2 files changed, 111 insertions, 38 deletions

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 1c58662db4b2..c70d750148b6 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -57,6 +57,20 @@ bool mpls_output_possible(const struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(mpls_output_possible);
 
+static u8 *__mpls_nh_via(struct mpls_route *rt, struct mpls_nh *nh)
+{
+	u8 *nh0_via = PTR_ALIGN((u8 *)&rt->rt_nh[rt->rt_nhn], VIA_ALEN_ALIGN);
+	int nh_index = nh - rt->rt_nh;
+
+	return nh0_via + rt->rt_max_alen * nh_index;
+}
+
+static const u8 *mpls_nh_via(const struct mpls_route *rt,
+			     const struct mpls_nh *nh)
+{
+	return __mpls_nh_via((struct mpls_route *)rt, (struct mpls_nh *)nh);
+}
+
 static unsigned int mpls_nh_header_size(const struct mpls_nh *nh)
 {
 	/* The size of the layer 2.5 labels to be added for this route */
@@ -303,7 +317,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
 		}
 	}
 
-	err = neigh_xmit(nh->nh_via_table, out_dev, nh->nh_via, skb);
+	err = neigh_xmit(nh->nh_via_table, out_dev, mpls_nh_via(rt, nh), skb);
 	if (err)
 		net_dbg_ratelimited("%s: packet transmission failed: %d\n",
 				    __func__, err);
@@ -340,14 +354,19 @@ struct mpls_route_config {
 	int			rc_mp_len;
 };
 
-static struct mpls_route *mpls_rt_alloc(int num_nh)
+static struct mpls_route *mpls_rt_alloc(int num_nh, u8 max_alen)
 {
+	u8 max_alen_aligned = ALIGN(max_alen, VIA_ALEN_ALIGN);
 	struct mpls_route *rt;
 
-	rt = kzalloc(sizeof(*rt) + (num_nh * sizeof(struct mpls_nh)),
+	rt = kzalloc(ALIGN(sizeof(*rt) + num_nh * sizeof(*rt->rt_nh),
+			   VIA_ALEN_ALIGN) +
+		     num_nh * max_alen_aligned,
 		     GFP_KERNEL);
-	if (rt)
+	if (rt) {
 		rt->rt_nhn = num_nh;
+		rt->rt_max_alen = max_alen_aligned;
+	}
 
 	return rt;
 }
@@ -408,7 +427,8 @@ static unsigned find_free_label(struct net *net)
 }
 
 #if IS_ENABLED(CONFIG_INET)
-static struct net_device *inet_fib_lookup_dev(struct net *net, void *addr)
+static struct net_device *inet_fib_lookup_dev(struct net *net,
+					      const void *addr)
 {
 	struct net_device *dev;
 	struct rtable *rt;
@@ -427,14 +447,16 @@ static struct net_device *inet_fib_lookup_dev(struct net *net, void *addr)
 	return dev;
 }
 #else
-static struct net_device *inet_fib_lookup_dev(struct net *net, void *addr)
+static struct net_device *inet_fib_lookup_dev(struct net *net,
+					      const void *addr)
 {
 	return ERR_PTR(-EAFNOSUPPORT);
 }
 #endif
 
 #if IS_ENABLED(CONFIG_IPV6)
-static struct net_device *inet6_fib_lookup_dev(struct net *net, void *addr)
+static struct net_device *inet6_fib_lookup_dev(struct net *net,
+					       const void *addr)
 {
 	struct net_device *dev;
 	struct dst_entry *dst;
@@ -457,13 +479,15 @@ static struct net_device *inet6_fib_lookup_dev(struct net *net, void *addr)
 	return dev;
 }
 #else
-static struct net_device *inet6_fib_lookup_dev(struct net *net, void *addr)
+static struct net_device *inet6_fib_lookup_dev(struct net *net,
+					       const void *addr)
 {
 	return ERR_PTR(-EAFNOSUPPORT);
 }
 #endif
 
 static struct net_device *find_outdev(struct net *net,
+				      struct mpls_route *rt,
 				      struct mpls_nh *nh, int oif)
 {
 	struct net_device *dev = NULL;
@@ -471,10 +495,10 @@ static struct net_device *find_outdev(struct net *net,
 	if (!oif) {
 		switch (nh->nh_via_table) {
 		case NEIGH_ARP_TABLE:
-			dev = inet_fib_lookup_dev(net, nh->nh_via);
+			dev = inet_fib_lookup_dev(net, mpls_nh_via(rt, nh));
 			break;
 		case NEIGH_ND_TABLE:
-			dev = inet6_fib_lookup_dev(net, nh->nh_via);
+			dev = inet6_fib_lookup_dev(net, mpls_nh_via(rt, nh));
 			break;
 		case NEIGH_LINK_TABLE:
 			break;
@@ -492,12 +516,13 @@ static struct net_device *find_outdev(struct net *net,
 	return dev;
 }
 
