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2005-11-17[TCP]: TCP highspeed build errorStephen Hemminger
There is a compile error that crept in with the last patch of TCP patches. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-16[IPV4,IPV6]: replace handmade list with hlist in IPv{4,6} reassemblyYasuyuki Kozakai
Both of ipq and frag_queue have *next and **prev, and they can be replaced with hlist. Thanks Arnaldo Carvalho de Melo for the suggestion. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-15[TCP]: More spelling fixes.Stephen Hemminger
From Joe Perches Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-14[NETFILTER] nfnetlink: unconditionally require CAP_NET_ADMINHarald Welte
This patch unconditionally requires CAP_NET_ADMIN for all nfnetlink messages. It also removes the per-message cap_required field, since all existing subsystems use CAP_NET_ADMIN for all their messages anyway. Patrick McHardy owes me a beer if we ever need to re-introduce this. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-14[NETFILTER] ctnetlink: More thorough size checking of attributesPablo Neira Ayuso
Add missing size checks. Thanks Patrick McHardy for the hint. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-14[NETFILTER] ctnetlink: use size_t to make gcc-4.x happyPablo Neira Ayuso
Make gcc-4.x happy. Use size_t instead of int. Thanks to Patrick McHardy for the hint. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-12[NETFILTER] {ip,nf}_conntrack TCP: Accept SYN+PUSH like SYNVlad Drukker
Some devices (e.g. Qlogic iSCSI HBA hardware like QLA4010 up to firmware 3.0.0.4) initiates TCP with SYN and PUSH flags set. The Linux TCP/IP stack deals fine with that, but the connection tracking code doesn't. This patch alters TCP connection tracking to accept SYN+PUSH as a valid flag combination. Signed-off-by: Vlad Drukker <vlad@storewiz.com> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-11[PATCH] TCP: fix vegas buildJeff Garzik
Recent TCP changes broke the build. Signed-off-by: Jeff Garzik <jgarzik@pobox.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-10[TCP]: speed up SACK processingStephen Hemminger
Use "hints" to speed up the SACK processing. Various forms of this have been used by TCP developers (Web100, STCP, BIC) to avoid the 2x linear search of outstanding segments. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10[TCP]: spelling fixesStephen Hemminger
Minor spelling fixes for TCP code. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10[TCP]: receive buffer growth limiting with mixed MTUJohn Heffner
This is a patch for discussion addressing some receive buffer growing issues. This is partially related to the thread "Possible BUG in IPv4 TCP window handling..." last week. Specifically it addresses the problem of an interaction between rcvbuf moderation (receiver autotuning) and rcv_ssthresh. The problem occurs when sending small packets to a receiver with a larger MTU. (A very common case I have is a host with a 1500 byte MTU sending to a host with a 9k MTU.) In such a case, the rcv_ssthresh code is targeting a window size corresponding to filling up the current rcvbuf, not taking into account that the new rcvbuf moderation may increase the rcvbuf size. One hunk makes rcv_ssthresh use tcp_rmem[2] as the size target rather than rcvbuf. The other changes the behavior when it overflows its memory bounds with in-order data so that it tries to grow rcvbuf (the same as with out-of-order data). These changes should help my problem of mixed MTUs, and should also help the case from last week's thread I think. (In both cases though you still need tcp_rmem[2] to be set much larger than the TCP window.) One question is if this is too aggressive at trying to increase rcvbuf if it's under memory stress. Orignally-from: John Heffner <jheffner@psc.edu> Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10[TCP]: Appropriate Byte Count supportStephen Hemminger
This is an updated version of the RFC3465 ABC patch originally for Linux 2.6.11-rc4 by Yee-Ting Li. ABC is a way of counting bytes ack'd rather than packets when updating congestion control. The orignal ABC described in the RFC applied to a Reno style algorithm. For advanced congestion control there is little change after leaving slow start. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10[TCP]: add tcp_slow_start helperStephen Hemminger
Move all the code that does linear TCP slowstart to one inline function to ease later patch to add ABC support. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10[TCP]: simplify microsecond rtt samplingStephen Hemminger
Simplify the code that comuputes microsecond rtt estimate used by TCP Vegas. Move the callback out of the RTT sampler and into the end of the ack cleanup. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10[TCP]: fix congestion window update when using TSO deferalStephen Hemminger
TCP peformance with TSO over networks with delay is awful. On a 100Mbit link with 150ms delay, we get 4Mbits/sec with TSO and 50Mbits/sec without TSO. The problem is with TSO, we intentionally do not keep the maximum number of packets in flight to fill the window, we hold out to until we can send a MSS chunk. But, we also don't update the congestion window unless we have filled, as per RFC2861. This patch replaces the check for the congestion window being full with something smarter that accounts for TSO. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10[NET]: Detect hardware rx checksum faults correctlyHerbert Xu
