[RFC] Better document net.inet6 sysctls and prune dead sysctls

Garrett Cooper yanegomi at gmail.com
Mon Nov 26 22:42:21 UTC 2012


Hi all,
 	As noted in a previous thread, I set out to better document the 
net.inet6 sysctls after having to tweak the knobs to get things to work 
for TAHI, and this is the resulting draft (so far). I also took the 
liberty of removing the ip6_rr_prune and icmp6_redirtimeout sysctls 
because they weren't in use anywhere else in the sys/... portion of the 
tree. I was wondering if there are any points that should be 
corrected/clarified before I submit a PR with the resulting patch.
Thanks!
-Garrett

Index: sys/netinet6/in6_proto.c
===================================================================
--- sys/netinet6/in6_proto.c	(revision 242903)
+++ sys/netinet6/in6_proto.c	(working copy)
@@ -409,8 +409,6 @@
  VNET_DEFINE(int, ip6_auto_flowlabel) = 1;
  VNET_DEFINE(int, ip6_use_deprecated) = 1;/* allow deprecated addr
  					 * (RFC2462 5.5.4) */
-VNET_DEFINE(int, ip6_rr_prune) = 5;	/* router renumbering prefix
-					 * walk list every 5 sec. */
  VNET_DEFINE(int, ip6_mcast_pmtu) = 0;	/* enable pMTU discovery for multicast? */
  VNET_DEFINE(int, ip6_v6only) = 1;

@@ -443,7 +441,6 @@

  /* ICMPV6 parameters */
  VNET_DEFINE(int, icmp6_rediraccept) = 1;/* accept and process redirects */
-VNET_DEFINE(int, icmp6_redirtimeout) = 10 * 60;	/* 10 minutes */
  VNET_DEFINE(int, icmp6errppslim) = 100;		/* 100pps */
  /* control how to respond to NI queries */
  VNET_DEFINE(int, icmp6_nodeinfo) =
@@ -515,15 +512,20 @@
  }

