/**@internal
*
* Detect NAT.
*
* Based on "received" and possible "rport" parameters in the top-most Via,
* check and update our NAT status.
*
* @retval ob_nat_changed (2) change in public NAT binding detected
* @retval ob_nat_detected (1) NAT binding detected
* @retval ob_no_nat (0) no NAT binding detected
* @retval -1 an error occurred
*/
static
int outbound_nat_detect(outbound_t *ob,
sip_t const *request,
sip_t const *response)
{
sip_via_t const *v;
int one = 1;
char const *received, *rport;
char *nat_detected, *nat_port;
char *new_detected, *new_port;
assert(request && request->sip_request);
assert(response && response->sip_status);
if (!ob || !response || !response->sip_via || !request->sip_via)
return -1;
v = response->sip_via;
received = v->v_received;
if (!received || !strcmp(received, request->sip_via->v_host))
return 0;
if (!host_is_ip_address(received)) {
if (received[0])
SU_DEBUG_3(("outbound(%p): Via with invalid received=%s\n",
(void *)ob->ob_owner, received));
return 0;
}
rport = sip_via_port(v, &one); assert(rport);
nat_detected = ob->ob_nat_detected;
nat_port = ob->ob_nat_port;
if (nat_detected && host_cmp(received, nat_detected) == 0) {
if (nat_port && su_casematch(rport, nat_port))
return 1;
if (!v->v_rport || !v->v_rport[0])
return 1;
}
if (!nat_detected) {
SU_DEBUG_5(("outbound(%p): detected NAT: %s != %s\n",
(void *)ob->ob_owner, v->v_host, received));
if (ob->ob_oo && ob->ob_oo->oo_status)
ob->ob_oo->oo_status(ob->ob_owner, ob, 101, "NAT detected", TAG_END());
}
else {
SU_DEBUG_5(("outbound(%p): NAT binding changed: "
"[%s]:%s != [%s]:%s\n",
(void *)ob->ob_owner, nat_detected, nat_port, received, rport));
if (ob->ob_oo && ob->ob_oo->oo_status)
ob->ob_oo->oo_status(ob->ob_owner, ob, 102, "NAT binding changed", TAG_END());
}
/* Save our nat binding */
new_detected = su_strdup(ob->ob_home, received);
new_port = su_strdup(ob->ob_home, rport);
if (!new_detected || !new_port) {
su_free(ob->ob_home, new_detected);
su_free(ob->ob_home, new_port);
return -1;
}
ob->ob_nat_detected = new_detected;
ob->ob_nat_port = new_port;
su_free(ob->ob_home, nat_detected);
su_free(ob->ob_home, nat_port);
return 2;
}
/** Convert a @Via header to @Contact URL string.
*
* The @Contact URI will contain the port number and transport parameters if
* needed. If transport protocol name starts with "TLS", "SIPS:" URI schema
* is used.
*
* The contact URI string returned will always have angle brackets ("<" and
* ">") around it.
*
* @param home memory home
* @param v @Via header field structure
* (with <sent-by> parameter containing host and port)
* @param user username for @Contact URI (may be NULL)
* @param transport transport name for @Contact URI (may be NULL)
*
* @retval string containing Contact URI with angle brackets
* @retval NULL upon an error
*/
char *
sip_contact_string_from_via(su_home_t *home,
sip_via_t const *v,
char const *user,
char const *transport)
{
const char *host, *port, *maddr, *comp;
char const *scheme = "sip:";
int one = 1;
char _transport[16];
if (!v) return NULL;
host = v->v_host;
if (v->v_received)
host = v->v_received;
port = sip_via_port(v, &one);
maddr = v->v_maddr;
comp = v->v_comp;
if (host == NULL)
return NULL;
if (sip_transport_has_tls(v->v_protocol) ||
sip_transport_has_tls(transport)) {
scheme = "sips:";
if (port && strcmp(port, SIPS_DEFAULT_SERV) == 0)
port = NULL;
if (port || host_is_ip_address(host))
transport = NULL;
}
else if (port && strcmp(port, SIP_DEFAULT_SERV) == 0 &&
(host_is_ip_address(host) || host_has_domain_invalid(host))) {
port = NULL;
}
if (su_casenmatch(transport, "SIP/2.0/", 8))
transport += 8;
/* Make transport parameter lowercase */
if (transport && strlen(transport) < (sizeof _transport)) {
char *s = strcpy(_transport, transport);
short c;
for (s = _transport; (c = *s) && c != ';'; s++)
if (isupper(c))
*s = tolower(c);
transport = _transport;
}
return su_strcat_all(home,
"<",
scheme,
user ? user : "", user ? "@" : "",
host,
SIP_STRLOG(":", port),
SIP_STRLOG(";transport=", transport),
SIP_STRLOG(";maddr=", maddr),
SIP_STRLOG(";comp=", comp),
">",
NULL);
}
