The current definitions of constants for PROBE, currently defined only
in the net-next kernel branch, are inconsistent, with
some beginning with ICMP and others with simply EXT. This patch
attempts to standardize the naming conventions of the constants for
PROBE before their release into a stable Kernel, and to update the
relevant definitions in net/ipv4/icmp.c.

Similarly, the definitions for the code field (previously
ICMP_EXT_MAL_QUERY, etc) use the same prefixes as the type field. This
patch adds _CODE_ to the prefix to clarify the distinction of these
constants.
Signed-off-by: NAndreas Roeseler <andreas.a.roeseler@gmail.com>
Acked-by: NDavid Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20210427153635.2591-1-andreas.a.roeseler@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

The compat layer needs to parse untrusted input (the ruleset)
to translate it to a 64bit compatible format.

We had a number of bugs in this department in the past, so allow users
to turn this feature off.

Add CONFIG_NETFILTER_XTABLES_COMPAT kconfig knob and make it default to y
to keep existing behaviour.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Same change as previous patch.  Only difference:
no need to handle NULL template_ops parameter, the only caller
(arptable_filter) always passes non-NULL argument.

This removes all remaining accesses to net->ipv4.arptable_filter.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

iptable_x modules rely on 'struct net' to contain a pointer to the
table that should be evaluated.

In order to remove these pointers from struct net, pass them via
the 'priv' pointer in a similar fashion as nf_tables passes the
rule data.

To do that, duplicate the nf_hook_info array passed in from the
iptable_x modules, update the ops->priv pointers of the copy to
refer to the table and then change the hookfn implementations to
just pass the 'priv' argument to the traverser.

After this patch, the xt_table pointers can already be removed
from struct net.

However, changes to struct net result in re-compile of the entire
network stack, so do the removal after arptables and ip6tables
have been converted as well.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This changes how ip(6)table nat passes the ruleset/table to the
evaluation loop.

At the moment, it will fetch the table from struct net.

This change stores the table in the hook_ops 'priv' argument
instead.

This requires to duplicate the hook_ops for each netns, so
they can store the (per-net) xt_table structure.

The dupliated nat hook_ops get stored in net_generic data area.
They are free'd in the namespace exit path.

This is a pre-requisite to remove the xt_table/ruleset pointers
from struct net.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

No need for these.
There is only one caller, the xtables core, when the table is registered
for the first time with a particular network namespace.

After ->table_init() call, the table is linked into the tables[af] list,
so next call to that function will skip the ->table_init().
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

and again, this time for arptables.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

xtables stores the xt_table structs in the struct net.  This isn't
needed anymore, the structures could be passed via the netfilter hook
'private' pointer to the hook functions, which would allow us to remove
those pointers from struct net.

As a first step, reduce the number of accesses to the
net->ipv4.ip6table_{raw,filter,...} pointers.
This allows the tables to get unregistered by name instead of having to
pass the raw address.

The xt_table structure cane looked up by name+address family instead.

This patch is useless as-is (the backends still have the raw pointer
address), but it lowers the bar to remove those.

It also allows to put the 'was table registered in the first place' check
into ip_tables.c rather than have it in each table sub module.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Its the same function as ipt_unregister_table_exit.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

When I changed defrag hooks to no longer get registered by default I
intentionally made it so that registration can only be un-done by unloading
the nf_defrag_ipv4/6 module.

In hindsight this was too conservative; there is no reason to keep defrag
on while there is no feature dependency anymore.

Moreover, this won't work if user isn't allowed to remove nf_defrag module.

