virtio: fix checksum offload support

Checksum offload and GSO are independent. We must support checksum
offload if it has been negotiated, independently of GSO.

Ticket: VPPSUPP-47
Type: fix

Change-Id: I8cb6dd58b61714ebb2726eb4aab0d74d49fdab99
Signed-off-by: Benoît Ganne <bganne@cisco.com>

diff --git a/src/vnet/devices/virtio/node.c b/src/vnet/devices/virtio/node.c
index e9c72eb..ba17075 100644 (file)
--- a/src/vnet/devices/virtio/node.c
+++ b/src/vnet/devices/virtio/node.c
@@ -142,10 +142,12 @@ more:
 }
 
 static_always_inline void
-fill_gso_buffer_flags (vlib_buffer_t * b0, struct virtio_net_hdr_v1 *hdr)
+virtio_needs_csum (vlib_buffer_t * b0, struct virtio_net_hdr_v1 *hdr,
+                  u8 * l4_proto, u8 * l4_hdr_sz)
 {
-  u8 l4_proto = 0;
-  u8 l4_hdr_sz = 0;
+  *l4_proto = 0;
+  *l4_hdr_sz = 0;
+
   if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM)
 
     {
@@ -175,7 +177,7 @@ fill_gso_buffer_flags (vlib_buffer_t * b0, struct virtio_net_hdr_v1 *hdr)
          ip4_header_t *ip4 =
            (ip4_header_t *) (vlib_buffer_get_current (b0) + l2hdr_sz);
          vnet_buffer (b0)->l4_hdr_offset = l2hdr_sz + ip4_header_bytes (ip4);
-         l4_proto = ip4->protocol;
+         *l4_proto = ip4->protocol;
          b0->flags |=
            (VNET_BUFFER_F_IS_IP4 | VNET_BUFFER_F_OFFLOAD_IP_CKSUM);
          b0->flags |=
@@ -189,32 +191,38 @@ fill_gso_buffer_flags (vlib_buffer_t * b0, struct virtio_net_hdr_v1 *hdr)
            (ip6_header_t *) (vlib_buffer_get_current (b0) + l2hdr_sz);
          vnet_buffer (b0)->l4_hdr_offset = l2hdr_sz + sizeof (ip6_header_t);
          /* FIXME IPv6 EH traversal */
-         l4_proto = ip6->protocol;
+         *l4_proto = ip6->protocol;
          b0->flags |= (VNET_BUFFER_F_IS_IP6 |
                        VNET_BUFFER_F_L2_HDR_OFFSET_VALID
                        | VNET_BUFFER_F_L3_HDR_OFFSET_VALID |
                        VNET_BUFFER_F_L4_HDR_OFFSET_VALID);
        }
-      if (l4_proto == IP_PROTOCOL_TCP)
+      if (*l4_proto == IP_PROTOCOL_TCP)
        {
          b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
          tcp_header_t *tcp = (tcp_header_t *) (vlib_buffer_get_current (b0) +
                                                vnet_buffer
                                                (b0)->l4_hdr_offset);
-         l4_hdr_sz = tcp_header_bytes (tcp);
+         *l4_hdr_sz = tcp_header_bytes (tcp);
          tcp->checksum = 0;
        }
-      else if (l4_proto == IP_PROTOCOL_UDP)
+      else if (*l4_proto == IP_PROTOCOL_UDP)
        {
          b0->flags |= VNET_BUFFER_F_OFFLOAD_UDP_CKSUM;
          udp_header_t *udp = (udp_header_t *) (vlib_buffer_get_current (b0) +
                                                vnet_buffer
                                                (b0)->l4_hdr_offset);
-         l4_hdr_sz = sizeof (*udp);
+         *l4_hdr_sz = sizeof (*udp);
          udp->checksum = 0;
        }
     }
 
+}
+
+static_always_inline void
+fill_gso_buffer_flags (vlib_buffer_t * b0, struct virtio_net_hdr_v1 *hdr,
+                      u8 l4_proto, u8 l4_hdr_sz)
+{
   if (hdr->gso_type == VIRTIO_NET_HDR_GSO_TCPV4)
     {
       ASSERT (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM);
@@ -264,6 +272,7 @@ virtio_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 
       while (n_left && n_left_to_next)
        {
+         u8 l4_proto, l4_hdr_sz;
          u16 num_buffers = 1;
          struct vring_used_elem *e = &vring->used->ring[last & mask];
          struct virtio_net_hdr_v1 *hdr;
@@ -280,8 +289,10 @@ virtio_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
          b0->total_length_not_including_first_buffer = 0;
          b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 
+         virtio_needs_csum (b0, hdr, &l4_proto, &l4_hdr_sz);
+
          if (gso_enabled)
-           fill_gso_buffer_flags (b0, hdr);
+           fill_gso_buffer_flags (b0, hdr, l4_proto, l4_hdr_sz);
 
          vnet_buffer (b0)->sw_if_index[VLIB_RX] = vif->sw_if_index;
          vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;