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tcp: uninline tcp_oow_rate_limited()

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tcp_oow_rate_limited() is hardly used in fast path, there is
no point inlining it.

Signed-of-by: Eric Dumazet <edumazet@google.com>

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-03-16 21:06:20 -07:00 committed by David S. Miller
parent 1bfc4438a7
commit 7970ddc8f9
2 changed files with 32 additions and 30 deletions
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32
include/net/tcp.h
View File

@ -1216,36 +1216,8 @@ static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt,
return true; return true;
} }
/* Return true if we're currently rate-limiting out-of-window ACKs and bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
* thus shouldn't send a dupack right now. We rate-limit dupacks in int mib_idx, u32 *last_oow_ack_time);
* response to out-of-window SYNs or ACKs to mitigate ACK loops or DoS
* attacks that send repeated SYNs or ACKs for the same connection. To
* do this, we do not send a duplicate SYNACK or ACK if the remote
* endpoint is sending out-of-window SYNs or pure ACKs at a high rate.
*/
static inline bool tcp_oow_rate_limited(struct net *net,
const struct sk_buff *skb,
int mib_idx, u32 *last_oow_ack_time)
{
/* Data packets without SYNs are not likely part of an ACK loop. */
if ((TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq) &&
!tcp_hdr(skb)->syn)
goto not_rate_limited;
if (*last_oow_ack_time) {
s32 elapsed = (s32)(tcp_time_stamp - *last_oow_ack_time);
if (0 <= elapsed && elapsed < sysctl_tcp_invalid_ratelimit) {
NET_INC_STATS_BH(net, mib_idx);
return true; /* rate-limited: don't send yet! */
}
}
*last_oow_ack_time = tcp_time_stamp;
not_rate_limited:
return false; /* not rate-limited: go ahead, send dupack now! */
}
static inline void tcp_mib_init(struct net *net) static inline void tcp_mib_init(struct net *net)
{ {

30
net/ipv4/tcp_input.c
View File

@ -3321,6 +3321,36 @@ static int tcp_ack_update_window(struct sock *sk, const struct sk_buff *skb, u32
return flag; return flag;
} }
/* Return true if we're currently rate-limiting out-of-window ACKs and
* thus shouldn't send a dupack right now. We rate-limit dupacks in
* response to out-of-window SYNs or ACKs to mitigate ACK loops or DoS
* attacks that send repeated SYNs or ACKs for the same connection. To
* do this, we do not send a duplicate SYNACK or ACK if the remote
* endpoint is sending out-of-window SYNs or pure ACKs at a high rate.
*/
bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
int mib_idx, u32 *last_oow_ack_time)
{
/* Data packets without SYNs are not likely part of an ACK loop. */
if ((TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq) &&
!tcp_hdr(skb)->syn)
goto not_rate_limited;
if (*last_oow_ack_time) {
s32 elapsed = (s32)(tcp_time_stamp - *last_oow_ack_time);
if (0 <= elapsed && elapsed < sysctl_tcp_invalid_ratelimit) {
NET_INC_STATS_BH(net, mib_idx);
return true; /* rate-limited: don't send yet! */
}
}
*last_oow_ack_time = tcp_time_stamp;
not_rate_limited:
return false; /* not rate-limited: go ahead, send dupack now! */
}
/* RFC 5961 7 [ACK Throttling] */ /* RFC 5961 7 [ACK Throttling] */
static void tcp_send_challenge_ack(struct sock *sk, const struct sk_buff *skb) static void tcp_send_challenge_ack(struct sock *sk, const struct sk_buff *skb)
{ {