from Mac OS X Leopard--rationalize naming for entry points to
the following general forms:
mac_<object>_<method/action>
mac_<object>_check_<method/action>
The previous naming scheme was inconsistent and mostly
reversed from the new scheme. Also, make object types more
consistent and remove spaces from object types that contain
multiple parts ("posix_sem" -> "posixsem") to make mechanical
parsing easier. Introduce a new "netinet" object type for
certain IPv4/IPv6-related methods. Also simplify, slightly,
some entry point names.
All MAC policy modules will need to be recompiled, and modules
not updates as part of this commit will need to be modified to
conform to the new KPI.
Sponsored by: SPARTA (original patches against Mac OS X)
Obtained from: TrustedBSD Project, Apple Computer
TCP: [X.X.X.X]:X to [X.X.X.X]:X tcpflags 0x18<PUSH,ACK>; tcp_do_segment: FIN_WAIT_2: Received data after socket was closed, sending RST and removing tcpcb
So that it also includes how many bytes of data were received. It now looks
like this:
TCP: [X.X.X.X]:X to [X.X.X.X]:X tcpflags 0x18<PUSH,ACK>; tcp_do_segment: FIN_WAIT_2: Received X bytes of data after socket was closed, sending RST and removing tcpcb
Approved by: re (gnn)
jumping to dropunlock to avoid a panic. While here move the calls to
ipsec4_in_reject() and ipsec6_in_reject() so they are after we obtain
the lock on inp.
Original patch to avoid panic: pjd
Review of locking adjustments: gnn, sam
Approved by: re (rwatson)
<netinet/tcp_fsm.h> is included into any compilation unit that needs
tcpstates[]. Also remove incorrect extern declarations and TCPDEBUG
conditionals. This allows kernels both with and without TCPDEBUG to
build, and unbreaks the tinderbox.
Approved by: re (rwatson)
sys.net.inet.tcp.log_debug = 1
It defaults to enabled for the moment and is to be turned off for
the next release like other diagnostics from development branches.
It is important to note that sysctl sys.net.inet.tcp.log_in_vain
uses the same logging function as log_debug. Enabling of the former
also causes the latter to engage, but not vice versa.
Use consistent terminology in tcp log messages:
"ignored" means a segment contains invalid flags/information and
is dropped without changing state or issuing a reply.
"rejected" means a segments contains invalid flags/information but
is causing a reply (usually RST) and may cause a state change.
Approved by: re (rwatson)
syncache_rst().
o Fix tests for flag combinations of RST and SYN, ACK, FIN. Before
a RST for a connection in syncache did not properly free the entry.
o Add more detailed logging.
Approved by: re (rwatson)
This commit includes only the kernel files, the rest of the files
will follow in a second commit.
Reviewed by: bz
Approved by: re
Supported by: Secure Computing
be called with an incorrect segment end value. tcp_reass() may
trim segments when they overlap with already existing ones in the
reassembly queue. Instead of saving the segment end value before
the call to tcp_reass() compute it on the fly based on the effective
segment length afterwards.
This bug was not really problematic as no information got lost and
the eventual SACK information computation was correct nontheless.
MFC after: 1 week
and simplify handling of the send/receive window scaling. No
change in effective behavour.
RFC1323 requires the window field in a SYN (i.e., a <SYN> or
<SYN,ACK>) segment itself never be scaled.
Noticed by: yar
in tcp_input():
o tighten the checks on allowed TCP flags to be RFC793 and
tcp-secure conform
o log check failures to syslog at LOG_DEBUG level
o rearrange the code flow to be easier to follow
o add KASSERTs to validate assumptions of the code flow
Add sysctl net.inet.tcp.syncache.rst_on_sock_fail defaulting to enable
that controls the behavior on socket creation failure for a otherwise
successful 3-way handshake. The socket creation can fail due to global
memory shortage, listen queue limits and file descriptor limits. The
sysctl allows to chose between two options to deal with this. One is
to send a reset to the other endpoint to notify it about the failure
(default). The other one is to ignore and treat the failure as a
transient error and have the other endpoint retransmit for another try.
Reviewed by: rwatson (in general)
for use thoughout the tcp subsystem.
It is IPv4 and IPv6 aware creates a line in the following format:
"TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags <RST>"
A "\n" is not included at the end. The caller is supposed to add
further information after the standard tcp log header.
