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

Signed-off-by: YOSHIFUJI Hideaki <[e-mail]>

include/linux/in6.h

···
  * 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

include/linux/ipv6.h

···
 	__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;

include/net/addrconf.h

···
 
 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,

include/net/ip6_route.h

···
 #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;
 

net/ipv6/addrconf.c

···
 	int ifindex;
 	int scope;
 	int label;
+	unsigned int prefs;
 };
 
 static inline int ipv6_saddr_preferred(int type)
···
 		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 */
···
 		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
···
 }
 
 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];
···
 	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;

net/ipv6/fib6_rules.c

···
 		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))

net/ipv6/ip6_output.c

···
 
 	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;
 	}

net/ipv6/ipv6_sockglue.c

···
 		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;
···
 
 	case IPV6_FLOWINFO_SEND:
 		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:

net/ipv6/ndisc.c

···
 			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;
 	}

net/ipv6/route.c

···
 
 	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);
 }
···
 	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);
 	}
 

net/ipv6/xfrm6_policy.c

···
 		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;

net/sctp/ipv6.c

···
 
 	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;