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
structures, allowing in6_pcbnotify() to lock the pcbinfo and each
inpcb that it notifies of ICMPv6 events. This prevents inpcb
assertions from firing when IPv6 generates and delievers event
notifications for inpcbs.
Reported by: kuriyama
Tested by: kuriyama
or multicast packet, we don't need to acquire the inpcb mutex
unless we are actually using inpcb fields other than the bound port
and address. Since we hold the pcbinfo lock already, these can't
change. Defer acquiring the inpcb mutex until we have a high
chance of a match. This avoids about 120 mutex operations per UDP
broadcast packet received on one of my work systems.
Reviewed by: sam
lock assertions even if IPv6 is compiled into the kernel. Previously,
inclusion of IPv6 and locking assertions would result in a rapid
assertion failure as IPv6 was not properly locking inpcbs.
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
make it fully self-contained.
o ip_reass() now returns a new mbuf with the reassembled packet and ip->ip_len
including the IP header.
o Computation of the delayed checksum is moved into divert_packet().
Reviewed by: silby
Alice is too lazy to write a server application in PF-independent
manner. Therefore she knocks up the server using PF_INET6 only
and allows the IPv6 socket to accept mapped IPv4 as well. An evil
hacker known on IRC as cheshire_cat has an account in the same
system. He starts a process listening on the same port as used
by Alice's server, but in PF_INET. As a consequence, cheshire_cat
will distract all IPv4 traffic supposed to go to Alice's server.
Such sort of port theft was initially enabled by copying the code that
implemented the RFC 2553 semantics on IPv4/6 sockets (see inet6(4)) for
the implied case of the same owner for both connections. After this
change, the above scenario will be impossible. In the same setting,
the user who attempts to start his server last will get EADDRINUSE.
Of course, using IPv4 mapped to IPv6 leads to security complications
in the first place, but there is no reason to make it even more unsafe.
This change doesn't apply to KAME since it affects a FreeBSD-specific
part of the code. It doesn't modify the out-of-box behaviour of the
TCP/IP stack either as long as mapping IPv4 to IPv6 is off by default.
MFC after: 1 month
with the FIN bit set for all segments, if a FIN has already been sent before.
The fix will allow the FIN bit to be set for only the last segment, in case
it has to be retransmitted.
Fix another bug that would have caused snd_nxt to be pulled by len if
there was an error from ip_output. snd_nxt should not be touched
during sack retransmissions.
when inpcb is NULL, this is no longer invalid since jlemon added the
tcp_twstart function... this prevents close "failing" w/ EINVAL when it
really was successful...
Reviewed by: jeremy (NetBSD)
somewhat clearer, but more importantly allows for a consistent naming
scheme for suser_cred flags.
The old name is still defined, but will be removed in a few days (unless I
hear any complaints...)
Discussed with: rwatson, scottl
Requested by: jhb
RTF_BLACKHOLE as well.
To quote the submitter:
The uRPF loose-check implementation by the industry vendors, at least on Cisco
and possibly Juniper, will fail the check if the route of the source address
is pointed to Null0 (on Juniper, discard or reject route). What this means is,
even if uRPF Loose-check finds the route, if the route is pointed to blackhole,
uRPF loose-check must fail. This allows people to utilize uRPF loose-check mode
as a pseudo-packet-firewall without using any manual filtering configuration --
one can simply inject a IGP or BGP prefix with next-hop set to a static route
that directs to null/discard facility. This results in uRPF Loose-check failing
on all packets with source addresses that are within the range of the nullroute.
Submitted by: James Jun <james@towardex.com>
1) data to be sent to the right of snd_recover.
2) send more data then whats in the send buffer.
The fix is to postpone sack retransmit to a subsequent recovery episode
if the current retransmit pointer is beyond snd_recover.
Thanks to Mohan Srinivasan for helping fix the bug.
Submitted by:Daniel Lang
for the SYN|ACK packet and then letting in6_pcbconnect set the
flowlabel later. Arange for the syncache/syncookie code to set and
recall the flow label so that the flowlabel used for the SYN|ACK
is consistent. This is done by using some of the cookie (when tcp
cookies are enabeled) and by stashing the flowlabel in syncache.
