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ipv6: send NEWLINK on RA managed/otherconf changes

PATCH Applied Marius Tomaschewski 2 participants 4 messages Aug 31, 2015

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Networking Network drivers IPv4/IPv6
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Marius Tomaschewski

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#0 lore raw

PATCH 1/1 ipv6: send NEWLINK on RA managed/otherconf changes

The kernel is applying the RA managed/otherconf flags silently and forgets to send ifinfo notify to inform about their change when the router provides a zero reachable_time and retrans_timer as dnsmasq and many routers send it, which just means unspecified by this router and the host should continue using whatever value it is already using. Userspace may monitor the ifinfo notifications to activate dhcpv6.

Signed-off-by Marius Tomaschewski <[email protected]>
net/ipv6/ndisc.c +5 -0
index c53331c..99ea9dd 100644
@@ -1074,6 +1074,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 	struct ndisc_options ndopts;
 	int optlen;
 	unsigned int pref = 0;
+	__u32 old_if_flags;
 
 	__u8 *opt = (__u8 *)(ra_msg + 1);
 

@@ -1144,6 +1145,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 	 * Remember the managed/otherconf flags from most recently
 	 * received RA message (RFC 2462) -- yoshfuji
 	 */
+	old_if_flags = in6_dev->if_flags;
 	in6_dev->if_flags = (in6_dev->if_flags & ~(IF_RA_MANAGED |
 				IF_RA_OTHERCONF)) |
 				(ra_msg->icmph.icmp6_addrconf_managed ?

@@ -1151,6 +1153,9 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 				(ra_msg->icmph.icmp6_addrconf_other ?
 					IF_RA_OTHERCONF : 0);
 
+	if (old_if_flags != in6_dev->if_flags)
+		inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
+
 	if (!in6_dev->cnf.accept_ra_defrtr) {
 		ND_PRINTK(2, info,
 			  "RA: %s, defrtr is false for dev: %s\n",
Signature · 1 line
2.1.4
maintainer Applied
#1 lore raw

From: Marius Tomaschewski <[email protected]>
Date: Mon, 31 Aug 2015 15:59:22 +0200

Quoted 8 lines

The kernel is applying the RA managed/otherconf flags silently and forgets to send ifinfo notify to inform about their change when the router provides a zero reachable_time and retrans_timer as dnsmasq and many routers send it, which just means unspecified by this router and the host should continue using whatever value it is already using. Userspace may monitor the ifinfo notifications to activate dhcpv6.

Signed-off-by Marius Tomaschewski <[email protected]>

Applied, but more ideally this function should emit only a single NEWLINK message rather than potentially 3.

author
#2 lore raw

Am 01.09.2015 um 00:13 schrieb David Miller:

Quoted 10 lines

From: Marius Tomaschewski <[email protected]>
Date: Mon, 31 Aug 2015 15:59:22 +0200

Quoted 7 lines

The kernel is applying the RA managed/otherconf flags silently and forgets to send ifinfo notify to inform about their change when the router provides a zero reachable_time and retrans_timer as dnsmasq and many routers send it, which just means unspecified by this router and the host should continue using whatever value it is already using. Userspace may monitor the ifinfo notifications to activate dhcpv6.

Quoted 4 lines
Quoted 1 line
Signed-off-by Marius Tomaschewski <[email protected]>

Applied, but more ideally this function should emit only a single NEWLINK message rather than potentially 3.

Yes, you're right of course.

I've attached a follow-up patch doing this. Please let me know if you need it in a separate mail.

Gruesse / Regards,
Marius Tomaschewski <[email protected]>, <[email protected]>

Signature · 3 lines
 SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard,
 Dilip Upmanyu, Graham Norton, HRB 21284 (AG Nürnberg),
 Maxfeldstraße 5, 90409 Nürnberg, Germany
Quoted 1 line

From b6b55b5383c9b89cfd5ad9b4584c044c6c8d3722 Mon Sep 17 00:00:00 2001

From: Marius Tomaschewski <[email protected]>
Date: Tue, 1 Sep 2015 01:40:57 +0200
Subject: [PATCH] ipv6: send only one NEWLINK when RA causes changes

Signed-off-by Marius Tomaschewski <[email protected]>
net/ipv6/ndisc.c +10 -3
index 99ea9dd..7baca60 100644
@@ -1075,6 +1075,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 	int optlen;
 	unsigned int pref = 0;
 	__u32 old_if_flags;
+	int send_ifinfo_notify = 0;
 
 	__u8 *opt = (__u8 *)(ra_msg + 1);
 

@@ -1154,7 +1155,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
 					IF_RA_OTHERCONF : 0);
 
 	if (old_if_flags != in6_dev->if_flags)
-		inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
+		send_ifinfo_notify = 1;
 
 	if (!in6_dev->cnf.accept_ra_defrtr) {
 		ND_PRINTK(2, info,

@@ -1259,7 +1260,7 @@ skip_defrtr:
 				rtime = HZ/10;
 			NEIGH_VAR_SET(in6_dev->nd_parms, RETRANS_TIME, rtime);
 			in6_dev->tstamp = jiffies;
-			inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
+			send_ifinfo_notify = 1;
 		}
 
 		rtime = ntohl(ra_msg->reachable_time);

@@ -1276,11 +1277,17 @@ skip_defrtr:
 					      GC_STALETIME, 3 * rtime);
 				in6_dev->nd_parms->reachable_time = neigh_rand_reach_time(rtime);
 				in6_dev->tstamp = jiffies;
-				inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
+				send_ifinfo_notify = 1;
 			}
 		}
 	}
 
+	/*
+	 *	Send a notify if RA changed managed/otherconf flags or timer settings
+	 */
+	if (send_ifinfo_notify)
+		inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
+
 skip_linkparms:
 
 	/*
Signature · 1 line
2.1.4
maintainer
#3 lore raw

From: Marius Tomaschewski <[email protected]>
Date: Tue, 1 Sep 2015 01:43:39 +0200

Quoted 2 lines

I've attached a follow-up patch doing this. Please let me know if you need it in a separate mail.

I want it in a separate mail, and please use "bool" for the type.