Here is the patch that introduces the generic skb_checksum_complete which also checks for hardware RX checksum faults. If that happens, it'll call netdev_rx_csum_fault which currently prints out a stack trace with the device name. In future it can turn off RX checksum. I've converted every spot under net/ that does RX checksum checks to use skb_checksum_complete or __skb_checksum_complete with the exceptions of: * Those places where checksums are done bit by bit. These will call netdev_rx_csum_fault directly. * The following have not been completely checked/converted: ipmr ip_vs netfilter dccp This patch is based on patches and suggestions from Stephen Hemminger and David S. Miller. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10[NETLINK]: Make netlink_callback->done() optionalThomas Graf
Most netlink families make no use of the done() callback, making it optional gets rid of all unnecessary dummy implementations. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER]: Add nf_conntrack subsystem.Yasuyuki Kozakai
The existing connection tracking subsystem in netfilter can only handle ipv4. There were basically two choices present to add connection tracking support for ipv6. We could either duplicate all of the ipv4 connection tracking code into an ipv6 counterpart, or (the choice taken by these patches) we could design a generic layer that could handle both ipv4 and ipv6 and thus requiring only one sub-protocol (TCP, UDP, etc.) connection tracking helper module to be written. In fact nf_conntrack is capable of working with any layer 3 protocol. The existing ipv4 specific conntrack code could also not deal with the pecularities of doing connection tracking on ipv6, which is also cured here. For example, these issues include: 1) ICMPv6 handling, which is used for neighbour discovery in ipv6 thus some messages such as these should not participate in connection tracking since effectively they are like ARP messages 2) fragmentation must be handled differently in ipv6, because the simplistic "defrag, connection track and NAT, refrag" (which the existing ipv4 connection tracking does) approach simply isn't feasible in ipv6 3) ipv6 extension header parsing must occur at the correct spots before and after connection tracking decisions, and there were no provisions for this in the existing connection tracking design 4) ipv6 has no need for stateful NAT The ipv4 specific conntrack layer is kept around, until all of the ipv4 specific conntrack helpers are ported over to nf_conntrack and it is feature complete. Once that occurs, the old conntrack stuff will get placed into the feature-removal-schedule and we will fully kill it off 6 months later. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-09[NETFILTER] ctnetlink: ICMP_ID is u_int16_t not u_int8_t.Krzysztof Piotr Oledzki
Signed-off-by: Krzysztof Piotr Oledzki <ole@ans.pl> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] ctnetlink: Fix oops when no ICMP ID info in messageKrzysztof Piotr Oledzki
This patch fixes an userspace triggered oops. If there is no ICMP_ID info the reference to attr will be NULL. Signed-off-by: Krzysztof Piotr Oledzki <ole@ans.pl> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] ctnetlink: Add support to identify expectations by ID'sPablo Neira Ayuso
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] ctnetlink: propagate error instaed of returning -EPERMPablo Neira Ayuso
Propagate the error to userspace instead of returning -EPERM if the get conntrack operation fails. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] ctnetlink: return -EINVAL if size is wrongPablo Neira Ayuso
Return -EINVAL if the size isn't OK instead of -EPERM. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER]: stop tracking ICMP error at early pointYasuyuki Kozakai
Currently connection tracking handles ICMP error like normal packets if it failed to get related connection. But it fails that after all. This makes connection tracking stop tracking ICMP error at early point. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] PPTP helper: fix PNS-PAC expectation call idPhilip Craig
The reply tuple of the PNS->PAC expectation was using the wrong call id. So we had the following situation: - PNS behind NAT firewall - PNS call id requires NATing - PNS->PAC gre packet arrives first then the PNS->PAC expectation is matched, and the other expectation is deleted, but the PAC->PNS gre packets do not match the gre conntrack because the call id is wrong. We also cannot use ip_nat_follow_master(). Signed-off-by: Philip Craig <philipc@snapgear.com> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] ctnetlink: get_conntrack can use GFP_KERNELPablo Neira Ayuso
ctnetlink_get_conntrack is always called from user context, so GFP_KERNEL is enough. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] ctnetlink: kill unused includesPablo Neira Ayuso
Kill some useless headers included in ctnetlink. They aren't used in any way. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] ctnetlink: add module alias to fix autoloadingPablo Neira Ayuso
