nat: Implement a post-routing for the NAT software
* The post-routing is applied after the first re-writing. To do this
the new number is copied back into the called data structure.
* Add a testcase that goes from 0172 to 0049 and then back to 0049
using the post rule with a table lookup.
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_rewrite.c b/openbsc/src/osmo-bsc_nat/bsc_nat_rewrite.c
index 5984d96..3bc602e 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_rewrite.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_rewrite.c
@@ -93,8 +93,9 @@
return new_number;
}
-static char *rewrite_isdn_number(struct bsc_nat *nat, void *ctx, const char *imsi,
- struct gsm_mncc_number *called)
+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;
@@ -114,9 +115,22 @@
}
return match_and_rewrite_number(ctx, number,
- imsi, &nat->num_rewr, nat->num_rewr_trie);
+ 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;
+ strncpy(called->number, chosen_number + 2, sizeof(called->number));
+ } else {
+ /* rewrite international to unknown */
+ if (called->type == 1)
+ called->type = 0;
+ strncpy(called->number, chosen_number, sizeof(called->number));
+ }
+}
/**
* Rewrite non global numbers... according to rules based on the IMSI
@@ -129,7 +143,7 @@
unsigned int payload_len;
struct gsm_mncc_number called;
struct msgb *out;
- char *new_number = NULL;
+ char *new_number_pre = NULL, *new_number_post = NULL, *chosen_number;
uint8_t *outptr;
const uint8_t *msgptr;
int sec_len;
@@ -147,16 +161,30 @@
TLVP_VAL(&tp, GSM48_IE_CALLED_BCD) - 1);
/* check if it looks international and stop */
- new_number = rewrite_isdn_number(nat, msg, imsi, &called);
+ new_number_pre = rewrite_isdn_number(nat, &nat->num_rewr, msg, imsi, &called);
- if (!new_number) {
+ if (!new_number_pre) {
LOGP(DNAT, LOGL_DEBUG, "No IMSI match found, returning message.\n");
return NULL;
}
- if (strlen(new_number) > sizeof(called.number)) {
+ if (strlen(new_number_pre) > sizeof(called.number)) {
LOGP(DNAT, LOGL_ERROR, "Number is too long for structure.\n");
- talloc_free(new_number);
+ talloc_free(new_number_pre);
+ return NULL;
+ }
+ update_called_number(&called, new_number_pre);
+
+ /* another run through the re-write engine with other rules */
+ 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(DNAT, LOGL_ERROR, "Number is too long for structure.\n");
+ talloc_free(new_number_pre);
+ talloc_free(new_number_post);
return NULL;
}
@@ -169,7 +197,8 @@
out = msgb_alloc_headroom(4096, 128, "changed-setup");
if (!out) {
LOGP(DNAT, LOGL_ERROR, "Failed to allocate.\n");
- talloc_free(new_number);
+ talloc_free(new_number_pre);
+ talloc_free(new_number_post);
return NULL;
}
@@ -183,15 +212,7 @@
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 {
- /* rewrite international to unknown */
- if (called.type == 1)
- called.type = 0;
- strncpy(called.number, new_number, sizeof(called.number));
- }
+ update_called_number(&called, chosen_number);
gsm48_encode_called(out, &called);
/* copy thre rest */
@@ -201,7 +222,8 @@
outptr = msgb_put(out, sec_len);
memcpy(outptr, msgptr, sec_len);
- talloc_free(new_number);
+ talloc_free(new_number_pre);
+ talloc_free(new_number_post);
return out;
}