This avoids an indirect call per syscall for common ipv6 transports
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This will simplify indirect call wrapper invocation in the following
patch.

No functional change intended, any - out-of-tree - IPv6 user of
inet_{recv,send}msg can keep using the existing functions.

SCTP code still uses the existing version even for ipv6: as this series
will not add ICW for SCTP, moving to the new helper would not give
any benefit.

The only other in-kernel user of inet_{recv,send}msg is
pvcalls_conn_back_read(), but psvcalls explicitly creates only IPv4 socket,
so no need to update that code path, too.

v1 -> v2: drop inet6_{recv,send}msg declaration from header file,
   prefer ICW macro instead
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use blackhole_netdev instead of 'lo' device with lower MTU when marking
dst "dead".
Signed-off-by: NMahesh Bandewar <maheshb@google.com>
Tested-by: NMichael Chan <michael.chan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

/proc/sys/net/ipv6/flowlabel_reflect assumes written value to be in the
range of 0 to 3. Use proc_dointvec_minmax instead of proc_dointvec.

Fixes: 323a53c4 ("ipv6: tcp: enable flowlabel reflection in some RST packets")
Signed-off-by: NEiichi Tsukata <devel@etsukata.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Extend flowlabel_reflect bitmask to allow conditional
reflection of incoming flowlabels in echo replies.

Note this has precedence against auto flowlabels.

Add flowlabel_reflect enum to replace hard coded
values.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Gateway validation does not need a dst_entry, it only needs the fib
entry to validate the gateway resolution and egress device. So,
convert ip6_nh_lookup_table from ip6_pol_route to fib6_table_lookup
and ip6_route_check_nh to use fib6_lookup over rt6_lookup.

ip6_pol_route is a call to fib6_table_lookup and if successful a call
to fib6_select_path. From there the exception cache is searched for an
entry or a dst_entry is created to return to the caller. The exception
entry is not relevant for gateway validation, so what matters are the
calls to fib6_table_lookup and then fib6_select_path.

Similarly, rt6_lookup can be replaced with a call to fib6_lookup with
RT6_LOOKUP_F_IFACE set in flags. Again, the exception cache search is
not relevant, only the lookup with path selection. The primary difference
in the lookup paths is the use of rt6_select with fib6_lookup versus
rt6_device_match with rt6_lookup. When you remove complexities in the
rt6_select path, e.g.,
1. saddr is not set for gateway validation, so RT6_LOOKUP_F_HAS_SADDR
   is not relevant
2. rt6_check_neigh is not called so that removes the RT6_NUD_FAIL_DO_RR
   return and round-robin logic.

the code paths are believed to be equivalent for the given use case -
validate the gateway and optionally given the device. Furthermore, it
aligns the validation with onlink code path and the lookup path actually
used for rx and tx.

Adjust the users, ip6_route_check_nh_onlink and ip6_route_check_nh to
handle a fib6_info vs a rt6_info when performing validation checks.

Existing selftests fib-onlink-tests.sh and fib_tests.sh are used to
verify the changes.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Reviewed-by: NWei Wang <weiwan@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The scenario is the following: the user uses a raw socket to send an ipv6
packet, destinated to a not-connected network, and specify a connected nh.
Here is the corresponding python script to reproduce this scenario:

 import socket
 IPPROTO_RAW = 255
 send_s = socket.socket(socket.AF_INET6, socket.SOCK_RAW, IPPROTO_RAW)
 # scapy
 # p = IPv6(src='fd00:100::1', dst='fd00:200::fa')/ICMPv6EchoRequest()
 # str(p)
 req = b'`\x00\x00\x00\x00\x08:@\xfd\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\xfd\x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xfa\x80\x00\x81\xc0\x00\x00\x00\x00'
 send_s.sendto(req, ('fd00:175::2', 0, 0, 0))

fd00:175::/64 is a connected route and fd00:200::fa is not a connected
host.

With this scenario, the kernel starts by sending a NS to resolve
fd00:175::2. When it receives the NA, it flushes its queue and try to send
the initial packet. But instead of sending it, it sends another NS to
resolve fd00:200::fa, which obvioulsy fails, thus the packet is dropped. If
the user sends again the packet, it now uses the right nh (fd00:175::2).

