This particular implementation is designed to be fully backwards compatible
and to be MFC-able to 7.x (and 6.x)
Currently the only protocol that can make use of the multiple tables is IPv4
Similar functionality exists in OpenBSD and Linux.
From my notes:
-----
One thing where FreeBSD has been falling behind, and which by chance I
have some time to work on is "policy based routing", which allows
different
packet streams to be routed by more than just the destination address.
Constraints:
------------
I want to make some form of this available in the 6.x tree
(and by extension 7.x) , but FreeBSD in general needs it so I might as
well do it in -current and back port the portions I need.
One of the ways that this can be done is to have the ability to
instantiate multiple kernel routing tables (which I will now
refer to as "Forwarding Information Bases" or "FIBs" for political
correctness reasons). Which FIB a particular packet uses to make
the next hop decision can be decided by a number of mechanisms.
The policies these mechanisms implement are the "Policies" referred
to in "Policy based routing".
One of the constraints I have if I try to back port this work to
6.x is that it must be implemented as a EXTENSION to the existing
ABIs in 6.x so that third party applications do not need to be
recompiled in timespan of the branch.
This first version will not have some of the bells and whistles that
will come with later versions. It will, for example, be limited to 16
tables in the first commit.
Implementation method, Compatible version. (part 1)
-------------------------------
For this reason I have implemented a "sufficient subset" of a
multiple routing table solution in Perforce, and back-ported it
to 6.x. (also in Perforce though not always caught up with what I
have done in -current/P4). The subset allows a number of FIBs
to be defined at compile time (8 is sufficient for my purposes in 6.x)
and implements the changes needed to allow IPV4 to use them. I have not
done the changes for ipv6 simply because I do not need it, and I do not
have enough knowledge of ipv6 (e.g. neighbor discovery) needed to do it.
Other protocol families are left untouched and should there be
users with proprietary protocol families, they should continue to work
and be oblivious to the existence of the extra FIBs.
To understand how this is done, one must know that the current FIB
code starts everything off with a single dimensional array of
pointers to FIB head structures (One per protocol family), each of
which in turn points to the trie of routes available to that family.
The basic change in the ABI compatible version of the change is to
extent that array to be a 2 dimensional array, so that
instead of protocol family X looking at rt_tables[X] for the
table it needs, it looks at rt_tables[Y][X] when for all
protocol families except ipv4 Y is always 0.
Code that is unaware of the change always just sees the first row
of the table, which of course looks just like the one dimensional
array that existed before.
The entry points rtrequest(), rtalloc(), rtalloc1(), rtalloc_ign()
are all maintained, but refer only to the first row of the array,
so that existing callers in proprietary protocols can continue to
do the "right thing".
Some new entry points are added, for the exclusive use of ipv4 code
called in_rtrequest(), in_rtalloc(), in_rtalloc1() and in_rtalloc_ign(),
which have an extra argument which refers the code to the correct row.
In addition, there are some new entry points (currently called
rtalloc_fib() and friends) that check the Address family being
looked up and call either rtalloc() (and friends) if the protocol
is not IPv4 forcing the action to row 0 or to the appropriate row
if it IS IPv4 (and that info is available). These are for calling
from code that is not specific to any particular protocol. The way
these are implemented would change in the non ABI preserving code
to be added later.
One feature of the first version of the code is that for ipv4,
the interface routes show up automatically on all the FIBs, so
that no matter what FIB you select you always have the basic
direct attached hosts available to you. (rtinit() does this
automatically).
You CAN delete an interface route from one FIB should you want
to but by default it's there. ARP information is also available
in each FIB. It's assumed that the same machine would have the
same MAC address, regardless of which FIB you are using to get
to it.
This brings us as to how the correct FIB is selected for an outgoing
IPV4 packet.
Firstly, all packets have a FIB associated with them. if nothing
has been done to change it, it will be FIB 0. The FIB is changed
in the following ways.
Packets fall into one of a number of classes.
1/ locally generated packets, coming from a socket/PCB.
Such packets select a FIB from a number associated with the
socket/PCB. This in turn is inherited from the process,
but can be changed by a socket option. The process in turn
inherits it on fork. I have written a utility call setfib
that acts a bit like nice..
setfib -3 ping target.example.com # will use fib 3 for ping.
