Make ip csum configurable in vlib buffer functions

Also fixes csum computation for lisp control plane 4o6 encapsulated control
messages.

Change-Id: I991e0b5c0d16dc51e0b5bdc79e1d752270b34765
Signed-off-by: Florin Coras <fcoras@cisco.com>

8 files changed, 28 insertions, 24 deletions

diff --git a/src/vnet/interface_output.c b/src/vnet/interface_output.c
index c95f08b1..06f1c7dd 100644
--- a/src/vnet/interface_output.c
+++ b/src/vnet/interface_output.c
@@ -188,7 +188,6 @@ calc_checksums (vlib_main_t * vm, vlib_buffer_t * b)
   if (is_ip6)
     {
       int bogus;
-      ASSERT (b->flags & VNET_BUFFER_F_OFFLOAD_IP_CKSUM);
       if (b->flags & VNET_BUFFER_F_OFFLOAD_TCP_CKSUM)
 	th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ip6, &bogus);
       if (b->flags & VNET_BUFFER_F_OFFLOAD_UDP_CKSUM)
diff --git a/src/vnet/ip/ip4.h b/src/vnet/ip/ip4.h
index 872b516c..8f9a8e27 100644
--- a/src/vnet/ip/ip4.h
+++ b/src/vnet/ip/ip4.h
@@ -329,7 +329,8 @@ u32 ip4_tcp_udp_validate_checksum (vlib_main_t * vm, vlib_buffer_t * p0);
  */
 always_inline void *
 vlib_buffer_push_ip4 (vlib_main_t * vm, vlib_buffer_t * b,
-		      ip4_address_t * src, ip4_address_t * dst, int proto)
+		      ip4_address_t * src, ip4_address_t * dst, int proto,
+		      u8 csum_offload)
 {
   ip4_header_t *ih;
 
@@ -348,7 +349,7 @@ vlib_buffer_push_ip4 (vlib_main_t * vm, vlib_buffer_t * b,
   ih->dst_address.as_u32 = dst->as_u32;
 
   /* Offload ip4 header checksum generation */
-  if (1)
+  if (csum_offload)
     {
       ih->checksum = 0;
       b->flags |= VNET_BUFFER_F_OFFLOAD_IP_CKSUM | VNET_BUFFER_F_IS_IP4;
diff --git a/src/vnet/ip/ip6.h b/src/vnet/ip/ip6.h
index cf52994e..fa922725 100644
--- a/src/vnet/ip/ip6.h
+++ b/src/vnet/ip/ip6.h
@@ -576,6 +576,7 @@ vlib_buffer_push_ip6 (vlib_main_t * vm, vlib_buffer_t * b,
 	       sizeof (ip6h->src_address));
   clib_memcpy (ip6h->dst_address.as_u8, dst->as_u8,
 	       sizeof (ip6h->src_address));
+  b->flags |= VNET_BUFFER_F_IS_IP6;
 
   return ip6h;
 }
diff --git a/src/vnet/lisp-cp/control.c b/src/vnet/lisp-cp/control.c
index d8a1372d..fc860e14 100644
--- a/src/vnet/lisp-cp/control.c
+++ b/src/vnet/lisp-cp/control.c
@@ -2257,7 +2257,7 @@ build_map_request (lisp_cp_main_t * lcm, gid_address_t * deid,
 
   /* push outer ip header */
   pkt_push_udp_and_ip (vm, b, LISP_CONTROL_PORT, LISP_CONTROL_PORT, sloc,
-		       rloc);
+		       rloc, 1);
 
   bi_res[0] = bi;
 
@@ -2283,6 +2283,7 @@ build_encapsulated_map_request (lisp_cp_main_t * lcm,
     }
 
   b = vlib_get_buffer (vm, bi);
+  b->flags = 0;
 
   /* leave some space for the encap headers */
   vlib_buffer_make_headroom (b, MAX_LISP_MSG_ENCAP_LEN);
@@ -2311,7 +2312,7 @@ build_encapsulated_map_request (lisp_cp_main_t * lcm,
 
