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path: root/net/ipv4/tcp_ipv4.c
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2008-07-25net: convert BUG_TRAP to generic WARN_ONIlpo Järvinen
Removes legacy reinvent-the-wheel type thing. The generic machinery integrates much better to automated debugging aids such as kerneloops.org (and others), and is unambiguous due to better naming. Non-intuively BUG_TRAP() is actually equal to WARN_ON() rather than BUG_ON() though some might actually be promoted to BUG_ON() but I left that to future. I could make at least one BUILD_BUG_ON conversion. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-19tcp: fix kernel panic with listening_get_nextDaniel Lezcano
# BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 IP: [<ffffffff821ed01e>] listening_get_next+0x50/0x1b3 PGD 11e4b9067 PUD 11d16c067 PMD 0 Oops: 0000 [1] SMP last sysfs file: /sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map CPU 3 Modules linked in: bridge ipv6 button battery ac loop dm_mod tg3 ext3 jbd edd fan thermal processor thermal_sys hwmon sg sata_svw libata dock serverworks sd_mod scsi_mod ide_disk ide_core [last unloaded: freq_table] Pid: 3368, comm: slpd Not tainted 2.6.26-rc2-mm1-lxc4 #1 RIP: 0010:[<ffffffff821ed01e>] [<ffffffff821ed01e>] listening_get_next+0x50/0x1b3 RSP: 0018:ffff81011e1fbe18 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8100be0ad3c0 RCX: ffff8100619f50c0 RDX: ffffffff82475be0 RSI: ffff81011d9ae6c0 RDI: ffff8100be0ad508 RBP: ffff81011f4f1240 R08: 00000000ffffffff R09: ffff8101185b6780 R10: 000000000000002d R11: ffffffff820fdbfa R12: ffff8100be0ad3c8 R13: ffff8100be0ad6a0 R14: ffff8100be0ad3c0 R15: ffffffff825b8ce0 FS: 00007f6a0ebd16d0(0000) GS:ffff81011f424540(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000038 CR3: 000000011dc20000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process slpd (pid: 3368, threadinfo ffff81011e1fa000, task ffff81011f4b8660) Stack: 00000000000002ee ffff81011f5a57c0 ffff81011f4f1240 ffff81011e1fbe90 0000000000001000 0000000000000000 00007fff16bf2590 ffffffff821ed9c8 ffff81011f5a57c0 ffff81011d9ae6c0 000000000000041a ffffffff820b0abd Call Trace: [<ffffffff821ed9c8>] ? tcp_seq_next+0x34/0x7e [<ffffffff820b0abd>] ? seq_read+0x1aa/0x29d [<ffffffff820d21b4>] ? proc_reg_read+0x73/0x8e [<ffffffff8209769c>] ? vfs_read+0xaa/0x152 [<ffffffff82097a7d>] ? sys_read+0x45/0x6e [<ffffffff8200bd2b>] ? system_call_after_swapgs+0x7b/0x80 Code: 31 a9 25 00 e9 b5 00 00 00 ff 45 20 83 7d 0c 01 75 79 4c 8b 75 10 48 8b 0e eb 1d 48 8b 51 20 0f b7 45 08 39 02 75 0e 48 8b 41 28 <4c> 39 78 38 0f 84 93 00 00 00 48 8b 09 48 85 c9 75 de 8b 55 1c RIP [<ffffffff821ed01e>] listening_get_next+0x50/0x1b3 RSP <ffff81011e1fbe18> CR2: 0000000000000038 This kernel panic appears with CONFIG_NET_NS=y. How to reproduce ? On the buggy host (host A) * ip addr add 1.2.3.4/24 dev eth0 On a remote host (host B) * ip addr add 1.2.3.5/24 dev eth0 * iptables -A INPUT -p tcp -s 1.2.3.4 -j DROP * ssh 1.2.3.4 On host A: * netstat -ta or cat /proc/net/tcp This bug happens when reading /proc/net/tcp[6] when there is a req_sock at the SYN_RECV state. When a SYN is received the minisock is created and the sk field is set to NULL. In the listening_get_next function, we try to look at the field req->sk->sk_net. When looking at how to fix this bug, I noticed that is useless to do the check for the minisock belonging to the namespace. A minisock belongs to a listen point and this one is per namespace, so when browsing the minisock they are always per namespace. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-19tcp: Fix MD5 signatures for non-linear skbsAdam Langley
Currently, the MD5 code assumes that the SKBs are linear and, in the case that they aren't, happily goes off and hashes off the end of the SKB and into random memory. Reported by Stephen Hemminger in [1]. Advice thanks to Stephen and Evgeniy Polyakov. Also includes a couple of missed route_caps from Stephen's patch in [2]. [1] http://marc.info/?l=linux-netdev&m=121445989106145&w=2 [2] http://marc.info/?l=linux-netdev&m=121459157816964&w=2 Signed-off-by: Adam Langley <agl@imperialviolet.org> Acked-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-16mib: add net to NET_INC_STATS_BHPavel Emelyanov
Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-16mib: add net to TCP_INC_STATS_BHPavel Emelyanov
Same as before - the sock is always there to get the net from, but there are also some places with the net already saved on the stack. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-16inet: prepare struct net for TCP MIB accountingPavel Emelyanov
This is the same as the first patch in the set, but preparing the net for TCP_XXX_STATS - save the struct net on the stack where required and possible. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-16mib: add net to IP_INC_STATS_BHPavel Emelyanov
Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-14mib: add struct net to ICMP_INC_STATS_BHPavel Emelyanov
Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-14inet: toss struct net initialization aroundPavel Emelyanov
Some places, that deal with ICMP statistics already have where to get a struct net from, but use it directly, without declaring a separate variable on the stack. Since I will need this net soon, I declare a struct net on the stack and use it in the existing places in a separate patch not to spoil the future ones. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-06-28Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/iwlwifi/iwl4965-base.c
2008-06-27tcp: /proc/net/tcp rto,ato values not scaled properly (v2)Stephen Hemminger
I found another case where we are sending information to userspace in the wrong HZ scale. This should have been fixed back in 2.5 :-( This means an ABI change but as it stands there is no way for an application like ss to get the right value. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-06-16Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/rt2x00/Kconfig drivers/net/wireless/rt2x00/rt2x00usb.c net/sctp/protocol.c
2008-06-16ipv4: Remove unused definitions in net/ipv4/tcp_ipv4.c.Rami Rosen
1) Remove ICMP_MIN_LENGTH, as it is unused. 2) Remove unneeded tcp_v4_send_check() declaration. Signed-off-by: Rami Rosen <ramirose@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-06-14net: change proto destroy method to return voidBrian Haley
Change struct proto destroy function pointer to return void. Noticed by Al Viro. Signed-off-by: Brian Haley <brian.haley@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-06-13Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/smc911x.c
2008-06-12tcp: Revert 'process defer accept as established' changes.David S. Miller
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 <davem@davemloft.net>
2008-06-11Merge branch 'net-next-2.6-misc-20080612a' of ↵David S. Miller
git://git.linux-ipv6.org/gitroot/yoshfuji/linux-2.6-next
2008-06-11net: remove CVS keywordsAdrian Bunk
This patch removes CVS keywords that weren't updated for a long time from comments. Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-06-12tcp md5sig: Let the caller pass appropriate key for ↵YOSHIFUJI Hideaki
tcp_v{4,6}_do_calc_md5_hash(). As we do for other socket/timewait-socket specific parameters, let the callers pass appropriate arguments to tcp_v{4,6}_do_calc_md5_hash(). Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
2008-06-12tcp md5sig: Share most of hash calcucaltion bits between IPv4 and IPv6.YOSHIFUJI Hideaki
We can share most part of the hash calculation code because the only difference between IPv4 and IPv6 is their pseudo headers. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
2008-06-12tcp md5sig: Remove redundant protocol argument.YOSHIFUJI Hideaki
Protocol is always TCP, so remove useless protocol argument. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
2008-06-12tcp md5sig: Share MD5 Signature option parser between IPv4 and IPv6.YOSHIFUJI Hideaki
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
2008-06-10inet{6}_request_sock: Init ->opt and ->pktopts in the constructorArnaldo Carvalho de Melo
