linux/net/ipv6
Ignat Korchagin ed6ae5ca43 sit: allow encapsulated IPv6 traffic to be delivered locally
While experimenting with FOU encapsulation Amir noticed that encapsulated IPv6
traffic fails to be delivered, if the peer IP address is configured locally.

It can be easily verified by creating a sit interface like below:

$ sudo ip link add name fou_test type sit remote 127.0.0.1 encap fou encap-sport auto encap-dport 1111
$ sudo ip link set fou_test up

and sending some IPv4 and IPv6 traffic to it

$ ping -I fou_test -c 1 1.1.1.1
$ ping6 -I fou_test -c 1 fe80::d0b0:dfff:fe4c:fcbc

"tcpdump -i any udp dst port 1111" will confirm that only the first IPv4 ping
was encapsulated and attempted to be delivered.

This seems like a limitation: for example, in a cloud environment the "peer"
service may be arbitrarily scheduled on any server within the cluster, where all
nodes are trying to send encapsulated traffic. And the unlucky node will not be
able to. Moreover, delivering encapsulated IPv4 traffic locally is allowed.

But I may not have all the context about this restriction and this code predates
the observable git history.

Reported-by: Amir Razmjou <arazmjou@cloudflare.com>
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220107123842.211335-1-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-12 13:56:07 -08:00
..
ila
netfilter netfilter: flowtable: remove ipv4/ipv6 modules 2021-12-23 01:07:44 +01:00
addrconf_core.c ipv6: add net device refcount tracker to struct inet6_dev 2021-12-06 16:05:11 -08:00
addrconf.c ipv6: add net device refcount tracker to struct inet6_dev 2021-12-06 16:05:11 -08:00
addrlabel.c
af_inet6.c net: bpf: Handle return value of BPF_CGROUP_RUN_PROG_INET{4,6}_POST_BIND() 2022-01-06 17:08:35 -08:00
ah6.c ipv6: ah6: use swap() to make code cleaner 2021-11-18 12:00:15 +00:00
anycast.c
calipso.c
datagram.c
esp6_offload.c net: move gro definitions to include/net/gro.h 2021-11-16 13:16:54 +00:00
esp6.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2022-01-06 11:54:20 +00:00
exthdrs_core.c
exthdrs_offload.c
exthdrs.c ipv6: Remove duplicate statements 2021-11-14 12:20:44 +00:00
fib6_notifier.c
fib6_rules.c fib: rules: remove duplicated nla policies 2021-12-16 07:18:35 -08:00
fou6.c
icmp.c icmp: ICMPV6: Examine invoking packet for Segment Route Headers. 2022-01-04 12:17:35 +00:00
inet6_connection_sock.c
inet6_hashtables.c bpf: Add ingress_ifindex to bpf_sk_lookup 2021-11-10 16:29:58 -08:00
ioam6_iptunnel.c
ioam6.c ipv6: ioam: Support for Queue depth data field 2022-01-02 12:15:13 +00:00
ip6_checksum.c
ip6_fib.c net: Don't include filter.h from net/sock.h 2021-12-29 08:48:14 -08:00
ip6_flowlabel.c
ip6_gre.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-01-09 17:00:17 -08:00
ip6_icmp.c
ip6_input.c
ip6_offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-12-02 11:44:56 -08:00
ip6_offload.h
ip6_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-11-26 13:45:19 -08:00
ip6_tunnel.c ipv6: add net device refcount tracker to struct ip6_tnl 2021-12-06 16:05:11 -08:00
ip6_udp_tunnel.c
ip6_vti.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-12-30 12:12:12 -08:00
ip6mr.c fib: rules: remove duplicated nla policies 2021-12-16 07:18:35 -08:00
ipcomp6.c
ipv6_sockglue.c net-ipv6: changes to ->tclass (via IPV6_TCLASS) should sk_dst_reset() 2021-11-24 18:57:23 -08:00
Kconfig
Makefile
mcast_snoop.c
mcast.c
mip6.c
ndisc.c net: ndisc: introduce ndisc_evict_nocarrier sysctl parameter 2021-11-01 19:57:14 -07:00
netfilter.c
output_core.c
ping.c net: bpf: Handle return value of BPF_CGROUP_RUN_PROG_INET{4,6}_POST_BIND() 2022-01-06 17:08:35 -08:00
proc.c
protocol.c
raw.c ipv6: raw: check passed optlen before reading 2021-12-29 12:32:56 -08:00
reassembly.c
route.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-01-05 14:36:10 -08:00
rpl_iptunnel.c
rpl.c
seg6_hmac.c
seg6_iptunnel.c seg6: fix the iif in the IPv6 socket control block 2021-12-09 07:55:42 -08:00
seg6_local.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-01-05 14:36:10 -08:00
seg6.c icmp: ICMPV6: Examine invoking packet for Segment Route Headers. 2022-01-04 12:17:35 +00:00
sit.c sit: allow encapsulated IPv6 traffic to be delivered locally 2022-01-12 13:56:07 -08:00
syncookies.c net: align static siphash keys 2021-11-16 19:07:54 -08:00
sysctl_net_ipv6.c
tcp_ipv6.c net: bpf: Handle return value of BPF_CGROUP_RUN_PROG_INET{4,6}_POST_BIND() 2022-01-06 17:08:35 -08:00
tcpv6_offload.c net: move gro definitions to include/net/gro.h 2021-11-16 13:16:54 +00:00
tunnel6.c
udp_impl.h
udp_offload.c gro: remove rcu_read_lock/rcu_read_unlock from gro_receive handlers 2021-11-24 17:21:42 -08:00
udp.c Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2022-01-06 18:07:26 -08:00
udplite.c
xfrm6_input.c
xfrm6_output.c
xfrm6_policy.c xfrm: use net device refcount tracker helpers 2021-12-09 11:51:45 -08:00
xfrm6_protocol.c
xfrm6_state.c
xfrm6_tunnel.c