5 files changed, 295 insertions, 62 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index cfae0a1529a1..58fbde244381 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -370,6 +370,21 @@ static int call_fib6_entry_notifier(struct notifier_block *nb,
 	return call_fib6_notifier(nb, event_type, &info.info);
 }
 
+static int call_fib6_multipath_entry_notifier(struct notifier_block *nb,
+					      enum fib_event_type event_type,
+					      struct fib6_info *rt,
+					      unsigned int nsiblings,
+					      struct netlink_ext_ack *extack)
+{
+	struct fib6_entry_notifier_info info = {
+		.info.extack = extack,
+		.rt = rt,
+		.nsiblings = nsiblings,
+	};
+
+	return call_fib6_notifier(nb, event_type, &info.info);
+}
+
 int call_fib6_entry_notifiers(struct net *net,
 			      enum fib_event_type event_type,
 			      struct fib6_info *rt,
@@ -400,6 +415,17 @@ int call_fib6_multipath_entry_notifiers(struct net *net,
 	return call_fib6_notifiers(net, event_type, &info.info);
 }
 
+int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt)
+{
+	struct fib6_entry_notifier_info info = {
+		.rt = rt,
+		.nsiblings = rt->fib6_nsiblings,
+	};
+
+	rt->fib6_table->fib_seq++;
+	return call_fib6_notifiers(net, FIB_EVENT_ENTRY_REPLACE, &info.info);
+}
+
 struct fib6_dump_arg {
 	struct net *net;
 	struct notifier_block *nb;
@@ -408,22 +434,29 @@ struct fib6_dump_arg {
 
 static int fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
 {
-	if (rt == arg->net->ipv6.fib6_null_entry)
+	enum fib_event_type fib_event = FIB_EVENT_ENTRY_REPLACE;
+	int err;
+
+	if (!rt || rt == arg->net->ipv6.fib6_null_entry)
 		return 0;
-	return call_fib6_entry_notifier(arg->nb, FIB_EVENT_ENTRY_ADD,
-					rt, arg->extack);
+
+	if (rt->fib6_nsiblings)
+		err = call_fib6_multipath_entry_notifier(arg->nb, fib_event,
+							 rt,
+							 rt->fib6_nsiblings,
+							 arg->extack);
+	else
+		err = call_fib6_entry_notifier(arg->nb, fib_event, rt,
+					       arg->extack);
+
+	return err;
 }
 
 static int fib6_node_dump(struct fib6_walker *w)
 {
-	struct fib6_info *rt;
-	int err = 0;
+	int err;
 
-	for_each_fib6_walker_rt(w) {
-		err = fib6_rt_dump(rt, w->args);
-		if (err)
-			break;
-	}
+	err = fib6_rt_dump(w->leaf, w->args);
 	w->leaf = NULL;
 	return err;
 }
@@ -1039,6 +1072,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
 		   (info->nlh->nlmsg_flags & NLM_F_CREATE));
 	int found = 0;
 	bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
+	bool notify_sibling_rt = false;
 	u16 nlflags = NLM_F_EXCL;
 	int err;
 
@@ -1130,6 +1164,7 @@ next_iter:
 
 		/* Find the first route that have the same metric */
 		sibling = leaf;
+		notify_sibling_rt = true;
 		while (sibling) {
 			if (sibling->fib6_metric == rt->fib6_metric &&
 			    rt6_qualify_for_ecmp(sibling)) {
@@ -1139,6 +1174,7 @@ next_iter:
 			}
 			sibling = rcu_dereference_protected(sibling->fib6_next,
 				    lockdep_is_held(&rt->fib6_table->tb6_lock));
+			notify_sibling_rt = false;
 		}
 		/* For each sibling in the list, increment the counter of
 		 * siblings. BUG() if counters does not match, list of siblings
@@ -1165,10 +1201,21 @@ next_iter:
 add:
 		nlflags |= NLM_F_CREATE;
 
