Currently the truncated bit is set only when the mirrored packet
is larger than mtu.  For certain cases, the packet might already
been truncated before sending to the erspan tunnel.  In this case,
the patch detect whether the IP header's total length is larger
than the actual skb->len.  If true, this indicated that the
mirrored packet is truncated and set the erspan truncate bit.

I tested the patch using bpf_skb_change_tail helper function to
shrink the packet size and send to erspan tunnel.
Reported-by: NXiaoyan Jin <xiaoyanj@vmware.com>
Signed-off-by: NWilliam Tu <u9012063@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When adding tcp mmap() implementation, I forgot that socket lock
had to be taken before current->mm->mmap_sem. syzbot eventually caught
the bug.

Since we can not lock the socket in tcp mmap() handler we have to
split the operation in two phases.

1) mmap() on a tcp socket simply reserves VMA space, and nothing else.
  This operation does not involve any TCP locking.

2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements
 the transfert of pages from skbs to one VMA.
  This operation only uses down_read(&current->mm->mmap_sem) after
  holding TCP lock, thus solving the lockdep issue.

This new implementation was suggested by Andy Lutomirski with great details.

Benefits are :

- Better scalability, in case multiple threads reuse VMAS
   (without mmap()/munmap() calls) since mmap_sem wont be write locked.

- Better error recovery.
   The previous mmap() model had to provide the expected size of the
   mapping. If for some reason one part could not be mapped (partial MSS),
   the whole operation had to be aborted.
   With the tcp_zerocopy_receive struct, kernel can report how
   many bytes were successfuly mapped, and how many bytes should
   be read to skip the problematic sequence.

- No more memory allocation to hold an array of page pointers.
  16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/

- skbs are freed while mmap_sem has been released

Following patch makes the change in tcp_mmap tool to demonstrate
one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...)

Note that memcg might require additional changes.

Fixes: 93ab6cc6 ("tcp: implement mmap() for zero copy receive")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Suggested-by: NAndy Lutomirski <luto@kernel.org>
Cc: linux-mm@kvack.org
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allow specifying segment size in the send call.

The new control message performs the same function as socket option
UDP_SEGMENT while avoiding the extra system call.

[ Export udp_cmsg_send for ipv6. -DaveM ]
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When sending large datagrams that are later segmented, store data in
page frags to avoid copying from linear in skb_segment.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Support generic segmentation offload for udp datagrams. Callers can
concatenate and send at once the payload of multiple datagrams with
the same destination.

To set segment size, the caller sets socket option UDP_SEGMENT to the
length of each discrete payload. This value must be smaller than or
equal to the relevant MTU.

A follow-up patch adds cmsg UDP_SEGMENT to specify segment size on a
per send call basis.

Total byte length may then exceed MTU. If not an exact multiple of
segment size, the last segment will be shorter.

The implementation adds a gso_size field to the udp socket, ip(v6)
cmsg cookie and inet_cork structure to be able to set the value at
setsockopt or cmsg time and to work with both lockless and corked
paths.

Initial benchmark numbers show UDP GSO about as expensive as TCP GSO.

    tcp tso
     3197 MB/s 54232 msg/s 54232 calls/s
         6,457,754,262      cycles

    tcp gso
     1765 MB/s 29939 msg/s 29939 calls/s
        11,203,021,806      cycles

    tcp without tso/gso *
      739 MB/s 12548 msg/s 12548 calls/s
        11,205,483,630      cycles

    udp
      876 MB/s 14873 msg/s 624666 calls/s
        11,205,777,429      cycles

    udp gso
     2139 MB/s 36282 msg/s 36282 calls/s
        11,204,374,561      cycles

   [*] after reverting commit 0a6b2a1d
       ("tcp: switch to GSO being always on")

Measured total system cycles ('-a') for one core while pinning both
the network receive path and benchmark process to that core:

  perf stat -a -C 12 -e cycles \
    ./udpgso_bench_tx -C 12 -4 -D "$DST" -l 4

Note the reduction in calls/s with GSO. Bytes per syscall drops
increases from 1470 to 61818.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement generic segmentation offload support for udp datagrams. A
follow-up patch adds support to the protocol stack to generate such
packets.

