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* [TCP]: Limit processing lost_retrans loop to work-to-do casesIlpo Järvinen2007-10-11
| | | | | | | | | This addition of lost_retrans_low to tcp_sock might be unnecessary, it's not clear how often lost_retrans worker is executed when there wasn't work to do. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Fix lost_retrans loop vs fastpath problemsIlpo Järvinen2007-10-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Detection implemented with lost_retrans must work also when fastpath is taken, yet most of the queue is skipped including (very likely) those retransmitted skb's we're interested in. This problem appeared when the hints got added, which removed a need to always walk over the whole write queue head. Therefore decicion for the lost_retrans worker loop entry must be separated from the sacktag processing more than it was necessary before. It turns out to be problematic to optimize the worker loop very heavily because ack_seqs of skb may have a number of discontinuity points. Maybe similar approach as currently is implemented could be attempted but that's becoming more and more complex because the trend is towards less skb walking in sacktag marker. Trying a simple work until all rexmitted skbs heve been processed approach. Maybe after(highest_sack_end_seq, tp->high_seq) checking is not sufficiently accurate and causes entry too often in no-work-to-do cases. Since that's not known, I've separated solution to that from this patch. Noticed because of report against a related problem from TAKANO Ryousei <takano@axe-inc.co.jp>. He also provided a patch to that part of the problem. This patch includes solution to it (though this patch has to use somewhat different placement). TAKANO's description and patch is available here: http://marc.info/?l=linux-netdev&m=119149311913288&w=2 ...In short, TAKANO's problem is that end_seq the loop is using not necessarily the largest SACK block's end_seq because the current ACK may still have higher SACK blocks which are later by the loop. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: No need to re-count fackets_out/sacked_out at RTOIlpo Järvinen2007-10-11
| | | | | | | | | | Both sacked_out and fackets_out are directly known from how parameter. Since fackets_out is accurate, there's no need for recounting (sacked_out was previously unnecessarily counted in the loop anyway). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Extract tcp_match_queue_to_sack from sacktag codeIlpo Järvinen2007-10-11
| | | | | | | | | | | This is necessary for upcoming DSACK bugfix. Reduces sacktag length which is not very sad thing at all... :-) Notice that there's a need to handle out-of-mem at caller's place. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Kill almost unused variable pcount from sacktagIlpo Järvinen2007-10-11
| | | | | | | It's on the way for future cutting of that function. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Fix mark_head_lost to ignore R-bit when trying to mark LIlpo Järvinen2007-10-11
| | | | | | | | | | This condition (plain R) can arise at least in recovery that is triggered after tcp_undo_loss. There isn't any reason why they should not be marked as lost, not marking makes in_flight estimator to return too large values. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Add bytes_acked (ABC) clearing to FRTO tooIlpo Järvinen2007-10-11
| | | | | | | | | | | | | | | | I was reading tcp_enter_loss while looking for Cedric's bug and noticed bytes_acked adjustment is missing from FRTO side. Since bytes_acked will only be used in tcp_cong_avoid, I think it's safe to assume RTO would be spurious. During FRTO cwnd will be not controlled by tcp_cong_avoid and if FRTO calls for conventional recovery, cwnd is adjusted and the result of wrong assumption is cleared from bytes_acked. If RTO was in fact spurious, we did normal ABC already and can continue without any additional adjustments. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETLINK]: fib_frontend build fixesDavid S. Miller2007-10-11
| | | | | | | | | 1) fibnl needs to be declared outside of config ifdefs, and also should not be explicitly initialized to NULL 2) nl_fib_input() args are wrong for netlink_kernel_create() input method Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: make netlink user -> kernel interface synchroniousDenis V. Lunev2007-10-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch make processing netlink user -> kernel messages synchronious. This change was inspired by the talk with Alexey Kuznetsov about current netlink messages processing. He says that he was badly wrong when introduced asynchronious user -> kernel communication. The call netlink_unicast is the only path to send message to the kernel netlink socket. But, unfortunately, it is also used to send data to the user. Before this change the user message has been attached to the socket queue and sk->sk_data_ready was called. The process has been blocked until all pending messages were processed. The bad thing is that this processing may occur in the arbitrary process context. This patch changes nlk->data_ready callback to get 1 skb and force packet processing right in the netlink_unicast. Kernel -> user path in netlink_unicast remains untouched. EINTR processing for in netlink_run_queue was changed. It forces rtnl_lock drop, but the process remains in the cycle until the message will be fully processed. So, there is no need to use this kludges now. Signed-off-by: Denis V. Lunev <den@openvz.org> Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