  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_FORWARDING, forwarding, CTLFLAG_RW,
-	&VNET_NAME(ip6_forwarding), 0, "");
+	&VNET_NAME(ip6_forwarding), 0,
+	"Forward IPv6 packets via node.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
-	&VNET_NAME(ip6_sendredirects), 0, "");
+	&VNET_NAME(ip6_sendredirects), 0,
+	"Redirect IPv6 packets via node.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_DEFHLIM, hlim, CTLFLAG_RW,
-	&VNET_NAME(ip6_defhlim), 0, "");
+	&VNET_NAME(ip6_defhlim), 0,
+	"Default hop limit for IPv6 unicast packets.");
  SYSCTL_VNET_STRUCT(_net_inet6_ip6, IPV6CTL_STATS, stats, CTLFLAG_RW,
-	&VNET_NAME(ip6stat), ip6stat, "");
+	&VNET_NAME(ip6stat), ip6stat,
+	"IPv6 statistics.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_MAXFRAGPACKETS, maxfragpackets,
-	CTLFLAG_RW, &VNET_NAME(ip6_maxfragpackets), 0, "");
+	CTLFLAG_RW, &VNET_NAME(ip6_maxfragpackets), 0,
+	"Maximum number of fragmented packets to process.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_ACCEPT_RTADV, accept_rtadv,
  	CTLFLAG_RW, &VNET_NAME(ip6_accept_rtadv), 0,
  	"Default value of per-interface flag for accepting ICMPv6 Router"
@@ -535,57 +537,74 @@
  	"default router list.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_NORBIT_RAIF, norbit_raif, CTLFLAG_RW,
  	&VNET_NAME(ip6_norbit_raif), 0,
-	"Always set 0 to R flag in ICMPv6 NA messages when accepting RA"
-	" on the interface.");
+	"Always set 0 to R flag in ICMPv6 NA messages when accepting RA "
+	"on the interface.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_RFC6204W3, rfc6204w3,
  	CTLFLAG_RW, &VNET_NAME(ip6_rfc6204w3), 0,
  	"Accept the default router list from ICMPv6 RA messages even "
  	"when packet forwarding enabled.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
-	&VNET_NAME(ip6_keepfaith), 0, "");
+	&VNET_NAME(ip6_keepfaith), 0,
+	"");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_LOG_INTERVAL, log_interval,
-	CTLFLAG_RW, &VNET_NAME(ip6_log_interval), 0, "");
+	CTLFLAG_RW, &VNET_NAME(ip6_log_interval), 0,
+	"Period for throttling logging for high-traffic IPv6 operations (in "
+	"seconds).");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_HDRNESTLIMIT, hdrnestlimit,
-	CTLFLAG_RW, &VNET_NAME(ip6_hdrnestlimit), 0, "");
+	CTLFLAG_RW, &VNET_NAME(ip6_hdrnestlimit), 0,
+	"Maximum number of nested header options to process.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_DAD_COUNT, dad_count, CTLFLAG_RW,
-	&VNET_NAME(ip6_dad_count), 0, "");
+	&VNET_NAME(ip6_dad_count), 0,
+	"Number of Duplicate Address Detection attempts to try before "
+	"disabling interface.  Setting the value to 0 disables DAD.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_AUTO_FLOWLABEL, auto_flowlabel,
-	CTLFLAG_RW, &VNET_NAME(ip6_auto_flowlabel), 0, "");
+	CTLFLAG_RW, &VNET_NAME(ip6_auto_flowlabel), 0,
+	"Automatically attach a flowlabel to IPv6 packets.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_DEFMCASTHLIM, defmcasthlim,
-	CTLFLAG_RW, &VNET_NAME(ip6_defmcasthlim), 0, "");
+	CTLFLAG_RW, &VNET_NAME(ip6_defmcasthlim), 0,
+	"Default hop limit for IPv6 multicast packets.");
  SYSCTL_STRING(_net_inet6_ip6, IPV6CTL_KAME_VERSION, kame_version,
  	CTLFLAG_RD, __KAME_VERSION, 0, "");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_USE_DEPRECATED, use_deprecated,
-	CTLFLAG_RW, &VNET_NAME(ip6_use_deprecated), 0, "");
-SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_RR_PRUNE, rr_prune, CTLFLAG_RW,
-	&VNET_NAME(ip6_rr_prune), 0, "");
+	CTLFLAG_RW, &VNET_NAME(ip6_use_deprecated), 0,
+	"Use deprecated IPv6 support.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_USETEMPADDR, use_tempaddr,
-	CTLFLAG_RW, &VNET_NAME(ip6_use_tempaddr), 0, "");
+	CTLFLAG_RW, &VNET_NAME(ip6_use_tempaddr), 0,
+	"Use a temporary address when establishing address via SLAAC.");
  SYSCTL_VNET_PROC(_net_inet6_ip6, IPV6CTL_TEMPPLTIME, temppltime,
  	CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(ip6_temp_preferred_lifetime), 0,
-   	sysctl_ip6_temppltime, "I", "");
+   	sysctl_ip6_temppltime, "I",
+	"Preferred lifetime (in seconds) for a temporary address");
  SYSCTL_VNET_PROC(_net_inet6_ip6, IPV6CTL_TEMPVLTIME, tempvltime,
  	CTLTYPE_INT|CTLFLAG_RW, &VNET_NAME(ip6_temp_valid_lifetime), 0,
-   	sysctl_ip6_tempvltime, "I", "");
+   	sysctl_ip6_tempvltime, "I",
+	"Valid lifetime (in seconds) for a temporary address.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_V6ONLY, v6only,	CTLFLAG_RW,
-	&VNET_NAME(ip6_v6only), 0, "");
+	&VNET_NAME(ip6_v6only), 0,
+	"Allow IPv4-mapped IPv6 addresses per RFC 3493.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_AUTO_LINKLOCAL, auto_linklocal,
  	CTLFLAG_RW, &VNET_NAME(ip6_auto_linklocal), 0,
  	"Default value of per-interface flag for automatically adding an IPv6"
  	" link-local address to interfaces when attached");
  SYSCTL_VNET_STRUCT(_net_inet6_ip6, IPV6CTL_RIP6STATS, rip6stats, CTLFLAG_RW,
-	&VNET_NAME(rip6stat), rip6stat, "");
+	&VNET_NAME(rip6stat), rip6stat,
+	"RIP6 statistics.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_PREFER_TEMPADDR, prefer_tempaddr,
-	CTLFLAG_RW, &VNET_NAME(ip6_prefer_tempaddr), 0, "");
+	CTLFLAG_RW, &VNET_NAME(ip6_prefer_tempaddr), 0,
+	"Prefer the temporary address assigned when performing NUD.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_USE_DEFAULTZONE, use_defaultzone,
-	CTLFLAG_RW, &VNET_NAME(ip6_use_defzone), 0,"");
+	CTLFLAG_RW, &VNET_NAME(ip6_use_defzone), 0,
+	"Use the default scope zone if not explicitly provided.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_MAXFRAGS, maxfrags, CTLFLAG_RW,
-	&VNET_NAME(ip6_maxfrags), 0, "");
+	&VNET_NAME(ip6_maxfrags), 0,
+	"Maximum number of fragments to hold in the reassembly queue.");
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_MCAST_PMTU, mcast_pmtu, CTLFLAG_RW,
-	&VNET_NAME(ip6_mcast_pmtu), 0, "");
+	&VNET_NAME(ip6_mcast_pmtu), 0,
+	"Enable multicast pMTU discovery.");
  #ifdef IPSTEALTH
  SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_STEALTH, stealth, CTLFLAG_RW,
-	&VNET_NAME(ip6stealth), 0, "");
+	&VNET_NAME(ip6stealth), 0,
+	"IPv6 stealth mode. No hop limit decrementation on forwarding.");
  #endif

