Commit Graph

12 Commits

Author SHA1 Message Date
Jonathan Lemon
6b33ceb8e3 When expanding a syncache entry into a socket, inherit the socket options
from the current listen socket instead of the cached (and possibly stale)
TCB pointer.
2002-02-20 16:47:11 +00:00
Jonathan Lemon
0cab7c4b08 When a duplicate SYN arrives which matches an entry in the syncache,
update our lazy reference to the inpcb structure, as it may have changed.

Found by: dima
2002-02-12 02:03:50 +00:00
Julian Elischer
079b7badea Pre-KSE/M3 commit.
this is a low-functionality change that changes the kernel to access the main
thread of a process via the linked list of threads rather than
assuming that it is embedded in the process. It IS still embeded there
but remove all teh code that assumes that in preparation for the next commit
which will actually move it out.

Reviewed by: peter@freebsd.org, gallatin@cs.duke.edu, benno rice,
2002-02-07 20:58:47 +00:00
Jonathan Lemon
d9b7cc1c8d The ENDPTS_EQ macro was comparing the one of the fports to itself. Fix.
Submitted by: emy@boostworks.com
2002-01-22 17:54:28 +00:00
Jonathan Lemon
45a0329051 If syncookies are disabled (net.inet.tcp.syncookies) then use the faster
arc4random() routine to generate ISNs instead of creating them with MD5().

Suggested by: silby
2001-12-21 04:41:08 +00:00
Jonathan Lemon
e579ba1aea When storing an int value in a void *, use intptr_t as the cast type
(instead of int) to keep the 64 bit platforms happy.
2001-12-19 15:57:43 +00:00
Jonathan Lemon
a9c9684163 Extend the SYN DoS defense by adding syncookies to the syncache.
All TCP ISNs that are sent out are valid cookies, which allows entries
in the syncache to be dropped and still have the ACK accepted later.
As all entries pass through the syncache, there is no sudden switchover
from cache -> cookies when the cache is full; instead, syncache entries
simply have a reduced lifetime.  More details may be found in the
"Resisting DoS attacks with a SYN cache" paper in the Usenix BSDCon 2002
conference proceedings.

Sponsored by: DARPA, NAI Labs
2001-12-19 06:12:14 +00:00
Jonathan Lemon
04cad5adb1 Undo one of my last minute changes; move sc_iss up earlier so it
is initialized in case we take the T/TCP path.
2001-12-13 04:05:26 +00:00
Matthew Dillon
262c1c1a4e Fix a bug with transmitter restart after receiving a 0 window. The
receiver was not sending an immediate ack with delayed acks turned on
when the input buffer is drained, preventing the transmitter from
restarting immediately.

Propogate the TCP_NODELAY option to accept()ed sockets.  (Helps tbench and
is a good idea anyway).

Some cleanup.  Identify additonal issues in comments.

MFC after:	1 day
2001-12-02 08:49:29 +00:00
Seigo Tanimura
df89626872 Clear a new syncache entry first, followed by filling in values. This
fixes route breakage due to uncleared gabage on my box.
2001-11-27 11:55:28 +00:00
Bruce Evans
419d3454b1 Fixed a buffer overrun. In my kernel configuration, tcp_syncache happens
to be followed by nfsnodehashtbl, so bzeroing callouts beyond the end of
tcp_syncache soon caused a null pointer panic when nfsnodehashtbl was
accessed.
2001-11-23 12:31:27 +00:00
Jonathan Lemon
be2ac88c59 Introduce a syncache, which enables FreeBSD to withstand a SYN flood
DoS in an improved fashion over the existing code.

Reviewed by: silby  (in a previous iteration)
Sponsored by: DARPA, NAI Labs
2001-11-22 04:50:44 +00:00