Tested and Discovered by: Orla McGann <orly@cnri.dit.ie>
Approved by: ume, silby
MFC after: 1 month
icmp_error() packets. While here retire PACKET_TAG_PF_GENERATED (which
served the same purpose) and use M_SKIP_FIREWALL in pf as well. This should
speed up things a bit as we get rid of the tag allocations.
Discussed with: juli
using M_PROTO6 and possibly shooting someone's foot, as well as allowing the
firewall to be used in multiple passes, or with a packet classifier frontend,
that may need to explicitly allow a certain packet. Presently this is handled
in the ipfw_chk code as before, though I have run with it moved to upper
layers, and possibly it should apply to ipfilter and pf as well, though this
has not been investigated.
Discussed with: luigi, rwatson
for unknown events.
A number of modules return EINVAL in this instance, and I have left
those alone for now and instead taught MOD_QUIESCE to accept this
as "didn't do anything".
bootp -> BOOTP
bootp.nfsroot -> BOOTP_NFSROOT
bootp.nfsv3 -> BOOTP_NFSV3
bootp.compat -> BOOTP_COMPAT
bootp.wired_to -> BOOTP_WIRED_TO
- i.e. back out the previous commit. It's already possible to
pxeboot(8) with a GENERIC kernel.
Pointed out by: dwmalone
BOOTP -> bootp
BOOTP_NFSROOT -> bootp.nfsroot
BOOTP_NFSV3 -> bootp.nfsv3
BOOTP_COMPAT -> bootp.compat
BOOTP_WIRED_TO -> bootp.wired_to
This lets you PXE boot with a GENERIC kernel by putting this sort of thing
in loader.conf:
bootp="YES"
bootp.nfsroot="YES"
bootp.nfsv3="YES"
bootp.wired_to="bge1"
or even setting the variables manually from the OK prompt.
{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.
Fix this problem by separating out the SACK and the newreno cases. Also, check
if we are in FASTRECOVERY for the sack case and if so, turn off dupacks.
Fix an issue where the congestion window was not being incremented by ssthresh.
Thanks to Mohan Srinivasan for finding this problem.
associated with performing a wakeup on the socket buffer:
- When performing an sbappend*() followed by a so[rw]wakeup(), explicitly
acquire the socket buffer lock and use the _locked() variants of both
calls. Note that the _locked() sowakeup() versions unlock the mutex on
return. This is done in uipc_send(), divert_packet(), mroute
socket_send(), raw_append(), tcp_reass(), tcp_input(), and udp_append().
- When the socket buffer lock is dropped before a sowakeup(), remove the
explicit unlock and use the _locked() sowakeup() variant. This is done
in soisdisconnecting(), soisdisconnected() when setting the can't send/
receive flags and dropping data, and in uipc_rcvd() which adjusting
back-pressure on the sockets.
For UNIX domain sockets running mpsafe with a contention-intensive SMP
mysql benchmark, this results in a 1.6% query rate improvement due to
reduce mutex costs.
locking in tcp_input() for TCP packets with urgent data pointers to
hold the socket buffer lock across testing and updating oobmark
from just protecting sb_state.
Update socket locking annotations
Giant if debug.mpsafenet=0, as any points that require synchronization
in the SMPng world also required it in the Giant-world:
- inpcb locks (including IPv6)
- inpcbinfo locks (including IPv6)
- dummynet subsystem lock
- ipfw2 subsystem lock
the socket buffer having its limits adjusted. sbreserve() now acquires
the lock before calling sbreserve_locked(). In soreserve(), acquire
socket buffer locks across read-modify-writes of socket buffer fields,
and calls into sbreserve/sbrelease; make sure to acquire in keeping
with the socket buffer lock order. In tcp_mss(), acquire the socket
buffer lock in the calling context so that we have atomic read-modify
-write on buffer sizes.
originated on RELENG_4 and was ported to -CURRENT.
