In the IPv6 forwarding path we are only concerend about the outgoing
interface MTU, but also respect locked MTUs on routes. Tunnel provider
or IPSEC already have to recheck and if needed send PtB notifications
to the sending host in case the data does not fit into the packet with
added headers (we only know the final header sizes there, while also
using path MTU information).

The reason for this change is, that path MTU information can be injected
into the kernel via e.g. icmp_err protocol handler without verification
of local sockets. As such, this could cause the IPv6 forwarding path to
wrongfully emit Packet-too-Big errors and drop IPv6 packets.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>
Cc: John Heffner <johnwheffner@gmail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Sockets marked with IPV6_PMTUDISC_PROBE (or later IPV6_PMTUDISC_INTERFACE)
don't respect this setting when the outgoing interface supports UFO.

We had the same problem in IPv4, which was fixed in commit
daba287b ("ipv4: fix DO and PROBE pmtu
mode regarding local fragmentation with UFO/CORK").

Also IPV6_DONTFRAG mode did not care about already corked data, thus
it may generate a fragmented frame even if this socket option was
specified. It also did not care about the length of the ipv6 header and
possible options.

In the error path allow the user to receive the pmtu notifications via
both, rxpmtu method or error queue. The user may opted in for both,
so deliver the notification to both error handlers (the handlers check
if the error needs to be enqueued).

Also report back consistent pmtu values when sending on an already
cork-appended socket.
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPV6_PMTU_INTERFACE is the same as IPV6_PMTU_PROBE for ipv6. Add it
nontheless for symmetry with IPv4 sockets. Also drop incoming MTU
information if this mode is enabled.

The additional bit in ipv6_pinfo just eats in the padding behind the
bitfield. There are no changes to the layout of the struct at all.
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ip6_forward() runs from softirq context, we can use the SNMP macros
assuming this.

Use same indentation for all IP6_INC_STATS_BH() calls.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

FLOWI_FLAG_CAN_SLEEP was used to notify xfrm about the posibility
to sleep until the needed states are resolved. This code is gone,
so FLOWI_FLAG_CAN_SLEEP is not needed anymore.
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>

IPv6 stats are 64 bits and thus are protected with a seqlock. By not
disabling bottom-half we could deadlock here if we don't disable bh and
a softirq reentrantly updates the same mib.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If reassembled packet would fit into outdev MTU, it is not fragmented
according the original frag size and it is send as single big packet.

The second case is if skb is gso. In that case fragmentation does not happen
according to the original frag size.

This patch fixes these.
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While enabling lockdep on seqlocks, I ran across the warning below
caused by the ipv6 stats being updated in both irq and non-irq context.

This patch changes from IP6_INC_STATS_BH to IP6_INC_STATS (suggested
by Eric Dumazet) to resolve this problem.

