Re: Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast usage)

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* Re: Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast usage)
       [not found] <no.id>
@ 2003-07-17  2:23 ` kuznet
  2003-07-17  2:23   ` David S. Miller
  2003-07-17  8:38   ` Mika Liljeberg
  0 siblings, 2 replies; 5+ messages in thread
From: kuznet @ 2003-07-17  2:23 UTC (permalink / raw)
  To: kuznet; +Cc: davem, jmorris, mika.liljeberg, pekkas, netdev

Hello!

Here it is. Please, review and complain.

1. Recognition of reserved anycasts is removed from ipv6_addr_type().
   Flag IPV6_ADDR_ANYCAST is removed as well.
2. Some meaningless noop code checking for anycast which are not going
   to happen is removed from ndisc.c
3. ipv6_unicast_destination() replaces suboptimal ipv6_chk_acast_addr()
   in data paths.

Alexey



# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#	           ChangeSet	1.1469  -> 1.1470 
#	  net/ipv6/anycast.c	1.5     -> 1.6    
#	include/net/ip6_route.h	1.10    -> 1.11   
#	     net/ipv6/icmp.c	1.36    -> 1.37   
#	 net/ipv6/tcp_ipv6.c	1.64    -> 1.65   
#	    net/ipv6/ndisc.c	1.52    -> 1.53   
#	    net/ipv6/route.c	1.50    -> 1.51   
#	  include/net/ipv6.h	1.22    -> 1.23   
#	 net/ipv6/addrconf.c	1.58    -> 1.59   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 03/07/17	kuznet@oops.inr.ac.ru	1.1470
# Many files:
#   sanitize IPv6 anycast address support
# --------------------------------------------
#
diff -Nru a/include/net/ip6_route.h b/include/net/ip6_route.h
--- a/include/net/ip6_route.h	Thu Jul 17 06:13:09 2003
+++ b/include/net/ip6_route.h	Thu Jul 17 06:13:09 2003
@@ -45,7 +45,8 @@
 					   void *rtattr);
 
 extern int			ip6_rt_addr_add(struct in6_addr *addr,
-						struct net_device *dev);
+						struct net_device *dev,
+						int anycast);
 
 extern int			ip6_rt_addr_del(struct in6_addr *addr,
 						struct net_device *dev);
@@ -116,6 +117,13 @@
 	np->daddr_cache = daddr;
 	np->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
 	write_unlock(&sk->sk_dst_lock);
+}
+
+static inline int ipv6_unicast_destination(struct sk_buff *skb)
+{
+	struct rt6_info *rt = (struct rt6_info *) skb->dst;
+
+	return rt->rt6_flags & RTF_LOCAL;
 }
 
 #endif
diff -Nru a/include/net/ipv6.h b/include/net/ipv6.h
--- a/include/net/ipv6.h	Thu Jul 17 06:13:09 2003
+++ b/include/net/ipv6.h	Thu Jul 17 06:13:09 2003
@@ -51,7 +51,7 @@
 /*
  *	Addr type
  *	
- *	type	-	unicast | multicast | anycast
+ *	type	-	unicast | multicast
  *	scope	-	local	| site	    | global
  *	v4	-	compat
  *	v4mapped
@@ -63,7 +63,6 @@
 
 #define IPV6_ADDR_UNICAST      	0x0001U	
 #define IPV6_ADDR_MULTICAST    	0x0002U	
-#define IPV6_ADDR_ANYCAST	0x0004U
 
