_string[GSM48_MI_SIZE]; |
| uint8_t mi_type; |
| int rc; |
| struct gsm48_service_request *req; |
| |
| /* unfortunately in Phase1 the classmark2 length is variable */ |
| |
| if (length < sizeof(*req)) { |
| LOGP(DNAT, LOGL_ERROR, |
| "CM Serv Req does not fit. Length is %d\n", length); |
| return -1; |
| } |
| |
| req = (struct gsm48_service_request *) data; |
| rc = gsm48_extract_mi((uint8_t *) &req->classmark, |
| length - classmark_offset, mi_string, &mi_type); |
| if (rc < 0) { |
| LOGP(DNAT, LOGL_ERROR, "Failed to parse the classmark2/mi. error: %d\n", rc); |
| return -1; |
| } |
| |
| /* we have to let the TMSI or such pass */ |
| if (mi_type != GSM_MI_TYPE_IMSI) |
| return 0; |
| |
| return auth_imsi(bsc, mi_string); |
| } |
| |
| static int _cr_check_pag_resp(struct bsc_connection *bsc, uint8_t *data, unsigned int length) |
| { |
| struct gsm48_pag_resp *resp; |
| char mi_string[GSM48_MI_SIZE]; |
| uint8_t mi_type; |
| |
| if (length < sizeof(*resp)) { |
| LOGP(DNAT, LOGL_ERROR, "PAG RESP does not fit. Length was %d.\n", length); |
| return -1; |
| } |
| |
| resp = (struct gsm48_pag_resp *) data; |
| if (gsm48_paging_extract_mi(resp, length, mi_string, &mi_type) < 0) { |
| LOGP(DNAT, LOGL_ERROR, "Failed to extract the MI.\n"); |
| return -1; |
| } |
| |
| /* we need to let it pass for now */ |
| if (mi_type != GSM_MI_TYPE_IMSI) |
| return 0; |
| |
| return auth_imsi(bsc, mi_string); |
| } |
| |
| static int _dt_check_id_resp(struct bsc_connection *bsc, |
| uint8_t *data, unsigned int length, |
| struct sccp_connections *con) |
| { |
| char mi_string[GSM48_MI_SIZE]; |
| uint8_t mi_type; |
| int ret; |
| |
| if (length < 2) { |
| LOGP(DNAT, LOGL_ERROR, "mi does not fit.\n"); |
| return -1; |
| } |
| |
| if (data[0] < length - 1) { |
| LOGP(DNAT, LOGL_ERROR, "mi length too big.\n"); |
| return -2; |
| } |
| |
| mi_type = data[1] & GSM_MI_TYPE_MASK; |
| gsm48_mi_to_string(mi_string, sizeof(mi_string), &data[1], data[0]); |
| |
| if (mi_type != GSM_MI_TYPE_IMSI) |
| return 0; |
| |
| ret = auth_imsi(bsc, mi_string); |
| con->imsi_checked = 1; |
| return ret; |
| } |
| |
| /* Filter out CR data... */ |
| int bsc_nat_filter_sccp_cr(struct bsc_connection *bsc, struct msgb *msg, struct bsc_nat_parsed *parsed, int *con_type) |
| { |
| struct tlv_parsed tp; |
| struct gsm48_hdr *hdr48; |
| int hdr48_len; |
| int len; |
| uint8_t msg_type; |
| |
| *con_type = NAT_CON_TYPE_NONE; |
| |
| if (parsed->gsm_type != BSS_MAP_MSG_COMPLETE_LAYER_3) { |
| LOGP(DNAT, LOGL_ERROR, |
| "Rejecting CR message due wrong GSM Type %d\n", parsed->gsm_type); |
| return -1; |
| } |
| |
| /* the parsed has had some basic l3 length check */ |
| len = msg->l3h[1]; |
| if (msgb_l3len(msg) - 3 < len) { |
| LOGP(DNAT, LOGL_ERROR, |
| "The CR Data has not enough space...\n"); |
| return -1; |
| } |
| |
| msg->l4h = &msg->l3h[3]; |
| len -= 1; |
| |
| tlv_parse(&tp, gsm0808_att_tlvdef(), msg->l4h, len, 0, 0); |
| |
| if (!TLVP_PRESENT(&tp, GSM0808_IE_LAYER_3_INFORMATION)) { |
| LOGP(DNAT, LOGL_ERROR, "CR Data does not contain layer3 information.\n"); |
| return -1; |
| } |
| |
| hdr48_len = TLVP_LEN(&tp, GSM0808_IE_LAYER_3_INFORMATION); |
| |
| if (hdr48_len < sizeof(*hdr48)) { |
| LOGP(DNAT, LOGL_ERROR, "GSM48 header does not fit.\n"); |
| return -1; |
| } |
| |
| hdr48 = (struct gsm48_hdr *) TLVP_VAL(&tp, GSM0808_IE_LAYER_3_INFORMATION); |
| |
| msg_type = hdr48->msg_type & 0xbf; |
| if (hdr48->proto_discr == GSM48_PDISC_MM && |
| msg_type == GSM48_MT_MM_LOC_UPD_REQUEST) { |
| *con_type = NAT_CON_TYPE_LU; |
| return _cr_check_loc_upd(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48)); |