Wei Yongjun noticed that we may call reqsk_free on request sock objects where the opt fields may not be initialized, fix it by introducing inet_reqsk_alloc where we initialize ->opt to NULL and set ->pktopts to NULL in inet6_reqsk_alloc. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-02ipv4: assign PDE->data before gluing PDE into /proc treeDenis V. Lunev
The check for PDE->data != NULL becomes useless after the replacement of proc_net_fops_create with proc_create_data. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-24[NET]: Fix heavy stack usage in seq_file output routines.Pavel Emelyanov
Plan C: we can follow the Al Viro's proposal about %n like in this patch. The same applies to udp, fib (the /proc/net/route file), rt_cache and sctp debug. This is minus ~150-200 bytes for each. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-14[IPV4]: Use NIPQUAD_FMT to format ipv4 addresses.YOSHIFUJI Hideaki
And use %u to format port. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-13[TCP]: Remove owner from tcp_seq_afinfo.Denis V. Lunev
Move it to tcp_seq_afinfo->seq_fops as should be. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-13[TCP]: Place file operations directly into tcp_seq_afinfo.Denis V. Lunev
No need to have separate never-used variable. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-13[TCP]: Cleanup /proc/tcp[6] creation/removal.Denis V. Lunev
Replace seq_open with seq_open_net and remove tcp_seq_release completely. seq_release_net will do this job just fine. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-13[TCP]: Move seq_ops from tcp_iter_state to tcp_seq_afinfo.Denis V. Lunev
No need to create seq_operations for each instance of 'netstat'. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-13[TCP]: No need to check afinfo != NULL in tcp_proc_(un)register.Denis V. Lunev
tcp_proc_register/tcp_proc_unregister are called with a static pointer only. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-13[TCP]: Replace struct net on tcp_iter_state with seq_net_private.Denis V. Lunev
Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-10[Syncookies]: Add support for TCP options via timestamps.Florian Westphal
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 <hagen@jauu.net> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-03[NETNS]: Use TCP control socket from a correct namespace.Denis V. Lunev
Signed-off-by: Denis V.Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-03[NETNS]: Create tcp control socket in the each namespace.Denis V. Lunev
Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-03[NETNS]: Inet control socket should not hold a namespace.Denis V. Lunev
This is a generic requirement, so make inet_ctl_sock_create namespace aware and create a inet_ctl_sock_destroy wrapper around sk_release_kernel. Signed-off-by: Denis V. Lunev <den@openvz.org> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-03[INET]: Let inet_ctl_sock_create return sock rather than socket.Denis V. Lunev
All upper protocol layers are already use sock internally. Signed-off-by: Denis V. Lunev <den@openvz.org> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-03[INET]: Rename inet_csk_ctl_sock_create to inet_ctl_sock_create.Denis V. Lunev
This call is nothing common with INET connection sockets code. It simply creates an unhashes kernel sockets for protocol messages. Move the new call into af_inet.c after the rename. Signed-off-by: Denis V. Lunev <den@openvz.org> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-03[TCP]: Replace socket with sock for reset sending.Denis V. Lunev
Replace tcp_socket with tcp_sock. This is more effective (less derefferences on fast paths). Additionally, the approach is unified to one used in ICMP. Signed-off-by: Denis V. Lunev <den@openvz.org> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-28[SOCK]: Drop inuse pcounter from struct proto (v2).Pavel Emelyanov
An uppercut - do not use the pcounter on struct proto. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-26[NET] NETNS: Omit namespace comparision without CONFIG_NET_NS.YOSHIFUJI Hideaki