[   11.120383] =================================
[   11.121024] [ INFO: inconsistent lock state ]
[   11.121663] 3.12.0-rc1+ #68 Not tainted
[   11.122229] ---------------------------------
[   11.122867] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[   11.123741] init/4483 [HC0[0]:SC1[3]:HE1:SE0] takes:
[   11.124505]  (&stats->syncp.seq#6){+.?...}, at: [<c1ab80c2>] ndisc_send_ns+0xe2/0x130
[   11.125736] {SOFTIRQ-ON-W} state was registered at:
[   11.126447]   [<c10e0eb7>] __lock_acquire+0x5c7/0x1af0
[   11.127222]   [<c10e2996>] lock_acquire+0x96/0xd0
[   11.127925]   [<c1a9a2c3>] write_seqcount_begin+0x33/0x40
[   11.128766]   [<c1a9aa03>] ip6_dst_lookup_tail+0x3a3/0x460
[   11.129582]   [<c1a9e0ce>] ip6_dst_lookup_flow+0x2e/0x80
[   11.130014]   [<c1ad18e0>] ip6_datagram_connect+0x150/0x4e0
[   11.130014]   [<c1a4d0b5>] inet_dgram_connect+0x25/0x70
[   11.130014]   [<c198dd61>] SYSC_connect+0xa1/0xc0
[   11.130014]   [<c198f571>] SyS_connect+0x11/0x20
[   11.130014]   [<c198fe6b>] SyS_socketcall+0x12b/0x300
[   11.130014]   [<c1bbf880>] syscall_call+0x7/0xb
[   11.130014] irq event stamp: 1184
[   11.130014] hardirqs last  enabled at (1184): [<c1086901>] local_bh_enable+0x71/0x110
[   11.130014] hardirqs last disabled at (1183): [<c10868cd>] local_bh_enable+0x3d/0x110
[   11.130014] softirqs last  enabled at (0): [<c108014d>] copy_process.part.42+0x45d/0x11a0
[   11.130014] softirqs last disabled at (1147): [<c1086e05>] irq_exit+0xa5/0xb0
[   11.130014]
[   11.130014] other info that might help us debug this:
[   11.130014]  Possible unsafe locking scenario:
[   11.130014]
[   11.130014]        CPU0
[   11.130014]        ----
[   11.130014]   lock(&stats->syncp.seq#6);
[   11.130014]   <Interrupt>
[   11.130014]     lock(&stats->syncp.seq#6);
[   11.130014]
[   11.130014]  *** DEADLOCK ***
[   11.130014]
[   11.130014] 3 locks held by init/4483:
[   11.130014]  #0:  (rcu_read_lock){.+.+..}, at: [<c109363c>] SyS_setpriority+0x4c/0x620
[   11.130014]  #1:  (((&ifa->dad_timer))){+.-...}, at: [<c108c1c0>] call_timer_fn+0x0/0xf0
[   11.130014]  #2:  (rcu_read_lock){.+.+..}, at: [<c1ab6494>] ndisc_send_skb+0x54/0x5d0
[   11.130014]
[   11.130014] stack backtrace:
[   11.130014] CPU: 0 PID: 4483 Comm: init Not tainted 3.12.0-rc1+ #68
[   11.130014] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   11.130014]  00000000 00000000 c55e5c10 c1bb0e71 c57128b0 c55e5c4c c1badf79 c1ec1123
[   11.130014]  c1ec1484 00001183 00000000 00000000 00000001 00000003 00000001 00000000
[   11.130014]  c1ec1484 00000004 c5712dcc 00000000 c55e5c84 c10de492 00000004 c10755f2
[   11.130014] Call Trace:
[   11.130014]  [<c1bb0e71>] dump_stack+0x4b/0x66
[   11.130014]  [<c1badf79>] print_usage_bug+0x1d3/0x1dd
[   11.130014]  [<c10de492>] mark_lock+0x282/0x2f0
[   11.130014]  [<c10755f2>] ? kvm_clock_read+0x22/0x30
[   11.130014]  [<c10dd8b0>] ? check_usage_backwards+0x150/0x150
[   11.130014]  [<c10e0e74>] __lock_acquire+0x584/0x1af0
[   11.130014]  [<c10b1baf>] ? sched_clock_cpu+0xef/0x190
[   11.130014]  [<c10de58c>] ? mark_held_locks+0x8c/0xf0
[   11.130014]  [<c10e2996>] lock_acquire+0x96/0xd0
[   11.130014]  [<c1ab80c2>] ? ndisc_send_ns+0xe2/0x130
[   11.130014]  [<c1ab66d3>] ndisc_send_skb+0x293/0x5d0
[   11.130014]  [<c1ab80c2>] ? ndisc_send_ns+0xe2/0x130
[   11.130014]  [<c1ab80c2>] ndisc_send_ns+0xe2/0x130
[   11.130014]  [<c108cc32>] ? mod_timer+0xf2/0x160
[   11.130014]  [<c1aa706e>] ? addrconf_dad_timer+0xce/0x150
[   11.130014]  [<c1aa70aa>] addrconf_dad_timer+0x10a/0x150
[   11.130014]  [<c1aa6fa0>] ? addrconf_dad_completed+0x1c0/0x1c0
[   11.130014]  [<c108c233>] call_timer_fn+0x73/0xf0
[   11.130014]  [<c108c1c0>] ? __internal_add_timer+0xb0/0xb0
[   11.130014]  [<c1aa6fa0>] ? addrconf_dad_completed+0x1c0/0x1c0
[   11.130014]  [<c108c5b1>] run_timer_softirq+0x141/0x1e0
[   11.130014]  [<c1086b20>] ? __do_softirq+0x70/0x1b0
[   11.130014]  [<c1086b70>] __do_softirq+0xc0/0x1b0
[   11.130014]  [<c1086e05>] irq_exit+0xa5/0xb0
[   11.130014]  [<c106cfd5>] smp_apic_timer_interrupt+0x35/0x50
[   11.130014]  [<c1bbfbca>] apic_timer_interrupt+0x32/0x38
[   11.130014]  [<c10936ed>] ? SyS_setpriority+0xfd/0x620
[   11.130014]  [<c10e26c9>] ? lock_release+0x9/0x240
[   11.130014]  [<c10936d7>] ? SyS_setpriority+0xe7/0x620
[   11.130014]  [<c1bbee6d>] ? _raw_read_unlock+0x1d/0x30
[   11.130014]  [<c1093701>] SyS_setpriority+0x111/0x620
[   11.130014]  [<c109363c>] ? SyS_setpriority+0x4c/0x620
[   11.130014]  [<c1bbf880>] syscall_call+0x7/0xb
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: James Morris <jmorris@namei.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/1381186321-4906-5-git-send-email-john.stultz@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Make sure rt6i_gateway contains nexthop information in
all routes returned from lookup or when routes are directly
attached to skb for generated ICMP packets.

