Fixed ticket #111: workaround for forking dialog

git-svn-id: http://svn.pjsip.org/repos/pjproject/trunk@979 74dad513-b988-da41-8d7b-12977e46ad98

1 files changed, 28 insertions, 4 deletions

diff --git a/pjsip/src/pjsip/sip_dialog.c b/pjsip/src/pjsip/sip_dialog.c
index e22091d9..7efefc26 100644
--- a/pjsip/src/pjsip/sip_dialog.c
+++ b/pjsip/src/pjsip/sip_dialog.c
@@ -1518,11 +1518,26 @@ void pjsip_dlg_on_rx_response( pjsip_dialog *dlg, pjsip_rx_data *rdata )
 
     /* When we receive response that establishes dialog, update To tag, 
      * route set and dialog target.
+     *
+     * The second condition of the "if" is a workaround for forking.
+     * Originally, the dialog takes the first To tag seen and set it as
+     * the remote tag. If the tag in 2xx response is different than this
+     * tag, ACK will be sent with wrong To tag and incoming request with
+     * this tag will be rejected with 481.
+     *
+     * The workaround for this is to take the To tag received in the
+     * 2xx response and set it as remote tag.
      */
-    if (dlg->state == PJSIP_DIALOG_STATE_NULL && 
-	pjsip_method_creates_dialog(&rdata->msg_info.cseq->method) &&
-	(res_code > 100 && res_code < 300) &&
-	rdata->msg_info.to->tag.slen)
+    if ((dlg->state == PJSIP_DIALOG_STATE_NULL && 
+	 pjsip_method_creates_dialog(&rdata->msg_info.cseq->method) &&
+	 (res_code > 100 && res_code < 300) &&
+	 rdata->msg_info.to->tag.slen) 
+	 ||
+	(dlg->role==PJSIP_ROLE_UAC &&
+	 !dlg->uac_has_2xx &&
+	 res_code/100 == 2 &&
+	 pjsip_method_creates_dialog(&rdata->msg_info.cseq->method) &&
+	 pj_strcmp(&dlg->remote.info->tag, &rdata->msg_info.to->tag)))
     {
 	pjsip_hdr *hdr, *end_hdr;
 	pjsip_contact_hdr *contact;
@@ -1563,6 +1578,15 @@ void pjsip_dlg_on_rx_response( pjsip_dialog *dlg, pjsip_rx_data *rdata )
 	}
 
 	dlg->state = PJSIP_DIALOG_STATE_ESTABLISHED;
+
+	/* Prevent dialog from being updated just in case more 2xx
+	 * gets through this dialog (it shouldn't happen).
+	 */
+	if (dlg->role==PJSIP_ROLE_UAC && !dlg->uac_has_2xx && 
+	    res_code/100==2) 
+	{
+	    dlg->uac_has_2xx = PJ_TRUE;
+	}
     }
 
     /* Update remote target (again) when receiving 2xx response messages