The scoreboarding code was obtained from OpenBSD, and many
of the remaining changes were inspired by OpenBSD, but not
taken directly from there.
You can enable/disable sack using net.inet.tcp.do_sack. You can
also limit the number of sack holes that all senders can have in
the scoreboard with net.inet.tcp.sackhole_limit.
Reviewed by: gnn
Obtained from: Yahoo! (Mohan Srinivasan, Jayanth Vijayaraghavan)
ip_ctloutput(), as it may need to perform blocking memory allocations.
This also improves consistency with locking relative to other points
that call into ip_ctloutput().
Bumped into by: Grover Lines <grover@ceribus.net>
was received on a broadcast address on the input path. Under certain
circumstances this could result in a panic, notably for locally-generated
packets which do not have m_pkthdr.rcvif set.
This is a similar situation to that which is solved by
src/sys/netinet/ip_icmp.c rev 1.66.
PR: kern/52935
encapsulated within an IPv6 datagram, do not abuse the 'ipov' pointer
when registering trace records. 'ipov' is specific to IPv4, and
will therefore be uninitialized.
[This fandango is only necessary in the first place because of our
host-byte-order IP field pessimization.]
PR: kern/60856
Submitted by: Galois Zheng
unless the segment really contains the last of the data for the stream.
PR: kern/34619
Obtained from: OpenBSD (tcp_output.c rev 1.47)
Noticed by: Joseph Ishac
Reviewed by: George Neville-Neil
Version 3.5 brings:
- Atomic commits of ruleset changes (reduce the chance of ending up in an
inconsistent state).
- A 30% reduction in the size of state table entries.
- Source-tracking (limit number of clients and states per client).
- Sticky-address (the flexibility of round-robin with the benefits of
source-hash).
- Significant improvements to interface handling.
- and many more ...
- Remove pflog and pfsync modules. Things will change in such a fashion
that there will be one module with pf+pflog that can be loaded into
GENERIC without problems (which is what most people want). pfsync is no
longer possible as a module.
- Add multicast address for in-kernel multicast pfsync protocol. Protocol
glue will follow once the import is done.
- Add one more mbuf tag
do not pick up the first local ip address for the source
ip address, return ENETUNREACH instead.
Submitted by: Gleb Smirnoff
Reviewed by: -current (silence)
mode tunnel, take the per-route MTU into account, *if* and *only if* it
is non-zero (as found in struct rt_metrics/rt_metrics_lite).
PR: kern/42727
Obtained from: NetBSD (ip_input.c rev 1.151)
fixes the problem of UDP sockets getting wedged in a connected state (and
bound to their destination) under heavy load.
Temporary bind/connect should probably be deleted in future
as an optimization, as described in "A Faster UDP" [Partridge/Pink 1993].
Notes:
- INP_LOCK() is already held in udp_output(). The connection is in effect
happening at a layer lower than the socket layer, therefore in theory
socket locking should not be needed.
- Inlining the in_pcbdisconnect() operation buys us nothing (in the case
of the current state of the code), as laddr is not part of the
inpcb hash or the udbinfo hash. Therefore there should be no need
to rehash after restoring laddr in the error case (this was a
concern of the original author of the patch).
PR: kern/41765
Requested by: gnn
Submitted by: Jinmei Tatuya (with cleanups)
Tested by: spray(8)
flags relating to several aspects of socket functionality. This change
breaks out several bits relating to send and receive operation into a
new per-socket buffer field, sb_state, in order to facilitate locking.
This is required because, in order to provide more granular locking of
sockets, different state fields have different locking properties. The
following fields are moved to sb_state:
SS_CANTRCVMORE (so_state)
SS_CANTSENDMORE (so_state)
SS_RCVATMARK (so_state)
Rename respectively to:
SBS_CANTRCVMORE (so_rcv.sb_state)
SBS_CANTSENDMORE (so_snd.sb_state)
SBS_RCVATMARK (so_rcv.sb_state)
This facilitates locking by isolating fields to be located with other
identically locked fields, and permits greater granularity in socket
locking by avoiding storing fields with different locking semantics in
the same short (avoiding locking conflicts). In the future, we may
wish to coallesce sb_state and sb_flags; for the time being I leave
them separate and there is no additional memory overhead due to the
packing/alignment of shorts in the socket buffer structure.
your (network) modules as well as any userland that might make sense of
sizeof(struct ifnet).
