From 03fd8d014f9871896a86534432c8757d65a576fe Mon Sep 17 00:00:00 2001 From: Jonathan Santos Date: Wed, 25 May 2011 13:54:02 -0400 Subject: Import upstream version 0.9.13 --- src/osmo-bsc_nat/bsc_nat_utils.c | 893 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 893 insertions(+) create mode 100644 src/osmo-bsc_nat/bsc_nat_utils.c (limited to 'src/osmo-bsc_nat/bsc_nat_utils.c') diff --git a/src/osmo-bsc_nat/bsc_nat_utils.c b/src/osmo-bsc_nat/bsc_nat_utils.c new file mode 100644 index 000000000..cd294ccfb --- /dev/null +++ b/src/osmo-bsc_nat/bsc_nat_utils.c @@ -0,0 +1,893 @@ + +/* BSC Multiplexer/NAT Utilities */ + +/* + * (C) 2010 by Holger Hans Peter Freyther + * (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 Affero General Public License as published by + * the Free Software Foundation; either version 3 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 Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see . + * + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +#include + +#include + +#include +#include +#include + +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. "}, + [BCFG_CTR_REJECTED_CR] = { "rejected.cr", "Rejected CR due filter "}, + [BCFG_CTR_REJECTED_MSG] = { "rejected.msg", "Rejected MSG due filter "}, + [BCFG_CTR_ILL_PACKET] = { "rejected.ill", "Rejected due parse error "}, + [BCFG_CTR_CON_TYPE_LU] = { "conn.lu", "Conn Location Update "}, + [BCFG_CTR_CON_CMSERV_RQ] = { "conn.rq", "Conn CM Service Req "}, + [BCFG_CTR_CON_PAG_RESP] = { "conn.pag", "Conn Paging Response "}, + [BCFG_CTR_CON_SSA] = { "conn.ssa", "Conn USSD "}, + [BCFG_CTR_CON_OTHER] = { "conn.other", "Conn Other "}, +}; + +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, +}; + +static const struct rate_ctr_desc acc_list_ctr_description[] = { + [ACC_LIST_BSC_FILTER] = { "access-list.bsc-filter", "Rejected by rule for BSC"}, + [ACC_LIST_NAT_FILTER] = { "access-list.nat-filter", "Rejected by rule for NAT"}, +}; + +static const struct rate_ctr_group_desc bsc_cfg_acc_list_desc = { + .group_name_prefix = "nat.filter", + .group_description = "NAT Access-List Statistics", + .num_ctr = ARRAY_SIZE(acc_list_ctr_description), + .ctr_desc = acc_list_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->stats.ussd.reconn = counter_alloc("nat.ussd.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) +{ + bsc_replace_string(nat, &nat->msc_ip, 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) +{ + struct bsc_config *conf = talloc_zero(nat, struct bsc_config); + if (!conf) + return NULL; + + conf->token = talloc_strdup(conf, token); + conf->nr = nat->num_bsc; + conf->nat = nat; + conf->max_endpoints = 32; + + INIT_LLIST_HEAD(&conf->lac_list); + + llist_add_tail(&conf->entry, &nat->bsc_configs); + ++nat->num_bsc; + + conf->stats.ctrg = rate_ctr_group_alloc(conf, &bsc_cfg_ctrg_desc, conf->nr); + if (!conf->stats.ctrg) { + talloc_free(conf); + return NULL; + } + + return conf; +} + +void bsc_config_free(struct bsc_config *cfg) +{ + rate_ctr_group_free(cfg->stats.ctrg); +} + +void bsc_config_add_lac(struct bsc_config *cfg, int _lac) +{ + struct bsc_lac_entry *lac; + + llist_for_each_entry(lac, &cfg->lac_list, entry) + if (lac->lac == _lac) + return; + + lac = talloc_zero(cfg, struct bsc_lac_entry); + if (!lac) { + LOGP(DNAT, LOGL_ERROR, "Failed to allocate.\n"); + return; + } + + lac->lac = _lac; + llist_add_tail(&lac->entry, &cfg->lac_list); +} + +void bsc_config_del_lac(struct bsc_config *cfg, int _lac) +{ + struct bsc_lac_entry *lac; + + llist_for_each_entry(lac, &cfg->lac_list, entry) + if (lac->lac == _lac) { + llist_del(&lac->entry); + talloc_free(lac); + return; + } +} + +int bsc_config_handles_lac(struct bsc_config *cfg, int lac_nr) +{ + struct bsc_lac_entry *entry; + + llist_for_each_entry(entry, &cfg->lac_list, entry) + if (entry->lac == lac_nr) + return 1; + + return 0; +} + +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) + continue; + if (!bsc_config_handles_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, IPAC_PROTO_MGCP_OLD); +} + +int bsc_write(struct bsc_connection *bsc, struct msgb *msg, int proto) +{ + return bsc_do_write(&bsc->write_queue, msg, proto); +} + +int bsc_do_write(struct write_queue *queue, struct msgb *msg, int proto) +{ + /* prepend the header */ + ipaccess_prepend_header(msg, proto); + return bsc_write_msg(queue, msg); +} + +int bsc_write_msg(struct write_queue *queue, struct msgb *msg) +{ + if (write_queue_enqueue(queue, msg) != 0) { + LOGP(DINP, LOGL_ERROR, "Failed to enqueue the write.