gro: Make GRO aware of lightweight tunnels.

GRO is currently not aware of tunnel metadata generated by lightweight
tunnels and stored in the dst. This leads to two possible problems:
 * Incorrectly merging two frames that have different metadata.
 * Leaking of allocated metadata from merged frames.

This avoids those problems by comparing the tunnel information before
merging, similar to how we handle other metadata (such as vlan tags),
and releasing any state when we are done.

Reported-by: John <john.phillips5@hpe.com>
Fixes: 2e15ea39 ("ip_gre: Add support to collect tunnel metadata.")
Signed-off-by: Jesse Gross <jesse@kernel.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h
index 6816f0fa5693dc275e1e4997375f29b5d99f7b64..30a56ab2ccfb05d7bc9a527ebdc09da19b3d5f7b 100644 (file)
--- a/include/net/dst_metadata.h
+++ b/include/net/dst_metadata.h
@@ -44,6 +44,24 @@ static inline bool skb_valid_dst(const struct sk_buff *skb)
        return dst && !(dst->flags & DST_METADATA);
 }
 
+static inline int skb_metadata_dst_cmp(const struct sk_buff *skb_a,
+                                      const struct sk_buff *skb_b)
+{
+       const struct metadata_dst *a, *b;
+
+       if (!(skb_a->_skb_refdst | skb_b->_skb_refdst))
+               return 0;
+
+       a = (const struct metadata_dst *) skb_dst(skb_a);
+       b = (const struct metadata_dst *) skb_dst(skb_b);
+
+       if (!a != !b || a->u.tun_info.options_len != b->u.tun_info.options_len)
+               return 1;
+
+       return memcmp(&a->u.tun_info, &b->u.tun_info,
+                     sizeof(a->u.tun_info) + a->u.tun_info.options_len);
+}
+
 struct metadata_dst *metadata_dst_alloc(u8 optslen, gfp_t flags);
 struct metadata_dst __percpu *metadata_dst_alloc_percpu(u8 optslen, gfp_t flags);
 

diff --git a/net/core/dev.c b/net/core/dev.c
index cc9e3652cf93a6306e6f614f966e0fe7cf17a10e..8cba3d852f251c503b193823b71b27aaef3fb3ae 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4351,6 +4351,7 @@ static void gro_list_prepare(struct napi_struct *napi, struct sk_buff *skb)
 
                diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev;
                diffs |= p->vlan_tci ^ skb->vlan_tci;
+               diffs |= skb_metadata_dst_cmp(p, skb);
                if (maclen == ETH_HLEN)
                        diffs |= compare_ether_header(skb_mac_header(p),
                                                      skb_mac_header(skb));
@@ -4548,10 +4549,12 @@ static gro_result_t napi_skb_finish(gro_result_t ret, struct sk_buff *skb)
                break;
 
        case GRO_MERGED_FREE:
-               if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD)
+               if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD) {
+                       skb_dst_drop(skb);
                        kmem_cache_free(skbuff_head_cache, skb);
-               else
+               } else {
                        __kfree_skb(skb);
+               }
                break;
 
        case GRO_HELD: