/*
* PROXY_REWRITE_INVITATION_BODY
*
* rewrites the outgoing INVITATION request or response packet
*
* RETURNS
* STS_SUCCESS on success
* STS_FAILURE on error
*/
int proxy_rewrite_invitation_body(osip_message_t *mymsg, int direction){
osip_body_t *body;
sdp_message_t *sdp;
struct in_addr map_addr, addr_sess, addr_media, outside_addr, inside_addr;
int sts;
char *bodybuff;
int bodybuflen;
char clen[8]; /* content length: probably never more than 7 digits !*/
int map_port, msg_port;
int media_stream_no;
sdp_connection_t *sdp_conn;
sdp_media_t *sdp_med;
int rtp_direction=0;
int have_c_media=0;
if (configuration.rtp_proxy_enable == 0) return STS_SUCCESS;
/*
* get SDP structure
*/
sts = osip_message_get_body(mymsg, 0, &body);
if (sts != 0) {
#if 0
if ((MSG_IS_RESPONSE_FOR(mymsg,"INVITE")) &&
(MSG_IS_STATUS_1XX(mymsg))) {
/* 1xx responses *MAY* contain SDP data */
DEBUGC(DBCLASS_PROXY, "rewrite_invitation_body: "
"no body found in message");
return STS_SUCCESS;
} else {
/* INVITE request and 200 response *MUST* contain SDP data */
ERROR("rewrite_invitation_body: no body found in message");
return STS_FAILURE;
}
#else
DEBUGC(DBCLASS_PROXY, "rewrite_invitation_body: "
"no body found in message");
return STS_SUCCESS;
#endif
}
sts = sip_body_to_str(body, &bodybuff, &bodybuflen);
if (sts != 0) {
ERROR("rewrite_invitation_body: unable to sip_body_to_str");
}
sts = sdp_message_init(&sdp);
sts = sdp_message_parse (sdp, bodybuff);
if (sts != 0) {
ERROR("rewrite_invitation_body: unable to sdp_message_parse body");
DUMP_BUFFER(-1, bodybuff, bodybuflen);
osip_free(bodybuff);
sdp_message_free(sdp);
return STS_FAILURE;
}
osip_free(bodybuff);
if (configuration.debuglevel)
{ /* just dump the buffer */
char *tmp, *tmp2;
int tmplen;
sts = osip_message_get_body(mymsg, 0, &body);
sts = sip_body_to_str(body, &tmp, &tmplen);
osip_content_length_to_str(mymsg->content_length, &tmp2);
DEBUG("Body before rewrite (clen=%s, strlen=%i):\n%s\n----",
tmp2, tmplen, tmp);
osip_free(tmp);
osip_free(tmp2);
}
/*
* RTP proxy: get ready and start forwarding
* start forwarding for each media stream ('m=' item in SIP message)
*/
/* get outbound address */
if (get_interface_ip(IF_OUTBOUND, &outside_addr) != STS_SUCCESS) {
sdp_message_free(sdp);
return STS_FAILURE;
}
/* get inbound address */
if (get_interface_ip(IF_INBOUND, &inside_addr) != STS_SUCCESS) {
sdp_message_free(sdp);
return STS_FAILURE;
}
/* figure out what address to use for RTP masquerading */
if (MSG_IS_REQUEST(mymsg)) {
if (direction == DIR_INCOMING) {
memcpy(&map_addr, &inside_addr, sizeof (map_addr));
rtp_direction = DIR_OUTGOING;
} else {
memcpy(&map_addr, &outside_addr, sizeof (map_addr));
rtp_direction = DIR_INCOMING;
}
} else /* MSG_IS_REPONSE(mymsg) */ {
if (direction == DIR_INCOMING) {
memcpy(&map_addr, &inside_addr, sizeof (map_addr));
rtp_direction = DIR_OUTGOING;
} else {
memcpy(&map_addr, &outside_addr, sizeof (map_addr));
rtp_direction = DIR_INCOMING;
}
}
DEBUGC(DBCLASS_PROXY, "proxy_rewrite_invitation_body: SIP[%s %s] RTP[%s %s]",
MSG_IS_REQUEST(mymsg)? "RQ" : "RS",
(direction==DIR_INCOMING)? "IN" : "OUT",
(rtp_direction==DIR_INCOMING)? "IN" : "OUT",
utils_inet_ntoa(map_addr));
/*
* first, check presence of a 'c=' item on session level
*/
if (sdp->c_connection==NULL || sdp->c_connection->c_addr==NULL) {
/*
* No 'c=' on session level, search on media level now
*
* According to RFC2327, ALL media description must
* include a 'c=' item now:
*/
media_stream_no=0;
while (!sdp_message_endof_media(sdp, media_stream_no)) {
/* check if n'th media stream is present */
if (sdp_message_c_addr_get(sdp, media_stream_no, 0) == NULL) {
ERROR("SDP: have no 'c=' on session level and neither "
"on media level (media=%i)",media_stream_no);
sdp_message_free(sdp);
return STS_FAILURE;
}
media_stream_no++;
} /* while */
}
/* Required 'c=' items ARE present */
/*
* rewrite 'c=' item on session level if present and not yet done.
* remember the original address in addr_sess
*/
memset(&addr_sess, 0, sizeof(addr_sess));
if (sdp->c_connection && sdp->c_connection->c_addr) {
sts = get_ip_by_host(sdp->c_connection->c_addr, &addr_sess);
if (sts == STS_FAILURE) {
ERROR("SDP: cannot resolve session 'c=' host [%s]",
sdp->c_connection->c_addr);
sdp_message_free(sdp);
return STS_FAILURE;
}
/*
* Rewrite
* an IP address of 0.0.0.0 means *MUTE*, don't rewrite such
*/
if (strcmp(sdp->c_connection->c_addr, "0.0.0.0") != 0) {
osip_free(sdp->c_connection->c_addr);
sdp->c_connection->c_addr=osip_malloc(HOSTNAME_SIZE);
sprintf(sdp->c_connection->c_addr, "%s", utils_inet_ntoa(map_addr));
} else {
/* 0.0.0.0 - don't rewrite */
DEBUGC(DBCLASS_PROXY, "proxy_rewrite_invitation_body: "
"got a MUTE c= record (on session level - legal?)");
}
}
/*
* rewrite 'o=' item (originator) on session level if present.
