linux/include/net/request_sock.h, branch v2.6.26

tcp: Revert 'process defer accept as established' changes.

2008-06-12T23:34:35Z

This reverts two changesets, ec3c0982a2dd1e671bad8e9d26c28dcba0039d87 ("[TCP]: TCP_DEFER_ACCEPT updates - process as established") and the follow-on bug fix 9ae27e0adbf471c7a6b80102e38e1d5a346b3b38 ("tcp: Fix slab corruption with ipv6 and tcp6fuzz"). This change causes several problems, first reported by Ingo Molnar as a distcc-over-loopback regression where connections were getting stuck. Ilpo Järvinen first spotted the locking problems. The new function added by this code, tcp_defer_accept_check(), only has the child socket locked, yet it is modifying state of the parent listening socket. Fixing that is non-trivial at best, because we can't simply just grab the parent listening socket lock at this point, because it would create an ABBA deadlock. The normal ordering is parent listening socket --> child socket, but this code path would require the reverse lock ordering. Next is a problem noticed by Vitaliy Gusev, he noted: ---------------------------------------- >--- a/net/ipv4/tcp_timer.c >+++ b/net/ipv4/tcp_timer.c >@@ -481,6 +481,11 @@ static void tcp_keepalive_timer (unsigned long data) > goto death; > } > >+ if (tp->defer_tcp_accept.request && sk->sk_state == TCP_ESTABLISHED) { >+ tcp_send_active_reset(sk, GFP_ATOMIC); >+ goto death; Here socket sk is not attached to listening socket's request queue. tcp_done() will not call inet_csk_destroy_sock() (and tcp_v4_destroy_sock() which should release this sk) as socket is not DEAD. Therefore socket sk will be lost for freeing. ---------------------------------------- Finally, Alexey Kuznetsov argues that there might not even be any real value or advantage to these new semantics even if we fix all of the bugs: ---------------------------------------- Hiding from accept() sockets with only out-of-order data only is the only thing which is impossible with old approach. Is this really so valuable? My opinion: no, this is nothing but a new loophole to consume memory without control. ---------------------------------------- So revert this thing for now. Signed-off-by: David S. Miller

[Syncookies]: Add support for TCP options via timestamps.

2008-04-10T10:12:40Z

Allow the use of SACK and window scaling when syncookies are used and the client supports tcp timestamps. Options are encoded into the timestamp sent in the syn-ack and restored from the timestamp echo when the ack is received. Based on earlier work by Glenn Griffin. This patch avoids increasing the size of structs by encoding TCP options into the least significant bits of the timestamp and by not using any 'timestamp offset'. The downside is that the timestamp sent in the packet after the synack will increase by several seconds. changes since v1: don't duplicate timestamp echo decoding function, put it into ipv4/syncookie.c and have ipv6/syncookies.c use it. Feedback from Glenn Griffin: fix line indented with spaces, kill redundant if () Reviewed-by: Hagen Paul Pfeifer Signed-off-by: Florian Westphal Signed-off-by: David S. Miller

[TCP]: TCP_DEFER_ACCEPT updates - process as established

2008-03-21T23:33:01Z

Change TCP_DEFER_ACCEPT implementation so that it transitions a connection to ESTABLISHED after handshake is complete instead of leaving it in SYN-RECV until some data arrvies. Place connection in accept queue when first data packet arrives from slow path. Benefits: - established connection is now reset if it never makes it to the accept queue - diagnostic state of established matches with the packet traces showing completed handshake - TCP_DEFER_ACCEPT timeouts are expressed in seconds and can now be enforced with reasonable accuracy instead of rounding up to next exponential back-off of syn-ack retry. Signed-off-by: Patrick McManus Signed-off-by: David S. Miller

[INET]: Remove struct dst_entry *dst from request_sock_ops.rtx_syn_ack.

2008-02-29T19:43:03Z

It looks like dst parameter is used in this API due to historical reasons. Actually, it is really used in the direct call to tcp_v4_send_synack only. So, create a wrapper for tcp_v4_send_synack and remove dst from rtx_syn_ack. Signed-off-by: Denis V. Lunev Signed-off-by: David S. Miller

[INET]: Fix potential kfree on vmalloc-ed area of request_sock_queue

2007-11-15T10:57:06Z

The request_sock_queue's listen_opt is either vmalloc-ed or kmalloc-ed depending on the number of table entries. Thus it is expected to be handled properly on free, which is done in the reqsk_queue_destroy(). However the error path in inet_csk_listen_start() calls the lite version of reqsk_queue_destroy, called __reqsk_queue_destroy, which calls the kfree unconditionally. Fix this and move the __reqsk_queue_destroy into a .c file as it looks too big to be inline. As David also noticed, this is an error recovery path only, so no locking is required and the lopt is known to be not NULL. reqsk_queue_yank_listen_sk is also now only used in net/core/request_sock.c so we should move it there too. Signed-off-by: Pavel Emelyanov Acked-by: Eric Dumazet Signed-off-by: David S. Miller

[PATCH] slab: remove kmem_cache_t

2006-12-07T16:39:25Z

Replace all uses of kmem_cache_t with struct kmem_cache. The patch was generated using the following script: #!/bin/sh # # Replace one string by another in all the kernel sources. # set -e for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do quilt add $file sed -e "1,\$s/$1/$2/g" $file >/tmp/$$ mv /tmp/$$ $file quilt refresh done The script was run like this sh replace kmem_cache_t "struct kmem_cache" Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] slab: remove SLAB_ATOMIC

2006-12-07T16:39:24Z

SLAB_ATOMIC is an alias of GFP_ATOMIC Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[TCP]: MD5 Signature Option (RFC2385) support.

2006-12-03T05:22:39Z

Based on implementation by Rick Payne. Signed-off-by: YOSHIFUJI Hideaki Signed-off-by: David S. Miller

[NET]: Size listen hash tables using backlog hint

2006-12-03T05:21:44Z

We currently allocate a fixed size (TCP_SYNQ_HSIZE=512) slots hash table for each LISTEN socket, regardless of various parameters (listen backlog for example) On x86_64, this means order-1 allocations (might fail), even for 'small' sockets, expecting few connections. On the contrary, a huge server wanting a backlog of 50000 is slowed down a bit because of this fixed limit. This patch makes the sizing of listen hash table a dynamic parameter, depending of : - net.core.somaxconn tunable (default is 128) - net.ipv4.tcp_max_syn_backlog tunable (default : 256, 1024 or 128) - backlog value given by user application (2nd parameter of listen()) For large allocations (bigger than PAGE_SIZE), we use vmalloc() instead of kmalloc(). We still limit memory allocation with the two existing tunables (somaxconn & tcp_max_syn_backlog). So for standard setups, this patch actually reduce RAM usage. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

SELinux: Return correct context for SO_PEERSEC

2006-12-03T05:21:33Z

Fix SO_PEERSEC for tcp sockets to return the security context of the peer (as represented by the SA from the peer) as opposed to the SA used by the local/source socket. Signed-off-by: Venkat Yekkirala Signed-off-by: James Morris