The problem is that ip6_dst_lookup_neigh() uses the rt6i_gateway, which is
:: because the associated route is a connected route, thus it uses the dst
addr of the packet. Let's use rt6_nexthop() to choose the right nh.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is no functional change in this patch, it only prepares the next one.

rt6_nexthop() will be used by ip6_dst_lookup_neigh(), which uses const
variables.
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Reported-by: Nkbuild test robot <lkp@intel.com>
Acked-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot reminded us that rt6_nh_dump_exceptions() needs to be called
with rcu_read_lock()

net/ipv6/route.c:1593 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
2 locks held by syz-executor609/8966:
 #0: 00000000b7dbe288 (rtnl_mutex){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199
 #1: 00000000f2d87c21 (&(&tb->tb6_lock)->rlock){+...}, at: spin_lock_bh include/linux/spinlock.h:343 [inline]
 #1: 00000000f2d87c21 (&(&tb->tb6_lock)->rlock){+...}, at: fib6_dump_table.isra.0+0x37e/0x570 net/ipv6/ip6_fib.c:533

stack backtrace:
CPU: 0 PID: 8966 Comm: syz-executor609 Not tainted 5.2.0-rc5+ #43
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+0x172/0x1f0 lib/dump_stack.c:113
 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5250
 fib6_nh_get_excptn_bucket+0x18e/0x1b0 net/ipv6/route.c:1593
 rt6_nh_dump_exceptions+0x45/0x4d0 net/ipv6/route.c:5541
 rt6_dump_route+0x904/0xc50 net/ipv6/route.c:5640
 fib6_dump_node+0x168/0x280 net/ipv6/ip6_fib.c:467
 fib6_walk_continue+0x4a9/0x8e0 net/ipv6/ip6_fib.c:1986
 fib6_walk+0x9d/0x100 net/ipv6/ip6_fib.c:2034
 fib6_dump_table.isra.0+0x38a/0x570 net/ipv6/ip6_fib.c:534
 inet6_dump_fib+0x93c/0xb00 net/ipv6/ip6_fib.c:624
 rtnl_dump_all+0x295/0x490 net/core/rtnetlink.c:3445
 netlink_dump+0x558/0xfb0 net/netlink/af_netlink.c:2244
 __netlink_dump_start+0x5b1/0x7d0 net/netlink/af_netlink.c:2352
 netlink_dump_start include/linux/netlink.h:226 [inline]
 rtnetlink_rcv_msg+0x73d/0xb00 net/core/rtnetlink.c:5182
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5237
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:665
 sock_write_iter+0x27c/0x3e0 net/socket.c:994
 call_write_iter include/linux/fs.h:1872 [inline]
 new_sync_write+0x4d3/0x770 fs/read_write.c:483
 __vfs_write+0xe1/0x110 fs/read_write.c:496
 vfs_write+0x20c/0x580 fs/read_write.c:558
 ksys_write+0x14f/0x290 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:620
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4401b9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc8e134978 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401b9
RDX: 000000000000001c RSI: 0000000020000000 RDI: 00

Fixes: 1e47b483 ("ipv6: Dump route exceptions if requested")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Stefano Brivio <sbrivio@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Reviewed-by: NStefano Brivio <sbrivio@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

/proc/sys/net/ipv6/route/skip_notify_on_dev_down assumes given value to be
0 or 1. Use proc_dointvec_minmax instead of proc_dointvec.

Fixes: 7c6bb7d2 ("net/ipv6: Add knob to skip DELROUTE message ondevice down")
Signed-off-by: NEiichi Tsukata <devel@etsukata.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we perform an inexact match on FIB nodes via fib6_locate_1(), longer
prefixes will be preferred to shorter ones. However, it might happen that
a node, with higher fn_bit value than some other, has no valid routing
information.

In this case, we'll pick that node, but it will be discarded by the check
on RTN_RTINFO in fib6_locate(), and we might miss nodes with valid routing
information but with lower fn_bit value.

This is apparent when a routing exception is created for a default route:
 # ip -6 route list
 fc00:1::/64 dev veth_A-R1 proto kernel metric 256 pref medium
 fc00:2::/64 dev veth_A-R2 proto kernel metric 256 pref medium
 fc00:4::1 via fc00:2::2 dev veth_A-R2 metric 1024 pref medium
 fe80::/64 dev veth_A-R1 proto kernel metric 256 pref medium
 fe80::/64 dev veth_A-R2 proto kernel metric 256 pref medium
 default via fc00:1::2 dev veth_A-R1 metric 1024 pref medium
 # ip -6 route list cache
 fc00:4::1 via fc00:2::2 dev veth_A-R2 metric 1024 expires 593sec mtu 1500 pref medium
 fc00:3::1 via fc00:1::2 dev veth_A-R1 metric 1024 expires 593sec mtu 1500 pref medium
 # ip -6 route flush cache    # node for default route is discarded
 Failed to send flush request: No such process
 # ip -6 route list cache
 fc00:3::1 via fc00:1::2 dev veth_A-R1 metric 1024 expires 586sec mtu 1500 pref medium

Check right away if the node has a RTN_RTINFO flag, before replacing the
'prev' pointer, that indicates the longest matching prefix found so far.