This does not change the queueing yet. These changes will follow in a
seperate commit. Same with the driver changes, which need case by case
evaluation.
__FreeBSD_version bump will follow.
Tested-by: (i386)LINT
conform to the rfc2734 and rfc3146 standard for IP over firewire and
should eventually supercede the fwe driver. Right now the broadcast
channel number is hardwired and we don't support MCAP for multicast
channel allocation - more infrastructure is required in the firewire
code itself to fix these problems.
SOCK_LOCK(so):
- Hold socket lock over calls to MAC entry points reading or
manipulating socket labels.
- Assert socket lock in MAC entry point implementations.
- When externalizing the socket label, first make a thread-local
copy while holding the socket lock, then release the socket lock
to externalize to userspace.
reference count:
- Assert SOCK_LOCK(so) macros that directly manipulate so_count:
soref(), sorele().
- Assert SOCK_LOCK(so) in macros/functions that rely on the state of
so_count: sofree(), sotryfree().
- Acquire SOCK_LOCK(so) before calling these functions or macros in
various contexts in the stack, both at the socket and protocol
layers.
- In some cases, perform soisdisconnected() before sotryfree(), as
this could result in frobbing of a non-present socket if
sotryfree() actually frees the socket.
- Note that sofree()/sotryfree() will release the socket lock even if
they don't free the socket.
Submitted by: sam
Sponsored by: FreeBSD Foundation
Obtained from: BSD/OS
ruleset, the pcb is looked up once per ipfw_chk() activation.
This is done by extracting the required information out of the PCB
and caching it to the ipfw_chk() stack. This should greatly reduce
PCB looking contention and speed up the processing of UID/GID based
firewall rules (especially with large UID/GID rulesets).
Some very basic benchmarks were taken which compares the number
of in_pcblookup_hash(9) activations to the number of firewall
rules containing UID/GID based contraints before and after this patch.
The results can be viewed here:
o http://people.freebsd.org/~csjp/ip_fw_pcb.png
Reviewed by: andre, luigi, rwatson
Approved by: bmilekic (mentor)
versions of various routers seen:
- Introduce igmp_mtx.
- Protect global variable 'router_info_head' and list fields
in struct router_info with this mutex, as well as
igmp_timers_are_running.
- find_rti() asserts that the caller acquires igmp_mtx.
- Annotate a failure to check the return value of
MALLOC(..., M_NOWAIT).
that m_prepend() is not called with possibility to wait while the
pcb lock is held. What still needs revisiting is whether the
ripcbinfo lock is really required here.
Discussed with: rwatson
process is a non-prison root. The security.jail.allow_raw_sockets
sysctl variable is disabled by default, however if the user enables
raw sockets in prisons, prison-root should not be able to interact
with firewall rule sets.
Approved by: rwatson, bmilekic (mentor)
unless it's in the closed or listening state (remote address
== INADDR_ANY).
If a TCP inpcb is in any other state, it's impossible to steal
its local port or use it for port theft. And if there are
both closed/listening and connected TCP inpcbs on the same
localIP:port couple, the call to in_pcblookup_local() will
find the former due to the design of that function.
No objections raised in: -net, -arch
MFC after: 1 month
of IP options.
net.inet.ip.process_options=0 Ignore IP options and pass packets unmodified.
net.inet.ip.process_options=1 Process all IP options (default).
net.inet.ip.process_options=2 Reject all packets with IP options with ICMP
filter prohibited message.
This sysctl affects packets destined for the local host as well as those
only transiting through the host (routing).
IP options do not have any legitimate purpose anymore and are only used
to circumvent firewalls or to exploit certain behaviours or bugs in TCP/IP
stacks.
