linux/net/ipv4
Herbert Xu 23ca0c989e ipip: Fix handling of DF packets when pmtudisc is OFF
RFC 2003 requires the outer header to have DF set if DF is set
on the inner header, even when PMTU discovery is off for the
tunnel.  Our implementation does exactly that.

For this to work properly the IPIP gateway also needs to engate
in PMTU when the inner DF bit is set.  As otherwise the original
host would not be able to carry out its PMTU successfully since
part of the path is only visible to the gateway.

Unfortunately when the tunnel PMTU discovery setting is off, we
do not collect the necessary soft state, resulting in blackholes
when the original host tries to perform PMTU discovery.

This problem is not reproducible on the IPIP gateway itself as
the inner packet usually has skb->local_df set.  This is not
correctly cleared (an unrelated bug) when the packet passes
through the tunnel, which allows fragmentation to occur.  For
hosts behind the IPIP gateway it is readily visible with a simple
ping.

This patch fixes the problem by performing PMTU discovery for
all packets with the inner DF bit set, regardless of the PMTU
discovery setting on the tunnel itself.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-06 20:33:40 -08:00
..
netfilter netfilter: nf_nat: fix NAT issue in 2.6.30.4+ 2009-11-06 00:43:42 -08:00
af_inet.c net: Use sk_mark for routing lookup in more places 2009-10-01 15:16:49 -07:00
ah4.c net: constify struct net_protocol 2009-09-14 17:03:01 -07:00
arp.c net: make neigh_ops constant 2009-09-01 17:40:57 -07:00
cipso_ipv4.c netlabel: Label incoming TCP connections correctly in SELinux 2009-03-28 15:01:36 +11:00
datagram.c mib: add net to IP_INC_STATS_BH 2008-07-16 20:20:11 -07:00
devinet.c ipv4: arp_notify address list bug 2009-10-07 03:18:17 -07:00
esp4.c net: constify struct net_protocol 2009-09-14 17:03:01 -07:00
fib_frontend.c net: Fix RPF to work with policy routing 2009-10-29 22:49:12 -07:00
fib_hash.c ipv4: cleanup - remove two unused parameters from fib_semantic_match(). 2009-05-18 15:16:37 -07:00
fib_lookup.h ipv4: cleanup - remove two unused parameters from fib_semantic_match(). 2009-05-18 15:16:37 -07:00
fib_rules.c net: Remove unused parameter from fill method in fib_rules_ops. 2009-05-20 17:26:23 -07:00
fib_semantics.c ipv4: cleanup - remove two unused parameters from fib_semantic_match(). 2009-05-18 15:16:37 -07:00
fib_trie.c fib_trie: resize rework 2009-08-28 23:57:15 -07:00
icmp.c net: constify struct net_protocol 2009-09-14 17:03:01 -07:00
igmp.c bonding: remap muticast addresses without using dev_close() and dev_open() 2009-09-15 02:37:40 -07:00
inet_connection_sock.c tcp: reduce SYN-ACK retrans for TCP_DEFER_ACCEPT 2009-10-19 19:19:03 -07:00
inet_diag.c net: correct off-by-one write allocations reports 2009-06-18 00:29:12 -07:00
inet_fragment.c inet fragments: fix sparse warning: context imbalance 2009-02-26 23:13:35 -08:00
inet_hashtables.c net: move bsockets outside of read only beginning of struct inet_hashinfo 2009-02-01 12:31:33 -08:00
inet_lro.c include/net net/ - csum_partial - remove unnecessary casts 2008-11-19 15:44:53 -08:00
inet_timewait_sock.c tcp: fix premature termination of FIN_WAIT2 time-wait sockets 2009-08-29 00:00:35 -07:00
inetpeer.c net: clean up net/ipv4/ah4.c esp4.c fib_semantics.c inet_connection_sock.c inetpeer.c ip_output.c 2008-11-03 00:23:42 -08:00
ip_forward.c net: skb->dst accessors 2009-06-03 02:51:04 -07:00
ip_fragment.c ipv4: Use frag list abstraction interfaces. 2009-06-09 00:19:37 -07:00
ip_gre.c gre: Fix dev_addr clobbering for gretap 2009-10-30 12:28:07 -07:00
