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* [TCP]: Congestion control API update.Stephen Hemminger2007-04-26
| | | | | | | | | | | Do some simple changes to make congestion control API faster/cleaner. * use ktime_t rather than timeval * merge rtt sampling into existing ack callback this means one indirect call versus two per ack. * use flags bits to store options/settings Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Sed magic converts func(sk, tp, ...) -> func(sk, ...)Ilpo Järvinen2007-04-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is (mostly) automated change using magic: sed -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e 's|struct sock \*sk,[\n\t ]*struct tcp_sock \*tp\([^{]*\n{\n\)| struct sock \*sk\1\tstruct tcp_sock *tp = tcp_sk(sk);\n|g' -e 's|struct sock \*sk, struct tcp_sock \*tp| struct sock \*sk|g' -e 's|sk, tp\([^-]\)|sk\1|g' Fixed four unused variable (tp) warnings that were introduced. In addition, manually added newlines after local variables and tweaked function arguments positioning. $ gcc --version gcc (GCC) 4.1.1 20060525 (Red Hat 4.1.1-1) ... $ codiff -fV built-in.o.old built-in.o.new net/ipv4/route.c: rt_cache_flush | +14 1 function changed, 14 bytes added net/ipv4/tcp.c: tcp_setsockopt | -5 tcp_sendpage | -25 tcp_sendmsg | -16 3 functions changed, 46 bytes removed net/ipv4/tcp_input.c: tcp_try_undo_recovery | +3 tcp_try_undo_dsack | +2 tcp_mark_head_lost | -12 tcp_ack | -15 tcp_event_data_recv | -32 tcp_rcv_state_process | -10 tcp_rcv_established | +1 7 functions changed, 6 bytes added, 69 bytes removed, diff: -63 net/ipv4/tcp_output.c: update_send_head | -9 tcp_transmit_skb | +19 tcp_cwnd_validate | +1 tcp_write_wakeup | -17 __tcp_push_pending_frames | -25 tcp_push_one | -8 tcp_send_fin | -4 7 functions changed, 20 bytes added, 63 bytes removed, diff: -43 built-in.o.new: 18 functions changed, 40 bytes added, 178 bytes removed, diff: -138 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SK_BUFF]: Some more conversions to skb_copy_from_linear_dataArnaldo Carvalho de Melo2007-04-26
| | | | Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
* [SK_BUFF]: Convert skb->tail to sk_buff_data_tArnaldo Carvalho de Melo2007-04-26
| | | | | | | | | | | | | | | So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes on 64bit architectures, allowing us to combine the 4 bytes hole left by the layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4 64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN... :-) Many calculations that previously required that skb->{transport,network, mac}_header be first converted to a pointer now can be done directly, being meaningful as offsets or pointers. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SK_BUFF]: Introduce tcp_hdr(), remove skb->h.thArnaldo Carvalho de Melo2007-04-26
| | | | | Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: whitespace cleanupStephen Hemminger2007-04-26
| | | | | | | Add whitespace around keywords. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Abstract out all write queue operations.David S. Miller2007-04-26
| | | | | | | This allows the write queue implementation to be changed, for example, to one which allows fast interval searching. Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Add two new spurious RTO responses to FRTOIlpo Järvinen2007-04-26
| | | | | | | | | | | | | | | | | New sysctl tcp_frto_response is added to select amongst these responses: - Rate halving based; reuses CA_CWR state (default) - Very conservative; used to be the only one available (=1) - Undo cwr; undoes ssthresh and cwnd reductions (=2) The response with rate halving requires a new parameter to tcp_enter_cwr because FRTO has already reduced ssthresh and doing a second reduction there has to be prevented. In addition, to keep things nice on 80 cols screen, a local variable was added. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: slow_start_after_idle should influence cwnd validation tooDavid S. Miller2007-04-09
| | | | | | | | | | | | | | | | For the cases that slow_start_after_idle are meant to deal with, it is almost a certainty that the congestion window tests will think the connection is application limited and we'll thus decrease the cwnd there too. This defeats the whole point of setting slow_start_after_idle to zero. So test it there too. We do not cancel out the entire tcp_cwnd_validate() function so that if the sysctl is changed we still have the validation state maintained. Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Do receiver-side SWS avoidance for rcvbuf < MSS.John Heffner2007-04-02
