fm10k: Modify tunnel length header check when offloading

The FM10000 host interface can only support up to 184 bytes when
performing tunnel offloads. Because of this, a check was added to
prevent the driver from attempting to feed a header to the hardware too
big for it to parse. Make this check a little more robust by calculating
the inner L4 header length based on whether it is TCP or UDP.

Cc: Joe Stringer <joestringer@nicira.com>
Signed-off-by: Matthew Vick <matthew.vick@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

2 files changed, 27 insertions, 9 deletions

diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
index 84ab9eea2768..a7d379802e7c 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
@@ -711,10 +711,6 @@ static struct ethhdr *fm10k_gre_is_nvgre(struct sk_buff *skb)
         if (nvgre_hdr->flags & FM10K_NVGRE_RESERVED0_FLAGS)
                 return NULL;
 
-        /* verify protocol is transparent Ethernet bridging */
-        if (nvgre_hdr->proto != htons(ETH_P_TEB))
-                return NULL;
-
         /* report start of ethernet header */
         if (nvgre_hdr->flags & NVGRE_TNI)
                 return (struct ethhdr *)(nvgre_hdr + 1);
@@ -724,13 +720,11 @@ static struct ethhdr *fm10k_gre_is_nvgre(struct sk_buff *skb)
 
 static __be16 fm10k_tx_encap_offload(struct sk_buff *skb)
 {
+        u8 l4_hdr = 0, inner_l4_hdr = 0, inner_l4_hlen;
         struct ethhdr *eth_hdr;
-        u8 l4_hdr = 0;
 
-/* fm10k supports 184 octets of outer+inner headers. Minus 20 for inner L4. */
-#define FM10K_MAX_ENCAP_TRANSPORT_OFFSET        164
-        if (skb_inner_transport_header(skb) - skb_mac_header(skb) >
-            FM10K_MAX_ENCAP_TRANSPORT_OFFSET)
+        if (skb->inner_protocol_type != ENCAP_TYPE_ETHER ||
+            skb->inner_protocol != htons(ETH_P_TEB))
                 return 0;
 
         switch (vlan_get_protocol(skb)) {
@@ -760,12 +754,33 @@ static __be16 fm10k_tx_encap_offload(struct sk_buff *skb)
 
         switch (eth_hdr->h_proto) {
         case htons(ETH_P_IP):
+                inner_l4_hdr = inner_ip_hdr(skb)->protocol;
+                break;
         case htons(ETH_P_IPV6):
+                inner_l4_hdr = inner_ipv6_hdr(skb)->nexthdr;
                 break;
         default:
                 return 0;
         }
 
+        switch (inner_l4_hdr) {
+        case IPPROTO_TCP:
+                inner_l4_hlen = inner_tcp_hdrlen(skb);
+                break;
+        case IPPROTO_UDP:
+                inner_l4_hlen = 8;
+                break;
+        default:
+                return 0;
+        }
+
+        /* The hardware allows tunnel offloads only if the combined inner and
+         * outer header is 184 bytes or less
+         */
+        if (skb_inner_transport_header(skb) + inner_l4_hlen -
+            skb_mac_header(skb) > FM10K_TUNNEL_HEADER_LENGTH)
+                return 0;
+
         return eth_hdr->h_proto;
 }
 
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_type.h b/drivers/net/ethernet/intel/fm10k/fm10k_type.h
index 7c6d9d5a8ae5..abb8a03824ac 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_type.h
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_type.h
@@ -356,6 +356,9 @@ struct fm10k_hw;
 #define FM10K_QUEUE_DISABLE_TIMEOUT             100
 #define FM10K_RESET_TIMEOUT                     150
 
+/* Maximum supported combined inner and outer header length for encapsulation */
+#define FM10K_TUNNEL_HEADER_LENGTH      184
+
 /* VF registers */
 #define FM10K_VFCTRL            0x00000
 #define FM10K_VFCTRL_RST                        0x00000008