[PATCH] Prefix List patch against 2.5.70

[Krishna Kumar <krkumar@us.ibm.com>]

Hi all,

Following is a modified patch to implement Prefix List in IPv6. This has the
following changes from the patch submitted previously :

- Added user interface to retrieve the prefix list and other RA parameters for
   DHVPv6 (http://sourceforge.net/projects/dhcpv6). Also incorporated Yoshifuji’s
   suggestion to change the user interface to use rtnetlink instead of /proc (I
   have kept an OPTIONAL extra user interface which is provided as a file in
   /proc/net, but that code can be removed - it is clearly marked as OPTIONAL). I
   am not an expert in netlink code, so please excuse me if I have committed any
   blunders.
- Changed to support different parameters of a RA (flags, lifetime, address of
   the router, etc.

Alexey had originally asked why I am not using fib to store the prefix list, and
the reasons for the way this is designed as part of the dev are :

- To be a prefix list entry, it should come via an RA. So a manual ifconfig
   <address> should not cause a prefix entry to be created. This can however be
   avoided by adding more code to determine if this is an RA added routing entry
   or a manual one. However, a routing table is per destination, while the Prefix
   List is conceptualized as being per interface.

- Routing table will have lots of address prefixes that are not configured to
   the local interface. Eg, none of the interfaces might have the address
   2002::2, but a route entry can exist for this; or I can add a route myself and
   should not expect to see the prefix of this route in the Prefix List. More
   code (flags) needs to be present to parse each entry in this case. Eg, for
   each routing entry, you need to make sure it is the same device, that it is
   not a Link Local destination, and there is no 'next hop' field.

- Also, when the user requests the Prefix List, the search over a longer routing
   table across all radix tree nodes is more time consuming since there is no key
   to use for the lookup (you have to always walk the entire tree). I think it
   would be faster in the case where the routing table is very large, and there
   aren't too many interfaces. The difference is that in case of routing table
   lookup, you go through the entire tree and parse each entry, while in the
   proposed approach, the linear search is only done to locate the 'dev' and then
   the work is more straightforward –  return all entries.

The implementation is done by adding the prefix on receipt of a RA (or update
the prefix) to the list of prefixes off the inet6_dev structure (along with
addr_list, mc_list, ac_list, etc). This also has a new spinlock in the structure
so that the idev->lock need not be held in writer mode on every RA, rather the
spinlock is held.

Following is the patch against 2.5.70 (I have created against 2.4.20 also, but
am holding off on that).

Thanks,

- KK

diff -ruN linux-2.5.70.org/include/linux/icmpv6.h 
linux-2.5.70/include/linux/icmpv6.h
--- linux-2.5.70.org/include/linux/icmpv6.h	2003-05-26 18:00:26.000000000 -0700
+++ linux-2.5.70/include/linux/icmpv6.h	2003-05-30 15:14:46.000000000 -0700
@@ -122,6 +122,12 @@
  #define ICMPV6_UNK_OPTION		2

  /*
+ *	Bit flags of the RA
+ */
+#define ND_RA_FLAG_MANAGED		0x80
+#define ND_RA_FLAG_OTHER		0x40
+
+/*
   *	constants for (set|get)sockopt
   */

diff -ruN linux-2.5.70.org/include/linux/rtnetlink.h 
linux-2.5.70/include/linux/rtnetlink.h
--- linux-2.5.70.org/include/linux/rtnetlink.h	2003-05-26 18:00:46.000000000 -0700
+++ linux-2.5.70/include/linux/rtnetlink.h	2003-05-30 15:14:46.000000000 -0700
@@ -47,7 +47,9 @@
  #define	RTM_DELTFILTER	(RTM_BASE+29)
  #define	RTM_GETTFILTER	(RTM_BASE+30)

-#define	RTM_MAX		(RTM_BASE+31)
+#define	RTM_GETPLIST	(RTM_BASE+34)
+
+#define	RTM_MAX		(RTM_BASE+35)