| } else if (hdr48->proto_discr == GSM48_PDISC_MM && |
| msg_type == GSM48_MT_MM_CM_SERV_REQ) { |
| *con_type = NAT_CON_TYPE_CM_SERV_REQ; |
| return _cr_check_cm_serv_req(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48)); |
| } else if (hdr48->proto_discr == GSM48_PDISC_RR && |
| msg_type == GSM48_MT_RR_PAG_RESP) { |
| *con_type = NAT_CON_TYPE_PAG_RESP; |
| return _cr_check_pag_resp(bsc, &hdr48->data[0], hdr48_len - sizeof(*hdr48)); |
| } else { |
| /* We only want to filter the above, let other things pass */ |
| *con_type = NAT_CON_TYPE_OTHER; |
| return 0; |
| } |
| } |
| |
| int bsc_nat_filter_dt(struct bsc_connection *bsc, struct msgb *msg, |
| struct sccp_connections *con, struct bsc_nat_parsed *parsed) |
| { |
| uint32_t len; |
| uint8_t msg_type; |
| struct gsm48_hdr *hdr48; |
| |
| if (con->imsi_checked) |
| return 0; |
| |
| /* only care about DTAP messages */ |
| if (parsed->bssap != BSSAP_MSG_DTAP) |
| return 0; |
| |
| /* gsm_type is actually the size of the dtap */ |
| len = parsed->gsm_type; |
| if (len < msgb_l3len(msg) - 3) { |
| LOGP(DNAT, LOGL_ERROR, "Not enough space for DTAP.\n"); |
| return -1; |
| } |
| |
| if (len < sizeof(*hdr48)) { |
| LOGP(DNAT, LOGL_ERROR, "GSM48 header does not fit.\n"); |
| return -1; |
| } |
| |
| msg->l4h = &msg->l3h[3]; |
| hdr48 = (struct gsm48_hdr *) msg->l4h; |
| |
| msg_type = hdr48->msg_type & 0xbf; |
| if (hdr48->proto_discr == GSM48_PDISC_MM && |
| msg_type == GSM48_MT_MM_ID_RESP) { |
| return _dt_check_id_resp(bsc, &hdr48->data[0], len - sizeof(*hdr48), con); |
| } else { |
| return 0; |
| } |
| } |
| |
| void bsc_parse_reg(void *ctx, regex_t *reg, char **imsi, int argc, const char **argv) |
| { |
| if (*imsi) { |
| talloc_free(*imsi); |
| *imsi = NULL; |
| } |
| regfree(reg); |
| |
| if (argc > 0) { |
| *imsi = talloc_strdup(ctx, argv[0]); |
| regcomp(reg, argv[0], 0); |
| } |
| } |
| |
| static const char *con_types [] = { |
| [NAT_CON_TYPE_NONE] = "n/a", |
| [NAT_CON_TYPE_LU] = "Location Update", |
| [NAT_CON_TYPE_CM_SERV_REQ] = "CM Serv Req", |
| [NAT_CON_TYPE_PAG_RESP] = "Paging Response", |
| [NAT_CON_TYPE_LOCAL_REJECT] = "Local Reject", |
| [NAT_CON_TYPE_OTHER] = "Other", |
| }; |
| |
| const char *bsc_con_type_to_string(int type) |
| { |
| return con_types[type]; |
| } |
| |
| struct bsc_nat_acc_lst *bsc_nat_acc_lst_find(struct bsc_nat *nat, const char *name) |
| { |
| struct bsc_nat_acc_lst *lst; |
| |
| if (!name) |
| return NULL; |
| |
| llist_for_each_entry(lst, &nat->access_lists, list) |
| if (strcmp(lst->name, name) == 0) |
| return lst; |
| |
| return NULL; |
| } |
| |
| struct bsc_nat_acc_lst *bsc_nat_acc_lst_get(struct bsc_nat *nat, const char *name) |
| { |
| struct bsc_nat_acc_lst *lst; |
| |
| lst = bsc_nat_acc_lst_find(nat, name); |
| if (lst) |
| return lst; |
| |
| lst = talloc_zero(nat, struct bsc_nat_acc_lst); |
| if (!lst) { |
| LOGP(DNAT, LOGL_ERROR, "Failed to allocate access list"); |
| return NULL; |
| } |
| |
| INIT_LLIST_HEAD(&lst->fltr_list); |
| lst->name = talloc_strdup(lst, name); |
| llist_add_tail(&lst->list, &nat->access_lists); |
| return lst; |
| } |
| |
| void bsc_nat_acc_lst_delete(struct bsc_nat_acc_lst *lst) |
| { |
| llist_del(&lst->list); |
| talloc_free(lst); |
| } |
| |
| struct bsc_nat_acc_lst_entry *bsc_nat_acc_lst_entry_create(struct bsc_nat_acc_lst *lst) |
| { |
| struct bsc_nat_acc_lst_entry *entry; |
| |
| entry = talloc_zero(lst, struct bsc_nat_acc_lst_entry); |
| if (!entry) |
| return NULL; |
| |
| llist_add_tail(&entry->list, &lst->fltr_list); |
| return entry; |
| } |
| |
| int bsc_nat_msc_is_connected(struct bsc_nat *nat) |
| { |
| return nat->msc_con->is_connected; |
| } |