Commit Graph

76 Commits

Author SHA1 Message Date
cjc
94a234c212 Add a 'verrevpath' option that verifies the interface that a packet
comes in on is the same interface that we would route out of to get to
the packet's source address. Essentially automates an anti-spoofing
check using the information in the routing table.

Experimental. The usage and rule format for the feature may still be
subject to change.
2003-03-15 01:13:00 +00:00
mux
f1e4ff6b70 Oops, forgot to commit this file. This is part of the fix
for ipfw2 panics on sparc64.
2002-10-24 22:32:13 +00:00
luigi
e3c4c6c9da One bugfix and one new feature.
The bugfix (ipfw2.c) makes the handling of port numbers with
a dash in the name, e.g. ftp-data, consistent with old ipfw:
use \\ before the - to consider it as part of the name and not
a range separator.

The new feature (all this description will go in the manpage):

each rule now belongs to one of 32 different sets, which can
be optionally specified in the following form:

	ipfw add 100 set 23 allow ip from any to any

If "set N" is not specified, the rule belongs to set 0.

Individual sets can be disabled, enabled, and deleted with the commands:

	ipfw disable set N
	ipfw enable set N
	ipfw delete set N

Enabling/disabling of a set is atomic. Rules belonging to a disabled
set are skipped during packet matching, and they are not listed
unless you use the '-S' flag in the show/list commands.
Note that dynamic rules, once created, are always active until
they expire or their parent rule is deleted.
Set 31 is reserved for the default rule and cannot be disabled.

All sets are enabled by default. The enable/disable status of the sets
can be shown with the command

	ipfw show sets

Hopefully, this feature will make life easier to those who want to
have atomic ruleset addition/deletion/tests. Examples:

To add a set of rules atomically:

	ipfw disable set 18
	ipfw add ... set 18 ...		# repeat as needed
	ipfw enable set 18

To delete a set of rules atomically

	ipfw disable set 18
	ipfw delete set 18
	ipfw enable set 18

To test a ruleset and disable it and regain control if something
goes wrong:

	ipfw disable set 18
	ipfw add ... set 18 ...         # repeat as needed
	ipfw enable set 18 ; echo "done "; sleep 30 && ipfw disable set 18

    here if everything goes well, you press control-C before
    the "sleep" terminates, and your ruleset will be left
    active. Otherwise, e.g. if you cannot access your box,
    the ruleset will be disabled after the sleep terminates.

I think there is only one more thing that one might want, namely
a command to assign all rules in set X to set Y, so one can
test a ruleset using the above mechanisms, and once it is
considered acceptable, make it part of an existing ruleset.
2002-08-10 04:37:32 +00:00
luigi
7bf1404d8f Fix a panic when doing "ipfw add pipe 1 log ..."
Also synchronize ip_dummynet.c with the version in RELENG_4 to
ease MFC's.
2002-07-17 07:21:42 +00:00
luigi
d3091fc32b Implement keepalives for dynamic rules, so they will not expire
just because you leave your session idle.

Also, put in a fix for 64-bit architectures (to be revised).

In detail:

ip_fw.h

  * Reorder fields in struct ip_fw to avoid alignment problems on
    64-bit machines. This only masks the problem, I am still not
    sure whether I am doing something wrong in the code or there
    is a problem elsewhere (e.g. different aligmnent of structures
    between userland and kernel because of pragmas etc.)

  * added fields in dyn_rule to store ack numbers, so we can
    generate keepalives when the dynamic rule is about to expire

ip_fw2.c

  * use a local function, send_pkt(), to generate TCP RST for Reset rules;

  * save about 250 bytes by cleaning up the various snprintf()
    in ipfw_log() ...

  * ... and use twice as many bytes to implement keepalives
    (this seems to be working, but i have not tested it extensively).

Keepalives are generated once every 5 seconds for the last 20 seconds
of the lifetime of a dynamic rule for an established TCP flow.  The
packets are sent to both sides, so if at least one of the endpoints
is responding, the timeout is refreshed and the rule will not expire.

You can disable this feature with

        sysctl net.inet.ip.fw.dyn_keepalive=0

(the default is 1, to have them enabled).

MFC after: 1 day

(just kidding... I will supply an updated version of ipfw2 for
RELENG_4 tomorrow).
2002-07-14 23:47:18 +00:00
luigi
29f095d651 Remove one unused command name. 2002-07-08 22:39:19 +00:00
luigi
95e13a442b Implement the last 2-3 missing instructions for ipfw,
now it should support all the instructions of the old ipfw.

