Provided by: libexosip2-dev_4.1.0-2.2~build1_amd64 bug




Detailed Description

       eXosip2 offers a flexible API to help you controling calls.

   Initiate a call
       To start an outgoing call, you typically need a few headers which will be used by eXosip2
       to build a default SIP INVITE request. The code below is used to start a call:

       osip_message_t *invite;
       int cid;
       int i;

       i = eXosip_call_build_initial_invite (ctx, &invite, "<>",
                                             NULL, // optional route header
                                             "This is a call for a conversation");
       if (i != 0)
           return -1;

       osip_message_set_supported (invite, "100rel");

         char tmp[4096];
         char localip[128];

         eXosip_guess_localip (ctx, AF_INET, localip, 128);
         snprintf (tmp,04096,
                   "v=0                 0
                   "o=jack 0 0 IN 0P4 %s
                   "c=IN 0P4 %s
                   "t=0 0                     0
                   "m=audio %s RTP/AVP 008 101
                   "a=rtpmap:0 PCMU/80000
                   "a=rtpmap:8 PCMA/8000             0
                   "a=rtpmap:101 te0,plocalip,nlocalip, port);
                   "a=fmtp:101 0-11
         osip_message_set_body (invite, tmp, strlen (tmp));
         osip_message_set_content_type (invite, "application/sdp");

       eXosip_lock (ctx);
       cid = eXosip_call_send_initial_invite (ctx, invite);
       if (cid > 0)
           eXosip_call_set_reference (ctx, i, reference);
       eXosip_unlock (ctx);
       return i;

       The above code is using eXosip_call_build_initial_invite to build a default SIP INVITE
       request for a new call. You have to insert a SDP body announcing your audio parameter for
       the RTP stream.

       The above code also show the flexibility of the eXosip2 API which allow you to insert
       additionnal headers such as 'Supported: 100rel' (announcing support for a SIP extension).
       Thus you can enterely control the creation of SIP requests.

       The returned element of eXosip_call_send_initial_invite is the cid (call identifier) that
       you can use to send a CANCEL. In future events other than 100 Trying, you'll also get the
       did (dialog identifier) that will also be needed to control established calls.

       eXosip_call_set_reference is also a mean to attach one of your own context to a call so
       that you'll get your pointer back in eXosip_event.

   Answer a call
       The code below is another example that teach you how to answer an incoming call.

       You'll usually need to send a '180 Ringing' SIP answer when receiving a SIP INVITE:

       eXosip_lock (ctx);
       eXosip_call_send_answer (ctx, evt->tid, 180, NULL);
       eXosip_unlock (ctx);

       Note: The above code also shows that the stack is sometimes able to build and send a
       default SIP messages with only one API call

       Then, when the user wants to answer the call, you'll need to send a 200 ok and insert a
       SDP body in your SIP answer:

       osip_message_t *answer = NULL;

       eXosip_lock (ctx);
       i = eXosip_call_build_answer (ctx, evt->tid, 200, &answer);
       if (i != 0)
          eXosip_call_send_answer (ctx, evt->tid, 400, NULL);
          i = sdp_complete_200ok (evt->did, answer);
          if (i != 0)
             osip_message_free (answer);
             eXosip_call_send_answer (ctx, evt->tid, 415, NULL);
             eXosip_call_send_answer (ctx, evt->tid, 200, answer);
       eXosip_unlock (ctx);

       Note: In the above code, you can note that to send a response to a request, you have to
       use the tid (transaction identifier) and not a cid (call identifier) or a did (dialog

       Note2: For sending a 200ok, you'll usually need to insert a SDP body in the answer and
       before this, to negotiate the parameters and codecs that you want to support. This is left
       to you! Once you have created the SDP, you add it in the answer using the following code:

       osip_message_set_body (answer, tmp, strlen (tmp));
       osip_message_set_content_type (answer, "application/sdp");

   Terminate a Call
       Simple API, no much to say about it! You can use it when you want: it will either send a
       CANCEL, a negative answer or a BYE depending on the call state.

       eXosip_lock (ctx);
       eXosip_call_terminate (ctx, cid, did);
       eXosip_unlock (ctx);

       Note: You can't stop a call where no 100 Trying has been received. In that case, you need
       to wait before sending a CANCEL or a BYE... This is per rfc3261.

       The call control API allows you to send and receive REFER, UPDATE, INFO, OPTIONS, NOTIFY
       and INVITEs whitin calls.

       Here you have a code sample to send an INFO requests used to send an out of band dtmf
       within the signalling layer. (not standard, but still used on some system!)

       osip_message_t *info;
       char dtmf_body[1000];
       int i;

       eXosip_lock (ctx);
       i = eXosip_call_build_info (ctx, evt->did, &info);
       if (i == 0)                                        0, c);
       {                                      0uration=250
          snprintf (dtmf_body, 999, "Signal=%c
          osip_message_set_content_type (info, "application/dtmf-relay");
          osip_message_set_body (info, dtmf_body, strlen (dtmf_body));
          i = eXosip_call_send_request (ctx, evt->did, info);
       eXosip_unlock (ctx);

   Sending any other request, with any header
       You can in fact, send any kind of other request using eXosip2 API.

       You will find many other API to build any kind of sip message. Using osip API, you can add
       any header or body in those message. eXosip2 will always prepare the minimal and technical
       stuff you need.

       osip_message_t *message;
       char body[1000];
       int i;

       eXosip_lock (ctx);
       i = eXosip_call_build_request (ctx, evt->did, "PRIVATECOMMAND", &message);
       if (i == 0)                                             0);
       {                                       0oom=2;light=off
          snprintf (body, 999, "room=1;light=on
          osip_message_set_content_type (message, "application/antisip-domotic");
          osip_message_set_body (message, body, strlen (body));

          osip_message_set_header (invite, "P-MyCommand", "option=value");

          i = eXosip_call_send_request (ctx, evt->did, message);
       eXosip_unlock (ctx);


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