Fixes: 38fbeeee ("ipv6: prepare fib6_locate() for exception table")
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit 2b760fcf ("ipv6: hook up exception table to store dst
cache"), route exceptions reside in a separate hash table, and won't be
found by walking the FIB, so they won't be dumped to userspace on a
RTM_GETROUTE message.

This causes 'ip -6 route list cache' and 'ip -6 route flush cache' to
have no function anymore:

 # ip -6 route get fc00:3::1
 fc00:3::1 via fc00:1::2 dev veth_A-R1 src fc00:1::1 metric 1024 expires 539sec mtu 1400 pref medium
 # ip -6 route get fc00:4::1
 fc00:4::1 via fc00:2::2 dev veth_A-R2 src fc00:2::1 metric 1024 expires 536sec mtu 1500 pref medium
 # ip -6 route list cache
 # ip -6 route flush cache
 # ip -6 route get fc00:3::1
 fc00:3::1 via fc00:1::2 dev veth_A-R1 src fc00:1::1 metric 1024 expires 520sec mtu 1400 pref medium
 # ip -6 route get fc00:4::1
 fc00:4::1 via fc00:2::2 dev veth_A-R2 src fc00:2::1 metric 1024 expires 519sec mtu 1500 pref medium

because iproute2 lists cached routes using RTM_GETROUTE, and flushes them
by listing all the routes, and deleting them with RTM_DELROUTE one by one.

If cached routes are requested using the RTM_F_CLONED flag together with
strict checking, or if no strict checking is requested (and hence we can't
consistently apply filters), look up exceptions in the hash table
associated with the current fib6_info in rt6_dump_route(), and, if present
and not expired, add them to the dump.

We might be unable to dump all the entries for a given node in a single
message, so keep track of how many entries were handled for the current
node in fib6_walker, and skip that amount in case we start from the same
partially dumped node.

When a partial dump restarts, as the starting node might change when
'sernum' changes, we have no guarantee that we need to skip the same
amount of in-node entries. Therefore, we need two counters, and we need to
zero the in-node counter if the node from which the dump is resumed
differs.

Note that, with the current version of iproute2, this only fixes the
'ip -6 route list cache': on a flush command, iproute2 doesn't pass
RTM_F_CLONED and, due to this inconsistency, 'ip -6 route flush cache' is
still unable to fetch the routes to be flushed. This will be addressed in
a patch for iproute2.

To flush cached routes, a procfs entry could be introduced instead: that's
how it works for IPv4. We already have a rt6_flush_exception() function
ready to be wired to it. However, this would not solve the issue for
listing.

Versions of iproute2 and kernel tested:

                    iproute2
kernel             4.14.0   4.15.0   4.19.0   5.0.0   5.1.0    5.1.0, patched
 3.18    list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.4     list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.9     list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.14    list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.15    list
         flush
 4.19    list
         flush
 5.0     list
         flush
 5.1     list
         flush
 with    list        +        +        +        +       +            +
 fix     flush       +        +        +                             +

v7:
  - Explain usage of "skip" counters in commit message (suggested by
    David Ahern)

v6:
  - Rebase onto net-next, use recently introduced nexthop walker
  - Make rt6_nh_dump_exceptions() a separate function (suggested by David
    Ahern)

v5:
  - Use dump_routes and dump_exceptions from filter, ignore NLM_F_MATCH,
    update test results (flushing works with iproute2 < 5.0.0 now)

v4:
  - Split NLM_F_MATCH and strict check handling in separate patches
  - Filter routes using RTM_F_CLONED: if it's not set, only return
    non-cached routes, and if it's set, only return cached routes:
    change requested by David Ahern and Martin Lau. This implies that
    iproute2 needs a separate patch to be able to flush IPv6 cached
    routes. This is not ideal because we can't fix the breakage caused
    by 2b760fcf entirely in kernel. However, two years have passed
    since then, and this makes it more tolerable