   /* push outer ip header */
   pkt_push_udp_and_ip (vm, b, LISP_CONTROL_PORT, LISP_CONTROL_PORT, sloc,
-		       mr_ip);
+		       mr_ip, 1);
 
   bi_res[0] = bi;
 
@@ -2466,7 +2467,7 @@ build_map_register (lisp_cp_main_t * lcm, ip_address_t * sloc,
 
   /* push outer ip header */
   pkt_push_udp_and_ip (vm, b, LISP_CONTROL_PORT, LISP_CONTROL_PORT, sloc,
-		       ms_ip);
+		       ms_ip, 1);
 
   bi_res[0] = bi;
   return b;
@@ -3650,7 +3651,7 @@ build_map_reply (lisp_cp_main_t * lcm, ip_address_t * sloc,
   lisp_msg_put_map_reply (b, records, nonce, probe_bit);
 
   /* push outer ip header */
-  pkt_push_udp_and_ip (vm, b, LISP_CONTROL_PORT, dst_port, sloc, dst);
+  pkt_push_udp_and_ip (vm, b, LISP_CONTROL_PORT, dst_port, sloc, dst, 1);
 
   bi_res[0] = bi;
   return b;
diff --git a/src/vnet/lisp-cp/lisp_msg_serdes.c b/src/vnet/lisp-cp/lisp_msg_serdes.c
index 6c0a7219..aee4f25e 100644
--- a/src/vnet/lisp-cp/lisp_msg_serdes.c
+++ b/src/vnet/lisp-cp/lisp_msg_serdes.c
@@ -229,7 +229,7 @@ lisp_msg_push_ecm (vlib_main_t * vm, vlib_buffer_t * b, int lp, int rp,
     }
 
   /* Push inner ip and udp */
-  pkt_push_udp_and_ip (vm, b, lp, rp, src_ip, dst_ip);
+  pkt_push_udp_and_ip (vm, b, lp, rp, src_ip, dst_ip, 0);
 
   /* Push lisp ecm hdr */
   h = pkt_push_ecm_hdr (b);
diff --git a/src/vnet/lisp-cp/packets.c b/src/vnet/lisp-cp/packets.c
index a3d6f1cd..25086b8e 100644
--- a/src/vnet/lisp-cp/packets.c
+++ b/src/vnet/lisp-cp/packets.c
@@ -143,7 +143,7 @@ pkt_push_udp (vlib_main_t * vm, vlib_buffer_t * b, u16 sp, u16 dp)
 
 void *
 pkt_push_ip (vlib_main_t * vm, vlib_buffer_t * b, ip_address_t * src,
-	     ip_address_t * dst, u32 proto)
+	     ip_address_t * dst, u32 proto, u8 csum_offload)
 {
   if (ip_addr_version (src) != ip_addr_version (dst))
     {
@@ -156,7 +156,7 @@ pkt_push_ip (vlib_main_t * vm, vlib_buffer_t * b, ip_address_t * src,
     {
     case IP4:
       return vlib_buffer_push_ip4 (vm, b, &ip_addr_v4 (src),
-				   &ip_addr_v4 (dst), proto);
+				   &ip_addr_v4 (dst), proto, csum_offload);
       break;
     case IP6:
       return vlib_buffer_push_ip6 (vm, b, &ip_addr_v6 (src),
@@ -167,11 +167,9 @@ pkt_push_ip (vlib_main_t * vm, vlib_buffer_t * b, ip_address_t * src,
   return 0;
 }
 
-#define UDP_CHECKSUM_OFFLOAD 1
-
 void *
 pkt_push_udp_and_ip (vlib_main_t * vm, vlib_buffer_t * b, u16 sp, u16 dp,
-		     ip_address_t * sip, ip_address_t * dip)
+		     ip_address_t * sip, ip_address_t * dip, u8 csum_offload)
 {
   u16 udpsum;
   udp_header_t *uh;
@@ -179,10 +177,9 @@ pkt_push_udp_and_ip (vlib_main_t * vm, vlib_buffer_t * b, u16 sp, u16 dp,
 
   uh = pkt_push_udp (vm, b, sp, dp);
 