UDP GSO is not UFO. UFO fragments a single large datagram. GSO splits
a large payload into a number of discrete UDP datagrams.

The implementation adds a GSO type SKB_UDP_GSO_L4 to differentiate it
from UFO (SKB_UDP_GSO).

IPPROTO_UDPLITE is excluded, as that protocol has no gso handler
registered.

[ Export __udp_gso_segment for ipv6. -DaveM ]
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

UDP segmentation offload needs access to inet_cork in the udp layer.
Pass the struct to ip(6)_make_skb instead of allocating it on the
stack in that function itself.

This patch is a noop otherwise.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The addrconf_ifdown() evaluates keep_addr_on_down state twice. There
is no need to do it.

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: NIvan Vecera <cera@cera.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ECMP (equal-cost multipath) hashes are typically computed on the packets'
5-tuple(src IP, dst IP, src port, dst port, L4 proto).

For encapsulated packets, the L4 data is not readily available and ECMP
hashing will often revert to (src IP, dst IP). This will lead to traffic
polarization on a single ECMP path, causing congestion and waste of network
capacity.

In IPv6, the 20-bit flow label field is also used as part of the ECMP hash.
In the lack of L4 data, the hashing will be on (src IP, dst IP, flow
label). Having a non-zero flow label is thus important for proper traffic
load balancing when L4 data is unavailable (i.e., when packets are
encapsulated).

Currently, the seg6_do_srh_encap() function extracts the original packet's
flow label and set it as the outer IPv6 flow label. There are two issues
with this behaviour:

a) There is no guarantee that the inner flow label is set by the source.
b) If the original packet is not IPv6, the flow label will be set to
zero (e.g., IPv4 or L2 encap).

This patch adds a function, named seg6_make_flowlabel(), that computes a
flow label from a given skb. It supports IPv6, IPv4 and L2 payloads, and
leverages the per namespace 'seg6_flowlabel" sysctl value.

The currently support behaviours are as follows:
-1 set flowlabel to zero.
0 copy flowlabel from Inner paceket in case of Inner IPv6
(Set flowlabel to 0 in case IPv4/L2)
1 Compute the flowlabel using seg6_make_flowlabel()

This patch has been tested for IPv6, IPv4, and L2 traffic.
Signed-off-by: NAhmed Abdelsalam <amsalam20@gmail.com>
Acked-by: NDavid Lebrun <dlebrun@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

rt6_remove_exception_rt() is called under rcu_read_lock() only.

We lock rt6_exception_lock a bit later, so we do not hold
rt6_exception_lock yet.

Fixes: 8a14e46f ("net/ipv6: Fix missing rcu dereferences on from")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Cc: David Ahern <dsahern@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

kbuild test robot reported 2 uses of rt->from not properly accessed
using rcu_dereference:
1. add rcu_dereference_protected to rt6_remove_exception_rt and make
   sure it is always called with rcu lock held.

2. change rt6_do_redirect to take a reference on 'from' when accessed
   the first time so it can be used the sceond time outside of the lock

Fixes: a68886a6 ("net/ipv6: Make from in rt6_info rcu protected")
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot reported a suspicious rcu_dereference_check:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1b9/0x294 lib/dump_stack.c:113
  lockdep_rcu_suspicious+0x14a/0x153 kernel/locking/lockdep.c:4592
  rt6_check_expired+0x38b/0x3e0 net/ipv6/route.c:410
  ip6_negative_advice+0x67/0xc0 net/ipv6/route.c:2204
  dst_negative_advice include/net/sock.h:1786 [inline]
  sock_setsockopt+0x138f/0x1fe0 net/core/sock.c:1051
  __sys_setsockopt+0x2df/0x390 net/socket.c:1899
  SYSC_setsockopt net/socket.c:1914 [inline]
  SyS_setsockopt+0x34/0x50 net/socket.c:1911

Add rcu locking around call to rt6_check_expired in
ip6_negative_advice.