v3:
  - More descriptive comment about expired exceptions in rt6_dump_route()
  - Swap return values of rt6_dump_route() (suggested by Martin Lau)
  - Don't zero skip_in_node in case we don't dump anything in a given pass
    (also suggested by Martin Lau)
  - Remove check on RTM_F_CLONED altogether: in the current UAPI semantic,
    it's just a flag to indicate the route was cloned, not to filter on
    routes

v2: Add tracking of number of entries to be skipped in current node after
    a partial dump. As we restart from the same node, if not all the
    exceptions for a given node fit in a single message, the dump will
    not terminate, as suggested by Martin Lau. This is a concrete
    possibility, setting up a big number of exceptions for the same route
    actually causes the issue, suggested by David Ahern.
Reported-by: NJianlin Shi <jishi@redhat.com>
Fixes: 2b760fcf ("ipv6: hook up exception table to store dst cache")
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the next patch, we are going to add optional dump of exceptions to
rt6_dump_route().

Change the return code of rt6_dump_route() to accomodate partial node
dumps: we might dump multiple routes per node, and might be able to dump
only a given number of them, so fib6_dump_node() will need to know how
many routes have been dumped on partial dump, to restart the dump from the
point where it was interrupted.

Note that fib6_dump_node() is the only caller and already handles all
non-negative return codes as success: those become -1 to signal that we're
done with the node. If we fail, return 0, as we were unable to dump the
single route in the node, but we're not done with it.
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If fc_nh_id isn't set, we shouldn't try to match against it. This
actually matters just for the RTF_CACHE below (where this case is
already handled): if iproute2 gets a route exception and tries to
delete it, it won't reference it by fc_nh_id, even if a nexthop
object might be associated to the originating route.

Fixes: 5b98324e ("ipv6: Allow routes to use nexthop objects")
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 08e814c9: as we
are preparing to fix listing and dumping of IPv6 cached routes, we
need to allow RTM_F_CLONED as a flag to match routes against while
dumping them.
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The following patches add back the ability to dump IPv4 and IPv6 exception
routes, and we need to allow selection of regular routes or exceptions.

Use RTM_F_CLONED as filter to decide whether to dump routes or exceptions:
iproute2 passes it in dump requests (except for IPv6 cache flush requests,
this will be fixed in iproute2) and this used to work as long as
exceptions were stored directly in the FIB, for both IPv4 and IPv6.

Caveat: if strict checking is not requested (that is, if the dump request
doesn't go through ip_valid_fib_dump_req()), we can't filter on protocol,
tables or route types.

In this case, filtering on RTM_F_CLONED would be inconsistent: we would
fix 'ip route list cache' by returning exception routes and at the same
time introduce another bug in case another selector is present, e.g. on
'ip route list cache table main' we would return all exception routes,
without filtering on tables.

Keep this consistent by applying no filters at all, and dumping both
routes and exceptions, if strict checking is not requested. iproute2
currently filters results anyway, and no unwanted results will be
presented to the user. The kernel will just dump more data than needed.

v7: No changes

v6: Rebase onto net-next, no changes

v5: New patch: add dump_routes and dump_exceptions flags in filter and
    simply clear the unwanted one if strict checking is enabled, don't
    ignore NLM_F_MATCH and don't set filter_set if NLM_F_MATCH is set.
    Skip filtering altogether if no strict checking is requested:
    selecting routes or exceptions only would be inconsistent with the
    fact we can't filter on tables.
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For tx path, in most cases, we still have to take refcnt on the dst
cause the caller is caching the dst somewhere. But it still is
beneficial to make use of RT6_LOOKUP_F_DST_NOREF flag while doing the
route lookup. It is cause this flag prevents manipulating refcnt on
net->ipv6.ip6_null_entry when doing fib6_rule_lookup() to traverse each
routing table. The null_entry is a shared object and constant updates on
it cause false sharing.

We converted the current major lookup function ip6_route_output_flags()
to make use of RT6_LOOKUP_F_DST_NOREF.

