[IPV6]: Support Source Address Selection API (RFC5014).

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

12 files changed, 146 insertions, 13 deletions

diff --git a/include/linux/in6.h b/include/linux/in6.h
index 2a61c82af115..f674000c6c99 100644
--- a/include/linux/in6.h
+++ b/include/linux/in6.h
@@ -249,4 +249,15 @@ struct in6_flowlabel_req
  * IP6T_SO_GET_REVISION_TARGET  69
  */
 
+/* RFC5014: Source address selection */
+#define IPV6_ADDR_PREFERENCES   72
+
+#define IPV6_PREFER_SRC_TMP             0x0001
+#define IPV6_PREFER_SRC_PUBLIC          0x0002
+#define IPV6_PREFER_SRC_PUBTMP_DEFAULT  0x0100
+#define IPV6_PREFER_SRC_COA             0x0004
+#define IPV6_PREFER_SRC_HOME            0x0400
+#define IPV6_PREFER_SRC_CGA             0x0008
+#define IPV6_PREFER_SRC_NONCGA          0x0800
+
 #endif
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 87ae4e389ce1..c9ba0da16ce9 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -322,7 +322,11 @@ struct ipv6_pinfo {
         __u8                    recverr:1,
                                 sndflow:1,
                                 pmtudisc:2,
-                                ipv6only:1;
+                                ipv6only:1,
+                                srcprefs:3;     /* 001: prefer temporary address
+                                                 * 010: prefer public address
+                                                 * 100: prefer care-of address
+                                                 */
         __u8                    tclass;
 
         __u32                   dst_cookie;
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index edcb4bbaab7d..c9276c72764d 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -78,6 +78,7 @@ extern struct inet6_ifaddr      *ipv6_get_ifaddr(struct net *net,
 
 extern int                      ipv6_dev_get_saddr(struct net_device *dev, 
                                                struct in6_addr *daddr,
+                                               unsigned int srcprefs,
                                                struct in6_addr *saddr);
 extern int                      ipv6_get_lladdr(struct net_device *dev,
                                                 struct in6_addr *addr,
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 5c3b67c86aef..3ae6799c2b14 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -30,9 +30,12 @@ struct route_info {
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 
-#define RT6_LOOKUP_F_IFACE      0x1
-#define RT6_LOOKUP_F_REACHABLE  0x2
-#define RT6_LOOKUP_F_HAS_SADDR  0x4
+#define RT6_LOOKUP_F_IFACE              0x00000001
+#define RT6_LOOKUP_F_REACHABLE          0x00000002
+#define RT6_LOOKUP_F_HAS_SADDR          0x00000004
+#define RT6_LOOKUP_F_SRCPREF_TMP        0x00000008
+#define RT6_LOOKUP_F_SRCPREF_PUBLIC     0x00000010
+#define RT6_LOOKUP_F_SRCPREF_COA        0x00000020
 
 extern struct rt6_info  *ip6_null_entry;
 
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 787e90af166c..89954885dee1 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -909,6 +909,7 @@ struct ipv6_saddr_dst {
         int ifindex;
         int scope;
         int label;
+        unsigned int prefs;
 };
 
 static inline int ipv6_saddr_preferred(int type)
@@ -984,9 +985,12 @@ static int ipv6_get_saddr_eval(struct ipv6_saddr_score *score,
                 break;
 #ifdef CONFIG_IPV6_MIP6
         case IPV6_SADDR_RULE_HOA:
+            {
                 /* Rule 4: Prefer home address */
-                ret = !!(score->ifa->flags & IFA_F_HOMEADDRESS);
+                int prefhome = !(dst->prefs & IPV6_PREFER_SRC_COA);
+                ret = !(score->ifa->flags & IFA_F_HOMEADDRESS) ^ prefhome;
                 break;
+            }
 #endif
         case IPV6_SADDR_RULE_OIF:
                 /* Rule 5: Prefer outgoing interface */
@@ -1000,11 +1004,16 @@ static int ipv6_get_saddr_eval(struct ipv6_saddr_score *score,
                 break;
 #ifdef CONFIG_IPV6_PRIVACY
         case IPV6_SADDR_RULE_PRIVACY:
+            {
                 /* Rule 7: Prefer public address
                  * Note: prefer temprary address if use_tempaddr >= 2
                  */
-                ret = (!(score->ifa->flags & IFA_F_TEMPORARY)) ^ (score->ifa->idev->cnf.use_tempaddr >= 2);
+                int preftmp = dst->prefs & (IPV6_PREFER_SRC_PUBLIC|IPV6_PREFER_SRC_TMP) ?
+                                !!(dst->prefs & IPV6_PREFER_SRC_TMP) :
+                                score->ifa->idev->cnf.use_tempaddr >= 2;
+                ret = (!(score->ifa->flags & IFA_F_TEMPORARY)) ^ preftmp;
                 break;
+            }
 #endif
         case IPV6_SADDR_RULE_ORCHID:
                 /* Rule 8-: Prefer ORCHID vs ORCHID or
@@ -1030,7 +1039,8 @@ out:
 }
 
 int ipv6_dev_get_saddr(struct net_device *dst_dev,
-                       struct in6_addr *daddr, struct in6_addr *saddr)
+                       struct in6_addr *daddr, unsigned int prefs,
+                       struct in6_addr *saddr)
 {
         struct ipv6_saddr_score scores[2],
                                 *score = &scores[0], *hiscore = &scores[1];
@@ -1044,6 +1054,7 @@ int ipv6_dev_get_saddr(struct net_device *dst_dev,
         dst.ifindex = dst_dev ? dst_dev->ifindex : 0;
         dst.scope = __ipv6_addr_src_scope(dst_type);
         dst.label = ipv6_addr_label(daddr, dst_type, dst.ifindex);
+        dst.prefs = prefs;
 
         hiscore->rule = -1;
         hiscore->ifa = NULL;
diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 55137408f054..e7a7fe26cebf 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -84,8 +84,18 @@ static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
                 if ((rule->flags & FIB_RULE_FIND_SADDR) &&
                     r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
                         struct in6_addr saddr;
+                        unsigned int srcprefs = 0;
+
+                        if (flags & RT6_LOOKUP_F_SRCPREF_TMP)
+                                srcprefs |= IPV6_PREFER_SRC_TMP;
+                        if (flags & RT6_LOOKUP_F_SRCPREF_PUBLIC)
+                                srcprefs |= IPV6_PREFER_SRC_PUBLIC;
+                        if (flags & RT6_LOOKUP_F_SRCPREF_COA)
+                                srcprefs |= IPV6_PREFER_SRC_COA;
+
                         if (ipv6_dev_get_saddr(ip6_dst_idev(&rt->u.dst)->dev,
-                                               &flp->fl6_dst, &saddr))
+                                               &flp->fl6_dst, srcprefs,
+                                               &saddr))
                                 goto again;
                         if (!ipv6_prefix_equal(&saddr, &r->src.addr,
                                                r->src.plen))
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 2a4f08c8a02d..d34aa61353bb 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -920,7 +920,9 @@ static int ip6_dst_lookup_tail(struct sock *sk,
 
         if (ipv6_addr_any(&fl->fl6_src)) {
                 err = ipv6_dev_get_saddr(ip6_dst_idev(*dst)->dev,
-                                         &fl->fl6_dst, &fl->fl6_src);
+                                         &fl->fl6_dst,
+                                         sk ? inet6_sk(sk)->srcprefs : 0,
+                                         &fl->fl6_src);
                 if (err)
                         goto out_err_release;
         }
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 8e29fb1d1df6..dc6695cc5767 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -617,7 +617,67 @@ done:
                 retv = xfrm_user_policy(sk, optname, optval, optlen);
                 break;
 
+        case IPV6_ADDR_PREFERENCES:
+            {
+                unsigned int pref = 0;
+                unsigned int prefmask = ~0;
+
+                retv = -EINVAL;
+
+                /* check PUBLIC/TMP/PUBTMP_DEFAULT conflicts */
+                switch (val & (IPV6_PREFER_SRC_PUBLIC|
+                               IPV6_PREFER_SRC_TMP|
+                               IPV6_PREFER_SRC_PUBTMP_DEFAULT)) {
+                case IPV6_PREFER_SRC_PUBLIC:
+                        pref |= IPV6_PREFER_SRC_PUBLIC;
+                        break;
+                case IPV6_PREFER_SRC_TMP:
+                        pref |= IPV6_PREFER_SRC_TMP;
+                        break;
+                case IPV6_PREFER_SRC_PUBTMP_DEFAULT:
+                        break;
+                case 0:
+                        goto pref_skip_pubtmp;
+                default:
+                        goto e_inval;
+                }
+
+                prefmask &= ~(IPV6_PREFER_SRC_PUBLIC|
+                              IPV6_PREFER_SRC_TMP);
+pref_skip_pubtmp:
+
+                /* check HOME/COA conflicts */
+                switch (val & (IPV6_PREFER_SRC_HOME|IPV6_PREFER_SRC_COA)) {
+                case IPV6_PREFER_SRC_HOME:
+                        break;
+                case IPV6_PREFER_SRC_COA:
+                        pref |= IPV6_PREFER_SRC_COA;
+                case 0:
+                        goto pref_skip_coa;
+                default:
+                        goto e_inval;
+                }
+
+                prefmask &= ~IPV6_PREFER_SRC_COA;
+pref_skip_coa:
+
+                /* check CGA/NONCGA conflicts */
+                switch (val & (IPV6_PREFER_SRC_CGA|IPV6_PREFER_SRC_NONCGA)) {
+                case IPV6_PREFER_SRC_CGA:
+                case IPV6_PREFER_SRC_NONCGA:
+                case 0:
+                        break;
+                default:
+                        goto e_inval;
+                }
+
+                np->srcprefs = (np->srcprefs & prefmask) | pref;
+                retv = 0;
+
+                break;
+            }
         }
+
         release_sock(sk);
 
         return retv;
@@ -932,6 +992,24 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
                 val = np->sndflow;
                 break;
 