The effect of this patch should be a faster version of
rt6_nexthop() and the consideration of local addresses as
nexthop.
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now, if user application does:
sendto len<mtu flag MSG_MORE
sendto len>mtu flag 0
The skb is not treated as fragmented one because it is not initialized
that way. So move the initialization to fix this.

introduced by:
commit e89e9cf5 "[IPv4/IPv6]: UFO Scatter-gather approach"
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the following scenario the socket is corked:
If the first UDP packet is larger then the mtu we try to append it to the
write queue via ip6_ufo_append_data. A following packet, which is smaller
than the mtu would be appended to the already queued up gso-skb via
plain ip6_append_data. This causes random memory corruptions.

In ip6_ufo_append_data we also have to be careful to not queue up the
same skb multiple times. So setup the gso frame only when no first skb
is available.

This also fixes a shortcoming where we add the current packet's length to
cork->length but return early because of a packet > mtu with dontfrag set
(instead of sutracting it again).

Found with trinity.

Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It will be used the vxlan kernel module.
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently we don't initialize skb->protocol when transmitting data via
tcp, raw(with and without inclhdr) or udp+ufo or appending data directly
to the socket transmit queue (via ip6_append_data). This needs to be
done so that we can get the correct mtu in the xfrm layer.

Setting of skb->protocol happens only in functions where we also have
a transmitting socket and a new skb, so we don't overwrite old values.

Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>

If the socket had an IPV6_MTU value set, ip6_append_data_mtu lost track
of this when appending the second frame on a corked socket. This results
in the following splat:

