net: add recursion limit to GRO

[cascardo/linux.git] / include / linux / netdevice.h

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 465e128..91ee364 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2169,7 +2169,10 @@ struct napi_gro_cb {
        /* Used to determine if flush_id can be ignored */
        u8      is_atomic:1;
 
-       /* 5 bit hole */
+       /* Number of gro_receive callbacks this packet already went through */
+       u8 recursion_counter:4;
+
+       /* 1 bit hole */
 
        /* used to support CHECKSUM_COMPLETE for tunneling protocols */
        __wsum  csum;
@@ -2180,6 +2183,40 @@ struct napi_gro_cb {
 
 #define NAPI_GRO_CB(skb) ((struct napi_gro_cb *)(skb)->cb)
 
+#define GRO_RECURSION_LIMIT 15
+static inline int gro_recursion_inc_test(struct sk_buff *skb)
+{
+       return ++NAPI_GRO_CB(skb)->recursion_counter == GRO_RECURSION_LIMIT;
+}
+
+typedef struct sk_buff **(*gro_receive_t)(struct sk_buff **, struct sk_buff *);
+static inline struct sk_buff **call_gro_receive(gro_receive_t cb,
+                                               struct sk_buff **head,
+                                               struct sk_buff *skb)
+{
+       if (unlikely(gro_recursion_inc_test(skb))) {
+               NAPI_GRO_CB(skb)->flush |= 1;
+               return NULL;
+       }
+
+       return cb(head, skb);
+}
+
+typedef struct sk_buff **(*gro_receive_sk_t)(struct sock *, struct sk_buff **,
+                                            struct sk_buff *);
+static inline struct sk_buff **call_gro_receive_sk(gro_receive_sk_t cb,
+                                                  struct sock *sk,
+                                                  struct sk_buff **head,
+                                                  struct sk_buff *skb)
+{
+       if (unlikely(gro_recursion_inc_test(skb))) {
+               NAPI_GRO_CB(skb)->flush |= 1;
+               return NULL;
+       }
+
+       return cb(sk, head, skb);
+}
+
 struct packet_type {
        __be16                  type;   /* This is really htons(ether_type). */
        struct net_device       *dev;   /* NULL is wildcarded here           */