From f5462369f3ad22c9d19f54832faa2b6e61449f66 Mon Sep 17 00:00:00 2001
From: Mohsin Kazmi <sykazmi@cisco.com>
Date: Tue, 23 Feb 2021 15:55:04 +0100
Subject: devices: add support for pseudo header checksum

Type: improvement

Linux uses pseudo header checksum when checksum of l4 is offloaded.
This patch adds similar support in virtual interfaces.

Change-Id: I6a94d1104e59356f95057e7c122e3be9cd8659a3
Signed-off-by: Aloys Augustin <aloaugus@cisco.com>
Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
---
 src/vnet/devices/virtio/device.c | 42 +++++++++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 9 deletions(-)

(limited to 'src/vnet/devices/virtio/device.c')

diff --git a/src/vnet/devices/virtio/device.c b/src/vnet/devices/virtio/device.c
index 6c2fe34abf0..ac9be6b02ae 100644
--- a/src/vnet/devices/virtio/device.c
+++ b/src/vnet/devices/virtio/device.c
@@ -27,6 +27,7 @@
 #include <vnet/gso/hdr_offset_parser.h>
 #include <vnet/ip/ip4_packet.h>
 #include <vnet/ip/ip6_packet.h>
+#include <vnet/ip/ip_psh_cksum.h>
 #include <vnet/tcp/tcp_packet.h>
 #include <vnet/udp/udp_packet.h>
 #include <vnet/devices/virtio/virtio.h>
@@ -296,37 +297,60 @@ set_checksum_offsets (vlib_buffer_t *b, virtio_net_hdr_v1_t *hdr,
 					 0 /* ip6 */ );
       hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
       hdr->csum_start = gho.l4_hdr_offset;	// 0x22;
+
+      /*
+       * virtio devices do not support IP4 checksum offload. So driver takes
+       * care of it while doing tx.
+       */
+      ip4 = (ip4_header_t *) (vlib_buffer_get_current (b) + gho.l3_hdr_offset);
+      if (oflags & VNET_BUFFER_OFFLOAD_F_IP_CKSUM)
+	ip4->checksum = ip4_header_checksum (ip4);
+
+      /*
+       * virtio devices assume the l4 header is set to the checksum of the
+       * l3 pseudo-header, so we compute it before tx-ing
+       */
       if (oflags & VNET_BUFFER_OFFLOAD_F_TCP_CKSUM)
 	{
+	  tcp_header_t *tcp =
+	    (tcp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+	  tcp->checksum = ip4_pseudo_header_cksum (ip4);
 	  hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);
 	}
       else if (oflags & VNET_BUFFER_OFFLOAD_F_UDP_CKSUM)
 	{
+	  udp_header_t *udp =
+	    (udp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+	  udp->checksum = ip4_pseudo_header_cksum (ip4);
 	  hdr->csum_offset = STRUCT_OFFSET_OF (udp_header_t, checksum);
 	}
-
-      /*
-       * virtio devices do not support IP4 checksum offload. So driver takes care
-       * of it while doing tx.
-       */
-      ip4 =
-	(ip4_header_t *) (vlib_buffer_get_current (b) + gho.l3_hdr_offset);
-      if (oflags & VNET_BUFFER_OFFLOAD_F_IP_CKSUM)
-	ip4->checksum = ip4_header_checksum (ip4);
     }
   else if (b->flags & VNET_BUFFER_F_IS_IP6)
     {
+      ip6_header_t *ip6;
       generic_header_offset_t gho = { 0 };
       vnet_generic_header_offset_parser (b, &gho, is_l2, 0 /* ip4 */ ,
 					 1 /* ip6 */ );
       hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
       hdr->csum_start = gho.l4_hdr_offset;	// 0x36;
+      ip6 = (ip6_header_t *) (vlib_buffer_get_current (b) + gho.l3_hdr_offset);
+
+      /*
+       * virtio devices assume the l4 header is set to the checksum of the
+       * l3 pseudo-header, so we compute it before tx-ing
+       */
       if (oflags & VNET_BUFFER_OFFLOAD_F_TCP_CKSUM)
 	{
+	  tcp_header_t *tcp =
+	    (tcp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+	  tcp->checksum = ip6_pseudo_header_cksum (ip6);
 	  hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);
 	}
       else if (oflags & VNET_BUFFER_OFFLOAD_F_UDP_CKSUM)
 	{
+	  udp_header_t *udp =
+	    (udp_header_t *) (vlib_buffer_get_current (b) + gho.l4_hdr_offset);
+	  udp->checksum = ip6_pseudo_header_cksum (ip6);
 	  hdr->csum_offset = STRUCT_OFFSET_OF (udp_header_t, checksum);
 	}
     }
-- 
cgit 1.2.3-korg