Commit 3284f492 authored by Ryan Stone's avatar Ryan Stone
Browse files

LRO: Don't merge ACK and non-ACK packets together

LRO was willing to merge ACK and non-ACK packets together.  This
can cause incorrect th_ack values to be reported up the stack.
While non-ACKs are quite unlikely to appear in practice, LRO's
behaviour is against the spec.  Make LRO unwilling to merge
packets with different TH_ACK flag values in order to fix the
issue.

Found by: Sysunit test
Differential Revision:	https://reviews.freebsd.org/D33775
Reviewed by: rrs
parent 24fe6643
......@@ -921,6 +921,7 @@ tcp_set_entry_to_mbuf(struct lro_ctrl *lc, struct lro_entry *le,
le->next_seq = ntohl(th->th_seq) + tcp_data_len;
le->ack_seq = th->th_ack;
le->window = th->th_win;
le->flags = th->th_flags;
le->needs_merge = 0;
/* Setup new data pointers. */
......@@ -1092,10 +1093,12 @@ tcp_lro_condense(struct lro_ctrl *lc, struct lro_entry *le)
}
/* Try to append the new segment. */
if (__predict_false(ntohl(th->th_seq) != le->next_seq ||
((th->th_flags & TH_ACK) !=
(le->flags & TH_ACK)) ||
(tcp_data_len == 0 &&
le->ack_seq == th->th_ack &&
le->window == th->th_win))) {
/* Out of order packet or duplicate ACK. */
/* Out of order packet, non-ACK + ACK or dup ACK. */
tcp_push_and_replace(lc, le, m);
goto again;
}
......
......@@ -146,8 +146,9 @@ struct lro_entry {
uint16_t compressed;
uint16_t uncompressed;
uint16_t window;
uint16_t timestamp : 1;
uint16_t needs_merge : 1;
uint8_t flags;
uint8_t timestamp : 1;
uint8_t needs_merge : 1;
struct bintime alloc_time; /* time when entry was allocated */
};
......
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