Messages in this thread Patch in this message | | | Date | Mon, 29 Jun 2009 15:07:14 +0200 | From | Andreas Jaggi <> | Subject | [PATCH] gre: copy ToS/DiffServ bits to outer IP header |
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When tunneling IP traffic with GRE this patch makes it possible to export the ToS/DiffServ information to the outer IP header. This is particularly useful in a scenario with ESP/AH where the inner IP header is encrypted but the packet priority/DiffServ information should still be respected by the transporting routers (for example in an MPLS backbone network).
The feature is disabled by default and can be enabled on a per-interface basis (/proc/sys/net/ipv4/conf/ethX/gre_copy_tos).
Also does this bring Linux back in the game, as JunOS/IOS provide this for quite some time: http://www.cisco.com/en/US/docs/ios/11_3/feature/guide/greqos.html http://www.juniper.net/techpubs/software/junos/junos94/swconfig-services/configuring-a-gre-tunnel-to-copy-tos-bits-to-the-outer-ip-header.html
Signed-off-by: Andreas Jaggi <aj@open.ch>
diff -urN vanilla-linux-2.6.29.4/include/linux/sysctl.h gre-copy-tos/include/linux/sysctl.h --- vanilla-linux-2.6.29.4/include/linux/sysctl.h 2009-05-19 01:52:34.000000000 +0200 +++ gre-copy-tos/include/linux/sysctl.h 2009-06-29 14:23:07.000000000 +0200 @@ -490,6 +490,7 @@ NET_IPV4_CONF_ARP_IGNORE=19, NET_IPV4_CONF_PROMOTE_SECONDARIES=20, NET_IPV4_CONF_ARP_ACCEPT=21, + NET_IPV4_CONF_GRE_COPY_TOS=22, __NET_IPV4_CONF_MAX }; diff -urN vanilla-linux-2.6.29.4/kernel/sysctl_check.c gre-copy-tos/kernel/sysctl_check.c --- vanilla-linux-2.6.29.4/kernel/sysctl_check.c 2009-05-19 01:52:34.000000000 +0200 +++ gre-copy-tos/kernel/sysctl_check.c 2009-06-29 14:23:07.000000000 +0200 @@ -219,6 +219,7 @@ { NET_IPV4_CONF_ARP_IGNORE, "arp_ignore" }, { NET_IPV4_CONF_PROMOTE_SECONDARIES, "promote_secondaries" }, { NET_IPV4_CONF_ARP_ACCEPT, "arp_accept" }, + { NET_IPV4_CONF_GRE_COPY_TOS, "gre_copy_tos" }, {} }; diff -urN vanilla-linux-2.6.29.4/net/ipv4/devinet.c gre-copy-tos/net/ipv4/devinet.c --- vanilla-linux-2.6.29.4/net/ipv4/devinet.c 2009-05-19 01:52:34.000000000 +0200 +++ gre-copy-tos/net/ipv4/devinet.c 2009-06-29 14:23:07.000000000 +0200 @@ -1439,6 +1439,7 @@ DEVINET_SYSCTL_RW_ENTRY(ARP_ANNOUNCE, "arp_announce"), DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"), DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"), + DEVINET_SYSCTL_RW_ENTRY(GRE_COPY_TOS, "gre_copy_tos"), DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"), DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"), diff -urN vanilla-linux-2.6.29.4/net/ipv4/ip_gre.c gre-copy-tos/net/ipv4/ip_gre.c --- vanilla-linux-2.6.29.4/net/ipv4/ip_gre.c 2009-05-19 01:52:34.000000000 +0200 +++ gre-copy-tos/net/ipv4/ip_gre.c 2009-06-29 14:23:24.000000000 +0200 @@ -610,6 +610,7 @@ struct net_device_stats *stats = &tunnel->dev->stats; struct iphdr *old_iph = ip_hdr(skb); struct iphdr *tiph; + struct in_device *in_dev; u8 tos; __be16 df; struct rtable *rt; /* Route to the other host */ @@ -677,11 +678,13 @@ } tos = tiph->tos; - if (tos&1) { + in_dev = in_dev_get(dev); + if ((in_dev && IN_DEV_ORCONF(in_dev, GRE_COPY_TOS)) || tos&1) { if (skb->protocol == htons(ETH_P_IP)) tos = old_iph->tos; tos &= ~1; } + in_dev_put(in_dev); { struct flowi fl = { .oif = tunnel->parms.link,
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