and call it directly from tcp_slowtimo() (via a table) rather
than going through tcp_userreq().
This will allow us to call TCP timers directly from callouts,
in a future revision.
ISS attacks (which we already fend off quite well).
1. First-cut implementation of RFC1948, Steve Bellovin's cryptographic
hash method of generating TCP ISS values. Note, this code is experimental
and disabled by default (experimental enough that I don't export the
variable via sysctl yet, either). There are a couple of issues I'd
like to discuss with Steve, so this code should only be used by people
who really know what they're doing.
2. Per a recent thread on Bugtraq, it's possible to determine a system's
uptime by snooping the RFC1323 TCP timestamp options sent by a host; in
4.4BSD, timestamps are created by incrementing the tcp_now variable
at 2 Hz; there's even a company out there that uses this to determine
web server uptime. According to Newsham's paper "The Problem With
Random Increments", while NetBSD's TCP ISS generation method is much
better than the "random increment" method used by FreeBSD and OpenBSD,
it is still theoretically possible to mount an attack against NetBSD's
method if the attacker knows how many times the tcp_iss_seq variable
has been incremented. By not leaking uptime information, we can make
that much harder to determine. So, we avoid the leak by giving each
TCP connection a timebase of 0.
Without this, if a v6 address is placed before a v4 address in if_addrlist,
a PRU_PURGEIF request for v6 tcp protocol purges also v4 addresses and,
as a result, if_detach fails to request PRU_PURGEIF for v4 protocols
other than tcp.
it is not supposed to work.
logging fix: add "\n" to some of log() in in6_prefix.c.
improve in6_ifdetach(). now almost all structure depend on ifnet
will be cleared up.
possible loose ends:
- cached route_in6 in static varaiables needs to be cleared as well
- there are ifaddr manipulation without reference counting,
which should be fixed
we still see panics after card removal, though... not sure what is left.
(sync with kame)
although this version has been changed somewhat:
- reference counting on ifaddrs isn't as complete as Bill's original
work was. This is hard to get right, and we should attack one
protocol at a time.
- This doesn't do reference counting or dynamic allocation of ifnets yet.
- This version introduces a new PRU -- PRU_PURGEADDR, which is used to
purge an ifaddr from a protocol. The old method Bill used didn't work
on all protocols, and it only worked on some because it was Very Lucky.
This mostly works ... i.e. works for my USB Ethernet, except for a dangling
ifaddr reference left by the IPv6 code; have not yet tracked this down.
- interop issues in ipcomp is fixed
- padding type (after ESP) is configurable
- key database memory management (need more fixes)
- policy specification is revisited
XXX m->m_pkthdr.rcvif is still overloaded - hope to fix it soon
due to massive changes in KAME side.
- IPv6 output goes through nd6_output
- faith can capture IPv4 packets as well - you can run IPv4-to-IPv6 translator
using heavily modified DNS servers
- per-interface statistics (required for IPv6 MIB)
- interface autoconfig is revisited
- udp input handling has a big change for mapped address support.
- introduce in4_cksum() for non-overwriting checksumming
- introduce m_pulldown()
- neighbor discovery cleanups/improvements
- netinet/in.h strictly conforms to RFC2553 (no extra defs visible to userland)
- IFA_STATS is fixed a bit (not tested)
- and more more more.
TODO:
- cleanup os-independency #ifdef
- avoid rcvif dual use (for IPsec) to help ifdetach
(sorry for jumbo commit, I can't separate this any more...)
(Sorry for a big commit, I can't separate this into several pieces...)
Pls check sys/netinet6/TODO and sys/netinet6/IMPLEMENTATION for details.
- sys/kern: do not assume single mbuf, accept chained mbuf on passing
data from userland to kernel (or other way round).
- "midway" ATM card: ATM PVC pseudo device support, like those done in ALTQ
package (ftp://ftp.csl.sony.co.jp/pub/kjc/).
- sys/netinet/tcp*: IPv4/v6 dual stack tcp support.
- sys/netinet/{ip6,icmp6}.h, sys/net/pfkeyv2.h: IETF document assumes those
file to be there so we patch it up.
- sys/netinet: IPsec additions are here and there.
- sys/netinet6/*: most of IPv6 code sits here.
- sys/netkey: IPsec key management code
- dev/pci/pcidevs: regen
In my understanding no code here is subject to export control so it
should be safe.
TCP connections by using the MTU of the interface. Also added
a knob, mss_ifmtu, to force all connections to use the MTU of
the interface to calculate the advertised MSS.
so_linger is used as an argument to tsleep(), so was stuffed with
clockticks for the TCP linger time. However, so_linger is set directly from
l_linger if the linger time is specified, and l_linger is seconds (although
this is not currently documented anywhere). Fix this to set the TCP
linger time in seconds, and multiply so_linger by hz when tsleep() is
called to actually perform the linger.
The sysctl'able variable "tcp_init_win", when set to 0, selects an
auto-tuning algorithm for selecting the initial window, based on transmit
segment size, per discussion in the IETF tcpimpl working group.
Default initial window is still 1 segment, but will soon become 2 segments,
per discussion in tcpimpl.
a socket, just calling tcp_disconnect() on the tcpcb will do the right thing.
From Thorsten Frueauf <frueauf@ira.uka.de> and W. Richard Stevens in PR/3738
resp. TCP/IP Illustrated, Vol. 2.
