[IPV6]: RFC3484 compliant source address selection
Choose more appropriate source address; e.g.
- outgoing interface
- non-deprecated
- scope
- matching label
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index ff895da..a34d150 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -809,138 +809,274 @@
#endif
/*
- * Choose an appropriate source address
- * should do:
- * i) get an address with an appropriate 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
+ * Choose an appropriate source address (RFC3484)
*/
-static int inline ipv6_saddr_pref(const struct inet6_ifaddr *ifp, u8 invpref)
+struct ipv6_saddr_score {
+ int addr_type;
+ unsigned int attrs;
+ int matchlen;
+ unsigned int scope;
+ unsigned int rule;
+};
+
+#define IPV6_SADDR_SCORE_LOCAL 0x0001
+#define IPV6_SADDR_SCORE_PREFERRED 0x0004
+#define IPV6_SADDR_SCORE_HOA 0x0008
+#define IPV6_SADDR_SCORE_OIF 0x0010
+#define IPV6_SADDR_SCORE_LABEL 0x0020
+#define IPV6_SADDR_SCORE_PRIVACY 0x0040
+
+static int inline ipv6_saddr_preferred(int type)
{
- int pref;
- pref = ifp->flags&IFA_F_DEPRECATED ? 0 : 2;
-#ifdef CONFIG_IPV6_PRIVACY
- pref |= (ifp->flags^invpref)&IFA_F_TEMPORARY ? 0 : 1;
-#endif
- return pref;
+ if (type & (IPV6_ADDR_MAPPED|IPV6_ADDR_COMPATv4|
+ IPV6_ADDR_LOOPBACK|IPV6_ADDR_RESERVED))
+ return 1;
+ return 0;
}
-#ifdef CONFIG_IPV6_PRIVACY
-#define IPV6_GET_SADDR_MAXSCORE(score) ((score) == 3)
-#else
-#define IPV6_GET_SADDR_MAXSCORE(score) (score)
-#endif
+/* static matching label */
+static int inline ipv6_saddr_label(const struct in6_addr *addr, int type)
+{
+ /*
+ * prefix (longest match) label
+ * -----------------------------
+ * ::1/128 0
+ * ::/0 1
+ * 2002::/16 2
+ * ::/96 3
+ * ::ffff:0:0/96 4
+ */
+ if (type & IPV6_ADDR_LOOPBACK)
+ return 0;
+ else if (type & IPV6_ADDR_COMPATv4)
+ return 3;
+ else if (type & IPV6_ADDR_MAPPED)
+ return 4;
+ else if (addr->s6_addr16[0] == htons(0x2002))
+ return 2;
+ return 1;
+}
-int ipv6_dev_get_saddr(struct net_device *dev,
+int ipv6_dev_get_saddr(struct net_device *daddr_dev,
struct in6_addr *daddr, struct in6_addr *saddr)
{
- struct inet6_ifaddr *ifp = NULL;
- struct inet6_ifaddr *match = NULL;
- struct inet6_dev *idev;
- int scope;
- int err;
- int hiscore = -1, score;
+ struct ipv6_saddr_score hiscore;
+ struct inet6_ifaddr *ifa_result = NULL;
+ int daddr_type = __ipv6_addr_type(daddr);
+ int daddr_scope = __ipv6_addr_src_scope(daddr_type);
+ u32 daddr_label = ipv6_saddr_label(daddr, daddr_type);
+ struct net_device *dev;
- scope = ipv6_addr_scope(daddr);
-
- /*
- * known dev
- * search dev and walk through dev addresses
- */
-
- if (dev) {
- if (dev->flags & IFF_LOOPBACK)
- scope = IFA_HOST;
-
- read_lock(&addrconf_lock);
- 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_TENTATIVE)
- continue;
-#ifdef CONFIG_IPV6_PRIVACY
- score = ipv6_saddr_pref(ifp, idev->cnf.use_tempaddr > 1 ? IFA_F_TEMPORARY : 0);
-#else
- score = ipv6_saddr_pref(ifp, 0);
-#endif
- if (score <= hiscore)
- continue;
-
- if (match)
- in6_ifa_put(match);
- match = ifp;
- hiscore = score;
- in6_ifa_hold(ifp);
-
- if (IPV6_GET_SADDR_MAXSCORE(score)) {
- read_unlock_bh(&idev->lock);
- read_unlock(&addrconf_lock);
- goto out;
- }
- }
- }
- read_unlock_bh(&idev->lock);
- }
- read_unlock(&addrconf_lock);
- }
-
- if (scope == IFA_LINK)
- goto out;
-
- /*
- * dev == NULL or search failed for specified dev
- */
+ memset(&hiscore, 0, sizeof(hiscore));
read_lock(&dev_base_lock);
read_lock(&addrconf_lock);
+
for (dev = dev_base; dev; dev=dev->next) {
+ struct inet6_dev *idev;
+ struct inet6_ifaddr *ifa;
+
+ /* Rule 0: Candidate Source Address (section 4)
+ * - multicast and link-local destination address,
+ * the set of candidate source address MUST only
+ * include addresses assigned to interfaces
+ * belonging to the same link as the outgoing
+ * interface.