\n"); + msgb_free(msg); + return -1; + } + + return 0; +} + +int bsc_nat_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.) Allow directly if the IMSI is allowed at the BSC + * 2.) Reject if the IMSI is not 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 allow */ + if (bsc_nat_lst_check_allow(bsc_lst, mi_string) == 0) + return 1; + + /* 2. 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); + rate_ctr_inc(&bsc_lst->stats->ctr[ACC_LIST_BSC_FILTER]); + return -2; + } + + } + + /* 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); + rate_ctr_inc(&nat_lst->stats->ctr[ACC_LIST_NAT_FILTER]); + return -3; + } + } + + return 1; +} + +static int _cr_check_loc_upd(struct bsc_connection *bsc, + uint8_t *data, unsigned int length, + char **imsi) +{ + 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); + *imsi = talloc_strdup(bsc, mi_string); + return auth_imsi(bsc, mi_string); +} + +static int _cr_check_cm_serv_req(struct bsc_connection *bsc, + uint8_t *data, unsigned int length, + int *con_type, char **imsi) +{ + 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; + if (req->cm_service_type == 0x8) + *con_type = NAT_CON_TYPE_SSA; + 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; + + *imsi = talloc_strdup(bsc, mi_string); + return auth_imsi(bsc, mi_string); +} + +static int _cr_check_pag_resp(struct bsc_connection *bsc, + uint8_t *data, unsigned int length, + char **imsi) +{ + 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; + + *imsi = talloc_strdup(bsc, mi_string); + 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; + con->imsi = talloc_strdup(con, mi_string); + 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, + char **imsi) +{ + struct tlv_parsed tp; + struct gsm48_hdr *hdr48; + int hdr48_len; + int len; + uint8_t msg_type; + + *con_type = NAT_CON_TYPE_NONE; + *imsi = NULL; + + 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), imsi); + } 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), + con_type, imsi); + } 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), imsi); + } else { + /* We only want to filter the above, let other things pass */ + *con_type = NAT_CON_TYPE_OTHER; + return 0; + } +} + +struct gsm48_hdr *bsc_unpack_dtap(struct bsc_nat_parsed *parsed, + struct msgb *msg, uint32_t *len) +{ + /* 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 NULL; + } + + if (*len < sizeof(struct gsm48_hdr)) { + LOGP(DNAT, LOGL_ERROR, "GSM48 header does not fit.\n"); + return NULL; + } + + msg->l4h = &msg->l3h[3]; + return (struct gsm48_hdr *) msg->l4h; +} + +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; + + hdr48 = bsc_unpack_dtap(parsed, msg, &len); + if (!hdr48) + return -1; + + 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_SSA] = "Supplementar Service Activation", + [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; + } + + /* TODO: get the index right */ + lst->stats = rate_ctr_group_alloc(lst, &bsc_cfg_acc_list_desc, 0); + if (!lst->stats) { + talloc_free(lst); + 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); + rate_ctr_group_free(lst->stats); + 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; +} + +static const int con_to_ctr[] = { + [NAT_CON_TYPE_NONE] = -1, + [NAT_CON_TYPE_LU] = BCFG_CTR_CON_TYPE_LU, + [NAT_CON_TYPE_CM_SERV_REQ] = BCFG_CTR_CON_CMSERV_RQ, + [NAT_CON_TYPE_PAG_RESP] = BCFG_CTR_CON_PAG_RESP, + [NAT_CON_TYPE_SSA] = BCFG_CTR_CON_SSA, + [NAT_CON_TYPE_LOCAL_REJECT] = -1, + [NAT_CON_TYPE_OTHER] = BCFG_CTR_CON_OTHER, +}; + +int bsc_conn_type_to_ctr(struct sccp_connections *conn) +{ + return con_to_ctr[conn->con_type]; +} + +int bsc_write_cb(struct bsc_fd *bfd, struct msgb *msg) +{ + int rc; + + rc = write(bfd->fd, msg->data, msg->len); + if (rc != msg->len) + LOGP(DNAT, LOGL_ERROR, "Failed to write message to the BSC.