Add SIPREC recording support (RFC 7865/7866) to SBC

Implement a SIPREC Session Recording Client (SRC) as an SBC call_control
module (cc_siprec) that forks RTP to a Session Recording Server (SRS),
plus a minimal built-in SRS (siprec_srs) for testing.

SIP signaling (RFC 7866):
- INVITE with Require: siprec and +sip.src Contact feature tag
- multipart/mixed body: SDP offer + metadata XML
- Content-Disposition: recording-session on metadata parts
- Separate sendonly m-lines per CS direction with a=label
- Symmetric RTP with allocated local port pairs (RFC 7866 8.1.8)
- RTCP port allocation on port+1 (RFC 7866 8.1.1)
- Configurable RTP profile: RTP/AVP, RTP/SAVP, RTP/AVPF, RTP/SAVPF
- CANCEL for pending INVITE on call teardown
- re-INVITE for hold/resume with updated SDP + metadata
- BYE with final metadata and stop-time

Metadata XML (RFC 7865):
- Namespace urn:ietf:params:xml:ns:recording:1
- session, participant, stream elements with base64 IDs
- sessionrecordingassoc and participantsessionassoc elements
- participantstreamassoc with send/recv text-content stream refs
- ISO 8601 timestamps, partial updates on hold

Recording indication (RFC 7866 6.1.2):
- a=record:on injected into B-leg INVITE SDP

CS SDP codec extraction:
- Parses initial INVITE SDP to auto-detect codec for RS offer
- Falls back to configured codec (PCMA/PCMU) when unavailable

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

.gitignore

@@ -8,6 +8,7 @@
 *.so
 *.swp
 *~
+.claude
 /CMakeCache.txt
 CMakeFiles/
 CTestTestfile.cmake

README.md

@@ -55,13 +55,29 @@ The following applications are shipped with SEMS :
 
 ### Back-to-back User Agent
 
-* **sbc** - flexible SBC application, supports
-  - identity change
-  - header manipulation (filter etc)
-  - (multihomed) RTP relay, NAT handling, transcoding
-  - SIP authentication 
-  - Session timer, call timer, prepaid
-  - etc
+* **sbc** - flexible SBC (Session Border Controller) application, supports
+  - header manipulation and filtering
+  - (multihomed) RTP relay, NAT handling
+  - audio transcoding with codec mapping
+  - SIP authentication (UAC, A/B leg)
+  - session timer (SST) for both legs
+  - contact hiding and identity change
+  - SIP reply code/reason translation
+  - DTMF filtering and detection
+  - RTP bandwidth limiting
+  - registration caching and retargeting
+  - call_control modules:
+    - **cc_bl_redis** - Redis-based call blacklisting
+    - **cc_call_timer** - call duration limit enforcement
+    - **cc_ctl** - profile control via SIP headers
+    - **cc_dsm** - roles for DSM state machine scripting
+    - **cc_parallel_calls** - concurrent call limiting per user
+    - **cc_prepaid** - local credit-based call control
+    - **cc_prepaid_xmlrpc** - prepaid via external XMLRPC server
+    - **cc_registrar** - REGISTER caching and routing
+    - **cc_rest** - call control via REST API
+    - **cc_siprec** - SIPREC (RFC 7865/7866) call recording
+    - **cc_syslog_cdr** - call detail records via syslog
 
 ### Announcements (Prompts, Ringbacktones, Pre-call-prompts):
 
@@ -153,6 +169,15 @@ The following applications are shipped with SEMS :
 
 * **mwi** - Message Waiting Indication (MWI) support
 
+### Recording
+
+* **siprec_srs** - minimal SIPREC Session Recording Server (RFC 7865/7866).
+  Receives recording INVITEs from SIPREC clients (such as cc_siprec),
+  records both call legs to separate WAV files, and saves the SIPREC
+  metadata XML. Can run on the same SEMS instance as the SBC for
+  self-contained call recording. See also **cc_siprec** under the SBC
+  call_control modules.
+
 ### Media Processing
 
 * **mp3** - MP3 codec support and media processing

apps/CMakeLists.txt

@@ -35,6 +35,7 @@ if(RTMP_FOUND AND SPEEX_FOUND)
   add_subdirectory(rtmp)
 endif(RTMP_FOUND AND SPEEX_FOUND)
 add_subdirectory(sbc)
+add_subdirectory(siprec_srs)
 add_subdirectory(voicebox)
 add_subdirectory(voicemail)
 add_subdirectory(webconference)

apps/sbc/ExtendedCCInterface.h

@@ -7,6 +7,7 @@
 class SBCCallLeg;
 struct SBCCallProfile;
 class SimpleRelayDialog;
+class AmRtpPacket;
 
 struct InitialInviteHandlerParams
 {
@@ -76,6 +77,14 @@ class ExtendedCCInterface
     virtual void resumeAccepted(SBCCallLeg *call) { }
     virtual void resumeRejected(SBCCallLeg *call) { }
 
+    // RTP relay hooks (called from RTP receiver thread)
+
+    /** called after an RTP packet has been successfully relayed to the
+     *  B2B peer leg. Can be used for RTP stream forking (e.g. SIPREC).
+     *  Note: called from RTP receiver thread - must be non-blocking. */
+    virtual void onAfterRTPRelay(SBCCallLeg *call, AmRtpPacket* p,
+                                 sockaddr_storage* remote_addr) { }
+
     /** Possibility to influence messages relayed to the B2B peer leg.
       return value:
       - lower than 0 means error (returned upstream, the one

apps/sbc/SBC.cpp

@@ -412,6 +412,9 @@ void SBCFactory::onOoDRequest(const AmSipRequest& req)
   }
 
   if(req.max_forwards == 0) {
+    WARN("rejecting %s %s from %s:%d with 483 Too Many Hops (Max-Forwards=0)\n",
+         req.method.c_str(), req.r_uri.c_str(),
+         req.remote_ip.c_str(), req.remote_port);
     AmSipDialog::reply_error(req, 483, SIP_REPLY_TOO_MANY_HOPS);
     return;
   }

apps/sbc/SBCCallLeg.cpp

@@ -845,6 +845,8 @@ void SBCCallLeg::onInvite(const AmSipRequest& req)
   ctx.app_param = getHeader(req.hdrs, PARAM_HDR, true);
 
   if (req.max_forwards <= 0) {
+    WARN("rejecting INVITE %s from %s:%d with 483 Too Many Hops (Max-Forwards=%d)\n",
+         req.r_uri.c_str(), req.remote_ip.c_str(), req.remote_port, req.max_forwards);
     throw AmSession::Exception(483, SIP_REPLY_TOO_MANY_HOPS);
   }
 
@@ -1395,6 +1397,11 @@ void SBCCallLeg::onAfterRTPRelay(AmRtpPacket* p, sockaddr_storage* remote_addr)
       it != rtp_pegs.end(); ++it) {
     (*it)->inc(p->getBufferSize());
   }
+
+  for (vector<ExtendedCCInterface*>::iterator i = cc_ext.begin();
+       i != cc_ext.end(); ++i) {
+    (*i)->onAfterRTPRelay(this, p, remote_addr);
+  }
 }
 
 void SBCCallLeg::logCallStart(const AmSipReply& reply)

apps/sbc/call_control/CMakeLists.txt

@@ -9,6 +9,7 @@ add_subdirectory(prepaid)
 # ADD_SUBDIRECTORY (prepaid_xmlrpc)
 add_subdirectory(registrar)
 # ADD_SUBDIRECTORY (rest)
+add_subdirectory(siprec)
 add_subdirectory(syslog_cdr)
 # This one is actually a template and isn't intended for any real use.
 # ADD_SUBDIRECTORY (template)

apps/sbc/call_control/registrar/Registrar.cpp

@@ -57,7 +57,7 @@ class CCRegistrarFactory : public AmDynInvokeFactory
       if (CCRegistrar::instance()->onLoad())
 	return -1;
 
-      DBG("template call control loaded.\n");
+      DBG("registrar call control loaded.\n");
 
       return 0;
     }
@@ -228,10 +228,14 @@ void CCRegistrar::start(const string& cc_name, const string& ltag,
   if (NULL == req)
     REFUSE_WITH_404;
 
-  if ((req->method == "INVITE") && (retarget(req->r_uri, values, call_profile))){  
+  if ((req->method == "INVITE") && (retarget(req->r_uri, values, call_profile))){
+      INFO("Registrar: retargeted INVITE '%s' -> '%s'\n",
+           req->r_uri.c_str(), call_profile->ruri.c_str());
       return;
   }
 
+  INFO("Registrar: no registration found for '%s', rejecting with 404\n",
+       req->r_uri.c_str());
   REFUSE_WITH_404;
 }
 
@@ -256,16 +260,22 @@ void CCRegistrar::route(const string& cc_name,
 
 
   if (ood_req->method == "REGISTER"){
+    INFO("Registrar: REGISTER from '%s', Contact: '%s', source: %s:%d\n",
+         ood_req->from.c_str(), ood_req->contact.c_str(),
+         ood_req->remote_ip.c_str(), ood_req->remote_port);
+
     RegisterCacheCtx reg_cache_ctx;
 
     // reply 200 if possible, else continue
     bool replied = RegisterCache::instance()->saveSingleContact(reg_cache_ctx, *ood_req);
 
     if(replied) {
-      DBG("replied!");
+      INFO("Registrar: registration saved for '%s'\n", ood_req->from.c_str());
       res.push(AmArg());
       AmArg& res_cmd = res.back();
       res_cmd[SBC_CC_ACTION] = SBC_CC_DROP_ACTION;
+    } else {
+      WARN("Registrar: failed to save registration for '%s'\n", ood_req->from.c_str());
     }
   } else {
     if (retarget(ood_req->r_uri, values, call_profile)){