ipv6: Update ip-sysctl.txt documentation for recent changes to accept_ra and forwarding

Documentation for recent changes to the tunables accept_ra and
forwarding.

Signed-off-by: Thomas Graf <tgraf@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index f350c69b2bb4f807340416ffe7cf29cc8b02e662..c7165f4cb7927a152ec547caeecb393f5ad3c27e 100644 (file)
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1014,6 +1014,12 @@ conf/interface/*:
 accept_ra - BOOLEAN
        Accept Router Advertisements; autoconfigure using them.
 
+       Possible values are:
+               0 Do not accept Router Advertisements.
+               1 Accept Router Advertisements if forwarding is disabled.
+               2 Overrule forwarding behaviour. Accept Router Advertisements
+                 even if forwarding is enabled.
+
        Functional default: enabled if local forwarding is disabled.
                            disabled if local forwarding is enabled.
 
@@ -1075,7 +1081,12 @@ forwarding - BOOLEAN
        Note: It is recommended to have the same setting on all
        interfaces; mixed router/host scenarios are rather uncommon.
 
-       FALSE:
+       Possible values are:
+               0 Forwarding disabled
+               1 Forwarding enabled
+               2 Forwarding enabled (Hybrid Mode)
+
+       FALSE (0):
 
        By default, Host behaviour is assumed.  This means:
 
@@ -1085,18 +1096,24 @@ forwarding - BOOLEAN
           Advertisements (and do autoconfiguration).
        4. If accept_redirects is TRUE (default), accept Redirects.
 
-       TRUE:
+       TRUE (1):
 
        If local forwarding is enabled, Router behaviour is assumed.
        This means exactly the reverse from the above:
 
        1. IsRouter flag is set in Neighbour Advertisements.
        2. Router Solicitations are not sent.
-       3. Router Advertisements are ignored.
+       3. Router Advertisements are ignored unless accept_ra is 2.
        4. Redirects are ignored.
 
-       Default: FALSE if global forwarding is disabled (default),
-                otherwise TRUE.
+       TRUE (2):
+
+       Hybrid mode. Same behaviour as TRUE, except for:
+
+       2. Router Solicitations are being sent when necessary.
+
+       Default: 0 (disabled) if global forwarding is disabled (default),
+                otherwise 1 (enabled).
 
 hop_limit - INTEGER
        Default Hop Limit to set.