This adds the disable() functions for both ipv4 and ipv6 and calls them
from conntrack, TPROXY and the xtables socket module.

ipvs isn't converted here, it will behave as before this patch and
will need module removal.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Currently, a multi-part nexthop dump is restarted based on the number of
nexthops that have been dumped so far. This can result in a lot of
nexthops not being dumped when nexthops are simultaneously deleted:

 # ip nexthop | wc -l
 65536
 # ip nexthop flush
 Dump was interrupted and may be inconsistent.
 Flushed 36040 nexthops
 # ip nexthop | wc -l
 29496

Instead, restart the dump based on the nexthop identifier (fixed number)
of the last successfully dumped nexthop:

 # ip nexthop | wc -l
 65536
 # ip nexthop flush
 Dump was interrupted and may be inconsistent.
 Flushed 65536 nexthops
 # ip nexthop | wc -l
 0
Reported-by: NMaksym Yaremchuk <maksymy@nvidia.com>
Tested-by: NMaksym Yaremchuk <maksymy@nvidia.com>
Signed-off-by: NIdo Schimmel <idosch@nvidia.com>
Reviewed-by: NPetr Machata <petrm@nvidia.com>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Netfilter tries to reroute mangled packets as a different route might
need to be used following the mangling. When this happens, netfilter
does not populate the IP protocol, the source port and the destination
port in the flow key. Therefore, FIB rules that match on these fields
are ignored and packets can be misrouted.

Solve this by dissecting the outer flow and populating the flow key
before rerouting the packet. Note that flow dissection only happens when
FIB rules that match on these fields are installed, so in the common
case there should not be a penalty.
Reported-by: NMichal Soltys <msoltyspl@yandex.pl>
Signed-off-by: NIdo Schimmel <idosch@nvidia.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Currently, tcp_allowed_congestion_control is global and writable;
writing to it in any net namespace will leak into all other net
namespaces.

tcp_available_congestion_control and tcp_allowed_congestion_control are
the only sysctls in ipv4_net_table (the per-netns sysctl table) with a
NULL data pointer; their handlers (proc_tcp_available_congestion_control
and proc_allowed_congestion_control) have no other way of referencing a
struct net. Thus, they operate globally.

Because ipv4_net_table does not use designated initializers, there is no
easy way to fix up this one "bad" table entry. However, the data pointer
updating logic shouldn't be applied to NULL pointers anyway, so we
instead force these entries to be read-only.

These sysctls used to exist in ipv4_table (init-net only), but they were
moved to the per-net ipv4_net_table, presumably without realizing that
tcp_allowed_congestion_control was writable and thus introduced a leak.

Because the intent of that commit was only to know (i.e. read) "which
congestion algorithms are available or allowed", this read-only solution
should be sufficient.

The logic added in recent commit
31c4d2f1: ("net: Ensure net namespace isolation of sysctls")
does not and cannot check for NULL data pointers, because
other table entries (e.g. /proc/sys/net/netfilter/nf_log/) have
.data=NULL but use other methods (.extra2) to access the struct net.

Fixes: 9cb8e048 ("net/ipv4/sysctl: show tcp_{allowed, available}_congestion_control in non-initial netns")
Signed-off-by: NJonathon Reinhart <jonathon.reinhart@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current icmp_rcv function drops all unknown ICMP types, including
ICMP_EXT_ECHOREPLY (type 43). In order to parse Extended Echo Reply messages, we have
to pass these packets to the ping_rcv function, which does not do any
other filtering and passes the packet to the designated socket.

Pass incoming RFC 8335 ICMP Extended Echo Reply packets to the ping_rcv
handler instead of discarding the packet.
Signed-off-by: NAndreas Roeseler <andreas.a.roeseler@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

xt_compat_match/target_from_user doesn't check that zeroing the area
to start of next rule won't write past end of allocated ruleset blob.

Remove this code and zero the entire blob beforehand.

Reported-by: syzbot+cfc0247ac173f597aaaa@syzkaller.appspotmail.com
Reported-by: NAndy Nguyen <theflow@google.com>
Fixes: 9fa492cd ("[NETFILTER]: x_tables: simplify compat API")
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Using sk_psock() to retrieve psock pointer from sock requires
RCU read lock, but we already get psock pointer before calling
->psock_update_sk_prot() in both cases, so we can just pass it
without bothering sk_psock().