Add missing module alias. This is a must to load ctnetlink on demand. For example, the conntrack tool will fail if the module isn't loaded. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] ctnetlink: add marking support from userspacePablo Neira Ayuso
This patch adds support for conntrack marking from user space. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] ctnetlink: check if protoinfo is presentPablo Neira Ayuso
This fixes an oops triggered from userspace. If we don't pass information about the private protocol info, the reference to attr will be NULL. This is likely to happen in update messages. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER] nfnetlink: nfattr_parse() can never fail, make it voidHarald Welte
nfattr_parse (and thus nfattr_parse_nested) always returns success. So we can make them 'void' and remove all the checking at the caller side. Based on original patch by Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER]: refcount leak of proto when ctnetlink dumping tupleYasuyuki Kozakai
Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-09[NETFILTER]: packet counter of conntrack is 32bitsYasuyuki Kozakai
The packet counter variable of conntrack was changed to 32bits from 64bits. This follows that change. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-08[IPV4]: Fix ip_queue_xmit identity increment for TSO packetsHerbert Xu
When ip_queue_xmit calls ip_select_ident_more for IP identity selection it gives it the wrong packet count for TSO packets. The ip_select_* functions expect one less than the number of packets, so we need to subtract one for TSO packets. This bug was diagnosed and fixed by Tom Young. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-08[NET]: kfree cleanupJesper Juhl
From: Jesper Juhl <jesper.juhl@gmail.com> This is the net/ part of the big kfree cleanup patch. Remove pointless checks for NULL prior to calling kfree() in net/. Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Arnaldo Carvalho de Melo <acme@conectiva.com.br> Acked-by: Marcel Holtmann <marcel@holtmann.org> Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: Andrew Morton <akpm@osdl.org>
2005-11-08[IPVS]: fix connection leak if expire_nodest_conn=1Julian Anastasov
There was a fix in 2.6.13 that changed the behaviour of ip_vs_conn_expire_now function not to put reference to connection, its callers should hold write lock or connection refcnt. But we forgot to convert one caller, when the real server for connection is unavailable caller should put the connection reference. It happens only when sysctl var expire_nodest_conn is set to 1 and such connections never expire. Thanks to Roberto Nibali who found the problem and tested a 2.4.32-rc2 patch, which is equal to this 2.6 version. Patch for 2.4 is already sent to Marcelo. Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Roberto Nibali <ratz@drugphish.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-05[TCP/DCCP]: Randomize port selectionStephen Hemminger
This patch randomizes the port selected on bind() for connections to help with possible security attacks. It should also be faster in most cases because there is no need for a global lock. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-05[NETFILTER]: CONNMARK target needs ip_conntrackHarald Welte
There's a missing dependency from the CONNMARK target to ip_conntrack. Signed-off-by: Pablo Neira Ayuso <pablo@eurodev.net> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-05[NETFILTER]: Fix double free after netlink_unicast() in ctnetlinkHarald Welte
It's not necessary to free skb if netlink_unicast() failed. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-05[NETFILTER] NAT: Fix module refcount dropping too farHarald Welte
The unknown protocol is used as a fallback when a protocol isn't known. Hence we cannot handle it failing, so don't set ".me". It's OK, since we only grab a reference from within the same module (iptable_nat.ko), so we never take the module refcount from 0 to 1. Also, remove the "protocol is NULL" test: it's never NULL. Signed-off-by: Rusty Rusty <rusty@rustcorp.com.au> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-04[NETFILTER] PPTP helper: Fix endianness bug in GRE key / CallID NATHarald Welte
This endianness bug slipped through while changing the 'gre.key' field in the conntrack tuple from 32bit to 16bit. None of my tests caught the problem, since the linux pptp client always has '0' as call id / gre key. Only windows clients actually trigger the bug. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-04[NETFILTER] PPTP helper: Fix compilation of conntrack helper without NATHarald Welte
This patch fixes compilation of the PPTP conntrack helper when NAT is configured off. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-02[TCP]: BIC max increment too largeStephen Hemminger
The max growth of BIC TCP is too large. Original code was based on BIC 1.0 and the default there was 32. Later code (2.6.13) included compensation for delayed acks, and should have reduced the default value to 16; since normally TCP gets one ack for every two packets sent. The current value of 32 makes BIC too aggressive and unfair to other flows. Submitted-by: Injong Rhee <rhee@eos.ncsu.edu> Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Acked-by: Ian McDonald <imcdnzl@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-11-02[MCAST]: ip[6]_mc_add_src should be called when number of sources is zeroYan Zheng