  /*
     Generic structure for encapsulation optional route information.
diff -ruN linux-2.5.70.org/include/net/addrconf.h 
linux-2.5.70/include/net/addrconf.h
--- linux-2.5.70.org/include/net/addrconf.h	2003-05-26 18:00:46.000000000 -0700
+++ linux-2.5.70/include/net/addrconf.h	2003-05-30 15:16:29.000000000 -0700
@@ -45,6 +45,29 @@

  #define IN6_ADDR_HSIZE		16

+/* An element of the prefix list, which is added to idev->prefix_list */
+struct prefix_element {
+	struct list_head list;		/* linkage member for this entry */
+	struct prefix_info pinfo;	/* actual prefix information */
+	unsigned long timestamp;	/* jiffies when RA was received */
+	unsigned int ra_flags;		/* bit-flags contained in the RA */
+	struct in6_addr ra_addr;	/* router's address */
+};
+
+/* prefix list returned to user space in this structure */
+struct plist_user_info {
+	char name[IFNAMSIZ];		/* interface name */
+	int ifindex;			/* interface index */
+	int nprefixes;			/* number of elements in 'prefix' */
+	struct var_plist_user_info {	/* multiple elements */
+		char flags[3];		/* router advertised flags */
+		int plen;		/* prefix length */
+		__u32 valid;		/* valid lifetime */
+		struct in6_addr ra_addr;/* advertising router */
+		struct in6_addr prefix;	/* prefix */
+	} plist_vars[0];
+};
+
  extern void			addrconf_init(void);
  extern void			addrconf_cleanup(void);

@@ -95,7 +118,8 @@
  extern int ipv6_chk_mcast_addr(struct net_device *dev, struct in6_addr *group,
  		struct in6_addr *src_addr);

-extern void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len);
+extern void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len,
+		struct in6_addr *ra_addr, struct ra_msg *ra);

  /*
   *	anycast prototypes (anycast.c)
diff -ruN linux-2.5.70.org/include/net/if_inet6.h 
linux-2.5.70/include/net/if_inet6.h
--- linux-2.5.70.org/include/net/if_inet6.h	2003-05-26 18:00:59.000000000 -0700
+++ linux-2.5.70/include/net/if_inet6.h	2003-05-30 15:17:59.000000000 -0700
@@ -176,6 +176,12 @@
  	struct timer_list	mc_gq_timer;	/* general query timer */
  	struct timer_list	mc_ifc_timer;	/* interface change timer */

+#ifdef CONFIG_IPV6_PREFIXLIST
+	struct list_head	prefix_list;
+	spinlock_t		prefix_lock;
+	int			prefix_count;	/* number of prefixes */
+#endif
+
  	struct ifacaddr6	*ac_list;
  	rwlock_t		lock;
  	atomic_t		refcnt;
diff -ruN linux-2.5.70.org/net/ipv6/Kconfig linux-2.5.70/net/ipv6/Kconfig
--- linux-2.5.70.org/net/ipv6/Kconfig	2003-05-26 18:00:40.000000000 -0700
+++ linux-2.5.70/net/ipv6/Kconfig	2003-05-30 17:58:10.000000000 -0700
@@ -42,4 +42,13 @@

  	  If unsure, say Y.

+config IPV6_PREFIXLIST
+	bool "IPv6: Prefix List"
+	depends on IPV6
+	---help---
+	  For applications needing to retrieve the list of prefixes supported
+	  on the system. Defined in RFC2461.
+
+	  If unsure, say Y.
+
  source "net/ipv6/netfilter/Kconfig"
diff -ruN linux-2.5.70.org/net/ipv6/addrconf.c linux-2.5.70/net/ipv6/addrconf.c
--- linux-2.5.70.org/net/ipv6/addrconf.c	2003-05-26 18:00:58.000000000 -0700
+++ linux-2.5.70/net/ipv6/addrconf.c	2003-05-30 17:55:31.000000000 -0700
@@ -67,6 +67,7 @@
  #include <net/ip.h>
  #include <linux/if_tunnel.h>
  #include <linux/rtnetlink.h>
+#include <linux/inet.h>