ip_input.c net: constify struct net_protocol 2009-09-14 17:03:01 -07:00
ip_options.c net: skb->dst accessors 2009-06-03 02:51:04 -07:00
ip_output.c net: Use sk_mark for routing lookup in more places 2009-10-01 15:16:49 -07:00
ip_sockglue.c net: Fix IP_MULTICAST_IF 2009-10-19 21:34:20 -07:00
ipcomp.c net: constify struct net_protocol 2009-09-14 17:03:01 -07:00
ipconfig.c ipv4: teach ipconfig about the MTU option in DHCP 2009-05-19 15:36:17 -07:00
ipip.c ipip: Fix handling of DF packets when pmtudisc is OFF 2009-11-06 20:33:40 -08:00
ipmr.c net: Make setsockopt() optlen be unsigned. 2009-09-30 16:12:20 -07:00
Kconfig ipv4: update ARPD help text 2009-06-13 23:36:32 -07:00
Makefile IPVS: Move IPVS to net/netfilter/ipvs 2008-10-07 08:38:24 +11:00
netfilter.c net: skb->dst accessors 2009-06-03 02:51:04 -07:00
proc.c snmp: add missing counters for RFC 4293 2009-04-27 02:45:02 -07:00
protocol.c net: constify struct net_protocol 2009-09-14 17:03:01 -07:00
raw.c AF_RAW: Augment raw_send_hdrinc to expand skb to fit iphdr->ihl (v2) 2009-10-29 01:09:58 -07:00
route.c net: Fix RPF to work with policy routing 2009-10-29 22:49:12 -07:00
syncookies.c percpu: clean up percpu variable definitions 2009-06-24 15:13:48 +09:00
sysctl_net_ipv4.c sysctl: remove "struct file *" argument of ->proc_handler 2009-09-24 07:21:04 -07:00
tcp_bic.c tcp: add helper for AI algorithm 2009-03-02 03:00:15 -08:00
tcp_cong.c Networking: use CAP_NET_ADMIN when deciding to call request_module 2009-08-14 11:18:34 +10:00
tcp_cubic.c tcp: add helper for AI algorithm 2009-03-02 03:00:15 -08:00
tcp_diag.c net: inet_diag_handler structs can be const 2008-11-19 15:43:27 -08:00
tcp_highspeed.c
tcp_htcp.c htcp: merge icsk_ca_state compare 2009-03-02 03:00:14 -08:00
tcp_hybla.c tcp: Fix tcp_hybla zero congestion window growth with small rho and large cwnd. 2008-10-07 15:58:17 -07:00
tcp_illinois.c
tcp_input.c tcp: fix ssthresh u16 leftover 2009-09-15 01:30:10 -07:00
tcp_ipv4.c tcp: fix ssthresh u16 leftover 2009-09-15 01:30:10 -07:00
tcp_lp.c
tcp_minisocks.c tcp: accept socket after TCP_DEFER_ACCEPT period 2009-10-19 19:19:01 -07:00
tcp_output.c IPv4 TCP fails to send window scale option when window scale is zero 2009-10-01 15:14:51 -07:00
tcp_probe.c tcp: '< 0' test on unsigned 2009-03-13 16:05:14 -07:00
tcp_scalable.c tcp: add helper for AI algorithm 2009-03-02 03:00:15 -08:00
tcp_timer.c Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value. 2009-09-01 02:45:47 -07:00
tcp_vegas.c tcp: tcp_vegas ssthresh bugfix 2009-05-25 22:44:59 -07:00
tcp_vegas.h
tcp_veno.c tcp: add helper for AI algorithm 2009-03-02 03:00:15 -08:00
tcp_westwood.c
tcp_yeah.c tcp: add helper for AI algorithm 2009-03-02 03:00:15 -08:00
tcp.c net: use WARN() for the WARN_ON in commit b6b39e8f3f 2009-10-22 21:37:56 -07:00
tunnel4.c net: constify struct net_protocol 2009-09-14 17:03:01 -07:00
udp_impl.h net: Make setsockopt() optlen be unsigned. 2009-09-30 16:12:20 -07:00
udp.c net: fix sk_forward_alloc corruption 2009-10-30 12:25:12 -07:00
udplite.c net: constify struct net_protocol 2009-09-14 17:03:01 -07:00
xfrm4_input.c net: skb->dst accessors 2009-06-03 02:51:04 -07:00
xfrm4_mode_beet.c ipsec: Interfamily IPSec BEET 2008-08-06 02:39:30 -07:00
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c net: skb->dst accessors 2009-06-03 02:51:04 -07:00
xfrm4_output.c net: skb->dst accessors 2009-06-03 02:51:04 -07:00
xfrm4_policy.c xfrm4: fix build when SYSCTLs are disabled 2009-08-04 20:18:33 -07:00
xfrm4_state.c xfrm: remove useless forward declarations 2008-11-25 01:05:54 -08:00
xfrm4_tunnel.c