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2012-08-31tcp: TCP Fast Open Server - header & support functionsJerry Chu
This patch adds all the necessary data structure and support functions to implement TFO server side. It also documents a number of flags for the sysctl_tcp_fastopen knob, and adds a few Linux extension MIBs. In addition, it includes the following: 1. a new TCP_FASTOPEN socket option an application must call to supply a max backlog allowed in order to enable TFO on its listener. 2. A number of key data structures: "fastopen_rsk" in tcp_sock - for a big socket to access its request_sock for retransmission and ack processing purpose. It is non-NULL iff 3WHS not completed. "fastopenq" in request_sock_queue - points to a per Fast Open listener data structure "fastopen_queue" to keep track of qlen (# of outstanding Fast Open requests) and max_qlen, among other things. "listener" in tcp_request_sock - to point to the original listener for book-keeping purpose, i.e., to maintain qlen against max_qlen as part of defense against IP spoofing attack. 3. various data structure and functions, many in tcp_fastopen.c, to support server side Fast Open cookie operations, including /proc/sys/net/ipv4/tcp_fastopen_key to allow manual rekeying. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-31tcp: Increase timeout for SYN segmentsAlex Bergmann
Commit 9ad7c049 ("tcp: RFC2988bis + taking RTT sample from 3WHS for the passive open side") changed the initRTO from 3secs to 1sec in accordance to RFC6298 (former RFC2988bis). This reduced the time till the last SYN retransmission packet gets sent from 93secs to 31secs. RFC1122 is stating that the retransmission should be done for at least 3 minutes, but this seems to be quite high. "However, the values of R1 and R2 may be different for SYN and data segments. In particular, R2 for a SYN segment MUST be set large enough to provide retransmission of the segment for at least 3 minutes. The application can close the connection (i.e., give up on the open attempt) sooner, of course." This patch increases the value of TCP_SYN_RETRIES to the value of 6, providing a retransmission window of 63secs. The comments for SYN and SYNACK retries have also been updated to describe the current settings. The same goes for the documentation file "Documentation/networking/ip-sysctl.txt". Signed-off-by: Alexander Bergmann <alex@linlab.net> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-30ipv4: remove rt_cache_rebuild_countEric Dumazet
After IP route cache removal, rt_cache_rebuild_count is no longer used. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-22sctp: Implement quick failover draft from tsvwgNeil Horman
I've seen several attempts recently made to do quick failover of sctp transports by reducing various retransmit timers and counters. While its possible to implement a faster failover on multihomed sctp associations, its not particularly robust, in that it can lead to unneeded retransmits, as well as false connection failures due to intermittent latency on a network. Instead, lets implement the new ietf quick failover draft found here: http://tools.ietf.org/html/draft-nishida-tsvwg-sctp-failover-05 This will let the sctp stack identify transports that have had a small number of errors, and avoid using them quickly until their reliability can be re-established. I've tested this out on two virt guests connected via multiple isolated virt networks and believe its in compliance with the above draft and works well. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Vlad Yasevich <vyasevich@gmail.com> CC: Sridhar Samudrala <sri@us.ibm.com> CC: "David S. Miller" <davem@davemloft.net> CC: linux-sctp@vger.kernel.org CC: joe@perches.com Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-19net-tcp: Fast Open client - cookie-less modeYuchung Cheng
In trusted networks, e.g., intranet, data-center, the client does not need to use Fast Open cookie to mitigate DoS attacks. In cookie-less mode, sendmsg() with MSG_FASTOPEN flag will send SYN-data regardless of cookie availability. Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-19net-tcp: Fast Open client - sendmsg(MSG_FASTOPEN)Yuchung Cheng
sendmsg() (or sendto()) with MSG_FASTOPEN is a combo of connect(2) and write(2). The application should replace connect() with it to send data in the opening SYN packet. For blocking socket, sendmsg() blocks until all the data are buffered locally and the handshake is completed like connect() call. It returns similar errno like connect() if the TCP handshake fails. For non-blocking socket, it returns the number of bytes queued (and transmitted in the SYN-data packet) if cookie is available. If cookie is not available, it transmits a data-less SYN packet with Fast Open cookie request option and returns -EINPROGRESS like connect(). Using MSG_FASTOPEN on connecting or connected socket will result in simlar errno like repeating connect() calls. Therefore the application should only use this flag on new sockets. The buffer size of sendmsg() is independent of the MSS of the connection. Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-17tcp: implement RFC 5961 3.2Eric Dumazet
Implement the RFC 5691 mitigation against Blind Reset attack using RST bit. Idea is to validate incoming RST sequence, to match RCV.NXT value, instead of previouly accepted window : (RCV.NXT <= SEG.SEQ < RCV.NXT+RCV.WND) If sequence is in window but not an exact match, send a "challenge ACK", so that the other part can resend an RST with the appropriate sequence. Add a new sysctl, tcp_challenge_ack_limit, to limit number of challenge ACK sent per second. Add a new SNMP counter to count number of challenge acks sent. (netstat -s | grep TCPChallengeACK) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Kiran Kumar Kella <kkiran@broadcom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-11tcp: TCP Small QueuesEric Dumazet
This introduce TSQ (TCP Small Queues) TSQ goal is to reduce number of TCP packets in xmit queues (qdisc & device queues), to reduce RTT and cwnd bias, part of the bufferbloat problem. sk->sk_wmem_alloc not allowed to grow above a given limit, allowing no more than ~128KB [1] per tcp socket in qdisc/dev layers at a given time. TSO packets are sized/capped to half the limit, so that we have two TSO packets in flight, allowing better bandwidth use. As a side effect, setting the limit to 40000 automatically reduces the standard gso max limit (65536) to 40000/2 : It can help to reduce latencies of high prio packets, having smaller TSO packets. This means we divert sock_wfree() to a tcp_wfree() handler, to queue/send following frames when skb_orphan() [2] is called for the already queued skbs. Results on my dev machines (tg3/ixgbe nics) are really impressive, using standard pfifo_fast, and with or without TSO/GSO. Without reduction of nominal bandwidth, we have reduction of buffering per bulk sender : < 1ms on Gbit (instead of 50ms with TSO) < 8ms on 100Mbit (instead of 132 ms) I no longer have 4 MBytes backlogged in qdisc by a single netperf session, and both side socket autotuning no longer use 4 Mbytes. As skb destructor cannot restart xmit itself ( as qdisc lock might be taken at this point ), we delegate the work to a tasklet. We use one tasklest per cpu for performance reasons. If tasklet finds a socket owned by the user, it sets TSQ_OWNED flag. This flag is tested in a new protocol method called from release_sock(), to eventually send new segments. [1] New /proc/sys/net/ipv4/tcp_limit_output_bytes tunable [2] skb_orphan() is usually called at TX completion time, but some drivers call it in their start_xmit() handler. These drivers should at least use BQL, or else a single TCP session can still fill the whole NIC TX ring, since TSQ will have no effect. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Dave Taht <dave.taht@bufferbloat.net> Cc: Tom Herbert <therbert@google.com> Cc: Matt Mathis <mattmathis@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-30ipv4: Clarify in docs that accept_local requires rp_filter.David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-12ipv4: Add interface option to enable routing of 127.0.0.0/8Thomas Graf
Routing of 127/8 is tradtionally forbidden, we consider packets from that address block martian when routing and do not process corresponding ARP requests. This is a sane default but renders a huge address space practically unuseable. The RFC states that no address within the 127/8 block should ever appear on any network anywhere but it does not forbid the use of such addresses outside of the loopback device in particular. For example to address a pool of virtual guests behind a load balancer. This patch adds a new interface option 'route_localnet' enabling routing of the 127/8 address block and processing of ARP requests on a specific interface. Note that for the feature to work, the default local route covering 127/8 dev lo needs to be removed. Example: $ sysctl -w net.ipv4.conf.eth0.route_localnet=1 $ ip route del 127.0.0.0/8 dev lo table local $ ip addr add 127.1.0.1/16 dev eth0 $ ip route flush cache V2: Fix invalid check to auto flush cache (thanks davem) Signed-off-by: Thomas Graf <tgraf@suug.ch> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-08netfilter: bridge: optionally set indev to vlanPablo Neira Ayuso