The function returns a NUL terminated string which the caller has
to free(s, M_TCPLOG) after use. All memory allocation is done
with M_NOWAIT and the return value may be NULL in memory shortage
situations.
Either struct in_conninfo || (struct tcphdr && (struct ip || struct
ip6_hdr) have to be supplied.
Due to ip[6].h header inclusion limitations and ordering issues the
struct ip and struct ip6_hdr parameters have to be casted and passed
as void * pointers.
tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
void *ip6hdr)
Usage example:
struct ip *ip;
char *tcplog;
if (tcplog = tcp_log_addrs(NULL, th, (void *)ip, NULL)) {
log(LOG_DEBUG, "%s; %s: Connection attempt to closed port\n",
tcplog, __func__);
free(s, M_TCPLOG);
}
other than repo copied tcp_subr.c into tcp_timewait.c#1.284:
tcp_input.c#1.350 tcp_timewait() -> tcp_twcheck()
tcp_timer.c#1.92 tcp_timer_2msl_reset() -> tcp_tw_2msl_reset()
tcp_timer.c#1.92 tcp_timer_2msl_stop() -> tcp_tw_2msl_stop()
tcp_timer.c#1.92 tcp_timer_2msl_tw() -> tcp_tw_2msl_scan()
This is a mechanical move with appropriate renames and making
them static if used only locally.
The tcp_tw_2msl_scan() cleanup function is still run from the
tcp_slowtimo() in tcp_timer.c.
functions from their origininal place to their own files.
TCP Reassembly from tcp_input.c -> tcp_reass.c
TCP Timewait from tcp_subr.c -> tcp_timewait.c
and change it to a void function.
We use a compressed structure for TCPS_TIME_WAIT to save memory. Any late
late segments arriving for such a connection is handled directly in the TW
code.
from the incoming SYN handling section of tcp_input().
Enforcement of the accept queue limits is done by sonewconn() after the
3WHS is completed. It is not necessary to have an earlier check before a
connection request enters the SYN cache awaiting the full handshake. It
rather limits the effectiveness of the syncache by preventing legit and
illegit connections from entering it and having them shaken out before we
hit the real limit which may have vanished by then.
Change return value of syncache_add() to void. No status communication
is required.
when the ACK is invalid and doesn't belong to any registered connection,
either in syncache or through SYN cookies. True but a NULL struct socket
is returned when the 3WHS completed but the socket could not be created
due to insufficient resources or limits reached.
For both cases an RST is sent back in tcp_input().
A logic error leading to a panic is fixed where syncache_expand() would
free the mbuf on socket allocation failure but tcp_input() later supplies
it to tcp_dropwithreset() to issue a RST to the peer.
Reported by: kris (the panic)
directly to a merged model where only one callout, the next to fire,
is registered.
Instead of callout_reset(9) and callout_stop(9) the new function
tcp_timer_activate() is used which then internally manages the callout.
The single new callout is a mutex callout on inpcb simplifying the
locking a bit.
tcp_timer() is the called function which handles all race conditions
in one place and then dispatches the individual timer functions.
Reviewed by: rwatson (earlier version)
tcp_input() to syncache_socket() where it belongs and the majority
of it already happens.
The "tp->snd_up = tp->snd_una" is removed as it is done with the
tcp_sendseqinit() macro a few lines earlier.
o tcp_input() now handles TCP segment sanity checks and preparations
including the INPCB lookup and syncache.
o tcp_do_segment() handles all data and ACK processing and is IPv4/v6
agnostic.
Change all KASSERT() messages to ("%s: ", __func__).
The changes in this commit are primarily of mechanical nature and no
functional changes besides the function split are made.
Discussed with: rwatson
and syncache_respond() into its own generic function tcp_addoptions().
tcp_addoptions() is alignment agnostic and does optimal packing in all cases.
In struct tcpopt rename to_requested_s_scale to just to_wscale.
Add a comment with quote from RFC1323: "The Window field in a SYN (i.e.,
a <SYN> or <SYN,ACK>) segment itself is never scaled."
Reviewed by: silby, mohans, julian
Sponsored by: TCP/IP Optimization Fundraise 2005
in the field. In one situation, one end of the TCP connection sends
a back-to-back RST packet, with delayed ack, the last_ack_sent variable
has not been update yet. When tcp_insecure_rst is turned off, the code
treats the RST as invalid because last_ack_sent instead of rcv_nxt is
compared against th_seq. Apparently there is some kind of firewall that
sits in between the two ends and that RST packet is the only RST
packet received. With short lived HTTP connections, the symptom is
a large accumulation of connections over a short period of time .