It is an obvious extension to make it a property of a jail
but I have not done so. It can be achieved by combining the setfib and
jail commands.
2/ packets received on an interface for forwarding.
By default these packets would use table 0,
(or possibly a number settable in a sysctl(not yet)).
but prior to routing the firewall can inspect them (see below).
(possibly in the future you may be able to associate a FIB
with packets received on an interface.. An ifconfig arg, but not yet.)
3/ packets inspected by a packet classifier, which can arbitrarily
associate a fib with it on a packet by packet basis.
A fib assigned to a packet by a packet classifier
(such as ipfw) would over-ride a fib associated by
a more default source. (such as cases 1 or 2).
4/ a tcp listen socket associated with a fib will generate
accept sockets that are associated with that same fib.
5/ Packets generated in response to some other packet (e.g. reset
or icmp packets). These should use the FIB associated with the
packet being reponded to.
6/ Packets generated during encapsulation.
gif, tun and other tunnel interfaces will encapsulate using the FIB
that was in effect withthe proces that set up the tunnel.
thus setfib 1 ifconfig gif0 [tunnel instructions]
will set the fib for the tunnel to use to be fib 1.
Routing messages would be associated with their
process, and thus select one FIB or another.
messages from the kernel would be associated with the fib they
refer to and would only be received by a routing socket associated
with that fib. (not yet implemented)
In addition Netstat has been edited to be able to cope with the
fact that the array is now 2 dimensional. (It looks in system
memory using libkvm (!)). Old versions of netstat see only the first FIB.
In addition two sysctls are added to give:
a) the number of FIBs compiled in (active)
b) the default FIB of the calling process.
Early testing experience:
-------------------------
Basically our (IronPort's) appliance does this functionality already
using ipfw fwd but that method has some drawbacks.
For example,
It can't fully simulate a routing table because it can't influence the
socket's choice of local address when a connect() is done.
Testing during the generating of these changes has been
remarkably smooth so far. Multiple tables have co-existed
with no notable side effects, and packets have been routes
accordingly.
ipfw has grown 2 new keywords:
setfib N ip from anay to any
count ip from any to any fib N
In pf there seems to be a requirement to be able to give symbolic names to the
fibs but I do not have that capacity. I am not sure if it is required.
SCTP has interestingly enough built in support for this, called VRFs
in Cisco parlance. it will be interesting to see how that handles it
when it suddenly actually does something.
Where to next:
--------------------
After committing the ABI compatible version and MFCing it, I'd
like to proceed in a forward direction in -current. this will
result in some roto-tilling in the routing code.
Firstly: the current code's idea of having a separate tree per
protocol family, all of the same format, and pointed to by the
1 dimensional array is a bit silly. Especially when one considers that
there is code that makes assumptions about every protocol having the
same internal structures there. Some protocols don't WANT that
sort of structure. (for example the whole idea of a netmask is foreign
to appletalk). This needs to be made opaque to the external code.
My suggested first change is to add routing method pointers to the
'domain' structure, along with information pointing the data.
instead of having an array of pointers to uniform structures,
there would be an array pointing to the 'domain' structures
for each protocol address domain (protocol family),
and the methods this reached would be called. The methods would have
an argument that gives FIB number, but the protocol would be free
to ignore it.
When the ABI can be changed it raises the possibilty of the
addition of a fib entry into the "struct route". Currently,
the structure contains the sockaddr of the desination, and the resulting
fib entry. To make this work fully, one could add a fib number
so that given an address and a fib, one can find the third element, the
fib entry.
Interaction with the ARP layer/ LL layer would need to be
revisited as well. Qing Li has been working on this already.
This work was sponsored by Ironport Systems/Cisco
Reviewed by: several including rwatson, bz and mlair (parts each)
Obtained from: Ironport systems/Cisco
the limit in bytes) hard coded into both the kernel and userland.
Make both these limits a sysctl, so it is easy to change the limit.
If the userland part of ipfw finds that the sysctls don't exist,
it will just fall back to the traditional limits.
(100 packets is quite a small limit these days. If you want to test
TCP at 100Mbps, 100 packets can only accommodate a DBP of 12ms.)
Note these sysctls in the man page and warn against increasing them
without thinking first.
MFC after: 3 weeks
table 'values' as IP addresses, use an explicit argument (-i).