+        case IPV6_ADDR_PREFERENCES:
+                val = 0;
+
+                if (np->srcprefs & IPV6_PREFER_SRC_TMP)
+                        val |= IPV6_PREFER_SRC_TMP;
+                else if (np->srcprefs & IPV6_PREFER_SRC_PUBLIC)
+                        val |= IPV6_PREFER_SRC_PUBLIC;
+                else {
+                        /* XXX: should we return system default? */
+                        val |= IPV6_PREFER_SRC_PUBTMP_DEFAULT;
+                }
+
+                if (np->srcprefs & IPV6_PREFER_SRC_COA)
+                        val |= IPV6_PREFER_SRC_COA;
+                else
+                        val |= IPV6_PREFER_SRC_HOME;
+                break;
+
         default:
                 return -ENOPROTOOPT;
         }
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index e7d8e74704c1..3f68a6eae7b2 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -546,7 +546,9 @@ static void ndisc_send_na(struct net_device *dev, struct neighbour *neigh,
                         override = 0;
                 in6_ifa_put(ifp);
         } else {
-                if (ipv6_dev_get_saddr(dev, daddr, &tmpaddr))
+                if (ipv6_dev_get_saddr(dev, daddr,
+                                       inet6_sk(dev->nd_net->ipv6.ndisc_sk)->srcprefs,
+                                       &tmpaddr))
                         return;
                 src_addr = &tmpaddr;
         }
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index aa3f08718e44..06faa46920e1 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -782,6 +782,15 @@ struct dst_entry * ip6_route_output(struct net *net, struct sock *sk,
 
         if (!ipv6_addr_any(&fl->fl6_src))
                 flags |= RT6_LOOKUP_F_HAS_SADDR;
+        else if (sk) {
+                unsigned int prefs = inet6_sk(sk)->srcprefs;
+                if (prefs & IPV6_PREFER_SRC_TMP)
+                        flags |= RT6_LOOKUP_F_SRCPREF_TMP;
+                if (prefs & IPV6_PREFER_SRC_PUBLIC)
+                        flags |= RT6_LOOKUP_F_SRCPREF_PUBLIC;
+                if (prefs & IPV6_PREFER_SRC_COA)
+                        flags |= RT6_LOOKUP_F_SRCPREF_COA;
+        }
 
         return fib6_rule_lookup(net, fl, flags, ip6_pol_route_output);
 }
@@ -2162,7 +2171,7 @@ static int rt6_fill_node(struct sk_buff *skb, struct rt6_info *rt,
         else if (dst) {
                 struct in6_addr saddr_buf;
                 if (ipv6_dev_get_saddr(ip6_dst_idev(&rt->u.dst)->dev,
-                                       dst, &saddr_buf) == 0)
+                                       dst, 0, &saddr_buf) == 0)
                         NLA_PUT(skb, RTA_PREFSRC, 16, &saddr_buf);
         }
 
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index e96dafdc7032..d92d1fceb8cf 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -58,7 +58,7 @@ static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
                 return -EHOSTUNREACH;
 
         ipv6_dev_get_saddr(ip6_dst_idev(dst)->dev,
-                           (struct in6_addr *)&daddr->a6,
+                           (struct in6_addr *)&daddr->a6, 0,
                            (struct in6_addr *)&saddr->a6);
         dst_release(dst);
         return 0;
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 46c5b3c5cb99..dc71d0d83753 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -316,7 +316,9 @@ static void sctp_v6_get_saddr(struct sctp_association *asoc,
 
         if (!asoc) {
                 ipv6_dev_get_saddr(dst ? ip6_dst_idev(dst)->dev : NULL,
-                                   &daddr->v6.sin6_addr, &saddr->v6.sin6_addr);
+                                   &daddr->v6.sin6_addr,
+                                   inet6_sk(asoc->base.sk)->srcprefs,
+                                   &saddr->v6.sin6_addr);
                 SCTP_DEBUG_PRINTK("saddr from ipv6_get_saddr: " NIP6_FMT "\n",
                                   NIP6(saddr->v6.sin6_addr));
                 return;