+ * (- For site-local destination addresses, the
+ * set of candidate source addresses MUST only
+ * include addresses assigned to interfaces
+ * belonging to the same site as the outgoing
+ * interface.)
+ */
+ if ((daddr_type & IPV6_ADDR_MULTICAST ||
+ daddr_scope <= IPV6_ADDR_SCOPE_LINKLOCAL) &&
+ daddr_dev && dev != daddr_dev)
+ continue;
+
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_TENTATIVE)
- continue;
-#ifdef CONFIG_IPV6_PRIVACY
- score = ipv6_saddr_pref(ifp, idev->cnf.use_tempaddr > 1 ? IFA_F_TEMPORARY : 0);
-#else
- score = ipv6_saddr_pref(ifp, 0);
-#endif
- if (score <= hiscore)
- continue;
+ if (!idev)
+ continue;
- if (match)
- in6_ifa_put(match);
- match = ifp;
- hiscore = score;
- in6_ifa_hold(ifp);
+ read_lock_bh(&idev->lock);
+ for (ifa = idev->addr_list; ifa; ifa = ifa->if_next) {
+ struct ipv6_saddr_score score;
- if (IPV6_GET_SADDR_MAXSCORE(score)) {
- read_unlock_bh(&idev->lock);
- goto out_unlock_base;
- }
+ score.addr_type = __ipv6_addr_type(&ifa->addr);
+
+ /* Rule 0: Candidate Source Address (section 4)
+ * - In any case, anycast addresses, multicast
+ * addresses, and the unspecified address MUST
+ * NOT be included in a candidate set.
+ */
+ if (unlikely(score.addr_type == IPV6_ADDR_ANY ||
+ score.addr_type & IPV6_ADDR_MULTICAST)) {
+ LIMIT_NETDEBUG(KERN_DEBUG
+ "ADDRCONF: unspecified / multicast address"
+ "assigned as unicast address on %s",
+ dev->name);
+ continue;
+ }
+
+ score.attrs = 0;
+ score.matchlen = 0;
+ score.scope = 0;
+ score.rule = 0;
+
+ if (ifa_result == NULL) {
+ /* record it if the first available entry */
+ goto record_it;
+ }
+
+ /* Rule 1: Prefer same address */
+ if (hiscore.rule < 1) {
+ if (ipv6_addr_equal(&ifa_result->addr, daddr))
+ hiscore.attrs |= IPV6_SADDR_SCORE_LOCAL;
+ hiscore.rule++;
+ }
+ if (ipv6_addr_equal(&ifa->addr, daddr)) {
+ score.attrs |= IPV6_SADDR_SCORE_LOCAL;
+ if (!(hiscore.attrs & IPV6_SADDR_SCORE_LOCAL)) {
+ score.rule = 1;
+ goto record_it;
+ }
+ } else {
+ if (hiscore.attrs & IPV6_SADDR_SCORE_LOCAL)
+ continue;
+ }
+
+ /* Rule 2: Prefer appropriate scope */
+ if (hiscore.rule < 2) {
+ hiscore.scope = __ipv6_addr_src_scope(hiscore.addr_type);
+ hiscore.rule++;
+ }
+ score.scope = __ipv6_addr_src_scope(score.addr_type);
+ if (hiscore.scope < score.scope) {
+ if (hiscore.scope < daddr_scope) {
+ score.rule = 2;
+ goto record_it;
+ } else
+ continue;
+ } else if (score.scope < hiscore.scope) {
+ if (score.scope < daddr_scope)
+ continue;
+ else {
+ score.rule = 2;
+ goto record_it;
}
}
- read_unlock_bh(&idev->lock);
- }
- }
-out_unlock_base:
+ /* Rule 3: Avoid deprecated address */
+ if (hiscore.rule < 3) {
+ if (ipv6_saddr_preferred(hiscore.addr_type) ||
+ !(ifa_result->flags & IFA_F_DEPRECATED))
+ hiscore.attrs |= IPV6_SADDR_SCORE_PREFERRED;
+ hiscore.rule++;
