linux/net/ipv4
Tom Quetchenbach f5fff5dc8a tcp: advertise MSS requested by user
I'm trying to use the TCP_MAXSEG option to setsockopt() to set the MSS
for both sides of a bidirectional connection.

man tcp says: "If this option is set before connection establishment, it
also changes the MSS value announced to the other end in the initial
packet."

However, the kernel only uses the MTU/route cache to set the advertised
MSS. That means if I set the MSS to, say, 500 before calling connect(),
I will send at most 500-byte packets, but I will still receive 1500-byte
packets in reply.

This is a bug, either in the kernel or the documentation.

This patch (applies to latest net-2.6) reduces the advertised value to
that requested by the user as long as setsockopt() is called before
connect() or accept(). This seems like the behavior that one would
expect as well as that which is documented.

I've tried to make sure that things that depend on the advertised MSS
are set correctly.

Signed-off-by: Tom Quetchenbach <virtualphtn@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-21 00:21:51 -07:00
..
ipvs net: Use hton[sl]() instead of __constant_hton[sl]() where applicable 2008-09-20 22:20:49 -07:00
netfilter nf_nat: use secure_ipv4_port_ephemeral() for NAT port randomization 2008-08-18 21:32:32 -07:00
af_inet.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2008-07-26 20:23:44 -07:00
ah4.c [IPSEC]: Fix bogus usage of u64 on input sequence number 2008-02-12 22:50:35 -08:00
arp.c mib: add net to NET_INC_STATS_BH 2008-07-16 20:31:16 -07:00
cipso_ipv4.c cipso: Relax too much careful cipso hash function. 2008-05-13 23:23:55 -07:00
datagram.c mib: add net to IP_INC_STATS_BH 2008-07-16 20:20:11 -07:00
devinet.c ipv: Re-enable IP when MTU > 68 2008-09-02 17:28:58 -07:00
esp4.c ipsec: Interfamily IPSec BEET 2008-08-06 02:39:30 -07:00
fib_frontend.c netns: add namespace parameter to rt_cache_flush 2008-07-05 19:00:44 -07:00
fib_hash.c netns: add namespace parameter to rt_cache_flush 2008-07-05 19:00:44 -07:00
fib_lookup.h [IPV4] FIB_HASH: Reduce memory needs and speedup lookups 2008-01-28 15:02:46 -08:00
fib_rules.c net: add fib_rules_ops to flush_cache method 2008-07-05 19:01:28 -07:00
fib_semantics.c Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2008-06-13 20:52:39 -07:00
fib_trie.c proc: consolidate per-net single-release callers 2008-07-18 04:07:44 -07:00
icmp.c icmp: icmp_sk() should not use smp_processor_id() in preemptible code 2008-08-23 04:43:33 -07:00
igmp.c netns: Fix crash by making igmp per namespace 2008-08-13 16:15:57 -07:00
inet_connection_sock.c net: convert BUG_TRAP to generic WARN_ON 2008-07-25 21:43:18 -07:00
inet_diag.c inet_diag: Add empty bucket optimization to inet_diag too 2008-08-28 01:09:54 -07:00
inet_fragment.c net: convert BUG_TRAP to generic WARN_ON 2008-07-25 21:43:18 -07:00
inet_hashtables.c net: convert BUG_TRAP to generic WARN_ON 2008-07-25 21:43:18 -07:00
inet_lro.c net/inet_lro: remove setting skb->ip_summed when not LRO-able 2008-06-27 20:09:00 -07:00
inet_timewait_sock.c netns : fix kernel panic in timewait socket destruction 2008-09-08 13:17:27 -07:00
inetpeer.c net: remove CVS keywords 2008-06-11 21:00:38 -07:00
ip_forward.c mib: add net to IP_INC_STATS_BH 2008-07-16 20:20:11 -07:00
ip_fragment.c net: convert BUG_TRAP to generic WARN_ON 2008-07-25 21:43:18 -07:00
ip_gre.c Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2008-05-25 23:26:10 -07:00
ip_input.c mib: put ip statistics on struct net 2008-07-18 04:02:42 -07:00
ip_options.c net: remove CVS keywords 2008-06-11 21:00:38 -07:00
ip_output.c net: convert BUG_TRAP to generic WARN_ON 2008-07-25 21:43:18 -07:00
ip_sockglue.c net: remove CVS keywords 2008-06-11 21:00:38 -07:00
ipcomp.c ipcomp: Fix warnings after ipcomp consolidation. 2008-07-27 03:59:24 -07:00
ipconfig.c netns: Use net_eq() to compare net-namespaces for optimization. 2008-07-19 22:34:43 -07:00
