diff options
Diffstat (limited to 'src/osmo-bsc_nat/bsc_nat_rewrite.c')
| -rw-r--r-- | src/osmo-bsc_nat/bsc_nat_rewrite.c | 714 |
1 files changed, 0 insertions, 714 deletions
diff --git a/src/osmo-bsc_nat/bsc_nat_rewrite.c b/src/osmo-bsc_nat/bsc_nat_rewrite.c deleted file mode 100644 index e7c387c22..000000000 --- a/src/osmo-bsc_nat/bsc_nat_rewrite.c +++ /dev/null @@ -1,714 +0,0 @@ -/* - * Message rewriting functionality - */ -/* - * (C) 2010-2013 by Holger Hans Peter Freyther <zecke@selfish.org> - * (C) 2010-2013 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 <http://www.gnu.org/licenses/>. - * - */ - -#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 <openbsc/nat_rewrite_trie.h> - -#include <osmocom/core/linuxlist.h> -#include <osmocom/core/talloc.h> -#include <osmocom/core/utils.h> -#include <osmocom/gsm/gsm0808.h> -#include <osmocom/gsm/ipa.h> - -#include <osmocom/gsm/protocol/gsm_08_08.h> -#include <osmocom/gsm/protocol/gsm_04_11.h> - -#include <osmocom/sccp/sccp.h> - -static char *trie_lookup(struct nat_rewrite *trie, const char *number, - regoff_t off, void *ctx) -{ - struct nat_rewrite_rule *rule; - - if (!trie) { - LOGP(DCC, LOGL_ERROR, - "Asked to do a table lookup but no table.\n"); - return NULL; - } - - rule = nat_rewrite_lookup(trie, number); - if (!rule) { - LOGP(DCC, LOGL_DEBUG, - "Couldn't find a prefix rule for %s\n", number); - return NULL; - } - - return talloc_asprintf(ctx, "%s%s", rule->rewrite, &number[off]); -} - -static char *match_and_rewrite_number(void *ctx, const char *number, - const char *imsi, struct llist_head *list, - struct nat_rewrite *trie) -{ - struct bsc_nat_num_rewr_entry *entry; - char *new_number = NULL; - - /* need to find a replacement and then fix it */ - llist_for_each_entry(entry, list, list) { - regmatch_t matches[2]; - - /* check the IMSI match */ - if (regexec(&entry->msisdn_reg, imsi, 0, NULL, 0) != 0) - continue; - - /* this regexp matches... */ - if (regexec(&entry->num_reg, number, 2, matches, 0) == 0 - && matches[1].rm_eo != -1) { - if (entry->is_prefix_lookup) - new_number = trie_lookup(trie, number, - matches[1].rm_so, ctx); - else - new_number = talloc_asprintf(ctx, "%s%s", - entry->replace, - &number[matches[1].rm_so]); - } - - if (new_number) - break; - } - - return new_number; -} - -static char *rewrite_isdn_number(struct bsc_nat *nat, struct llist_head *rewr_list, - void *ctx, const char *imsi, - struct gsm_mncc_number *called) -{ - char int_number[sizeof(called->number) + 2]; - char *number = called->number; - - if (llist_empty(&nat->num_rewr)) { - LOGP(DCC, LOGL_DEBUG, "Rewrite rules empty.\n"); - return NULL; - } - - /* only ISDN plan */ - if (called->plan != 1) { - LOGP(DCC, LOGL_DEBUG, "Called plan is not 1 it was %d\n", - called->plan); - return NULL; - } - - /* international, prepend */ - if (called->type == 1) { - int_number[0] = '+'; - memcpy(&int_number[1], number, strlen(number) + 1); - number = int_number; - } - - return match_and_rewrite_number(ctx, number, - imsi, rewr_list, nat->num_rewr_trie); -} - -static void update_called_number(struct gsm_mncc_number *called, - const char *chosen_number) -{ - if (strncmp(chosen_number, "00", 2) == 0) { - called->type = 1; - osmo_strlcpy(called->number, chosen_number + 2, - sizeof(called->number)); - } else { - /* rewrite international to unknown */ - if (called->type == 1) - called->type = 0; - osmo_strlcpy(called->number, chosen_number, - sizeof(called->number)); - } -} - -/** - * Rewrite non global numbers... according to rules based on the IMSI - */ -static struct msgb *rewrite_setup(struct bsc_nat *nat, struct msgb *msg, - struct bsc_nat_parsed *parsed, const char *imsi, - struct gsm48_hdr *hdr48, const uint32_t len) -{ - struct tlv_parsed tp; - unsigned int payload_len; - struct gsm_mncc_number called; - struct msgb *out; - char *new_number_pre = NULL, *new_number_post = NULL, *chosen_number; - uint8_t *outptr; - const uint8_t *msgptr; - int sec_len; - - /* 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 NULL; - - memset(&called, 0, sizeof(called)); - gsm48_decode_called(&called, - TLVP_VAL(&tp, GSM48_IE_CALLED_BCD) - 1); - - /* check if it looks international and stop */ - LOGP(DCC, LOGL_DEBUG, - "Pre-Rewrite for IMSI(%s) Plan(%d) Type(%d) Number(%s)\n", - imsi, called.plan, called.type, called.number); - new_number_pre = rewrite_isdn_number(nat, &nat->num_rewr, msg, imsi, &called); - - if (!new_number_pre) { - LOGP(DCC, LOGL_DEBUG, "No IMSI(%s) match found, returning message.\n", - imsi); - return NULL; - } - - if (strlen(new_number_pre) > sizeof(called.number)) { - LOGP(DCC, LOGL_ERROR, "Number %s is too long for structure.\n", - new_number_pre); - talloc_free(new_number_pre); - return NULL; - } - update_called_number(&called, new_number_pre); - - /* another run through the re-write engine with other rules */ - LOGP(DCC, LOGL_DEBUG, - "Post-Rewrite for IMSI(%s) Plan(%d) Type(%d) Number(%s)\n", - imsi, called.plan, called.type, called.number); - new_number_post = rewrite_isdn_number(nat, &nat->num_rewr_post, msg, - imsi, &called); - chosen_number = new_number_post ? new_number_post : new_number_pre; - - - if (strlen(chosen_number) > sizeof(called.number)) { - LOGP(DCC, LOGL_ERROR, "Number %s is too long for structure.\n", - chosen_number); - talloc_free(new_number_pre); - talloc_free(new_number_post); - return NULL; - } - - /* - * 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(DCC, LOGL_ERROR, "Failed to allocate.\n"); - talloc_free(new_number_pre); - talloc_free(new_number_post); - return NULL; - } - - /* 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 */ - update_called_number(&called, chosen_number); - LOGP(DCC, LOGL_DEBUG, - "Chosen number for IMSI(%s) is Plan(%d) Type(%d) Number(%s)\n", - imsi, called.plan, called.type, 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); - - talloc_free(new_number_pre); - talloc_free(new_number_post); - return out; -} - -/** - * Find a new SMSC address, returns an allocated string that needs to be - * freed or is NULL. - */ -static char *find_new_smsc(struct bsc_nat *nat, void *ctx, const char *imsi, - const char *smsc_addr, const char *dest_nr) -{ - struct bsc_nat_num_rewr_entry *entry; - char *new_number = NULL; - uint8_t dest_match = llist_empty(&nat->tpdest_match); - - /* We will find a new number now */ - llist_for_each_entry(entry, &nat->smsc_rewr, list) { - regmatch_t matches[2]; - - /* check the IMSI match */ - if (regexec(&entry->msisdn_reg, imsi, 0, NULL, 0) != 0) - continue; - - /* this regexp matches... */ - if (regexec(&entry->num_reg, smsc_addr, 2, matches, 0) == 0 && - matches[1].rm_eo != -1) - new_number = talloc_asprintf(ctx, "%s%s", - entry->replace, - &smsc_addr[matches[1].rm_so]); - if (new_number) - break; - } - - if (!new_number) - return NULL; - - /* - * now match the number against another list - */ - llist_for_each_entry(entry, &nat->tpdest_match, list) { - /* check the IMSI match */ - if (regexec(&entry->msisdn_reg, imsi, 0, NULL, 0) != 0) - continue; - - if (regexec(&entry->num_reg, dest_nr, 0, NULL, 0) == 0) { - dest_match = 1; - break; - } - } - - if (!dest_match) { - talloc_free(new_number); - return NULL; - } - - return new_number; -} - -/** - * Clear the TP-SRR from the TPDU header - */ -static uint8_t