Together with the change in the rx path, we see noticable performance
boost:
I ran synflood tests between 2 hosts under the same switch. Both hosts
have 20G mlx NIC, and 8 tx/rx queues.
Sender sends pure SYN flood with random src IPs and ports using trafgen.
Receiver has a simple TCP listener on the target port.
Both hosts have multiple custom rules:
- For incoming packets, only local table is traversed.
- For outgoing packets, 3 tables are traversed to find the route.
The packet processing rate on the receiver is as follows:
- Before the fix: 3.78Mpps
- After the fix:  5.50Mpps
Signed-off-by: NWei Wang <weiwan@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ip6_route_input() is the key function to do the route lookup in the
rx data path. All the callers to this function are already holding rcu
lock. So it is fairly easy to convert it to not take refcnt on the dst:
We pass in flag RT6_LOOKUP_F_DST_NOREF and do skb_dst_set_noref().
This saves a few atomic inc or dec operations and should boost
performance overall.
This also makes the logic more aligned with v4.
Signed-off-by: NWei Wang <weiwan@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NMahesh Bandewar <maheshb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch specifically converts the rule lookup logic to honor this
flag and not release refcnt when traversing each rule and calling
lookup() on each routing table.
Similar to previous patch, we also need some special handling of dst
entries in uncached list because there is always 1 refcnt taken for them
even if RT6_LOOKUP_F_DST_NOREF flag is set.
Signed-off-by: NWei Wang <weiwan@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Initialize rt6->rt6i_uncached on the following pre-allocated dsts:
net->ipv6.ip6_null_entry
net->ipv6.ip6_prohibit_entry
net->ipv6.ip6_blk_hole_entry

This is a preparation patch for later commits to be able to distinguish
dst entries in uncached list by doing:
!list_empty(rt6->rt6i_uncached)
Signed-off-by: NWei Wang <weiwan@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NMahesh Bandewar <maheshb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This new flag is to instruct the route lookup function to not take
refcnt on the dst entry. The user which does route lookup with this flag
must properly use rcu protection.
ip6_pol_route() is the major route lookup function for both tx and rx
path.
In this function:
Do not take refcnt on dst if RT6_LOOKUP_F_DST_NOREF flag is set, and
directly return the route entry. The caller should be holding rcu lock
when using this flag, and decide whether to take refcnt or not.

One note on the dst cache in the uncached_list:
As uncached_list does not consume refcnt, one refcnt is always returned
back to the caller even if RT6_LOOKUP_F_DST_NOREF flag is set.
Uncached dst is only possible in the output path. So in such call path,
caller MUST check if the dst is in the uncached_list before assuming
that there is no refcnt taken on the returned dst.
Signed-off-by: NWei Wang <weiwan@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NMahesh Bandewar <maheshb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When user space sends invalid information in RTA_MULTIPATH, the nexthop
list in ip6_route_multipath_add() is empty and 'rt_notif' is set to
NULL.

The code that emits the in-kernel notifications does not check for this
condition, which results in a NULL pointer dereference [1].

Fix this by bailing earlier in the function if the parsed nexthop list
is empty. This is consistent with the corresponding IPv4 code.

v2:
* Check if parsed nexthop list is empty and bail with extack set

[1]
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 9190 Comm: syz-executor149 Not tainted 5.2.0-rc5+ #38
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:call_fib6_multipath_entry_notifiers+0xd1/0x1a0
net/ipv6/ip6_fib.c:396
Code: 8b b5 30 ff ff ff 48 c7 85 68 ff ff ff 00 00 00 00 48 c7 85 70 ff ff
ff 00 00 00 00 89 45 88 4c 89 e0 48 c1 e8 03 4c 89 65 80 <42> 80 3c 28 00
0f 85 9a 00 00 00 48 b8 00 00 00 00 00 fc ff df 4d
RSP: 0018:ffff88809788f2c0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff11012f11e59 RCX: 00000000ffffffff
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88809788f390 R08: ffff88809788f8c0 R09: 000000000000000c
R10: ffff88809788f5d8 R11: ffff88809788f527 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff88809788f8c0 R15: ffffffff89541d80
FS:  000055555632c880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000080 CR3: 000000009ba7c000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  ip6_route_multipath_add+0xc55/0x1490 net/ipv6/route.c:5094
  inet6_rtm_newroute+0xed/0x180 net/ipv6/route.c:5208
  rtnetlink_rcv_msg+0x463/0xb00 net/core/rtnetlink.c:5219
  netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
  rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5237
  netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
  netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328
  netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1917
  sock_sendmsg_nosec net/socket.c:646 [inline]
  sock_sendmsg+0xd7/0x130 net/socket.c:665
  ___sys_sendmsg+0x803/0x920 net/socket.c:2286
  __sys_sendmsg+0x105/0x1d0 net/socket.c:2324
  __do_sys_sendmsg net/socket.c:2333 [inline]
  __se_sys_sendmsg net/socket.c:2331 [inline]
  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2331
  do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4401f9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc09fd0028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401f9
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a80
R13: 0000000000401b10 R14: 0000000000000000 R15: 0000000000000000