Reviewed by: sam (mentor)
labeling new mbufs created from sockets/inpcbs in IPv4. This helps avoid
the need for socket layer locking in the lower level network paths
where inpcb locks are already frequently held where needed. In
particular:
- Use the inpcb for label instead of socket in raw_append().
- Use the inpcb for label instead of socket in tcp_output().
- Use the inpcb for label instead of socket in tcp_respond().
- Use the inpcb for label instead of socket in tcp_twrespond().
- Use the inpcb for label instead of socket in syncache_respond().
While here, modify tcp_respond() to avoid assigning NULL to a stack
variable and centralize assertions about the inpcb when inp is
assigned.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, McAfee Research
o New function ip_findroute() to reduce code duplication for the
route lookup cases. (luigi)
o Store ip_len in host byte order on the stack instead of using
it via indirection from the mbuf. This allows to defer the host
byte conversion to a later point and makes a quicker fallback to
normal ip_input() processing. (luigi)
o Check if route is dampned with RTF_REJECT flag and drop packet
already here when ARP is unable to resolve destination address.
An ICMP unreachable is sent to inform the sender.
o Check if interface output queue is full and drop packet already
here. No ICMP notification is sent because signalling source quench
is depreciated.
o Check if media_state is down (used for ethernet type interfaces)
and drop the packet already here. An ICMP unreachable is sent to
inform the sender.
o Do not account sent packets to the interface address counters. They
are only for packets with that 'ia' as source address.
o Update and clarify some comments.
Submitted by: luigi (most of it)
uncommitted):
Rename ip_claim_next_hop() to m_claim_next_hop(), give it an extra arg
(the type of tag to claim) and push it out of ip_var.h into mbuf.h
alongside all of the other macros that work ok mbuf's and tag's.
jail, which is less restrictive but allows for more flexible
jail usage (for those who are willing to make the sacrifice).
The default is off, but allowing raw sockets within jails can
now be accomplished by tuning security.jail.allow_raw_sockets
to 1.
Turning this on will allow you to use things like ping(8)
or traceroute(8) from within a jail.
The patch being committed is not identical to the patch
in the PR. The committed version is more friendly to
APIs which pjd is working on, so it should integrate
into his work quite nicely. This change has also been
presented and addressed on the freebsd-hackers mailing
list.
Submitted by: Christian S.J. Peron <maneo@bsdpro.com>
PR: kern/65800
possible while maintaining compatibility with the widest range of TCP stacks.
The algorithm is as follows:
---
For connections in the ESTABLISHED state, only resets with
sequence numbers exactly matching last_ack_sent will cause a reset,
all other segments will be silently dropped.
For connections in all other states, a reset anywhere in the window
will cause the connection to be reset. All other segments will be
silently dropped.
---
The necessity of accepting all in-window resets was discovered
by jayanth and jlemon, both of whom have seen TCP stacks that
will respond to FIN-ACK packets with resets not meeting the
strict last_ack_sent check.
Idea by: Darren Reed
Reviewed by: truckman, jlemon, others(?)
1. rt_check() cleanup:
rt_check() is only necessary for some address families to gain access
to the corresponding arp entry, so call it only in/near the *resolve()
routines where it is actually used -- at the moment this is
arpresolve(), nd6_storelladdr() (the call is embedded here),
and atmresolve() (the call is just before atmresolve to reduce
the number of changes).
This change will make it a lot easier to decouple the arp table
from the routing table.
There is an extra call to rt_check() in if_iso88025subr.c to
determine the routing info length. I have left it alone for
the time being.
The interface of arpresolve() and nd6_storelladdr() now changes slightly:
+ the 'rtentry' parameter (really a hint from the upper level layer)
is now passed unchanged from *_output(), so it becomes the route
to the final destination and not to the gateway.
+ the routines will return 0 if resolution is possible, non-zero
otherwise.
+ arpresolve() returns EWOULDBLOCK in case the mbuf is being held
waiting for an arp reply -- in this case the error code is masked
in the caller so the upper layer protocol will not see a failure.
2. arpcom untangling
Where possible, use 'struct ifnet' instead of 'struct arpcom' variables,
and use the IFP2AC macro to access arpcom fields.