Fixes: a68886a6 ("net/ipv6: Make from in rt6_info rcu protected")
Reported-by: syzbot+2422c9e35796659d2273@syzkaller.appspotmail.com
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

KMSAN reported use of uninit-value that I tracked to lack
of proper size check on RTA_TABLE attribute.

I also believe RTA_PREFSRC lacks a similar check.

Fixes: 86872cb5 ("[IPv6] route: FIB6 configuration using struct fib6_config")
Fixes: c3968a85 ("ipv6: RTA_PREFSRC support for ipv6 route source address selection")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case of seg6 in encap mode, seg6_do_srh_encap() calls set_tun_src()
in order to set the src addr of outer IPv6 header.

The net_device is required for set_tun_src(). However calling ip6_dst_idev()
on dst_entry in case of IPv4 traffic results on the following bug.

Using just dst->dev should fix this BUG.

[  196.242461] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[  196.242975] PGD 800000010f076067 P4D 800000010f076067 PUD 10f060067 PMD 0
[  196.243329] Oops: 0000 [#1] SMP PTI
[  196.243468] Modules linked in: nfsd auth_rpcgss nfs_acl nfs lockd grace fscache sunrpc crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd input_leds glue_helper led_class pcspkr serio_raw mac_hid video autofs4 hid_generic usbhid hid e1000 i2c_piix4 ahci pata_acpi libahci
[  196.244362] CPU: 2 PID: 1089 Comm: ping Not tainted 4.16.0+ #1
[  196.244606] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[  196.244968] RIP: 0010:seg6_do_srh_encap+0x1ac/0x300
[  196.245236] RSP: 0018:ffffb2ce00b23a60 EFLAGS: 00010202
[  196.245464] RAX: 0000000000000000 RBX: ffff8c7f53eea300 RCX: 0000000000000000
[  196.245742] RDX: 0000f10000000000 RSI: ffff8c7f52085a6c RDI: ffff8c7f41166850
[  196.246018] RBP: ffffb2ce00b23aa8 R08: 00000000000261e0 R09: ffff8c7f41166800
[  196.246294] R10: ffffdce5040ac780 R11: ffff8c7f41166828 R12: ffff8c7f41166808
[  196.246570] R13: ffff8c7f52085a44 R14: ffffffffb73211c0 R15: ffff8c7e69e44200
[  196.246846] FS:  00007fc448789700(0000) GS:ffff8c7f59d00000(0000) knlGS:0000000000000000
[  196.247286] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  196.247526] CR2: 0000000000000000 CR3: 000000010f05a000 CR4: 00000000000406e0
[  196.247804] Call Trace:
[  196.247972]  seg6_do_srh+0x15b/0x1c0
[  196.248156]  seg6_output+0x3c/0x220
[  196.248341]  ? prandom_u32+0x14/0x20
[  196.248526]  ? ip_idents_reserve+0x6c/0x80
[  196.248723]  ? __ip_select_ident+0x90/0x100
[  196.248923]  ? ip_append_data.part.50+0x6c/0xd0
[  196.249133]  lwtunnel_output+0x44/0x70
[  196.249328]  ip_send_skb+0x15/0x40
[  196.249515]  raw_sendmsg+0x8c3/0xac0
[  196.249701]  ? _copy_from_user+0x2e/0x60
[  196.249897]  ? rw_copy_check_uvector+0x53/0x110
[  196.250106]  ? _copy_from_user+0x2e/0x60
[  196.250299]  ? copy_msghdr_from_user+0xce/0x140
[  196.250508]  sock_sendmsg+0x36/0x40
[  196.250690]  ___sys_sendmsg+0x292/0x2a0
[  196.250881]  ? _cond_resched+0x15/0x30
[  196.251074]  ? copy_termios+0x1e/0x70
[  196.251261]  ? _copy_to_user+0x22/0x30
[  196.251575]  ? tty_mode_ioctl+0x1c3/0x4e0
[  196.251782]  ? _cond_resched+0x15/0x30
[  196.251972]  ? mutex_lock+0xe/0x30
[  196.252152]  ? vvar_fault+0xd2/0x110
[  196.252337]  ? __do_fault+0x1f/0xc0
[  196.252521]  ? __handle_mm_fault+0xc1f/0x12d0
[  196.252727]  ? __sys_sendmsg+0x63/0xa0
[  196.252919]  __sys_sendmsg+0x63/0xa0
[  196.253107]  do_syscall_64+0x72/0x200
[  196.253305]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[  196.253530] RIP: 0033:0x7fc4480b0690
[  196.253715] RSP: 002b:00007ffde9f252f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  196.254053] RAX: ffffffffffffffda RBX: 0000000000000040 RCX: 00007fc4480b0690
[  196.254331] RDX: 0000000000000000 RSI: 000000000060a360 RDI: 0000000000000003
[  196.254608] RBP: 00007ffde9f253f0 R08: 00000000002d1e81 R09: 0000000000000002
[  196.254884] R10: 00007ffde9f250c0 R11: 0000000000000246 R12: 0000000000b22070
[  196.255205] R13: 20c49ba5e353f7cf R14: 431bde82d7b634db R15: 00007ffde9f278fe
[  196.255484] Code: a5 0f b6 45 c0 41 88 41 28 41 0f b6 41 2c 48 c1 e0 04 49 8b 54 01 38 49 8b 44 01 30 49 89 51 20 49 89 41 18 48 8b 83 b0 00 00 00 <48> 8b 30 49 8b 86 08 0b 00 00 48 8b 40 20 48 8b 50 08 48 0b 10
[  196.256190] RIP: seg6_do_srh_encap+0x1ac/0x300 RSP: ffffb2ce00b23a60
[  196.256445] CR2: 0000000000000000
[  196.256676] ---[ end trace 71af7d093603885c ]---

Fixes: 8936ef76 ("ipv6: sr: fix NULL pointer dereference when setting encap source address")
Signed-off-by: NAhmed Abdelsalam <amsalam20@gmail.com>
Acked-by: NDavid Lebrun <dlebrun@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dan reported an imbalance in fib6_check on use of f6i and checking
whether it is null. Since fib6_check is only called if f6i is non-null,
remove the unnecessary check.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a dst entry is created from a fib entry, the 'from' in rt6_info
is set to the fib entry. The 'from' reference is used most notably for
cookie checking - making sure stale dst entries are updated if the
fib entry is changed.

When a fib entry is deleted, the pcpu routes on it are walked releasing
the fib6_info reference. This is needed for the fib6_info cleanup to
happen and to make sure all device references are released in a timely
manner.

There is a race window when a FIB entry is deleted and the 'from' on the
pcpu route is dropped and the pcpu route hits a cookie check. Handle
this race using rcu on from.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Code move only; no functional change intended.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A later patch protects 'from' in rt6_info and this simplifies the
locking needed by it.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A later patch protects 'from' in rt6_info and this simplifies the
locking needed by it.

With the move, the fib6_info_hold for the uncached_rt is no longer
needed since the rcu_lock is still held.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

rt6_get_cookie_safe takes a fib6_info and checks the sernum of
the node. Update the name to reflect its purpose.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

rt6_clean_expires and rt6_set_expires are no longer used. Removed them.
rt6_update_expires has 1 caller in route.c, so move it from the header.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If ip6_convert_metrics() fails to allocate memory, it should not
overwrite rt->fib6_metrics or we risk a crash later as syzbot found.

