them mostly with packet tags (one case is handled by using an mbuf flag
since the linkage between "caller" and "callee" is direct and there's no
need to incur the overhead of a packet tag).
This is (mostly) work from: sam
Silence from: -arch
Approved by: bms(mentor), sam, rwatson
This is the first of two commits; bringing in the kernel support first.
This can be enabled by compiling a kernel with options TCP_SIGNATURE
and FAST_IPSEC.
For the uninitiated, this is a TCP option which provides for a means of
authenticating TCP sessions which came into being before IPSEC. It is
still relevant today, however, as it is used by many commercial router
vendors, particularly with BGP, and as such has become a requirement for
interconnect at many major Internet points of presence.
Several parts of the TCP and IP headers, including the segment payload,
are digested with MD5, including a shared secret. The PF_KEY interface
is used to manage the secrets using security associations in the SADB.
There is a limitation here in that as there is no way to map a TCP flow
per-port back to an SPI without polluting tcpcb or using the SPD; the
code to do the latter is unstable at this time. Therefore this code only
supports per-host keying granularity.
Whilst FAST_IPSEC is mutually exclusive with KAME IPSEC (and thus IPv6),
TCP_SIGNATURE applies only to IPv4. For the vast majority of prospective
users of this feature, this will not pose any problem.
This implementation is output-only; that is, the option is honoured when
responding to a host initiating a TCP session, but no effort is made
[yet] to authenticate inbound traffic. This is, however, sufficient to
interwork with Cisco equipment.
Tested with a Cisco 2501 running IOS 12.0(27), and Quagga 0.96.4 with
local patches. Patches for tcpdump to validate TCP-MD5 sessions are also
available from me upon request.
Sponsored by: sentex.net
used for the ICMP reply source in reponse to packets which are not
directly addressed to us. By default continue with with normal
source selection.
Reviewed by: bms
at packet arrival.
For benchmarking purposes SO_BINTIME is preferable to SO_TIMEVAL
since it has higher resolution and lower overhead. Simultaneous
use of the two options is possible and they will return consistent
timestamps.
This introduces an extra test and a function call for SO_TIMEVAL, but I have
not been able to measure that.
ifconfig(8) flag since header for version 2 is the same but IP payload
is prepended with additional 4-bytes field.
Inspired by: Roman Synyuk <roman@univ.kiev.ua>
MFC after: 2 weeks
recwin and sendwin. This removes a big source of confusion and makes
following the code much easier.
Reviewed by: sam (mentor)
Obtained from: DragonFlyBSD rev 1.6 (hsu)
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.
tcp6_usr_bind(), tcp_usr_connect(), and tcp6_usr_connect() before checking
to see whether the address is multicast so that the proper errno value
will be returned if sa_len is incorrect. The checks are identical to the
ones in in_pcbbind_setup(), in6_pcbbind(), and in6_pcbladdr(), which are
called after the multicast address check passes.
MFC after: 30 days
resource exhaustion attacks.
For network link optimization TCP can adjust its MSS and thus
packet size according to the observed path MTU. This is done
dynamically based on feedback from the remote host and network
components along the packet path. This information can be
abused to pretend an extremely low path MTU.
The resource exhaustion works in two ways:
o during tcp connection setup the advertized local MSS is
exchanged between the endpoints. The remote endpoint can
set this arbitrarily low (except for a minimum MTU of 64
octets enforced in the BSD code). When the local host is
sending data it is forced to send many small IP packets
instead of a large one.
For example instead of the normal TCP payload size of 1448
it forces TCP payload size of 12 (MTU 64) and thus we have
a 120 times increase in workload and packets. On fast links
this quickly saturates the local CPU and may also hit pps
processing limites of network components along the path.
This type of attack is particularly effective for servers
where the attacker can download large files (WWW and FTP).
We mitigate it by enforcing a minimum MTU settable by sysctl
net.inet.tcp.minmss defaulting to 256 octets.
o the local host is reveiving data on a TCP connection from
the remote host. The local host has no control over the
packet size the remote host is sending. The remote host
may chose to do what is described in the first attack and
send the data in packets with an TCP payload of at least
one byte. For each packet the tcp_input() function will
be entered, the packet is processed and a sowakeup() is
signalled to the connected process.
For example an attack with 2 Mbit/s gives 4716 packets per
second and the same amount of sowakeup()s to the process
(and context switches).
This type of attack is particularly effective for servers
where the attacker can upload large amounts of data.
Normally this is the case with WWW server where large POSTs
can be made.
We mitigate this by calculating the average MSS payload per
second. If it goes below 'net.inet.tcp.minmss' and the pps
rate is above 'net.inet.tcp.minmssoverload' defaulting to
1000 this particular TCP connection is resetted and dropped.
MITRE CVE: CAN-2004-0002
Reviewed by: sam (mentor)
MFC after: 1 day
restore the general pre-randomid behaviour.
Setting the ip_id to zero causes several problems with
packet reassembly when a device along the path removes
the DF bit for some reason.
Other BSD and Linux have found and fixed the same issues.
PR: kern/60889
Tested by: Richard Wendland <richard@wendland.org.uk>
Approved by: re (scottl)
rfc3042 Limited retransmit
rfc3390 Increasing TCP's initial congestion Window
inflight TCP inflight bandwidth limiting
All my production server have it enabled and there have been no
issues. I am confident about having them on by default and it gives
us better overall TCP performance.
Reviewed by: sam (mentor)
are acting as router (ipforwarding enabled).
This doesn't fix the problem that host routes from ICMP redirects
are never removed from the kernel routing table but removes the
problem for machines doing packet forwarding.
Reviewed by: sam (mentor)
if_gre.c rev.1.41-1.49
o Spell output with two ts.
o Remove assigned-to but not used variable.
o fix grammatical error in a diagnostic message.
o u_short -> u_int16_t.
o gi_len is ip_len, so it has to be network byteorder.
if_gre.h rev.1.11-1.13
o prototype must not have variable name.
o u_short -> u_int16_t.
o Spell address with two d's.
ip_gre.c rev.1.22-1.29
o KNF - return is not a function.
o The "osrc" variable in gre_mobile_input() is only ever set but not
referenced; remove it.
o correct (false) assumptions on mbuf chain. not sure if it really helps, but
anyways, it is necessary to perform m_pullup.
o correct arg to m_pullup (need to count IP header size as well).
o remove redundant adjustment of m->m_pkthdr.len.
o clear m_flags just for safety.
o tabify.
o u_short -> u_int16_t.
MFC after: 2 weeks
a new bpf_mtap2 routine that does the right thing for an mbuf
and a variable-length chunk of data that should be prepended.
o while we're sweeping the drivers, use u_int32_t uniformly when
when prepending the address family (several places were assuming
sizeof(int) was 4)
o return M_ASSERTVALID to BPF_MTAP* now that all stack-allocated
mbufs have been eliminated; this may better be moved to the bpf
routines
Reviewed by: arch@ and several others
otherwise they are initialized twice when the code is statically
configured in the kernel because the module load method gets
invoked before the user application calls ip_mrouter_init
o add a mutex to synchronize the module init/done operations; this
sort of was done using the value of ip_mroute but X_ip_mrouter_done
sets it to NULL very early on which can lead to a race against
ip_mrouter_init--using the additional mutex means this is safe now
o don't call ip_mrouter_reset from ip_mrouter_init; this now happens
once at module load and X_ip_mrouter_done does the appropriate
cleanup work to insure the data structures are in a consistent
state so that a subsequent init operation inherits good state
Reviewed by: juli
wait, rather than the socket label. This avoids reaching up to
the socket layer during connection close, which requires locking
changes. To do this, introduce MAC Framework entry point
mac_create_mbuf_from_inpcb(), which is called from tcp_twrespond()
instead of calling mac_create_mbuf_from_socket() or
mac_create_mbuf_netlayer(). Introduce MAC Policy entry point
mpo_create_mbuf_from_inpcb(), and implementations for various
policies, which generally just copy label data from the inpcb to
the mbuf. Assert the inpcb lock in the entry point since we
require consistency for the inpcb label reference.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
Before committing the initial tcp_hostcache I changed them from memcpy()
to conform with FreeBSD style without realizing the difference in argument
definition.