Reported-by: syzbot+382566d339d52cd1a204@syzkaller.appspotmail.com
Fixes: ebee3cad ("ipv6: Add IPv6 multipath notifications for add / replace")
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NJiri Pirko <jiri@mellanox.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When either CONFIG_IPV6 or CONFIG_SYN_COOKIES are disabled, the kernel
fails to build:

include/linux/netfilter_ipv6.h:180:9: error: implicit declaration of function '__cookie_v6_init_sequence'
      [-Werror,-Wimplicit-function-declaration]
        return __cookie_v6_init_sequence(iph, th, mssp);
include/linux/netfilter_ipv6.h:194:9: error: implicit declaration of function '__cookie_v6_check'
      [-Werror,-Wimplicit-function-declaration]
        return __cookie_v6_check(iph, th, cookie);
net/ipv6/netfilter.c:237:26: error: use of undeclared identifier '__cookie_v6_init_sequence'; did you mean 'cookie_init_sequence'?
net/ipv6/netfilter.c:238:21: error: use of undeclared identifier '__cookie_v6_check'; did you mean '__cookie_v4_check'?

Fix the IS_ENABLED() checks to match the function declaration
and definitions for these.

Fixes: 3006a522 ("netfilter: synproxy: remove module dependency on IPv6 SYNPROXY")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

A user reported that routes are getting installed with type 0 (RTN_UNSPEC)
where before the routes were RTN_UNICAST. One example is from accel-ppp
which apparently still uses the ioctl interface and does not set
rtmsg_type. Another is the netlink interface where ipv6 does not require
rtm_type to be set (v4 does). Prior to the commit in the Fixes tag the
ipv6 stack converted type 0 to RTN_UNICAST, so restore that behavior.

Fixes: e8478e80 ("net/ipv6: Save route type in rt6_info")
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot reported another issue caused by my recent patches. [1]

The issue here is that fqdir_exit() is initiating a work queue
and immediately returns. A bit later cleanup_net() was able
to free the MIB (percpu data) and the whole struct net was freed,
but we had active frag timers that fired and triggered use-after-free.

We need to make sure that timers can catch fqdir->dead being set,
to bailout.

Since RCU is used for the reader side, this means
we want to respect an RCU grace period between these operations :

1) qfdir->dead = 1;

2) netns dismantle (freeing of various data structure)

This patch uses new new (struct pernet_operations)->pre_exit
infrastructure to ensures a full RCU grace period
happens between fqdir_pre_exit() and fqdir_exit()

This also means we can use a regular work queue, we no
longer need rcu_work.

Tested:

$ time for i in {1..1000}; do unshare -n /bin/false;done

real	0m2.585s
user	0m0.160s
sys	0m2.214s

[1]

BUG: KASAN: use-after-free in ip_expire+0x73e/0x800 net/ipv4/ip_fragment.c:152
Read of size 8 at addr ffff88808b9fe330 by task syz-executor.4/11860