  #ifdef CONFIG_IPV6_PRIVACY
  #include <linux/random.h>
@@ -87,6 +88,8 @@
  #define ADBG(x)
  #endif

+#define INFINITE	0xffffffff
+
  #ifdef CONFIG_SYSCTL
  static void addrconf_sysctl_register(struct inet6_dev *idev, struct 
ipv6_devconf *p);
  static void addrconf_sysctl_unregister(struct ipv6_devconf *p);
@@ -292,6 +295,9 @@
  	struct net_device *dev = idev->dev;
  	BUG_TRAP(idev->addr_list==NULL);
  	BUG_TRAP(idev->mc_list==NULL);
+#ifdef CONFIG_IPV6_PREFIXLIST
+	BUG_TRAP(list_empty(&idev->prefix_list) == 1);
+#endif
  #ifdef NET_REFCNT_DEBUG
  	printk(KERN_DEBUG "in6_dev_finish_destroy: %s\n", dev ? dev->name : "NIL");
  #endif
@@ -319,6 +325,10 @@
  	if (ndev) {
  		memset(ndev, 0, sizeof(struct inet6_dev));

+#ifdef CONFIG_IPV6_PREFIXLIST
+		INIT_LIST_HEAD(&ndev->prefix_list);
+		ndev->prefix_lock = SPIN_LOCK_UNLOCKED;
+#endif
  		ndev->lock = RW_LOCK_UNLOCKED;
  		ndev->dev = dev;
  		memcpy(&ndev->cnf, &ipv6_devconf_dflt, sizeof(ndev->cnf));
@@ -746,6 +756,321 @@
  }
  #endif