Fix some bugs in the user interface, /sbin/ipfw.

Please check this code against your rulesets, so i can fix the
remaining bugs (if any, i think they will be mostly in /sbin/ipfw).

Once we have done a bit of testing, this code is ready to be MFC'ed,
together with a bunch of other changes (glue to ipfw, and also the
removal of some global variables) which have been in -current for
a couple of weeks now.

MFC after: 7 days
2002-07-05 22:43:06 +00:00
luigi
a9ab854862 The new ipfw code.
This code makes use of variable-size kernel representation of rules
(exactly the same concept of BPF instructions, as used in the BSDI's
firewall), which makes firewall operation a lot faster, and the
code more readable and easier to extend and debug.

The interface with the rest of the system is unchanged, as witnessed
by this commit. The only extra kernel files that I am touching
are if_fw.h and ip_dummynet.c, which is quite tied to ipfw. In
userland I only had to touch those programs which manipulate the
internal representation of firewall rules).

The code is almost entirely new (and I believe I have written the
vast majority of those sections which were taken from the former
ip_fw.c), so rather than modifying the old ip_fw.c I decided to
create a new file, sys/netinet/ip_fw2.c .  Same for the user
interface, which is in sbin/ipfw/ipfw2.c (it still compiles to
/sbin/ipfw).  The old files are still there, and will be removed
in due time.

I have not renamed the header file because it would have required
touching a one-line change to a number of kernel files.

In terms of user interface, the new "ipfw" is supposed to accepts
the old syntax for ipfw rules (and produce the same output with
"ipfw show". Only a couple of the old options (out of some 30 of
them) has not been implemented, but they will be soon.

On the other hand, the new code has some very powerful extensions.
First, you can put "or" connectives between match fields (and soon
also between options), and write things like

ipfw add allow ip from { 1.2.3.4/27 or 5.6.7.8/30 } 10-23,25,1024-3000 to any

This should make rulesets slightly more compact (and lines longer!),
by condensing 2 or more of the old rules into single ones.

Also, as an example of how easy the rules can be extended, I have
implemented an 'address set' match pattern, where you can specify
an IP address in a format like this:

        10.20.30.0/26{18,44,33,22,9}

which will match the set of hosts listed in braces belonging to the
subnet 10.20.30.0/26 . The match is done using a bitmap, so it is
essentially a constant time operation requiring a handful of CPU
instructions (and a very small amount of memmory -- for a full /24
subnet, the instruction only consumes 40 bytes).

Again, in this commit I have focused on functionality and tried
to minimize changes to the other parts of the system. Some performance
improvement can be achieved with minor changes to the interface of
ip_fw_chk_t. This will be done later when this code is settled.

The code is meant to compile unmodified on RELENG_4 (once the
PACKET_TAG_* changes have been merged), for this reason
you will see #ifdef __FreeBSD_version in a couple of places.
This should minimize errors when (hopefully soon) it will be time
to do the MFC.
2002-06-27 23:02:18 +00:00
luigi
5259888148 Remove (almost all) global variables that were used to hold
packet forwarding state ("annotations") during ip processing.
The code is considerably cleaner now.

The variables removed by this change are:

        ip_divert_cookie        used by divert sockets
        ip_fw_fwd_addr          used for transparent ip redirection
        last_pkt                used by dynamic pipes in dummynet

Removal of the first two has been done by carrying the annotations
into volatile structs prepended to the mbuf chains, and adding
appropriate code to add/remove annotations in the routines which
make use of them, i.e. ip_input(), ip_output(), tcp_input(),
bdg_forward(), ether_demux(), ether_output_frame(), div_output().

On passing, remove a bug in divert handling of fragmented packet.
Now it is the fragment at offset 0 which sets the divert status of
the whole packet, whereas formerly it was the last incoming fragment
to decide.

Removal of last_pkt required a change in the interface of ip_fw_chk()
and dummynet_io(). On passing, use the same mechanism for dummynet
annotations and for divert/forward annotations.

option IPFIREWALL_FORWARD is effectively useless, the code to
implement it is very small and is now in by default to avoid the
obfuscation of conditionally compiled code.

NOTES:
 * there is at least one global variable left, sro_fwd, in ip_output().
   I am not sure if/how this can be removed.