CPU: 1 PID: 11860 Comm: syz-executor.4 Not tainted 5.2.0-rc2+ #22
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 ip_expire+0x73e/0x800 net/ipv4/ip_fragment.c:152
 call_timer_fn+0x193/0x720 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers kernel/time/timer.c:1685 [inline]
 __run_timers kernel/time/timer.c:1653 [inline]
 run_timer_softirq+0x66f/0x1740 kernel/time/timer.c:1698
 __do_softirq+0x25c/0x94c kernel/softirq.c:293
 invoke_softirq kernel/softirq.c:374 [inline]
 irq_exit+0x180/0x1d0 kernel/softirq.c:414
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1068
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
 </IRQ>
RIP: 0010:tomoyo_domain_quota_is_ok+0x131/0x540 security/tomoyo/util.c:1035
Code: 24 4c 3b 65 d0 0f 84 9c 00 00 00 e8 19 1d 73 fe 49 8d 7c 24 18 48 ba 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 0f b6 04 10 <48> 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 69 03 00 00 41 0f b6 5c
RSP: 0018:ffff88806ae079c0 EFLAGS: 00000a02 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: 0000000000000010 RCX: ffffc9000e655000
RDX: dffffc0000000000 RSI: ffffffff82fd88a7 RDI: ffff888086202398
RBP: ffff88806ae07a00 R08: ffff88808b6c8700 R09: ffffed100d5c0f4d
R10: ffffed100d5c0f4c R11: 0000000000000000 R12: ffff888086202380
R13: 0000000000000030 R14: 00000000000000d3 R15: 0000000000000000
 tomoyo_supervisor+0x2e8/0xef0 security/tomoyo/common.c:2087
 tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline]
 tomoyo_path_number_perm+0x42f/0x520 security/tomoyo/file.c:734
 tomoyo_file_ioctl+0x23/0x30 security/tomoyo/tomoyo.c:335
 security_file_ioctl+0x77/0xc0 security/security.c:1370
 ksys_ioctl+0x57/0xd0 fs/ioctl.c:711
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4592c9
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f8db5e44c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004592c9
RDX: 0000000020000080 RSI: 00000000000089f1 RDI: 0000000000000006
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8db5e456d4
R13: 00000000004cc770 R14: 00000000004d5cd8 R15: 00000000ffffffff

Allocated by task 9047:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:497
 slab_post_alloc_hook mm/slab.h:437 [inline]
 slab_alloc mm/slab.c:3326 [inline]
 kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3488
 kmem_cache_zalloc include/linux/slab.h:732 [inline]
 net_alloc net/core/net_namespace.c:386 [inline]
 copy_net_ns+0xed/0x340 net/core/net_namespace.c:426
 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206
 ksys_unshare+0x440/0x980 kernel/fork.c:2692
 __do_sys_unshare kernel/fork.c:2760 [inline]
 __se_sys_unshare kernel/fork.c:2758 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:2758
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 2541:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3432 [inline]
 kmem_cache_free+0x86/0x260 mm/slab.c:3698
 net_free net/core/net_namespace.c:402 [inline]
 net_drop_ns.part.0+0x70/0x90 net/core/net_namespace.c:409
 net_drop_ns net/core/net_namespace.c:408 [inline]
 cleanup_net+0x538/0x960 net/core/net_namespace.c:571
 process_one_work+0x989/0x1790 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff88808b9fe100
 which belongs to the cache net_namespace of size 6784
The buggy address is located 560 bytes inside of
 6784-byte region [ffff88808b9fe100, ffff88808b9ffb80)
The buggy address belongs to the page:
page:ffffea00022e7f80 refcount:1 mapcount:0 mapping:ffff88821b6f60c0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea000256f288 ffffea0001bbef08 ffff88821b6f60c0
raw: 0000000000000000 ffff88808b9fe100 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808b9fe200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808b9fe280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808b9fe300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88808b9fe380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808b9fe400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: 3c8fc878 ("inet: frags: rework rhashtable dismantle")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NEnrico Weigelt <info@metux.net>
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NAllison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Both listeners - mlxsw and netdevsim - of IPv6 FIB notifications are now
ready to handle IPv6 multipath notifications.

Therefore, stop ignoring such notifications in both drivers and stop
sending notification for each added / deleted nexthop.

v2:
* Remove 'multipath_rt' from 'struct fib6_entry_notifier_info'
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If all the nexthops of a multipath route are being deleted, send one
notification for the entire route, instead of one per-nexthop.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Emit a notification when a multipath routes is added or replace.

Note that unlike the replace notifications sent from fib6_add_rt2node(),
it is possible we are sending a 'FIB_EVENT_ENTRY_REPLACE' when a route
was merely added and not replaced.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Extend the IPv6 FIB notifier info with number of sibling routes being
notified.

This will later allow listeners to process one notification for a
multipath routes instead of N, where N is the number of nexthops.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add common functions into nf_synproxy_core.c to prepare for nftables support.
The prototypes of the functions used by {ipt, ip6t}_SYNPROXY are in the new
file nf_synproxy.h
Signed-off-by: NFernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This is a prerequisite for the infrastructure module NETFILTER_SYNPROXY.
The new module is needed to avoid duplicated code for the SYNPROXY
nftables support.
Signed-off-by: NFernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This was originally passed through to the VRF logic in compute_score().
But that logic has now been replaced by udp_sk_bound_dev_eq() and so
this code is no longer used or needed.
Signed-off-by: NTim Beale <timbeale@catalyst.net.nz>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Originally this was used by the VRF logic in compute_score(), but that
was later replaced by udp_sk_bound_dev_eq() and the parameter became
unused.