 #define IPV6_ADDR_LOOPBACK	0x0010U
 #define IPV6_ADDR_LINKLOCAL	0x0020U
diff -Nru a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
--- a/net/ipv6/addrconf.c	Thu Jul 17 06:13:09 2003
+++ b/net/ipv6/addrconf.c	Thu Jul 17 06:13:09 2003
@@ -209,15 +209,8 @@
 		};
 		return type;
 	}
-	/* check for reserved anycast addresses */
-	
-	if ((st & htonl(0xE0000000)) &&
-	    ((addr->s6_addr32[2] == htonl(0xFDFFFFFF) &&
-	    (addr->s6_addr32[3] | htonl(0x7F)) == (u32)~0) ||
-	    (addr->s6_addr32[2] == 0 && addr->s6_addr32[3] == 0)))
-		type = IPV6_ADDR_ANYCAST;
-	else
-		type = IPV6_ADDR_UNICAST;
+
+	type = IPV6_ADDR_UNICAST;
 
 	/* Consider all addresses with the first three bits different of
 	   000 and 111 as finished.
@@ -2552,7 +2545,7 @@
 
 	switch (event) {
 	case RTM_NEWADDR:
-		ip6_rt_addr_add(&ifp->addr, ifp->idev->dev);
+		ip6_rt_addr_add(&ifp->addr, ifp->idev->dev, 0);
 		break;
 	case RTM_DELADDR:
 		addrconf_leave_solict(ifp->idev->dev, &ifp->addr);
diff -Nru a/net/ipv6/anycast.c b/net/ipv6/anycast.c
--- a/net/ipv6/anycast.c	Thu Jul 17 06:13:09 2003
+++ b/net/ipv6/anycast.c	Thu Jul 17 06:13:09 2003
@@ -96,6 +96,13 @@
 	return onlink;
 }
 
+static inline ipv6_reserved_anycast(const struct in6_addr *addr)
+{
+	return (addr->s6_addr32[0] & htonl(0xE0000000)) &&
+		((addr->s6_addr32[2] == htonl(0xFDFFFFFF) &&
+		  (addr->s6_addr32[3] | htonl(0x7F)) == (u32)~0) ||
+		 (addr->s6_addr32[2] == 0 && addr->s6_addr32[3] == 0));
+}
 
 /*
  *	socket join an anycast group
@@ -112,6 +119,8 @@
 
 	if (ipv6_addr_type(addr) & IPV6_ADDR_MULTICAST)
 		return -EINVAL;
+	if (ipv6_chk_addr(addr, NULL))
+		return -EINVAL;
 
 	pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL);
 	if (pac == NULL)
@@ -172,8 +181,7 @@
 			err = -EPERM;
 		if (err)
 			goto out_dev_put;
-	} else if (!(ipv6_addr_type(addr) & IPV6_ADDR_ANYCAST) &&
-		   !capable(CAP_NET_ADMIN)) {
+	} else if (!ipv6_reserved_anycast(addr) && !capable(CAP_NET_ADMIN)) {
 		err = -EPERM;
 		goto out_dev_put;
 	}
@@ -347,7 +355,7 @@
 	idev->ac_list = aca;
 	write_unlock_bh(&idev->lock);
 
-	ip6_rt_addr_add(&aca->aca_addr, dev);
+	ip6_rt_addr_add(&aca->aca_addr, dev, 1);
 
 	addrconf_join_solict(dev, &aca->aca_addr);
 
diff -Nru a/net/ipv6/icmp.c b/net/ipv6/icmp.c
--- a/net/ipv6/icmp.c	Thu Jul 17 06:13:09 2003
+++ b/net/ipv6/icmp.c	Thu Jul 17 06:13:09 2003
@@ -415,8 +415,7 @@
 
 	saddr = &skb->nh.ipv6h->daddr;
 
-	if (ipv6_addr_type(saddr) & IPV6_ADDR_MULTICAST ||
-	    ipv6_chk_acast_addr(0, saddr)) 
+	if (!ipv6_unicast_destination(skb))
 		saddr = NULL;
 