| | | | | Signed-off-by: John Heffner <jheffner@psc.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Prevent pseudo garbage in SYN's advertized windowIlpo Järvinen2007-02-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | TCP may advertize up to 16-bits window in SYN packets (no window scaling allowed). At the same time, TCP may have rcv_wnd (32-bits) that does not fit to 16-bits without window scaling resulting in pseudo garbage into advertized window from the low-order bits of rcv_wnd. This can happen at least when mss <= (1<<wscale) (see tcp_select_initial_window). This patch fixes the handling of SYN advertized windows (compile tested only). In worst case (which is unlikely to occur though), the receiver advertized window could be just couple of bytes. I'm not sure that such situation would be handled very well at all by the receiver!? Fortunately, the situation normalizes after the first non-SYN ACK is received because it has the correct, scaled window. Alternatively, tcp_select_initial_window could be changed to prevent too large rcv_wnd in the first place. [ tcp_make_synack() has the same bug, and I've added a fix for that to this patch -DaveM ] Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET] IPV4: Fix whitespace errors.YOSHIFUJI Hideaki2007-02-11
| | | | | Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Don't apply FIN exception to full TSO segments.John Heffner2007-02-08
| | | | | Signed-off-by: John Heffner <jheffner@psc.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Restore SKB socket owner setting in tcp_transmit_skb().David S. Miller2007-01-26
| | | | | | | | | | | | | Revert 931731123a103cfb3f70ac4b7abfc71d94ba1f03 We can't elide the skb_set_owner_w() here because things like certain netfilter targets (such as owner MATCH) need a socket to be set on the SKB for correct operation. Thanks to Jan Engelhardt and other netfilter list members for pointing this out. Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: rare bad TCP checksum with 2.6.19Jarek Poplawski2007-01-24
| | | | | | | | | | | | | | The patch "Replace CHECKSUM_HW by CHECKSUM_PARTIAL/CHECKSUM_COMPLETE" changed to unconditional copying of ip_summed field from collapsed skb. This patch reverts this change. The majority of substantial work including heavy testing and diagnosing by: Michael Tokarev <mjt@tls.msk.ru> Possible reasons pointed by: Herbert Xu and Patrick McHardy. Signed-off-by: Jarek Poplawski <jarkao2@o2.pl> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: MD5 Signature Option (RFC2385) support.YOSHIFUJI Hideaki2006-12-03
| | | | | | | Based on implementation by Rick Payne. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP/DCCP]: Introduce net_xmit_evalGerrit Renker2006-12-03
| | | | | | | | | | | | Throughout the TCP/DCCP (and tunnelling) code, it often happens that the return code of a transmit function needs to be tested against NET_XMIT_CN which is a value that does not indicate a strict error condition. This patch uses a macro for these recurring situations which is consistent with the already existing macro net_xmit_errno, saving on duplicated code. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
* [TCP]: Don't set SKB owner in tcp_transmit_skb().David S. Miller2006-12-03
| | | | | | | | | | | | | | | | | | | | The data itself is already charged to the SKB, doing the skb_set_owner_w() just generates a lot of noise and extra atomics we don't really need. Lmbench improvements on lat_tcp are minimal: before: TCP latency using localhost: 23.2701 microseconds TCP latency using localhost: 23.1994 microseconds TCP latency using localhost: 23.2257 microseconds after: TCP latency using localhost: 22.8380 microseconds TCP latency using localhost: 22.9465 microseconds TCP latency using localhost: 22.8462 microseconds Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Bound TSO defer timeJohn Heffner2006-10-18
| | | | | | | | | | | | | | | | | | This patch limits the amount of time you will defer sending a TSO segment to less than two clock ticks, or the time between two acks, whichever is longer. On slow links, deferring causes significant bursts. See attached plots, which show RTT through a 1 Mbps link with a 100 ms RTT and ~100 ms queue for (a) non-TSO, (b) currnet TSO, and (c) patched TSO. This burstiness causes significant jitter, tends to overflow queues early (bad for short queues), and makes delay-based congestion control more difficult. Deferring by a couple clock ticks I believe will have a relatively small impact on performance. Signed-off-by: John Heffner <jheffner@psc.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Use hton{l,s}() for non-initializers.YOSHIFUJI Hideaki2006-10-12
| | | | | Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] net/ipv4/tcp_output.c: trivial annotationsAl Viro2006-09-28
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET/IPV4/IPV6]: Change some sysctl variables to __read_mostlyBrian Haley2006-09-22