Note this change adds an 'unused variable' compiler warning that will be
removed in the next patch (I've split the removal in two to make review
slightly easier).
Signed-off-by: NTim Beale <timbeale@catalyst.net.nz>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If we want to set a EDT time for the skb we want to send
via ip_send_unicast_reply(), we have to pass a new parameter
and initialize ipc.sockc.transmit_time with it.

This fixes the EDT time for ACK/RST packets sent on behalf of
a TIME_WAIT socket.

Fixes: a842fe14 ("tcp: add optional per socket transmit delay")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Adding delays to TCP flows is crucial for studying behavior
of TCP stacks, including congestion control modules.

Linux offers netem module, but it has unpractical constraints :
- Need root access to change qdisc
- Hard to setup on egress if combined with non trivial qdisc like FQ
- Single delay for all flows.

EDT (Earliest Departure Time) adoption in TCP stack allows us
to enable a per socket delay at a very small cost.

Networking tools can now establish thousands of flows, each of them
with a different delay, simulating real world conditions.

This requires FQ packet scheduler or a EDT-enabled NIC.

This patchs adds TCP_TX_DELAY socket option, to set a delay in
usec units.

  unsigned int tx_delay = 10000; /* 10 msec */

  setsockopt(fd, SOL_TCP, TCP_TX_DELAY, &tx_delay, sizeof(tx_delay));

Note that FQ packet scheduler limits might need some tweaking :

man tc-fq

PARAMETERS
   limit
       Hard  limit  on  the  real  queue  size. When this limit is
       reached, new packets are dropped. If the value is  lowered,
       packets  are  dropped so that the new limit is met. Default
       is 10000 packets.

   flow_limit
       Hard limit on the maximum  number  of  packets  queued  per
       flow.  Default value is 100.

Use of TCP_TX_DELAY option will increase number of skbs in FQ qdisc,
so packets would be dropped if any of the previous limit is hit.

Use of a jump label makes this support runtime-free, for hosts
never using the option.

Also note that TSQ (TCP Small Queues) limits are slightly changed
with this patch : we need to account that skbs artificially delayed
wont stop us providind more skbs to feed the pipe (netem uses
skb_orphan_partial() for this purpose, but FQ can not use this trick)

Because of that, using big delays might very well trigger
old bugs in TSO auto defer logic and/or sndbuf limited detection.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Get the ingress interface and increment ICMP counters based on that
instead of skb->dev when the the dev is a VRF device.

This is a follow up on the following message:
https://www.spinics.net/lists/netdev/msg560268.html

v2: Avoid changing skb->dev since it has unintended effect for local
    delivery (David Ahern).
Signed-off-by: NStephen Suryaputra <ssuryaextr@gmail.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The below patch fixes an incorrect zerocopy refcnt increment when
appending with MSG_MORE to an existing zerocopy udp skb.

  send(.., MSG_ZEROCOPY | MSG_MORE);	// refcnt 1
  send(.., MSG_ZEROCOPY | MSG_MORE);	// refcnt still 1 (bar frags)

But it missed that zerocopy need not be passed at the first send. The
right test whether the uarg is newly allocated and thus has extra
refcnt 1 is not !skb, but !skb_zcopy.

  send(.., MSG_MORE);			// <no uarg>
  send(.., MSG_ZEROCOPY);		// refcnt 1

Fixes: 100f6d8e ("net: correct zerocopy refcnt with udp MSG_MORE")
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add support for RTA_NH_ID attribute to allow a user to specify a
nexthop id to use with a route. fc_nh_id is added to fib6_config to
hold the value passed in the RTA_NH_ID attribute. If a nexthop id
is given, the gateway, device, encap and multipath attributes can
not be set.

Update ip6_route_del to check metric and protocol before nexthop
specs. If fc_nh_id is set, then it must match the id in the route
entry. Since IPv6 allows delete of a cached entry (an exception),
add ip6_del_cached_rt_nh to cycle through all of the fib6_nh in
a fib entry if it is using a nexthop.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use nexthop_for_each_fib6_nh to call fib6_nh_mtu_change for each
fib6_nh in a nexthop for rt6_mtu_change_route. For __ip6_rt_update_pmtu,
we need to find the nexthop that correlates to the device and gateway
in the rt6_info.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>