And filter mode is exclude. Further explanation by David Stevens: Multicast source filters aren't widely used yet, and that's really the only feature that's affected if an application actually exercises this bug, as far as I can tell. An ordinary filter-less multicast join should still work, and only forwarded multicast traffic making use of filters and doing empty-source filters with the MSFILTER ioctl would be at risk of not getting multicast traffic forwarded to them because the reports generated would not be based on the correct counts. Signed-off-by: Yan Zheng <yanzheng@21cn.com Acked-by: David L Stevens <dlstevens@us.ibm.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-10-31[NETFILTER]: Add "revision" support to arp_tables and ip6_tablesHarald Welte
Like ip_tables already has it for some time, this adds support for having multiple revisions for each match/target. We steal one byte from the name in order to accomodate a 8 bit version number. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-10-30[PATCH] Typo fix: dot after newline in printk stringsJean Delvare
Typo fix: dots appearing after a newline in printk strings. Signed-off-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29[IPV4]: Fix issue reported by Coverity in ipv4/fib_frontend.cJayachandran C
fib_del_ifaddr() dereferences ifa->ifa_dev, so the code already assumes that ifa->ifa_dev is non-NULL, the check is unnecessary. Signed-off-by: Jayachandran C. <c.jayachandran at gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-10-28[IPv4/IPv6]: UFO Scatter-gather approachAnanda Raju
Attached is kernel patch for UDP Fragmentation Offload (UFO) feature. 1. This patch incorporate the review comments by Jeff Garzik. 2. Renamed USO as UFO (UDP Fragmentation Offload) 3. udp sendfile support with UFO This patches uses scatter-gather feature of skb to generate large UDP datagram. Below is a "how-to" on changes required in network device driver to use the UFO interface. UDP Fragmentation Offload (UFO) Interface: ------------------------------------------- UFO is a feature wherein the Linux kernel network stack will offload the IP fragmentation functionality of large UDP datagram to hardware. This will reduce the overhead of stack in fragmenting the large UDP datagram to MTU sized packets 1) Drivers indicate their capability of UFO using dev->features |= NETIF_F_UFO | NETIF_F_HW_CSUM | NETIF_F_SG NETIF_F_HW_CSUM is required for UFO over ipv6. 2) UFO packet will be submitted for transmission using driver xmit routine. UFO packet will have a non-zero value for "skb_shinfo(skb)->ufo_size" skb_shinfo(skb)->ufo_size will indicate the length of data part in each IP fragment going out of the adapter after IP fragmentation by hardware. skb->data will contain MAC/IP/UDP header and skb_shinfo(skb)->frags[] contains the data payload. The skb->ip_summed will be set to CHECKSUM_HW indicating that hardware has to do checksum calculation. Hardware should compute the UDP checksum of complete datagram and also ip header checksum of each fragmented IP packet. For IPV6 the UFO provides the fragment identification-id in skb_shinfo(skb)->ip6_frag_id. The adapter should use this ID for generating IPv6 fragments. Signed-off-by: Ananda Raju <ananda.raju@neterion.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (forwarded) Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2005-10-28Merge master.kernel.org:/pub/scm/linux/kernel/git/acme/net-2.6.15Linus Torvalds
2005-10-27[TCP]: Clear stale pred_flags when snd_wnd changesHerbert Xu
This bug is responsible for causing the infamous "Treason uncloaked" messages that's been popping up everywhere since the printk was added. It has usually been blamed on foreign operating systems. However, some of those reports implicate Linux as both systems are running Linux or the TCP connection is going across the loopback interface. In fact, there really is a bug in the Linux TCP header prediction code that's been there since at least 2.1.8. This bug was tracked down with help from Dale Blount. The effect of this bug ranges from harmless "Treason uncloaked" messages to hung/aborted TCP connections. The details of the bug and fix is as follows. When snd_wnd is updated, we only update pred_flags if tcp_fast_path_check succeeds. When it fails (for example, when our rcvbuf is used up), we will leave pred_flags with an out-of-date snd_wnd value. When the out-of-date pred_flags happens to match the next incoming packet we will again hit the fast path and use the current snd_wnd which will be wrong. In the case of the treason messages, it just happens that the snd_wnd cached in pred_flags is zero while tp->snd_wnd is non-zero. Therefore when a zero-window packet comes in we incorrectly conclude that the window is non-zero. In fact if the peer continues to send us zero-window pure ACKs we will continue making the same mistake. It's only when the peer transmits a zero-window packet with data attached that we get a chance to snap out of it. This is what triggers the treason message at the next retransmit timeout. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>