* [INET]: local port range robustnessStephen Hemminger2007-10-10
| | | | | | | | | | | | | | | Expansion of original idea from Denis V. Lunev <den@openvz.org> Add robustness and locking to the local_port_range sysctl. 1. Enforce that low < high when setting. 2. Use seqlock to ensure atomic update. The locking might seem like overkill, but there are cases where sysadmin might want to change value in the middle of a DoS attack. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC]: Move IP protocol setting from transforms into xfrm4_input.cHerbert Xu2007-10-10
| | | | | | | | | This patch makes the IPv4 x->type->input functions return the next protocol instead of setting it directly. This is identical to how we do things in IPv6 and will help us merge common code on the input path. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC]: Move IP length/checksum setting out of transformsHerbert Xu2007-10-10
| | | | | | | | | | | | This patch moves the setting of the IP length and checksum fields out of the transforms and into the xfrmX_output functions. This would help future efforts in merging the transforms themselves. It also adds an optimisation to ipcomp due to the fact that the transport offset is guaranteed to be zero. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC]: Get rid of ipv6_{auth,esp,comp}_hdrHerbert Xu2007-10-10
| | | | | | | | | | | | | This patch removes the duplicate ipv6_{auth,esp,comp}_hdr structures since they're identical to the IPv4 versions. Duplicating them would only create problems for ourselves later when we need to add things like extended sequence numbers. I've also added transport header type conversion headers for these types which are now used by the transforms. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC]: Use IPv6 calling convention as the convention for x->mode->outputHerbert Xu2007-10-10
| | | | | | | | | | | | | The IPv6 calling convention for x->mode->output is more general and could help an eventual protocol-generic x->type->output implementation. This patch adopts it for IPv4 as well and modifies the IPv4 type output functions accordingly. It also rewrites the IPv6 mac/transport header calculation to be based off the network header where practical. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC]: Set skb->data to payload in x->mode->outputHerbert Xu2007-10-10
| | | | | | | | | | | | | | | | This patch changes the calling convention so that on entry from x->mode->output and before entry into x->type->output skb->data will point to the payload instead of the IP header. This is essentially a redistribution of skb_push/skb_pull calls with the aim of minimising them on the common path of tunnel + ESP. It'll also let us use the same calling convention between IPv4 and IPv6 with the next patch. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC] esp: Remove NAT-T checksum invalidation for BEETHerbert Xu2007-10-10
| | | | | | | | | | | | I pointed this out back when this patch was first proposed but it looks like it got lost along the way. The checksum only needs to be ignored for NAT-T in transport mode where we lose the original inner addresses due to NAT. With BEET the inner addresses will be intact so the checksum remains valid. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Separate lost_retrans loop into own functionIlpo Järvinen2007-10-10
| | | | | | | | | | | | Follows own function for each task principle, this is really somewhat separate task being done in sacktag. Also reduces indentation. In addition, added ack_seq local var to break some long lines & fixed coding style things. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETFILTER]: Make netfilter code use the seq_open_privatePavel Emelyanov2007-10-10
| | | | | | | | | | Just switch to the consolidated calls. ipt_recent() has to initialize the private, so use the __seq_open_private() helper. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Make core networking code use seq_open_privatePavel Emelyanov2007-10-10
| | | | | | | | | | | This concerns the ipv4 and ipv6 code mostly, but also the netlink and unix sockets. The netlink code is an example of how to use the __seq_open_private() call - it saves the net namespace on this private. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC]: Move state lock into x->type->outputHerbert Xu2007-10-10