The +/-(1) factor is to take care of implementations out there that
generate RST packets with these types of sequence numbers. This
behavior has also been observed in live environments.
Reviewed by: silby, Mike Karels
MFC after: 1 week
potential issues where the peer does not close, potentially leaving
thousands of connections in FIN_WAIT_2. This is controlled by a new sysctl
fast_finwait2_recycle, which is disabled by default.
Reviewed by: gnn, silby.
Normally the socket buffers are static (either derived from global
defaults or set with setsockopt) and do not adapt to real network
conditions. Two things happen: a) your socket buffers are too small
and you can't reach the full potential of the network between both
hosts; b) your socket buffers are too big and you waste a lot of
kernel memory for data just sitting around.
With automatic TCP send and receive socket buffers we can start with a
small buffer and quickly grow it in parallel with the TCP congestion
window to match real network conditions.
FreeBSD has a default 32K send socket buffer. This supports a maximal
transfer rate of only slightly more than 2Mbit/s on a 100ms RTT
trans-continental link. Or at 200ms just above 1Mbit/s. With TCP send
buffer auto scaling and the default values below it supports 20Mbit/s
at 100ms and 10Mbit/s at 200ms. That's an improvement of factor 10, or
1000%. For the receive side it looks slightly better with a default of
64K buffer size.
New sysctls are:
net.inet.tcp.sendbuf_auto=1 (enabled)
net.inet.tcp.sendbuf_inc=8192 (8K, step size)
net.inet.tcp.sendbuf_max=262144 (256K, growth limit)
net.inet.tcp.recvbuf_auto=1 (enabled)
net.inet.tcp.recvbuf_inc=16384 (16K, step size)
net.inet.tcp.recvbuf_max=262144 (256K, growth limit)
Tested by: many (on HEAD and RELENG_6)
Approved by: re
MFC after: 1 month
In ip6_sprintf no longer use and return one of eight static buffers
for printing/logging ipv6 addresses.
The caller now has to hand in a sufficiently large buffer as first
argument.
begun with a repo-copy of mac.h to mac_framework.h. sys/mac.h now
contains the userspace and user<->kernel API and definitions, with all
in-kernel interfaces moved to mac_framework.h, which is now included
across most of the kernel instead.
This change is the first step in a larger cleanup and sweep of MAC
Framework interfaces in the kernel, and will not be MFC'd.
Obtained from: TrustedBSD Project
Sponsored by: SPARTA
the header field for possible later IPSEC SPD lookup, even
when the kernel is built without 'options INET6'.
PR: kern/57760
MFC after: 1 week
Submitted by: Joachim Schueth
functionality:
- Remove a rwlock aquisition/release per generated syncookie. Locking
is now integrated with the bucket row locking of syncache itself and
syncookies no longer add any additional lock overhead.
- Syncookie secrets are different for and stored per syncache buck row.
Secrets expire after 16 seconds and are reseeded on-demand.
- The computational overhead for syncookie generation and verification
is one MD5 hash computation as before.
- Syncache can be turned off and run with syncookies only by setting the
sysctl net.inet.tcp.syncookies_only=1.
This implementation extends the orginal idea and first implementation
of FreeBSD by using not only the initial sequence number field to store
information but also the timestamp field if present. This way we can
keep track of the entire state we need to know to recreate the session in
its original form. Almost all TCP speakers implement RFC1323 timestamps
these days. For those that do not we still have to live with the known
shortcomings of the ISN only SYN cookies. The use of the timestamp field
causes the timestamps to be randomized if syncookies are enabled.
The idea of SYN cookies is to encode and include all necessary information
about the connection setup state within the SYN-ACK we send back and thus
to get along without keeping any local state until the ACK to the SYN-ACK
arrives (if ever). Everything we need to know should be available from
the information we encoded in the SYN-ACK.
A detailed description of the inner working of the syncookies mechanism
is included in the comments in tcp_syncache.c.
Reviewed by: silby (slightly earlier version)
Sponsored by: TCP/IP Optimization Fundraise 2005
timeouts for TCP and T/TCP connections in the TIME_WAIT
state, and we had two separate timed wait queues for them.
