bridged packets only, soon to come also for packets on ordinary
ether_input() and ether_output() paths. The syntax is
ipfw add <action> MAC dst src type
where dst and src can be "any" or a MAC address optionallyfollowed
by a mask, e.g.
10:20:30:40:50
10:20:30:40:50/32
10:20:30:40:50&ff:ff:ff:f0:ff:0f
and type can be a single ethernet type, a range, or a type followed by
a mask (values are always in hexadecimal) e.g.
0800
0800-0806
0800/8
0800&03ff
Note, I am still uncertain on what is the best format for inputting
these values, having the values in hexadecimal is convenient in most
cases but can be confusing sometimes. Suggestions welcome.
Implement suggestion from PR 37778 to allow "not me" on destination
and source IP. The code in the PR was slightly wrong and interfered
with the normal handling of IP addresses. This version hopefully is
correct.
Minor cleanup of the code, in some places moving the indentation to 4
spaces because the code was becoming too deep. Eventually, in a
separate commit, I will move the whole file to 4 space indent.
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.
more on how ipfw(8) deals with tiny fragments. While we're at it, add
a quick log message to even let people know we dropped a packet. (Note
that the second FINE POINT is somewhat redundant given the first, but
since the code is there, leave the docs for it.)
MFC after: 1 day
so that after the first time we can follow the pointer instead
of having to scan the list.
This was the intended behaviour from day one.
PR: 34639
MFC-after: 3 days
deprecated in favor of the POSIX-defined lowercase variants.
o Change all occurrences of NTOHL() and associated marcros in the
source tree to use the lowercase function variants.
o Add missing license bits to sparc64's <machine/endian.h>.
Approved by: jake
o Clean up <machine/endian.h> files.
o Remove unused __uint16_swap_uint32() from i386's <machine/endian.h>.
o Remove prototypes for non-existent bswapXX() functions.
o Include <machine/endian.h> in <arpa/inet.h> to define the
POSIX-required ntohl() family of functions.
o Do similar things to expose the ntohl() family in libstand, <netinet/in.h>,
and <sys/param.h>.
o Prepend underscores to the ntohl() family to help deal with
complexities associated with having MD (asm and inline) versions, and
having to prevent exposure of these functions in other headers that
happen to make use of endian-specific defines.
o Create weak aliases to the canonical function name to help deal with
third-party software forgetting to include an appropriate header.
o Remove some now unneeded pollution from <sys/types.h>.
o Add missing <arpa/inet.h> includes in userland.
Tested on: alpha, i386
Reviewed by: bde, jake, tmm
kern.ipc.showallsockets is set to 0.
Submitted by: billf (with modifications by me)
Inspired by: Dave McKay (aka pm aka Packet Magnet)
Reviewed by: peter
MFC after: 2 weeks
+ 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
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).
about rules and dynamic rules. it later fills this buffer with these
rules.
it also takes the opporunity to compare the expiration of the dynamic
rules with the current time and either marks them for deletion or simply
charges the countdown.
unfortunatly it does this all (the sizing, the buffer copying, and the
expiration GC) with no spl protection whatsoever. it was possible for
the dynamic rule(s) to be ripped out from under the request before it
had completed, resulting in corrupt memory dereferencing.
Reviewed by: ps
MFC before: 4.4-RELEASE, hopefully.
sysctl, net.inet.ip.fw.permanent_rules.
This allows you to install rules that are persistent across flushes,
which is very useful if you want a default set of rules that
maintains your access to remote machines while you're reconfiguring
the other rules.
Reviewed by: Mark Murray <markm@FreeBSD.org>
When we recieve a fragmented TCP packet (other than the first) we can't
extract header information (we don't have state to reference). In a rather
unelegant fashion we just move on and assume a non-match.
Recent additions to the TCP header-specific section of the code neglected
to add the logic to the fragment code so in those cases the match was
assumed to be positive and those parts of the rule (which should have
resulted in a non-match/continue) were instead skipped (which means
the processing of the rule continued even though it had already not
matched).
Fault can be spread out over Rich Steenbergen (tcpoptions) and myself
(tcp{seq,ack,win}).
rwatson sent me a patch that got me thinking about this whole situation
(but what I'm committing / this description is mine so don't blame him).
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.
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>
of IP datagram. This fixes the problem when firewall denied fragmented
packets whose last fragment was less than minimum protocol header size.
Found by: Harti Brandt <brandt@fokus.gmd.de>
PR: kern/22309
enough into the mbuf data area. Solve this problem once and for all
by pulling up the entire (standard) header for TCP and UDP, and four
bytes of header for ICMP (enough for type, code and cksum fields).
the IP_FW_IF_IPID rule. (We have recently decided to keep the
ip_id field in network byte order inside the kernel, see revision
1.140 of src/sys/netinet/ip_input.c).
I did not like to have the conversion happen in userland, and I
think that the similar conversions for fw_tcp(seq|ack|win) should
be moved out of userland (src/sbin/ipfw/ipfw.c) into the kernel.
for them does not belong in the IP_FW_F_COMMAND switch, that mask doesn't even
apply to them(!).
2. You cannot add a uid/gid rule to something that isn't TCP, UDP, or IP.
XXX - this should be handled in ipfw(8) as well (for more diagnostic output),
but this at least protects bogus rules from being added.
Pointy hat: green
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>