if net.bridge.bridge-nf-filter-vlan-tagged sysctl is enabled, bridge netfilter removes the vlan header temporarily and then feeds the packet to ip(6)tables. When the new "bridge-nf-pass-vlan-input-device" sysctl is on (default off), then bridge netfilter will also set the in-interface to the vlan interface; if such an interface exists. This is needed to make iptables REDIRECT target work with "vlan-on-top-of-bridge" setups and to allow use of "iptables -i" to match the vlan device name. Also update Documentation with current brnf default settings. Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Bart De Schuymer <bdschuym@pandora.be> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2012-05-07Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/ethernet/intel/e1000e/param.c drivers/net/wireless/iwlwifi/iwl-agn-rx.c drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c drivers/net/wireless/iwlwifi/iwl-trans.h Resolved the iwlwifi conflict with mainline using 3-way diff posted by John Linville and Stephen Rothwell. In 'net' we added a bug fix to make iwlwifi report a more accurate skb->truesize but this conflicted with RX path changes that happened meanwhile in net-next. In e1000e a conflict arose in the validation code for settings of adapter->itr. 'net-next' had more sophisticated logic so that logic was used. Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-02tcp: change tcp_adv_win_scale and tcp_rmem[2]Eric Dumazet
tcp_adv_win_scale default value is 2, meaning we expect a good citizen skb to have skb->len / skb->truesize ratio of 75% (3/4) In 2.6 kernels we (mis)accounted for typical MSS=1460 frame : 1536 + 64 + 256 = 1856 'estimated truesize', and 1856 * 3/4 = 1392. So these skbs were considered as not bloated. With recent truesize fixes, a typical MSS=1460 frame truesize is now the more precise : 2048 + 256 = 2304. But 2304 * 3/4 = 1728. So these skb are not good citizen anymore, because 1460 < 1728 (GRO can escape this problem because it build skbs with a too low truesize.) This also means tcp advertises a too optimistic window for a given allocated rcvspace : When receiving frames, sk_rmem_alloc can hit sk_rcvbuf limit and we call tcp_prune_queue()/tcp_collapse() too often, especially when application is slow to drain its receive queue or in case of losses (netperf is fast, scp is slow). This is a major latency source. We should adjust the len/truesize ratio to 50% instead of 75% This patch : 1) changes tcp_adv_win_scale default to 1 instead of 2 2) increase tcp_rmem[2] limit from 4MB to 6MB to take into account better truesize tracking and to allow autotuning tcp receive window to reach same value than before. Note that same amount of kernel memory is consumed compared to 2.6 kernels. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-02tcp: early retransmitYuchung Cheng
This patch implements RFC 5827 early retransmit (ER) for TCP. It reduces DUPACK threshold (dupthresh) if outstanding packets are less than 4 to recover losses by fast recovery instead of timeout. While the algorithm is simple, small but frequent network reordering makes this feature dangerous: the connection repeatedly enter false recovery and degrade performance. Therefore we implement a mitigation suggested in the appendix of the RFC that delays entering fast recovery by a small interval, i.e., RTT/4. Currently ER is conservative and is disabled for the rest of the connection after the first reordering event. A large scale web server experiment on the performance impact of ER is summarized in section 6 of the paper "Proportional Rate Reduction for TCP”, IMC 2011. http://conferences.sigcomm.org/imc/2011/docs/p155.pdf Note that Linux has a similar feature called THIN_DUPACK. The differences are THIN_DUPACK do not mitigate reorderings and is only used after slow start. Currently ER is disabled if THIN_DUPACK is enabled. I would be happy to merge THIN_DUPACK feature with ER if people think it's a good idea. ER is enabled by sysctl_tcp_early_retrans: 0: Disables ER 1: Reduce dupthresh to packets_out - 1 when outstanding packets < 4. 2: (Default) reduce dupthresh like mode 1. In addition, delay entering fast recovery by RTT/4. Note: mode 2 is implemented in the third part of this patch series. Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-27net: doc: merge /proc/sys/net/core/* documents into one placeShan Wei
All parameter descriptions in /proc/sys/net/core/* now is separated two places. So, merge them into Documentation/sysctl/net.txt. Signed-off-by: Shan Wei <davidshan@tencent.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-03TCP: update ip_local_port_range documentationFernando Luis Vazquez Cao
The explanation of ip_local_port_range in Documentation/networking/ip-sysctl.txt contains several factual errors: - The default value of ip_local_port_range does not depend on the amount of memory available in the system. - tcp_tw_recycle is not enabled by default. - 1024-4999 is not the default value. - Etc. Clean up the mess. Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
2011-12-06ipv4:correct description for tcp_max_syn_backlogPeter Pan(潘卫平)
Since commit c5ed63d66f24(tcp: fix three tcp sysctls tuning), sysctl_max_syn_backlog is determined by tcp_hashinfo->ehash_mask, and the minimal value is 128, and it will increase in proportion to the memory of machine. The original description for tcp_max_syn_backlog and sysctl_max_syn_backlog are out of date. Changelog: V2: update description for sysctl_max_syn_backlog Signed-off-by: Weiping Pan <panweiping3@gmail.com> Reviewed-by: Shan Wei <shanwei88@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-30tcp: inherit listener congestion control for passive cnxEric Dumazet
Rick Jones reported that TCP_CONGESTION sockopt performed on a listener was ignored for its children sockets : right after accept() the congestion control for new socket is the system default one. This seems an oversight of the initial design (quoted from Stephen) Based on prior investigation and patch from Rick. Reported-by: Rick Jones <rick.jones2@hp.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Stephen Hemminger <shemminger@vyatta.com> CC: Yuchung Cheng <ycheng@google.com> Tested-by: Rick Jones <rick.jones2@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-14neigh: new unresolved queue limitsEric Dumazet
Le mercredi 09 novembre 2011 à 16:21 -0500, David Miller a écrit : > From: David Miller <davem@davemloft.net> > Date: Wed, 09 Nov 2011 16:16:44 -0500 (EST) > > > From: Eric Dumazet <eric.dumazet@gmail.com> > > Date: Wed, 09 Nov 2011 12:14:09 +0100 > > > >> unres_qlen is the number of frames we are able to queue per unresolved > >> neighbour. Its default value (3) was never changed and is responsible > >> for strange drops, especially if IP fragments are used, or multiple > >> sessions start in parallel. Even a single tcp flow can hit this limit. > > ... > > > > Ok, I've applied this, let's see what happens :-) > > Early answer, build fails. > > Please test build this patch with DECNET enabled and resubmit. The > decnet neigh layer still refers to the removed ->queue_len member. > > Thanks. Ouch, this was fixed on one machine yesterday, but not the other one I used this morning, sorry. [PATCH V5 net-next] neigh: new unresolved queue limits unres_qlen is the number of frames we are able to queue per unresolved neighbour. Its default value (3) was never changed and is responsible for strange drops, especially if IP fragments are used, or multiple sessions start in parallel. Even a single tcp flow can hit this limit. $ arp -d 192.168.20.108 ; ping -c 2 -s 8000 192.168.20.108 PING 192.168.20.108 (192.168.20.108) 8000(8028) bytes of data. 8008 bytes from 192.168.20.108: icmp_seq=2 ttl=64 time=0.322 ms Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-08net: min_pmtu default is 552Eric Dumazet
Small fix in Documentation, since min_pmtu is 512 + 20 + 20 = 552 Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-10-07Merge branch 'master' of github.com:davem330/netDavid S. Miller
Conflicts: net/batman-adv/soft-interface.c
2011-09-29net: Documentation: Fix type of variablesRoy.Li
Signed-off-by: Roy.Li <rongqing.li@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-09-22Merge branch 'master' of github.com:davem330/netDavid S. Miller
