FN(TCP_OVERWINDOW) \
FN(TCP_OFOMERGE) \
FN(TCP_RFC7323_PAWS) \
+ FN(TCP_OLD_SEQUENCE) \
FN(TCP_INVALID_SEQUENCE) \
FN(TCP_RESET) \
FN(TCP_INVALID_SYN) \
* LINUX_MIB_PAWSESTABREJECTED
*/
SKB_DROP_REASON_TCP_RFC7323_PAWS,
+ /** @SKB_DROP_REASON_TCP_OLD_SEQUENCE: Old SEQ field (duplicate packet) */
+ SKB_DROP_REASON_TCP_OLD_SEQUENCE,
/** @SKB_DROP_REASON_TCP_INVALID_SEQUENCE: Not acceptable SEQ field */
SKB_DROP_REASON_TCP_INVALID_SEQUENCE,
/** @SKB_DROP_REASON_TCP_RESET: Invalid RST packet */
* (borrowed from freebsd)
*/
-static inline bool tcp_sequence(const struct tcp_sock *tp, u32 seq, u32 end_seq)
+static enum skb_drop_reason tcp_sequence(const struct tcp_sock *tp,
+ u32 seq, u32 end_seq)
{
- return !before(end_seq, tp->rcv_wup) &&
- !after(seq, tp->rcv_nxt + tcp_receive_window(tp));
+ if (before(end_seq, tp->rcv_wup))
+ return SKB_DROP_REASON_TCP_OLD_SEQUENCE;
+
+ if (after(seq, tp->rcv_nxt + tcp_receive_window(tp)))
+ return SKB_DROP_REASON_TCP_INVALID_SEQUENCE;
+
+ return SKB_NOT_DROPPED_YET;
}
/* When we get a reset we do this. */
}
/* Step 1: check sequence number */
- if (!tcp_sequence(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq)) {
+ reason = tcp_sequence(tp, TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq);
+ if (reason) {
/* RFC793, page 37: "In all states except SYN-SENT, all reset
* (RST) segments are validated by checking their SEQ-fields."
* And page 69: "If an incoming segment is not acceptable,
} else if (tcp_reset_check(sk, skb)) {
goto reset;
}
- SKB_DR_SET(reason, TCP_INVALID_SEQUENCE);
goto discard;
}