For some protocol's gso, like SCTP, it's using GSO_BY_FRAGS for
gso_size. When using UDP to encapsulate its packet, it will
return error in udp6_ufo_fragment() as skb->len < gso_size,
and it will never go to the gso tunnel processing.

So we should move this check after udp gso tunnel processing,
the same as udp4_ufo_fragment() does. While at it, also tidy
the variables up.

Signed-off-by: Xin Long <lucien....@gmail.com>
---
 net/ipv6/udp_offload.c | 154 ++++++++++++++++++++++++-------------------------
 1 file changed, 76 insertions(+), 78 deletions(-)

diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index 584157a..3c5ec8e 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -17,96 +17,94 @@
 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
                                         netdev_features_t features)
 {
+       u8 nexthdr, frag_hdr_sz = sizeof(struct frag_hdr);
+       unsigned int unfrag_ip6hlen, unfrag_len, mss;
        struct sk_buff *segs = ERR_PTR(-EINVAL);
-       unsigned int mss;
-       unsigned int unfrag_ip6hlen, unfrag_len;
-       struct frag_hdr *fptr;
+       const struct ipv6hdr *ipv6h;
        u8 *packet_start, *prevhdr;
-       u8 nexthdr;
-       u8 frag_hdr_sz = sizeof(struct frag_hdr);
+       struct frag_hdr *fptr;
+       int tnl_hlen, err;
+       struct udphdr *uh;
        __wsum csum;
-       int tnl_hlen;
-       int err;
 
-       mss = skb_shinfo(skb)->gso_size;
-       if (unlikely(skb->len <= mss))
+       if (skb->encapsulation &&
+           (skb_shinfo(skb)->gso_type &
+            (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM))) {
+               segs = skb_udp_tunnel_segment(skb, features, true);
                goto out;
+       }
 
-       if (skb->encapsulation && skb_shinfo(skb)->gso_type &
-           (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
-               segs = skb_udp_tunnel_segment(skb, features, true);
-       else {
-               const struct ipv6hdr *ipv6h;
-               struct udphdr *uh;
+       if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
+               goto out;
 
-               if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | 
SKB_GSO_UDP_L4)))
-                       goto out;
+       if (!pskb_may_pull(skb, sizeof(struct udphdr)))
+               goto out;
 
-               if (!pskb_may_pull(skb, sizeof(struct udphdr)))
-                       goto out;
+       if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
+               return __udp_gso_segment(skb, features);
 
-               if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
-                       return __udp_gso_segment(skb, features);
-
-               /* Do software UFO. Complete and fill in the UDP checksum as HW 
cannot
-                * do checksum of UDP packets sent as multiple IP fragments.
-                */
-
-               uh = udp_hdr(skb);
-               ipv6h = ipv6_hdr(skb);
-
-               uh->check = 0;
-               csum = skb_checksum(skb, 0, skb->len, 0);
-               uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
-                                         &ipv6h->daddr, csum);
-               if (uh->check == 0)
-                       uh->check = CSUM_MANGLED_0;
-
-               skb->ip_summed = CHECKSUM_UNNECESSARY;
-
-               /* If there is no outer header we can fake a checksum offload
-                * due to the fact that we have already done the checksum in
-                * software prior to segmenting the frame.
-                */
-               if (!skb->encap_hdr_csum)
-                       features |= NETIF_F_HW_CSUM;
-
-               /* Check if there is enough headroom to insert fragment header. 
*/
-               tnl_hlen = skb_tnl_header_len(skb);
-               if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
-                       if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
-                               goto out;
-               }
+       mss = skb_shinfo(skb)->gso_size;
+       if (unlikely(skb->len <= mss))
+               goto out;
 
-               /* Find the unfragmentable header and shift it left by 
frag_hdr_sz
-                * bytes to insert fragment header.
-                */
-               err = ip6_find_1stfragopt(skb, &prevhdr);
-               if (err < 0)
-                       return ERR_PTR(err);
-               unfrag_ip6hlen = err;
-               nexthdr = *prevhdr;
-               *prevhdr = NEXTHDR_FRAGMENT;
-               unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
-                            unfrag_ip6hlen + tnl_hlen;
-               packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
-               memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);
-
-               SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
-               skb->mac_header -= frag_hdr_sz;
-               skb->network_header -= frag_hdr_sz;
-
-               fptr = (struct frag_hdr *)(skb_network_header(skb) + 
unfrag_ip6hlen);
-               fptr->nexthdr = nexthdr;
-               fptr->reserved = 0;
-               fptr->identification = 
ipv6_proxy_select_ident(dev_net(skb->dev), skb);
-
-               /* Fragment the skb. ipv6 header and the remaining fields of the
-                * fragment header are updated in ipv6_gso_segment()
-                */
-               segs = skb_segment(skb, features);
+       /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
+        * do checksum of UDP packets sent as multiple IP fragments.
+        */
+
+       uh = udp_hdr(skb);
+       ipv6h = ipv6_hdr(skb);
+
+       uh->check = 0;
+       csum = skb_checksum(skb, 0, skb->len, 0);
+       uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
+                                &ipv6h->daddr, csum);
+       if (uh->check == 0)
+               uh->check = CSUM_MANGLED_0;
+
+       skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+       /* If there is no outer header we can fake a checksum offload
+        * due to the fact that we have already done the checksum in
+        * software prior to segmenting the frame.
+        */
+       if (!skb->encap_hdr_csum)
+               features |= NETIF_F_HW_CSUM;
+
+       /* Check if there is enough headroom to insert fragment header. */
+       tnl_hlen = skb_tnl_header_len(skb);
+       if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
+               if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
+                       goto out;
        }
 
+       /* Find the unfragmentable header and shift it left by frag_hdr_sz
+        * bytes to insert fragment header.
+        */
+       err = ip6_find_1stfragopt(skb, &prevhdr);
+       if (err < 0)
+               return ERR_PTR(err);
+       unfrag_ip6hlen = err;
+       nexthdr = *prevhdr;
+       *prevhdr = NEXTHDR_FRAGMENT;
+       unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
+                    unfrag_ip6hlen + tnl_hlen;
+       packet_start = (u8 *)skb->head + SKB_GSO_CB(skb)->mac_offset;
+       memmove(packet_start - frag_hdr_sz, packet_start, unfrag_len);
+
+       SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
+       skb->mac_header -= frag_hdr_sz;
+       skb->network_header -= frag_hdr_sz;
+
+       fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
+       fptr->nexthdr = nexthdr;
+       fptr->reserved = 0;
+       fptr->identification = ipv6_proxy_select_ident(dev_net(skb->dev), skb);
+
+       /* Fragment the skb. ipv6 header and the remaining fields of the
+        * fragment header are updated in ipv6_gso_segment()
+        */
+       segs = skb_segment(skb, features);
+
 out:
        return segs;
 }
-- 
2.1.0

Reply via email to