+#ifdef CONFIG_IPV6_PREFIXLIST
+
+/* Adds a prefix to the list of prefixes on this interface */
+static int ipv6_add_prefix(struct inet6_dev *idev, struct prefix_info *pinfo,
+                __u32 lifetime, struct in6_addr *ra_addr, struct ra_msg *ra)
+{
+	int ifindex;
+	struct in6_addr	prefix;
+	struct list_head *head;
+	struct prefix_element *p;
+
+	ipv6_addr_prefix(&prefix, &pinfo->prefix, pinfo->prefix_len);
+
+	/* Check if the prefix exists in our list */
+
+	read_lock_bh(&idev->lock);
+	spin_lock_bh(&idev->prefix_lock);
+	ifindex = idev->dev->ifindex;
+	list_for_each(head, &idev->prefix_list) {
+		p = list_entry(head, struct prefix_element, list);
+		if (p->pinfo.prefix_len == pinfo->prefix_len
+		    && ipv6_addr_cmp(&p->pinfo.prefix, &prefix) == 0) {
+			/* Existing Prefix, modify it with new values */
+			p->pinfo.valid = lifetime;
+			p->timestamp = jiffies;
+			ipv6_addr_copy(&p->ra_addr, ra_addr);
+			p->ra_flags = 0; /* overwrite prev value */
+			if (ra->icmph.icmp6_addrconf_managed)
+				p->ra_flags |= ND_RA_FLAG_MANAGED;
+			if (ra->icmph.icmp6_addrconf_other)
+				p->ra_flags |= ND_RA_FLAG_OTHER;
+			spin_unlock_bh(&idev->prefix_lock);
+			read_unlock_bh(&idev->lock);
+			return 0;
+		}
+	}
+
+	/* New Prefix, allocate one and fill in */
+	if ((p = kmalloc(sizeof(struct prefix_element), GFP_ATOMIC)) == NULL) {
+		ADBG(("ipv6_add_prefix: malloc failed\n"));
+		spin_unlock_bh(&idev->prefix_lock);
+		read_unlock_bh(&idev->lock);
+		return -1;
+	}
+	memset(p, 0, sizeof(*p));
+	INIT_LIST_HEAD(&p->list);
+	p->pinfo.valid = lifetime;
+	p->timestamp = jiffies;
+	p->pinfo.prefix_len = pinfo->prefix_len;
+	ipv6_addr_copy(&p->pinfo.prefix, &prefix);
+	ipv6_addr_copy(&p->ra_addr, ra_addr);
+	if (ra->icmph.icmp6_addrconf_managed)
+		p->ra_flags = ND_RA_FLAG_MANAGED;
+	if (ra->icmph.icmp6_addrconf_other)
+		p->ra_flags |= ND_RA_FLAG_OTHER;
+
+	list_add(&p->list, idev->prefix_list.prev);	/* add to end of list */
+	idev->prefix_count++;
+	spin_unlock_bh(&idev->prefix_lock);
+	read_unlock_bh(&idev->lock);
+	return 0;
+}
+
+/* Kernel level interface to the prefix list */
+int ipv6_get_prefix_entries(struct prefix_info **plist, int ifindex, int plen)
+{
+	int count;
+	struct net_device *dev;
+	struct inet6_dev *idev;
+	struct list_head *head;
+	struct prefix_element *p;
+
+	if (plist == NULL) {
+		BUG_TRAP(plist != NULL);
+		return -EINVAL;
+	}
+	if ((dev = dev_get_by_index(ifindex)) == NULL) {
+		printk(KERN_WARNING "Bad I/F (%d) in ipv6_get_prefix_entries\n",
+		       ifindex);
+		return -EINVAL;
+	}
+
+	if ((idev = __in6_dev_get(dev)) == NULL) {
+		dev_put(dev);
+		return -EINVAL;
+	}
+
+	read_lock_bh(&idev->lock);
+	if (!(count = idev->prefix_count)) {
+		/* No elements on list */
+		goto out;
+	}
+	if ((*plist = kmalloc(count * sizeof(struct prefix_info),
+			      GFP_ATOMIC)) == NULL) {
+		count = -ENOMEM;
+		goto out;
+	}
+	count = 0;
+	spin_lock_bh(&idev->prefix_lock);
+	list_for_each(head, &idev->prefix_list) {
+		p = list_entry(head, struct prefix_element, list);
+		if (plen == 0 || p->pinfo.prefix_len == plen) {
+			memcpy(*plist + count, &p->pinfo,
+			       sizeof(struct prefix_info));
+			count++;
+		}
+	}
+	spin_unlock_bh(&idev->prefix_lock);
+ out:
+	read_unlock_bh(&idev->lock);
+	dev_put(dev);
+	return count;
+}
+
+/* User level interface to the prefix list */
+int prefix_list_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	/* variables for manipulating prefix_list */
+	int i, nprefixes, count;
+	struct net_device *dev;
+	struct inet6_dev *idev;
+	struct list_head *head;
+	struct prefix_element *p_el;
+
+	/* variables for manipulating netlink */
+	int type = cb->nlh->nlmsg_type;
+	struct nlmsghdr  *nlh;
+	struct plist_user_info *pinfo;
+	unsigned char *b = skb->tail, *org_tail = skb->tail;
+
+	read_lock(&dev_base_lock);
+	for (dev = dev_base; dev; dev = dev->next) {
+		if (!(idev = __in6_dev_get(dev)))
+			continue;
+		read_lock_bh(&idev->lock);
+		if (!(nprefixes = idev->prefix_count)) {
+			read_unlock_bh(&idev->lock);
+			continue;
+		}
+		nlh = NLMSG_PUT(skb, NETLINK_CB(cb->skb).pid,
+				cb->nlh->nlmsg_seq, type, sizeof(*pinfo) +
+				nprefixes * sizeof(struct var_plist_user_info));
+		pinfo = NLMSG_DATA(nlh);
+		count = 0;
+		spin_lock_bh(&idev->prefix_lock);
+		list_for_each(head, &idev->prefix_list) {
+			p_el = list_entry(head, struct prefix_element, list);
+			if (!count) {	/* store stuff first time */
+				strcpy(pinfo->name, dev->name);
+				pinfo->ifindex = dev->ifindex;
+			}
+			pinfo->plist_vars[count].plen = p_el->pinfo.prefix_len;
+			pinfo->plist_vars[count].valid = p_el->pinfo.valid -
+				(jiffies - p_el->timestamp)/HZ;
+			if ((p_el->ra_flags & (ND_RA_FLAG_MANAGED |
+			    ND_RA_FLAG_OTHER))
+			    == (ND_RA_FLAG_MANAGED|ND_RA_FLAG_OTHER))
+				strcpy(pinfo->plist_vars[count].flags, "MO");
+			else if (p_el->ra_flags & ND_RA_FLAG_MANAGED)
+				strcpy(pinfo->plist_vars[count].flags, "M");
+			else if (p_el->ra_flags & ND_RA_FLAG_OTHER)
+				strcpy(pinfo->plist_vars[count].flags, "O");
+			else
+				strcpy(pinfo->plist_vars[count].flags, "-");
+			ipv6_addr_copy(&pinfo->plist_vars[count].ra_addr,
+			    &p_el->ra_addr);
+			for (i = 0; i < 8; i++)
+				pinfo->plist_vars[count].ra_addr.s6_addr16[i] =
+				    __constant_ntohs(pinfo->plist_vars[count].ra_addr.s6_addr16[i]);
+			ipv6_addr_copy(&pinfo->plist_vars[count].prefix,
+			    &p_el->pinfo.prefix);
+			for (i = 0; i < p_el->pinfo.prefix_len/16; i++)
+				pinfo->plist_vars[count].prefix.s6_addr16[i] =
+				    __constant_ntohs(pinfo->plist_vars[count].prefix.s6_addr16[i]);
+			count++;
+		}
+		spin_unlock_bh(&idev->prefix_lock);
+		read_unlock_bh(&idev->lock);
+		BUG_TRAP(nprefixes == count);
+		pinfo->nprefixes = count;
+		nlh->nlmsg_len = skb->tail - org_tail;
+		org_tail = skb->tail;
+	}
+	read_unlock(&dev_base_lock);
+	return skb->len;
+
+nlmsg_failure :
+	read_unlock_bh(&idev->lock);
+	read_unlock(&dev_base_lock);
+	skb_trim(skb, b - skb->data);
+        return -1;
+}
+
+/* Expire prefixes from the idev list periodically */
+static void ipv6_expire_prefixes(void)
+{
+	unsigned long		now = jiffies;
+	struct net_device	*dev;
+	struct inet6_dev	*idev;
+	struct list_head	*head, *next;
+	struct prefix_element	*p;
+	unsigned long		age;
+
+	read_lock(&dev_base_lock);
+	for (dev = dev_base; dev; dev = dev->next) {
+		if (!(idev = __in6_dev_get(dev))) {
+			continue;
+		}
+		read_lock_bh(&idev->lock);
+		if (!idev->prefix_count) {
+			read_unlock_bh(&idev->lock);
+			continue;
+		}
+		spin_lock_bh(&idev->prefix_lock);
+		list_for_each_safe(head, next, &idev->prefix_list) {
+			p = list_entry(head, struct prefix_element, list);
+			if (p->pinfo.valid != INFINITE) {
+				age = (now - p->timestamp) / HZ;
+				if (age > p->pinfo.valid) {
+					idev->prefix_count--;
+					list_del(&p->list);
+					kfree(p);
+				}
+			}
+		}
+		spin_unlock_bh(&idev->prefix_lock);
+		read_unlock_bh(&idev->lock);
+	}
+	read_unlock(&dev_base_lock);
+}
+
+#ifdef CONFIG_PROC_FS
+
+/* OPTIONAL alternate interface to prefix list via /proc filesystem */
+static int prefix_list_proc_dump(char *buffer, char **start, off_t offset,
+			   int length)
+{
+	int i;
+	int len = 0;
+	off_t pos=0;
+	off_t begin=0;
+
+	struct net_device *dev;
+	struct inet6_dev *idev;
+	struct list_head *head;
+	struct prefix_element *p;
+
+	read_lock(&dev_base_lock);
+	for (dev = dev_base; dev; dev = dev->next) {
+		if (!(idev = __in6_dev_get(dev))) {
+			continue;
+		}
+		read_lock_bh(&idev->lock);
+		spin_lock_bh(&idev->prefix_lock);
+		if (list_empty(&idev->prefix_list)) {
+			spin_unlock_bh(&idev->prefix_lock);
+			read_unlock_bh(&idev->lock);
+			continue;
+		}
+		list_for_each(head, &idev->prefix_list) {
+			p = list_entry(head, struct prefix_element, list);
+			len += sprintf(buffer + len, "%-6s %-4d %-4d",
+				dev->name, dev->ifindex, p->pinfo.prefix_len);
+			if ((p->ra_flags & (ND_RA_FLAG_MANAGED |
+			    ND_RA_FLAG_OTHER))
+			    == (ND_RA_FLAG_MANAGED|ND_RA_FLAG_OTHER))
+				len += sprintf(buffer + len, "%-4s", "MO");
+			else if (p->ra_flags & ND_RA_FLAG_MANAGED)
+				len += sprintf(buffer + len, "%-4s", "M");
+			else if (p->ra_flags & ND_RA_FLAG_OTHER)
+				len += sprintf(buffer + len, "%-4s", "O");
+			else
+				len += sprintf(buffer + len, "%-4s", "-");
+			for (i = 0; i < p->pinfo.prefix_len / 8; i++) {
+				sprintf(buffer + len, "%02x",
+					p->pinfo.prefix.s6_addr[i]);
+				len += 2;
+			}
+			len += sprintf(buffer + len, "%-4s", " ");
+			for (i = 0; i < 16; i++) {
+				sprintf(buffer + len, "%02x",
+					p->ra_addr.s6_addr[i]);
+				len += 2;
+			}
+			len += sprintf(buffer + len, "\n");
+			pos=begin+len;
+			if(pos<offset) {
+				len=0;
+				begin=pos;
+			}
+			if(pos>offset+length) {
+				spin_unlock_bh(&idev->prefix_lock);
+				read_unlock_bh(&idev->lock);
+				goto done;
+			}
+		}
+		spin_unlock_bh(&idev->prefix_lock);
+		read_unlock_bh(&idev->lock);
+	}
+done:
+	read_unlock(&dev_base_lock);
+
+	*start=buffer+(offset-begin);
+	len-=(offset-begin);
+	if(len>length)
+		len=length;
+	if(len<0)
+		len=0;
+	return len;
+}
+
+#endif	/* CONFIG_PROC_FS */
+
+#endif	/* CONFIG_IPV6_PREFIXLIST */
+
  /*
   *	Choose an appropriate source address
   *	should do:
@@ -1281,7 +1606,8 @@
  	return idev;
  }

-void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len)
+void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len,
+	struct in6_addr *ra_addr, struct ra_msg *ra)
  {
  	struct prefix_info *pinfo;
  	struct rt6_info *rt;
@@ -1355,6 +1681,12 @@
  		addrconf_prefix_route(&pinfo->prefix, pinfo->prefix_len,
  				      dev, rt_expires, RTF_ADDRCONF|RTF_EXPIRES);
  	}
+#ifdef CONFIG_IPV6_PREFIXLIST
+	if (pinfo->onlink && valid_lft)
+		/* Add this prefix to the list of prefixes on this interface */
+		ipv6_add_prefix(in6_dev, pinfo, valid_lft, ra_addr, ra);
+#endif
+
  	if (rt)
  		dst_release(&rt->u.dst);

@@ -1851,6 +2183,10 @@
  	struct inet6_dev *idev;
  	struct inet6_ifaddr *ifa, **bifa;
  	int i;
+#ifdef CONFIG_IPV6_PREFIXLIST
+	struct list_head	*head, *next;
+	struct prefix_element	*p;
+#endif

  	ASSERT_RTNL();

@@ -1913,6 +2249,17 @@
  	else
  		ipv6_mc_down(idev);

+#ifdef CONFIG_IPV6_PREFIXLIST
+	/* Step 5: Free up Prefix List */
+	spin_lock_bh(&idev->prefix_lock);
+	list_for_each_safe(head, next, &idev->prefix_list) {
+		p = list_entry(head, struct prefix_element, list);
+		kfree(p);
+	}
+	INIT_LIST_HEAD(&idev->prefix_list);
+	spin_unlock_bh(&idev->prefix_lock);
+#endif
+
  	/* Shot the device (if unregistered) */

  	if (how == 1) {
@@ -2141,6 +2488,7 @@
  	return len;
  }

+
  #endif	/* CONFIG_PROC_FS */

  /*
@@ -2241,6 +2589,15 @@
  		write_unlock(&addrconf_hash_lock);
  	}

+#ifdef CONFIG_IPV6_PREFIXLIST
+	/*
+	 * We need to expire prefixes even if no addresses are deleted in the
+	 * loop above, since autoconfiguration may not be set in all router
+	 * advertisements.
+	 */
+	ipv6_expire_prefixes();
+#endif
+
  	addr_chk_timer.expires = time_before(next, jiffies + HZ) ? jiffies + HZ : next;
  	add_timer(&addr_chk_timer);
  	spin_unlock_bh(&addrconf_verify_lock);
@@ -2692,6 +3049,10 @@

  void __init addrconf_init(void)
  {
+#ifdef CONFIG_IPV6_PREFIXLIST
+	struct rtnetlink_link *link_p;
+#endif
+
  #ifdef MODULE
  	struct net_device *dev;
  #endif
@@ -2730,7 +3091,16 @@
  #ifdef CONFIG_PROC_FS
  	proc_net_create("if_inet6", 0, iface_proc_info);
  #endif
-	
+
+#ifdef CONFIG_IPV6_PREFIXLIST
+	if ((link_p = rtnetlink_links[PF_UNSPEC]) != NULL) /* PF_INET6 ? */
+		link_p[RTM_GETPLIST - RTM_BASE].dumpit = prefix_list_dump;
+#ifdef CONFIG_PROC_FS
+	/* OPTIONAL alternate interface to prefix list via /proc filesystem */
+	proc_net_create("ra6", 0, prefix_list_proc_dump);
+#endif
+#endif
+
  	addrconf_verify(0);
  	rtnetlink_links[PF_INET6] = inet6_rtnetlink_table;
  #ifdef CONFIG_SYSCTL
@@ -2798,6 +3168,9 @@

  #ifdef CONFIG_PROC_FS
  	proc_net_remove("if_inet6");
+#ifdef CONFIG_IPV6_PREFIXLIST
+	proc_net_remove("ra6");
+#endif
  #endif
  }
  #endif	/* MODULE */
diff -ruN linux-2.5.70.org/net/ipv6/ndisc.c linux-2.5.70/net/ipv6/ndisc.c
--- linux-2.5.70.org/net/ipv6/ndisc.c	2003-05-26 18:00:41.000000000 -0700
+++ linux-2.5.70/net/ipv6/ndisc.c	2003-05-30 15:14:46.000000000 -0700
@@ -1146,7 +1146,8 @@
  		for (p = ndopts.nd_opts_pi;
  		     p;
  		     p = ndisc_next_option(p, ndopts.nd_opts_pi_end)) {
-			addrconf_prefix_rcv(skb->dev, (u8*)p, (p->nd_opt_len) << 3);
+			addrconf_prefix_rcv(skb->dev, (u8*)p,
+			   (p->nd_opt_len) << 3, &skb->nh.ipv6h->saddr, ra_msg);
  		}
  	}