path: root/Documentation/networking/ip-sysctl.txt
diff options
authorMaciej ┼╗enczykowski <maze@google.com>2017-11-07 21:52:09 -0800
committerDavid S. Miller <davem@davemloft.net>2017-11-11 15:13:02 +0900
commit2210d6b2f287d738eddf6b75f432126ce05450f8 (patch)
treee3d82015025096a7205fb124c045c5a5a665c1ec /Documentation/networking/ip-sysctl.txt
parent04bad8bda9e25afe676a6f4452f3b304c1fdea16 (diff)
net: ipv6: sysctl to specify IPv6 ND traffic class
Add a per-device sysctl to specify the default traffic class to use for kernel originated IPv6 Neighbour Discovery packets. Currently this includes: - Router Solicitation (ICMPv6 type 133) ndisc_send_rs() -> ndisc_send_skb() -> ip6_nd_hdr() - Neighbour Solicitation (ICMPv6 type 135) ndisc_send_ns() -> ndisc_send_skb() -> ip6_nd_hdr() - Neighbour Advertisement (ICMPv6 type 136) ndisc_send_na() -> ndisc_send_skb() -> ip6_nd_hdr() - Redirect (ICMPv6 type 137) ndisc_send_redirect() -> ndisc_send_skb() -> ip6_nd_hdr() and if the kernel ever gets around to generating RA's, it would presumably also include: - Router Advertisement (ICMPv6 type 134) (radvd daemon could pick up on the kernel setting and use it) Interface drivers may examine the Traffic Class value and translate the DiffServ Code Point into a link-layer appropriate traffic prioritization scheme. An example of mapping IETF DSCP values to IEEE 802.11 User Priority values can be found here: https://tools.ietf.org/html/draft-ietf-tsvwg-ieee-802-11 The expected primary use case is to properly prioritize ND over wifi. Testing: jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass 0 jzem22:~# echo -1 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass -bash: echo: write error: Invalid argument jzem22:~# echo 256 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass -bash: echo: write error: Invalid argument jzem22:~# echo 0 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass jzem22:~# echo 255 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass 255 jzem22:~# echo 34 > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass jzem22:~# cat /proc/sys/net/ipv6/conf/eth0/ndisc_tclass 34 jzem22:~# echo $[0xDC] > /proc/sys/net/ipv6/conf/eth0/ndisc_tclass jzem22:~# tcpdump -v -i eth0 icmp6 and src host jzem22.pgc and dst host fe80::1 tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes IP6 (class 0xdc, hlim 255, next-header ICMPv6 (58) payload length: 24) jzem22.pgc > fe80::1: [icmp6 sum ok] ICMP6, neighbor advertisement, length 24, tgt is jzem22.pgc, Flags [solicited] (based on original change written by Erik Kline, with minor changes) v2: fix 'suspicious rcu_dereference_check() usage' by explicitly grabbing the rcu_read_lock. Cc: Lorenzo Colitti <lorenzo@google.com> Signed-off-by: Erik Kline <ek@google.com> Signed-off-by: Maciej ┼╗enczykowski <maze@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking/ip-sysctl.txt')
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 54410a1d4065..d8676dda7fa6 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1732,6 +1732,15 @@ ndisc_notify - BOOLEAN
1 - Generate unsolicited neighbour advertisements when device is brought
up or hardware address changes.
+ndisc_tclass - INTEGER
+ The IPv6 Traffic Class to use by default when sending IPv6 Neighbor
+ Discovery (Router Solicitation, Router Advertisement, Neighbor
+ Solicitation, Neighbor Advertisement, Redirect) messages.
+ These 8 bits can be interpreted as 6 high order bits holding the DSCP
+ value and 2 low order bits representing ECN (which you probably want
+ to leave cleared).
+ 0 - (default)
mldv1_unsolicited_report_interval - INTEGER
The interval in milliseconds in which the next unsolicited
MLDv1 report retransmit will take place.