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 <[email protected]> Fixes: 2e15ea3 ("ip_gre: Add support to collect tunnel metadata.") Signed-off-by: Jesse Gross <[email protected]> Acked-by: Eric Dumazet <[email protected]> Acked-by: Thomas Graf <[email protected]> Signed-off-by: David S. Miller <[email protected]>
akeromi · Jan 21, 2016 · ce87fc6 · ce87fc6
1 parent 5f2f3ca
commit ce87fc6
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Showing 2 changed files with 23 additions and 2 deletions.
diff --git 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
@@ -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: