Hello!
This patch supports standard default source address selection
algorithm. It takes status, address/prefix itself (prefer same address,
prefer longest matching prefix) into consideration.
Note: Even though matching label is not implemented yet,
this is better than current one.
Following patch is against linux-2.4.19.
Thank you in advance.
-------------------------------------------------------------------
Patch-Name: Improvement of Source Address Selection
Patch-Id: FIX_2_4_19_SADDRSELECT-20020906
Patch-Author: YOSHIFUJI Hideaki / USAGI Project <yoshfuji@linux-ipv6.org>
Credit: YOSHIFUJI Hideaki / USAGI Project <yoshfuji@linux-ipv6.org>
Reference: draft-ietf-ipv6-default-addr-select-09.txt
-------------------------------------------------------------------
Index: include/net/addrconf.h
===================================================================
RCS file: /cvsroot/usagi/usagi-backport/linux24/include/net/addrconf.h,v
retrieving revision 1.1.1.1
retrieving revision 1.1.1.1.6.1
diff -u -r1.1.1.1 -r1.1.1.1.6.1
--- include/net/addrconf.h 2002/08/20 09:46:45 1.1.1.1
+++ include/net/addrconf.h 2002/09/26 19:15:15 1.1.1.1.6.1
@@ -55,6 +55,9 @@
struct net_device *dev);
extern struct inet6_ifaddr * ipv6_get_ifaddr(struct in6_addr *addr,
struct net_device *dev);
+extern int ipv6_dev_get_saddr(struct net_device *ddev,
+ struct in6_addr *daddr,
+ struct in6_addr *saddr);
extern int ipv6_get_saddr(struct dst_entry *dst,
struct in6_addr *daddr,
struct in6_addr *saddr);
Index: net/ipv6/addrconf.c
===================================================================
RCS file: /cvsroot/usagi/usagi-backport/linux24/net/ipv6/addrconf.c,v
retrieving revision 1.1.1.1
retrieving revision 1.1.1.1.6.4
diff -u -r1.1.1.1 -r1.1.1.1.6.4
--- net/ipv6/addrconf.c 2002/08/20 09:47:02 1.1.1.1
+++ net/ipv6/addrconf.c 2002/09/26 19:28:13 1.1.1.1.6.4
@@ -26,6 +26,10 @@
* packets.
* yoshfuji@USAGI : Fixed interval between DAD
* packets.
+ * YOSHIFUJI Hideaki @USAGI : improved source address
+ * selection; consider scope,
+ * status etc.
+ *
*/
#include <linux/config.h>
@@ -188,6 +192,99 @@
return IPV6_ADDR_RESERVED;
}
+#ifndef IPV6_ADDR_MC_SCOPE
+#define IPV6_ADDR_MC_SCOPE(a) \
+ ((a)->s6_addr[1] & 0x0f) /* XXX nonstandard */
+#define __IPV6_ADDR_SCOPE_RESERVED -2
+#define __IPV6_ADDR_SCOPE_ANY -1
+#define IPV6_ADDR_SCOPE_NODELOCAL 0x01
+#define IPV6_ADDR_SCOPE_LINKLOCAL 0x02
+#define IPV6_ADDR_SCOPE_SITELOCAL 0x05
+#define IPV6_ADDR_SCOPE_ORGLOCAL 0x08
+#define IPV6_ADDR_SCOPE_GLOBAL 0x0e
+#endif
+
+int ipv6_addrselect_scope(const struct in6_addr *addr)
+{
+ u32 st;
+
+ st = addr->s6_addr32[0];
+
+ if ((st & __constant_htonl(0xE0000000)) != __constant_htonl(0x00000000) &&
+ (st & __constant_htonl(0xE0000000)) != __constant_htonl(0xE0000000))
+ return IPV6_ADDR_SCOPE_GLOBAL;
+
+ if ((st & __constant_htonl(0xFF000000)) == __constant_htonl(0xFF000000))
+ return IPV6_ADDR_MC_SCOPE(addr);
+
+ if ((st & __constant_htonl(0xFFC00000)) == __constant_htonl(0xFE800000))
+ return IPV6_ADDR_SCOPE_LINKLOCAL;
+
+ if ((st & __constant_htonl(0xFFC00000)) == __constant_htonl(0xFEC00000))
+ return IPV6_ADDR_SCOPE_SITELOCAL;
+
+ if ((st | addr->s6_addr32[1]) == 0) {
+ if (addr->s6_addr32[2] == 0) {
+ if (addr->s6_addr32[3] == 0)
+ return __IPV6_ADDR_SCOPE_ANY;
+
+ if (addr->s6_addr32[3] == __constant_htonl(0x00000001))
+ return IPV6_ADDR_SCOPE_LINKLOCAL; /* section 2.4 */
+
+ return IPV6_ADDR_SCOPE_GLOBAL; /* section 2.3 */
+ }
+
+ if (addr->s6_addr32[2] == __constant_htonl(0x0000FFFF)) {
+ if (addr->s6_addr32[3] == __constant_htonl(0xA9FF0000))
+ return IPV6_ADDR_SCOPE_LINKLOCAL; /* section 2.2 */
+ if (addr->s6_addr32[3] == __constant_htonl(0xAC000000)) {
+ if (addr->s6_addr32[3] == __constant_htonl(0xAC100000))
+ return IPV6_ADDR_SCOPE_SITELOCAL; /* section 2.2 */
+
+ return IPV6_ADDR_SCOPE_LINKLOCAL; /* section 2.2 */
+ }
+ if (addr->s6_addr32[3] == __constant_htonl(0x0A000000))
+ return IPV6_ADDR_SCOPE_SITELOCAL; /* section 2.2 */
+ if (addr->s6_addr32[3] == __constant_htonl(0xC0A80000))
+ return IPV6_ADDR_SCOPE_SITELOCAL; /* section 2.2 */
+
+ return IPV6_ADDR_SCOPE_GLOBAL; /* section 2.2 */
+ }
+ }
+
+ return __IPV6_ADDR_SCOPE_RESERVED;
+}
+
+/* find 1st bit in difference between the 2 addrs */
+static inline int addr_diff(const void *__a1, const void *__a2, int addrlen)
+{
+ /* find 1st bit in difference between the 2 addrs.
+ * bit may be an invalid value,
+ * but if it is >= plen, the value is ignored in any case.
+ */
+ const u32 *a1 = __a1;
+ const u32 *a2 = __a2;
+ int i;
+
+ addrlen >>= 2;
+ for (i = 0; i < addrlen; i++) {
+ u32 xb = a1[i] ^ a2[i];
+ if (xb) {
+ int j = 31;
+ xb = ntohl(xb);
+ while ((xb & (1 << j)) == 0)
+ j--;
+ return (i * 32 + 31 - j);
+ }
+ }
+ return addrlen<<5;
+}
+
+static inline int ipv6_addr_diff(const struct in6_addr *a1, const struct in6_addr *a2)
+{
+ return addr_diff(a1->s6_addr, a2->s6_addr, sizeof(struct in6_addr));
+}
+
static void addrconf_del_timer(struct inet6_ifaddr *ifp)
{
if (del_timer(&ifp->timer))
@@ -449,120 +546,137 @@
/*
* Choose an apropriate source address
- * should do:
- * i) get an address with an apropriate scope
- * ii) see if there is a specific route for the destination and use
- * an address of the attached interface
- * iii) don't use deprecated addresses
+ * draft-ietf-ipngwg-default-addr-select-09.txt
*/
-int ipv6_get_saddr(struct dst_entry *dst,
- struct in6_addr *daddr, struct in6_addr *saddr)
+struct addrselect_attrs {
+ struct inet6_ifaddr *ifp;
+ int match;
+ int deprecated;
+ int home;
+ int temporary;
+ int device;
+ int scope;
+ int label;
+ int matchlen;
+};
+
+int ipv6_dev_get_saddr(struct net_device *daddr_dev,
+ struct in6_addr *daddr, struct in6_addr *saddr)
{
- int scope;
- struct inet6_ifaddr *ifp = NULL;
- struct inet6_ifaddr *match = NULL;
- struct net_device *dev = NULL;
+ int daddr_scope;
+ struct inet6_ifaddr *ifp0, *ifp = NULL;
+ struct net_device *dev;
struct inet6_dev *idev;
- struct rt6_info *rt;
- int err;
- rt = (struct rt6_info *) dst;
- if (rt)
- dev = rt->rt6i_dev;
-
- scope = ipv6_addr_scope(daddr);
- if (rt && (rt->rt6i_flags & RTF_ALLONLINK)) {
- /*
- * route for the "all destinations on link" rule
- * when no routers are present
- */
- scope = IFA_LINK;
- }
-
- /*
- * known dev
- * search dev and walk through dev addresses
- */
+ int err;
+ int update;
+ struct addrselect_attrs candidate = {NULL,0,0,0,0,0,0,0,0};
- if (dev) {
- if (dev->flags & IFF_LOOPBACK)
- scope = IFA_HOST;
+ daddr_scope = ipv6_addrselect_scope(daddr);
- read_lock(&addrconf_lock);
+ read_lock(&dev_base_lock);
+ read_lock(&addrconf_lock);
+ for (dev = dev_base; dev; dev=dev->next) {
idev = __in6_dev_get(dev);
- if (idev) {
- read_lock_bh(&idev->lock);
- for (ifp=idev->addr_list; ifp; ifp=ifp->if_next) {
- if (ifp->scope == scope) {
- if (!(ifp->flags & (IFA_F_DEPRECATED|IFA_F_TENTATIVE))) {
- in6_ifa_hold(ifp);
- read_unlock_bh(&idev->lock);
- read_unlock(&addrconf_lock);
- goto out;
- }
-
- if (!match && !(ifp->flags & IFA_F_TENTATIVE)) {
- match = ifp;
- in6_ifa_hold(ifp);
- }
+
+ if (!idev)
+ continue;
+
+ read_lock_bh(&idev->lock);
+ ifp0 = idev->addr_list;
+ for (ifp=ifp0; ifp; ifp=ifp->if_next) {
+ struct addrselect_attrs temp = {NULL,0,0,0,0,0,0,0,0};
+ update = 0;
+
+ /* Rule 1: Prefer same address */
+ temp.match = ipv6_addr_cmp(&ifp->addr, daddr) == 0;
+ if (!update)
+ update = temp.match - candidate.match;
+ if (update < 0) {
+ continue;
+ }
+
+ /* Rule 2: Prefer appropriate scope */
+ temp.scope = ipv6_addrselect_scope(&ifp->addr);
+ if (!update) {
+ update = temp.scope - candidate.scope;
+ if (update > 0) {
+ update = candidate.scope < daddr_scope ? 1 : -1;
+ } else if (update < 0) {
+ update = temp.scope < daddr_scope ? -1 : 1;
}
}
- read_unlock_bh(&idev->lock);
- }
- read_unlock(&addrconf_lock);
- }
+ if (update < 0) {
+ continue;
+ }
- if (scope == IFA_LINK)
- goto out;
+ /* Rule 3: Avoid deprecated address */
+ temp.deprecated = ifp->flags & IFA_F_DEPRECATED;
+ if (!update)
+ update = candidate.deprecated - temp.deprecated;
+ if (update < 0) {
+ continue;
+ }
- /*
- * dev == NULL or search failed for specified dev
- */
+ /* XXX: Rule 4: Prefer home address */
- read_lock(&dev_base_lock);
- read_lock(&addrconf_lock);
- for (dev = dev_base; dev; dev=dev->next) {
- idev = __in6_dev_get(dev);
- if (idev) {
- read_lock_bh(&idev->lock);
- for (ifp=idev->addr_list; ifp; ifp=ifp->if_next) {
- if (ifp->scope == scope) {
- if (!(ifp->flags&(IFA_F_DEPRECATED|IFA_F_TENTATIVE))) {
- in6_ifa_hold(ifp);
- read_unlock_bh(&idev->lock);
- goto out_unlock_base;
- }
-
- if (!match && !(ifp->flags&IFA_F_TENTATIVE)) {
- match = ifp;
- in6_ifa_hold(ifp);
- }
- }
+ /* Rule 5: Prefer outgoing interface */
+ temp.device = daddr_dev ? daddr_dev == (ifp->idev ? ifp->idev->dev : daddr_dev) : 0;
+ if (!update)
+ update = temp.device - candidate.device;
+ if (update < 0) {
+ continue;
+ }
+
+ /* XXX: Rule 6: Prefer matching label */
+ temp.label = 0;
+ if (!update)
+ update = temp.label - candidate.label;
+ if (update < 0) {
+ continue;
}
- read_unlock_bh(&idev->lock);
+
+ /* XXX: Rule 7: Prefer public address */
+
+ /* Rule 8: Use longest matching prefix */
+ temp.matchlen = ipv6_addr_diff(&ifp->addr, daddr);
+ if (!update)
+ update = temp.matchlen - candidate.matchlen;
+ if (update < 0) {
+ continue;
+ }
+
+ /* Final Rule */
+ if (update <= 0)
+ continue;
+
+ /* update candidate */
+ temp.ifp = ifp;
+ in6_ifa_hold(ifp);
+ if (candidate.ifp)
+ in6_ifa_put(candidate.ifp);
+ candidate = temp;
}
+ read_unlock_bh(&idev->lock);
}
-
-out_unlock_base:
read_unlock(&addrconf_lock);
read_unlock(&dev_base_lock);
-
-out:
- if (ifp == NULL) {
- ifp = match;
- match = NULL;
- }
- err = -EADDRNOTAVAIL;
- if (ifp) {
- ipv6_addr_copy(saddr, &ifp->addr);
+ if (candidate.ifp) {
+ ipv6_addr_copy(saddr, &candidate.ifp->addr);
+ in6_ifa_put(candidate.ifp);
err = 0;
- in6_ifa_put(ifp);
+ } else {
+ err = -EADDRNOTAVAIL;
}
- if (match)
- in6_ifa_put(match);
-
return err;
+}
+
+int ipv6_get_saddr(struct dst_entry *dst,
+ struct in6_addr *daddr, struct in6_addr *saddr)
+{
+ return ipv6_dev_get_saddr(dst ? ((struct rt6_info *)dst)->rt6i_dev : NULL,
+ daddr, saddr);
}
int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr)
-
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This archive was generated by hypermail 2b29 : Mon Sep 30 2002 - 22:00:31 EST