This fixes a couple of skyzaller crashes. Most

of them have to do with TFO. Even the default stack
had one of the issues:

1) We need to make sure for rack that we don't advance
   snd_nxt beyond iss when we are not doing fast open. We
   otherwise can get a bunch of SYN's sent out incorrectly
   with the seq number advancing.
2) When we complete the 3-way handshake we should not ever
   append to reassembly if the tlen is 0, if TFO is enabled
   prior to this fix we could still call the reasemmbly. Note
   this effects all three stacks.
3) Rack like its cousin BBR should track if a SYN is on a
   send map entry.
4) Both bbr and rack need to only consider len incremented on a SYN
   if the starting seq is iss, otherwise we don't increment len which
   may mean we return without adding a sendmap entry.

This work was done in collaberation with Michael Tuexen, thanks for
all the testing!
Sponsored by:	Netflix Inc
Differential Revision:	https://reviews.freebsd.org/D25000

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/netinet/tcp_stacks/tcp_rack.h b/sys/netinet/tcp_stacks/tcp_rack.h
index e8f74d65f788..f60e49b65e6c 100644
--- a/sys/netinet/tcp_stacks/tcp_rack.h
+++ b/sys/netinet/tcp_stacks/tcp_rack.h
@@ -39,6 +39,7 @@
 #define RACK_RWND_COLLAPSED 0x0100/* The peer collapsed the rwnd on the segment */
 #define RACK_APP_LIMITED    0x0200/* We went app limited after this send */
 #define RACK_WAS_ACKED	    0x0400/* a RTO undid the ack, but it already had a rtt calc done */
+#define RACK_HAS_SIN	    0x0800/* SIN is on this guy */
 #define RACK_NUM_OF_RETRANS 3
 
 #define RACK_INITIAL_RTO 1000 /* 1 second in milli seconds */