| | | | | | | | | | | This patch releases the lock on the state before calling x->type->output. It also adds the lock to the spots where they're currently needed. Most of those places (all except mip6) are expected to disappear with async crypto. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC]: Store IPv6 nh pointer in mac_header on outputHerbert Xu2007-10-10
| | | | | | | | | | | | | | | | | | | | Current the x->mode->output functions store the IPv6 nh pointer in the skb network header. This is inconvenient because the network header then has to be fixed up before the packet can leave the IPsec stack. The mac header field is unused on output so we can use that to store this instead. This patch does that and removes the network header fix-up in xfrm_output. It also uses ipv6_hdr where appropriate in the x->type->output functions. There is also a minor clean-up in esp4 to make it use the same code as esp6 to help any subsequent effort to merge the two. Lastly it kills two redundant skb_set_* statements in BEET that were simply copied over from transport mode. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC]: Move output replay code into xfrm_outputHerbert Xu2007-10-10
| | | | | | | | | | The replay counter is one of only two remaining things in the output code that requires a lock on the xfrm state (the other being the crypto). This patch moves it into the generic xfrm_output so we can remove the lock from the transforms themselves. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC]: Move common output code to xfrm_outputHerbert Xu2007-10-10
| | | | | | | | | | | | Most of the code in xfrm4_output_one and xfrm6_output_one are identical so this patch moves them into a common xfrm_output function which will live in net/xfrm. In fact this would seem to fix a bug as on IPv4 we never reset the network header after a transform which may upset netfilter later on. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC] ah: Remove keys from ah_data structureHerbert Xu2007-10-10
| | | | | | | | | The keys are only used during initialisation so we don't need to carry them in esp_data. Since we don't have to allocate them again, there is no need to place a limit on the authentication key length anymore. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPSEC] esp: Remove keys from esp_data structureHerbert Xu2007-10-10
| | | | | | | | | | | The keys are only used during initialisation so we don't need to carry them in esp_data. Since we don't have to allocate them again, there is no need to place a limit on the authentication key length anymore. This patch also kills the unused auth.icv member. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: sparse warning fixesStephen Hemminger2007-10-10
| | | | | | | | | Fix a bunch of sparse warnings. Mostly about 0 used as NULL pointer, and shadowed variable declarations. One notable case was that hash size should have been unsigned. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: "Annotate" another fackets_out state resetIlpo Järvinen2007-10-10
| | | | | | | | This should no longer be necessary because fackets_out is accurate. It indicates bugs elsewhere, thus report it. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Fix two off-by-one errors in fackets_out adjusting logicIlpo Järvinen2007-10-10
| | | | | | | | | | | | | | | | 1) Passing wrong skb to tcp_adjust_fackets_out could corrupt fastpath_cnt_hint as tcp_skb_pcount(next_skb) is not included to it if hint points exactly to the next_skb (it's lagging behind, see sacktag). 2) When fastpath_skb_hint is put backwards to avoid dangling skb reference, the skb's pcount must also be removed from count (not included like above). Reported by Cedric Le Goater <legoater@free.fr> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Wrap-safed reordering detection FRTO checkIlpo Järvinen2007-10-10
| | | | | | | | | In case somebody has a suggestion about a better place for this check, which must guarantee execution "early enough" (i.e, before the wrap can occur), I'm very open to them. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Update comment of SACK block validatorIlpo Järvinen2007-10-10
| | | | | | | | | | | | | Just came across what RFC2018 states about generation of valid SACK blocks in case of reneging. Alter comment a bit to point out clearly. IMHO, there isn't any reason to change code because the validation is there for a purpose (counters will inform user about decision TCP made if this case ever surfaces). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: fix comments that got messed up during code moveIlpo Järvinen2007-10-10
| | | | | Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: No fackets_out/highest_sack tuning when SACK isn't enabledIlpo Järvinen2007-10-10