\n"); + + return rc; +} + +/** + * Rewrite non global numbers... according to rules based on the IMSI + */ +struct msgb *bsc_nat_rewrite_setup(struct bsc_nat *nat, struct msgb *msg, struct bsc_nat_parsed *parsed, const char *imsi) +{ + struct tlv_parsed tp; + struct gsm48_hdr *hdr48; + uint32_t len; + uint8_t msg_type; + unsigned int payload_len; + struct gsm_mncc_number called; + struct msg_entry *entry; + char *new_number = NULL; + struct msgb *out, *sccp; + uint8_t *outptr; + const uint8_t *msgptr; + int sec_len; + + if (!imsi || strlen(imsi) < 5) + return msg; + + if (!nat->num_rewr) + return msg; + + /* only care about DTAP messages */ + if (parsed->bssap != BSSAP_MSG_DTAP) + return msg; + if (!parsed->dest_local_ref) + return msg; + + hdr48 = bsc_unpack_dtap(parsed, msg, &len); + if (!hdr48) + return msg; + + msg_type = hdr48->msg_type & 0xbf; + if (hdr48->proto_discr != GSM48_PDISC_CC || + msg_type != GSM48_MT_CC_SETUP) + return msg; + + /* decode and rewrite the message */ + payload_len = len - sizeof(*hdr48); + tlv_parse(&tp, &gsm48_att_tlvdef, hdr48->data, payload_len, 0, 0); + + /* no number, well let us ignore it */ + if (!TLVP_PRESENT(&tp, GSM48_IE_CALLED_BCD)) + return msg; + + memset(&called, 0, sizeof(called)); + gsm48_decode_called(&called, + TLVP_VAL(&tp, GSM48_IE_CALLED_BCD) - 1); + + /* check if it looks international and stop */ + if (called.plan != 1) + return msg; + if (called.type == 1) + return msg; + if (strncmp(called.number, "00", 2) == 0) + return msg; + + /* need to find a replacement and then fix it */ + llist_for_each_entry(entry, &nat->num_rewr->entry, list) { + regex_t reg; + regmatch_t matches[2]; + + if (entry->mcc[0] != '*' && strncmp(entry->mcc, imsi, 3) != 0) + continue; + if (entry->mnc[0] != '*' && strncmp(entry->mnc, imsi + 3, 2) != 0) + continue; + + if (entry->text[0] == '+') { + LOGP(DNAT, LOGL_ERROR, + "Plus is not allowed in the number"); + continue; + } + + /* We have an entry for the IMSI. Need to match now */ + if (regcomp(®, entry->option, REG_EXTENDED) != 0) { + LOGP(DNAT, LOGL_ERROR, + "Regexp '%s' is not valid.\n", entry->option); + continue; + } + + /* this regexp matches... */ + if (regexec(®, called.number, 2, matches, 0) == 0 && + matches[1].rm_eo != -1) + new_number = talloc_asprintf(msg, "%s%s", + entry->text, + &called.number[matches[1].rm_so]); + regfree(®); + + if (new_number) + break; + } + + if (!new_number) { + LOGP(DNAT, LOGL_DEBUG, "No IMSI match found, returning message.\n"); + return msg; + } + + if (strlen(new_number) > sizeof(called.number)) { + LOGP(DNAT, LOGL_ERROR, "Number is too long for structure.\n"); + talloc_free(new_number); + return msg; + } + + /* + * Need to create a new message now based on the old onew + * with a new number. We can sadly not patch this in place + * so we will need to regenerate it. + */ + + out = msgb_alloc_headroom(4096, 128, "changed-setup"); + if (!out) { + LOGP(DNAT, LOGL_ERROR, "Failed to allocate.\n"); + talloc_free(new_number); + return msg; + } + + /* copy the header */ + outptr = msgb_put(out, sizeof(*hdr48)); + memcpy(outptr, hdr48, sizeof(*hdr48)); + + /* copy everything up to the number */ + sec_len = TLVP_VAL(&tp, GSM48_IE_CALLED_BCD) - 2 - &hdr48->data[0]; + outptr = msgb_put(out, sec_len); + memcpy(outptr, &hdr48->data[0], sec_len); + + /* create the new number */ + if (strncmp(new_number, "00", 2) == 0) { + called.type = 1; + strncpy(called.number, new_number + 2, sizeof(called.number)); + } else { + strncpy(called.number, new_number, sizeof(called.number)); + } + gsm48_encode_called(out, &called); + + /* copy thre rest */ + msgptr = TLVP_VAL(&tp, GSM48_IE_CALLED_BCD) + + TLVP_LEN(&tp, GSM48_IE_CALLED_BCD); + sec_len = payload_len - (msgptr - &hdr48->data[0]); + outptr = msgb_put(out, sec_len); + memcpy(outptr, msgptr, sec_len); + + /* wrap with DTAP, SCCP, then IPA. TODO: Stop copying */ + gsm0808_prepend_dtap_header(out, 0); + sccp = sccp_create_dt1(parsed->dest_local_ref, out->data, out->len); + if (!sccp) { + LOGP(DNAT, LOGL_ERROR, "Failed to allocate.\n"); + talloc_free(new_number); + talloc_free(out); + return msg; + } + + ipaccess_prepend_header(sccp, IPAC_PROTO_SCCP); + + /* give up memory, we are done */ + talloc_free(new_number); + /* the parsed hangs off from msg but it needs to survive */ + talloc_steal(sccp, parsed); + msgb_free(msg); + msgb_free(out); + out = NULL; + return sccp; +} + -- cgit v1.2.3