With the first part of my previous Summer of Code work, we get:
-made libalias modular:
-support for 'particular' protocols (like ftp/irc/etcetc) is no more
hardcoded inside libalias, but it's available through external
modules loadable at runtime
-modules are available both in kernel (/boot/kernel/alias_*.ko) and
user land (/lib/libalias_*)
-protocols/applications modularized are: cuseeme, ftp, irc, nbt, pptp,
skinny and smedia
-added logging support for kernel side
-cleanup
After a buildworld, do a 'mergemaster -i' to install the file libalias.conf
in /etc or manually copy it.
During startup (and after every HUP signal) user land applications running
the new libalias will try to read a file in /etc called libalias.conf:
that file contains the list of modules to load.
User land applications affected by this commit are ppp and natd:
if libalias.conf is present in /etc you won't notice any difference.
The only kernel land bit affected by this commit is ng_nat:
if you are using ng_nat, and it doesn't correctly handle
ftp/irc/etcetc sessions anymore, remember to kldload
the correspondent module (i.e. kldload alias_ftp).
General information and details about the inner working are available
in the libalias man page under the section 'MODULAR ARCHITECTURE
(AND ipfw(4) SUPPORT)'.
NOTA BENE: this commit affects _ONLY_ libalias, ipfw in-kernel nat
support will be part of the next libalias-related commit.
Approved by: glebius
Reviewed by: glebius, ru
libalias.
In /usr/src/lib/libalias/alias.c, the functions LibAliasIn and
LibAliasOutTry call the legacy PacketAliasIn/PacketAliasOut instead
of LibAliasIn/LibAliasOut when the PKT_ALIAS_REVERSE option is set.
In this case, the context variable "la" gets lost because the legacy
compatibility routines expect "la" to be global. This was obviously
an oversight when rewriting the PacketAlias* functions to the
LibAlias* functions.
The fix (as shown in the patch below) is to remove the legacy
subroutine calls and replace with the new ones using the "la" struct
as the first arg.
Submitted by: Gil Kloepfer <fgil@kloepfer.org>
Confirmed by: <nicolai@catpipe.net>
PR: 76839
MFC after: 3 days
a libalias application (e.g. natd, ppp, etc.) to crash. Note: Skinny support
is not enabled in natd or ppp by default.
Approved by: secteam (nectar)
MFC after: 1 day
Secuiryt: This fixes a remote DoS exploit
functions. Basically, the ip_next() function was used to get the PPTP and
Skinny headers when tcp_next() should have been used instead. Symptoms of
this included a segfault in natd when trying to process a PPTP or Skinny
packet.
Approved by: des
{ip,udp,tcp} header and return a void * pointing to the payload (i.e. the
first byte past the end of the header and any required padding). Use them
consistently throughout libalias to a) reduce code duplication, b) improve
code legibility, c) get rid of a bunch of alignment warnings.
a short pointer. The previous implementation seems to be in a gray zone
of the C standard, and GCC generates incorrect code for it at -O2 or
higher on some platforms.
named link, foo_link or link_foo to lnk, foo_lnk or lnk_foo, fixing
signed / unsigned comparisons, and shoving unused function arguments
under the carpet.
I was hoping WARNS?=6 might reveal more serious problems, and perhaps
the source of the -O2 breakage, but found no smoking gun.
Makes it possible to have multiple packet aliasing instances in a
single process by moving all static and global variables into an
instance structure called "struct libalias".
Redefine a new API based on s/PacketAlias/LibAlias/g
Add new "instance" argument to all functions in the new API.
Implement old API in terms of the new API.
Skinny is the protocol used by Cisco IP phones to talk to Cisco Call
Managers. With this code, one can use a Cisco IP phone behind a FreeBSD
NAT gateway.
Currently, having the Call Manager behind the NAT gateway is not supported.
More information on enabling Skinny support in libalias, natd, and ppp
can be found in those applications' manpages.
PR: 55843
Reviewed by: ru
Approved by: ru
MFC after: 30 days
binaries in /bin and /sbin installed in /lib. Only the versioned files
reside in /lib, the .so symlink continues to live /usr/lib so the
toolchain doesn't need to be modified.
is not called, and no static rules match an outgoing packet, the
latter retains its source IP address. This is in support of the
"static NAT only" mode.
no punch_fw was used.
Fix another couple of bugs which prevented rules from being
installed properly.
On passing, use IPFW2 instead of NEW_IPFW to compile the new code,
and slightly simplify the instruction generation 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.