 * I have deliberately avoided gratuitous style changes in this commit
   to avoid cluttering the diffs. Minor stule cleanup will likely be
   necessary

 * this commit only focused on the IP layer. I am sure there is a
   number of global variables used in the TCP and maybe UDP stack.

 * despite the number of files touched, there are absolutely no API's
   or data structures changed by this commit (except the interfaces of
   ip_fw_chk() and dummynet_io(), which are internal anyways), so
   an MFC is quite safe and unintrusive (and desirable, given the
   improved readability of the code).

MFC after: 10 days
2002-06-22 11:51:02 +00:00
luigi
f172dc1bd4 Remove custom definitions (IP_FW_TCPF_SYN etc.) of TCP header flags
which are the same as the original ones (TH_SYN etc.)
2002-05-13 10:21:13 +00:00
luigi
23cf222c81 Cleanup the interface to ip_fw_chk, two of the input arguments
were totally useless and have been removed.

ip_input.c, ip_output.c:
    Properly initialize the "ip" pointer in case the firewall does an
    m_pullup() on the packet.

    Remove some debugging code forgotten long ago.

ip_fw.[ch], bridge.c:
    Prepare the grounds for matching MAC header fields in bridged packets,
    so we can have 'etherfw' functionality without a lot of kernel and
    userland bloat.
2002-05-09 10:34:57 +00:00
alfred
357e37e023 Remove __P. 2002-03-19 21:25:46 +00:00
yar
ca1cc6602b Implement matching IP precedence in ipfw(4).
Submitted by:	Igor Timkin <ivt@gamma.ru>
2001-12-21 18:43:02 +00:00
luigi
f565e0a1df MFS: sync the ipfw/dummynet/bridge code with the one recently merged
into stable (mostly , but not only, formatting and comments changes).
2001-11-04 22:56:25 +00:00
joe
0dc5f6f003 A few more style changes picked up whilst working on an MFC to -stable. 2001-10-29 15:09:07 +00:00
joe
f4296b73c0 Fix some whitespace, and a comment that I missed in the last commit. 2001-10-29 14:08:51 +00:00
joe
c78b92c237 Clean up the style of this header file. 2001-10-29 04:41:28 +00:00
luigi
0fb106cc3f Two main changes here:
+ implement "limit" rules, which permit to limit the number of sessions
   between certain host pairs (according to masks). These are a special
   type of stateful rules, which might be of interest in some cases.
   See the ipfw manpage for details.

 + merge the list pointers and ipfw rule descriptors in the kernel, so
   the code is smaller, faster and more readable. This patch basically
   consists in replacing "foo->rule->bar" with "rule->bar" all over
   the place.
   I have been willing to do this for ages!

MFC after: 1 week
2001-09-27 23:44:27 +00:00
luigi
571d41f160 A bunch of minor changes to the code (see below) for readability, code size
and speed. No new functionality added (yet) apart from a bugfix.
MFC will occur in due time and probably in stages.

BUGFIX: fix a problem in old code which prevented reallocation of
the hash table for dynamic rules (there is a PR on this).

OTHER CHANGES: minor changes to the internal struct for static and dynamic rules.
Requires rebuild of ipfw binary.

Add comments to show how data structures are linked together.
(It probably makes no sense to keep the chain pointers separate
from actual rule descriptors. They will be hopefully merged soon.

keep a (sysctl-readable) counter for the number of static rules,
to speed up IP_FW_GET operations

initial support for a "grace time" for expired connections, so we
can set timeouts for closing connections to much shorter times.

merge zero_entry() and resetlog_entry(), they use basically the
same code.

clean up and reduce replication of code for removing rules,
both for readability and code size.

introduce a separate lifetime for dynamic UDP rules.

fix a problem in old code which prevented reallocation of
the hash table for dynamic rules (PR ...)

restructure dynamic rule descriptors

introduce some local variables to avoid multiple dereferencing of
pointer chains (reduces code size and hopefully increases speed).
2001-09-20 13:52:49 +00:00
phk
be4fee4a9b Introduce a new feature in IPFW: Check of the source or destination
address is configured on a interface.  This is useful for routers with
dynamic interfaces.  It is now possible to say:

        0100 allow       tcp from any to any established
        0200 skipto 1000 tcp from any to any
        0300 allow       ip from any to any
        1000 allow       tcp from 1.2.3.4 to me 22
        1010 deny        tcp from any to me 22
        1020 allow       tcp from any to any

and not have to worry about the behaviour if dynamic interfaces configure
new IP numbers later on.

