QuteCom手记：exosip初始化和构建INVITE请求

@1、exosip初始化

qutecom/wifo/phapi/phapi.c

fun:owplInit()

Line:291

 

eXosip_set_user_agent(ua);设置SIP包头域User-Agent="qutecom/rev-335d495adbc1-trunk",即SIP客户端名称。

return_code = eXosip_init(0,0,udpPort,tcpPort,tlsPort);  if (return_code != 0){    owplLogError("eXosip_init failed");        return OWPL_RESULT_FAILURE;      }  //...      {           const char * ua=QUTECOM_UA;       eXosip_set_user_agent(ua);    }

 

@2、创建一个INVITE请求包

拨出电话需要构建一个INVITE发给服务器，服务器转发给另一个UAC。

 

调用关系：

PhApiWrapper::makeCall()

    ==>owplCallConnect()

        ==>phLinePlaceCall_withCa()

            ==>eXosip_build_initial_invite()

函数声明：

qutecom/wifo/eXosip/include/eXosip/eXosip.h

 

/** * Build a default INVITE message for a new call. *  * @param invite    Pointer for the SIP element to hold. * @param to        SIP url for callee. * @param from      SIP url for caller. * @param route     Route header for INVITE. (optionnal) * @param subject   Subject for the call. */int   eXosip_build_initial_invite(osip_message_t **invite, char *to, char *from, char *route, char *subject);

 

作用：

构建一个INVITE消息。

实现：

File: qutecom/wifo/eXosip/src/jrequest.c

 

/* this method can't be called unless the previous   INVITE transaction is over. */int eXosip_build_initial_invite(osip_message_t **invite, char *to, char *from,char *route, char *subject){  int i;  if (to!=NULL && *to=='/0')    return -1;  osip_clrspace(to);//清除空格  osip_clrspace(subject);  osip_clrspace(from);  osip_clrspace(route);  if (route!=NULL && *route=='/0')    route=NULL;  if (subject!=NULL && *subject=='/0')    subject=NULL;//构建INVITE包  i = generating_request_out_of_dialog(invite, "INVITE", to, from, route);  if (i!=0) return -1;#if 0  if (subject==NULL)  osip_message_set_subject(*invite, "New Call");  else  osip_message_set_subject(*invite, subject);#else  if (subject!=NULL)  osip_message_set_subject(*invite, subject);  //设置SIP头域的SUBJECT字段 //"Subject: Phone call"#endif  /* after this delay, we should send a CANCEL *///设置超时  owsip_message_set_expires(*invite, "120");  /* osip_message_set_organization(*invite, "Jack's Org"); */  return 0;}

 

函数generating_request_out_of_dialog调用generating_request_out_of_dialog2

 

generating_request_out_of_dialog2在qutecom/wifo/eXosip/src/jrequest.c实现

部分代码

static intgenerating_request_out_of_dialog2(osip_message_t **dest, char *method_name, char *to, char *from, char *proxy, int seqnum){  //...  i = osip_message_init(&request);//初始化  if (i!=0) return -1;  /* prepare the request-line */  osip_message_set_method(request, osip_strdup(method_name));  osip_message_set_version(request, osip_strdup("SIP/2.0"));//"INVITE sip:to@192.168.105.14 SIP/2.0"  osip_message_set_status_code(request, 0);  osip_message_set_reason_phrase(request, NULL);//  //...    i = osip_message_set_to(request, to);//"To: <sip:to@192.168.105.14>"  //...    osip_message_set_from(request, from);//    osip_from_set_tag(request->from, osip_from_tag_new_random());//"rom: <sip:from@192.168.105.5>;tag=29244"  //...  osip_call_id_set_number(callid, cidrand);//"Call-ID: 8103"  //...  osip_cseq_set_number(cseq, num);  osip_cseq_set_method(cseq, osip_strdup(method_name));          request->cseq = cseq; //"CSeq: 20 INVITE"  //...  osip_message_set_max_forwards(request, "70"); /* a UA should start a request with 70 */  //Max-Forwards: 70     //...  osip_message_set_via(request, tmp);//"Via: SIP/2.0/UDP 192.168.105.5:5060;rport;branch=z9hG4bK2195"  //...  osip_message_set_contact (request, contact) ;//"Contact: <sip:from@192.168.105.5:5060>"  //...  osip_message_set_user_agent(request, eXosip.user_agent);//"User-Agent: QuteCom2.2.1 (eXosip2/3.3.0)"  //...  //设定完头域后，INVITE消息应该长得像这样：  //INVITE sip:to@192.168.105.14 SIP/2.0     //Via: SIP/2.0/UDP 192.168.105.5:5060;rport;branch=z9hG4bK2195     //From: <sip:from@192.168.105.5>;tag=29244     //To: <sip:to@192.168.105.14>     //Call-ID: 8103     //CSeq: 20 INVITE     //Contact: <sip:from@192.168.105.5:5060>      //Max-Forwards: 70     //User-Agent: Linphone/3.2.1 (eXosip2/3.3.0)     //Subject: Phone call  //subject在eXosip_build_initial_invite中被设置。在本函数调用后随即调用}

 这个函数调用了oSip2库的一系列xxsetxx函数设置INVITE包的各个头域。

 头域的定义在《sip中文参考手册》P122 20 头域一节有完整说明

《sip中文参考手册》已经放在资源中。