This is a 'POLA' issue. This is a low risk change and should be MFC'd
to RELENG_6 and RELENG 7. it might be put as an errata item for 6.3.
(not sure about 6.2).
Fix suggested by: Eugene Grosbein
PR: 120720
MFC After: 3 days
exposing them to all consumers of ip_fw.h. These structures are
used in both ipfw(8) and ipfw(4), but not part of the user<->kernel
interface for other applications to use, rather, shared
implementation.
MFC after: 3 days
Reported by: Paul Vixie <paul at vix dot com>
$ ipfw -n add 1 allow layer2 not mac-type ip
00001 allow ip from any to any layer2 not not mac-type 0x0800
PR: bin/115372
Submitted by: Andrey V. Elsukov
Approved by: re (hrs)
MFC after: 3 weeks
pack a set number correctly.
Submitted by: oleg
o Plug a memory leak.
Submitted by: oleg and Andrey V. Elsukov
Approved by: re (kensmith)
MFC after: 1 week
- to show a specific set: ipfw set 3 show
- to delete rules from the set: ipfw set 9 delete 100 200 300
- to flush the set: ipfw set 4 flush
- to reset rules counters in the set: ipfw set 1 zero
PR: kern/113388
Submitted by: Andrey V. Elsukov
Approved by: re (kensmith)
MFC after: 6 weeks
Before:
$ ipfw -n add 100 count icmp from any to any mac-type 0x01
00100 count icmp 0x0001
$ ipfw -n add 100 count icmp from any to any mac any any
00100 count icmp MAC any any any
After:
$ ipfw -n add 100 count icmp from any to any mac-type 0x01
00100 count icmp from any to any mac-type 0x0001
$ ipfw -n add 100 count icmp from any to any mac any any
00100 count icmp from any to any MAC any any
PR: bin/112244
Submitted by: Andrey V. Elsukov
MFC after: 1 month
With the second (and last) part of my previous Summer of Code work, we get:
-ipfw's in kernel nat
-redirect_* and LSNAT support
General information about nat syntax and some examples are available
in the ipfw (8) man page. The redirect and LSNAT syntax are identical
to natd, so please refer to natd (8) man page.
To enable in kernel nat in rc.conf, two options were added:
o firewall_nat_enable: equivalent to natd_enable
o firewall_nat_interface: equivalent to natd_interface
Remember to set net.inet.ip.fw.one_pass to 0, if you want the packet
to continue being checked by the firewall ruleset after being
(de)aliased.
NOTA BENE: due to some problems with libalias architecture, in kernel
nat won't work with TSO enabled nic, thus you have to disable TSO via
ifconfig (ifconfig foo0 -tso).
Approved by: glebius (mentor)
otherwise this command
ipfw add allow ipv6-icmp from any to 2002::1 icmp6types 1,2,128,129
turns into icmp6types 1,2,32,33,34,...94,95,128,129
PR: 102422 (part 1)
Submitted by: Andrey V. Elsukov <bu7cher at yandex.ru>
MFC after: 5 days
having trouble with the "me6" keyword. Also, we were using inet_pton on
the wrong variable in one place.
Reviewed by: mlaier (previous version of patch)
Obtained from: Sascha Blank (inet_pton change)
MFC after: 1 week
for example:
fwd tablearg ip from any to table(1)
where table 1 has entries of the form:
1.1.1.0/24 10.2.3.4
208.23.2.0/24 router2
This allows trivial implementation of a secondary routing table implemented
in the firewall layer.
I expect more work (under discussion with Glebius) to follow this to clean
up some of the messy parts of ipfw related to tables.
Reviewed by: Glebius
MFC after: 1 month
- 'tag' & 'untag' action parameters.
- 'tagged' & 'limit' rule options.
Rule examples:
pipe 1 tag tablearg ip from table(1) to any
allow ip from any to table(2) tagged tablearg
allow tcp from table(3) to any 25 setup limit src-addr tablearg
sbin/ipfw/ipfw2.c:
1) new macros
GET_UINT_ARG - support of 'tablearg' keyword, argument range checking.
PRINT_UINT_ARG - support of 'tablearg' keyword.
2) strtoport(): do not silently truncate/accept invalid port list expressions
like: '1,2-abc' or '1,2-3-4' or '1,2-3x4'. style(9) cleanup.