sms_new_tpdu_hdr(struct bsc_nat *nat, const char *imsi, - const char *dest_nr, uint8_t hdr) -{ - struct bsc_nat_num_rewr_entry *entry; - - /* We will find a new number now */ - llist_for_each_entry(entry, &nat->sms_clear_tp_srr, list) { - /* check the IMSI match */ - if (regexec(&entry->msisdn_reg, imsi, 0, NULL, 0) != 0) - continue; - if (regexec(&entry->num_reg, dest_nr, 0, NULL, 0) != 0) - continue; - - /* matched phone number and imsi */ - return hdr & ~0x20; - } - - return hdr; -} - -/** - * Check if we need to rewrite the number. For this SMS. - */ -static char *sms_new_dest_nr(struct bsc_nat *nat, void *ctx, - const char *imsi, const char *dest_nr) -{ - return match_and_rewrite_number(ctx, dest_nr, imsi, - &nat->sms_num_rewr, NULL); -} - -/** - * This is a helper for GSM 04.11 8.2.5.2 Destination address element - */ -void sms_encode_addr_element(struct msgb *out, const char *new_number, - int format, int tp_data) -{ - uint8_t new_addr_len; - uint8_t new_addr[26]; - - /* - * Copy the new number. We let libosmocore encode it, then set - * the extension followed after the length. Depending on if - * we want to write RP we will let the TLV code add the - * length for us or we need to use strlen... This is not very clear - * as of 03.40 and 04.11. - */ - new_addr_len = gsm48_encode_bcd_number(new_addr, ARRAY_SIZE(new_addr), - 1, new_number); - new_addr[1] = format; - if (tp_data) { - uint8_t *data = msgb_put(out, new_addr_len); - memcpy(data, new_addr, new_addr_len); - data[0] = strlen(new_number); - } else { - msgb_lv_put(out, new_addr_len - 1, new_addr + 1); - } -} - -static struct msgb *sms_create_new(uint8_t type, uint8_t ref, - struct gsm48_hdr *old_hdr48, - const uint8_t *orig_addr_ptr, - int orig_addr_len, const char *new_number, - const uint8_t *data_ptr, int data_len, - uint8_t tpdu_first_byte, - const int old_dest_len, const char *new_dest_nr) -{ - struct gsm48_hdr *new_hdr48; - struct msgb *out; - - /* - * We need to re-create the patched structure. This is why we have - * saved the above pointers. - */ - out = msgb_alloc_headroom(4096, 128, "changed-smsc"); - if (!out) { - LOGP(DNAT, LOGL_ERROR, "Failed to allocate.\n"); - return NULL; - } - - out->l2h = out->data; - msgb_v_put(out, GSM411_MT_RP_DATA_MO); - msgb_v_put(out, ref); - msgb_lv_put(out, orig_addr_len, orig_addr_ptr); - - sms_encode_addr_element(out, new_number, 0x91, 0); - - - /* Patch the TPDU from here on */ - - /** - * Do we need to put a new TP-Destination-Address (TP-DA) here or - * can we copy the old thing? For the TP-DA we need to find out the - * new size. - */ - if (new_dest_nr) { - uint8_t *data, *new_size; - - /* reserve the size and write the header */ - new_size = msgb_put(out, 1); - out->l3h = new_size + 1; - msgb_v_put(out, tpdu_first_byte); - msgb_v_put(out, data_ptr[1]); - - /* encode the new number and put it */ - if (strncmp(new_dest_nr, "00", 2) == 0) - sms_encode_addr_element(out, new_dest_nr + 2, 0x91, 1); - else - sms_encode_addr_element(out, new_dest_nr, 0x81, 1); - - /* Copy the rest after the TP-DS */ - data = msgb_put(out, data_len - 2 - 1 - old_dest_len); - memcpy(data, &data_ptr[2 + 1 + old_dest_len], data_len - 2 - 1 - old_dest_len); - - /* fill in the new size */ - new_size[0] = msgb_l3len(out); - } else { - msgb_v_put(out, data_len); - msgb_tv_fixed_put(out, tpdu_first_byte, data_len - 1, &data_ptr[1]); - } - - /* prepend GSM 04.08 header */ - new_hdr48 = (struct gsm48_hdr *) msgb_push(out, sizeof(*new_hdr48) + 1); - memcpy(new_hdr48, old_hdr48, sizeof(*old_hdr48)); - new_hdr48->data[0] = msgb_l2len(out); - - return out; -} - -/** - * Parse the SMS and check if