-static int mpls_nh_assign_dev(struct net *net, struct mpls_nh *nh, int oif)
+static int mpls_nh_assign_dev(struct net *net, struct mpls_route *rt,
+			      struct mpls_nh *nh, int oif)
 {
 	struct net_device *dev = NULL;
 	int err = -ENODEV;
 
-	dev = find_outdev(net, nh, oif);
+	dev = find_outdev(net, rt, nh, oif);
 	if (IS_ERR(dev)) {
 		err = PTR_ERR(dev);
 		dev = NULL;
@@ -538,10 +563,10 @@ static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg,
 		nh->nh_label[i] = cfg->rc_output_label[i];
 
 	nh->nh_via_table = cfg->rc_via_table;
-	memcpy(nh->nh_via, cfg->rc_via, cfg->rc_via_alen);
+	memcpy(__mpls_nh_via(rt, nh), cfg->rc_via, cfg->rc_via_alen);
 	nh->nh_via_alen = cfg->rc_via_alen;
 
-	err = mpls_nh_assign_dev(net, nh, cfg->rc_ifindex);
+	err = mpls_nh_assign_dev(net, rt, nh, cfg->rc_ifindex);
 	if (err)
 		goto errout;
 
@@ -551,8 +576,9 @@ errout:
 	return err;
 }
 
-static int mpls_nh_build(struct net *net, struct mpls_nh *nh,
-			 int oif, struct nlattr *via, struct nlattr *newdst)
+static int mpls_nh_build(struct net *net, struct mpls_route *rt,
+			 struct mpls_nh *nh, int oif,
+			 struct nlattr *via, struct nlattr *newdst)
 {
 	int err = -ENOMEM;
 
@@ -567,11 +593,11 @@ static int mpls_nh_build(struct net *net, struct mpls_nh *nh,
 	}
 
 	err = nla_get_via(via, &nh->nh_via_alen, &nh->nh_via_table,
-			  nh->nh_via);
+			  __mpls_nh_via(rt, nh));
 	if (err)
 		goto errout;
 
-	err = mpls_nh_assign_dev(net, nh, oif);
+	err = mpls_nh_assign_dev(net, rt, nh, oif);
 	if (err)
 		goto errout;
 
@@ -581,12 +607,35 @@ errout:
 	return err;
 }
 
-static int mpls_count_nexthops(struct rtnexthop *rtnh, int len)
+static int mpls_count_nexthops(struct rtnexthop *rtnh, int len,
+			       u8 cfg_via_alen, u8 *max_via_alen)
 {
 	int nhs = 0;
 	int remaining = len;
 
+	if (!rtnh) {
+		*max_via_alen = cfg_via_alen;
+		return 1;
+	}
+
+	*max_via_alen = 0;
+
 	while (rtnh_ok(rtnh, remaining)) {
+		struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
+		int attrlen;
+
+		attrlen = rtnh_attrlen(rtnh);
+		nla = nla_find(attrs, attrlen, RTA_VIA);
+		if (nla && nla_len(nla) >=
+		    offsetof(struct rtvia, rtvia_addr)) {
+			int via_alen = nla_len(nla) -
+				offsetof(struct rtvia, rtvia_addr);
+
+			if (via_alen <= MAX_VIA_ALEN)
+				*max_via_alen = max_t(u16, *max_via_alen,
+						      via_alen);
+		}
+
 		nhs++;
 		rtnh = rtnh_next(rtnh, &remaining);
 	}
@@ -631,7 +680,7 @@ static int mpls_nh_build_multi(struct mpls_route_config *cfg,
 		if (!nla_via)
 			goto errout;
 
-		err = mpls_nh_build(cfg->rc_nlinfo.nl_net, nh,
+		err = mpls_nh_build(cfg->rc_nlinfo.nl_net, rt, nh,
 				    rtnh->rtnh_ifindex, nla_via,
 				    nla_newdst);
 		if (err)
@@ -655,8 +704,9 @@ static int mpls_route_add(struct mpls_route_config *cfg)
 	struct net *net = cfg->rc_nlinfo.nl_net;
 	struct mpls_route *rt, *old;
 	int err = -EINVAL;
+	u8 max_via_alen;
 	unsigned index;
-	int nhs = 1; /* default to one nexthop */
+	int nhs;
 
 	index = cfg->rc_label;
 
@@ -693,15 +743,14 @@ static int mpls_route_add(struct mpls_route_config *cfg)
 	if (!(cfg->rc_nlflags & NLM_F_CREATE) && !old)
 		goto errout;
 
-	if (cfg->rc_mp) {
-		err = -EINVAL;
-		nhs = mpls_count_nexthops(cfg->rc_mp, cfg->rc_mp_len);
-		if (nhs == 0)
-			goto errout;
-	}
+	err = -EINVAL;
+	nhs = mpls_count_nexthops(cfg->rc_mp, cfg->rc_mp_len,
+				  cfg->rc_via_alen, &max_via_alen);
+	if (nhs == 0)
+		goto errout;
 
 	err = -ENOMEM;
-	rt = mpls_rt_alloc(nhs);
+	rt = mpls_rt_alloc(nhs, max_via_alen);
 	if (!rt)
 		goto errout;
 
