linux/net/ipv4
Florian Westphal f1673381b1 syncookies: split cookie_check_timestamp() into two functions
The function cookie_check_timestamp(), both called from IPv4/6 context,
is being used to decode the echoed timestamp from the SYN/ACK into TCP
options used for follow-up communication with the peer.

We can remove ECN handling from that function, split it into a separate
one, and simply rename the original function into cookie_decode_options().
cookie_decode_options() just fills in tcp_option struct based on the
echoed timestamp received from the peer. Anything that fails in this
function will actually discard the request socket.

While this is the natural place for decoding options such as ECN which
commit 172d69e63c ("syncookies: add support for ECN") added, we argue
that in particular for ECN handling, it can be checked at a later point
in time as the request sock would actually not need to be dropped from
this, but just ECN support turned off.

Therefore, we split this functionality into cookie_ecn_ok(), which tells
us if the timestamp indicates ECN support AND the tcp_ecn sysctl is enabled.

This prepares for per-route ECN support: just looking at the tcp_ecn sysctl
won't be enough anymore at that point; if the timestamp indicates ECN
and sysctl tcp_ecn == 0, we will also need to check the ECN dst metric.

This would mean adding a route lookup to cookie_check_timestamp(), which
we definitely want to avoid. As we already do a route lookup at a later
point in cookie_{v4,v6}_check(), we can simply make use of that as well
for the new cookie_ecn_ok() function w/o any additional cost.

Joint work with Daniel Borkmann.

Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-11-04 16:06:09 -05:00
..
netfilter netfilter: nf_reject_ipv4: split nf_send_reset() in smaller functions 2014-10-31 12:49:05 +01:00
af_inet.c net: gso: use feature flag argument in all protocol gso handlers 2014-10-20 12:38:12 -04:00
ah4.c ipsec: Remove obsolete MAX_AH_AUTH_LEN 2014-09-18 10:54:36 +02:00
arp.c arp: Do not perturb drop profiles with ignored ARP packets 2014-09-28 17:30:35 -04:00
cipso_ipv4.c cipso: remove NULL assignment on static 2014-11-04 15:09:52 -05:00
datagram.c net: Save TX flow hash in sock and set in skbuf on xmit 2014-07-07 21:14:21 -07:00
devinet.c ipv4: fail early when creating netdev named all or default 2014-07-29 11:43:50 -07:00
esp4.c esp4: Use the IPsec protocol multiplexer API 2014-02-25 07:04:17 +01:00
fib_frontend.c ipv4: Restore accept_local behaviour in fib_validate_source() 2014-08-22 12:23:10 -07:00
fib_lookup.h ipv4: make fib_detect_death static 2013-12-28 17:01:46 -05:00
fib_rules.c inet: fix NULL pointer Oops in fib(6)_rule_suppress 2013-12-10 17:54:23 -05:00
fib_semantics.c ipv4: fix nexthop attlen check in fib_nh_match 2014-10-14 15:59:37 -04:00
fib_trie.c list: fix order of arguments for hlist_add_after(_rcu) 2014-08-06 18:01:24 -07:00
fou.c ipv4: fix a potential use after free in fou.c 2014-10-17 23:45:26 -04:00
geneve.c ipv4: minor spelling fixes 2014-10-30 16:14:43 -04:00
gre_demux.c net: Fix GRE RX to use skb_transport_header for GRE header offset 2014-09-08 15:23:05 -07:00
gre_offload.c gre: Use inner mac length when computing tunnel length 2014-10-30 19:51:56 -04:00
icmp.c icmp: add a global rate limitation 2014-09-23 12:47:38 -04:00
igmp.c igmp: remove camel case definitions 2014-11-04 15:13:18 -05:00
inet_connection_sock.c ipv4: make ip_local_reserved_ports per netns 2014-05-14 15:31:45 -04:00
inet_diag.c inet_diag: fix inet_diag_dump_icsk() to use correct state for timewait sockets 2014-01-13 22:35:46 -08:00
inet_fragment.c inet: frags: remove the WARN_ON from inet_evict_bucket 2014-10-29 15:21:30 -04:00
inet_hashtables.c net: use reciprocal_scale() helper 2014-08-23 12:21:21 -07:00
inet_lro.c lro: remove dead code 2013-12-29 16:34:25 -05:00
inet_timewait_sock.c
inetpeer.c inet: remove dead inetpeer sequence code 2014-09-08 16:42:42 -07:00
ip_forward.c net: rename local_df to ignore_df 2014-05-12 14:03:41 -04:00
ip_fragment.c inet: frags: remove inline on static in c file 2014-11-04 15:13:18 -05:00
ip_gre.c net: better IFF_XMIT_DST_RELEASE support 2014-10-07 13:22:11 -04:00
ip_input.c net: Fix memory leak if TPROXY used with TCP early demux 2014-01-27 16:22:11 -08:00
ip_options.c ipv4: rename ip_options_echo to __ip_options_echo() 2014-09-28 16:35:42 -04:00
ip_output.c net: make skb_gso_segment error handling more robust 2014-10-20 12:38:13 -04:00
ip_sockglue.c ipv4: rcu cleanup in ip_ra_control() 2014-09-09 20:10:44 -07:00
ip_tunnel_core.c ipv4: fix a potential use after free in ip_tunnel_core.c 2014-10-17 23:45:26 -04:00
ip_tunnel.c ip_tunnel: Add GUE support 2014-10-03 16:53:33 -07:00
ip_vti.c net: better IFF_XMIT_DST_RELEASE support 2014-10-07 13:22:11 -04:00
ipcomp.c ipcomp4: Use the IPsec protocol multiplexer API 2014-02-25 07:04:17 +01:00
ipconfig.c ipv4: remove 0/NULL assignment on static 2014-11-04 15:09:52 -05:00
ipip.c net: better IFF_XMIT_DST_RELEASE support 2014-10-07 13:22:11 -04:00
ipmr.c net: set name_assign_type in alloc_netdev() 2014-07-15 16:12:48 -07:00
Kconfig openvswitch: fix a compilation error when CONFIG_INET is not setW! 2014-10-07 00:10:49 -04:00
Makefile net: Add Geneve tunneling protocol driver 2014-10-06 00:32:20 -04:00
netfilter.c netfilter: remove double colon 2014-02-19 11:41:25 +01:00
ping.c net/ipv4: bind ip_nonlocal_bind to current netns 2014-09-09 11:27:09 -07:00
proc.c ipv4: use seq_puts instead of seq_printf where possible 2014-11-04 15:09:52 -05:00
protocol.c net: Export inet_offloads and inet6_offloads 2014-09-19 17:15:31 -04:00
raw.c ipv4: Make IP_MULTICAST_ALL and IP_MSFILTER work on raw sockets 2014-07-23 15:13:26 -07:00
route.c ipv4: Do not cache routing failures due to disabled forwarding. 2014-10-30 19:20:40 -04:00
syncookies.c syncookies: split cookie_check_timestamp() into two functions 2014-11-04 16:06:09 -05:00
sysctl_net_ipv4.c tcp: allow for bigger reordering level 2014-10-29 15:05:15 -04:00
tcp_bic.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_cong.c tcp: spelling s/plugable/pluggable 2014-11-04 15:09:52 -05:00
tcp_cubic.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_dctcp.c net: tcp: add DCTCP congestion control algorithm 2014-09-29 00:13:10 -04:00
tcp_diag.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_fastopen.c tcp: remove unnecessary assignment. 2014-09-29 12:31:12 -04:00
tcp_highspeed.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_htcp.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_hybla.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_illinois.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_input.c tcp: Correction to RFC number in comment 2014-10-30 19:53:34 -04:00
tcp_ipv4.c net: fix saving TX flow hash in sock for outgoing connections 2014-10-22 16:14:29 -04:00
tcp_lp.c tcp: remove in_flight parameter from cong_avoid() methods 2014-05-03 19:23:07 -04:00
tcp_memcontrol.c percpu_counter: add @gfp to percpu_counter_init() 2014-09-08 09:51:29 +09:00
tcp_metrics.c tcp: don't allow syn packets without timestamps to pass tcp_tw_recycle logic 2014-08-14 14:38:54 -07:00
tcp_minisocks.c tcp: change TCP_ECN prefixes to lower case 2014-09-29 14:41:22 -04:00
tcp_offload.c net: Remove gso_send_check as an offload callback 2014-09-26 00:22:47 -04:00
tcp_output.c net: skb_fclone_busy() needs to detect orphaned skb 2014-10-30 19:58:30 -04:00
tcp_probe.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_scalable.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_timer.c tcp: abort orphan sockets stalling on zero window probes 2014-10-01 16:27:52 -04:00
tcp_vegas.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_vegas.h
tcp_veno.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp_westwood.c net: tcp: split ack slow/fast events from cwnd_event 2014-09-29 00:13:10 -04:00
tcp_yeah.c tcp: whitespace fixes 2014-09-01 18:12:45 -07:00
tcp.c tcp: md5: do not use alloc_percpu() 2014-10-25 16:10:04 -04:00
tunnel4.c
udp_diag.c
udp_impl.h
udp_offload.c net: gso: use feature flag argument in all protocol gso handlers 2014-10-20 12:38:12 -04:00
udp_tunnel.c udp-tunnel: Add a few more UDP tunnel APIs 2014-09-19 15:57:15 -04:00
udp.c udp: remove else after return 2014-11-04 15:13:18 -05:00
udplite.c net: Eliminate no_check from protosw 2014-05-23 16:28:53 -04:00
xfrm4_input.c xfrm4: Add IPsec protocol multiplexer 2014-02-25 07:04:16 +01:00
xfrm4_mode_beet.c ipv4: ERROR: code indent should use tabs where possible 2013-12-26 13:43:21 -05:00
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c inetpeer: get rid of ip_id_count 2014-06-02 11:00:41 -07:00
xfrm4_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-05-24 00:32:30 -04:00
xfrm4_policy.c xfrm: Introduce xfrm_input_afinfo to access the the callbacks properly 2014-03-14 07:28:07 +01:00
xfrm4_protocol.c xfrm4: Remove duplicate semicolon 2014-06-30 07:49:47 +02:00
xfrm4_state.c inet: make no_pmtu_disc per namespace and kill ipv4_config 2013-12-18 16:58:20 -05:00
xfrm4_tunnel.c