res_pjsip_session: segfault on already disconnected session

On heavy loaded system the TCP/TLS incoming calls could be
disconnected by pjproject while these calls are being
processed by asterisk which could use the session's memory pools.
If the session in the disconnected state then the session memory
pools were already freed, so we get segfault.

This patch adds a lifetime control on an INVITE session to pjproject.
The lifetime of the session is manipulated by calling
pjsip_inv_add_ref/pjsip_inv_dec_ref.
This patch uses these functions to inform pjproject that the
session is in use.

This patch adds check if the session state is not disconnected
and also checks if the memory pool is not NULL.

This patch also places tasks 'session_end' and 'session_end_completion'
into session's serializer to avoid race condition.

ASTERISK-26291 #close

Change-Id: I4d28b1fb3b91f0492a911d110049d670fdc3c8d7

configure

@@ -935,6 +935,10 @@ PBX_POPT
 POPT_DIR
 POPT_INCLUDE
 POPT_LIB
+PBX_PJSIP_INV_SESSION_REF
+PJSIP_INV_SESSION_REF_DIR
+PJSIP_INV_SESSION_REF_INCLUDE
+PJSIP_INV_SESSION_REF_LIB
 PBX_PJSIP_EVSUB_GRP_LOCK
 PJSIP_EVSUB_GRP_LOCK_DIR
 PJSIP_EVSUB_GRP_LOCK_INCLUDE
@@ -11001,6 +11005,18 @@ PBX_PJSIP_EVSUB_GRP_LOCK=0
 
 
 
+PJSIP_INV_SESSION_REF_DESCRIP="PJSIP INVITE Session Reference Count support"
+PJSIP_INV_SESSION_REF_OPTION=pjsip
+PJSIP_INV_SESSION_REF_DIR=${PJPROJECT_DIR}
+
+PBX_PJSIP_INV_SESSION_REF=0
+
+
+
+
+
+
+
 
     POPT_DESCRIP="popt"
     POPT_OPTION="popt"
@@ -25269,6 +25285,9 @@ $as_echo "#define HAVE_PJSIP_TLS_TRANSPORT_PROTO 1" >>confdefs.h
 $as_echo "#define HAVE_PJSIP_EVSUB_GRP_LOCK 1" >>confdefs.h
 
 
+$as_echo "#define HAVE_PJSIP_INV_SESSION_REF 1" >>confdefs.h
+
+
    else
 
    if test "x${PBX_PJPROJECT}" != "x1" -a "${USE_PJPROJECT}" != "no"; then
@@ -26089,6 +26108,110 @@ _ACEOF
 fi
 
 
+
+if test "x${PBX_PJSIP_INV_SESSION_REF}" != "x1" -a "${USE_PJSIP_INV_SESSION_REF}" != "no"; then
+   pbxlibdir=""
+   # if --with-PJSIP_INV_SESSION_REF=DIR has been specified, use it.
+   if test "x${PJSIP_INV_SESSION_REF_DIR}" != "x"; then
+      if test -d ${PJSIP_INV_SESSION_REF_DIR}/lib; then
+         pbxlibdir="-L${PJSIP_INV_SESSION_REF_DIR}/lib"
+      else
+         pbxlibdir="-L${PJSIP_INV_SESSION_REF_DIR}"
+      fi
+   fi
+   pbxfuncname="pjsip_inv_add_ref"
+   if test "x${pbxfuncname}" = "x" ; then   # empty lib, assume only headers
+      AST_PJSIP_INV_SESSION_REF_FOUND=yes
+   else
+      ast_ext_lib_check_save_CFLAGS="${CFLAGS}"
+      CFLAGS="${CFLAGS} $PJPROJECT_CFLAGS"
+      as_ac_Lib=`$as_echo "ac_cv_lib_pjsip_${pbxfuncname}" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ${pbxfuncname} in -lpjsip" >&5
+$as_echo_n "checking for ${pbxfuncname} in -lpjsip... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lpjsip ${pbxlibdir} $PJPROJECT_LIB $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char ${pbxfuncname} ();
+int
+main ()
+{
+return ${pbxfuncname} ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  eval "$as_ac_Lib=yes"
+else
+  eval "$as_ac_Lib=no"
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+eval ac_res=\$$as_ac_Lib
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
+  AST_PJSIP_INV_SESSION_REF_FOUND=yes
+else
+  AST_PJSIP_INV_SESSION_REF_FOUND=no
+fi
+
+      CFLAGS="${ast_ext_lib_check_save_CFLAGS}"
+   fi
+
+   # now check for the header.
+   if test "${AST_PJSIP_INV_SESSION_REF_FOUND}" = "yes"; then
+      PJSIP_INV_SESSION_REF_LIB="${pbxlibdir} -lpjsip $PJPROJECT_LIB"
+      # if --with-PJSIP_INV_SESSION_REF=DIR has been specified, use it.
+      if test "x${PJSIP_INV_SESSION_REF_DIR}" != "x"; then
+         PJSIP_INV_SESSION_REF_INCLUDE="-I${PJSIP_INV_SESSION_REF_DIR}/include"
+      fi
+      PJSIP_INV_SESSION_REF_INCLUDE="${PJSIP_INV_SESSION_REF_INCLUDE} $PJPROJECT_CFLAGS"
+      if test "xpjsip.h" = "x" ; then	# no header, assume found
+         PJSIP_INV_SESSION_REF_HEADER_FOUND="1"
+      else				# check for the header
+         ast_ext_lib_check_saved_CPPFLAGS="${CPPFLAGS}"
+         CPPFLAGS="${CPPFLAGS} ${PJSIP_INV_SESSION_REF_INCLUDE}"
+         ac_fn_c_check_header_mongrel "$LINENO" "pjsip.h" "ac_cv_header_pjsip_h" "$ac_includes_default"
+if test "x$ac_cv_header_pjsip_h" = xyes; then :
+  PJSIP_INV_SESSION_REF_HEADER_FOUND=1
+else
+  PJSIP_INV_SESSION_REF_HEADER_FOUND=0
+fi
+
+
+         CPPFLAGS="${ast_ext_lib_check_saved_CPPFLAGS}"
+      fi
+      if test "x${PJSIP_INV_SESSION_REF_HEADER_FOUND}" = "x0" ; then
+         PJSIP_INV_SESSION_REF_LIB=""
+         PJSIP_INV_SESSION_REF_INCLUDE=""
+      else
+         if test "x${pbxfuncname}" = "x" ; then		# only checking headers -> no library
+            PJSIP_INV_SESSION_REF_LIB=""
+         fi
+         PBX_PJSIP_INV_SESSION_REF=1
+         cat >>confdefs.h <<_ACEOF
+#define HAVE_PJSIP_INV_SESSION_REF 1
+_ACEOF
+
+      fi
+   fi
+fi
+
+
    fi
 fi