BUG: KASAN: null-ptr-deref in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: null-ptr-deref in refcount_sub_and_test+0x92/0x330 lib/refcount.c:179
Read of size 4 at addr 0000000000000044 by task syzkaller832429/4487

CPU: 1 PID: 4487 Comm: syzkaller832429 Not tainted 4.16.0+ #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 kasan_report_error mm/kasan/report.c:352 [inline]
 kasan_report.cold.7+0x6d/0x2fe mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 refcount_sub_and_test+0x92/0x330 lib/refcount.c:179
 refcount_dec_and_test+0x1a/0x20 lib/refcount.c:212
 fib6_info_destroy+0x2d0/0x3c0 net/ipv6/ip6_fib.c:206
 fib6_info_release include/net/ip6_fib.h:304 [inline]
 ip6_route_info_create+0x677/0x3240 net/ipv6/route.c:3020
 ip6_route_add+0x23/0xb0 net/ipv6/route.c:3030
 inet6_rtm_newroute+0x142/0x160 net/ipv6/route.c:4406
 rtnetlink_rcv_msg+0x466/0xc10 net/core/rtnetlink.c:4648
 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4666
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x9f0/0xfa0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 ___sys_sendmsg+0x805/0x940 net/socket.c:2117
 __sys_sendmsg+0x115/0x270 net/socket.c:2155
 SYSC_sendmsg net/socket.c:2164 [inline]
 SyS_sendmsg+0x29/0x30 net/socket.c:2162
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Fixes: d4ead6b3 ("net/ipv6: move metrics from dst to rt6_info")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: David Ahern <dsa@cumulusnetworks.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Acked-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Eric noticed that __ipv6_ifa_notify is called under rcu_read_lock, so
the gfp argument to addrconf_prefix_route can not be GFP_KERNEL.

While scrubbing other calls I noticed addrconf_addr_gen has one
place with GFP_ATOMIC that can be GFP_KERNEL.

Fixes: acb54e3c ("net/ipv6: Add gfp_flags to route add functions")
Reported-by: syzbot+2add39b05179b31f912f@syzkaller.appspotmail.com
Reported-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fib6_idev can be obtained from __in6_dev_get on the nexthop device
rather than caching it in the fib6_info. Remove it.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Prior to 4832c30d ("net: ipv6: put host and anycast routes on device
with address") host routes and anycast routes were installed with the
device set to loopback (or VRF device once that feature was added). In the
older code dst.dev was set to loopback (needed for packet tx) and rt6i_idev
was used to denote the actual interface.

Commit 4832c30d changed the code to have dst.dev pointing to the real
device with the switch to lo or vrf device done on dst clones. As a
consequence of this change a couple of device checks during route lookups
are no longer needed. Remove them.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

aca_idev has only 1 user - inet6_fill_ifacaddr - and it only
wants the device index which can be extracted from the fib6_info
nexthop.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

addrconf_dst_alloc now returns a fib6_info. Update the name
and its users to reflect the change.

Rename only; no functional change intended.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Change the prefix for fib6_info struct elements from rt6i_ to fib6_.
rt6i_pcpu and rt6i_exception_bucket are left as is given that they
point to rt6_info entries.

Rename only; not functional change intended.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move these options inside the scope of the 'if' NF_TABLES and
NF_TABLES_IPV6 dependencies. This patch fixes:

   net/ipv6/netfilter/nft_chain_nat_ipv6.o: In function `nft_nat_do_chain':
>> net/ipv6/netfilter/nft_chain_nat_ipv6.c:37: undefined reference to `nft_do_chain'
   net/ipv6/netfilter/nft_chain_nat_ipv6.o: In function `nft_chain_nat_ipv6_exit':
>> net/ipv6/netfilter/nft_chain_nat_ipv6.c:94: undefined reference to `nft_unregister_chain_type'
   net/ipv6/netfilter/nft_chain_nat_ipv6.o: In function `nft_chain_nat_ipv6_init':
>> net/ipv6/netfilter/nft_chain_nat_ipv6.c:87: undefined reference to `nft_register_chain_type'

that happens with:

CONFIG_NF_TABLES=m
CONFIG_NFT_CHAIN_NAT_IPV6=y

Fixes: 02c7b25e ("netfilter: nf_tables: build-in filter chain type")
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

lockdep does not know that the locks used by IPv4 defrag
and IPv6 reassembly units are of different classes.