Fixes: 8a59f9d1 ("sock: Introduce sk->sk_prot->psock_update_sk_prot()")
Reported-by: syzbot+320a3bc8d80f478c37e4@syzkaller.appspotmail.com
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Tested-by: syzbot+320a3bc8d80f478c37e4@syzkaller.appspotmail.com
Reviewed-by: NJakub Sitnicki <jakub@cloudflare.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210407032111.33398-1-xiyou.wangcong@gmail.com

Same problem that also existed in iptables/ip(6)tables, when
arptable_filter is removed there is no longer a wait period before the
table/ruleset is free'd.

Unregister the hook in pre_exit, then remove the table in the exit
function.
This used to work correctly because the old nf_hook_unregister API
did unconditional synchronize_net.

The per-net hook unregister function uses call_rcu instead.

Fixes: b9e69e12 ("netfilter: xtables: don't hook tables by default")
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This reverts commit e880f8b3.

1) Patch has not been properly tested, and is wrong [1]
2) Patch submission did not include TCP maintainer (this is me)

[1]
divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8426 Comm: syz-executor478 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__tcp_select_window+0x56d/0xad0 net/ipv4/tcp_output.c:3015
Code: 44 89 ff e8 d5 cd f0 f9 45 39 e7 0f 8d 20 ff ff ff e8 f7 c7 f0 f9 44 89 e3 e9 13 ff ff ff e8 ea c7 f0 f9 44 89 e0 44 89 e3 99 <f7> 7c 24 04 29 d3 e9 fc fe ff ff e8 d3 c7 f0 f9 41 f7 dc bf 1f 00
RSP: 0018:ffffc9000184fac0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff87832e76 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff87832e14 R11: 0000000000000000 R12: 0000000000000000
R13: 1ffff92000309f5c R14: 0000000000000000 R15: 0000000000000000
FS:  00000000023eb300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc2b5f426c0 CR3: 000000001c5cf000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tcp_select_window net/ipv4/tcp_output.c:264 [inline]
 __tcp_transmit_skb+0xa82/0x38f0 net/ipv4/tcp_output.c:1351
 tcp_transmit_skb net/ipv4/tcp_output.c:1423 [inline]
 tcp_send_active_reset+0x475/0x8e0 net/ipv4/tcp_output.c:3449
 tcp_disconnect+0x15a9/0x1e60 net/ipv4/tcp.c:2955
 inet_shutdown+0x260/0x430 net/ipv4/af_inet.c:905
 __sys_shutdown_sock net/socket.c:2189 [inline]
 __sys_shutdown_sock net/socket.c:2183 [inline]
 __sys_shutdown+0xf1/0x1b0 net/socket.c:2201
 __do_sys_shutdown net/socket.c:2209 [inline]
 __se_sys_shutdown net/socket.c:2207 [inline]
 __x64_sys_shutdown+0x50/0x70 net/socket.c:2207
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: e880f8b3 ("tcp: Reset tcp connections in SYN-SENT state")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Cc: Manoj Basapathi <manojbm@codeaurora.org>
Cc: Sauvik Saha <ssaha@codeaurora.org>
Link: https://lore.kernel.org/r/20210409170237.274904-1-eric.dumazet@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

Setting iftoken can fail for several different reasons but there
and there was no report to user as to the cause. Add netlink
extended errors to the processing of the request.

This requires adding additional argument through rtnl_af_ops
set_link_af callback.
Reported-by: NHongren Zheng <li@zenithal.me>
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Userspace sends tcp connection (sock) destroy on network switch
i.e switching the default network of the device between multiple
networks(Cellular/Wifi/Ethernet).

Kernel though doesn't send reset for the connections in SYN-SENT state
and these connections continue to remain.
Even as per RFC 793, there is no hard rule to not send RST on ABORT in
this state.