| | | | | | | | | | Change net/core, ipv4 and ipv6 sysctl variables to __read_mostly. Couldn't actually measure any performance increase while testing (.3% I consider noise), but seems like the right thing to do. Signed-off-by: Brian Haley <brian.haley@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Replace CHECKSUM_HW by CHECKSUM_PARTIAL/CHECKSUM_COMPLETEPatrick McHardy2006-09-22
| | | | | | | | | | | Replace CHECKSUM_HW by CHECKSUM_PARTIAL (for outgoing packets, whose checksum still needs to be completed) and CHECKSUM_COMPLETE (for incoming packets, device supplied full checksum). Patch originally from Herbert Xu, updated by myself for 2.6.18-rc3. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Limit window scaling if window is clamped.Stephen Hemminger2006-08-22
| | | | | | | | | | | | | | | This small change allows for easy per-route workarounds for broken hosts or middleboxes that are not compliant with TCP standards for window scaling. Rather than having to turn off window scaling globally. This patch allows reducing or disabling window scaling if window clamp is present. Example: Mark Lord reported a problem with 2.6.17 kernel being unable to access http://www.everymac.com # ip route add 216.145.246.23/32 via 10.8.0.1 window 65535 Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: SNMPv2 tcpOutSegs counter errorWei Yongjun2006-08-08
| | | | | | | Do not count retransmitted segments. Signed-off-by: Wei Yongjun <yjwei@nanjing-fnst.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Generalise TSO-specific bits from skb_setup_capsHerbert Xu2006-06-30
| | | | | | | | | | | | | | This patch generalises the TSO-specific bits from sk_setup_caps by adding the sk_gso_type member to struct sock. This makes sk_setup_caps generic so that it can be used by TCPv6 or UFO. The only catch is that whoever uses this must provide a GSO implementation for their protocol which I think is a fair deal :) For now UFO continues to live without a GSO implementation which is OK since it doesn't use the sock caps field at the moment. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Add ECN support for TSOMichael Chan2006-06-29
| | | | | | | | | | | | | | | | | | | | | | | | | | In the current TSO implementation, NETIF_F_TSO and ECN cannot be turned on together in a TCP connection. The problem is that most hardware that supports TSO does not handle CWR correctly if it is set in the TSO packet. Correct handling requires CWR to be set in the first packet only if it is set in the TSO header. This patch adds the ability to turn on NETIF_F_TSO and ECN using GSO if necessary to handle TSO packets with CWR set. Hardware that handles CWR correctly can turn on NETIF_F_TSO_ECN in the dev-> features flag. All TSO packets with CWR set will have the SKB_GSO_TCPV4_ECN set. If the output device does not have the NETIF_F_TSO_ECN feature set, GSO will split the packet up correctly with CWR only set in the first segment. With help from Herbert Xu <herbert@gondor.apana.org.au>. Since ECN can always be enabled with TSO, the SOCK_NO_LARGESEND sock flag is completely removed. Signed-off-by: Michael Chan <mchan@broadcom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [NET]: Merge TSO/UFO fields in sk_buffHerbert Xu2006-06-23
| | | | | | | | | | | | | | | | | | | | | | | | Having separate fields in sk_buff for TSO/UFO (tso_size/ufo_size) is not going to scale if we add any more segmentation methods (e.g., DCCP). So let's merge them. They were used to tell the protocol of a packet. This function has been subsumed by the new gso_type field. This is essentially a set of netdev feature bits (shifted by 16 bits) that are required to process a specific skb. As such it's easy to tell whether a given device can process a GSO skb: you just have to and the gso_type field and the netdev's features field. I've made gso_type a conjunction. The idea is that you have a base type (e.g., SKB_GSO_TCPV4) that can be modified further to support new features. For example, if we add a hardware TSO type that supports ECN, they would declare NETIF_F_TSO | NETIF_F_TSO_ECN. All TSO packets with CWR set would have a gso_type of SKB_GSO_TCPV4 | SKB_GSO_TCPV4_ECN while all other TSO packets would be SKB_GSO_TCPV4. This means that only the CWR packets need to be emulated in software. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Add tcp_slow_start_after_idle sysctl.David S. Miller2006-06-18
| | | | | | | A lot of people have asked for a way to disable tcp_cwnd_restart(), and it seems reasonable to add a sysctl to do that. Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Avoid skb_pull if possible when trimming headHerbert Xu ~{PmVHI~}2006-06-05