This fixes hostcache operation for IPv6 (in general and explicitly IPv6
path mtu discovery) and T/TCP (RFC1644).
Submitted by: Taku YAMAMOTO <taku@cent.saitama-u.ac.jp>
Approved by: re (rwatson)
code is compiled in to support the O_IPSEC operator. Previously no
support was included and ipsec rules were always matching. Note that
we do not return an error when an ipsec rule is added and the kernel
does not have IPsec support compiled in; this is done intentionally
but we may want to revisit this (document this in the man page).
PR: 58899
Submitted by: Bjoern A. Zeeb
Approved by: re (rwatson)
When the hostcache bucket limit is reached the last bucket wasn't
removed from the bucket row but inserted a few lines later at the
bucket row head again. This leads to infinite loop when the same
bucket row is accessed the next time for a lookup/insert or purge
action.
Tested by: imp, Matt Smith
Approved by: re (rwatson)
zeroed. Doing a bzero on the entire struct route is not more
expensive than assigning NULL to ro.ro_rt and bzero of ro.ro_dst.
Reviewed by: sam (mentor)
Approved by: re (scottl)
for ipfw processing w/o an indication the packets were generated
by ipfw--and so should not be processed (this manifested itself
as a LOR.) The flag bit in the mbuf that was used to mark the
packets was not listed in M_COPYFLAGS so if a packet had a header
prepended (as done by IPsec) the flag was lost. Correct this by
defining a new M_PROTO6 flag and use it to mark packets that need
this processing.
Reviewed by: bms
Approved by: re (rwatson)
MFC after: 2 weeks
rtalloc_ign() in in_pcbconnect_setup() before it is filled out.
Otherwise, stack junk would be left in sin_zero, which could
cause host routes to be ignored because they failed the comparison
in rn_match().
This should fix the wrong source address selection for connect() to
127.0.0.1, among other things.
Reviewed by: sam
Approved by: re (rwatson)
the routing table. Move all usage and references in the tcp stack
from the routing table metrics to the tcp hostcache.
It caches measured parameters of past tcp sessions to provide better
initial start values for following connections from or to the same
source or destination. Depending on the network parameters to/from
the remote host this can lead to significant speedups for new tcp
connections after the first one because they inherit and shortcut
the learning curve.
tcp_hostcache is designed for multiple concurrent access in SMP
environments with high contention and is hash indexed by remote
ip address.
It removes significant locking requirements from the tcp stack with
regard to the routing table.
Reviewed by: sam (mentor), bms
Reviewed by: -net, -current, core@kame.net (IPv6 parts)
Approved by: re (scottl)
accordingly. The define is left intact for ABI compatibility
with userland.
This is a pre-step for the introduction of tcp_hostcache. The
network stack remains fully useable with this change.
Reviewed by: sam (mentor), bms
Reviewed by: -net, -current, core@kame.net (IPv6 parts)
Approved by: re (scottl)
the MAC label referenced from 'struct socket' in the IPv4 and
IPv6-based protocols. This permits MAC labels to be checked during
network delivery operations without dereferencing inp->inp_socket
to get to so->so_label, which will eventually avoid our having to
grab the socket lock during delivery at the network layer.
This change introduces 'struct inpcb' as a labeled object to the
MAC Framework, along with the normal circus of entry points:
initialization, creation from socket, destruction, as well as a
delivery access control check.
For most policies, the inpcb label will simply be a cache of the
socket label, so a new protocol switch method is introduced,
pr_sosetlabel() to notify protocols that the socket layer label
has been updated so that the cache can be updated while holding
appropriate locks. Most protocols implement this using
pru_sosetlabel_null(), but IPv4/IPv6 protocols using inpcbs use
the the worker function in_pcbsosetlabel(), which calls into the
MAC Framework to perform a cache update.
