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Matteo Croce 258bbb1b0e icmp: don't fail on fragment reassembly time exceeded 
The ICMP implementation currently replies to an ICMP time exceeded message
(type 11) with an ICMP host unreachable message (type 3, code 1).

However, time exceeded messages can either represent "time to live exceeded
in transit" (code 0) or "fragment reassembly time exceeded" (code 1).

Unconditionally replying to "fragment reassembly time exceeded" with
host unreachable messages might cause unjustified connection resets
which are now easily triggered as UFO has been removed, because, in turn,
sending large buffers triggers IP fragmentation.

The issue can be easily reproduced by running a lot of UDP streams
which is likely to trigger IP fragmentation:

  # start netserver in the test namespace
  ip netns add test
  ip netns exec test netserver

  # create a VETH pair
  ip link add name veth0 type veth peer name veth0 netns test
  ip link set veth0 up
  ip -n test link set veth0 up

  for i in $(seq 20 29); do
      # assign addresses to both ends
      ip addr add dev veth0 192.168.$i.1/24
      ip -n test addr add dev veth0 192.168.$i.2/24

      # start the traffic
      netperf -L 192.168.$i.1 -H 192.168.$i.2 -t UDP_STREAM -l 0 &
  done

  # wait
  send_data: data send error: No route to host (errno 113)
  netperf: send_omni: send_data failed: No route to host

We need to differentiate instead: if fragment reassembly time exceeded
is reported, we need to silently drop the packet,
if time to live exceeded is reported, maintain the current behaviour.
In both cases increment the related error count "icmpInTimeExcds".

While at it, fix a typo in a comment, and convert the if statement
into a switch to mate it more readable.

Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 		2017-10-14 11:05:26 -07:00
..
netfilter netfilter: SYNPROXY: skip non-tcp packet in {ipv4, ipv6}_synproxy_hook 2017-10-09 13:08:39 +02:00
Kconfig
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Makefile tcp: ULP infrastructure 2017-06-15 12:12:40 -04:00
af_inet.c ipv4: Namespaceify tcp_fastopen_key knob 2017-10-01 17:55:54 -07:00
ah4.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2017-06-23 14:17:31 -04:00
arp.c neigh: increase queue_len_bytes to match wmem_default 2017-08-29 16:10:50 -07:00
cipso_ipv4.c Cipso: cipso_v4_optptr enter infinite loop 2017-08-01 15:31:23 -07:00
datagram.c
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devinet.c net: avoid a full fib lookup when rp_filter is disabled. 2017-09-21 15:15:22 -07:00
esp4.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-09-01 17:42:05 -07:00
esp4_offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-09-01 17:42:05 -07:00
fib_frontend.c net: avoid a full fib lookup when rp_filter is disabled. 2017-09-21 15:15:22 -07:00
fib_lookup.h ipv4: do metrics match when looking up and deleting a route 2017-08-23 20:37:10 -07:00
fib_notifier.c net: Add module reference to FIB notifiers 2017-09-01 20:33:42 -07:00
fib_rules.c net: fib_rules: Implement notification logic in core 2017-08-03 15:35:59 -07:00
fib_semantics.c net: ipv4: remove fib_info arg to fib_check_nh 2017-09-29 06:19:32 +01:00
fib_trie.c ipv4: do metrics match when looking up and deleting a route 2017-08-23 20:37:10 -07:00
fou.c gue: fix remcsum when GRO on and CHECKSUM_PARTIAL boundary is outer UDP 2017-08-01 16:09:14 -07:00
gre_demux.c
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gre_offload.c gso: fix payload length when gso_size is zero 2017-10-08 10:12:15 -07:00
icmp.c icmp: don't fail on fragment reassembly time exceeded 2017-10-14 11:05:26 -07:00
igmp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-21 17:06:42 -07:00
inet_connection_sock.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-09-23 10:16:53 -07:00
inet_diag.c inet_diag: allow protocols to provide additional data 2017-09-01 18:38:09 -07:00
inet_fragment.c Revert "net: use lib/percpu_counter API for fragmentation mem accounting" 2017-09-03 11:01:05 -07:00
inet_hashtables.c net: ipv4: add second dif to inet socket lookups 2017-08-07 11:39:21 -07:00
inet_timewait_sock.c net: convert sock.sk_refcnt from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
inetpeer.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-05 18:19:22 -07:00
ip_forward.c
…
ip_fragment.c Revert "net: fix percpu memory leaks" 2017-09-03 11:01:05 -07:00
ip_gre.c ip_gre: check packet length and mtu correctly in erspan tx 2017-10-07 23:17:21 +01:00
ip_input.c IPv4: early demux can return an error code 2017-10-01 03:55:47 +01:00
ip_options.c ip/options: explicitly provide net ns to __ip_options_echo() 2017-08-06 20:51:12 -07:00
ip_output.c udp: remove unreachable ufo branches 2017-08-22 14:27:18 -07:00
ip_sockglue.c net: ipv4: fix l3slave check for index returned in IP_PKTINFO 2017-09-15 14:27:51 -07:00
ip_tunnel.c ipv4: speedup ipv6 tunnels dismantle 2017-09-19 16:32:24 -07:00
ip_tunnel_core.c net: store port/representator id in metadata_dst 2017-06-25 11:42:01 -04:00
ip_vti.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-05 18:19:22 -07:00
ipcomp.c
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ipconfig.c networking: convert many more places to skb_put_zero() 2017-06-16 11:48:35 -04:00
ipip.c ipv4: speedup ipv6 tunnels dismantle 2017-09-19 16:32:24 -07:00
ipmr.c ipv4: ipmr: Don't forward packets already forwarded by hardware 2017-10-03 10:06:30 -07:00
netfilter.c
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ping.c net: convert sock.sk_refcnt from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
proc.c tcp: Revert "tcp: remove header prediction" 2017-08-30 11:20:09 -07:00
protocol.c
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raw.c net: ipv4: add second dif to multicast source filter 2017-08-07 11:39:22 -07:00
raw_diag.c net: ipv6: add second dif to raw socket lookups 2017-08-07 11:39:22 -07:00
route.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-09 20:11:09 -07:00
syncookies.c ip/options: explicitly provide net ns to __ip_options_echo() 2017-08-06 20:51:12 -07:00
sysctl_net_ipv4.c ipv4: Namespaceify tcp_fastopen_blackhole_timeout knob 2017-10-01 17:55:54 -07:00
tcp.c tcp: implement rb-tree based retransmit queue 2017-10-07 00:28:54 +01:00
tcp_bbr.c tcp_bbr: init pacing rate on first RTT sample 2017-07-15 14:43:29 -07:00
tcp_bic.c tcp: consolidate congestion control undo functions 2017-08-06 21:25:10 -07:00
tcp_cdg.c tcp: consolidate congestion control undo functions 2017-08-06 21:25:10 -07:00
tcp_cong.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-09-01 17:42:05 -07:00
tcp_cubic.c tcp: consolidate congestion control undo functions 2017-08-06 21:25:10 -07:00
tcp_dctcp.c
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tcp_diag.c tcp_diag: report TCP MD5 signing keys and addresses 2017-09-01 18:38:09 -07:00
tcp_fastopen.c net: add rb_to_skb() and other rb tree helpers 2017-10-07 00:28:53 +01:00
tcp_highspeed.c tcp: consolidate congestion control undo functions 2017-08-06 21:25:10 -07:00
tcp_htcp.c tcp: fix cwnd undo in Reno and HTCP congestion controls 2017-08-06 21:25:10 -07:00
tcp_hybla.c
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tcp_illinois.c tcp: consolidate congestion control undo functions 2017-08-06 21:25:10 -07:00
tcp_input.c tcp: implement rb-tree based retransmit queue 2017-10-07 00:28:54 +01:00
tcp_ipv4.c tcp: implement rb-tree based retransmit queue 2017-10-07 00:28:54 +01:00
tcp_lp.c
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tcp_metrics.c tcp: batch tcp_net_metrics_exit 2017-09-19 16:32:23 -07:00
tcp_minisocks.c tcp: new list for sent but unacked skbs for RACK recovery 2017-10-05 21:24:47 -07:00
tcp_nv.c tcp: consolidate congestion control undo functions 2017-08-06 21:25:10 -07:00
tcp_offload.c net: convert sock.sk_wmem_alloc from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
tcp_output.c tcp: implement rb-tree based retransmit queue 2017-10-07 00:28:54 +01:00
tcp_probe.c tcp: remove redundant argument from tcp_rcv_established() 2017-07-24 17:28:12 -07:00
tcp_rate.c tcp: export do_tcp_sendpages and tcp_rate_check_app_limited functions 2017-06-15 12:12:40 -04:00
tcp_recovery.c tcp: a small refactor of RACK loss detection 2017-10-05 21:24:47 -07:00
tcp_scalable.c tcp: consolidate congestion control undo functions 2017-08-06 21:25:10 -07:00
tcp_timer.c tcp: implement rb-tree based retransmit queue 2017-10-07 00:28:54 +01:00
tcp_ulp.c tcp: ulp: avoid module refcnt leak in tcp_set_ulp 2017-08-14 22:17:05 -07:00
tcp_vegas.c tcp: fix under-evaluated ssthresh in TCP Vegas 2017-09-29 06:07:00 +01:00
tcp_vegas.h
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tcp_veno.c tcp: consolidate congestion control undo functions 2017-08-06 21:25:10 -07:00
tcp_westwood.c tcp: Revert "tcp: remove CA_ACK_SLOWPATH" 2017-08-30 11:20:08 -07:00
tcp_yeah.c tcp: consolidate congestion control undo functions 2017-08-06 21:25:10 -07:00
tunnel4.c
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udp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-09 20:11:09 -07:00
udp_diag.c net: ipv6: add second dif to udp socket lookups 2017-08-07 11:39:22 -07:00
udp_impl.h
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udp_offload.c gso: fix payload length when gso_size is zero 2017-10-08 10:12:15 -07:00
udp_tunnel.c net: add infrastructure to un-offload UDP tunnel port 2017-07-24 13:52:59 -07:00
udplite.c
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xfrm4_input.c
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xfrm4_mode_beet.c networking: make skb_pull & friends return void pointers 2017-06-16 11:48:39 -04:00
xfrm4_mode_transport.c
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xfrm4_mode_tunnel.c
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xfrm4_output.c
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xfrm4_policy.c net: xfrm: support setting an output mark. 2017-08-11 07:03:00 +02:00
xfrm4_protocol.c
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xfrm4_state.c
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xfrm4_tunnel.c
…