*/
if (sdp->o_addrtype && sdp->o_addr) {
if (strcmp(sdp->o_addrtype, "IP4") != 0) {
ERROR("got IP6 in SDP originator - not yet suported by siproxd");
sdp_message_free(sdp);
return STS_FAILURE;
}
osip_free(sdp->o_addr);
sdp->o_addr=osip_malloc(HOSTNAME_SIZE);
sprintf(sdp->o_addr, "%s", utils_inet_ntoa(map_addr));
}
/*
* loop through all media descritions,
* start RTP proxy and rewrite them
*/
for (media_stream_no=0;;media_stream_no++) {
/* check if n'th media stream is present */
if (sdp_message_m_port_get(sdp, media_stream_no) == NULL) break;
/*
* check if a 'c=' item is present in this media description,
* if so -> rewrite it
*/
memset(&addr_media, 0, sizeof(addr_media));
have_c_media=0;
sdp_conn=sdp_message_connection_get(sdp, media_stream_no, 0);
if (sdp_conn && sdp_conn->c_addr) {
if (strcmp(sdp_conn->c_addr, "0.0.0.0") != 0) {
sts = get_ip_by_host(sdp_conn->c_addr, &addr_media);
have_c_media=1;
/* have a valid address */
osip_free(sdp_conn->c_addr);
sdp_conn->c_addr=osip_malloc(HOSTNAME_SIZE);
sprintf(sdp_conn->c_addr, "%s", utils_inet_ntoa(map_addr));
} else {
/* 0.0.0.0 - don't rewrite */
DEBUGC(DBCLASS_PROXY, "proxy_rewrite_invitation_body: got a "
"MUTE c= record (media level)");
}
}
/* start an RTP proxying stream */
if (sdp_message_m_port_get(sdp, media_stream_no)) {
msg_port=atoi(sdp_message_m_port_get(sdp, media_stream_no));
if (msg_port > 0) {
osip_uri_t *cont_url = NULL;
char *client_id=NULL;
/* try to get some additional UA specific unique ID.
* Try:
* 1) User part of Contact header
* 2) Host part of Contact header (will be different
* between internal UA and external UA)
*/
if (!osip_list_eol(mymsg->contacts, 0))
cont_url = ((osip_contact_t*)(mymsg->contacts->node->element))->url;
if (cont_url) {
client_id=cont_url->username;
if (client_id == NULL) client_id=cont_url->host;
}
/*
* do we have a 'c=' item on media level?
* if not, use the same as on session level
*/
if (have_c_media == 0) {
memcpy(&addr_media, &addr_sess, sizeof(addr_sess));
}
/*
* Am I running in front of the routing device? Then I cannot
* use the external IP to bind a listen socket to, so force
* the use of my inbound IP for listening.
*/
if ((rtp_direction == DIR_INCOMING) &&
(configuration.outbound_host) &&
(strcmp(configuration.outbound_host, "")!=0)) {
DEBUGC(DBCLASS_PROXY, "proxy_rewrite_invitation_body: "
"in-front-of-NAT-Router");
memcpy(&map_addr, &inside_addr, sizeof (map_addr));
}
sts = rtp_start_fwd(osip_message_get_call_id(mymsg),
client_id,
rtp_direction,
media_stream_no,
map_addr, &map_port,
addr_media, msg_port);
if (sts == STS_SUCCESS) {
/* and rewrite the port */
sdp_med=osip_list_get(sdp->m_medias, media_stream_no);
if (sdp_med && sdp_med->m_port) {
osip_free(sdp_med->m_port);
sdp_med->m_port=osip_malloc(8); /* 5 digits, \0 + align */
sprintf(sdp_med->m_port, "%i", map_port);
DEBUGC(DBCLASS_PROXY, "proxy_rewrite_invitation_body: "
"m= rewrote port to [%i]",map_port);
} else {
ERROR("rewriting port in m= failed sdp_med=%p, "
"m_number_of_port=%p", sdp_med, sdp_med->m_port);
}
} /* sts == success */
} /* if msg_port > 0 */
} else {
/* no port defined - skip entry */
WARN("no port defined in m=(media) stream_no=%i", media_stream_no);
continue;
}
} /* for media_stream_no */
/* remove old body */
sts = osip_list_remove(mymsg->bodies, 0);
osip_body_free(body);
/* dump new body */
sdp_message_to_str(sdp, &bodybuff);
bodybuflen=strlen(bodybuff);
/* free sdp structure */
sdp_message_free(sdp);
/* include new body */
sip_message_set_body(mymsg, bodybuff, bodybuflen);
if (sts != 0) {
ERROR("rewrite_invitation_body: unable to sip_message_set_body body");
}
/* free content length resource and include new one*/
osip_content_length_free(mymsg->content_length);
mymsg->content_length=NULL;
sprintf(clen,"%i",bodybuflen);
sts = osip_message_set_content_length(mymsg, clen);
/* free old body */
osip_free(bodybuff);
if (configuration.debuglevel)
{ /* just dump the buffer */
char *tmp, *tmp2;
int tmplen;
sts = osip_message_get_body(mymsg, 0, &body);
sts = sip_body_to_str(body, &tmp, &tmplen);
osip_content_length_to_str(mymsg->content_length, &tmp2);
DEBUG("Body after rewrite (clen=%s, strlen=%i):\n%s\n----",
tmp2, tmplen, tmp);
osip_free(tmp);
osip_free(tmp2);
}
return STS_SUCCESS;
}
/*
* PROXY_REQUEST
*
* RETURNS
* STS_SUCCESS on success
* STS_FAILURE on error
*
* RFC3261
* Section 16.3: Proxy Behavior - Request Validation
* 1. Reasonable Syntax
* 2. URI scheme
* 3. Max-Forwards
* 4. (Optional) Loop Detection
* 5. Proxy-Require
* 6. Proxy-Authorization
*
* Section 16.6: Proxy Behavior - Request Forwarding
* 1. Make a copy of the received request
* 2. Update the Request-URI
* 3. Update the Max-Forwards header field
* 4. Optionally add a Record-route header field value
* 5. Optionally add additional header fields
* 6. Postprocess routing information
* 7. Determine the next-hop address, port, and transport
* 8. Add a Via header field value
* 9. Add a Content-Length header field if necessary
* 10. Forward the new request
* 11. Set timer C
*/
int proxy_request (sip_ticket_t *ticket) {
int i;
int sts;
int type;
struct in_addr sendto_addr;
osip_uri_t *url;
int port;
char *buffer;
int buflen;
osip_message_t *request;
struct sockaddr_in *from;
DEBUGC(DBCLASS_PROXY,"proxy_request");
if (ticket==NULL) {
ERROR("proxy_request: called with NULL ticket");
return STS_FAILURE;
}
request=ticket->sipmsg;
from=&ticket->from;
/*
* RFC 3261, Section 16.4
* Proxy Behavior - Route Information Preprocessing
* (process Route header)
*/
route_preprocess(ticket);
/*
* figure out whether this is an incoming or outgoing request
* by doing a lookup in the registration table.