Conflicts: MAINTAINERS drivers/net/Kconfig drivers/net/ethernet/broadcom/bnx2x/bnx2x_link.c drivers/net/ethernet/broadcom/tg3.c drivers/net/wireless/iwlwifi/iwl-pci.c drivers/net/wireless/iwlwifi/iwl-trans-tx-pcie.c drivers/net/wireless/rt2x00/rt2800usb.c drivers/net/wireless/wl12xx/main.c
2011-09-16ipv6: Send ICMPv6 RSes only when RAs are acceptedTore Anderson
This patch improves the logic determining when to send ICMPv6 Router Solicitations, so that they are 1) always sent when the kernel is accepting Router Advertisements, and 2) never sent when the kernel is not accepting RAs. In other words, the operational setting of the "accept_ra" sysctl is used. The change also makes the special "Hybrid Router" forwarding mode ("forwarding" sysctl set to 2) operate exactly the same as the standard Router mode (forwarding=1). The only difference between the two was that RSes was being sent in the Hybrid Router mode only. The sysctl documentation describing the special Hybrid Router mode has therefore been removed. Rationale for the change: Currently, the value of forwarding sysctl is the only thing determining whether or not to send RSes. If it has the value 0 or 2, they are sent, otherwise they are not. This leads to inconsistent behaviour in the following cases: * accept_ra=0, forwarding=0 * accept_ra=0, forwarding=2 * accept_ra=1, forwarding=2 * accept_ra=2, forwarding=1 In the first three cases, the kernel will send RSes, even though it will not accept any RAs received in reply. In the last case, it will not send any RSes, even though it will accept and process any RAs received. (Most routers will send unsolicited RAs periodically, so suppressing RSes in the last case will merely delay auto-configuration, not prevent it.) Also, it is my opinion that having the forwarding sysctl control RS sending behaviour (completely independent of whether RAs are being accepted or not) is simply not what most users would intuitively expect to be the case. Signed-off-by: Tore Anderson <tore@fud.no> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-08-22net: Documentation: RFC 2553bis is now RFC 3493Geoffrey Thomas
Signed-off-by: Geoffrey Thomas <geofft@mit.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-07-14Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: net/bluetooth/l2cap_core.c
2011-07-08net: Fix default in docs for tcp_orphan_retries.David S. Miller
Default should be listed at 8 instead of 7. Reported-by: Denys Fedoryshchenko <denys@visp.net.lb> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-07-04Update documented default values for various TCP/UDP tunablesMax Matveev
tcp_rmem and tcp_wmem use 1 page as default value for the minimum amount of memory to be used, same as udp_wmem_min and udp_rmem_min. Pages are different size on different architectures - use the right units when describing the defaults. Reviewed-by: Shan Wei <shanwei@cn.fujitsu.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Max Matveev <makc@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-07-04Update description of net.sctp.sctp_rmem and net.sctp.sctp_wmem tunablesMax Matveev
sctp does not use second and third ("default" and "max") values of sctp_rmem tunable. The format is the same as tcp_rmem but the meaning is different so make the documentation explicit to avoid confusion. sctp_wmem is not used at all. Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Max Matveev <makc@redhat.com> Reviewed-by: Shan Wei <shanwei@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-06-08inetpeer: remove unused listEric Dumazet
Andi Kleen and Tim Chen reported huge contention on inetpeer unused_peers.lock, on memcached workload on a 40 core machine, with disabled route cache. It appears we constantly flip peers refcnt between 0 and 1 values, and we must insert/remove peers from unused_peers.list, holding a contended spinlock. Remove this list completely and perform a garbage collection on-the-fly, at lookup time, using the expired nodes we met during the tree traversal. This removes a lot of code, makes locking more standard, and obsoletes two sysctls (inet_peer_gc_mintime and inet_peer_gc_maxtime). This also removes two pointers in inet_peer structure. There is still a false sharing effect because refcnt is in first cache line of object [were the links and keys used by lookups are located], we might move it at the end of inet_peer structure to let this first cache line mostly read by cpus. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Andi Kleen <andi@firstfloor.org> CC: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-20tcp: document tcp_max_ssthresh (Limited Slow-Start)Ilpo Järvinen