 	memcpy(&tmp_hdr, icmph, sizeof(tmp_hdr));
diff -Nru a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
--- a/net/ipv6/ndisc.c	Thu Jul 17 06:13:09 2003
+++ b/net/ipv6/ndisc.c	Thu Jul 17 06:13:09 2003
@@ -785,8 +785,7 @@
 			ipv6_addr_all_nodes(&maddr);
 			ndisc_send_na(dev, NULL, &maddr, &ifp->addr, 
 				      ifp->idev->cnf.forwarding, 0, 
-				      ipv6_addr_type(&ifp->addr)&IPV6_ADDR_ANYCAST ? 0 : 1, 
-				      1);
+				      1, 1);
 			in6_ifa_put(ifp);
 			return;
 		}
@@ -809,8 +808,7 @@
 			if (neigh || !dev->hard_header) {
 				ndisc_send_na(dev, neigh, saddr, &ifp->addr, 
 					      ifp->idev->cnf.forwarding, 1, 
-					      ipv6_addr_type(&ifp->addr)&IPV6_ADDR_ANYCAST ? 0 : 1, 
-					      1);
+					      1, 1);
 				if (neigh)
 					neigh_release(neigh);
 			}
diff -Nru a/net/ipv6/route.c b/net/ipv6/route.c
--- a/net/ipv6/route.c	Thu Jul 17 06:13:09 2003
+++ b/net/ipv6/route.c	Thu Jul 17 06:13:09 2003
@@ -1256,7 +1256,7 @@
  *	Add address
  */
 
-int ip6_rt_addr_add(struct in6_addr *addr, struct net_device *dev)
+int ip6_rt_addr_add(struct in6_addr *addr, struct net_device *dev, int anycast)
 {
 	struct rt6_info *rt = ip6_dst_alloc();
 
@@ -1275,6 +1275,8 @@
 	rt->u.dst.obsolete = -1;
 
 	rt->rt6i_flags = RTF_UP | RTF_NONEXTHOP;
+	if (!anycast)
+		rt->rt6i_flags |= RTF_LOCAL;
 	rt->rt6i_nexthop = ndisc_get_neigh(rt->rt6i_dev, &rt->rt6i_gateway);
 	if (rt->rt6i_nexthop == NULL) {
 		dst_free((struct dst_entry *) rt);
diff -Nru a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
--- a/net/ipv6/tcp_ipv6.c	Thu Jul 17 06:13:09 2003
+++ b/net/ipv6/tcp_ipv6.c	Thu Jul 17 06:13:09 2003
@@ -971,7 +971,7 @@
 	if (th->rst)
 		return;
 
-	if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr))
+	if (!ipv6_unicast_destination(skb))
 		return; 
 
 	/*
@@ -1175,8 +1175,7 @@
 	if (skb->protocol == htons(ETH_P_IP))
 		return tcp_v4_conn_request(sk, skb);
 
-	/* FIXME: do the same check for anycast */
-	if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr))
+	if (!ipv6_unicast_destination(skb))
 		goto drop; 
 
 	/*

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast usage)
  2003-07-17  2:23 ` Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast usage) kuznet
@ 2003-07-17  2:23   ` David S. Miller
  2003-07-17  8:38   ` Mika Liljeberg
  1 sibling, 0 replies; 5+ messages in thread
From: David S. Miller @ 2003-07-17  2:23 UTC (permalink / raw)
  To: kuznet; +Cc: kuznet, jmorris, mika.liljeberg, pekkas, netdev

On Thu, 17 Jul 2003 06:23:52 +0400 (MSD)
kuznet@ms2.inr.ac.ru wrote:

> Here it is. Please, review and complain.

If Pekka agrees with semantics, the patch looks sound
by my eyes.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast usage)
  2003-07-17  2:23 ` Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast usage) kuznet
  2003-07-17  2:23   ` David S. Miller
@ 2003-07-17  8:38   ` Mika Liljeberg
  2003-07-17  9:06     ` Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast kuznet
  1 sibling, 1 reply; 5+ messages in thread
From: Mika Liljeberg @ 2003-07-17  8:38 UTC (permalink / raw)
  To: kuznet; +Cc: kuznet, davem, jmorris, pekkas, netdev