@@ -1176,13 +1225,13 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
 	if (nla_put_labels(skb, RTA_DST, 1, &label))
 		goto nla_put_failure;
 	if (rt->rt_nhn == 1) {
-		struct mpls_nh *nh = rt->rt_nh;
+		const struct mpls_nh *nh = rt->rt_nh;
 
 		if (nh->nh_labels &&
 		    nla_put_labels(skb, RTA_NEWDST, nh->nh_labels,
 				   nh->nh_label))
 			goto nla_put_failure;
-		if (nla_put_via(skb, nh->nh_via_table, nh->nh_via,
+		if (nla_put_via(skb, nh->nh_via_table, mpls_nh_via(rt, nh),
 				nh->nh_via_alen))
 			goto nla_put_failure;
 		dev = rtnl_dereference(nh->nh_dev);
@@ -1209,7 +1258,7 @@ static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
 							    nh->nh_label))
 				goto nla_put_failure;
 			if (nla_put_via(skb, nh->nh_via_table,
-					nh->nh_via,
+					mpls_nh_via(rt, nh),
 					nh->nh_via_alen))
 				goto nla_put_failure;
 
@@ -1338,7 +1387,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
 	/* In case the predefined labels need to be populated */
 	if (limit > MPLS_LABEL_IPV4NULL) {
 		struct net_device *lo = net->loopback_dev;
-		rt0 = mpls_rt_alloc(1);
+		rt0 = mpls_rt_alloc(1, lo->addr_len);
 		if (!rt0)
 			goto nort0;
 		RCU_INIT_POINTER(rt0->rt_nh->nh_dev, lo);
@@ -1346,11 +1395,12 @@ static int resize_platform_label_table(struct net *net, size_t limit)
 		rt0->rt_payload_type = MPT_IPV4;
 		rt0->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
 		rt0->rt_nh->nh_via_alen = lo->addr_len;
-		memcpy(rt0->rt_nh->nh_via, lo->dev_addr, lo->addr_len);
+		memcpy(__mpls_nh_via(rt0, rt0->rt_nh), lo->dev_addr,
+		       lo->addr_len);
 	}
 	if (limit > MPLS_LABEL_IPV6NULL) {
 		struct net_device *lo = net->loopback_dev;
-		rt2 = mpls_rt_alloc(1);
+		rt2 = mpls_rt_alloc(1, lo->addr_len);
 		if (!rt2)
 			goto nort2;
 		RCU_INIT_POINTER(rt2->rt_nh->nh_dev, lo);
@@ -1358,7 +1408,8 @@ static int resize_platform_label_table(struct net *net, size_t limit)
 		rt2->rt_payload_type = MPT_IPV6;
 		rt2->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
 		rt2->rt_nh->nh_via_alen = lo->addr_len;
-		memcpy(rt2->rt_nh->nh_via, lo->dev_addr, lo->addr_len);
+		memcpy(__mpls_nh_via(rt2, rt2->rt_nh), lo->dev_addr,
+		       lo->addr_len);
 	}
 
 	rtnl_lock();
diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index d7757be39877..bde52ce88c94 100644
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -25,7 +25,8 @@ struct sk_buff;
 #define MAX_NEW_LABELS 2
 
 /* This maximum ha length copied from the definition of struct neighbour */
-#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long)))
+#define VIA_ALEN_ALIGN sizeof(unsigned long)
+#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, VIA_ALEN_ALIGN))
 
 enum mpls_payload_type {
 	MPT_UNSPEC, /* IPv4 or IPv6 */
@@ -44,14 +45,35 @@ struct mpls_nh { /* next hop label forwarding entry */
 	u8			nh_labels;
 	u8			nh_via_alen;
 	u8			nh_via_table;
-	u8			nh_via[MAX_VIA_ALEN];
 };
 
+/* The route, nexthops and vias are stored together in the same memory
+ * block:
+ *
+ * +----------------------+
+ * | mpls_route           |
+ * +----------------------+
+ * | mpls_nh 0            |
+ * +----------------------+
+ * | ...                  |
+ * +----------------------+
+ * | mpls_nh n-1          |
+ * +----------------------+
+ * | alignment padding    |
+ * +----------------------+
+ * | via[rt_max_alen] 0   |
+ * +----------------------+
+ * | ...                  |
+ * +----------------------+
+ * | via[rt_max_alen] n-1 |
+ * +----------------------+
+ */
 struct mpls_route { /* next hop label forwarding entry */
 	struct rcu_head		rt_rcu;
 	u8			rt_protocol;
 	u8			rt_payload_type;
-	int			rt_nhn;
+	u8			rt_max_alen;
+	unsigned int		rt_nhn;
 	struct mpls_nh		rt_nh[0];
 };