[37598.993962] ------------[ cut here ]------------
[37598.994008] kernel BUG at net/core/skbuff.c:2064!
[37598.994008] invalid opcode: 0000 [#1] SMP
[37598.994008] Modules linked in: tcp_lp uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core videodev media vfat fat usb_storage fuse ebtable_nat xt_CHECKSUM bridge stp llc ipt_MASQUERADE nf_conntrack_netbios_ns nf_conntrack_broadcast ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat
+nf_nat_ipv4 nf_nat iptable_mangle nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables be2iscsi iscsi_boot_sysfs bnx2i cnic uio cxgb4i cxgb4 cxgb3i cxgb3 mdio libcxgbi ib_iser rdma_cm ib_addr iw_cm ib_cm ib_sa ib_mad ib_core iscsi_tcp libiscsi_tcp libiscsi
+scsi_transport_iscsi rfcomm bnep iTCO_wdt iTCO_vendor_support snd_hda_codec_conexant arc4 iwldvm mac80211 snd_hda_intel acpi_cpufreq mperf coretemp snd_hda_codec microcode cdc_wdm cdc_acm
[37598.994008]  snd_hwdep cdc_ether snd_seq snd_seq_device usbnet mii joydev btusb snd_pcm bluetooth i2c_i801 e1000e lpc_ich mfd_core ptp iwlwifi pps_core snd_page_alloc mei cfg80211 snd_timer thinkpad_acpi snd tpm_tis soundcore rfkill tpm tpm_bios vhost_net tun macvtap macvlan kvm_intel kvm uinput binfmt_misc
+dm_crypt i915 i2c_algo_bit drm_kms_helper drm i2c_core wmi video
[37598.994008] CPU 0
[37598.994008] Pid: 27320, comm: t2 Not tainted 3.9.6-200.fc18.x86_64 #1 LENOVO 27744PG/27744PG
[37598.994008] RIP: 0010:[<ffffffff815443a5>]  [<ffffffff815443a5>] skb_copy_and_csum_bits+0x325/0x330
[37598.994008] RSP: 0018:ffff88003670da18  EFLAGS: 00010202
[37598.994008] RAX: ffff88018105c018 RBX: 0000000000000004 RCX: 00000000000006c0
[37598.994008] RDX: ffff88018105a6c0 RSI: ffff88018105a000 RDI: ffff8801e1b0aa00
[37598.994008] RBP: ffff88003670da78 R08: 0000000000000000 R09: ffff88018105c040
[37598.994008] R10: ffff8801e1b0aa00 R11: 0000000000000000 R12: 000000000000fff8
[37598.994008] R13: 00000000000004fc R14: 00000000ffff0504 R15: 0000000000000000
[37598.994008] FS:  00007f28eea59740(0000) GS:ffff88023bc00000(0000) knlGS:0000000000000000
[37598.994008] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[37598.994008] CR2: 0000003d935789e0 CR3: 00000000365cb000 CR4: 00000000000407f0
[37598.994008] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[37598.994008] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[37598.994008] Process t2 (pid: 27320, threadinfo ffff88003670c000, task ffff88022c162ee0)
[37598.994008] Stack:
[37598.994008]  ffff88022e098a00 ffff88020f973fc0 0000000000000008 00000000000004c8
[37598.994008]  ffff88020f973fc0 00000000000004c4 ffff88003670da78 ffff8801e1b0a200
[37598.994008]  0000000000000018 00000000000004c8 ffff88020f973fc0 00000000000004c4
[37598.994008] Call Trace:
[37598.994008]  [<ffffffff815fc21f>] ip6_append_data+0xccf/0xfe0
[37598.994008]  [<ffffffff8158d9f0>] ? ip_copy_metadata+0x1a0/0x1a0
[37598.994008]  [<ffffffff81661f66>] ? _raw_spin_lock_bh+0x16/0x40
[37598.994008]  [<ffffffff8161548d>] udpv6_sendmsg+0x1ed/0xc10
[37598.994008]  [<ffffffff812a2845>] ? sock_has_perm+0x75/0x90
[37598.994008]  [<ffffffff815c3693>] inet_sendmsg+0x63/0xb0
[37598.994008]  [<ffffffff812a2973>] ? selinux_socket_sendmsg+0x23/0x30
[37598.994008]  [<ffffffff8153a450>] sock_sendmsg+0xb0/0xe0
[37598.994008]  [<ffffffff810135d1>] ? __switch_to+0x181/0x4a0
[37598.994008]  [<ffffffff8153d97d>] sys_sendto+0x12d/0x180
[37598.994008]  [<ffffffff810dfb64>] ? __audit_syscall_entry+0x94/0xf0
[37598.994008]  [<ffffffff81020ed1>] ? syscall_trace_enter+0x231/0x240
[37598.994008]  [<ffffffff8166a7e7>] tracesys+0xdd/0xe2
[37598.994008] Code: fe 07 00 00 48 c7 c7 04 28 a6 81 89 45 a0 4c 89 4d b8 44 89 5d a8 e8 1b ac b1 ff 44 8b 5d a8 4c 8b 4d b8 8b 45 a0 e9 cf fe ff ff <0f> 0b 66 0f 1f 84 00 00 00 00 00 66 66 66 66 90 55 48 89 e5 48
[37598.994008] RIP  [<ffffffff815443a5>] skb_copy_and_csum_bits+0x325/0x330
[37598.994008]  RSP <ffff88003670da18>
[37599.007323] ---[ end trace d69f6a17f8ac8eee ]---