+ }
+ if (ipv6_saddr_preferred(score.addr_type) ||
+ !(ifa->flags & IFA_F_DEPRECATED)) {
+ score.attrs |= IPV6_SADDR_SCORE_PREFERRED;
+ if (!(hiscore.attrs & IPV6_SADDR_SCORE_PREFERRED)) {
+ score.rule = 3;
+ goto record_it;
+ }
+ } else {
+ if (hiscore.attrs & IPV6_SADDR_SCORE_PREFERRED)
+ continue;
+ }
+
+ /* Rule 4: Prefer home address -- not implemented yet */
+
+ /* Rule 5: Prefer outgoing interface */
+ if (hiscore.rule < 5) {
+ if (daddr_dev == NULL ||
+ daddr_dev == ifa_result->idev->dev)
+ hiscore.attrs |= IPV6_SADDR_SCORE_OIF;
+ hiscore.rule++;
+ }
+ if (daddr_dev == NULL ||
+ daddr_dev == ifa->idev->dev) {
+ score.attrs |= IPV6_SADDR_SCORE_OIF;
+ if (!(hiscore.attrs & IPV6_SADDR_SCORE_OIF)) {
+ score.rule = 5;
+ goto record_it;
+ }
+ } else {
+ if (hiscore.attrs & IPV6_SADDR_SCORE_OIF)
+ continue;
+ }
+
+ /* Rule 6: Prefer matching label */
+ if (hiscore.rule < 6) {
+ if (ipv6_saddr_label(&ifa_result->addr, hiscore.addr_type) == daddr_label)
+ hiscore.attrs |= IPV6_SADDR_SCORE_LABEL;
+ hiscore.rule++;
+ }
+ if (ipv6_saddr_label(&ifa->addr, score.addr_type) == daddr_label) {
+ score.attrs |= IPV6_SADDR_SCORE_LABEL;
+ if (!(hiscore.attrs & IPV6_SADDR_SCORE_LABEL)) {
+ score.rule = 6;
+ goto record_it;
+ }
+ } else {
+ if (hiscore.attrs & IPV6_SADDR_SCORE_LABEL)
+ continue;
+ }
+
+ /* Rule 7: Prefer public address
+ * Note: prefer temprary address if use_tempaddr >= 2
+ */
+ if (hiscore.rule < 7) {
+ if ((!(ifa_result->flags & IFA_F_TEMPORARY)) ^
+ (ifa_result->idev->cnf.use_tempaddr >= 2))
+ hiscore.attrs |= IPV6_SADDR_SCORE_PRIVACY;
+ hiscore.rule++;
+ }
+ if ((!(ifa->flags & IFA_F_TEMPORARY)) ^
+ (ifa->idev->cnf.use_tempaddr >= 2)) {
+ score.attrs |= IPV6_SADDR_SCORE_PRIVACY;
+ if (!(hiscore.attrs & IPV6_SADDR_SCORE_PRIVACY)) {
+ score.rule = 7;
+ goto record_it;
+ }
+ } else {
+ if (hiscore.attrs & IPV6_SADDR_SCORE_PRIVACY)
+ continue;
+ }
+
+ /* Rule 8: Use longest matching prefix */
+ if (hiscore.rule < 8)
+ hiscore.matchlen = ipv6_addr_diff(&ifa_result->addr, daddr);
+ score.rule++;
+ score.matchlen = ipv6_addr_diff(&ifa->addr, daddr);
+ if (score.matchlen > hiscore.matchlen) {
+ score.rule = 8;
+ goto record_it;
+ }
+#if 0
+ else if (score.matchlen < hiscore.matchlen)
+ continue;
+#endif
+
+ /* Final Rule: choose first available one */
+ continue;
+record_it:
+ if (ifa_result)
+ in6_ifa_put(ifa_result);
+ in6_ifa_hold(ifa);
+ ifa_result = ifa;
+ hiscore = score;
+ }
+ read_unlock_bh(&idev->lock);
+ }
read_unlock(&addrconf_lock);
read_unlock(&dev_base_lock);
-out:
- err = -EADDRNOTAVAIL;
- if (match) {
- ipv6_addr_copy(saddr, &match->addr);
- err = 0;
- in6_ifa_put(match);
- }
-
- return err;
+ if (!ifa_result)
+ return -EADDRNOTAVAIL;
+
+ ipv6_addr_copy(saddr, &ifa_result->addr);
+ in6_ifa_put(ifa_result);
+ return 0;
}