UPF init fails to recover from af_xdp failure.

Pipeline initialization sequence fails to recover when upf-epc is
configured with non-DPDK settings. AF_XDP mode fails to transition
to AF_PACKET socket mode. A temporary fix is to disable AF_XDP mode.

Non-DPDK pipeline is also fixed in this PR.

Signed-off-by: Muhammad Asim Jamshed <muhammad.jamshed@intel.com>

conf/spgwu.bess

@@ -145,14 +145,14 @@ class Port:
         mode = self.detect_mode()
 
         if mode == 'linux':
-            try:
+            #try:
                 # Initialize kernel fastpath.
                 # AF_XDP requires that num_rx_qs == num_tx_qs
-                kwargs = {"vdev" : "net_af_xdp{},iface={},start_queue=0,queue_count={}"
-                          .format(idx, name, workers), "num_out_q": workers, "num_inc_q": workers}
-                self.init_fastpath(**kwargs)
-            except:
-                print('Failed to create AF_XDP socket for {}. Creating AF_PACKET socket instead.'.format(name))
+                #kwargs = {"vdev" : "net_af_xdp{},iface={},start_queue=0,queue_count={}"
+                #          .format(idx, name, workers), "num_out_q": workers, "num_inc_q": workers}
+                #self.init_fastpath(**kwargs)
+            #except:
+                #print('Failed to create AF_XDP socket for {}. Creating AF_PACKET socket instead.'.format(name))
                 kwargs = {"vdev" : "net_af_packet{},iface={},qpairs={}".format(idx, name, workers), "num_out_q": workers}
                 self.init_fastpath(**kwargs)
 
@@ -205,43 +205,6 @@ class Port:
                 # Direct control traffic from kernel to DPDK
                 spi -> self.fpo
 
-                # Direct fast path traffic to Frag module
-                merge = __bess_module__("{}Merge".format(name), 'Merge')
-
-                out = self.fpo
-
-                # Attach frag module (if enabled)
-                if ip_frag_with_eth_mtu is not None:
-                    frag = __bess_module__("{}IP4Frag".format(name), 'IPFrag', mtu=ip_frag_with_eth_mtu)
-                    frag:1 -> out
-                    frag:0 -> Sink()
-                    out = frag
-
-                # Attach telemeric module (if enabled)
-                if measure:
-                    m = Measure()
-                    m -> out
-                    out = m
-
-                # Attach nat module (if enabled)
-                if self.ext_addrs is not None:
-                    # Tokenize the string
-                    addrs = self.ext_addrs.split(' or ')
-                    # Make a list of ext_addr
-                    nat_list = list()
-                    for addr in addrs:
-                        nat_dict = dict()
-                        nat_dict['ext_addr'] = addr
-                        nat_list.append(nat_dict)
-
-                    # Create the NAT module
-                    self.nat = __bess_module__("{}NAT".format(conf[interface]["ifname"]), 'NAT', ext_addrs=nat_list)
-                    self.nat:1 -> out
-                    out = self.nat
-
-                # Attach Merge module to the 'outlist' of modules
-                merge -> out
-
                 tc = 'slow{}'.format(wid)
                 try:
                     bess.add_tc(tc, policy='round_robin', wid=wid)
@@ -262,6 +225,42 @@ class Port:
                 print('Mirror veth interface: {} misconfigured: {}'.format(name, e))
         else:
             raise Exception('Invalid mode selected.')
+        # Direct fast path traffic to Frag module
+        merge = __bess_module__("{}Merge".format(name), 'Merge')
+
+        out = self.fpo
+
+        # Attach frag module (if enabled)
+        if ip_frag_with_eth_mtu is not None:
+            frag = __bess_module__("{}IP4Frag".format(name), 'IPFrag', mtu=ip_frag_with_eth_mtu)
+            frag:1 -> out
+            frag:0 -> Sink()
+            out = frag
+
+        # Attach telemeric module (if enabled)
+        if measure:
+            m = Measure()
+            m -> out
+            out = m
+
+        # Attach nat module (if enabled)
+        if self.ext_addrs is not None:
+            # Tokenize the string
+            addrs = self.ext_addrs.split(' or ')
+            # Make a list of ext_addr
+            nat_list = list()
+            for addr in addrs:
+                nat_dict = dict()
+                nat_dict['ext_addr'] = addr
+                nat_list.append(nat_dict)
+
+                # Create the NAT module
+                self.nat = __bess_module__("{}NAT".format(conf[interface]["ifname"]), 'NAT', ext_addrs=nat_list)
+                self.nat:1 -> out
+                out = self.nat
+
+        # Attach Merge module to the 'outlist' of modules
+        merge -> out
 
 
 # ====================================================