//
// Copyright (c) 2017 Michael Tuexen
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
//

// This script reproduces the duplicate accept issue reported in
// https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=217637
// Use only the syncache.

 0.00 `sysctl -w net.inet.tcp.syncookies_only=0`
+0.00 `sysctl -w net.inet.tcp.syncookies=0`
+0.00 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+0.00 fcntl(3, F_GETFL) = 0x02 (flags O_RDWR)
+0.00 fcntl(3, F_SETFL, O_RDWR | O_NONBLOCK) = 0
+0.00 bind(3, ..., ...) = 0
+0.00 listen(3, 10) = 0
+0.00 < S  0:0(0) win 65535 <mss 1460,nop,wscale 5>
+0.00 > S. 0:0(0) ack 1 win 65535 <mss 1460,nop,wscale 6>
+0.00 <  . 1:1(0) ack 1 win 8192
+0.00 accept(3, ..., ...) = 4
+0.00 < P. 1:46(45) ack 1 win 8192
+0.00 read(4, ..., 2000) = 45
+0.00 write(4, ..., 395) = 395
+0.00 > P. 1:396(395) ack 46 win 1026
+0.00 close(4) = 0
+0.00 > F. 396:396(0) ack 46 win 1026
+0.00 < P. 396:404(8) ack 396 win 8192
+0.00 > R  396:396(0) win 0
+0.00 accept(3, ..., ...) = -1 EWOULDBLOCK (Operation would block)
+1.00 < P. 1:54(53) ack 1 win 8192
+0.00 > R  1:1(0) win 0
+0.00 accept(3, ..., ...) = -1 EWOULDBLOCK (Operation would block)
+0.00 close(3) = 0
+0.00 `sysctl -w net.inet.tcp.syncookies=1`