The check is semi expensive (traverses the interface address list)
so it should be protected as in the above example if high performance
is a requirement.
2001-02-13 14:12:37 +00:00
luigi
bc66105b1d Sync with the bridge/dummynet/ipfw code already tested in stable.
In ip_fw.[ch] change a couple of variable and field names to
avoid having types, variables and fields with the same name.
2001-02-10 00:10:18 +00:00
luigi
afaf9310f9 MFS: bridge/ipfw/dummynet fixes (bridge.c will be committed separately) 2001-02-02 00:18:00 +00:00
rwatson
c4fb1f7419 o IPFW incorrectly handled filtering in the presence of previously
reserved and now allocated TCP flags in incoming packets.  This patch
  stops overloading those bits in the IP firewall rules, and moves
  colliding flags to a seperate field, ipflg.  The IPFW userland
  management tool, ipfw(8), is updated to reflect this change.  New TCP
  flags related to ECN are now included in tcp.h for reference, although
  we don't currently implement TCP+ECN.

o To use this fix without completely rebuilding, it is sufficient to copy
  ip_fw.h and tcp.h into your appropriate include directory, then rebuild
  the ipfw kernel module, and ipfw tool, and install both.  Note that a
  mismatch between module and userland tool will result in incorrect
  installation of firewall rules that may have unexpected effects.  This
  is an MFC candidate, following shakedown.  This bug does not appear
  to affect ipfilter.

Reviewed by:	security-officer, billf
Reported by:	Aragon Gouveia <aragon@phat.za.net>
2001-01-09 03:10:30 +00:00
billf
e80d3292ca Add new fields for more granularity:
IP: version, tos, ttl, len, id
	TCP: seq#, ack#, window size

Reviewed by:	silence on freebsd-{net,ipfw}
2000-10-02 03:03:31 +00:00
archie
2fcdc74c0a Remove obsolete comment. 2000-08-22 00:32:52 +00:00
dan
c3897dad80 Add tcpoptions to ipfw. This works much in the same way as ipoptions do.
It also squashes 99% of packet kiddie synflood orgies.  For example, to
rate syn packets without MSS,

ipfw pipe 10 config 56Kbit/s queue 10Packets
ipfw add pipe 10 tcp from any to any in setup tcpoptions !mss

Submitted by:  Richard A. Steenbergen <ras@e-gerbil.net>
2000-06-08 15:34:51 +00:00
luigi
e2bccbe2b7 Implement WF2Q+ in dummynet. 2000-06-08 09:45:23 +00:00
jake
961b97d434 Back out the previous change to the queue(3) interface.
It was not discussed and should probably not happen.

Requested by:		msmith and others
2000-05-26 02:09:24 +00:00
jake
d93fbc9916 Change the way that the queue(3) structures are declared; don't assume that
the type argument to *_HEAD and *_ENTRY is a struct.

Suggested by:	phk
Reviewed by:	phk
Approved by:	mdodd
2000-05-23 20:41:01 +00:00
luigi
0a7657b332 Support for stateful (dynamic) ipfw rules. They are very
similar to ipfilter's keep-state.

Look at the updated ipfw(8) manpage for details.

Approved-by: jordan
2000-02-10 14:17:40 +00:00
luigi
dba91948d0 Add ipfw hooks for the new dummynet features.
Support masks on TCP/UDP ports.

Minor cleanup of ip_fw_chk() to avoid repeated calls to PULLUP_TO
at each rule.
2000-01-08 11:31:43 +00:00
peter
15b9bcb121 Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot).  This is consistant with the other
BSD's who made this change quite some time ago.  More commits to come.
1999-12-29 04:46:21 +00:00
archie
a35284d781 Miscellaneous fixes/cleanups relating to ipfw and divert(4):
- Implement 'ipfw tee' (finally)
- Divert packets by calling new function divert_packet() directly instead
  of going through protosw[].
- Replace kludgey global variable 'ip_divert_port' with a function parameter
  to divert_packet()
- Replace kludgey global variable 'frag_divert_port' with a function parameter
  to ip_reass()
- style(9) fixes

Reviewed by:	julian, green
1999-12-06 00:43:07 +00:00
peter
3b842d34e8 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
green
11a38f2404 Correction: uid -> gid (comment) 1999-08-27 23:46:02 +00:00
luigi
66c7a5151f Implement probabilistic rule match in ipfw. Each rule can be associated
with a match probability to achieve non-deterministic behaviour of
the firewall. This can be extremely useful for testing purposes
such as simulating random packet drop without having to use dummynet
(which already does the same thing), and simulating multipath effects
and the associated out-of-order delivery (this time in conjunction
with dummynet).