*/
#define _OLD_DIRECTION_EVALUATION 0
#if _OLD_DIRECTION_EVALUATION
type = 0;
for (i=0; i<URLMAP_SIZE; i++) {
if (urlmap[i].active == 0) continue;
/* incoming request ('to' == 'masq') || (('to' == 'reg') && !REGISTER)*/
if ((compare_url(request->to->url, urlmap[i].masq_url)==STS_SUCCESS) ||
(!MSG_IS_REGISTER(request) &&
(compare_url(request->to->url, urlmap[i].reg_url)==STS_SUCCESS))) {
type=REQTYP_INCOMING;
DEBUGC(DBCLASS_PROXY,"incoming request from %s@%s from outbound",
request->from->url->username? request->from->url->username:"******",
request->from->url->host? request->from->url->host: "*NULL*");
break;
}
/* outgoing request ('from' == 'reg') */
if (compare_url(request->from->url, urlmap[i].reg_url)==STS_SUCCESS) {
type=REQTYP_OUTGOING;
DEBUGC(DBCLASS_PROXY,"outgoing request from %s@%s from inbound",
request->from->url->username? request->from->url->username:"******",
request->from->url->host? request->from->url->host: "*NULL*");
break;
}
}
#else
type = 0;
/*
* did I receive the telegram from a REGISTERED host?
* -> it must be an OUTGOING request
*/
for (i=0; i<URLMAP_SIZE; i++) {
struct in_addr tmp_addr;
if (urlmap[i].active == 0) continue;
if (get_ip_by_host(urlmap[i].true_url->host, &tmp_addr) == STS_FAILURE) {
DEBUGC(DBCLASS_PROXY, "proxy_request: cannot resolve host [%s]",
urlmap[i].true_url);
} else {
DEBUGC(DBCLASS_PROXY, "proxy_request: reghost:%s ip:%s",
urlmap[i].true_url->host, utils_inet_ntoa(from->sin_addr));
if (memcmp(&tmp_addr, &from->sin_addr, sizeof(tmp_addr)) == 0) {
type=REQTYP_OUTGOING;
break;
}
}
}
/*
* is the telegram directed to an internally registered host?
* -> it must be an INCOMING request
*/
if (type == 0) {
for (i=0; i<URLMAP_SIZE; i++) {
if (urlmap[i].active == 0) continue;
/* RFC3261:
* 'To' contains a display name (Bob) and a SIP or SIPS URI
* (sip:[email protected]) towards which the request was originally
* directed. Display names are described in RFC 2822 [3].
*/
/* So this means, that we must check the SIP URI supplied with the
* INVITE method, as this points to the real wanted target.
* Q: does there exist a situation where the SIP URI itself does
* point to "somewhere" but the To: points to the correct UA?
* So for now, we just look at both of them (SIP URI and To: header)
*/
/* incoming request (SIP URI == 'masq') || ((SIP URI == 'reg') && !REGISTER)*/
if ((compare_url(request->req_uri, urlmap[i].masq_url)==STS_SUCCESS) ||
(!MSG_IS_REGISTER(request) &&
(compare_url(request->req_uri, urlmap[i].reg_url)==STS_SUCCESS))) {
type=REQTYP_INCOMING;
break;
}
/* incoming request ('to' == 'masq') || (('to' == 'reg') && !REGISTER)*/
if ((compare_url(request->to->url, urlmap[i].masq_url)==STS_SUCCESS) ||
(!MSG_IS_REGISTER(request) &&
(compare_url(request->to->url, urlmap[i].reg_url)==STS_SUCCESS))) {
type=REQTYP_INCOMING;
break;
}
}
}
#endif
ticket->direction=type;
/*
* logging of passing calls
*/
if (configuration.log_calls) {
osip_uri_t *cont_url = NULL;
if (!osip_list_eol(request->contacts, 0))
cont_url = ((osip_contact_t*)(request->contacts->node->element))->url;
/* INVITE */
if (MSG_IS_INVITE(request)) {
if (cont_url) {
INFO("%s Call from: %s@%s",
(type==REQTYP_INCOMING) ? "Incoming":"Outgoing",
cont_url->username ? cont_url->username:"******",
cont_url->host ? cont_url->host : "*NULL*");
} else {
INFO("%s Call (w/o contact header) from: %s@%s",
(type==REQTYP_INCOMING) ? "Incoming":"Outgoing",
request->from->url->username ?
request->from->url->username:"******",
request->from->url->host ?
request->from->url->host : "*NULL*");
}
/* BYE / CANCEL */
} else if (MSG_IS_BYE(request) || MSG_IS_CANCEL(request)) {
if (cont_url) {
INFO("Ending Call from: %s@%s",
cont_url->username ? cont_url->username:"******",
cont_url->host ? cont_url->host : "*NULL*");
} else {
INFO("Ending Call (w/o contact header) from: %s@%s",
request->from->url->username ?
request->from->url->username:"******",
request->from->url->host ?
