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| author | Eric Dumazet <edumazet@google.com> | 2019-06-12 09:52:31 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-06-14 18:52:14 -0700 |
| commit | 2c51c6273c73ff04099f48fb42dfdd2acc7a1b70 (patch) | |
| tree | 5153110a521ecde10c1a23ee8fbeb79f495cd871 /net/packet | |
| parent | 8e8e2951e3095732d7e780c241f61ea130955a57 (diff) | |
| download | linux-2c51c6273c73ff04099f48fb42dfdd2acc7a1b70.tar.gz linux-2c51c6273c73ff04099f48fb42dfdd2acc7a1b70.tar.bz2 linux-2c51c6273c73ff04099f48fb42dfdd2acc7a1b70.zip | |
net/packet: implement shortcut in tpacket_rcv()
tpacket_rcv() can be hit under DDOS quite hard, since
it will always grab a socket spinlock, to eventually find
there is no room for an additional packet.
Using tcpdump [1] on a busy host can lead to catastrophic consequences,
because of all cpus spinning on a contended spinlock.
This replicates a similar strategy used in packet_rcv()
[1] Also some applications mistakenly use af_packet socket
bound to ETH_P_ALL only to send packets.
Receive queue is never drained and immediately full.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet')
| -rw-r--r-- | net/packet/af_packet.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 2d499679811a..860ca3e6abf5 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2193,6 +2193,12 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, if (!res) goto drop_n_restore; + /* If we are flooded, just give up */ + if (__packet_rcv_has_room(po, skb) == ROOM_NONE) { + atomic_inc(&po->tp_drops); + goto drop_n_restore; + } + if (skb->ip_summed == CHECKSUM_PARTIAL) status |= TP_STATUS_CSUMNOTREADY; else if (skb->pkt_type != PACKET_OUTGOING && |