Introduce an inline net_eq() to compare two namespaces. Without CONFIG_NET_NS, since no namespace other than &init_net exists, it is always 1. We do not need to convert 1) inline vs inline and 2) inline vs &init_net comparisons. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
2008-03-26[NET] NETNS: Omit sock->sk_net without CONFIG_NET_NS.YOSHIFUJI Hideaki
Introduce per-sock inlines: sock_net(), sock_net_set() and per-inet_timewait_sock inlines: twsk_net(), twsk_net_set(). Without CONFIG_NET_NS, no namespace other than &init_net exists. Let's explicitly define them to help compiler optimizations. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
2008-03-26[NET] NETNS: Omit net_device->nd_net without CONFIG_NET_NS.YOSHIFUJI Hideaki
Introduce per-net_device inlines: dev_net(), dev_net_set(). Without CONFIG_NET_NS, no namespace other than &init_net exists. Let's explicitly define them to help compiler optimizations. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
2008-03-24[NETNS][TCP]: Register /proc/net/tcp in a namespace.Pavel Emelyanov
After the commit f40c8174d3c21bf178283f3ef3aa8c7bf238fdec ([NETNS][IPV4] tcp - make proc handle the network namespaces) it is now possible to make this file present in newly created namespaces. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-22[SOCK]: Add udp_hash member to struct proto.Pavel Emelyanov
Inspired by the commit ab1e0a13 ([SOCK] proto: Add hashinfo member to struct proto) from Arnaldo, I made similar thing for UDP/-Lite IPv4 and -v6 protocols. The result is not that exciting, but it removes some levels of indirection in udpxxx_get_port and saves some space in code and text. The first step is to union existing hashinfo and new udp_hash on the struct proto and give a name to this union, since future initialization of tcpxxx_prot, dccp_vx_protinfo and udpxxx_protinfo will cause gcc warning about inability to initialize anonymous member this way. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-21[TCP]: TCP_DEFER_ACCEPT updates - process as establishedPatrick McManus
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 <mcmanus@ducksong.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-21[NET]: NULL pointer dereference and other nasty things in /proc/net/(tcp|udp)[6]Pavel Emelyanov
Commits f40c81 ([NETNS][IPV4] tcp - make proc handle the network namespaces) and a91275 ([NETNS][IPV6] udp - make proc handle the network namespace) both introduced bad checks on sockets and tw buckets to belong to proper net namespace. I.e. when checking for socket to belong to given net and family the do { sk = sk_next(sk); } while (sk && sk->sk_net != net && sk->sk_family != family); constructions were used. This is wrong, since as soon as the sk->sk_net fits the net the socket is immediately returned, even if it belongs to other family. As the result four /proc/net/(udp|tcp)[6] entries show wrong info. The udp6 entry even oopses when dereferencing inet6_sk(sk) pointer: static void udp6_sock_seq_show(struct seq_file *seq, struct sock *sp, int bucket) { ... struct ipv6_pinfo *np = inet6_sk(sp); ... dest = &np->daddr; /* will be NULL for AF_INET sockets */ ... seq_printf(... dest->s6_addr32[0], dest->s6_addr32[1], dest->s6_addr32[2], dest->s6_addr32[3], ... Fix it by converting && to ||. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-21[NETNS][IPV6] tcp6 - make proc per namespaceDaniel Lezcano
Make the proc for tcp6 to be per namespace. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-21[NETNS][IPV4] tcp - make proc handle the network namespacesDaniel Lezcano
This patch, like udp proc, makes the proc functions to take care of which namespace the socket belongs. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-05[IPV4]: Add 'rtable' field in struct sk_buff to alias 'dst' and avoid castsEric Dumazet
(Anonymous) unions can help us to avoid ugly casts. A common cast it the (struct rtable *)skb->dst one. Defining an union like : union { struct dst_entry *dst; struct rtable *rtable; }; permits to use skb->rtable in place. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>