While there, also check if path mtu discovery is activated for this
socket. The logic was adapted from ip6_append_data when first writing
on the corked socket.

This bug was introduced with commit
0c183379 ("ipv6: fix incorrect ipsec
fragment").

v2:
a) Replace IPV6_PMTU_DISC_DO with IPV6_PMTUDISC_PROBE.
b) Don't pass ipv6_pinfo to ip6_append_data_mtu (suggestion by Gao
   feng, thanks!).
c) Change mtu to unsigned int, else we get a warning about
   non-matching types because of the min()-macro type-check.
Acked-by: NGao feng <gaofeng@cn.fujitsu.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It's possible to use AF_INET6 sockets and to connect to an IPv4
destination. After this, socket dst cache is a pointer to a rtable,
not rt6_info.

ip6_sk_dst_check() should check the socket dst cache is IPv6, or else
various corruptions/crashes can happen.

Dave Jones can reproduce immediate crash with
trinity -q -l off -n -c sendmsg -c connect

With help from Hannes Frederic Sowa
Reported-by: NDave Jones <davej@redhat.com>
Reported-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Router Alert option is marked in skb.
Previously, IP6CB(skb)->ra was set to positive value for such packets.
Since commit dd3332bf ("ipv6: Store Router Alert option in IP6CB
directly."), IP6SKB_ROUTERALERT is set in IP6CB(skb)->flags, and
the value of Router Alert option (in network byte order) is set
to IP6CB(skb)->ra for such packets.

Multicast forwarding path uses that flag and value, but unicast
forwarding path does not use the flag and misuses IP6CB(skb)->ra
value.
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 0178b695 ("ipv6: Copy cork options in ip6_append_data")
added some code duplication and bad error recovery, leading to potential
crash in ip6_cork_release() as kfree() could be called with garbage.

use kzalloc() to make sure this wont happen.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Neal Cardwell <ncardwell@google.com>

Currently, sock_tx_timestamp() always returns 0. The comment that
describes the sock_tx_timestamp() function wrongly says that it
returns an error when an invalid argument is passed (from commit
20d49473, ``net: socket infrastructure for SO_TIMESTAMPING'').
Make the function void, so that we can also remove all the unneeded
if conditions that check for such a _non-existant_ error case in the
output path.
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reported-by: NErik Hugne <erik.hugne@ericsson.com>
Cc: Erik Hugne <erik.hugne@ericsson.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Calling icmpv6_send() on a local message size error leads to an
incorrect update of the path mtu in the case when IPsec is used.
So use ipv6_local_error() instead to notify the socket about the
error.
Reported-by: NJiri Bohac <jbohac@suse.cz>
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is declared in:
include/net/ip6_route.h:187:int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));

and net/ip6_route.h is already included.

Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- move ip6_nd_hdr() to its users' source files.
  In net/ipv6/mcast.c, it will be called ip6_mc_hdr().
- make return type to void since this function never fails.
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If neigh is not found, create new one.
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 299b0767 (ipv6: Fix IPsec slowpath fragmentation problem)
has introduced a error in the header length calculation that
provokes corrupted packets when non-fragmentable extensions
headers (Destination Option or Routing Header Type 2) are used.

rt->rt6i_nfheader_len is the length of the non-fragmentable
extension header, and it should be substracted to
rt->dst.header_len, and not to exthdrlen, as it was done before
commit 299b0767.

