nat: Prepare to patch more than the CC Setup message
Refactor the code to allow having different handlers. The goal
is to be able to patch some SMS messages too.
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
index a7b0044..47eaabd 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -838,39 +838,19 @@
/**
* 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)
+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;
- struct gsm48_hdr *hdr48;
- uint32_t len;
- uint8_t msg_type, proto;
unsigned int payload_len;
struct gsm_mncc_number called;
- char *new_number = NULL;
struct msgb *out, *sccp;
+ char *new_number = NULL;
uint8_t *outptr;
const uint8_t *msgptr;
int sec_len;
- 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;
-
- proto = hdr48->proto_discr & 0x0f;
- msg_type = hdr48->msg_type & 0xbf;
- if (proto != 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);
@@ -957,6 +937,33 @@
return sccp;
}
+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;
+
+ 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;
+
+ proto = hdr48->proto_discr & 0x0f;
+ msg_type = hdr48->msg_type & 0xbf;
+
+ if (proto == GSM48_PDISC_CC && msg_type == GSM48_MT_CC_SETUP)
+ return rewrite_setup(nat, msg, parsed, imsi, hdr48, len);
+
+ return msg;
+}
static void num_rewr_free_data(struct bsc_nat_num_rewr_entry *entry)
{
regfree(&entry->msisdn_reg);