Now that is has gone, the timeout is always 2*MSL again,
and there is no reason to keep two queues (the first was
unused anyway!).
Also, reimplement the remaining queue using a TAILQ (it
was technically impossible before, with two queues).
o add IFCAP_TSO[46] for drivers to announce this capability for IPv4 and IPv6
o add CSUM_TSO flag to mbuf pkthdr csum_flags field
o add tso_segsz field to mbuf pkthdr
o enhance ip_output() packet length check to allow for large TSO packets
o extend tcp_maxmtu[46]() with a flag pointer to pass interface capabilities
o adjust all callers of tcp_maxmtu[46]() accordingly
Discussed on: -current, -net
Sponsored by: TCP/IP Optimization Fundraise 2005
o don't assign remote/local host/port information manually between provided
struct in_conninfo and struct syncache, bcopy() it instead
o rename sc_tsrecent to sc_tsreflect in struct syncache to better capture
the purpose of this field
o rename sc_request_r_scale to sc_requested_r_scale for ditto reasons
o fix IPSEC error case printf's to report correct function name
o in syncache_socket() only transpose enhanced tcp options parameters to
struct tcpcb when the inpcb doesn't has TF_NOOPT set
o in syncache_respond() reorder stack variables
o in syncache_respond() remove bogus KASSERT()
No functional changes.
Sponsored by: TCP/IP Optimization Fundraise 2005
o redefine the parameter 'is_syn' to 'flags', add TO_SYN flag and adjust its
usage accordingly
o update the comments to the tcp_dooptions() invocation in
tcp_input():after_listen to reflect reality
o move the logic checking the echoed timestamp out of tcp_dooptions() to the
only place that uses it next to the invocation described in the previous
item
o adjust parsing of TCPOPT_SACK_PERMITTED to use the same style as the others
o add comments in to struct tcpopt.to_flags #defines
No functional changes.
Sponsored by: TCP/IP Optimization Fundraise 2005
ACK the SYN as required by RFC793, rather than ignoring it. NetBSD
have had a similar change since 1999.
PR: 93236
Submitted by: Grant Edwards <grante@visi.com>
MFC after: 1 month
as possible for the syncache_add() case. The syncache timer no longer
aquires the tcpinfo lock and timeout/retransmit runs can happen in
parallel with bucket granularity.
On a P4 the additional locks cause a slight degression of 0.7% in tcp
connections per second. When IP and TCP input are deserialized and
can run in parallel this little overhead can be neglected. The syncookie
handling still leaves room for improvement and its random salts may be
moved to the syncache bucket head structures to remove the second lock
operation currently required for it. However this would be a more
involved change from the way syncookies work at the moment.
Reviewed by: rwatson
Tested by: rwatson, ps (earlier version)
Sponsored by: TCP/IP Optimization Fundraise 2005
reference. For now, we allow the possibility that the in_ppcb
pointer in the inpcb may be NULL if a timewait socket has had its
tcptw structure recycled. This allows tcp_timewait() to
consistently unlock the inpcb.
Reported by: Kazuaki Oda <kaakun at highway dot ne dot jp>
MFC after: 3 months
tcp_timewait(). This corrects a bug (or lack of fixing of a bug)
in tcp_input.c:1.295.
Submitted by: Kazuaki Oda <kaakun at highway dot ne dot jp>
MFC after: 3 months
NULL. We currently do allow this to happen, but may want to remove that
possibility in the future. This case can occur when a socket is left
open after TCP wraps up, and the timewait state is recycled. This will
be cleaned up in the future.
Found by: Kazuaki Oda <kaakun at highway dot ne dot jp>
MFC after: 3 months
casts.
Consistently use intotw() to cast inp_ppcb pointers to struct tcptw *
pointers.
Consistently use intotcpcb() to cast inp_ppcb pointers to struct tcpcb *
pointers.
Don't assign tp to the results to intotcpcb() during variable declation
at the top of functions, as that is before the asserts relating to
locking have been performed. Do this later in the function after
appropriate assertions have run to allow that operation to be conisdered
safe.
MFC after: 3 months
pru_abort(), pru_detach(), and in_pcbdetach():
- Universally support and enforce the invariant that so_pcb is
never NULL, converting dozens of unnecessary NULL checks into
assertions, and eliminating dozens of unnecessary error handling
cases in protocol code.