it needs to be rewritten - */ -static struct msgb *rewrite_sms(struct bsc_nat *nat, struct msgb *msg, - struct bsc_nat_parsed *parsed, const char *imsi, - struct gsm48_hdr *hdr48, const uint32_t len) -{ - unsigned int payload_len; - unsigned int cp_len; - - uint8_t ref; - uint8_t orig_addr_len, *orig_addr_ptr; - uint8_t dest_addr_len, *dest_addr_ptr; - uint8_t data_len, *data_ptr; - char smsc_addr[30]; - - - uint8_t dest_len, orig_dest_len; - char _dest_nr[30]; - char *dest_nr; - char *new_dest_nr; - - char *new_number = NULL; - uint8_t tpdu_hdr; - struct msgb *out; - - payload_len = len - sizeof(*hdr48); - if (payload_len < 1) { - LOGP(DNAT, LOGL_ERROR, "SMS too short for things. %d\n", payload_len); - return NULL; - } - - cp_len = hdr48->data[0]; - if (payload_len + 1 < cp_len) { - LOGP(DNAT, LOGL_ERROR, "SMS RPDU can not fit in: %d %d\n", cp_len, payload_len); - return NULL; - } - - if (hdr48->data[1] != GSM411_MT_RP_DATA_MO) - return NULL; - - if (cp_len < 5) { - LOGP(DNAT, LOGL_ERROR, "RD-DATA can not fit in the CP len: %d\n", cp_len); - return NULL; - } - - /* RP */ - ref = hdr48->data[2]; - orig_addr_len = hdr48->data[3]; - orig_addr_ptr = &hdr48->data[4]; - - /* the +1 is for checking if the following element has some space */ - if (cp_len < 3 + orig_addr_len + 1) { - LOGP(DNAT, LOGL_ERROR, "RP-Originator addr does not fit: %d\n", orig_addr_len); - return NULL; - } - - dest_addr_len = hdr48->data[3 + orig_addr_len + 1]; - dest_addr_ptr = &hdr48->data[3 + orig_addr_len + 2]; - - if (cp_len < 3 + orig_addr_len + 1 + dest_addr_len + 1) { - LOGP(DNAT, LOGL_ERROR, "RP-Destination addr does not fit: %d\n", dest_addr_len); - return NULL; - } - gsm48_decode_bcd_number(smsc_addr, ARRAY_SIZE(smsc_addr), dest_addr_ptr - 1, 1); - - data_len = hdr48->data[3 + orig_addr_len + 1 + dest_addr_len + 1]; - data_ptr = &hdr48->data[3 + orig_addr_len + 1 + dest_addr_len + 2]; - - if (cp_len < 3 + orig_addr_len + 1 + dest_addr_len + 1 + data_len) { - LOGP(DNAT, LOGL_ERROR, "RP-Data does not fit: %d\n", data_len); - return NULL; - } - - if (data_len < 3) { - LOGP(DNAT, LOGL_ERROR, "SMS-SUBMIT is too short.\n"); - return NULL; - } - - /* TP-PDU starts here */ - if ((data_ptr[0] & 0x03) != GSM340_SMS_SUBMIT_MS2SC) - return NULL; - - /* - * look into the phone number. The length is in semi-octets, we will - * need to add the byte for the number type as well. - */ - orig_dest_len = data_ptr[2]; - dest_len = ((orig_dest_len + 1) / 2) + 1; - if (data_len < dest_len + 3 || dest_len < 2) { - LOGP(DNAT, LOGL_ERROR, "SMS-SUBMIT can not have TP-DestAddr.\n"); - return NULL; - } - - if ((data_ptr[3] & 0x80) == 0) { - LOGP(DNAT, LOGL_ERROR, "TP-DestAddr has extension. Not handled.\n"); - return NULL; - } - - if ((data_ptr[3] & 0x0F) == 0) { - LOGP(DNAT, LOGL_ERROR, "TP-DestAddr is of unknown type.\n"); - return NULL; - } - - /** - * Besides of what I think I read in GSM 03.40 and 04.11 the TP-DA - * contains the semi-octets as length (strlen), change it to the - * the number of bytes, but then change it back. - */ - data_ptr[2] = dest_len; - gsm48_decode_bcd_number(_dest_nr + 2, ARRAY_SIZE(_dest_nr) - 2, - &data_ptr[2], 1); - data_ptr[2] = orig_dest_len; - if ((data_ptr[3] & 0x70) == 0x10) { - _dest_nr[0] = _dest_nr[1] = '0'; - dest_nr = &_dest_nr[0]; - } else { - dest_nr = &_dest_nr[2]; - } - - /** - * Call functions to rewrite the data - */ - tpdu_hdr = sms_new_tpdu_hdr(nat, imsi, dest_nr, data_ptr[0]); - new_number = find_new_smsc(nat, msg, imsi, smsc_addr, dest_nr); - new_dest_nr = sms_new_dest_nr(nat, msg, imsi, dest_nr); - - if (tpdu_hdr == data_ptr[0] && !new_number && !new_dest_nr) - return