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| author | Hannes Frederic Sowa <hannes@stressinduktion.org> | 2013-03-15 11:32:30 +0000 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-03-27 02:41:07 +0000 |
| commit | 0d14440d5614de0e9d0239e7a2870f271db3af39 (patch) | |
| tree | 94f16f3fbc15e5add009f9d4728d5858437da5d6 /include/net | |
| parent | 3cf15fabc14a9dd490ace2410a1da3a8d5434505 (diff) | |
| download | lwn-0d14440d5614de0e9d0239e7a2870f271db3af39.tar.gz lwn-0d14440d5614de0e9d0239e7a2870f271db3af39.zip | |
inet: limit length of fragment queue hash table bucket lists
[ Upstream commit 5a3da1fe9561828d0ca7eca664b16ec2b9bf0055 ]
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/inet_frag.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h index 16ff29a7bb30..b289bd286d77 100644 --- a/include/net/inet_frag.h +++ b/include/net/inet_frag.h @@ -33,6 +33,13 @@ 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]; rwlock_t lock; @@ -64,6 +71,8 @@ int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f); 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) { |