- In some cases, eliminate unnecessary pcbinfo locking, as it is no
longer required to ensure so_pcb != NULL. For example, the receive
code no longer requires the pcbinfo lock, and the send code only
requires it if building a new connection on an otherwise unconnected
socket triggered via sendto() with an address. This should
significnatly reduce tcbinfo lock contention in the receive and send
cases.
- In order to support the invariant that so_pcb != NULL, it is now
necessary for the TCP code to not discard the tcpcb any time a
connection is dropped, but instead leave the tcpcb until the socket
is shutdown. This case is handled by setting INP_DROPPED, to
substitute for using a NULL so_pcb to indicate that the connection
has been dropped. This requires the inpcb lock, but not the pcbinfo
lock.
- Unlike all other protocols in the tree, TCP may need to retain access
to the socket after the file descriptor has been closed. Set
SS_PROTOREF in tcp_detach() in order to prevent the socket from being
freed, and add a flag, INP_SOCKREF, so that the TCP code knows whether
or not it needs to free the socket when the connection finally does
close. The typical case where this occurs is if close() is called on
a TCP socket before all sent data in the send socket buffer has been
transmitted or acknowledged. If INP_SOCKREF is found when the
connection is dropped, we release the inpcb, tcpcb, and socket instead
of flagging INP_DROPPED.
- Abort and detach protocol switch methods no longer return failures,
nor attempt to free sockets, as the socket layer does this.
- Annotate the existence of a long-standing race in the TCP timer code,
in which timers are stopped but not drained when the socket is freed,
as waiting for drain may lead to deadlocks, or have to occur in a
context where waiting is not permitted. This race has been handled
by testing to see if the tcpcb pointer in the inpcb is NULL (and vice
versa), which is not normally permitted, but may be true of a inpcb
and tcpcb have been freed. Add a counter to test how often this race
has actually occurred, and a large comment for each instance where
we compare potentially freed memory with NULL. This will have to be
fixed in the near future, but requires is to further address how to
handle the timer shutdown shutdown issue.
- Several TCP calls no longer potentially free the passed inpcb/tcpcb,
so no longer need to return a pointer to indicate whether the argument
passed in is still valid.
- Un-macroize debugging and locking setup for various protocol switch
methods for TCP, as it lead to more obscurity, and as locking becomes
more customized to the methods, offers less benefit.
- Assert copyright on tcp_usrreq.c due to significant modifications that
have been made as part of this work.
These changes significantly modify the memory management and connection
logic of our TCP implementation, and are (as such) High Risk Changes,
and likely to contain serious bugs. Please report problems to the
current@ mailing list ASAP, ideally with simple test cases, and
optionally, packet traces.
MFC after: 3 months
right from the beginning and partly clean up the differences in handling
between SYN_SENT and SYN_RCVD (syncache).
Further changes to this code to come. This is a first incremental step
to a general overhaul and streamlining of the TCP code.
PR: kern/15095
PR: kern/92690 (partly)
Reviewed by: qingli (and tested with ANVL)
Sponsored by: TCP/IP Optimization Fundraise 2005
simultaneous open. Both the bug and the patch were verified using the
ANVL test suite.
PR: kern/74935
Submitted by: qingli (before I became committer)
Reviewed by: andre
MFC after: 5 days
threshold. Inflight doesn't make sense on a LAN as it has
trouble figuring out the maximal bandwidth because of the coarse
tick granularity.
The sysctl net.inet.tcp.inflight.rttthresh specifies the threshold
in milliseconds below which inflight will disengage. It defaults
to 10ms.
Tested by: Joao Barros <joao.barros-at-gmail.com>,
Rich Murphey <rich-at-whiteoaklabs.com>
Sponsored by: TCP/IP Optimization Fundraise 2005
This fixes a bug in the previous commit.
Found by: Coverity Prevent(tm)
Coverity ID: CID253
Sponsored by: TCP/IP Optimization Fundraise 2005
MFC after: 3 days
include ip_options.h into all files making use of IP Options functions.
From ip_input.c rev 1.306:
ip_dooptions(struct mbuf *m, int pass)
save_rte(m, option, dst)
ip_srcroute(m0)
ip_stripoptions(m, mopt)
From ip_output.c rev 1.249:
ip_insertoptions(m, opt, phlen)
ip_optcopy(ip, jp)
ip_pcbopts(struct inpcb *inp, int optname, struct mbuf *m)
No functional changes in this commit.
