Tests for Sending TCP Segments Having the SYN-bit Set

Description

This set of tests focuses on the sending of SYN-segments moving the state of the TCP connection from CLOSED to SYN-SENT and possibly to CLOSED again.

The list of socket options with level IPPROTO_TCP affecting this behaviour is:

TCP_KEEPINIT
TCP_NOOPT

The list of sysctl-variables affecting the sending of SYN-segments is

net.inet.tcp.keepinit
net.inet.tcp.rexmit_drop_options
net.inet.tcp.sack.enable
net.inet.tcp.rfc1323
kern.ipc.maxsockbuf
net.inet.tcp.ecn.enable
net.inet.tcp.ecn.maxretries

Status

Name	Result FreeBSD 11.0	Result FreeBSD Head
snd-syn-with-default-options-ipv4	Unknown	Passed
snd-syn-with-default-options-ipv6	Unknown	Passed
snd-syn-without-options-ipv4	Unknown	Passed
snd-syn-without-options-ipv6	Unknown	Passed
snd-syn-rtx-keepinit-ipv4	Unknown	Passed
snd-syn-rtx-keepinit-ipv6	Unknown	Passed
snd-syn-rtx-max-number-ipv4	Unknown	Passed
snd-syn-rtx-max-number-ipv6	Unknown	Passed
snd-syn-rtx-drop-options-ipv4	Unknown	Passed (Note 1)
snd-syn-rtx-drop-options-ipv6	Unknown	Passed (Note 1)
snd-syn-mss-inherited-from-mtu-72-ipv4	Unknown	Passed
snd-syn-mss-inherited-from-mtu-9000-ipv4	Unknown	Passed
snd-syn-mss-inherited-from-mtu-65535-ipv4	Unknown	Passed
snd-syn-mss-inherited-from-mtu-1280-ipv6	Unknown	Passed
snd-syn-mss-inherited-from-mtu-9000-ipv6	Unknown	Failed (Note 2)
snd-syn-mss-inherited-from-mtu-65535-ipv6	Unknown	Failed (Note 2)
snd-syn-without-sack-ipv4	Unknown	Passed
snd-syn-without-sack-ipv6	Unknown	Passed
snd-syn-without-ws-and-ts-ipv4	Unknown	Passed
snd-syn-without-ws-and-ts-ipv6	Unknown	Passed
snd-syn-without-sack-and-ws-and-ts-ipv4	Unknown	Passed
snd-syn-without-sack-and-ws-and-ts-ipv6	Unknown	Passed
snd-syn-with-min-ws-ipv4	Unknown	Passed
snd-syn-with-min-ws-ipv6	Unknown	Passed
snd-syn-with-max-ws-ipv4	Unknown	Passed
snd-syn-with-max-ws-ipv6	Unknown	Passed
snd-syn-with-ecn-ipv4	Unknown	Passed
snd-syn-with-ecn-ipv6	Unknown	Passed
snd-syn-with-ecn-alt-maxretries-ipv4	Unknown	Passed
snd-syn-with-ecn-alt-maxretries-ipv6	Unknown	Passed

Notes

The sysctl variable net.inet.tcp.rexmit_drop_options is not described in the TCP(4) man page. The description of the sysctl variable (when displayed with sysctl -d net.inet.tcp.rexmit_drop_options states that no options will be used from the third and later retransmits of the SYN-segment. However, the MSS option is not dropped. Either change the code or change the documentation and add an entry to the man page.
The MSS is based on an MTU of 1500 bytes instead of the configured one.