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authorHannes Frederic Sowa <hannes@stressinduktion.org>2013-03-15 15:32:30 +0400
committerDavid S. Miller <davem@davemloft.net>2013-03-19 18:28:36 +0400
commit5a3da1fe9561828d0ca7eca664b16ec2b9bf0055 (patch)
treeb7bbaabf1271af7d912e9bdbb7f5810d2d0a5d3e /include
parent271648b4c610eed540daaf9ff366209825757565 (diff)
downloadlinux-5a3da1fe9561828d0ca7eca664b16ec2b9bf0055.tar.xz
inet: limit length of fragment queue hash table bucket lists
This patch introduces a constant limit of the fragment queue hash table bucket list lengths. Currently the limit 128 is choosen somewhat arbitrary and just ensures that we can fill up the fragment cache with empty packets up to the default ip_frag_high_thresh limits. It should just protect from list iteration eating considerable amounts of cpu. If we reach the maximum length in one hash bucket a warning is printed. This is implemented on the caller side of inet_frag_find to distinguish between the different users of inet_fragment.c. I dropped the out of memory warning in the ipv4 fragment lookup path, because we already get a warning by the slab allocator. Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Jesper Dangaard Brouer <jbrouer@redhat.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/inet_frag.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 76c3fe5ecc2e..0a1dcc2fa2f5 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -43,6 +43,13 @@ struct inet_frag_queue {
#define INETFRAGS_HASHSZ 64
+/* averaged:
+ * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
+ * rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
+ * struct frag_queue))
+ */
+#define INETFRAGS_MAXDEPTH 128
+
struct inet_frags {
struct hlist_head hash[INETFRAGS_HASHSZ];
/* This rwlock is a global lock (seperate per IPv4, IPv6 and
@@ -76,6 +83,8 @@ int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force);
struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
struct inet_frags *f, void *key, unsigned int hash)
__releases(&f->lock);
+void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
+ const char *prefix);
static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
{