nat: Patch the destination SMS address of a message
Use the same filtering infrasturcture to patch the SMSC address in a CP-DATA/RP-DATA message. Add a very simple testcase for this code.
This commit is contained in:
Holger Hans Peter Freyther
parent
2e2ff34021
commit
9c20571280
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@ -269,6 +269,9 @@ struct bsc_nat {
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char *num_rewr_name;
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struct llist_head num_rewr;
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char *smsc_rewr_name;
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struct llist_head smsc_rewr;
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/* USSD messages we want to match */
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char *ussd_lst_name;
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char *ussd_query;
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@ -406,6 +409,6 @@ struct bsc_nat_num_rewr_entry {
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char *replace;
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};
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void bsc_nat_num_rewr_entry_adapt(struct bsc_nat *nat, const struct osmo_config_list *);
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void bsc_nat_num_rewr_entry_adapt(void *ctx, struct llist_head *head, const struct osmo_config_list *);
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#endif
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@ -34,6 +34,7 @@
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#include <osmocom/gsm/gsm0808.h>
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#include <osmocom/gsm/protocol/gsm_08_08.h>
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#include <osmocom/gsm/protocol/gsm_04_11.h>
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#include <osmocom/sccp/sccp.h>
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@ -95,6 +96,7 @@ struct bsc_nat *bsc_nat_alloc(void)
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INIT_LLIST_HEAD(&nat->access_lists);
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INIT_LLIST_HEAD(&nat->dests);
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INIT_LLIST_HEAD(&nat->num_rewr);
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INIT_LLIST_HEAD(&nat->smsc_rewr);
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nat->stats.sccp.conn = osmo_counter_alloc("nat.sccp.conn");
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nat->stats.sccp.calls = osmo_counter_alloc("nat.sccp.calls");
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@ -919,6 +921,130 @@ static struct msgb *rewrite_setup(struct bsc_nat *nat, struct msgb *msg,
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return out;
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}
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static struct msgb *rewrite_smsc(struct bsc_nat *nat, struct msgb *msg,
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struct bsc_nat_parsed *parsed, const char *imsi,
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struct gsm48_hdr *hdr48, const uint32_t len)
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{
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unsigned int payload_len;
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unsigned int cp_len;
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uint8_t ref;
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uint8_t orig_addr_len, *orig_addr_ptr;
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uint8_t dest_addr_len, *dest_addr_ptr;
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uint8_t data_len, *data_ptr;
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char smsc_addr[30];
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uint8_t new_addr[12];
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struct bsc_nat_num_rewr_entry *entry;
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char *new_number = NULL;
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uint8_t new_addr_len;
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struct gsm48_hdr *new_hdr48;
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struct msgb *out;
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payload_len = len - sizeof(*hdr48);
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if (payload_len < 1) {
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LOGP(DNAT, LOGL_ERROR, "SMS too short for things. %d\n", payload_len);
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return NULL;
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}
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cp_len = hdr48->data[0];
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if (payload_len + 1 < cp_len) {
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LOGP(DNAT, LOGL_ERROR, "SMS RPDU can not fit in: %d %d\n", cp_len, payload_len);
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return NULL;
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}
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if (hdr48->data[1] != GSM411_MT_RP_DATA_MO)
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return NULL;
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if (cp_len < 5) {
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LOGP(DNAT, LOGL_ERROR, "RD-DATA can not fit in the CP len: %d\n", cp_len);
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return NULL;
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}
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ref = hdr48->data[2];
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orig_addr_len = hdr48->data[3];
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orig_addr_ptr = &hdr48->data[4];
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/* the +1 is for checking if the following element has some space */
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if (cp_len < 3 + orig_addr_len + 1) {
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LOGP(DNAT, LOGL_ERROR, "RP-Originator addr does not fit: %d\n", orig_addr_len);
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return NULL;
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}
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dest_addr_len = hdr48->data[3 + orig_addr_len + 1];
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dest_addr_ptr = &hdr48->data[3 + orig_addr_len + 2];
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if (cp_len < 3 + orig_addr_len + 1 + dest_addr_len + 1) {
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LOGP(DNAT, LOGL_ERROR, "RP-Destination addr does not fit: %d\n", dest_addr_len);
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return NULL;
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}
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gsm48_decode_bcd_number(smsc_addr, ARRAY_SIZE(smsc_addr), dest_addr_ptr - 1, 1);
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data_len = hdr48->data[3 + orig_addr_len + 1 + dest_addr_len + 1];
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data_ptr = &hdr48->data[3 + orig_addr_len + 1 + dest_addr_len + 2];
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if (cp_len < 3 + orig_addr_len + 1 + dest_addr_len + 1 + data_len) {
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LOGP(DNAT, LOGL_ERROR, "RP-Data does not fit: %d\n", data_len);
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return NULL;
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}
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/* We will find a new number now */
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llist_for_each_entry(entry, &nat->smsc_rewr, list) {
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regmatch_t matches[2];
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/* check the IMSI match */
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if (regexec(&entry->msisdn_reg, imsi, 0, NULL, 0) != 0)
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continue;
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/* this regexp matches... */
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if (regexec(&entry->num_reg, smsc_addr, 2, matches, 0) == 0 &&
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matches[1].rm_eo != -1)
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new_number = talloc_asprintf(msg, "%s%s",
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entry->replace,
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&smsc_addr[matches[1].rm_so]);
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if (new_number)
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break;
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}
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if (!new_number)
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return NULL;
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/*
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* We need to re-create the patched structure. This is why we have
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* saved the above pointers.
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*/
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out = msgb_alloc_headroom(4096, 128, "changed-smsc");
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if (!out) {
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LOGP(DNAT, LOGL_ERROR, "Failed to allocate.\n");
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return NULL;
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}
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out->l3h = out->data;
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msgb_v_put(out, GSM411_MT_RP_DATA_MO);
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msgb_v_put(out, ref);
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msgb_lv_put(out, orig_addr_len, orig_addr_ptr);
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/*
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* Copy the new number. We let libosmocore encode it, then set
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* the extension followed after the length. For our convenience
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* we let the TLV code re-add the length so we start copying
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* from &new_addr[1].
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*/
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new_addr_len = gsm48_encode_bcd_number(new_addr, ARRAY_SIZE(new_addr),
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1, new_number);
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new_addr[1] = 0x91;
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msgb_lv_put(out, new_addr_len - 1, new_addr + 1);
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msgb_lv_put(out, data_len, data_ptr);
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new_hdr48 = (struct gsm48_hdr *) msgb_push(out, sizeof(*hdr48) + 1);
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memcpy(new_hdr48, hdr48, sizeof(*hdr48));
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new_hdr48->data[0] = msgb_l3len(out);
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talloc_free(new_number);
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return out;
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}
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struct msgb *bsc_nat_rewrite_msg(struct bsc_nat *nat, struct msgb *msg, struct bsc_nat_parsed *parsed, const char *imsi)
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{
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struct gsm48_hdr *hdr48;
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@ -944,6 +1070,8 @@ struct msgb *bsc_nat_rewrite_msg(struct bsc_nat *nat, struct msgb *msg, struct b
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if (proto == GSM48_PDISC_CC && msg_type == GSM48_MT_CC_SETUP)
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new_msg = rewrite_setup(nat, msg, parsed, imsi, hdr48, len);
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else if (proto == GSM48_PDISC_SMS && msg_type == GSM411_MT_CP_DATA)
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new_msg = rewrite_smsc(nat, msg, parsed, imsi, hdr48, len);
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if (!new_msg)
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return msg;
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@ -973,13 +1101,14 @@ static void num_rewr_free_data(struct bsc_nat_num_rewr_entry *entry)
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talloc_free(entry->replace);
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}
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void bsc_nat_num_rewr_entry_adapt(struct bsc_nat *nat, const struct osmo_config_list *list)
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void bsc_nat_num_rewr_entry_adapt(void *ctx, struct llist_head *head,
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const struct osmo_config_list *list)
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{
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struct bsc_nat_num_rewr_entry *entry, *tmp;
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struct osmo_config_entry *cfg_entry;
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/* free the old data */
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llist_for_each_entry_safe(entry, tmp, &nat->num_rewr, list) {
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llist_for_each_entry_safe(entry, tmp, head, list) {
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num_rewr_free_data(entry);
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llist_del(&entry->list);
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talloc_free(entry);
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@ -997,7 +1126,7 @@ void bsc_nat_num_rewr_entry_adapt(struct bsc_nat *nat, const struct osmo_config_
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continue;
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}
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entry = talloc_zero(nat, struct bsc_nat_num_rewr_entry);
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entry = talloc_zero(ctx, struct bsc_nat_num_rewr_entry);
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if (!entry) {
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LOGP(DNAT, LOGL_ERROR,
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"Allication of the num_rewr entry failed.\n");
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@ -1047,6 +1176,6 @@ void bsc_nat_num_rewr_entry_adapt(struct bsc_nat *nat, const struct osmo_config_
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}
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/* we have copied the number */
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llist_add_tail(&entry->list, &nat->num_rewr);
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llist_add_tail(&entry->list, head);
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}
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}
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@ -466,11 +466,11 @@ DEFUN(cfg_nat_number_rewrite,
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bsc_replace_string(_nat, &_nat->num_rewr_name, argv[0]);
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if (_nat->num_rewr_name) {
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rewr = osmo_config_list_parse(_nat, _nat->num_rewr_name);
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bsc_nat_num_rewr_entry_adapt(_nat, rewr);
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bsc_nat_num_rewr_entry_adapt(_nat, &_nat->num_rewr, rewr);
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talloc_free(rewr);
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return CMD_SUCCESS;
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} else {
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bsc_nat_num_rewr_entry_adapt(_nat, NULL);
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bsc_nat_num_rewr_entry_adapt(_nat, &_nat->num_rewr, NULL);
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return CMD_SUCCESS;
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}
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}
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@ -96,6 +96,28 @@ static const uint8_t id_resp[] = {
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0x31
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};
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/* sms code msg */
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static const uint8_t smsc_rewrite[] = {
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0x00, 0x30, 0xfd, 0x06, 0x01, 0x13, 0x1e, 0x00,
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0x01, 0x29, 0x01, 0x03, 0x26, 0x09, 0x01, 0x23,
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0x00, 0x0c, 0x00, 0x07, 0x91, 0x36, 0x19, 0x08,
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0x00, 0x10, 0x50, 0x17, 0x01, 0x0c, 0x0f, 0x81,
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0x00, 0x94, 0x51, 0x87, 0x86, 0x78, 0x46, 0xf5,
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0x00, 0x00, 0x09, 0xcc, 0xb7, 0xbd, 0x0c, 0xca,
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0xbf, 0xeb, 0x20
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};
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static const uint8_t smsc_rewrite_patched[] = {
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0x00, 0x31, 0xfd, 0x06, 0x01, 0x13, 0x1e, 0x00,
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0x01, 0x2a, 0x01, 0x00, 0x27, 0x09, 0x01, 0x24,
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0x00, 0x0c, 0x00, 0x08, 0x91, 0x66, 0x66, 0x66,
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0x66, 0x66, 0x66, 0xf7, 0x17, 0x01, 0x0c, 0x0f,
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0x81, 0x00, 0x94, 0x51, 0x87, 0x86, 0x78, 0x46,
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0xf5, 0x00, 0x00, 0x09, 0xcc, 0xb7, 0xbd, 0x0c,
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0xca, 0xbf, 0xeb, 0x20
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};
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/*
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* MGCP messages
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*/
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@ -854,7 +854,7 @@ static void test_setup_rewrite()
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entry.option = "^0([1-9])";
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entry.text = "0049";
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llist_add_tail(&entry.list, &entries.entry);
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bsc_nat_num_rewr_entry_adapt(nat, &entries);
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bsc_nat_num_rewr_entry_adapt(nat, &nat->num_rewr, &entries);
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/* verify that nothing changed */
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msgb_reset(msg);
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@ -917,7 +917,7 @@ static void test_setup_rewrite()
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/* Make sure that a wildcard is matching */
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entry.mnc = "*";
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bsc_nat_num_rewr_entry_adapt(nat, &entries);
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bsc_nat_num_rewr_entry_adapt(nat, &nat->num_rewr, &entries);
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msg = msgb_alloc(4096, "test_dt_filter");
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copy_to_msg(msg, cc_setup_national, ARRAY_SIZE(cc_setup_national));
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parsed = bsc_nat_parse(msg);
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@ -952,7 +952,7 @@ static void test_setup_rewrite()
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/* Make sure that a wildcard is matching */
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entry.mnc = "09";
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bsc_nat_num_rewr_entry_adapt(nat, &entries);
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bsc_nat_num_rewr_entry_adapt(nat, &nat->num_rewr, &entries);
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msg = msgb_alloc(4096, "test_dt_filter");
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copy_to_msg(msg, cc_setup_national, ARRAY_SIZE(cc_setup_national));
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parsed = bsc_nat_parse(msg);
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@ -980,6 +980,49 @@ static void test_setup_rewrite()
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msgb_free(out);
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}
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static void test_smsc_rewrite()
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{
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struct msgb *msg = msgb_alloc(4096, "SMSC rewrite"), *out;
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struct bsc_nat_parsed *parsed;
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const char *imsi = "515039900406700";
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struct bsc_nat *nat = bsc_nat_alloc();
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/* a fake list */
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struct osmo_config_list entries;
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struct osmo_config_entry entry;
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INIT_LLIST_HEAD(&entries.entry);
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entry.mcc = "^515039";
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entry.option = "639180000105()";
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entry.text = "6666666666667";
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llist_add_tail(&entry.list, &entries.entry);
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bsc_nat_num_rewr_entry_adapt(nat, &nat->smsc_rewr, &entries);
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copy_to_msg(msg, smsc_rewrite, ARRAY_SIZE(smsc_rewrite));
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parsed = bsc_nat_parse(msg);
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if (!parsed) {
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fprintf(stderr, "FAIL: Could not parse SMS\n");
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abort();
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}
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out = bsc_nat_rewrite_msg(nat, msg, parsed, imsi);
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if (out == msg) {
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fprintf(stderr, "FAIL: This should have changed.\n");
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abort();
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}
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if (out->len != ARRAY_SIZE(smsc_rewrite_patched)) {
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fprintf(stderr, "FAIL: The size should match.\n");
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abort();
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}
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if (memcmp(out->data, smsc_rewrite_patched, out->len) != 0) {
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fprintf(stderr, "FAIL: the data should be changed.\n");
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abort();
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}
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}
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int main(int argc, char **argv)
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{
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sccp_set_log_area(DSCCP);
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@ -995,6 +1038,7 @@ int main(int argc, char **argv)
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test_cr_filter();
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test_dt_filter();
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test_setup_rewrite();
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test_smsc_rewrite();
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test_mgcp_allocations();
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return 0;
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}
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