NULL; - - out = sms_create_new(GSM411_MT_RP_DATA_MO, ref, hdr48, - orig_addr_ptr, orig_addr_len, - new_number ? new_number : smsc_addr, - data_ptr, data_len, tpdu_hdr, - dest_len, new_dest_nr); - talloc_free(new_number); - talloc_free(new_dest_nr); - return out; -} - -struct msgb *bsc_nat_rewrite_msg(struct bsc_nat *nat, struct msgb *msg, struct bsc_nat_parsed *parsed, const char *imsi) -{ - struct gsm48_hdr *hdr48; - uint32_t len; - uint8_t msg_type, proto; - struct msgb *new_msg = NULL, *sccp; - uint8_t link_id; - - if (!imsi || strlen(imsi) < 5) - 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; - - link_id = msg->l3h[1]; - proto = gsm48_hdr_pdisc(hdr48); - msg_type = gsm48_hdr_msg_type(hdr48); - - if (proto == GSM48_PDISC_CC && msg_type == GSM48_MT_CC_SETUP) - new_msg = rewrite_setup(nat, msg, parsed, imsi, hdr48, len); - else if (proto == GSM48_PDISC_SMS && msg_type == GSM411_MT_CP_DATA) - new_msg = rewrite_sms(nat, msg, parsed, imsi, hdr48, len); - - if (!new_msg) - return msg; - - /* wrap with DTAP, SCCP, then IPA. TODO: Stop copying */ - gsm0808_prepend_dtap_header(new_msg, link_id); - sccp = sccp_create_dt1(parsed->dest_local_ref, new_msg->data, new_msg->len); - talloc_free(new_msg); - - if (!sccp) { - LOGP(DNAT, LOGL_ERROR, "Failed to allocate.\n"); - return msg; - } - - ipa_prepend_header(sccp, IPAC_PROTO_SCCP); - - /* the parsed hangs off from msg but it needs to survive */ - talloc_steal(sccp, parsed); - msgb_free(msg); - return sccp; -} - -static void num_rewr_free_data(struct bsc_nat_num_rewr_entry *entry) -{ - regfree(&entry->msisdn_reg); - regfree(&entry->num_reg); - talloc_free(entry->replace); -} - -void bsc_nat_num_rewr_entry_adapt(void *ctx, struct llist_head *head, - const struct osmo_config_list *list) -{ - struct bsc_nat_num_rewr_entry *entry, *tmp; - struct osmo_config_entry *cfg_entry; - - /* free the old data */ - llist_for_each_entry_safe(entry, tmp, head, list) { - num_rewr_free_data(entry); - llist_del(&entry->list); - talloc_free(entry); - } - - - if (!list) - return; - - llist_for_each_entry(cfg_entry, &list->entry, list) { - char *regexp; - if (cfg_entry->text[0] == '+') { - LOGP(DNAT, LOGL_ERROR, - "Plus is not allowed in the number\n"); - continue; - } - - entry = talloc_zero(ctx, struct bsc_nat_num_rewr_entry); - if (!entry) { - LOGP(DNAT, LOGL_ERROR, - "Allocation of the num_rewr entry failed.\n"); - continue; - } - - entry->replace = talloc_strdup(entry, cfg_entry->text); - if (!entry->replace) { - LOGP(DNAT, LOGL_ERROR, - "Failed to copy the replacement text.\n"); - talloc_free(entry); - continue; - } - - if (strcmp("prefix_lookup", entry->replace) == 0) - entry->is_prefix_lookup = 1; - - /* we will now build a regexp string */ - if (cfg_entry->mcc[0] == '^') { - regexp = talloc_strdup(entry, cfg_entry->mcc); - } else { - regexp = talloc_asprintf(entry, "^%s%s", - cfg_entry->mcc[0] == '*' ? - "[0-9][0-9][0-9]" : cfg_entry->mcc, - cfg_entry->mnc[0] == '*' ? - "[0-9][0-9]" : cfg_entry->mnc); - } - - if (!regexp) { - LOGP(DNAT, LOGL_ERROR, "Failed to create a regexp string.\n"); - talloc_free(entry); - continue; - } - - if (regcomp(&entry->msisdn_reg, regexp, 0) != 0) { - LOGP(DNAT, LOGL_ERROR, - "Failed to compile regexp '%s'\n", regexp); - talloc_free(regexp); - talloc_free(entry); - continue; - } - - talloc_free(regexp); - if (regcomp(&entry->num_reg, cfg_entry->option, REG_EXTENDED) != 0) { - LOGP(DNAT, LOGL_ERROR, - "Failed to compile regexp '%s'\n", cfg_entry->option); - regfree(&entry->msisdn_reg); - talloc_free(entry); - continue; - } - - /* we have copied the number */ - llist_add_tail(&entry->list, head); - } -} |