ipip.c net: remove CVS keywords 2008-06-11 21:00:38 -07:00
ipmr.c netns: Use net_eq() to compare net-namespaces for optimization. 2008-07-19 22:34:43 -07:00
Kconfig ipsec: ipcomp - Merge IPComp implementations 2008-07-25 02:54:40 -07:00
Makefile [UDP]: Revert udplite and code split. 2008-03-06 16:22:02 -08:00
netfilter.c [NETFILTER]: Add partial checksum validation helper 2008-04-14 11:15:49 +02:00
proc.c tcp: MD5: Use MIB counter instead of warning for MD5 mismatch. 2008-07-30 03:27:25 -07:00
protocol.c net: remove CVS keywords 2008-06-11 21:00:38 -07:00
raw.c mib: add net to IP_INC_STATS 2008-07-16 20:19:49 -07:00
route.c Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2008-08-29 23:06:00 -07:00
syncookies.c syncookies: Make sure ECN is disabled 2008-07-26 02:21:54 -07:00
sysctl_net_ipv4.c net: Add missing extra2 parameter for ip_default_ttl sysctl 2008-08-03 14:06:44 -07:00
tcp.c net: convert BUG_TRAP to generic WARN_ON 2008-07-25 21:43:18 -07:00
tcp_bic.c [TCP]: BIC web page link is corrected. 2008-02-28 22:14:32 -08:00
tcp_cong.c tcp: Limit cwnd growth when deferring for GSO 2008-04-29 03:13:52 -07:00
tcp_cubic.c rename div64_64 to div64_u64 2008-05-01 08:03:58 -07:00
tcp_diag.c net: remove CVS keywords 2008-06-11 21:00:38 -07:00
tcp_highspeed.c [TCP]: Cong.ctrl modules: remove unused good_ack from cong_avoid 2008-01-28 14:55:41 -08:00
tcp_htcp.c [TCP]: Cong.ctrl modules: remove unused good_ack from cong_avoid 2008-01-28 14:55:41 -08:00
tcp_hybla.c net: fix returning void-valued expression warnings 2008-05-01 02:47:38 -07:00
tcp_illinois.c [TCP]: Cong.ctrl modules: remove unused good_ack from cong_avoid 2008-01-28 14:55:41 -08:00
tcp_input.c tcp: don't clear lost_skb_hint when not necessary 2008-09-20 21:25:52 -07:00
tcp_ipv4.c tcp: advertise MSS requested by user 2008-09-21 00:21:51 -07:00
tcp_lp.c [TCP]: Cong.ctrl modules: remove unused good_ack from cong_avoid 2008-01-28 14:55:41 -08:00
tcp_minisocks.c tcp: (whitespace only) fix confusing indentation 2008-08-07 20:27:45 -07:00
tcp_output.c tcp: advertise MSS requested by user 2008-09-21 00:21:51 -07:00
tcp_probe.c tcp: correct kcalloc usage 2008-07-10 16:51:32 -07:00
tcp_scalable.c [TCP]: Cong.ctrl modules: remove unused good_ack from cong_avoid 2008-01-28 14:55:41 -08:00
tcp_timer.c net: convert BUG_TRAP to generic WARN_ON 2008-07-25 21:43:18 -07:00
tcp_vegas.c net: fix returning void-valued expression warnings 2008-05-01 02:47:38 -07:00
tcp_vegas.h [TCP]: congestion control API pass RTT in microseconds 2007-07-31 02:27:57 -07:00
tcp_veno.c net: fix returning void-valued expression warnings 2008-05-01 02:47:38 -07:00
tcp_westwood.c [TCP]: congestion control API pass RTT in microseconds 2007-07-31 02:27:57 -07:00
tcp_yeah.c [TCP]: Cong.ctrl modules: remove unused good_ack from cong_avoid 2008-01-28 14:55:41 -08:00
tunnel4.c [IPV4] TUNNEL4: Fix incoming packet length check for inter-protocol tunnel. 2008-06-05 04:02:33 +09:00
udp.c udp: Drop socket lock for encapsulated packets 2008-08-09 00:35:05 -07:00
udp_impl.h net: change proto destroy method to return void 2008-06-14 17:04:49 -07:00
udplite.c mib: put udplite statistics on struct net 2008-07-18 04:03:45 -07:00
xfrm4_input.c [IPSEC]: Fix transport-mode async resume on intput without netfilter 2008-01-28 15:00:10 -08:00
xfrm4_mode_beet.c ipsec: Interfamily IPSec BEET 2008-08-06 02:39:30 -07:00
xfrm4_mode_transport.c [IPSEC]: Use IPv6 calling convention as the convention for x->mode->output 2007-10-10 16:55:54 -07:00
xfrm4_mode_tunnel.c xfrm: fix fragmentation for ipv4 xfrm tunnel 2008-06-17 16:38:23 -07:00
xfrm4_output.c [IPSEC]: Fix inter address family IPsec tunnel handling. 2008-03-24 14:51:51 -07:00
xfrm4_policy.c [NET] NETNS: Omit net_device->nd_net without CONFIG_NET_NS. 2008-03-26 04:39:53 +09:00
xfrm4_state.c [IPSEC]: Fix BEET output 2008-03-26 16:51:09 -07:00
xfrm4_tunnel.c [IPCOMP]: Fix reception of incompressible packets 2008-01-31 19:27:24 -08:00