Discussed with: rwatson
Sponsored by: TCP/IP Optimization Fundraise 2005
between sack and a bug in the "bad retransmit recovery" logic. This is
a workaround, the underlying bug will be fixed later.
Submitted by: Mohan Srinivasan, Noritoshi Demizu
TTL a packet must have when received on a socket. All packets with a
lower TTL are silently dropped. Works on already connected/connecting
and listening sockets for RAW/UDP/TCP.
This option is only really useful when set to 255 preventing packets
from outside the directly connected networks reaching local listeners
on sockets.
Allows userland implementation of 'The Generalized TTL Security Mechanism
(GTSM)' according to RFC3682. Examples of such use include the Cisco IOS
BGP implementation command "neighbor ttl-security".
MFC after: 2 weeks
Sponsored by: TCP/IP Optimization Fundraise 2005
after PAWS checks. The symptom of this is an inconsistency in the cached
sack state, caused by the fact that the sack scoreboard was not being
updated for an ACK handled in the header prediction path.
Found by: Andrey Chernov.
Submitted by: Noritoshi Demizu, Raja Mukerji.
Approved by: re
does not clear tlen and frees the mbuf (leaving th pointing at
freed memory), if the data segment is a complete duplicate.
This change works around that bug. A fix for the tcp_reass() bug
will appear later (that bug is benign for now, as neither th nor
tlen is referenced in tcp_input() after the call to tcp_reass()).
Found by: Pawel Jakub Dawidek.
Submitted by: Raja Mukerji, Noritoshi Demizu.
Approved by: re
The ipfw tables lookup code caches the result of the last query. The
kernel may process multiple packets concurrently, performing several
concurrent table lookups. Due to an insufficient locking, a cached
result can become corrupted that could cause some addresses to be
incorrectly matched against a lookup table.
Submitted by: ru
Reviewed by: csjp, mlaier
Security: CAN-2005-2019
Security: FreeBSD-SA-05:13.ipfw
Correct bzip2 permission race condition vulnerability.
Obtained from: Steve Grubb via RedHat
Security: CAN-2005-0953
Security: FreeBSD-SA-05:14.bzip2
Approved by: obrien
Correct TCP connection stall denial of service vulnerability.
A TCP packets with the SYN flag set is accepted for established
connections, allowing an attacker to overwrite certain TCP options.
Submitted by: Noritoshi Demizu
Reviewed by: andre, Mohan Srinivasan
Security: CAN-2005-2068
Security: FreeBSD-SA-05:15.tcp
Approved by: re (security blanket), cperciva
processing is now done in the ACK processing case.
- Merge tcp_sack_option() and tcp_del_sackholes() into a new function
called tcp_sack_doack().
- Test (SEG.ACK < SND.MAX) before processing the ACK.
Submitted by: Noritoshi Demizu
Reveiewed by: Mohan Srinivasan, Raja Mukerji
Approved by: re
or to compute the total retransmitted bytes in this sack recovery
episode, the scoreboard is traversed. While in sack recovery, this
traversal occurs on every call to tcp_output(), every dupack and
every partial ack. The scoreboard could potentially get quite large,
making this traversal expensive.
This change optimizes this by storing hints (for the next hole to
retransmit and the total retransmitted bytes in this sack recovery
episode) reducing the complexity to find these values from O(n) to
constant time.
The debug code that sanity checks the hints against the computed
value will be removed eventually.
Submitted by: Mohan Srinivasan, Noritoshi Demizu, Raja Mukerji.
in flight in SACK recovery.
Found by: Noritoshi Demizu
Submitted by: Mohan Srinivasan <mohans at yahoo-inc dot com>
Noritoshi Demizu <demizu at dd dot ij4u dot or dot jp>
Raja Mukerji <raja at moselle dot com>
setting ts_recent to an arbitrary value, stopping further
communication between the two hosts.
- If the Echoed Timestamp is greater than the current time,
fall back to the non RFC 1323 RTT calculation.
Submitted by: Raja Mukerji (raja at moselle dot com)
Reviewed by: Noritoshi Demizu, Mohan Srinivasan
a reassembly queue state structure, don't update (receiver) sack
report.
- Similarly, if tcp_drain() is called, freeing up all items on the
reassembly queue, clean the sack report.
Found, Submitted by: Noritoshi Demizu <demizu at dd dot iij4u dot or dot jp>
Reviewed by: Mohan Srinivasan (mohans at yahoo-inc dot com),
Raja Mukerji (raja at moselle dot com).
reported to the sender - in the case where the sender sends data
outside the window (as WinXP does :().
Reported by: Sam Jensen <sam at wand dot net dot nz>
Submitted by: Mohan Srinivasan
Remove the SACK "initburst" sysctl.
- Fix bugs in SACK dupack and partialack handling that can cause
large bursts while in SACK recovery.
Submitted by: Mohan Srinivasan
that the RFC 793 specification for accepting RST packets should be
following. When followed, this makes one vulnerable to the attacks
described in "slipping in the window", but it may be necessary in
some odd circumstances.
cases for tcp_input():
While it is true that the pcbinfo lock provides a pseudo-reference to
inpcbs, both the inpcb and pcbinfo locks are required to free an
un-referenced inpcb. As such, we can release the pcbinfo lock as
long as the inpcb remains locked with the confidence that it will not
be garbage-collected. This leads to a less conservative locking
strategy that should reduce contention on the TCP pcbinfo lock.
Discussed with: sam
pointer updates: test available space while holding the socket buffer
mutex, and continue to hold until until the pointer update has been
performed.
MFC after: 2 weeks
window was 0 bytes in size. This may have been the cause of unsolved
"connection not closing" reports over the years.
Thanks to Michiel Boland for providing the fix and providing a concise
test program for the problem.
Submitted by: Michiel Boland
MFC after: 2 weeks
contents of the tcpcb are read and modified in volume.
In tcp_input(), replace th comparison with 0 with a comparison with
NULL.
At the 'findpcb', 'dropafterack', and 'dropwithreset' labels in
tcp_input(), assert 'headlocked'. Try to improve consistency between
various assertions regarding headlocked to be more informative.
MFC after: 2 weeks
structure, so assert the inpcb lock associated with the tcptw.
Also assert the tcbinfo lock, as tcp_timewait() may call
tcp_twclose() or tcp_2msl_rest(), which require it. Since
tcp_timewait() is already called with that lock from tcp_input(),
this doesn't change current locking, merely documents reasons for
it.
In tcp_twstart(), assert the tcbinfo lock, as tcp_timer_2msl_rest()
is called, which requires that lock.
In tcp_twclose(), assert the tcbinfo lock, as tcp_timer_2msl_stop()
is called, which requires that lock.
Document the locking strategy for the time wait queues in tcp_timer.c,
which consists of protecting the time wait queues in the same manner
as the tcbinfo structure (using the tcbinfo lock).
In tcp_timer_2msl_reset(), assert the tcbinfo lock, as the time wait
queues are modified.
In tcp_timer_2msl_stop(), assert the tcbinfo lock, as the time wait
queues may be modified.
In tcp_timer_2msl_tw(), assert the tcbinfo lock, as the time wait
queues may be modified.
MFC after: 2 weeks
retain the pcbinfo lock until we're done using a pcb in the in-bound
path, as the pcbinfo lock acts as a pseuo-reference to prevent the pcb
from potentially being recycled. Clean up assertions and make sure to
assert that the pcbinfo is locked at the head of code subsections where
it is needed. Free the mbuf at the end of tcp_input after releasing
any held locks to reduce the time the locks are held.
MFC after: 3 weeks
A complete rationale and discussion is given in this message
and the resulting discussion:
http://docs.freebsd.org/cgi/mid.cgi?4177C8AD.6060706
Note that this commit removes only the functional part of T/TCP
from the tcp_* related functions in the kernel. Other features
introduced with RFC1644 are left intact (socket layer changes,
sendmsg(2) on connection oriented protocols) and are meant to
be reused by a simpler and less intrusive reimplemention of the
previous T/TCP functionality.
Discussed on: -arch
to control the packets injected while in sack recovery (for both
retransmissions and new data).
- Cleanups to the sack codepaths in tcp_output.c and tcp_sack.c.
- Add a new sysctl (net.inet.tcp.sack.initburst) that controls the
number of sack retransmissions done upon initiation of sack recovery.
Submitted by: Mohan Srinivasan <mohans@yahoo-inc.com>
and preserves the ipfw ABI. The ipfw core packet inspection and filtering
functions have not been changed, only how ipfw is invoked is different.
However there are many changes how ipfw is and its add-on's are handled:
In general ipfw is now called through the PFIL_HOOKS and most associated
magic, that was in ip_input() or ip_output() previously, is now done in
ipfw_check_[in|out]() in the ipfw PFIL handler.