This mostly affects the netatalk code.
=== Detailed changes: ===
net/if_arcsubr.c
rt_check() cleanup, remove a useless variable
net/if_atmsubr.c
rt_check() cleanup
net/if_ethersubr.c
rt_check() cleanup, arpcom untangling
net/if_fddisubr.c
rt_check() cleanup, arpcom untangling
net/if_iso88025subr.c
rt_check() cleanup
netatalk/aarp.c
arpcom untangling, remove a block of duplicated code
netatalk/at_extern.h
arpcom untangling
netinet/if_ether.c
rt_check() cleanup (change arpresolve)
netinet6/nd6.c
rt_check() cleanup (change nd6_storelladdr)
from tcp_hostcache would have overridden a (now) lower MTU of
an interface or route that changed since first PMTU discovery.
The bug would have caused TCP to redo the PMTU discovery when
not strictly necessary.
Make a comment about already pre-initialized default values
more clear.
Reviewed by: sam
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
implementation taken directly from OpenBSD.
I've resisted committing this for quite some time because of concern over
TIME_WAIT recycling breakage (sequential allocation ensures that there is a
long time before ports are recycled), but recent testing has shown me that
my fears were unwarranted.
TIME_WAIT recycling cases I was able to generate with http testing tools.
In short, as the old algorithm relied on ticks to create the time offset
component of an ISN, two connections with the exact same host, port pair
that were generated between timer ticks would have the exact same sequence
number. As a result, the second connection would fail to pass the TIME_WAIT
check on the server side, and the SYN would never be acknowledged.
I've "fixed" this by adding random positive increments to the time component
between clock ticks so that ISNs will *always* be increasing, no matter how
quickly the port is recycled.
Except in such contrived benchmarking situations, this problem should never
come up in normal usage... until networks get faster.
No MFC planned, 4.x is missing other optimizations that are needed to even
create the situation in which such quick port recycling will occur.
in favour of rtalloc_ign(), which is what would end up being called
anyways.
There are 25 more instances of rtalloc() in net*/ and
about 10 instances of rtalloc_ign()
we convert ip_len into a network byte order; in_delayed_cksum() still
expects it in host byte order.
The symtom was the ``in_cksum_skip: out of data by %d'' complaints
from the kernel.
To add to the previous commit log. These fixes make tcpdump(1) happy
by not complaining about UDP/TCP checksum being bad for looped back
IP multicast when multicast router is deactivated.
Reported by: Vsevolod Lobko
to implement this mistake.
Fixed some nearby style bugs (initialization in declaration, misformatting
of this initialization, missing blank line after the declaration, and
comparision of the non-boolean result of the initialization with 0 using
"!". In KNF, "!" is not even used to compare booleans with 0).
It was fixed by moving problemetic checks, as well as checks that
doesn't need locking before locks are acquired.
Submitted by: Ryan Sommers <ryans@gamersimpact.com>
In co-operation with: cperciva, maxim, mlaier, sam
Tested by: submitter (previous patch), me (current patch)
Reviewed by: cperciva, mlaier (previous patch), sam (current patch)
Approved by: sam
Dedicated to: enough!
+ struct ifnet: remove unused fields, move ipv6-related field close
to each other, add a pointer to l3<->l2 translation tables (arp,nd6,
etc.) for future use.
+ struct route: remove an unused field, move close to each
other some fields that might likely go away in the future
Previously, Giant would be grabbed at entry to the IP local delivery code
when debug.mpsafenet was set to true, as that implied Giant wouldn't be
grabbed in the driver path. Now, we will use this primitive to
conditionally grab Giant in the event the entire network stack isn't
running MPSAFE (debug.mpsafenet == 0).
Compute the payload checksum for a locally originated IP multicast where
God intended, in ip_mloopback(), rather than doing it in ip_output() and
only when multicast router is active. This is more correct as we do not
fool ip_input() that the packet has the correct payload checksum when in
fact it does not (when multicast router is inactive). This is also more
efficient if we don't join the multicast group we send to, thus allowing
the hardware to checksum the payload.