Biba, LOMAC, and MLS implement these entry points, as do the stub
policy, and test policy.
Reviewed by: sam, bms
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
do not have mh_nextpkt initialized. Somtimes what's there is "1", and the
ip_input() code pukes trying to m_free() it, rendering divert sockets and
such broken.
This really underscores the need to get rid of MT_TAG.
Reviewed by: rwatson
and remove two unneccessary variable initializations.
Make the introduction comment more clear with regard which parts of
the packet are touched.
Requested by: luigi
complex locking and rework ip_rtaddr() to do its own rtlookup.
Adopt all its callers to this and make ip_output() callable
with NULL rt pointer.
Reviewed by: sam (mentor)
Short description of ip_fastforward:
o adds full direct process-to-completion IPv4 forwarding code
o handles ip fragmentation incl. hw support (ip_flow did not)
o sends icmp needfrag to source if DF is set (ip_flow did not)
o supports ipfw and ipfilter (ip_flow did not)
o supports divert, ipfw fwd and ipfilter nat (ip_flow did not)
o returns anything it can't handle back to normal ip_input
Enable with sysctl -w net.inet.ip.fastforwarding=1
Reviewed by: sam (mentor)
o correct a read-lock assert in in_pcblookup_local that should be
a write-lock assert (since time wait close cleanups may alter state)
Supported by: FreeBSD Foundation
preemption two CPUs can be in the same function at the same time
and clobber each others variables. Remove register declaration
from local variables.
Reviewed by: sam (mentor)
This switch toggles between strict multicast delivery, and traditional
multicast delivery.
The traditional (default) behaviour is to deliver multicast datagrams to all
sockets which are members of that group, regardless of the network interface
where the datagrams were received.
The strict behaviour is to deliver multicast datagrams received on a
particular interface only to sockets whose membership is bound to that
interface.
Note that as a matter of course, multicast consumers specifying INADDR_ANY
for their interface get joined on the interface where the default route
happens to be bound. This switch has no effect if the interface which the
consumer specifies for IP_ADD_MEMBERSHIP is not UP and RUNNING.
The original patch has been cleaned up somewhat from that submitted. It has
been tested on a multihomed machine with multiple QuickTime RTP streams
running over the local switch, which doesn't do IGMP snooping.
PR: kern/58359
Submitted by: William A. Carrel
Reviewed by: rwatson
MFC after: 1 week
in various kernel objects to represent security data, we embed a
(struct label *) pointer, which now references labels allocated using
a UMA zone (mac_label.c). This allows the size and shape of struct
label to be varied without changing the size and shape of these kernel
objects, which become part of the frozen ABI with 5-STABLE. This opens
the door for boot-time selection of the number of label slots, and hence
changes to the bound on the number of simultaneous labeled policies
at boot-time instead of compile-time. This also makes it easier to
embed label references in new objects as required for locking/caching
with fine-grained network stack locking, such as inpcb structures.
This change also moves us further in the direction of hiding the
structure of kernel objects from MAC policy modules, not to mention
dramatically reducing the number of '&' symbols appearing in both the
MAC Framework and MAC policy modules, and improving readability.
While this results in minimal performance change with MAC enabled, it
will observably shrink the size of a number of critical kernel data
structures for the !MAC case, and should have a small (but measurable)
performance benefit (i.e., struct vnode, struct socket) do to memory
conservation and reduced cost of zeroing memory.
NOTE: Users of MAC must recompile their kernel and all MAC modules as a
result of this change. Because this is an API change, third party
MAC modules will also need to be updated to make less use of the '&'
symbol.
Suggestions from: bmilekic
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
it is marked as RTF_UP. This appears to fix a crash that was sometimes
triggered when dhclient(8) tried to send a packet after an interface
had been detatched.