IPDIVERT is entirely handled within the ipfw PFIL handlers. A packet to
be diverted is checked if it is fragmented, if yes, ip_reass() gets in for
reassembly. If not, or all fragments arrived and the packet is complete,
divert_packet is called directly. For 'tee' no reassembly attempt is made
and a copy of the packet is sent to the divert socket unmodified. The
original packet continues its way through ip_input/output().
ipfw 'forward' is done via m_tag's. The ipfw PFIL handlers tag the packet
with the new destination sockaddr_in. A check if the new destination is a
local IP address is made and the m_flags are set appropriately. ip_input()
and ip_output() have some more work to do here. For ip_input() the m_flags
are checked and a packet for us is directly sent to the 'ours' section for
further processing. Destination changes on the input path are only tagged
and the 'srcrt' flag to ip_forward() is set to disable destination checks
and ICMP replies at this stage. The tag is going to be handled on output.
ip_output() again checks for m_flags and the 'ours' tag. If found, the
packet will be dropped back to the IP netisr where it is going to be picked
up by ip_input() again and the directly sent to the 'ours' section. When
only the destination changes, the route's 'dst' is overwritten with the
new destination from the forward m_tag. Then it jumps back at the route
lookup again and skips the firewall check because it has been marked with
M_SKIP_FIREWALL. ipfw 'forward' has to be compiled into the kernel with
'option IPFIREWALL_FORWARD' to enable it.
DUMMYNET is entirely handled within the ipfw PFIL handlers. A packet for
a dummynet pipe or queue is directly sent to dummynet_io(). Dummynet will
then inject it back into ip_input/ip_output() after it has served its time.
Dummynet packets are tagged and will continue from the next rule when they
hit the ipfw PFIL handlers again after re-injection.
BRIDGING and IPFW_ETHER are not changed yet and use ipfw_chk() directly as
they did before. Later this will be changed to dedicated ETHER PFIL_HOOKS.
More detailed changes to the code:
conf/files
Add netinet/ip_fw_pfil.c.
conf/options
Add IPFIREWALL_FORWARD option.
modules/ipfw/Makefile
Add ip_fw_pfil.c.
net/bridge.c
Disable PFIL_HOOKS if ipfw for bridging is active. Bridging ipfw
is still directly invoked to handle layer2 headers and packets would
get a double ipfw when run through PFIL_HOOKS as well.
netinet/ip_divert.c
Removed divert_clone() function. It is no longer used.
netinet/ip_dummynet.[ch]
Neither the route 'ro' nor the destination 'dst' need to be stored
while in dummynet transit. Structure members and associated macros
are removed.
netinet/ip_fastfwd.c
Removed all direct ipfw handling code and replace it with the new
'ipfw forward' handling code.
netinet/ip_fw.h
Removed 'ro' and 'dst' from struct ip_fw_args.
netinet/ip_fw2.c
(Re)moved some global variables and the module handling.
netinet/ip_fw_pfil.c
New file containing the ipfw PFIL handlers and module initialization.
netinet/ip_input.c
Removed all direct ipfw handling code and replace it with the new
'ipfw forward' handling code. ip_forward() does not longer require
the 'next_hop' struct sockaddr_in argument. Disable early checks
if 'srcrt' is set.
netinet/ip_output.c
Removed all direct ipfw handling code and replace it with the new
'ipfw forward' handling code.
netinet/ip_var.h
Add ip_reass() as general function. (Used from ipfw PFIL handlers
for IPDIVERT.)
netinet/raw_ip.c
Directly check if ipfw and dummynet control pointers are active.
netinet/tcp_input.c
Rework the 'ipfw forward' to local code to work with the new way of
forward tags.
netinet/tcp_sack.c
Remove include 'opt_ipfw.h' which is not needed here.
sys/mbuf.h
Remove m_claim_next() macro which was exclusively for ipfw 'forward'
and is no longer needed.
Approved by: re (scottl)
- Trailing tab/space cleanup
- Remove spurious spaces between or before tabs
This change avoids touching files that Andre likely has in his working
set for PFIL hooks changes for IPFW/DUMMYNET.
Approved by: re (scottl)
Submitted by: Xin LI <delphij@frontfree.net>
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
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)
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.
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.
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.
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(?)
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
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