Modify tcp_abort and tcp_disconnect behavior to send RST for connections
in syn-sent state to avoid lingering connections on network switch.
Signed-off-by: NManoj Basapathi <manojbm@codeaurora.org>
Signed-off-by: NSauvik Saha <ssaha@codeaurora.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These comments in udp_bpf_update_proto() are copied from the
original TCP code and apparently do not apply to UDP. Just
remove them.
Reported-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210403052715.13854-1-xiyou.wangcong@gmail.com

This allows followup patch to remove the defrag_ipv4 member from struct
net.  It also allows to auto-remove the hooks later on by adding a
_disable() function.  This will be done later in a follow patch series.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

The MPTCP reset option allows to carry a mptcp-specific error code that
provides more information on the nature of a connection reset.

Reset option data received gets stored in the subflow context so it can
be sent to userspace via the 'subflow closed' netlink event.

When a subflow is closed, the desired error code that should be sent to
the peer is also placed in the subflow context structure.

If a reset is sent before subflow establishment could complete, e.g. on
HMAC failure during an MP_JOIN operation, the mptcp skb extension is
used to store the reset information.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Support for UDP_GRO was added in the past but the implementation for
getsockopt was missed which did lead to an error when we tried to
retrieve the setting for UDP_GRO. This patch adds the missing switch
case for UDP_GRO

Fixes: e20cf8d3 ("udp: implement GRO for plain UDP sockets.")
Signed-off-by: NNorman Maurer <norman_maurer@apple.com>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We have to implement udp_bpf_recvmsg() to replace the ->recvmsg()
to retrieve skmsg from ingress_msg.
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-14-xiyou.wangcong@gmail.com

Although these two functions are only used by TCP, they are not
specific to TCP at all, both operate on skmsg and ingress_msg,
so fit in net/core/skmsg.c very well.

And we will need them for non-TCP, so rename and move them to
skmsg.c and export them to modules.
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210331023237.41094-13-xiyou.wangcong@gmail.com

This is similar to tcp_read_sock(), except we do not need
to worry about connections, we just need to retrieve skb
from UDP receive queue.

Note, the return value of ->read_sock() is unused in
sk_psock_verdict_data_ready(), and UDP still does not
support splice() due to lack of ->splice_read(), so users
can not reach udp_read_sock() directly.
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-12-xiyou.wangcong@gmail.com

Currently sockmap calls into each protocol to update the struct
proto and replace it. This certainly won't work when the protocol
is implemented as a module, for example, AF_UNIX.

Introduce a new ops sk->sk_prot->psock_update_sk_prot(), so each
protocol can implement its own way to replace the struct proto.
This also helps get rid of symbol dependencies on CONFIG_INET.
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210331023237.41094-11-xiyou.wangcong@gmail.com

Currently we rely on lock_sock to protect ingress_msg,
it is too big for this, we can actually just use a spinlock
to protect this list like protecting other skb queues.

__tcp_bpf_recvmsg() is still special because of peeking,
it still has to use lock_sock.
Signed-off-by: NCong Wang <cong.wang@bytedance.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NJakub Sitnicki <jakub@cloudflare.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-3-xiyou.wangcong@gmail.com

tcp_comp_sack_nr max value was already 255.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This sysctl is a bool, can use less storage.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make room for better packing of netns_ipv4
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reduce footprint of sysctls.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reduce footprint of sysctls.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sysctl_icmp_echo_enable_probe is an u8.

ipv4_net_table entry should use
 .maxlen       = sizeof(u8).
 .proc_handler = proc_dou8vec_minmax,

Fixes: f1b8fa9f ("net: add sysctl for enabling RFC 8335 PROBE messages")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Andreas Roeseler <andreas.a.roeseler@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently the UDP protocol delivers GSO_FRAGLIST packets to
the sockets without the expected segmentation.

This change addresses the issue introducing and maintaining
a couple of new fields to explicitly accept SKB_GSO_UDP_L4
or GSO_FRAGLIST packets. Additionally updates  udp_unexpected_gso()
accordingly.

