l4p/tcp: few fixes for sending RST packet logic

- for RST on RTO use SND.NXT instead of SND.UNA
- for RST on invalid SEQSEG.ACK in SYN-SENT state:
  - use SEG.ACK
  - don't terminate the connection

Change-Id: I9943f6fdfb89493af4b0437c5a81af34c450c630
Signed-off-by: Jielong Zhou <jielong.zjl@antfin.com>
Signed-off-by: Jianfeng Tan <henry.tjf@antfin.com>
Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

diff --git a/lib/libtle_l4p/tcp_rxtx.c b/lib/libtle_l4p/tcp_rxtx.c
index c0a0dd1..e785b9a 100644 (file)
--- a/lib/libtle_l4p/tcp_rxtx.c
+++ b/lib/libtle_l4p/tcp_rxtx.c
@@ -1554,9 +1554,15 @@ rx_synack(struct tle_tcp_stream *s, uint32_t ts, uint32_t state,
        if (state != TCP_ST_SYN_SENT)
                return -EINVAL;
 
-       /* invalid SEG.SEQ */
+       /*
+        * RFC 793 3.9: in the SYN-SENT state
+        * If SEG.ACK =< ISS, or SEG.ACK > SND.NXT, send a reset
+        * <SEQ=SEG.ACK><CTL=RST>
+        * and discard the segment.
+        * The connection remains in the same state.
+        */
        if (si->ack != (uint32_t)s->tcb.snd.nxt) {
-               rsp->flags = TCP_FLAG_RST;
+               send_rst(s, si->ack);
                return 0;
        }
 
@@ -1711,10 +1717,7 @@ rx_stream(struct tle_tcp_stream *s, uint32_t ts,
                i = 0;
 
        /* we have a response packet to send. */
-       if (rsp.flags == TCP_FLAG_RST) {
-               send_rst(s, si[i].ack);
-               stream_term(s);
-       } else if (rsp.flags != 0) {
+       if (rsp.flags != 0) {
                send_ack(s, ts, rsp.flags);
 
                /* start the timer for FIN packet */
@@ -2590,7 +2593,7 @@ rto_stream(struct tle_tcp_stream *s, uint32_t tms)
                timer_restart(s);
 
        } else {
-               send_rst(s, s->tcb.snd.una);
+               send_rst(s, s->tcb.snd.nxt);
                stream_term(s);
        }
 }