It complains because of following chains :

1) sch_direct_xmit()        (lock txq->_xmit_lock)
    dev_hard_start_xmit()
     xmit_one()
      dev_queue_xmit_nit()
       packet_rcv_fanout()
        ip_check_defrag()
         ip_defrag()
          spin_lock()     (lock frag queue spinlock)

2) ip6_input_finish()
    ipv6_frag_rcv()       (lock frag queue spinlock)
     ip6_frag_queue()
      icmpv6_param_prob() (lock txq->_xmit_lock at some point)

We could add lockdep annotations, but we also can make sure IPv6
calls icmpv6_param_prob() only after the release of the frag queue spinlock,
since this naturally makes frag queue spinlock a leaf in lock hierarchy.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Drop unneeded elements from rt6_info struct and rearrange layout to
something more relevant for the data path.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Convert all code paths referencing a FIB entry from
rt6_info to fib6_info.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Last step before flipping the data type for FIB entries:
- use fib6_info_alloc to create FIB entries in ip6_route_info_create
  and addrconf_dst_alloc
- use fib6_info_release in place of dst_release, ip6_rt_put and
  rt6_release
- remove the dst_hold before calling __ip6_ins_rt or ip6_del_rt
- when purging routes, drop per-cpu routes
- replace inc and dec of rt6i_ref with fib6_info_hold and fib6_info_release
- use rt->from since it points to the FIB entry
- drop references to exception bucket, fib6_metrics and per-cpu from
  dst entries (those are relevant for fib entries only)
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add fib6_info struct and alloc, destroy, hold and release helpers.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPv6 FIB will only contain FIB entries with exception routes added to
the FIB entry. Once this transformation is complete, FIB lookups will
return a fib6_info with the lookup functions still returning a dst
based rt6_info. The current code uses rt6_info for both paths and
overloads the rt6_info variable usually called 'rt'.

This patch introduces a new 'f6i' variable name for the result of the FIB
lookup and keeps 'rt' as the dst based return variable. 'f6i' becomes a
fib6_info in a later patch which is why it is introduced as f6i now;
avoids the additional churn in the later patch.

In addition, remove RTF_CACHE and dst checks from fib6 add and delete
since they can not happen now and will never happen after the data
type flip.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Most FIB entries can be added using memory allocated with GFP_KERNEL.
Add gfp_flags to ip6_route_add and addrconf_dst_alloc. Code paths that
can be reached from the packet path (e.g., ndisc and autoconfig) or
atomic notifiers use GFP_ATOMIC; paths from user context (adding
addresses and routes) use GFP_KERNEL.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The router discovery code has a FIB entry and wants to validate the
gateway has a neighbor entry. Refactor the existing dst_neigh_lookup
for IPv6 and create a new function that takes the gateway and device
and returns a neighbor entry. Use the new function in
ndisc_router_discovery to validate the gateway.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Continuing to wean FIB paths off of dst_entry, use a bool to hold
requests for certain dst settings. Add a helper to convert the
flags to DST flags when a FIB entry is converted to a dst_entry.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ip6_pol_route_lookup is the lookup function for ip6_route_lookup and
rt6_lookup. At the moment it returns either a reference to a FIB entry
or a cached exception. To move FIB entries to a separate struct, this
lookup function needs to convert FIB entries to an rt6_info that is
returned to the caller.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>