[IPV6] ROUTE: Routing by FWMARK.

Based on patch by Jean Lorchat <lorchat@sfc.wide.ad.jp>.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

include/linux/fib_rules.h

@@ -34,7 +34,7 @@ enum
 	FRA_UNUSED3,
 	FRA_UNUSED4,
 	FRA_UNUSED5,
-	FRA_FWMARK,	/* netfilter mark (IPv4) */
+	FRA_FWMARK,	/* netfilter mark (IPv4/IPv6) */
 	FRA_FLOW,	/* flow/class id */
 	FRA_UNUSED6,
 	FRA_UNUSED7,

include/net/flow.h

@@ -26,6 +26,7 @@ struct flowi {
 		struct {
 			struct in6_addr		daddr;
 			struct in6_addr		saddr;
+			__u32			fwmark;
 			__u32			flowlabel;
 		} ip6_u;
 
@@ -42,6 +43,7 @@ struct flowi {
 #define fld_scope	nl_u.dn_u.scope
 #define fl6_dst		nl_u.ip6_u.daddr
 #define fl6_src		nl_u.ip6_u.saddr
+#define fl6_fwmark	nl_u.ip6_u.fwmark
 #define fl6_flowlabel	nl_u.ip6_u.flowlabel
 #define fl4_dst		nl_u.ip4_u.daddr
 #define fl4_src		nl_u.ip4_u.saddr

net/ipv6/Kconfig

@@ -173,3 +173,10 @@ config IPV6_MULTIPLE_TABLES
 	---help---
 	  Support multiple routing tables.
 
+config IPV6_ROUTE_FWMARK
+	bool "IPv6: use netfilter MARK value as routing key"
+	depends on IPV6_MULTIPLE_TABLES && NETFILTER
+	---help---
+	  If you say Y here, you will be able to specify different routes for
+	  packets with different mark values (see iptables(8), MARK target).
+

net/ipv6/fib6_rules.c

@@ -26,6 +26,9 @@ struct fib6_rule
 	struct fib_rule		common;
 	struct rt6key		src;
 	struct rt6key		dst;
+#ifdef CONFIG_IPV6_ROUTE_FWMARK
+	u8			fwmark;
+#endif
 	u8			tclass;
 };
 
@@ -124,6 +127,11 @@ static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 	if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff))
 		return 0;
 
+#ifdef CONFIG_IPV6_ROUTE_FWMARK
+	if (r->fwmark && (r->fwmark != fl->fl6_fwmark))
+		return 0;
+#endif
+
 	return 1;
 }
 
@@ -164,6 +172,11 @@ static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 		nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
 			   sizeof(struct in6_addr));
 
+#ifdef CONFIG_IPV6_ROUTE_FWMARK
+	if (tb[FRA_FWMARK])
+		rule6->fwmark = nla_get_u32(tb[FRA_FWMARK]);
+#endif
+
 	rule6->src.plen = frh->src_len;
 	rule6->dst.plen = frh->dst_len;
 	rule6->tclass = frh->tos;
@@ -195,6 +208,11 @@ static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 	    nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
 		return 0;
 
+#ifdef CONFIG_IPV6_ROUTE_FWMARK
+	if (tb[FRA_FWMARK] && (rule6->fwmark != nla_get_u32(tb[FRA_FWMARK])))
+		return 0;
+#endif
+
 	return 1;
 }
 
@@ -216,6 +234,11 @@ static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 		NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
 			&rule6->src.addr);
 
+#ifdef CONFIG_IPV6_ROUTE_FWMARK
+	if (rule6->fwmark)
+		NLA_PUT_U32(skb, FRA_FWMARK, rule6->fwmark);
+#endif
+
 	return 0;
 
 nla_put_failure:

net/ipv6/route.c

@@ -703,6 +703,7 @@ void ip6_route_input(struct sk_buff *skb)
 			.ip6_u = {
 				.daddr = iph->daddr,
 				.saddr = iph->saddr,
+				.fwmark = skb->nfmark,
 				.flowlabel = (* (u32 *) iph)&IPV6_FLOWINFO_MASK,
 			},
 		},