| | | | | | | | This was found due to bug report from Cedric Le Goater though it turned this turned out to be unrelated bug. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETFILTER]: ctnetlink: use netlink policyPatrick McHardy2007-10-10
| | | | | Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETFILTER]: nfnetlink: rename functions containing 'nfattr'Patrick McHardy2007-10-10
| | | | | | | There is no struct nfattr anymore, rename functions to 'nlattr'. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NETFILTER]: nfnetlink: convert to generic netlink attribute functionsPatrick McHardy2007-10-10
| | | | | | | | | Get rid of the duplicated rtnetlink macros and use the generic netlink attribute functions. The old duplicated stuff is moved to a new header file that exists just for userspace. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Move hardware header operations out of netdevice.Stephen Hemminger2007-10-10
| | | | | | | | | Since hardware header operations are part of the protocol class not the device instance, make them into a separate object and save memory. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Wrap hard_header_parseStephen Hemminger2007-10-10
| | | | | | | | Wrap the hard_header_parse function to simplify next step of header_ops conversion. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Wrap netdevice hardware header creation.Stephen Hemminger2007-10-10
| | | | | | | | | | Add inline for common usage of hardware header creation, and fix bug in IPV6 mcast where the assumption about negative return is an errno. Negative return from hard_header means not enough space was available,(ie -N bytes). Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Make the loopback device per network namespace.Eric W. Biederman2007-10-10
| | | | | | | | | | | | | | | | This patch makes loopback_dev per network namespace. Adding code to create a different loopback device for each network namespace and adding the code to free a loopback device when a network namespace exits. This patch modifies all users the loopback_dev so they access it as init_net.loopback_dev, keeping all of the code compiling and working. A later pass will be needed to update the users to use something other than the initial network namespace. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPV4]: When possible test for IFF_LOOPBACK and not dev == loopback_devEric W. Biederman2007-10-10
| | | | | | | | | | Now that multiple loopback devices are becoming possible it makes the code a little cleaner and more maintainable to test if a deivice is th a loopback device by testing dev->flags & IFF_LOOPBACK instead of dev == loopback_dev. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPV4]: Remove unnecessary test for the loopback device from inetdev_destroyEric W. Biederman2007-10-10
| | | | | | | | | | | | | | Currently we never call unregister_netdev for the loopback device so it is impossible for us to reach inetdev_destroy with the loopback device. So the test in inetdev_destroy is unnecessary. Further when testing with my network namespace patches removing unregistering the loopback device and calling inetdev_destroy works fine so there appears to be no reason for avoiding unregistering the loopback device. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] MIB: Count FRTO's successfully detected spurious RTOsIlpo Järvinen2007-10-10
| | | | | Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Reordered ACK's (old) SACKs not included to discarded MIBIlpo Järvinen2007-10-10
| | | | | | | | | | | | | | | | | | | In case of ACK reordering, the SACK block might be valid in it's time but is already obsoleted since we've received another kind of confirmation about arrival of the segments through snd_una advancement of an earlier packet. I didn't bother to build distinguishing of valid and invalid SACK blocks but simply made reordered SACK blocks that are too old always not counted regardless of their "real" validity which could be determined by using the ack field of the reordered packet (won't be significant IMHO). DSACKs can very well be considered useful even in this situation, so won't do any of this for them. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Re-place highest_sack check to a more robust positionIlpo Järvinen2007-10-10
| | | | | | | | | | I previously added checking to position that is rather poor as state has already been adjusted quite a bit. Re-placing it above all state changes should be more robust though the return should never ever get executed regardless of its place :-). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Dynamically allocate the loopback device, part 1.Daniel Lezcano2007-10-10
| | | | | | | | | | | | | This patch replaces all occurences to the static variable loopback_dev to a pointer loopback_dev. That provides the mindless, trivial, uninteressting change part for the dynamic allocation for the loopback. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Acked-By: Kirill Korotaev <dev@sw.ru> Acked-by: Benjamin Thery <benjamin.thery@bull.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Avoid clearing sacktag hint in trivial situationsIlpo Järvinen2007-10-10
