Any packet that can be matched by a ipfw rule can be redirected
transparently to another port or machine. Redirection to another port
mostly makes sense with tcp, where a session can be set up
between a proxy and an unsuspecting client. Redirection to another machine
requires that the other machine also be expecting to receive the forwarded
packets, as their headers will not have been modified.
/sbin/ipfw must be recompiled!!!
Reviewed by: Peter Wemm <peter@freebsd.org>
Submitted by: Chrisy Luke <chrisy@flix.net>
Remove lots'o'hacks.
looutput is now static.
Other callers who want to use loopback to allow shortcutting
should call the special entrypoint for this, if_simloop(), which is
specifically designed for this purpose. Using looutput for this purpose
was problematic, particularly with bpf and trying to keep track
of whether one should be using the charateristics of the loopback interface
or the interface (e.g. if_ethersubr.c) that was requesting the loopback.
There was a whole class of errors due to this mis-use each of which had
hacks to cover them up.
Consists largly of hack removal :-)
so that the new behaviour is now default.
Solves the "infinite loop in diversion" problem when more than one diversion
is active.
Man page changes follow.
The new code is in -stable as the NON default option.
Prior to this change, Accidental recursion protection was done by
the diverted daemon feeding back the divert port number it got
the packet on, as the port number on a sendto(). IPFW knew not to
redivert a packet to this port (again). Processing of the ruleset
started at the beginning again, skipping that divert port.
The new semantic (which is how we should have done it the first time)
is that the port number in the sendto() is the rule number AFTER which
processing should restart, and on a recvfrom(), the port number is the
rule number which caused the diversion. This is much more flexible,
and also more intuitive. If the user uses the same sockaddr received
when resending, processing resumes at the rule number following that
that caused the diversion. The user can however select to resume rule
processing at any rule. (0 is restart at the beginning)
To enable the new code use
option IPFW_DIVERT_RESTART
This should become the default as soon as people have looked at it a bit
so it must be adjusted (minus 1) before using it to do the length check.
I'm not sure who to give the credit to, but the bug was reported by
Jennifer Dawn Myers <jdm@enteract.com>, who also supplied a patch. It
was also fixed in OpenBSD previously by andreas.gunnarsson@emw.ericsson.se,
and of course I did the homework to verify that the fix was correct per
the specification.
PR: 6738
NetBSD, ported to FreeBSD by Pierre Beyssac <pb@fasterix.freenix.org> and
minorly tweaked by me.
This is a standard part of FreeBSD, but must be enabled with:
"sysctl -w net.inet.ip.fastforwarding=1" ...and of course forwarding must
also be enabled. This should probably be modified to use the zone
allocator for speed and space efficiency. The current algorithm also
appears to lose if the number of active paths exceeds IPFLOW_MAX (256),
in which case it wastes lots of time trying to figure out which cache
entry to drop.
"time" wasn't a atomic variable, so splfoo() protection were needed
around any access to it, unless you just wanted the seconds part.
Most uses of time.tv_sec now uses the new variable time_second instead.
gettime() changed to getmicrotime(0.
Remove a couple of unneeded splfoo() protections, the new getmicrotime()
is atomic, (until Bruce sets a breakpoint in it).
A couple of places needed random data, so use read_random() instead
of mucking about with time which isn't random.
Add a new nfs_curusec() function.
Mark a couple of bogosities involving the now disappeard time variable.
Update ffs_update() to avoid the weird "== &time" checks, by fixing the
one remaining call that passwd &time as args.
Change profiling in ncr.c to use ticks instead of time. Resolution is
the same.
Add new function "tvtohz()" to avoid the bogus "splfoo(), add time, call
hzto() which subtracts time" sequences.
Reviewed by: bde
It controls if the system is to accept source routed packets.
It used to be such that, no matter if the setting of net.inet.ip.sourceroute,
source routed packets destined at us would be accepted. Now it is
controllable with eth default set to NOT accept those.
This means that a FreeBSD will only forward source routed packets
when both net.inet.ip.forwarding and net.inet.ip.sourceroute are set
to 1.
You can hit me now ;-)
Submitted by: Thomas Ptacek
close small security hole where an atacker could sendpackets with
IPDIVERT protocol, and select how it would be diverted thus bypassing
the ipfirewall. Discovered by inspection rather than attack.
(you'd have to know how the firewall was configured (EXACTLY) to
make use of this but..)
hope i've found out all files that actually depend on this dependancy.
IMHO, it's not very good practice to change the size of internal
structs depending on kernel options.
these are quite extensive additions to the ipfw code.
they include a change to the API because the old method was
broken, but the user view is kept the same.
The new code allows a particular match to skip forward to a particular
line number, so that blocks of rules can be
used without checking all the intervening rules.