Approved by: glebius (mentor)
MFC after: 1 month
Since tags are kept while packet resides in kernelspace, it's possible to
use other kernel facilities (like netgraph nodes) for altering those tags.
Submitted by: Andrey Elsukov <bu7cher at yandex dot ru>
Submitted by: Vadim Goncharov <vadimnuclight at tpu dot ru>
Approved by: glebius (mentor)
Idea from: OpenBSD PF
MFC after: 1 month
doesn't exist or add one that is already present, if the -q flag
is set. Useful for "ipfw -q /dev/stdin" when the command above is
invoked from something like python or TCL to feed commands
down the throat of ipfw.
MFC in: 1 week
action argument with the value obtained from table lookup. The feature
is now applicable only to "pipe", "queue", "divert", "tee", "netgraph"
and "ngtee" rules.
An example usage:
ipfw pipe 1000 config bw 1000Kbyte/s
ipfw pipe 4000 config bw 4000Kbyte/s
ipfw table 1 add x.x.x.x 1000
ipfw table 1 add x.x.x.y 4000
ipfw pipe tablearg ip from table(1) to any
In the example above the rule will throw different packets to different pipes.
TODO:
- Support "skipto" action, but without searching all rules.
- Improve parser, so that it warns about bad rules. These are:
- "tablearg" argument to action, but no "table" in the rule. All
traffic will be blocked.
- "tablearg" argument to action, but "table" searches for entry with
a specific value. All traffic will be blocked.
- "tablearg" argument to action, and two "table" looks - for src and
for dst. The last lookup will match.
IPv6 support was committed:
- Stop treating `ip' and `ipv6' as special in `proto' option as they
conflict with /etc/protocols.
- Disuse `ipv4' in `proto' option as it is corresponding to `ipv6'.
- When protocol is specified as numeric, treat it as it is even it is
41 (ipv6).
- Allow zero for protocol as it is valid number of `ip'.
Still, we cannot specify an IPv6 over an IPv4 tunnel like before such
as:
pass ipv6 from any to any
But, now, you can specify it like:
pass ip4 from any to any proto ipv6
PR: kern/89472
Reported by: Ga l Roualland <gael.roualland__at__dial.oleane.com>
MFC after: 1 week
* Correct handling of IPv6 Extension Headers.
* Add unreach6 code.
* Add logging for IPv6.
Submitted by: sysctl handling derived from patch from ume needed for ip6fw
Obtained from: is_icmp6_query and send_reject6 derived from similar
functions of netinet6,ip6fw
Reviewed by: ume, gnn; silence on ipfw@
Test setup provided by: CK Software GmbH
MFC after: 6 days
This is the last requirement before we can retire ip6fw.
Reviewed by: dwhite, brooks(earlier version)
Submitted by: dwhite (manpage)
Silence from: -ipfw
This commit replaces those with two new functions that simplify the code
and produce warnings that the syntax is deprecated. A small number of
sensible abbreviations may be explicitly added based on user feedback.
There were previously three types of strncmp use in ipfw:
- Most commonly, strncmp(av, "string", sizeof(av)) was used to allow av
to match string or any shortened form of it. I have replaced this
with a new function _substrcmp(av, "string") which returns 0 if av
is a substring of "string", but emits a warning if av is not exactly
"string".
- The next type was two instances of strncmp(av, "by", 2) which allowed
the abbreviation of bytes to "by", "byt", etc. Unfortunately, it
also supported "bykHUygh&*g&*7*ui". I added a second new function
_substrcmp2(av, "by", "bytes") which acts like the strncmp did, but
complains if the user doesn't spell out the word "bytes".
- There is also one correct use of strncmp to match "table(" which might
have another token after it without a space.
Since I changed all the lines anyway, I also fixed the treatment of
strncmp's return as a boolean in many cases. I also modified a few
strcmp cases as well to be fully consistent.
contain O_UID, O_GID and O_JAIL opcodes, the F_NOT or F_OR logical
operator bits get clobbered. Making it impossible to use the ``NOT'' or
``OR'' operators with uid, gid and jail based constraints.
The ipfw_insn instruction template contains a ``len'' element which
stores two pieces of information, the size of the instruction
(in 32-bit words) in the low 6 bits of "len" with the 2 remaining
bits to implement OR and NOT.