| | | | | | | | | | There's no reason to clear the sacktag skb hint when small part of the rexmit queue changes. Account changes (if any) instead when fragmenting/collapsing. RTO/FRTO do not touch SACKED_ACKED bits so no need to discard SACK tag hint at all. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Enable SACK enhanced FRTO (RFC4138) by defaultIlpo Järvinen2007-10-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most of the description that follows comes from my mail to netdev (some editing done): Main obstacle to FRTO use is its deployment as it has to be on the sender side where as wireless link is often the receiver's access link. Take initiative on behalf of unlucky receivers and enable it by default in future Linux TCP senders. Also IETF seems to interested in advancing FRTO from experimental [1]. How does FRTO help? =================== FRTO detects spurious RTOs and avoids a number of unnecessary retransmissions and a couple of other problems that can arise due to incorrect guess made at RTO (i.e., that segments were lost when they actually got delayed which is likely to occur e.g. in wireless environments with link-layer retransmission). Though FRTO cannot prevent the first (potentially unnecessary) retransmission at RTO, I suspect that it won't cost that much even if you have to pay for each bit (won't be that high percentage out of all packets after all :-)). However, usually when you have a spurious RTO, not only the first segment unnecessarily retransmitted but the *whole window*. It goes like this: all cumulative ACKs got delayed due to in-order delivery, then TCP will actually send 1.5*original cwnd worth of data in the RTO's slow-start when the delayed ACKs arrive (basically the original cwnd worth of it unnecessarily). In case one is interested in minimizing unnecessary retransmissions e.g. due to cost, those rexmissions must never see daylight. Besides, in the worst case the generated burst overloads the bottleneck buffers which is likely to significantly delay the further progress of the flow. In case of ll rexmissions, ACK compression often occurs at the same time making the burst very "sharp edged" (in that case TCP often loses most of the segments above high_seq => very bad performance too). When FRTO is enabled, those unnecessary retransmissions are fully avoided except for the first segment and the cwnd behavior after detected spurious RTO is determined by the response (one can tune that by sysctl). Basic version (non-SACK enhanced one), FRTO can fail to detect spurious RTO as spurious and falls back to conservative behavior. ACK lossage is much less significant than reordering, usually the FRTO can detect spurious RTO if at least 2 cumulative ACKs from original window are preserved (excluding the ACK that advances to high_seq). With SACK-enhanced version, the detection is quite robust. FRTO should remove the need to set a high lower bound for the RTO estimator due to delay spikes that occur relatively common in some environments (esp. in wireless/cellular ones). [1] http://www1.ietf.org/mail-archive/web/tcpm/current/msg02862.html Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] FRTO: Improve interoperability with other undo_marker usersIlpo Järvinen2007-10-10
| | | | | | | | | | | | | | | | Basically this change enables it, previously other undo_marker users were left with nothing. Reverse undo_marker logic completely to get it set right in CA_Loss. On the other hand, when spurious RTO is detected, clear it. Clearing might be too heavy for some scenarios but seems safe enough starting point for now and shouldn't have much effect except in majority of cases (if in any). By adding a new FLAG_ we avoid looping through write_queue when RTO occurs. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Cleanup tcp_tso_acked and tcp_clean_rtx_queueIlpo Järvinen2007-10-10
| | | | | | | | | | | | | | | | Implements following cleanups: - Comment re-placement (CodingStyle) - tcp_tso_acked() local (wrapper-like) variable removal (readability) - __-types removed (IMHO they make local variables jumpy looking and just was space) - acked -> flag (naming conventions elsewhere in TCP code) - linebreak adjustments (readability) - nested if()s combined (reduced indentation) - clarifying newlines added Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Move accounting from tso_acked to clean_rtx_queueIlpo Järvinen2007-10-10
| | | | | | | | | | | | The accounting code is pretty much the same, so it's a shame we do it in two places. I'm not too sure if added fully_acked check in MTU probing is really what we want perhaps the added end_seq could be used in the after() comparison. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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