This patch reverts to the original and correct behavior. It has
been successfully tested with and without IPsec on packets
that include non-fragmentable extensions headers.
Signed-off-by: NRomain Kuntz <r.kuntz@ipflavors.com>
Acked-by: NSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is not only for readability but also for optimization.
What we do here is to build the 32bit word at the beginning of the ipv6
header (the "ip6_flow" virtual member of struct ip6_hdr in RFC3542) and
we do not need to read the tclass portion of the target buffer.
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

UDP offload needs some additional functions to be in the static kernel
for it work correclty.  Move those functions into the core.
Signed-off-by: NVlad Yasevich <vyasevic@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As suggested by Eric, we could introduce a helper function
for ipv6 too, to avoid checking if rt is NULL before
dst_release().

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

#if defined(CONFIG_FOO) || defined(CONFIG_FOO_MODULE)

can be replaced by

#if IS_ENABLED(CONFIG_FOO)

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We currently use a per socket order-0 page cache for tcp_sendmsg()
operations.

This page is used to build fragments for skbs.

Its done to increase probability of coalescing small write() into
single segments in skbs still in write queue (not yet sent)

But it wastes a lot of memory for applications handling many mostly
idle sockets, since each socket holds one page in sk->sk_sndmsg_page

Its also quite inefficient to build TSO 64KB packets, because we need
about 16 pages per skb on arches where PAGE_SIZE = 4096, so we hit
page allocator more than wanted.

This patch adds a per task frag allocator and uses bigger pages,
if available. An automatic fallback is done in case of memory pressure.

(up to 32768 bytes per frag, thats order-3 pages on x86)

This increases TCP stream performance by 20% on loopback device,
but also benefits on other network devices, since 8x less frags are
mapped on transmit and unmapped on tx completion. Alexander Duyck
mentioned a probable performance win on systems with IOMMU enabled.

Its possible some SG enabled hardware cant cope with bigger fragments,
but their ndo_start_xmit() should already handle this, splitting a
fragment in sub fragments, since some arches have PAGE_SIZE=65536

Successfully tested on various ethernet devices.
(ixgbe, igb, bnx2x, tg3, mellanox mlx4)
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Vijay Subramanian <subramanian.vijay@gmail.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: NVijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After this commit:
	commit 97cac082
	Author: David S. Miller <davem@davemloft.net>
	Date:   Mon Jul 2 22:43:47 2012 -0700

	    ipv6: Store route neighbour in rt6_info struct.

we no longer use RCU to protect route neighbour.

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The IPv6 conntrack fragmentation currently has a couple of shortcomings.
Fragmentes are collected in PREROUTING/OUTPUT, are defragmented, the
defragmented packet is then passed to conntrack, the resulting conntrack
information is attached to each original fragment and the fragments then
continue their way through the stack.

Helper invocation occurs in the POSTROUTING hook, at which point only
the original fragments are available. The result of this is that
fragmented packets are never passed to helpers.

This patch improves the situation in the following way:

- If a reassembled packet belongs to a connection that has a helper
  assigned, the reassembled packet is passed through the stack instead
  of the original fragments.

- During defragmentation, the largest received fragment size is stored.
  On output, the packet is refragmented if required. If the largest
  received fragment size exceeds the outgoing MTU, a "packet too big"
  message is generated, thus behaving as if the original fragments
  were passed through the stack from an outside point of view.

- The ipv6_helper() hook function can't receive fragments anymore for
  connections using a helper, so it is switched to use ipv6_skip_exthdr()
  instead of the netfilter specific nf_ct_ipv6_skip_exthdr() and the
  reassembled packets are passed to connection tracking helpers.

The result of this is that we can properly track fragmented packets, but
still generate ICMPv6 Packet too big messages if we would have before.

This patch is also required as a precondition for IPv6 NAT, where NAT
helpers might enlarge packets up to a point that they require
fragmentation. In that case we can't generate Packet too big messages
since the proper MTU can't be calculated in all cases (f.i. when
changing textual representation of a variable amount of addresses),
so the packet is transparently fragmented iff the original packet or
fragments would have fit the outgoing MTU.

IPVS parts by Jesper Dangaard Brouer <brouer@redhat.com>.
Signed-off-by: NPatrick McHardy <kaber@trash.net>

Only use it in the absolutely required cases:

1) COW'ing metrics

2) ipv4 PMTU

3) ipv4 redirects
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix a bug in ip6_dst_lookup_tail(), where typeof(dst) is
"struct dst_entry **", not "struct dst_entry *"
Reported-by: NFengguang Wu <wfg@linux.intel.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This makes for a simplified conversion away from dst_get_neighbour*().

All code outside of ipv6 will use neigh lookups via dst_neigh_lookup*().
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a dst_confirm() happens, mark the confirmation as pending in the
dst.  Then on the next packet out, when we have the neigh in-hand, do
the update.

This removes the dependency in dst_confirm() of dst's having an
attached neigh.

While we're here, remove the explicit 'dst' NULL check, all except 2
or 3 call sites ensure it's not NULL.  So just fix those cases up.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add dev_loopback_xmit() in order to deduplicate functions
ip_dev_loopback_xmit() (in net/ipv4/ip_output.c) and
ip6_dev_loopback_xmit() (in net/ipv6/ip6_output.c).

I was about to reinvent the wheel when I noticed that
ip_dev_loopback_xmit() and ip6_dev_loopback_xmit() do exactly what I
need and are not IP-only functions, but they were not available to reuse
elsewhere.

ip6_dev_loopback_xmit() does not have line "skb_dst_force(skb);", but I
understand that this is harmless, and should be in dev_loopback_xmit().
Signed-off-by: NMichel Machado <michel@digirati.com.br>
CC: "David S. Miller" <davem@davemloft.net>
CC: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
CC: James Morris <jmorris@namei.org>
CC: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
CC: Patrick McHardy <kaber@trash.net>
CC: Eric Dumazet <edumazet@google.com>
CC: Jiri Pirko <jpirko@redhat.com>
CC: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
CC: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There's a lot of places that open-code rt{,6}_get_peer() only because
they want to set 'create' to one.  So add an rt{,6}_get_peer_create()
for their sake.

There were also a few spots open-coding plain rt{,6}_get_peer() and
those are transformed here as well.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RFC 4293 defines ipIfStatsOutOctets (similar definition for
ipSystemStatsOutOctets):

   The total number of octets in IP datagrams delivered to the lower
   layers for transmission.  Octets from datagrams counted in
   ipIfStatsOutTransmits MUST be counted here.

And ipIfStatsOutTransmits:

   The total number of IP datagrams that this entity supplied to the
   lower layers for transmission.  This includes datagrams generated
   locally and those forwarded by this entity.

Therefore, IPSTATS_MIB_OUTOCTETS must be incremented when incrementing
IPSTATS_MIB_OUTFORWDATAGRAMS.

IP_UPD_PO_STATS is not used since ipIfStatsOutRequests must not
include forwarded datagrams:

   The total number of IP datagrams that local IP user-protocols
   (including ICMP) supplied to IP in requests for transmission.  Note
   that this counter does not include any datagrams counted in
   ipIfStatsOutForwDatagrams.
Signed-off-by: NVincent Bernat <bernat@luffy.cx>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit ad0081e4
"ipv6: Fragment locally generated tunnel-mode IPSec6 packets as needed"
the fragment of packets is incorrect.
because tunnel mode needs IPsec headers and trailer for all fragments,
while on transport mode it is sufficient to add the headers to the
first fragment and the trailer to the last.

so modify mtu and maxfraglen base on ipsec mode and if fragment is first
or last.

with my test,it work well(every fragment's size is the mtu)
and does not trigger slow fragment path.

Changes from v1:
	though optimization, mtu_prev and maxfraglen_prev can be delete.
	replace xfrm mode codes with dst_entry's new frag DST_XFRM_TUNNEL.
	add fuction ip6_append_data_mtu to make codes clearer.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>