- Add gre_mtx to protect global softc list.
- Hold gre_mtx over various list operations (insert, delete).
- Centralize if_gre interface teardown in gre_destroy(), and call this
from modevent unload and gre_clone_destroy().
- Export gre_mtx to ip_gre.c, which walks the gre list to look up gre
interfaces during encapsulation. Add a wonking comment on how we need
some sort of drain/reference count mechanism to keep gre references
alive while in use and simultaneous destroy.
This commit does not lockdown softc data, which follows in a future
commit.
- Add encapmtx to protect ip_encap.c global variables (encapsulation
list).
- Unifdef #ifdef 0 pieces of encap_init() which was (and now really
is) basically a no-op.
- Lock encapmtx when walking encaptab, modifying it, comparing
entries, etc.
- Remove spl's.
Note that currently there's no facilite to make sure outstanding
use of encapsulation methods on a table entry have drained bfore
we allow a table entry to be removed. As such, it's currently the
caller's responsibility to make sure that draining takes place.
Reviewed by: mlaier
ifp is now passed explicitly to ether_demux; no need to look it up again.
Make mtag a global var in ip_input.
Noticed by: rwatson
Approved by: bms(mentor)
to NET_UNLOCK_GIANT(). While they are used in similar ways, the
semantics are quite different -- NET_LOCK_GIANT() and NET_UNLOCK_GIANT()
directly wrap mutex lock and unlock operations, whereas drop/pickup
special case the handling of Giant recursion. Add a comment saying
as much.
Add NET_ASSERT_GIANT(), which conditionally asserts Giant based
on the value of debug_mpsafenet.
This enables pf to track dynamic address changes on interfaces (dailup) with
the "on (<ifname>)"-syntax. This also brings hooks in anticipation of
tracking cloned interfaces, which will be in future versions of pf.
Approved by: bms(mentor)
pf/pflog/pfsync as modules. Do not list them in NOTES or modules/Makefile
(i.e. do not connect it to any (automatic) builds - yet).
Approved by: bms(mentor)
the syscall arguments and does the suser() permission check, and
kern_mlock(), which does the resource limit checking and calls
vm_map_wire(). Split munlock() in a similar way.
Enable the RLIMIT_MEMLOCK checking code in kern_mlock().
Replace calls to vslock() and vsunlock() in the sysctl code with
calls to kern_mlock() and kern_munlock() so that the sysctl code
will obey the wired memory limits.
Nuke the vslock() and vsunlock() implementations, which are no
longer used.
Add a member to struct sysctl_req to track the amount of memory
that is wired to handle the request.
Modify sysctl_wire_old_buffer() to return an error if its call to
kern_mlock() fails. Only wire the minimum of the length specified
in the sysctl request and the length specified in its argument list.
It is recommended that sysctl handlers that use sysctl_wire_old_buffer()
should specify reasonable estimates for the amount of data they
want to return so that only the minimum amount of memory is wired
no matter what length has been specified by the request.
Modify the callers of sysctl_wire_old_buffer() to look for the
error return.
Modify sysctl_old_user to obey the wired buffer length and clean up
its implementation.
Reviewed by: bms
increased <netinet/tcp_var>'s already large set of prerequisites, and
this was handled badly. Just don't declare the complete syncache struct
unless <netinet/pcb.h> is included before <netinet/tcp_var.h>.
Approved by: jlemon (years ago, for a more invasive fix)
amount of segments it will hold.
The following tuneables and sysctls control the behaviour of the tcp
segment reassembly queue:
net.inet.tcp.reass.maxsegments (loader tuneable)
specifies the maximum number of segments all tcp reassemly queues can
hold (defaults to 1/16 of nmbclusters).
net.inet.tcp.reass.maxqlen
specifies the maximum number of segments any individual tcp session queue
can hold (defaults to 48).
net.inet.tcp.reass.cursegments (readonly)
counts the number of segments currently in all reassembly queues.
net.inet.tcp.reass.overflows (readonly)
counts how often either the global or local queue limit has been reached.
Tested by: bms, silby
Reviewed by: bms, silby
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