UDP sockets enabling UDP_GRO stil keep accept_udp_fraglist
zeroed.

v1 -> v2:
 - use 2 bits instead of a whole GSO bitmask (Willem)

Fixes: 9fd1ff5d ("udp: Support UDP fraglist GRO/GSO.")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After the previous patch, the stack can do L4 UDP aggregation
on top of a UDP tunnel.

In such scenario, udp{4,6}_gro_complete will be called twice. This function
will enter its is_flist branch immediately, even though that is only
correct on the second call, as GSO_FRAGLIST is only relevant for the
inner packet.

Instead, we need to try first UDP tunnel-based aggregation, if the GRO
packet requires that.

This patch changes udp{4,6}_gro_complete to skip the frag list processing
when while encap_mark == 1, identifying processing of the outer tunnel
header.
Additionally, clears the field in udp_gro_complete() so that we can enter
the frag list path on the next round, for the inner header.

v1 -> v2:
 - hopefully clarified the commit message
Reviewed-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If NETIF_F_GRO_FRAGLIST or NETIF_F_GRO_UDP_FWD are enabled, and there
are UDP tunnels available in the system, udp_gro_receive() could end-up
doing L4 aggregation (either SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST) at
the outer UDP tunnel level for packets effectively carrying and UDP
tunnel header.

That could cause inner protocol corruption. If e.g. the relevant
packets carry a vxlan header, different vxlan ids will be ignored/
aggregated to the same GSO packet. Inner headers will be ignored, too,
so that e.g. TCP over vxlan push packets will be held in the GRO
engine till the next flush, etc.

Just skip the SKB_GSO_UDP_L4 and SKB_GSO_FRAGLIST code path if the
current packet could land in a UDP tunnel, and let udp_gro_receive()
do GRO via udp_sk(sk)->gro_receive.

The check implemented in this patch is broader than what is strictly
needed, as the existing UDP tunnel could be e.g. configured on top of
a different device: we could end-up skipping GRO at-all for some packets.

Anyhow, that is a very thin corner case and covering it will add quite
a bit of complexity.

v1 -> v2:
 - hopefully clarify the commit message

Fixes: 9fd1ff5d ("udp: Support UDP fraglist GRO/GSO.")
Fixes: 36707061 ("udp: allow forwarding of plain (non-fraglisted) UDP GRO packets")
Reviewed-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When UDP packets generated locally by a socket with UDP_SEGMENT
traverse the following path:

UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) ->
	UDP tunnel (rx) -> UDP socket (no UDP_GRO)

ip_summed will be set to CHECKSUM_PARTIAL at creation time and
such checksum mode will be preserved in the above path up to the
UDP tunnel receive code where we have:

 __iptunnel_pull_header() -> skb_pull_rcsum() ->
skb_postpull_rcsum() -> __skb_postpull_rcsum()

The latter will convert the skb to CHECKSUM_NONE.

The UDP GSO packet will be later segmented as part of the rx socket
receive operation, and will present a CHECKSUM_NONE after segmentation.

Additionally the segmented packets UDP CB still refers to the original
GSO packet len. Overall that causes unexpected/wrong csum validation
errors later in the UDP receive path.

We could possibly address the issue with some additional checks and
csum mangling in the UDP tunnel code. Since the issue affects only
this UDP receive slow path, let's set a suitable csum status there.

Note that SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets lacking an UDP
encapsulation present a valid checksum when landing to udp_queue_rcv_skb(),
as the UDP checksum has been validated by the GRO engine.

v2 -> v3:
 - even more verbose commit message and comments

v1 -> v2:
 - restrict the csum update to the packets strictly needing them
 - hopefully clarify the commit message and code comments
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Reviewed-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

similar to previous change: nf_log_syslog now covers ARP logging
as well, the old nf_log_arp module is removed.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>