-  ih = pkt_push_ip (vm, b, sip, dip, IP_PROTOCOL_UDP);
-
-  if (UDP_CHECKSUM_OFFLOAD)
+  if (csum_offload)
     {
+      ih = pkt_push_ip (vm, b, sip, dip, IP_PROTOCOL_UDP, 1);
       b->flags |= VNET_BUFFER_F_OFFLOAD_UDP_CKSUM;
       vnet_buffer (b)->l3_hdr_offset = (u8 *) ih - b->data;
       vnet_buffer (b)->l4_hdr_offset = (u8 *) uh - b->data;
@@ -190,6 +187,7 @@ pkt_push_udp_and_ip (vlib_main_t * vm, vlib_buffer_t * b, u16 sp, u16 dp,
     }
   else
     {
+      ih = pkt_push_ip (vm, b, sip, dip, IP_PROTOCOL_UDP, 0);
       udpsum = udp_checksum (uh, clib_net_to_host_u16 (uh->length), ih,
 			     ip_addr_version (sip));
       if (udpsum == (u16) ~ 0)
@@ -197,6 +195,8 @@ pkt_push_udp_and_ip (vlib_main_t * vm, vlib_buffer_t * b, u16 sp, u16 dp,
 	  clib_warning ("Failed UDP checksum! Discarding");
 	  return 0;
 	}
+      /* clear flags used for csum since we're not offloading */
+      b->flags &= ~(VNET_BUFFER_F_IS_IP4 | VNET_BUFFER_F_IS_IP6);
       uh->checksum = udpsum;
     }
   return ih;
diff --git a/src/vnet/lisp-cp/packets.h b/src/vnet/lisp-cp/packets.h
index f6da3bf4..eb9871bf 100644
--- a/src/vnet/lisp-cp/packets.h
+++ b/src/vnet/lisp-cp/packets.h
@@ -19,10 +19,11 @@
 #define IP_DF 0x4000		/* don't fragment */
 
 void *pkt_push_ip (vlib_main_t * vm, vlib_buffer_t * b, ip_address_t * src,
-		   ip_address_t * dst, u32 proto);
+		   ip_address_t * dst, u32 proto, u8 csum_offload);
 
 void *pkt_push_udp_and_ip (vlib_main_t * vm, vlib_buffer_t * b, u16 sp,
-			   u16 dp, ip_address_t * sip, ip_address_t * dip);
+			   u16 dp, ip_address_t * sip, ip_address_t * dip,
+			   u8 cksum_offload);
 
 void *pkt_push_ecm_hdr (vlib_buffer_t * b);
 
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 1ecb6ce6..ad13493a 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -675,7 +675,7 @@ tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0,
   if (is_ip4)
     {
       ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40,
-				  IP_PROTOCOL_TCP);
+				  IP_PROTOCOL_TCP, 1);
       th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4);
     }
   else
@@ -747,7 +747,7 @@ tcp_send_reset (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4)
     {
       ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40);
       ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address,
-				  &pkt_ih4->src_address, IP_PROTOCOL_TCP);
+				  &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1);
       th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4);
     }
   else
@@ -776,7 +776,7 @@ tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b)
     {
       ip4_header_t *ih;
       ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4,
-				 &tc->c_rmt_ip4, IP_PROTOCOL_TCP);
+				 &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1);
       th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih);
     }
   else
@@ -1508,9 +1508,10 @@ tcp46_output_inline (vlib_main_t * vm,
 	    {
 	      ip4_header_t *ih0;
 	      ih0 = vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4,
-					  &tc0->c_rmt_ip4, IP_PROTOCOL_TCP);
-	      b0->flags |= VNET_BUFFER_F_IS_IP4 |
-		VNET_BUFFER_F_OFFLOAD_IP_CKSUM |
+					  &tc0->c_rmt_ip4, IP_PROTOCOL_TCP,
+					  1);
+	      b0->flags |=
+		VNET_BUFFER_F_IS_IP4 | VNET_BUFFER_F_OFFLOAD_IP_CKSUM |
 		VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
 	      vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data;
 	      vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data;