There are also many more ways of rejecting
connections especially TCP related, and
many many more ...
see the man page for a complete description.
to fill in the nfs_diskless structure, at the cost of some kernel
bloat. The advantage is that this code works on a wider range of
network adapters than netboot. Several new kernel options are
documented in LINT.
Obtained from: parts of the code comes from NetBSD.
affect programs that sit on top of divert(4) sockets. The
multicast routing code already unconditionally zeros the sum
before recalculating.
Any code that unconditionaly sums a packet without first zeroing
the sum (assuming that it's already zero'd) will break. No such
code seems to exist.
set it in the first place, independent of whether sin->sin_port
is set.
The result is that diverted packets that are being forwarded
will be diverted once and only once on the way in (ip_input())
and again, once and only once on the way out (ip_output()) -
twice in total. ICMP packets that don't contain a port will
now also be diverted.
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
to TAILQs. Fix places which referenced these for no good reason
that I can see (the references remain, but were fixed to compile
again; they are still questionable).
using a sockaddr_dl.
Fix the other packet-information socket options (SO_TIMESTAMP, IP_RECVDSTADDR)
to work for multicast UDP and raw sockets as well. (They previously only
worked for unicast UDP).
This stuff should not be too destructive if the IPDIVERT is not compiled in..
be aware that this changes the size of the ip_fw struct
so ipfw needs to be recompiled to use it.. more changes coming to clean this up.
gcc only inlines memcpy()'s whose count is constant and didn't inline
these. I want memcpy() in the kernel go away so that it's obvious that
it doesn't need to be optimized. Now it is only used for one struct
copy in si.c.
Close the ip-fragment hole.
Waste less memory.
Rewrite to contemporary more readable style.
Kill separate IPACCT facility, use "accept" rules in IPFIREWALL.
Filter incoming >and< outgoing packets.
Replace "policy" by sticky "deny all" rule.
Rules have numbers used for ordering and deletion.
Remove "rerorder" code entirely.
Count packet & bytecount matches for rules.
Code in -current & -stable is now the same.
to enable IP forwarding, use sysctl(8). Also did the same for IPX,
which involved inventing a completely new MIB from whole cloth (which
I may not quite have correct); be aware of this if you use IPX forwarding.
(The two should never have been controlled by the same option anyway.)
net.inet.ip.intr-queue-maxlen (=== ipintrq.ifq_maxlen)
and net.inet.ip.intr-queue-drops (=== ipintrq.ifq_drops)
There should probably be a standard way of getting the same information
going the other way.
there may even be LKMs.) Also, change the internal name of `unixdomain'
to `localdomain' since AF_LOCAL is now the preferred name of this family.
Declare netisr correctly and in the right place.
high load:
1) If there ever get to be more than net.inet.ip.rtmaxcache entries
in the cache, in_rtqtimo() will reduce net.inet.ip.rtexpire by
1/3 and do another round, unles net.inet.ip.rtexpire is less than
net.inet.ip.rtminexpire, and never more than once in ten minutes
(rtq_timeout).
2) If net.inet.ip.rtexpire is set to zero, don't bother to cache
anything.
1) Firewall is not subdivided on forwarding / blocking chains
anymore.Actually only one chain left-it was the blocking one.
2) LKM support.ip_fwdef.c is function pointers definition and
goes into kernel along with all INET stuff.
to something more recent than the ancient 1.2 release contained in
4.4. This code has the following advantages as compared to
previous versions (culled from the README file for the SunOS release):
- True multicast delivery
- Configurable rate-limiting of forwarded multicast traffic on each
physical interface or tunnel, using a token-bucket limiter.
- Simplistic classification of packets for prioritized dropping.
- Administrative scoping of multicast address ranges.
- Faster detection of hosts leaving groups.
- Support for multicast traceroute (code not yet available).
- Support for RSVP, the Resource Reservation Protocol.
What still needs to be done:
- The multicast forwarder needs testing.
- The multicast routing daemon needs to be ported.
- Network interface drivers need to have the `#ifdef MULTICAST' goop ripped
out of them.
- The IGMP code should probably be bogon-tested.
Some notes about the porting process:
In some cases, the Berkeley people decided to incorporate functionality from
later releases of the multicast code, but then had to do things differently.
As a result, if you look at Deering's patches, and then look at
our code, it is not always obvious whether the patch even applies. Let
the reader beware.
I ran ip_mroute.c through several passes of `unifdef' to get rid of
useless grot, and to permanently enable the RSVP support, which we will
include as standard.
Ported by: Garrett Wollman
Submitted by: Steve Deering and Ajit Thyagarajan (among others)
- Delete redundant declarations.
- Add -Wredundant-declarations to Makefile.i386 so they don't come back.
- Delete sloppy COMMON-style declarations of uninitialized data in
header files.
- Add a few prototypes.
- Clean up warnings resulting from the above.
NB: ioconf.c will still generate a redundant-declaration warning, which
is unavoidable unless somebody volunteers to make `config' smarter.