Reviewed by: sam
o pickup Giant in divert_packet to protect sbappendaddr since it
can be entered through MPSAFE callouts or through ip_input when
mpsafenet is 1
o add missing locking on output
o add locking to abort and shutdown
o add a ctlinput handler to invalidate held routing table references
on an ICMP redirect (may not be needed)
Supported by: FreeBSD Foundation
o add assertions in tcp_respond to validate inpcb locking assumptions
o use local variable instead of chasing pointers in tcp_respond
Supported by: FreeBSD Foundation
whether or not the isr needs to hold Giant when running; Giant-less
operation is also controlled by the setting of debug_mpsafenet
o mark all netisr's except NETISR_IP as needing Giant
o add a GIANT_REQUIRED assertion to the top of netisr's that need Giant
o pickup Giant (when debug_mpsafenet is 1) inside ip_input before
calling up with a packet
o change netisr handling so swi_net runs w/o Giant; instead we grab
Giant before invoking handlers based on whether the handler needs Giant
o change netisr handling so that netisr's that are marked MPSAFE may
have multiple instances active at a time
o add netisr statistics for packets dropped because the isr is inactive
Supported by: FreeBSD Foundation
has a LOR between IPFW inpcb locks but I'm committing it now as the
lesser of two evils (the other being unlocked use of in_pcblookup).
Supported by: FreeBSD Foundation
to a routing table entry w/o bumping the reference count or locking
against the entry being free'd. This caused major havoc (for some
reason it appeared most frequently for folks running natd). Fix
is to bump the reference count whenever we copy the route cache
contents into a private copy so the entry cannot be reclaimed out
from under us. This is a short term fix as the forthcoming routing
table changes will eliminate this cache entirely.
Supported by: FreeBSD Foundation
- share policy-on-socket for listening socket.
- don't copy policy-on-socket at all. secpolicy no longer contain
spidx, which saves a lot of memory.
- deep-copy pcb policy if it is an ipsec policy. assign ID field to
all SPD entries. make it possible for racoon to grab SPD entry on
pcb.
- fixed the order of searching SA table for packets.
- fixed to get a security association header. a mode is always needed
to compare them.
- fixed that the incorrect time was set to
sadb_comb_{hard|soft}_usetime.
- disallow port spec for tunnel mode policy (as we don't reassemble).
- an user can define a policy-id.
- clear enc/auth key before freeing.
- fixed that the kernel crashed when key_spdacquire() was called
because key_spdacquire() had been implemented imcopletely.
- preparation for 64bit sequence number.
- maintain ordered list of SA, based on SA id.
- cleanup secasvar management; refcnt is key.c responsibility;
alloc/free is keydb.c responsibility.
- cleanup, avoid double-loop.
- use hash for spi-based lookup.
- mark persistent SP "persistent".
XXX in theory refcnt should do the right thing, however, we have
"spdflush" which would touch all SPs. another solution would be to
de-register persistent SPs from sptree.
- u_short -> u_int16_t
- reduce kernel stack usage by auto variable secasindex.
- clarify function name confusion. ipsec_*_policy ->
ipsec_*_pcbpolicy.
- avoid variable name confusion.
(struct inpcbpolicy *)pcb_sp, spp (struct secpolicy **), sp (struct
secpolicy *)
- count number of ipsec encapsulations on ipsec4_output, so that we
can tell ip_output() how to handle the packet further.
- When the value of the ul_proto is ICMP or ICMPV6, the port field in
"src" of the spidx specifies ICMP type, and the port field in "dst"
of the spidx specifies ICMP code.
- avoid from applying IPsec transport mode to the packets when the
kernel forwards the packets.
Tested by: nork
Obtained from: KAME
header copy made on input path: this is now handled differently.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
directly on the radix tree and does not hold any routing table refernces.
This fixes the reference counting problems that manifested itself as a
panic during unmount of filesystems that were mounted by NFS over an
interface that had been removed.
Supported by: FreeBSD Foundation
previously only considered the send sequence space. Unfortunately,
some OSes (windows) still use a random positive increments scheme for
their syn-ack ISNs, so I must consider receive sequence space as well.
The value of 250000 bytes / second for Microsoft's ISN rate of increase
was determined by testing with an XP machine.