The current code clobbers the OR and NOT bits by initializing the
``len'' element to the size, rather than OR'ing the bits. This change
fixes this by changing the initialization of cmd->len to an OR operation
for the O_UID, O_GID and O_JAIL opcodes.
This may be a MFC candidate for RELENG_5.
Reviewed by: andre
Approved by: luigi
PR: kern/63961 (partially)
keyword but without 'logamount' limit the amount of their log messages
by net.inet.ip.fw.verbose_limit sysctl value.
RELENG_5 candidate.
PR: kern/46080
Submitted by: Dan Pelleg
MFC after: 1 week
Since the only thing truly unique about a prison is it's ID, I figured
this would be the most granular way of handling this.
This commit makes the following changes:
- Adds tokenizing and parsing for the ``jail'' command line option
to the ipfw(8) userspace utility.
- Append the ipfw opcode list with O_JAIL.
- While Iam here, add a comment informing others that if they
want to add additional opcodes, they should append them to the end
of the list to avoid ABI breakage.
- Add ``fw_prid'' to the ipfw ucred cache structure.
- When initializing ucred cache, if the process is jailed,
set fw_prid to the prison ID, otherwise set it to -1.
- Update man page to reflect these changes.
This change was a strong motivator behind the ucred caching
mechanism in ipfw.
A sample usage of this new functionality could be:
ipfw add count ip from any to any jail 2
It should be noted that because ucred based constraints
are only implemented for TCP and UDP packets, the same
applies for jail associations.
Conceptual head nod by: pjd
Reviewed by: rwatson
Approved by: bmilekic (mentor)
For incoming packets, the packet's source address is checked if it
belongs to a directly connected network. If the network is directly
connected, then the interface the packet came on in is compared to
the interface the network is connected to. When incoming interface
and directly connected interface are not the same, the packet does
not match.
Usage example:
ipfw add deny ip from any to any not antispoof in
Manpage education by: ru
o Add sanity checking to the firewall delete operation
which tells the user that a firewall rule
specification is required.
The previous behaviour was to exit without reporting any
errors to the user.
Approved by: bmilekic (mentor)
mac ipfw rules. The exact same sanity check is performed as
the first operation of add_mac(), so there is no sense
in doing it twice.
Approved by: bmilekic (mentor)
PR: bin/55981
source address of a packet exists in the routing table. The
default route is ignored because it would match everything and
render the check pointless.
This option is very useful for routers with a complete view of
the Internet (BGP) in the routing table to reject packets with
spoofed or unrouteable source addresses.
Example:
ipfw add 1000 deny ip from any to any not versrcreach
also known in Cisco-speak as:
ip verify unicast source reachable-via any
Reviewed by: luigi
rule, thus omitting the entire body.
This makes the output a lot more readable for complex rulesets
(provided, of course, you have annotated your ruleset appropriately!)
MFC after: 3 days
if_xname, if_dname, and if_dunit. if_xname is the name of the interface
and if_dname/unit are the driver name and instance.
This change paves the way for interface renaming and enhanced pseudo
device creation and configuration symantics.
Approved By: re (in principle)
Reviewed By: njl, imp
Tested On: i386, amd64, sparc64
Obtained From: NetBSD (if_xname)
of do_cmd() broke things, because this function assumes that a socklen_t
is large enough to hold a pointer.
A real solution to this problem would be a rewrite of do_cmd() to
treat the optlen parameter consistently and not use it to carry
a pointer or integer dependent on the context.
Allow set 31 to be used for rules other than 65535.
Set 31 is still special because rules belonging to it are not deleted
by the "ipfw flush" command, but must be deleted explicitly with
"ipfw delete set 31" or by individual rule numbers.
This implement a flexible form of "persistent rules" which you might
want to have available even after an "ipfw flush".
Note that this change does not violate POLA, because you could not
use set 31 in a ruleset before this change.
Suggested by: Paul Richards
introduced in the latest commits).
Also:
* update the 'ipfw -h' output;
* allow rules of the form "100 add allow ..." i.e. with the index first.
(requested by Paul Richards). This was an undocumented ipfw1 behaviour,
and it is left undocumented.
and minor code cleanups.
