ixgbe: Fix ATR so that it correctly handles IPv6 extension headers

The ATR code was assuming that it would be able to use tcp_hdr for
every TCP frame that came through.  However this isn't the case as it
is possible for a frame to arrive that is TCP but sent through something
like a raw socket.  As a result the driver was setting up bad filters in
which tcp_hdr was really pointing to the network header so the data was
all invalid.

In order to correct this I have added a bit of parsing logic that will
determine the TCP header location based off of the network header and
either the offset in the case of the IPv4 header, or a walk through the
IPv6 extension headers until it encounters the header that indicates
IPPROTO_TCP.  In addition I have added checks to verify that the lowest
protocol provided is recognized as IPv4 or IPv6 to help mitigate raw
sockets using ETH_P_ALL from having ATR applied to them.

Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index f67c9a6..ee81618 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -7558,8 +7558,10 @@ static void ixgbe_atr(struct ixgbe_ring *ring,
                struct ipv6hdr *ipv6;
        } hdr;
        struct tcphdr *th;
+       unsigned int hlen;
        struct sk_buff *skb;
        __be16 vlan_id;
+       int l4_proto;
 
        /* if ring doesn't have a interrupt vector, cannot perform ATR */
        if (!q_vector)
@@ -7571,10 +7573,14 @@ static void ixgbe_atr(struct ixgbe_ring *ring,
 
        ring->atr_count++;
 
+       /* currently only IPv4/IPv6 with TCP is supported */
+       if ((first->protocol != htons(ETH_P_IP)) &&
+           (first->protocol != htons(ETH_P_IPV6)))
+               return;
+
        /* snag network header to get L4 type and address */
        skb = first->skb;
        hdr.network = skb_network_header(skb);
-       th = tcp_hdr(skb);
 #ifdef CONFIG_IXGBE_VXLAN
        if (skb->encapsulation &&
            first->protocol == htons(ETH_P_IP) &&
@@ -7583,43 +7589,34 @@ static void ixgbe_atr(struct ixgbe_ring *ring,
 
                /* verify the port is recognized as VXLAN */
                if (adapter->vxlan_port &&
-                   udp_hdr(skb)->dest == adapter->vxlan_port) {
+                   udp_hdr(skb)->dest == adapter->vxlan_port)
                        hdr.network = skb_inner_network_header(skb);
-                       th = inner_tcp_hdr(skb);
-               }
        }
 #endif /* CONFIG_IXGBE_VXLAN */
 
        /* Currently only IPv4/IPv6 with TCP is supported */
        switch (hdr.ipv4->version) {
        case IPVERSION:
-               if (hdr.ipv4->protocol != IPPROTO_TCP)
-                       return;
+               /* access ihl as u8 to avoid unaligned access on ia64 */
+               hlen = (hdr.network[0] & 0x0F) << 2;
+               l4_proto = hdr.ipv4->protocol;
                break;
        case 6:
-               if (likely((unsigned char *)th - hdr.network ==
-                          sizeof(struct ipv6hdr))) {
-                       if (hdr.ipv6->nexthdr != IPPROTO_TCP)
-                               return;
-               } else {
-                       __be16 frag_off;
-                       u8 l4_hdr;
-
-                       ipv6_skip_exthdr(skb, hdr.network - skb->data +
-                                             sizeof(struct ipv6hdr),
-                                        &l4_hdr, &frag_off);
-                       if (unlikely(frag_off))
-                               return;
-                       if (l4_hdr != IPPROTO_TCP)
-                               return;
-               }
+               hlen = hdr.network - skb->data;
+               l4_proto = ipv6_find_hdr(skb, &hlen, IPPROTO_TCP, NULL, NULL);
+               hlen -= hdr.network - skb->data;
                break;
        default:
                return;
        }
 
-       /* skip this packet since it is invalid or the socket is closing */
-       if (!th || th->fin)
+       if (l4_proto != IPPROTO_TCP)
+               return;
+
+       th = (struct tcphdr *)(hdr.network + hlen);
+
+       /* skip this packet since the socket is closing */
+       if (th->fin)
                return;
 
        /* sample on all syn packets or once every atr sample count */