  #ifdef FLOWTABLE
@@ -594,35 +613,45 @@
  #define	V_ip6_output_flowtable_size	VNET(ip6_output_flowtable_size)

  SYSCTL_VNET_INT(_net_inet6_ip6, OID_AUTO, output_flowtable_size, CTLFLAG_RDTUN,
-    &VNET_NAME(ip6_output_flowtable_size), 2048,
-    "number of entries in the per-cpu output flow caches");
+	&VNET_NAME(ip6_output_flowtable_size), 2048,
+	"number of entries in the per-cpu output flow caches");
  #endif

  /* net.inet6.icmp6 */
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_REDIRACCEPT, rediraccept,
-	CTLFLAG_RW, &VNET_NAME(icmp6_rediraccept), 0, "");
-SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_REDIRTIMEOUT, redirtimeout,
-	CTLFLAG_RW, &VNET_NAME(icmp6_redirtimeout), 0, "");
+	CTLFLAG_RW, &VNET_NAME(icmp6_rediraccept), 0,
+	"Accept and process router redirects.");
  SYSCTL_VNET_STRUCT(_net_inet6_icmp6, ICMPV6CTL_STATS, stats, CTLFLAG_RW,
-	&VNET_NAME(icmp6stat), icmp6stat, "");
+	&VNET_NAME(icmp6stat), icmp6stat,
+	"ICMPv6 statistics.");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_PRUNE, nd6_prune, CTLFLAG_RW,
-	&VNET_NAME(nd6_prune), 0, "");
+	&VNET_NAME(nd6_prune), 0,
+	"Period (in seconds) for performing nd6 expiration checks of default "
+	"routes and prefix lists");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_DELAY, nd6_delay, CTLFLAG_RW,
-	&VNET_NAME(nd6_delay), 0, "");
+	&VNET_NAME(nd6_delay), 0,
+	"Delay (in seconds) before performing NUD on stale nodes.");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_UMAXTRIES, nd6_umaxtries,
-	CTLFLAG_RW, &VNET_NAME(nd6_umaxtries), 0, "");
+	CTLFLAG_RW, &VNET_NAME(nd6_umaxtries), 0,
+	"Maximum number of unicast queries to perform via nd6.");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_MMAXTRIES, nd6_mmaxtries,
-	CTLFLAG_RW, &VNET_NAME(nd6_mmaxtries), 0, "");
+	CTLFLAG_RW, &VNET_NAME(nd6_mmaxtries), 0,
+	"Maximum number of multicast queries to perform via nd6.");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_USELOOPBACK, nd6_useloopback,
-	CTLFLAG_RW, &VNET_NAME(nd6_useloopback), 0, "");
+	CTLFLAG_RW, &VNET_NAME(nd6_useloopback), 0,
+	"Use loopback interface for local traffic");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_NODEINFO, nodeinfo, CTLFLAG_RW,
-	&VNET_NAME(icmp6_nodeinfo), 0, "");
+	&VNET_NAME(icmp6_nodeinfo), 0,
+	"Node information state.");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ERRPPSLIMIT, errppslimit,
-	CTLFLAG_RW, &VNET_NAME(icmp6errppslim), 0, "");
+	CTLFLAG_RW, &VNET_NAME(icmp6errppslim), 0,
+	"Packets per second limit for ICMPv6 queries.");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_MAXNUDHINT, nd6_maxnudhint,
-	CTLFLAG_RW, &VNET_NAME(nd6_maxnudhint), 0, "");
+	CTLFLAG_RW, &VNET_NAME(nd6_maxnudhint), 0,
+	"Maximum number of upper layer hints.");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_DEBUG, nd6_debug, CTLFLAG_RW,
  	&VNET_NAME(nd6_debug), 0, "");
  SYSCTL_VNET_INT(_net_inet6_icmp6, ICMPV6CTL_ND6_ONLINKNSRFC4861,
-	nd6_onlink_ns_rfc4861, CTLFLAG_RW, &VNET_NAME(nd6_onlink_ns_rfc4861),
-	0, "Accept 'on-link' nd6 NS in compliance with RFC 4861.");
+	nd6_onlink_ns_rfc4861,
+	CTLFLAG_RW, &VNET_NAME(nd6_onlink_ns_rfc4861), 0,
+	"Accept 'on-link' nd6 NS in compliance with RFC 4861.");


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