The overhead on normal rules is just one comparison with 0.

Since it would have been trivial to implement this by just adding
a field to the ip_fw structure, I decided to do it in a
backward-compatible way (i.e. struct ip_fw is unchanged, and as a
consequence you don't need to recompile ipfw if you don't want to
use this feature), since this was also useful for -STABLE.

When, at some point, someone decides to change struct ip_fw, please
add a length field and a version number at the beginning, so userland
apps can keep working even if they are out of sync with the kernel.
1999-08-11 15:34:47 +00:00
green
d848a791d1 Make ipfw's logging more dynamic. Now, log will use the default limit
_or_ you may specify "log logamount number" to set logging specifically
the rule.
   In addition, "ipfw resetlog" has been added, which will reset the
logging counters on any/all rule(s). ipfw resetlog does not affect
the packet/byte counters (as ipfw reset does), and is the only "set"
command that can be run at securelevel >= 3.
   This should address complaints about not being able to set logging
amounts, not being able to restart logging at a high securelevel,
and not being able to just reset logging without resetting all of the
counters in a rule.
1999-08-01 16:57:24 +00:00
green
a8dcdb7b2f Correct a really gross comment format. 1999-07-28 22:22:57 +00:00
green
280f8f95b4 This is the much-awaited cleaned up version of IPFW [ug]id support.
All relevant changes have been made (including ipfw.8).
1999-06-19 18:43:33 +00:00
peter
f9bc841320 Tidy up some stray / unused stuff in the IPFW package and friends.
- unifdef -DCOMPAT_IPFW  (this was on by default already)
- remove traces of in-kernel ip_nat package, it was never committed.
- Make IPFW and DUMMYNET initialize themselves rather than depend on
  compiled-in hooks in ip_init().  This means they initialize the same
  way both in-kernel and as kld modules.  (IPFW initializes now :-)
1999-04-20 13:32:06 +00:00
luigi
4b628fa86d Last bits (i think) of dummynet for -current. 1998-12-14 18:09:13 +00:00
phk
256218ff32 Widen and change the layout of the IPFW structures flag element.
This will allow us to add dummynet to 3.0

Recompile /sbin/ipfw AND your kernel.
1998-09-02 19:14:01 +00:00
wollman
a76fb5eefa Yow! Completely change the way socket options are handled, eliminating
another specialized mbuf type in the process.  Also clean up some
of the cruft surrounding IPFW, multicast routing, RSVP, and other
ill-explored corners.
1998-08-23 03:07:17 +00:00
julian
22a5d80812 Support for IPFW based transparent forwarding.
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>
1998-07-06 03:20:19 +00:00
bde
ffbb93a37a Added #include of <sys/queue.h> so that this file is more "self"-sufficent. 1998-02-03 22:19:35 +00:00
alex
35f59936c3 Bump up packet and byte counters to 64-bit unsigned ints. As a
consequence, ipfw's list command now adjusts its output at runtime
based on the largest packet/byte counter values.

NOTE:
  o The ipfw struct has changed requiring a recompile of both kernel
    and userland ipfw utility.

  o This probably should not be brought into 2.2.

PR:		3738
1998-01-08 03:03:54 +00:00
bde
fb826377ff Removed unused #includes. 1997-10-28 15:59:26 +00:00
bde
1062c10a86 Fixed gratuitous ANSIisms. 1997-09-16 11:44:05 +00:00
alex
dc3ab85890 Support interface names up to 15 characters in length. In order to
accommodate the expanded name, the ICMP types bitmap has been
reduced from 256 bits to 32.

A recompile of kernel and user level ipfw is required.

To be merged into 2.2 after a brief period in -current.

PR:		bin/4209
Reviewed by:	Archie Cobbs <archie@whistle.com>
1997-08-08 14:36:29 +00:00
julian
18750f0354 Submitted by: Whistle Communications (archie Cobbs)
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.
1997-06-02 05:02:37 +00:00