| | | | | | | | | | | | | | | | | | | | | | Trimming the head of an skb by calling skb_pull can cause the packet to become unaligned if the length pulled is odd. Since the length is entirely arbitrary for a FIN packet carrying data, this is actually quite common. Unaligned data is not the end of the world, but we should avoid it if it's easily done. In this case it is trivial. Since we're discarding all of the head data it doesn't matter whether we move skb->data forward or back. However, it is still possible to have unaligned skb->data in general. So network drivers should be prepared to handle it instead of crashing. This patch also adds an unlikely marking on len < headlen since partial ACKs on head data are extremely rare in the wild. As the return value of __pskb_trim_head is no longer ever NULL that has been removed. Signed-off-by: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Fix unlikely usage in tcp_transmit_skb()Hua Zhong2006-04-29
| | | | | | | | | The following unlikely should be replaced by likely because the condition happens every time unless there is a hard error to transmit a packet. Signed-off-by: Hua Zhong <hzhong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Account skb overhead in tcp_fragmentHerbert Xu2006-04-20
| | | | | | | | | | | Make sure that we get the full sizeof(struct sk_buff) plus the data size accounted for in skb->truesize. This will create invariants that will allow adding assertion checks on skb->truesize. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Fix truesize underflowHerbert Xu2006-04-18
| | | | | | | | | | | | | | | | | | There is a problem with the TSO packet trimming code. The cause of this lies in the tcp_fragment() function. When we allocate a fragment for a completely non-linear packet the truesize is calculated for a payload length of zero. This means that truesize could in fact be less than the real payload length. When that happens the TSO packet trimming can cause truesize to become negative. This in turn can cause sk_forward_alloc to be -n * PAGE_SIZE which would trigger the warning. I've copied the code DaveM used in tso_fragment which should work here. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IPV4]: Possible cleanups.Adrian Bunk2006-04-14
| | | | | | | | | | | | | | | | | | | This patch contains the following possible cleanups: - make the following needlessly global function static: - arp.c: arp_rcv() - remove the following unused EXPORT_SYMBOL's: - devinet.c: devinet_ioctl - fib_frontend.c: ip_rt_ioctl - inet_hashtables.c: inet_bind_bucket_create - inet_hashtables.c: inet_bind_hash - tcp_input.c: sysctl_tcp_abc - tcp_ipv4.c: sysctl_tcp_tw_reuse - tcp_output.c: sysctl_tcp_mtu_probing - tcp_output.c: sysctl_tcp_base_mss Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: sysctl to allow TCP window > 32767 sans wscaleRick Jones2006-03-21
| | | | | | | | | | | | | | | | Back in the dark ages, we had to be conservative and only allow 15-bit window fields if the window scale option was not negotiated. Some ancient stacks used a signed 16-bit quantity for the window field of the TCP header and would get confused. Those days are long gone, so we can use the full 16-bits by default now. There is a sysctl added so that we can still interact with such old stacks Signed-off-by: Rick Jones <rick.jones2@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] mtu probing: move tcp-specific data out of inet_connection_sockJohn Heffner2006-03-21
| | | | | | | | This moves some TCP-specific MTU probing state out of inet_connection_sock back to tcp_sock. Signed-off-by: John Heffner <jheffner@psc.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: MTU probingJohn Heffner2006-03-20
| | | | | | | | | Implementation of packetization layer path mtu discovery for TCP, based on the internet-draft currently found at <http://www.ietf.org/internet-drafts/draft-ietf-pmtud-method-05.txt>. Signed-off-by: John Heffner <jheffner@psc.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Fix tcp_tso_should_defer() when limit>=65536David S. Miller2006-03-11
| | | | | | | | | | That's >= a full sized TSO frame, so we should always return 0 in that case. Based upon a report and initial patch from Lachlan Andrew, final patch suggested by Herbert Xu. Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: less inline'sStephen Hemminger2006-01-03
| | | | | | | | | | | | | | | | | | | | | TCP inline usage cleanup: * get rid of inline in several places * replace __inline__ with inline where possible * move functions used in one file out of tcp.h * let compiler decide on used once cases On x86_64: text data bss dec hex filename 3594701 648348 567400 4810449 4966d1 vmlinux.orig 3593133 648580 567400 4809113 496199 vmlinux On sparc64: text data bss dec hex filename 2538278 406152 530392 3474822 350586 vmlinux.ORIG 2536382 406384 530392 3473158 34ff06 vmlinux Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [IP_SOCKGLUE]: Remove most of the tcp specific callsArnaldo Carvalho de Melo2006-01-03
| | | | | | | | | | | | | | As DCCP needs to be called in the same spots. Now we have a member in inet_sock (is_icsk), set at sock creation time from struct inet_protosw->flags (if INET_PROTOSW_ICSK is set, like for TCP and DCCP) to see if a struct sock instance is a inet_connection_sock for places like the ones in ip_sockglue.c (v4 and v6) where we previously were looking if sk_type was SOCK_STREAM, that is insufficient because we now use the same code for DCCP, that has sk_type SOCK_DCCP. Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [ICSK]: Rename struct tcp_func to struct inet_connection_sock_af_opsArnaldo Carvalho de Melo2006-01-03
| | | | | | | | And move it to struct inet_connection_sock. DCCP will use it in the upcoming changesets. Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP] Vegas: timestamp before cloneDavid S. Miller2005-12-06
| | | | | | | | | | | | | We have to store the congestion control timestamp on the SKB before we clone it, not after. Else we get no timestamping information at all. tcp_transmit_skb() has been reworked so that we can do the timestamp still in one spot, instead of at all the call sites. Problem discovered, and initial fix, from Tom Young <tyo@ee.unimelb.edu.au>. Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: speed up SACK processingStephen Hemminger2005-11-10
| | | | | | | | | 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>
* [TCP]: spelling fixesStephen Hemminger2005-11-10
| | | | | | | Minor spelling fixes for TCP code. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: fix congestion window update when using TSO deferalStephen Hemminger2005-11-10
| | | | | | | | | | | | | | | | | 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>
* [TCP] Allow len == skb->len in tcp_fragmentHerbert Xu2005-10-20
| | | | | | | | | It is legitimate to call tcp_fragment with len == skb->len since that is done for FIN packets and the FIN flag counts as one byte. So we should only check for the len > skb->len case. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
* [TCP]: Ratelimit debugging warning.Herbert Xu2005-10-13
| | | | | | | Better safe than sorry. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [TCP]: Add code to help track down "BUG at net/ipv4/tcp_output.c:438!"Herbert Xu2005-10-12
| | | | | | | | | | | | | | This is the second report of this bug. Unfortunately the first reporter hasn't been able to reproduce it since to provide more debugging info. So let's apply this patch for 2.6.14 to 1) Make this non-fatal. 2) Provide the info we need to track it down. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] gfp flags annotations - part 1Al Viro2005-10-08
| | | | | | | | | | | | - added typedef unsigned int __nocast gfp_t; - replaced __nocast uses for gfp flags with gfp_t - it gives exactly the same warnings as far as sparse is concerned, doesn't change generated code (from gcc point of view we replaced unsigned int with typedef) and documents what's going on far better. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [TCP]: Revert 6b251858d377196b8cea20e65cae60f584a42735David S. Miller2005-09-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | But retain the comment fix. Alexey Kuznetsov has explained the situation as follows: -------------------- I think the fix is incorrect. Look, the RFC function init_cwnd(mss) is not continuous: f.e. for mss=1095 it needs initial window 1095*4, but for mss=1096 it is 1096*3. We do not know exactly what mss sender used for calculations. If we advertised 1096 (and calculate initial window 3*1096), the sender could limit it to some value < 1096 and then it will need window his_mss*4 > 3*1096 to send initial burst. See? So, the honest function for inital rcv_wnd derived from tcp_init_cwnd() is: init_rcv_wnd(mss)= min { init_cwnd(mss1)*mss1 for mss1 <= mss } It is something sort of: if (mss < 1096) return mss*4; if (mss < 1096*2) return 1096*4; return mss*2; (I just scrablled a graph of piece of paper, it is difficult to see or to explain without this) I selected it differently giving more window than it is strictly required. Initial receive window must be large enough to allow sender following to the rfc (or just setting initial cwnd to 2) to send initial burst. But besides that it is arbitrary, so I decided to give slack space of one segment. Actually, the logic was: If mss is low/normal (<=ethernet), set window to receive more than initial burst allowed by rfc under the worst conditions i.e. mss*4. This gives slack space of 1 segment for ethernet frames. For msses slighlty more than ethernet frame, take 3. Try to give slack space of 1 frame again. If mss is huge, force 2*mss. No slack space. Value 1460*3 is really confusing. Minimal one is 1096*2, but besides that it is an arbitrary value. It was meant to be ~4096. 1460*3 is just the magic number from RFC, 1460*3 = 1095*4 is the magic :-), so that I guess hands typed this themselves. -------------------- Signed-off-by: David S. Miller <davem@davemloft.net>
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