request->from->url->host : "*NULL*");
}
}
} /* log_calls */
/*
* RFC 3261, Section 16.6 step 1
* Proxy Behavior - Request Forwarding - Make a copy
*/
/* nothing to do here, copy is ready in 'request'*/
/* get destination address */
url=osip_message_get_uri(request);
switch (type) {
/*
* from an external host to the internal masqueraded host
*/
case REQTYP_INCOMING:
DEBUGC(DBCLASS_PROXY,"incoming request from %s@%s from outbound",
request->from->url->username? request->from->url->username:"******",
request->from->url->host? request->from->url->host: "*NULL*");
/*
* RFC 3261, Section 16.6 step 2
* Proxy Behavior - Request Forwarding - Request-URI
* (rewrite request URI to point to the real host)
*/
/* 'i' still holds the valid index into the URLMAP table */
if (check_rewrite_rq_uri(request) == STS_TRUE) {
proxy_rewrite_request_uri(request, i);
}
/* if this is CANCEL/BYE request, stop RTP proxying */
if (MSG_IS_BYE(request) || MSG_IS_CANCEL(request)) {
/* stop the RTP proxying stream(s) */
rtp_stop_fwd(osip_message_get_call_id(request), DIR_INCOMING);
rtp_stop_fwd(osip_message_get_call_id(request), DIR_OUTGOING);
/* check for incoming request */
} else if (MSG_IS_INVITE(request)) {
/* Rewrite the body */
sts = proxy_rewrite_invitation_body(request, DIR_INCOMING);
} else if (MSG_IS_ACK(request)) {
/* Rewrite the body */
sts = proxy_rewrite_invitation_body(request, DIR_INCOMING);
}
break;
/*
* from the internal masqueraded host to an external host
*/
case REQTYP_OUTGOING:
DEBUGC(DBCLASS_PROXY,"outgoing request from %s@%s from inbound",
request->from->url->username? request->from->url->username:"******",
request->from->url->host? request->from->url->host: "*NULL*");
/*
* RFC 3261, Section 16.6 step 2
* Proxy Behavior - Request Forwarding - Request-URI
*/
/* nothing to do for an outgoing request */
/* if it is addressed to myself, then it must be some request
* method that I as a proxy do not support. Reject */
#if 0
/* careful - an internal UA might send an request to another internal UA.
This would be caught here, so don't do this. This situation should be
caught in the default part of the CASE statement below */
if (is_sipuri_local(ticket) == STS_TRUE) {
WARN("unsupported request [%s] directed to proxy from %s@%s -> %s@%s",
request->sip_method? request->sip_method:"*NULL*",
request->from->url->username? request->from->url->username:"******",
request->from->url->host? request->from->url->host : "*NULL*",
url->username? url->username : "******",
url->host? url->host : "*NULL*");
sip_gen_response(ticket, 403 /*forbidden*/);
return STS_FAILURE;
}
#endif
/* rewrite Contact header to represent the masqued address */
sip_rewrite_contact(ticket, DIR_OUTGOING);
/* if an INVITE, rewrite body */
if (MSG_IS_INVITE(request)) {
sts = proxy_rewrite_invitation_body(request, DIR_OUTGOING);
} else if (MSG_IS_ACK(request)) {
sts = proxy_rewrite_invitation_body(request, DIR_OUTGOING);
}
/* if this is CANCEL/BYE request, stop RTP proxying */
if (MSG_IS_BYE(request) || MSG_IS_CANCEL(request)) {
/* stop the RTP proxying stream(s) */
rtp_stop_fwd(osip_message_get_call_id(request), DIR_INCOMING);
rtp_stop_fwd(osip_message_get_call_id(request), DIR_OUTGOING);
}
break;
default:
DEBUGC(DBCLASS_PROXY, "request [%s] from/to unregistered UA "
"(RQ: %s@%s -> %s@%s)",
request->sip_method? request->sip_method:"*NULL*",
request->from->url->username? request->from->url->username:"******",
request->from->url->host? request->from->url->host : "*NULL*",
url->username? url->username : "******",
url->host? url->host : "*NULL*");
/*
* we may end up here for two reasons:
* 1) An incomming request (from outbound) that is directed to
* an unknown (not registered) local UA
* 2) an outgoing request from a local UA that is not registered.
*
* Case 1) we should probably answer with "404 Not Found",
* case 2) more likely a "403 Forbidden"
*
* How about "408 Request Timeout" ?
*
*/
sip_gen_response(ticket, 408 /* Request Timeout */);
return STS_FAILURE;
}
/*
* RFC 3261, Section 16.6 step 3
* Proxy Behavior - Request Forwarding - Max-Forwards
* (if Max-Forwards header exists, decrement by one, if it does not
* exist, add a new one with value SHOULD be 70)
*/
{
osip_header_t *max_forwards;
int forwards_count = DEFAULT_MAXFWD;
char mfwd[8];
osip_message_get_max_forwards(request, 0, &max_forwards);
if (max_forwards == NULL) {
sprintf(mfwd, "%i", forwards_count);
osip_message_set_max_forwards(request, mfwd);
} else {
if (max_forwards->hvalue) {
forwards_count = atoi(max_forwards->hvalue);
forwards_count -=1;
osip_free (max_forwards->hvalue);
}
sprintf(mfwd, "%i", forwards_count);
max_forwards->hvalue = osip_strdup(mfwd);
}
DEBUGC(DBCLASS_PROXY,"setting Max-Forwards=%s",mfwd);
}
/*
* RFC 3261, Section 16.6 step 4
* Proxy Behavior - Request Forwarding - Add a Record-route header
*/
/*
* for ALL incoming requests, include my Record-Route header.
* The local UA will probably send its answer to the topmost
* Route Header (8.1.2 of RFC3261)
*/
if (type == REQTYP_INCOMING) {
DEBUGC(DBCLASS_PROXY,"Adding my Record-Route");
route_add_recordroute(ticket);
} else {
/*
* outgoing packets must not have my record route header, as
* this likely will contain a private IP address (my inbound).
*/
DEBUGC(DBCLASS_PROXY,"Purging Record-Routes (outgoing packet)");
route_purge_recordroute(ticket);
}
/*
* RFC 3261, Section 16.6 step 5
* Proxy Behavior - Request Forwarding - Add Additional Header Fields
*/
/* NOT IMPLEMENTED (optional) */
/*
* RFC 3261, Section 16.6 step 6
* Proxy Behavior - Request Forwarding - Postprocess routing information
*
* If the copy contains a Route header field, the proxy MUST
* inspect the URI in its first value. If that URI does not
* contain an lr parameter, the proxy MUST modify the copy as
* follows:
*
* - The proxy MUST place the Request-URI into the Route header
* field as the last value.
*
* - The proxy MUST then place the first Route header field value
* into the Request-URI and remove that value from the Route
* header field.
