gro: Make GRO aware of lightweight tunnels.

[ Upstream commit ce87fc6ce3f9f4488546187e3757cf666d9d4a2a ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 7f00f24397700647d9e2be6ddd90482d65388971..7dc137fba5c15980feb9344ff56a9e9b8d534efd 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4145,6 +4145,7 @@ 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));
@@ -4342,10 +4343,12 @@ 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: