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