Base on Ilpo's patch about documenting tcp_max_ssthresh. (see http://marc.info/?l=linux-netdev&m=117950581307310&w=2) According to errata of RFC3742, fix the number of segments increased during RTT time. Just to state the occasion to use this parameter, But about how to set parameter value, maybe some others can do it. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-02-02tcp_ecn is an integer not a booleanPeter Chubb
There was some confusion at LCA as to why the sysctl tcp_ecn took one of three values when it was documented as a Boolean. This patch fixes the documentation. Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-13net: change ip_default_ttl documentationEric Dumazet
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-12-08Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/ath/ath9k/ar9003_eeprom.c net/llc/af_llc.c
2010-11-28tcp: restrict net.ipv4.tcp_adv_win_scale (#20312)Alexey Dobriyan
tcp_win_from_space() does the following: if (sysctl_tcp_adv_win_scale <= 0) return space >> (-sysctl_tcp_adv_win_scale); else return space - (space >> sysctl_tcp_adv_win_scale); "space" is int. As per C99 6.5.7 (3) shifting int for 32 or more bits is undefined behaviour. Indeed, if sysctl_tcp_adv_win_scale is exactly 32, space >> 32 equals space and function returns 0. Which means we busyloop in tcp_fixup_rcvbuf(). Restrict net.ipv4.tcp_adv_win_scale to [-31, 31]. Fix https://bugzilla.kernel.org/show_bug.cgi?id=20312 Steps to reproduce: echo 32 >/proc/sys/net/ipv4/tcp_adv_win_scale wget www.kernel.org [softlockup] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-17clarify documentation for net.ipv4.igmp_max_membershipsJeremy Eder
This patch helps clarify documentation for net.ipv4.igmp_max_memberships by providing a formula for calculating the maximum number of multicast groups that can be subscribed to, plus defining the theoretical limit. Signed-off-by: Jiri Pirko <jpirko@redhat.com> Signed-off-by: Jeremy Eder <jeder@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-12docs: Add neigh/gc_thresh3 and route/max_size documentation.Ben Greear
Signed-off-by: Ben Greear <greearb@candelatech.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-03ipv6: Update ip-sysctl.txt documentation for recent changes to accept_ra and ↵Thomas Graf
forwarding Documentation for recent changes to the tunables accept_ra and forwarding. Signed-off-by: Thomas Graf <tgraf@infradead.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-31arp_notify: document that a gratuitous ARP request is sent when this option ↵Ian Campbell
is enabled This option causes a gratuitous ARP request, not a reply as the documentation currently suggests. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Stephen Hemminger <shemminger@linux-foundation.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: David S. Miller <davem@davemloft.net> Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-15net: reserve ports for applications using fixed port numbersAmerigo Wang
(Dropped the infiniband part, because Tetsuo modified the related code, I will send a separate patch for it once this is accepted.) This patch introduces /proc/sys/net/ipv4/ip_local_reserved_ports which allows users to reserve ports for third-party applications. The reserved ports will not be used by automatic port assignments (e.g. when calling connect() or bind() with port number 0). Explicit port allocation behavior is unchanged. Signed-off-by: Octavian Purdila <opurdila@ixiacom.com> Signed-off-by: WANG Cong <amwang@redhat.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-02-25Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
2010-02-23IPv6: better document max_addresses parameterBrian Haley
Andrew Morton wrote: >> >From ip-sysctl.txt file in kernel documentation I can see following description >> for max_addresses: >> max_addresses - INTEGER >> Number of maximum addresses per interface. 0 disables limitation. >> It is recommended not set too large value (or 0) because it would >> be too easy way to crash kernel to allow to create too much of >> autoconfigured addresses. ^^^^^^^^^^^^^^ >> If this parameter applies only for auto-configured IP addressed, please state >> it more clearly in docs or rename the parameter to show that it refers to >> auto-configuration. It did mention autoconfigured in the text, but the below makes it more obvious. More clearly document IPv6 max_addresses parameter. Signed-off-by: Brian Haley <brian.haley@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-02-18net: TCP thin dupackAndreas Petlund
