At the same time, splice out a function and also rely on the compiler for overflow/underflow handling.
Found by inspection. Fixes: bd5e81a0e596 ("Userspace Datapath: Add ALG infra and FTP." Signed-off-by: Darrell Ball <dlu...@gmail.com> --- V2: Splice out a function and rely on the compiler to do the overflow/underflow. lib/conntrack.c | 37 ++++++++++--------------------------- 1 file changed, 10 insertions(+), 27 deletions(-) diff --git a/lib/conntrack.c b/lib/conntrack.c index 6f6021a..969cc7b 100644 --- a/lib/conntrack.c +++ b/lib/conntrack.c @@ -3168,6 +3168,13 @@ repl_ftp_v6_addr(struct dp_packet *pkt, struct ct_addr v6_addr_rep, return overall_delta; } +/* Increment/decrement a TCP sequence number. */ +static void +adj_seqnum(ovs_16aligned_be32 *val, int32_t inc) +{ + put_16aligned_be32(val, htonl(ntohl(get_16aligned_be32(val)) + inc)); +} + static void handle_ftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx, struct dp_packet *pkt, @@ -3250,33 +3257,9 @@ handle_ftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx, struct tcp_header *th = dp_packet_l4(pkt); if (do_seq_skew_adj && seq_skew != 0) { - if (ctx->reply != conn_for_expectation->seq_skew_dir) { - - uint32_t tcp_ack = ntohl(get_16aligned_be32(&th->tcp_ack)); - - if ((seq_skew > 0) && (tcp_ack < seq_skew)) { - /* Should not be possible; will be marked invalid. */ - tcp_ack = 0; - } else if ((seq_skew < 0) && (UINT32_MAX - tcp_ack < -seq_skew)) { - tcp_ack = (-seq_skew) - (UINT32_MAX - tcp_ack); - } else { - tcp_ack -= seq_skew; - } - ovs_be32 new_tcp_ack = htonl(tcp_ack); - put_16aligned_be32(&th->tcp_ack, new_tcp_ack); - } else { - uint32_t tcp_seq = ntohl(get_16aligned_be32(&th->tcp_seq)); - if ((seq_skew > 0) && (UINT32_MAX - tcp_seq < seq_skew)) { - tcp_seq = seq_skew - (UINT32_MAX - tcp_seq); - } else if ((seq_skew < 0) && (tcp_seq < -seq_skew)) { - /* Should not be possible; will be marked invalid. */ - tcp_seq = 0; - } else { - tcp_seq += seq_skew; - } - ovs_be32 new_tcp_seq = htonl(tcp_seq); - put_16aligned_be32(&th->tcp_seq, new_tcp_seq); - } + ctx->reply != conn_for_expectation->seq_skew_dir ? + adj_seqnum(&th->tcp_ack, -conn_for_expectation->seq_skew) : + adj_seqnum(&th->tcp_seq, conn_for_expectation->seq_skew); } th->tcp_csum = 0; -- 1.9.1 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev