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2005-10-12[TCP]: Add code to help track down "BUG at net/ipv4/tcp_output.c:438!"Herbert Xu
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>
2005-10-12[BRIDGE]: fix race on bridge del ifStephen Hemminger
This fixes the RCU race on bridge delete interface. Basically, the network device has to be detached from the bridge in the first step (pre-RCU), rather than later. At that point, no more bridge traffic will come in, and the other code will not think that network device is part of a bridge. This should also fix the XEN test problems. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[TWSK]: Grab the module refcount for timewait socketsArnaldo Carvalho de Melo
This is required to avoid unloading a module that has active timewait sockets, such as DCCP. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[DCCP]: Transition from PARTOPEN to OPEN when receiving DATA packetsArnaldo Carvalho de Melo
Noticed by Andrea Bittau, that provided a patch that was modified to not transition from RESPOND to OPEN when receiving DATA packets. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[CCID]: Check if ccid is NULL in the hc_[tr]x_exit functionsArnaldo Carvalho de Melo
For consistency with ccid_exit and to fix a bug when IP_DCCP_UNLOAD_HACK is enabled as the control sock is not associated to any CCID. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[NETFILTER] ctnetlink: add support to change protocol infoPablo Neira Ayuso
This patch add support to change the state of the private protocol information via conntrack_netlink. 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>
2005-10-10[NETFILTER] ctnetlink: allow userspace to change TCP statePablo Neira Ayuso
This patch adds the ability of changing the state a TCP connection. I know that this must be used with care but it's required to provide a complete conntrack creation via conntrack_netlink. So I'll document this aspect on the upcoming docs. 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>
2005-10-10[NETFILTER]: Use only 32bit counters for CONNTRACK_ACCTHarald Welte
Initially we used 64bit counters for conntrack-based accounting, since we had no event mechanism to tell userspace that our counters are about to overflow. With nfnetlink_conntrack, we now have such a event mechanism and thus can save 16bytes per connection. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[IPSEC] Fix block size/MTU bugs in ESPHerbert Xu
This patch fixes the following bugs in ESP: * Fix transport mode MTU overestimate. This means that the inner MTU is smaller than it needs be. Worse yet, given an input MTU which is a multiple of 4 it will always produce an estimate which is not a multiple of 4. For example, given a standard ESP/3DES/MD5 transform and an MTU of 1500, the resulting MTU for transport mode is 1462 when it should be 1464. The reason for this is because IP header lengths are always a multiple of 4 for IPv4 and 8 for IPv6. * Ensure that the block size is at least 4. This is required by RFC2406 and corresponds to what the esp_output function does. At the moment this only affects crypto_null as its block size is 1. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[IPSEC]: Use ALIGN macro in ESPHerbert Xu
This patch uses the macro ALIGN in all the applicable spots for ESP. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[NETFILTER] ctnetlink: add one nesting level for TCP statePablo Neira Ayuso
To keep consistency, the TCP private protocol information is nested attributes under CTA_PROTOINFO_TCP. This way the sequence of attributes to access the TCP state information looks like here below: CTA_PROTOINFO CTA_PROTOINFO_TCP CTA_PROTOINFO_TCP_STATE instead of: CTA_PROTOINFO CTA_PROTOINFO_TCP_STATE 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>
2005-10-10[NETFILTER] ctnetlink: ICMP ID is not mandatoryPablo Neira Ayuso
The ID is only required by ICMP type 8 (echo), so it's not mandatory for all sort of ICMP connections. This patch makes mandatory only the type and the code for ICMP netlink 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>
2005-10-10[NETFILTER] conntrack_netlink: Fix endian issue with status from userspaceHarald Welte
When we send "status" from userspace, we forget to convert the endianness. This patch adds the reqired conversion. Thanks to Pablo Neira for discovering this. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[NETFILTER] nfnetlink: use highest bit of nfa_type to indicate nested TLVHarald Welte
As Henrik Nordstrom pointed out, all our efforts with "split endian" (i.e. host byte order tags, net byte order values) are useless, unless a parser can determine whether an attribute is nested or not. This patch steals the highest bit of nfattr.nfa_type to indicate whether the data payload contains a nested nfattr (1) or not (0). This will break userspace compatibility, but luckily no kernel with nfnetlink was released so far. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[NETFILTER] ipt_ULOG: Mark ipt_ULOG as OBSOLETEHarald Welte
Similar to nfnetlink_queue and ip_queue, we mark ipt_ULOG as obsolete. This should have been part of the original nfnetlink_log merge, but I somehow missed it. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10[NETFILTER] PPTP helper: Add missing Kconfig dependencyHarald Welte
PPTP should not be selectable without conntrack enabled Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-08[PATCH] gfp flags annotations - part 1Al Viro
- 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>
2005-10-07[ATM]: [br2684] if we free the skb, we should return 0Jean-Denis Boyer
From: "Jean-Denis Boyer" <jdboyer@mediatrix.com> Signed-off-by: Chas Williams <chas@cmf.nrl.navy.mil> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-06[ATM]: add support for LECS addresses learned from networkEric Kinzie
From: Eric Kinzie <ekinzie@cmf.nrl.navy.mil> Signed-off-by: Chas Williams <chas@cmf.nrl.navy.mil> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-06[SCTP] Fix sctp_get{pl}addrs() API to work with 32-bit apps on 64-bit kernels.Ivan Skytte Jørgensen
The old socket options are marked with a _OLD suffix so that the existing 32-bit apps on 32-bit kernels do not break. Signed-off-by: Ivan Skytte Jørgensen <isj-sctp@i1.dk> Signed-off-by: Sridhar Samudrala <sri@us.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-05[AX.25]: Fix packet socket crashRalf Baechle
Since changeset 98a82febb6340466824c3a453738d4fbd05db81a AX.25 is passing received IP and ARP packets to the stack through netif_rx() but we don't set the skb->mac.raw to right value which may result in a crash with applications that use a packet socket. Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-05[IPSEC]: Document that policy direction is derived from the index.Herbert Xu
Here is a patch that adds a helper called xfrm_policy_id2dir to document the fact that the policy direction can be and is derived from the index. This is based on a patch by YOSHIFUJI Hideaki and 210313105@suda.edu.cn. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-05[IPV6]: Fix NS handing for proxy/anycast addressYOSHIFUJI Hideaki
Timer set up by pneigh_enqueue() ended up calling ndisc_rcv() via pndisc_redo(), which clears LOCALLY_ENQUEUED flag in NEIGH_CB(skb) and NS was queued again. Let's call ndisc_recv_ns() directly to avoid the loop. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-05[TCP]: BIC coding bug in Linux 2.6.13Stephen Hemminger
Missing parenthesis in causes BIC to be slow in increasing congestion window. Spotted by Injong Rhee. Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-05[MCAST] ipv6: Fix address size in grec_sizeYan Zheng
Signed-Off-By: Yan Zheng <yanzheng@21cn.com> Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Acked-by: David L Stevens <dlstevens@us.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[XFRM]: fix sparse gfp nocast warningsRandy Dunlap
Fix implicit nocast warnings in xfrm code: net/xfrm/xfrm_policy.c:232:47: warning: implicit cast to nocast type Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[RPC]: fix sparse gfp nocast warningsRandy Dunlap
Fix nocast sparse warnings: net/rxrpc/call.c:2013:25: warning: implicit cast to nocast type net/rxrpc/connection.c:538:46: warning: implicit cast to nocast type net/sunrpc/sched.c:730:36: warning: implicit cast to nocast type net/sunrpc/sched.c:734:56: warning: implicit cast to nocast type Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[AF_KEY]: fix sparse gfp nocast warningsRandy Dunlap
Fix implicit nocast warnings in net/key code: net/key/af_key.c:195:27: warning: implicit cast to nocast type net/key/af_key.c:1439:28: warning: implicit cast to nocast type Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[NETFILTER]: fix sparse gfp nocast warningsRandy Dunlap
Fix implicit nocast warnings in nfnetlink code: net/netfilter/nfnetlink.c:204:43: warning: implicit cast to nocast type Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[IPVS]: fix sparse gfp nocast warningsRandy Dunlap
From: Randy Dunlap <rdunlap@xenotime.net> Fix implicit nocast warnings in ip_vs code: net/ipv4/ipvs/ip_vs_app.c:631:54: warning: implicit cast to nocast type Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[DECNET]: fix sparse gfp nocast warningsRandy Dunlap
Fix implicit nocast warnings in decnet code: net/decnet/af_decnet.c:458:40: warning: implicit cast to nocast type net/decnet/dn_nsp_out.c:125:35: warning: implicit cast to nocast type net/decnet/dn_nsp_out.c:219:29: warning: implicit cast to nocast type Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[ATM]: fix sparse gfp nocast warningsRandy Dunlap
Fix implicit nocast warnings in atm code: net/atm/atm_misc.c:35:44: warning: implicit cast to nocast type drivers/atm/fore200e.c:183:33: warning: implicit cast to nocast type Also use kzalloc() instead of kmalloc(). Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[NETFILTER]: Fix Kconfig typoHorst H. von Brand
Signed-off-by: Horst H. von Brand <vonbrand@inf.utfsm.cl> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[IPV4]: fib_trie root-node expansionRobert Olsson
The patch below introduces special thresholds to keep root node in the trie large. This gives a flatter tree at the cost of a modest memory increase. Overall it seems to be gain and this was also proposed by one the authors of the paper in recent a seminar. Main table after loading 123 k routes. Aver depth: 3.30 Max depth: 9 Root-node size 12 bits Total size: 4044 kB With the patch: Aver depth: 2.78 Max depth: 8 Root-node size 15 bits Total size: 4150 kB An increase of 8-10% was seen in forwading performance for an rDoS attack. Signed-off-by: Robert Olsson <robert.olsson@its.uu.se> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[IPV6]: Fix infinite loop in udp_v6_get_port().YOSHIFUJI Hideaki
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-04[PATCH] ieee80211: fix gfp flags typeRandy Dunlap
Fix implicit nocast warnings in ieee80211 code, including __nocast: net/ieee80211/ieee80211_tx.c:215:9: warning: implicit cast to nocast type Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-10-03[PATCH] ieee80211: fix gfp flags typeRandy Dunlap
Fix implicit nocast warnings in ieee80211 code: net/ieee80211/ieee80211_tx.c:215:9: warning: implicit cast to nocast type Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
2005-10-03[IPV4]: Update icmp sysctl docs and disable broadcast ECHO/TIMESTAMP by defaultDavid S. Miller
It's not a good idea to be smurf'able by default. The few people who need this can turn it on. Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-03[IPV4]: Get rid of bogus __in_put_dev in pktgenHerbert Xu
This patch gets rid of a bogus __in_dev_put() in pktgen.c. This was spotted by Suzanne Wood. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-03[IPV4]: Replace __in_dev_get with __in_dev_get_rcu/rtnlHerbert Xu
The following patch renames __in_dev_get() to __in_dev_get_rtnl() and introduces __in_dev_get_rcu() to cover the second case. 1) RCU with refcnt should use in_dev_get(). 2) RCU without refcnt should use __in_dev_get_rcu(). 3) All others must hold RTNL and use __in_dev_get_rtnl(). There is one exception in net/ipv4/route.c which is in fact a pre-existing race condition. I've marked it as such so that we remember to fix it. This patch is based on suggestions and prior work by Suzanne Wood and Paul McKenney. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-03[IPV6]: Fix leak added by udp connect dst caching fix.David S. Miller
Based upon a patch from Mitsuru KANDA <mk@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-03[IPV6]: Fix ipv6 fragment ID selection at slow pathYan Zheng
Signed-Off-By: Yan Zheng <yanzheng@21cn.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-03[IPV4]: Fix "Proxy ARP seems broken"Herbert Xu
Meelis Roos <mroos@linux.ee> wrote: > RK> My firewall setup relies on proxyarp working. However, with 2.6.14-rc3, > RK> it appears to be completely broken. The firewall is 212.18.232.186, > > Same here with some kernel between 14-rc2 and 14-rc3 - no reposnse to > ARP on a proxyarp gateway. Sorry, no exact revison and no more debugging > yet since it'a a production gateway. The breakage is caused by the change to use the CB area for flagging whether a packet has been queued due to proxy_delay. This area gets cleared every time arp_rcv gets called. Unfortunately packets delayed due to proxy_delay also go through arp_rcv when they are reprocessed. In fact, I can't think of a reason why delayed proxy packets should go through netfilter again at all. So the easiest solution is to bypass that and go straight to arp_process. This is essentially what would've happened before netfilter support was added to ARP. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-03[NET]: Fix "sysctl_net.c:36: error: 'core_table' undeclared here"Russell King
During the build for ARM machine type "fortunet", this error occurred: CC net/sysctl_net.o net/sysctl_net.c:36: error: 'core_table' undeclared here (not in a function) It appears that the following configuration settings cause this error due to a missing include: CONFIG_SYSCTL=y CONFIG_NET=y # CONFIG_INET is not set core_table appears to be declared in net/sock.h. if CONFIG_INET were defined, net/sock.h would have been included via: sysctl_net.c -> net/ip.h -> linux/ip.h -> net/sock.h so include it directly. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-03[INET]: speedup inet (tcp/dccp) lookupsEric Dumazet
Arnaldo and I agreed it could be applied now, because I have other pending patches depending on this one (Thank you Arnaldo) (The other important patch moves skc_refcnt in a separate cache line, so that the SMP/NUMA performance doesnt suffer from cache line ping pongs) 1) First some performance data : -------------------------------- tcp_v4_rcv() wastes a *lot* of time in __inet_lookup_established() The most time critical code is : sk_for_each(sk, node, &head->chain) { if (INET_MATCH(sk, acookie, saddr, daddr, ports, dif)) goto hit; /* You sunk my battleship! */ } The sk_for_each() does use prefetch() hints but only the begining of "struct sock" is prefetched. As INET_MATCH first comparison uses inet_sk(__sk)->daddr, wich is far away from the begining of "struct sock", it has to bring into CPU cache cold cache line. Each iteration has to use at least 2 cache lines. This can be problematic if some chains are very long. 2) The goal ----------- The idea I had is to change things so that INET_MATCH() may return FALSE in 99% of cases only using the data already in the CPU cache, using one cache line per iteration. 3) Description of the patch --------------------------- Adds a new 'unsigned int skc_hash' field in 'struct sock_common', filling a 32 bits hole on 64 bits platform. struct sock_common { unsigned short skc_family; volatile unsigned char skc_state; unsigned char skc_reuse; int skc_bound_dev_if; struct hlist_node skc_node; struct hlist_node skc_bind_node; atomic_t skc_refcnt; + unsigned int skc_hash; struct proto *skc_prot; }; Store in this 32 bits field the full hash, not masked by (ehash_size - 1) Using this full hash as the first comparison done in INET_MATCH permits us immediatly skip the element without touching a second cache line in case of a miss. Suppress the sk_hashent/tw_hashent fields since skc_hash (aliased to sk_hash and tw_hash) already contains the slot number if we mask with (ehash_size - 1) File include/net/inet_hashtables.h 64 bits platforms : #define INET_MATCH(__sk, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ (((__sk)->sk_hash == (__hash)) ((*((__u64 *)&(inet_sk(__sk)->daddr)))== (__cookie)) && \ ((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports)) && \ (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 32bits platforms: #define TCP_IPV4_MATCH(__sk, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ (((__sk)->sk_hash == (__hash)) && \ (inet_sk(__sk)->daddr == (__saddr)) && \ (inet_sk(__sk)->rcv_saddr == (__daddr)) && \ (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) - Adds a prefetch(head->chain.first) in __inet_lookup_established()/__tcp_v4_check_established() and __inet6_lookup_established()/__tcp_v6_check_established() and __dccp_v4_check_established() to bring into cache the first element of the list, before the {read|write}_lock(&head->lock); Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-03[NET]: Fix packet timestamping.Herbert Xu
I've found the problem in general. It affects any 64-bit architecture. The problem occurs when you change the system time. Suppose that when you boot your system clock is forward by a day. This gets recorded down in skb_tv_base. You then wind the clock back by a day. From that point onwards the offset will be negative which essentially overflows the 32-bit variables they're stored in. In fact, why don't we just store the real time stamp in those 32-bit variables? After all, we're not going to overflow for quite a while yet. When we do overflow, we'll need a better solution of course. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-29[ATM]: [lec] reset retry counter when new arp issuedScott Talbert
From: Scott Talbert <scott.talbert@lmco.com> Signed-off-by: Chas Williams <chas@cmf.nrl.navy.mil> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-29[ATM]: [lec] attempt to support cisco failoverScott Talbert
From: Scott Talbert <scott.talbert@lmco.com> Signed-off-by: Chas Williams <chas@cmf.nrl.navy.mil> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-29[TCP]: Don't over-clamp window in tcp_clamp_window()Alexey Kuznetsov
From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Handle better the case where the sender sends full sized frames initially, then moves to a mode where it trickles out small amounts of data at a time. This known problem is even mentioned in the comments above tcp_grow_window() in tcp_input.c, specifically: ... * The scheme does not work when sender sends good segments opening * window and then starts to feed us spagetti. But it should work * in common situations. Otherwise, we have to rely on queue collapsing. ... When the sender gives full sized frames, the "struct sk_buff" overhead from each packet is small. So we'll advertize a larger window. If the sender moves to a mode where small segments are sent, this ratio becomes tilted to the other extreme and we start overrunning the socket buffer space. tcp_clamp_window() tries to address this, but it's clamping of tp->window_clamp is a wee bit too aggressive for this particular case. Fix confirmed by Ion Badulescu. Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-29[TCP]: Revert 6b251858d377196b8cea20e65cae60f584a42735David S. Miller
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>