core: store pid per sip message

- when a sip message is received, store pid in sip_msg_t structure
- help identifying same sip msg across many processes

parser/msg_parser.h

@@ -260,6 +260,7 @@ typedef struct msg_body {
 /*! \brief The SIP message */
 typedef struct sip_msg {
 	unsigned int id;               /*!< message id, unique/process*/
+	int pid;                       /*!< process id */
 	snd_flags_t fwd_send_flags;    /*!< send flags for forwarding */
 	snd_flags_t rpl_send_flags;    /*!< send flags for replies */
 	struct msg_start first_line;   /*!< Message first line */

receive.c

@@ -135,6 +135,7 @@ int receive_msg(char* buf, unsigned int len, struct receive_info* rcv_info)
 	/* buf[len]=0; */ /* WARNING: zero term removed! */
 	msg->rcv=*rcv_info;
 	msg->id=msg_no;
+	msg->pid=my_pid();
 	msg->set_global_address=default_global_address;
 	msg->set_global_port=default_global_port;