*/
#if 0
route_postprocess(ticket);
#endif
/*
* RFC 3261, Section 16.6 step 7
* Proxy Behavior - Determine Next-Hop Address
*/
/*&&&& priority probably should be:
* 1) Route header
* 2) fixed outbound proxy
* 3) SIP URI
*/
/*
* fixed or domain outbound proxy defined ?
*/
if ((type == REQTYP_OUTGOING) &&
(sip_find_outbound_proxy(ticket, &sendto_addr, &port) == STS_SUCCESS)) {
DEBUGC(DBCLASS_PROXY, "proxy_request: have outbound proxy %s:%i",
utils_inet_ntoa(sendto_addr), port);
/*
* Route present?
* If so, fetch address from topmost Route: header and remove it.
*/
} else if ((type == REQTYP_OUTGOING) &&
(request->routes && !osip_list_eol(request->routes, 0))) {
sts=route_determine_nexthop(ticket, &sendto_addr, &port);
if (sts == STS_FAILURE) {
DEBUGC(DBCLASS_PROXY, "proxy_request: route_determine_nexthop failed");
return STS_FAILURE;
}
DEBUGC(DBCLASS_PROXY, "proxy_request: have Route header to %s:%i",
utils_inet_ntoa(sendto_addr), port);
/*
* destination from SIP URI
*/
} else {
/* get the destination from the SIP URI */
sts = get_ip_by_host(url->host, &sendto_addr);
if (sts == STS_FAILURE) {
DEBUGC(DBCLASS_PROXY, "proxy_request: cannot resolve URI [%s]",
url->host);
return STS_FAILURE;
}
if (url->port) {
port=atoi(url->port);
} else {
port=SIP_PORT;
}
DEBUGC(DBCLASS_PROXY, "proxy_request: have SIP URI to %s:%i",
url->host, port);
}
/*
* RFC 3261, Section 16.6 step 8
* Proxy Behavior - Add a Via header field value
*/
/* add my Via header line (outbound interface)*/
if (type == REQTYP_INCOMING) {
sts = sip_add_myvia(ticket, IF_INBOUND);
if (sts == STS_FAILURE) {
ERROR("adding my inbound via failed!");
}
} else {
sts = sip_add_myvia(ticket, IF_OUTBOUND);
if (sts == STS_FAILURE) {
ERROR("adding my outbound via failed!");
return STS_FAILURE;
}
}
/*
* RFC 3261, Section 16.6 step 9
* Proxy Behavior - Add a Content-Length header field if necessary
*/
/* not necessary, already in message and we do not support TCP */
/*
* RFC 3261, Section 16.6 step 10
* Proxy Behavior - Forward the new request
*/
sts = sip_message_to_str(request, &buffer, &buflen);
if (sts != 0) {
ERROR("proxy_request: sip_message_to_str failed");
return STS_FAILURE;
}
sipsock_send(sendto_addr, port, ticket->protocol,
buffer, buflen);
osip_free (buffer);
/*
* RFC 3261, Section 16.6 step 11
* Proxy Behavior - Set timer C
*/
/* NOT IMPLEMENTED - does this really apply for stateless proxies? */
return STS_SUCCESS;
}
static struct session *sip_callback(struct session *sip, u_char *data, uint32_t len)
{
osip_message_t *msg;
struct tuple4 addr;
struct session *start;
struct session *rtp;
osip_call_id_t *call_id;
osip_message_init(&msg);
if (!osip_message_parse(msg, (char *)data, len)) {
if (NULL == sip->u.sip_params.call_id) {
/*
* If the session object was created by udp_callback
* we need to fill in the call_id field here because
* udp_callback doesn't know anything about SIP
*/
if (NULL != (call_id = osip_message_get_call_id(msg)))
osip_call_id_clone(call_id, &sip->u.sip_params.call_id);
} else {
/*
* Otherwise check if the session object passed to this
* function call was really the one corresponding to the
* call ID in the SIP packet, in case several SIP calls
* are passed upon the same transport layer protocol,
* source and destination IPv4 address & port combination.
* udp_callback has no way of knowing how to distinguish
* SIP session objects based on call ID, so we have to do
* it here. We just continue searching in the list of all
* tracked sessions for similar SIP objects until we find
* one that has the same call ID, or else we create a new
* SIP session object that corresponds to the new call.
*/
start = sip;
do {
if (NULL == (call_id = osip_message_get_call_id(msg)))
continue;
if (!osip_call_id_match(sip->u.sip_params.call_id, call_id))
break;
} while ((sip = sessions_find(sip->next, TYPE_SIP, 0, &sip->addr)));
if (NULL == sip) {
if (bonus_time) {
osip_message_free(msg);
return start;
}
sip = sessions_add(start->type, &start->addr, NULL);
if (NULL != (call_id = osip_message_get_call_id(msg)))
osip_call_id_clone(call_id, &sip->u.sip_params.call_id);
}
}
/*
* If the current SIP packet is an INVITE message, store the
* advertised source port and IPv4 address. It is not very
* important, since we can do only with the destination part
* (useful in case the capture missed the INVITE packet), but
* it helps discriminating from unrelated packets.