Alexey,

On Thu, 2003-07-17 at 05:23, kuznet@ms2.inr.ac.ru wrote:
> diff -Nru a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
> --- a/net/ipv6/ndisc.c	Thu Jul 17 06:13:09 2003
> +++ b/net/ipv6/ndisc.c	Thu Jul 17 06:13:09 2003
> @@ -785,8 +785,7 @@
>  			ipv6_addr_all_nodes(&maddr);
>  			ndisc_send_na(dev, NULL, &maddr, &ifp->addr, 
>  				      ifp->idev->cnf.forwarding, 0, 
> -				      ipv6_addr_type(&ifp->addr)&IPV6_ADDR_ANYCAST ? 0 : 1, 
> -				      1);
> +				      1, 1);
>  			in6_ifa_put(ifp);
>  			return;
>  		}
> @@ -809,8 +808,7 @@
>  			if (neigh || !dev->hard_header) {
>  				ndisc_send_na(dev, neigh, saddr, &ifp->addr, 
>  					      ifp->idev->cnf.forwarding, 1, 
> -					      ipv6_addr_type(&ifp->addr)&IPV6_ADDR_ANYCAST ? 0 : 1, 
> -					      1);
> +					      1, 1);
>  				if (neigh)
>  					neigh_release(neigh);
>  			}

I'm not sure you can just remove these. It seems possible (?) to have
the anycast address configured on one of the interfaces as a unicast at
the same time. I.e., one of the anycast members could own the address.

For what it's worth, I think you have the right semantics.

	MikaL

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast
  2003-07-17  8:38   ` Mika Liljeberg
@ 2003-07-17  9:06     ` kuznet
  2003-07-17  9:32       ` Mika Liljeberg
  0 siblings, 1 reply; 5+ messages in thread
From: kuznet @ 2003-07-17  9:06 UTC (permalink / raw)
  To: Mika Liljeberg; +Cc: davem, jmorris, pekkas, netdev

Hello!

> I'm not sure you can just remove these. It seems possible (?) to have
> the anycast address configured on one of the interfaces as a unicast at
> the same time. I.e., one of the anycast members could own the address.

They cannot intersect, otherwise RTF_LOCAL thing will not work.

I deliberately blocked attempt to add a local address as anycast
in anycast.c, see another chunk. But even that check is not necessary:
non-superuser may listen only for reserved unicasts, which are
excluded from allowed local addresses by policy. Kernel does not need even
to worry about this.

Actually, the test in ndisc.c was bogus by another reason:
inet_addr_type() checks only for reserved anycasts and non-reserved unicasts,
which would conflict with local addresses, were not detected in any case.

Alexey

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast
  2003-07-17  9:06     ` Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast kuznet
@ 2003-07-17  9:32       ` Mika Liljeberg
  0 siblings, 0 replies; 5+ messages in thread
From: Mika Liljeberg @ 2003-07-17  9:32 UTC (permalink / raw)
  To: kuznet; +Cc: davem, jmorris, pekkas, netdev

On Thu, 2003-07-17 at 12:06, kuznet@ms2.inr.ac.ru wrote:
> They cannot intersect, otherwise RTF_LOCAL thing will not work.
> 
> I deliberately blocked attempt to add a local address as anycast
> in anycast.c, see another chunk.

Ok, I missed that one.

I guess it's safe to assume that the anycast and unicast spaces will not
intersect, even though the addresses are allocated from the same range.
I was wondering how to dynamically assign anycast addresses. In theory
one could abuse the unicast address assignment mechanisms (in the
absence of anything else users might be tempted to try this). But that's
a different issue.

	MikaL

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2003-07-17  9:32 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
     [not found] <no.id>
2003-07-17  2:23 ` Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast usage) kuznet
2003-07-17  2:23   ` David S. Miller
2003-07-17  8:38   ` Mika Liljeberg
2003-07-17  9:06     ` Anycast usage, final diagnosis? (was: IPv6: Fix broken anycast kuznet
2003-07-17  9:32       ` Mika Liljeberg

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