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authorWillem de Bruijn <willemb@google.com>2015-05-12 11:56:49 -0400
committerDavid S. Miller <davem@davemloft.net>2015-05-13 15:43:00 -0400
commit3b3a5b0aab5b9ad345d4beb9a364a7dd02c23d40 (patch)
tree07714d34021e3505276c82d8c84c39324c4ddc97 /net/packet/internal.h
parent2ccdbaa6d55b0656244ba57c4b56765a0af76c0a (diff)
downloadlinux-3b3a5b0aab5b9ad345d4beb9a364a7dd02c23d40.tar.bz2
packet: rollover huge flows before small flows
Migrate flows from a socket to another socket in the fanout group not only when the socket is full. Start migrating huge flows early, to divert possible 4-tuple attacks without affecting normal traffic. Introduce fanout_flow_is_huge(). This detects huge flows, which are defined as taking up more than half the load. It does so cheaply, by storing the rxhashes of the N most recent packets. If over half of these are the same rxhash as the current packet, then drop it. This only protects against 4-tuple attacks. N is chosen to fit all data in a single cache line. Tested: Ran bench_rollover for 10 sec with 1.5 Mpps of single flow input. lpbb5:/export/hda3/willemb# ./bench_rollover -l 1000 -r -s cpu rx rx.k drop.k rollover r.huge r.failed 0 14 14 0 0 0 0 1 20 20 0 0 0 0 2 16 16 0 0 0 0 3 6168824 6168824 0 4867721 4867721 0 4 4867741 4867741 0 0 0 0 5 12 12 0 0 0 0 6 15 15 0 0 0 0 7 17 17 0 0 0 0 Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet/internal.h')
-rw-r--r--net/packet/internal.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/packet/internal.h b/net/packet/internal.h
index 22d7d778c5b7..a9d30a17c714 100644
--- a/net/packet/internal.h
+++ b/net/packet/internal.h
@@ -89,6 +89,8 @@ struct packet_fanout {
struct packet_rollover {
int sock;
+#define ROLLOVER_HLEN (L1_CACHE_BYTES / sizeof(u32))
+ u32 history[ROLLOVER_HLEN] ____cacheline_aligned;
} ____cacheline_aligned_in_smp;
struct packet_sock {