*
* Unfortunately, some SIP implementations such as the one in
* Audiocodes Mediant 1000 SIP gateways actually use a source
* port different from the one they advertised in the INVITE
* message parameters - how outrageous! - so we have to make
* our sessions search engine ignore the source port part by
* zeroing it :-/
*/
if (MSG_IS_INVITE(msg)) {
if (!bonus_time) {
sip_get_address(msg, &sip->u.sip_params.rtp_addr.saddr, &sip->u.sip_params.rtp_addr.source);
#ifndef USING_NON_STUPID_SIP_IMPLEMENTATIONS
sip->u.sip_params.rtp_addr.source = 0;
#endif
}
} else
if (MSG_TEST_CODE(msg, 200)) {
if (MSG_IS_RESPONSE_FOR(msg, "INVITE")) {
if (!bonus_time && sip_get_address(msg, &sip->u.sip_params.rtp_addr.daddr, &sip->u.sip_params.rtp_addr.dest)) {
sessions_add(TYPE_UDP | TYPE_RTP, &sip->u.sip_params.rtp_addr, sip);
sip->u.sip_params.picked_up = 1;
}
} else
if (MSG_IS_RESPONSE_FOR(msg, "BYE") ||
MSG_IS_RESPONSE_FOR(msg, "CANCEL")) {
start = first_session;
while (NULL != (rtp = sessions_find(start, TYPE_RTP, sip->id, NULL))) {
sessions_del(rtp);
start = rtp->next;
}
/*
* Mark for deletion in 2 seconds, in order to give some
* time to the extra ACK packets that might be exchanged
*/
if (sip->type & TYPE_UDP)
sip->timeout = nids_last_pcap_header->ts.tv_sec + 2;
}
}
}
osip_message_free(msg);
return sip;
}
/*
* PROXY_RESPONSE
*
* RETURNS
* STS_SUCCESS on success
* STS_FAILURE on error
* RFC3261
* Section 16.7: Proxy Behavior - Response Processing
* 1. Find the appropriate response context
* 2. Update timer C for provisional responses
* 3. Remove the topmost Via
* 4. Add the response to the response context
* 5. Check to see if this response should be forwarded immediately
* 6. When necessary, choose the best final response from the
* response context
* 7. Aggregate authorization header field values if necessary
* 8. Optionally rewrite Record-Route header field values
* 9. Forward the response
* 10. Generate any necessary CANCEL requests
*
*/
int proxy_response (sip_ticket_t *ticket) {
int i;
int sts;
int type;
struct in_addr sendto_addr;
osip_via_t *via;
int port;
char *buffer;
int buflen;
osip_message_t *response;
struct sockaddr_in *from;
DEBUGC(DBCLASS_PROXY,"proxy_response");
if (ticket==NULL) {
ERROR("proxy_response: called with NULL ticket");
return STS_FAILURE;
}
response=ticket->sipmsg;
from=&ticket->from;
/*
* RFC 3261, Section 16.7 step 3
* Proxy Behavior - Response Processing - Remove my Via header field value
*/
/* remove my Via header line */
sts = sip_del_myvia(ticket);
if (sts == STS_FAILURE) {
DEBUGC(DBCLASS_PROXY,"not addressed to my VIA, ignoring response");
return STS_FAILURE;
}
/*
* figure out if this is an request coming from the outside
* world to one of our registered clients
*/
/* Ahhrghh...... a response seems to have NO contact information...
* so let's take FROM instead...
* the TO and FROM headers are EQUAL to the request - that means
* they are swapped in their meaning for a response...
*/
#if _OLD_DIRECTION_EVALUATION
type = 0;
for (i=0; i<URLMAP_SIZE; i++) {
if (urlmap[i].active == 0) continue;
/* incoming response ('from' == 'masq') || ('from' == 'reg') */
if ((compare_url(response->from->url, urlmap[i].reg_url)==STS_SUCCESS) ||
(compare_url(response->from->url, urlmap[i].masq_url)==STS_SUCCESS)) {
type=RESTYP_INCOMING;
DEBUGC(DBCLASS_PROXY,"incoming response for %s@%s from outbound",
response->from->url->username? response->from->url->username:"******",
response->from->url->host? response->from->url->host : "*NULL*");
break;
}
/* outgoing response ('to' == 'reg') || ('to' == 'masq' ) */
if ((compare_url(response->to->url, urlmap[i].masq_url)==STS_SUCCESS) ||
(compare_url(response->to->url, urlmap[i].reg_url)==STS_SUCCESS)){
type=RESTYP_OUTGOING;
DEBUGC(DBCLASS_PROXY,"outgoing response for %s@%s from inbound",
response->from->url->username ?
response->from->url->username : "******",
response->from->url->host ?
response->from->url->host : "*NULL*");
break;
}
}
#else
type = 0;
/*
* did I receive the telegram from a REGISTERED host?
* -> it must be an OUTGOING response
*/
for (i=0; i<URLMAP_SIZE; i++) {
struct in_addr tmp_addr;
if (urlmap[i].active == 0) continue;
if (get_ip_by_host(urlmap[i].true_url->host, &tmp_addr) == STS_FAILURE) {
DEBUGC(DBCLASS_PROXY, "proxy_response: cannot resolve host [%s]",
urlmap[i].true_url);
} else {
DEBUGC(DBCLASS_PROXY, "proxy_response: reghost:%s ip:%s",
urlmap[i].true_url->host, utils_inet_ntoa(from->sin_addr));
if (memcmp(&tmp_addr, &from->sin_addr, sizeof(tmp_addr)) == 0) {
type=RESTYP_OUTGOING;
break;
}
}
}
/*
* is the telegram directed to an internal registered host?
* -> it must be an INCOMING response
*/
if (type == 0) {
for (i=0; i<URLMAP_SIZE; i++) {
if (urlmap[i].active == 0) continue;
/* incoming response ('from' == 'masq') || ('from' == 'reg') */
if ((compare_url(response->from->url, urlmap[i].reg_url)==STS_SUCCESS) ||
(compare_url(response->from->url, urlmap[i].masq_url)==STS_SUCCESS)) {
type=RESTYP_INCOMING;
break;
}
}
}
/* &&&& Open Issue &&&&
it has been seen with cross-provider calls that the FROM may be 'garbled'
(e.g [email protected] for calls made sipphone -> FWD)
How can we deal with this? Should I take into consideration the 'Via'
headers? This is the only clue I have, pointing to the *real* UA.
Maybe I should put in a 'siproxd' ftag value to recognize it as a header
inserted by myself
*/
if ((type == 0) && (!osip_list_eol(response->vias, 0))) {
osip_via_t *via;
struct in_addr addr_via, addr_myself;
int port_via, port_ua;
/* get the via address */
via = (osip_via_t *) osip_list_get (response->vias, 0);
DEBUGC(DBCLASS_PROXY, "proxy_response: check via [%s] for "
"registered UA",via->host);
sts=get_ip_by_host(via->host, &addr_via);
if (sts == STS_FAILURE) {
DEBUGC(DBCLASS_DNS, "proxy_response: cannot resolve VIA [%s]",
via->host);
} else {
for (i=0; i<URLMAP_SIZE; i++) {
if (urlmap[i].active == 0) continue;
/* incoming response (1st via in list points to a registered UA) */
sts=get_ip_by_host(urlmap[i].true_url->host, &addr_myself);
if (sts == STS_FAILURE) {
DEBUGC(DBCLASS_DNS, "proxy_response: cannot resolve "
"true_url [%s]", via->host);
continue;
}
port_via=0;
if (via->port) port_via=atoi(via->port);
if (port_via <= 0) port_via=SIP_PORT;
port_ua=0;
if (urlmap[i].true_url->port)
port_ua=atoi(urlmap[i].true_url->port);
if (port_ua <= 0) port_ua=SIP_PORT;
DEBUGC(DBCLASS_BABBLE, "proxy_response: checking for registered "
"host [%s:%i] <-> [%s:%i]",
urlmap[i].true_url->host, port_ua,
via->host, port_via);
if ((memcmp(&addr_myself, &addr_via, sizeof(addr_myself))==0) &&
(port_via == port_ua)) {
type=RESTYP_INCOMING;
break;
}
}
}
}
#endif
ticket->direction=type;
/*
* ok, we got a response that we are allowed to process.
*/
switch (type) {
/*
* from an external host to the internal masqueraded host
*/
case RESTYP_INCOMING:
DEBUGC(DBCLASS_PROXY,"incoming response for %s@%s from outbound",
response->from->url->username? response->from->url->username:"******",
response->from->url->host? response->from->url->host : "*NULL*");
/*
* Response for INVITE - deal with RTP data in body and
* start RTP proxy stream(s). In case
* of a negative answer, stop RTP stream
*/
if (MSG_IS_RESPONSE_FOR(response,"INVITE")) {
/* positive response, start RTP stream */
if ((MSG_IS_STATUS_1XX(response)) ||
(MSG_IS_STATUS_2XX(response))) {
if (configuration.rtp_proxy_enable == 1) {
sts = proxy_rewrite_invitation_body(response, DIR_INCOMING);
}
/* negative - stop a possibly started RTP stream */
} else if ((MSG_IS_STATUS_4XX(response)) ||
(MSG_IS_STATUS_5XX(response)) ||
(MSG_IS_STATUS_6XX(response))) {
rtp_stop_fwd(osip_message_get_call_id(response), DIR_INCOMING);
rtp_stop_fwd(osip_message_get_call_id(response), DIR_OUTGOING);
}
} /* if INVITE */
/*
* Response for REGISTER - special handling of Contact header
*/
if (MSG_IS_RESPONSE_FOR(response,"REGISTER")) {
/*
* REGISTER returns *my* Contact header information.
* Rewrite Contact header back to represent the true address.
* Other responses do return the Contact header of the sender.
*/
sip_rewrite_contact(ticket, DIR_INCOMING);
}
/*
* Response for SUBSCRIBE
*
* HACK for Grandstream SIP phones (with newer firmware like 1.0.4.40):
* They send a SUBSCRIBE request to the registration server. In
* case of beeing registering directly to siproxd, this request of
* course will eventually be forwarded back to the same UA.
* Grandstream then does reply with an '202' response (A 202
* response merely indicates that the subscription has been
* understood, and that authorization may or may not have been
* granted), which then of course is forwarded back to the phone.
* Ans it seems that the Grandstream can *not* *handle* this
* response, as it immediately sends another SUBSCRIBE request.
* And this games goes on and on and on...
*
* As a workaround we will transform any 202 response to a
* '404 unknown destination'
*
*/
{
osip_header_t *ua_hdr=NULL;
osip_message_get_user_agent(response, 0, &ua_hdr);
if (ua_hdr && ua_hdr->hvalue &&
(osip_strncasecmp(ua_hdr->hvalue,"grandstream", 11)==0) &&
(MSG_IS_RESPONSE_FOR(response,"SUBSCRIBE")) &&
(MSG_TEST_CODE(response, 202))) {
DEBUGC(DBCLASS_PROXY, "proxy_response: Grandstream hack 202->404");
response->status_code=404;
}
}
break;
/*
* from the internal masqueraded host to an external host
*/
case RESTYP_OUTGOING:
DEBUGC(DBCLASS_PROXY,"outgoing response for %s@%s from inbound",
response->from->url->username ?
response->from->url->username : "******",
response->from->url->host ?
response->from->url->host : "*NULL*");
/* rewrite Contact header to represent the masqued address */
sip_rewrite_contact(ticket, DIR_OUTGOING);
/*
* If an 2xx OK or 1xx response, answer to an INVITE request,
* rewrite body
*
* In case of a negative answer, stop RTP stream
*/
if (MSG_IS_RESPONSE_FOR(response,"INVITE")) {
/* positive response, start RTP stream */
if ((MSG_IS_STATUS_1XX(response)) ||
(MSG_IS_STATUS_2XX(response))) {
/* This is an outgoing response, therefore an outgoing stream */
sts = proxy_rewrite_invitation_body(response, DIR_OUTGOING);
/* megative - stop a possibly started RTP stream */
} else if ((MSG_IS_STATUS_4XX(response)) ||
(MSG_IS_STATUS_5XX(response)) ||
(MSG_IS_STATUS_6XX(response))) {
rtp_stop_fwd(osip_message_get_call_id(response), DIR_INCOMING);
rtp_stop_fwd(osip_message_get_call_id(response), DIR_OUTGOING);
}
} /* if INVITE */
break;
default:
DEBUGC(DBCLASS_PROXY, "response from/to unregistered UA (%s@%s)",
response->from->url->username? response->from->url->username:"******",
response->from->url->host? response->from->url->host : "*NULL*");
return STS_FAILURE;
}
/*
* for ALL incoming response include my Record-Route header.
* The local UA will probably send its answer to the topmost
* Route Header (8.1.2 of RFC3261)
*/
if (type == RESTYP_INCOMING) {
DEBUGC(DBCLASS_PROXY,"Adding my Record-Route");
route_add_recordroute(ticket);
} else {
/*
* outgoing packets must not have my record route header, as
* this likely will contain a private IP address (my inbound).
*/
DEBUGC(DBCLASS_PROXY,"Purging Record-Routes (outgoing packet)");
route_purge_recordroute(ticket);
}
/*
* Determine Next-Hop Address
*/
/*&&&& priority probably should be:
* 1) Route header
* 2) fixed outbound proxy
* 3) SIP URI
*/
/*
* check if we need to send to an outbound proxy
*/
if ((type == RESTYP_OUTGOING) &&
(sip_find_outbound_proxy(ticket, &sendto_addr, &port) == STS_SUCCESS)) {
DEBUGC(DBCLASS_PROXY, "proxy_response: have outbound proxy %s:%i",
utils_inet_ntoa(sendto_addr), port);
/*
* Route present?
* If so, fetch address from topmost Route: header and remove it.
*/
} else if ((type == RESTYP_OUTGOING) &&
(response->routes && !osip_list_eol(response->routes, 0))) {
sts=route_determine_nexthop(ticket, &sendto_addr, &port);
if (sts == STS_FAILURE) {
DEBUGC(DBCLASS_PROXY, "proxy_response: route_determine_nexthop failed");
return STS_FAILURE;
}
DEBUGC(DBCLASS_PROXY, "proxy_response: have Route header to %s:%i",
utils_inet_ntoa(sendto_addr), port);
} else {
/* get target address and port from VIA header */
via = (osip_via_t *) osip_list_get (response->vias, 0);
if (via == NULL) {
ERROR("proxy_response: list_get via failed");
return STS_FAILURE;
}
sts = get_ip_by_host(via->host, &sendto_addr);
if (sts == STS_FAILURE) {
DEBUGC(DBCLASS_PROXY, "proxy_response: cannot resolve VIA [%s]",
via->host);
return STS_FAILURE;
}
if (via->port) {
port=atoi(via->port);
} else {
port=SIP_PORT;
}
}
sts = sip_message_to_str(response, &buffer, &buflen);
if (sts != 0) {
ERROR("proxy_response: sip_message_to_str failed");
return STS_FAILURE;
}
sipsock_send(sendto_addr, port, ticket->protocol,
buffer, buflen);
osip_free (buffer);
return STS_SUCCESS;
}
/*
* SIP_CALCULATE_BRANCH
*
* Calculates a branch parameter according to RFC3261 section 16.11
*
* The returned 'id' will be HASHHEXLEN + strlen(magic_cookie)
* characters (32 + 7) long. The caller must supply at least this
* amount of space in 'id'.
*
* RETURNS
* STS_SUCCESS on success
* STS_FAILURE on error
*/
int sip_calculate_branch_id (sip_ticket_t *ticket, char *id) {
/* RFC3261 section 16.11 recommends the following procedure:
* The stateless proxy MAY use any technique it likes to guarantee
* uniqueness of its branch IDs across transactions. However, the
* following procedure is RECOMMENDED. The proxy examines the
* branch ID in the topmost Via header field of the received
* request. If it begins with the magic cookie, the first
* component of the branch ID of the outgoing request is computed
* as a hash of the received branch ID. Otherwise, the first
* component of the branch ID is computed as a hash of the topmost
* Via, the tag in the To header field, the tag in the From header
* field, the Call-ID header field, the CSeq number (but not
* method), and the Request-URI from the received request. One of
* these fields will always vary across two different
* transactions.
*
* The branch value will consist of:
* - magic cookie "z9hG4bK"
* - 1st part (unique calculated ID
* - 2nd part (value for loop detection) <<- not yet used by siproxd
*/
osip_message_t *sip_msg=ticket->sipmsg;
static char *magic_cookie="z9hG4bK";
osip_via_t *via;
osip_uri_param_t *param=NULL;
osip_call_id_t *call_id=NULL;
HASHHEX hashstring;
hashstring[0]='\0';
/*
* Examine topmost via and look for a magic cookie.
* If it is there, I use THIS branch parameter as input for
* our hash calculation
*/
via = osip_list_get (sip_msg->vias, 0);
if (via == NULL) {
ERROR("have a SIP message without any via header");
return STS_FAILURE;
}
param=NULL;
osip_via_param_get_byname(via, "branch", ¶m);
if (param && param->gvalue) {
DEBUGC(DBCLASS_BABBLE, "looking for magic cookie [%s]",param->gvalue);
if (strncmp(param->gvalue, magic_cookie,
strlen(magic_cookie))==0) {
/* calculate MD5 hash */
MD5_CTX Md5Ctx;
HASH HA1;
MD5Init(&Md5Ctx);
MD5Update(&Md5Ctx, param->gvalue,
strlen(param->gvalue));
MD5Final(HA1, &Md5Ctx);
CvtHex(HA1, hashstring);
DEBUGC(DBCLASS_BABBLE, "existing branch -> branch hash [%s]",
hashstring);
}
}
/*
* If I don't have a branch parameter in the existing topmost via,
* then I need:
* - the topmost via
* - the tag in the To header field
* - the tag in the From header field
* - the Call-ID header field
* - the CSeq number (but not method)
* - the Request-URI from the received request
*/
if (hashstring[0] == '\0') {
/* calculate MD5 hash */
MD5_CTX Md5Ctx;
HASH HA1;
char *tmp;
MD5Init(&Md5Ctx);
/* topmost via */
osip_via_to_str(via, &tmp);
if (tmp) {
MD5Update(&Md5Ctx, tmp, strlen(tmp));
osip_free(tmp);
}
/* Tag in To header */
osip_to_get_tag(sip_msg->to, ¶m);
if (param && param->gvalue) {
MD5Update(&Md5Ctx, param->gvalue, strlen(param->gvalue));
}
/* Tag in From header */
osip_from_get_tag(sip_msg->from, ¶m);
if (param && param->gvalue) {
MD5Update(&Md5Ctx, param->gvalue, strlen(param->gvalue));
}
/* Call-ID */
call_id = osip_message_get_call_id(sip_msg);
osip_call_id_to_str(call_id, &tmp);
if (tmp) {
MD5Update(&Md5Ctx, tmp, strlen(tmp));
osip_free(tmp);
}
/* CSeq number (but not method) */
tmp = osip_cseq_get_number(sip_msg->cseq);
if (tmp) {
MD5Update(&Md5Ctx, tmp, strlen(tmp));
}
/* Request URI */
osip_uri_to_str(sip_msg->req_uri, &tmp);
if (tmp) {
MD5Update(&Md5Ctx, tmp, strlen(tmp));
osip_free(tmp);
}
MD5Final(HA1, &Md5Ctx);
CvtHex(HA1, hashstring);
DEBUGC(DBCLASS_BABBLE, "non-existing branch -> branch hash [%s]",
hashstring);
}
/* include the magic cookie */
sprintf(id, "%s%s", magic_cookie, hashstring);
return STS_SUCCESS;
}
