diff options
Diffstat (limited to 'openbsc/src/nat')
| -rw-r--r-- | openbsc/src/nat/bsc_nat.c | 12 | ||||
| -rw-r--r-- | openbsc/src/nat/bsc_nat_utils.c | 154 | ||||
| -rw-r--r-- | openbsc/src/nat/bsc_nat_vty.c | 25 |
3 files changed, 190 insertions, 1 deletions
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c index a428e823d..3e878b87f 100644 --- a/openbsc/src/nat/bsc_nat.c +++ b/openbsc/src/nat/bsc_nat.c @@ -901,6 +901,15 @@ static int forward_sccp_to_msc(struct bsc_connection *bsc, struct msgb *msg) /* hand data to a side channel */ if (bsc_check_ussd(con, parsed, msg) == 1) con->con_local = 2; + + /* + * Optionally rewrite setup message. This can + * replace the msg and the parsed structure becomes + * invalid. + */ + msg = bsc_nat_rewrite_setup(bsc->nat, msg, parsed, con->imsi); + talloc_free(parsed); + parsed = NULL; } con_bsc = con->bsc; @@ -956,7 +965,8 @@ static int forward_sccp_to_msc(struct bsc_connection *bsc, struct msgb *msg) /* send the non-filtered but maybe modified msg */ queue_for_msc(con_msc, msg); - talloc_free(parsed); + if (parsed) + talloc_free(parsed); return 0; exit: diff --git a/openbsc/src/nat/bsc_nat_utils.c b/openbsc/src/nat/bsc_nat_utils.c index 0cef01b24..b345a77f5 100644 --- a/openbsc/src/nat/bsc_nat_utils.c +++ b/openbsc/src/nat/bsc_nat_utils.c @@ -721,3 +721,157 @@ int bsc_write_cb(struct bsc_fd *bfd, struct msgb *msg) 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; + } + + /* + * 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 */ + 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; +} + diff --git a/openbsc/src/nat/bsc_nat_vty.c b/openbsc/src/nat/bsc_nat_vty.c index 9eb8ebc75..af7e94c67 100644 --- a/openbsc/src/nat/bsc_nat_vty.c +++ b/openbsc/src/nat/bsc_nat_vty.c @@ -87,6 +87,9 @@ static int config_write_nat(struct vty *vty) if (_nat->ussd_local) vty_out(vty, " ussd-local-ip %s%s", _nat->ussd_local, VTY_NEWLINE); + if (_nat->num_rewr_name) + vty_out(vty, " number-rewrite %s%s", _nat->num_rewr_name, VTY_NEWLINE); + llist_for_each_entry(lst, &_nat->access_lists, list) { write_acc_lst(vty, lst); } @@ -403,6 +406,25 @@ DEFUN(cfg_nat_acc_lst_name, return CMD_SUCCESS; } +DEFUN(cfg_nat_number_rewrite, + cfg_nat_number_rewrite_cmd, + "number-rewrite FILENAME", + "Set the file with rewriting rules.\n" "Filename") +{ + bsc_replace_string(_nat, &_nat->num_rewr_name, argv[0]); + if (_nat->num_rewr_name) { + if (_nat->num_rewr) + talloc_free(_nat->num_rewr); + _nat->num_rewr = msg_entry_parse(_nat, _nat->num_rewr_name); + return _nat->num_rewr == NULL ? CMD_WARNING : CMD_SUCCESS; + } else { + if (_nat->num_rewr) + talloc_free(_nat->num_rewr); + _nat->num_rewr = NULL; + return CMD_SUCCESS; + } +} + DEFUN(cfg_nat_ussd_lst_name, cfg_nat_ussd_lst_name_cmd, "ussd-list-name NAME", @@ -688,6 +710,9 @@ int bsc_nat_vty_init(struct bsc_nat *nat) install_element(NAT_NODE, &cfg_lst_imsi_deny_cmd); install_element(NAT_NODE, &cfg_lst_no_cmd); + /* number rewriting */ + install_element(NAT_NODE, &cfg_nat_number_rewrite_cmd); + /* BSC subgroups */ install_element(NAT_NODE, &cfg_bsc_cmd); install_node(&bsc_node, config_write_bsc); |