This patch enables fast retransmissions after one dupACK for TCP if the stream is identified as thin. This will reduce latencies for thin streams that are not able to trigger fast retransmissions due to high packet interarrival time. This mechanism is only active if enabled by iocontrol or syscontrol and the stream is identified as thin. Signed-off-by: Andreas Petlund <apetlund@simula.no> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-02-18net: TCP thin linear timeoutsAndreas Petlund
This patch will make TCP use only linear timeouts if the stream is thin. This will help to avoid the very high latencies that thin stream suffer because of exponential backoff. This mechanism is only active if enabled by iocontrol or syscontrol and the stream is identified as thin. A maximum of 6 linear timeouts is tried before exponential backoff is resumed. Signed-off-by: Andreas Petlund <apetlund@simula.no> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-19ipv4: allow warming up the ARP cache with request type gratuitous ARPOctavian Purdila
If the per device ARP_ACCEPT option is enable, currently we only allow creating new ARP cache entries for response type gratuitous ARP. Allowing gratuitous ARP to create new ARP entries (not only to update existing ones) is useful when we want to avoid unnecessary delays for the first packet of a stream. This patch allows request type gratuitous ARP to create new ARP cache entries as well. This is useful when we want to populate the ARP cache entries for a large number of hosts on the same LAN. Signed-off-by: Octavian Purdila <opurdila@ixiacom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-07net: RFC3069, private VLAN proxy arp supportJesper Dangaard Brouer
This is to be used together with switch technologies, like RFC3069, that where the individual ports are not allowed to communicate with each other, but they are allowed to talk to the upstream router. As described in RFC 3069, it is possible to allow these hosts to communicate through the upstream router by proxy_arp'ing. This patch basically allow proxy arp replies back to the same interface (from which the ARP request/solicitation was received). Tunable per device via proc "proxy_arp_pvlan": /proc/sys/net/ipv4/conf/*/proxy_arp_pvlan This switch technology is known by different vendor names: - In RFC 3069 it is called VLAN Aggregation. - Cisco and Allied Telesyn call it Private VLAN. - Hewlett-Packard call it Source-Port filtering or port-isolation. - Ericsson call it MAC-Forced Forwarding (RFC Draft). Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-03ipv4 05/05: add sysctl to accept packets with local source addressesPatrick McHardy
commit 8ec1e0ebe26087bfc5c0394ada5feb5758014fc8 Author: Patrick McHardy <kaber@trash.net> Date: Thu Dec 3 12:16:35 2009 +0100 ipv4: add sysctl to accept packets with local source addresses Change fib_validate_source() to accept packets with a local source address when the "accept_local" sysctl is set for the incoming inet device. Combined with the previous patches, this allows to communicate between multiple local interfaces over the wire. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-02TCPCT part 1c: sysctl_tcp_cookie_size, socket option TCP_COOKIE_TRANSACTIONSWilliam Allen Simpson
Define sysctl (tcp_cookie_size) to turn on and off the cookie option default globally, instead of a compiled configuration option. Define per socket option (TCP_COOKIE_TRANSACTIONS) for setting constant data values, retrieving variable cookie values, and other facilities. Move inline tcp_clear_options() unchanged from net/tcp.h to linux/tcp.h, near its corresponding struct tcp_options_received (prior to changes). This is a straightforward re-implementation of an earlier (year-old) patch that no longer applies cleanly, with permission of the original author (Adam Langley): http://thread.gmane.org/gmane.linux.network/102586 These functions will also be used in subsequent patches that implement additional features. Requires: net: TCP_MSS_DEFAULT, TCP_MSS_DESIRED Signed-off-by: William.Allen.Simpson@gmail.com Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-02Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6