-		if (!info->skip_notify_kernel) {
+		/* The route should only be notified if it is the first
+		 * route in the node or if it is added as a sibling
+		 * route to the first route in the node.
+		 */
+		if (!info->skip_notify_kernel &&
+		    (notify_sibling_rt || ins == &fn->leaf)) {
+			enum fib_event_type fib_event;
+
+			if (notify_sibling_rt)
+				fib_event = FIB_EVENT_ENTRY_APPEND;
+			else
+				fib_event = FIB_EVENT_ENTRY_REPLACE;
 			err = call_fib6_entry_notifiers(info->nl_net,
-							FIB_EVENT_ENTRY_ADD,
-							rt, extack);
+							fib_event, rt,
+							extack);
 			if (err) {
 				struct fib6_info *sibling, *next_sibling;
 
@@ -1212,7 +1259,7 @@ add:
 			return -ENOENT;
 		}
 
-		if (!info->skip_notify_kernel) {
+		if (!info->skip_notify_kernel && ins == &fn->leaf) {
 			err = call_fib6_entry_notifiers(info->nl_net,
 							FIB_EVENT_ENTRY_REPLACE,
 							rt, extack);
@@ -1845,13 +1892,29 @@ static struct fib6_node *fib6_repair_tree(struct net *net,
 static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
 			   struct fib6_info __rcu **rtp, struct nl_info *info)
 {
+	struct fib6_info *leaf, *replace_rt = NULL;
 	struct fib6_walker *w;
 	struct fib6_info *rt = rcu_dereference_protected(*rtp,
 				    lockdep_is_held(&table->tb6_lock));
 	struct net *net = info->nl_net;
+	bool notify_del = false;
 
 	RT6_TRACE("fib6_del_route\n");
 
+	/* If the deleted route is the first in the node and it is not part of
+	 * a multipath route, then we need to replace it with the next route
+	 * in the node, if exists.
+	 */
+	leaf = rcu_dereference_protected(fn->leaf,
+					 lockdep_is_held(&table->tb6_lock));
+	if (leaf == rt && !rt->fib6_nsiblings) {
+		if (rcu_access_pointer(rt->fib6_next))
+			replace_rt = rcu_dereference_protected(rt->fib6_next,
+					    lockdep_is_held(&table->tb6_lock));
+		else
+			notify_del = true;
+	}
+
 	/* Unlink it */
 	*rtp = rt->fib6_next;
 	rt->fib6_node = NULL;
@@ -1869,6 +1932,14 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
 	if (rt->fib6_nsiblings) {
 		struct fib6_info *sibling, *next_sibling;
 
+		/* The route is deleted from a multipath route. If this
+		 * multipath route is the first route in the node, then we need
+		 * to emit a delete notification. Otherwise, we need to skip
+		 * the notification.
+		 */
+		if (rt->fib6_metric == leaf->fib6_metric &&
+		    rt6_qualify_for_ecmp(leaf))
+			notify_del = true;
 		list_for_each_entry_safe(sibling, next_sibling,
 					 &rt->fib6_siblings, fib6_siblings)
 			sibling->fib6_nsiblings--;
@@ -1904,8 +1975,13 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
 
 	fib6_purge_rt(rt, fn, net);
 
-	if (!info->skip_notify_kernel)
-		call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, rt, NULL);
+	if (!info->skip_notify_kernel) {
+		if (notify_del)
+			call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
+						  rt, NULL);
+		else if (replace_rt)
+			call_fib6_entry_notifiers_replace(net, replace_rt);
+	}
 	if (!info->skip_notify)
 		inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
 
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index affb51c11a25..4fbdc60b4e07 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3757,6 +3757,7 @@ static int __ip6_del_rt_siblings(struct fib6_info *rt, struct fib6_config *cfg)
 
 	if (rt->fib6_nsiblings && cfg->fc_delete_all_nh) {
 		struct fib6_info *sibling, *next_sibling;
+		struct fib6_node *fn;
 
 		/* prefer to send a single notification with all hops */
 		skb = nlmsg_new(rt6_nlmsg_size(rt), gfp_any());
@@ -3772,12 +3773,32 @@ static int __ip6_del_rt_siblings(struct fib6_info *rt, struct fib6_config *cfg)
 				info->skip_notify = 1;
 		}
 
+		/* 'rt' points to the first sibling route. If it is not the
+		 * leaf, then we do not need to send a notification. Otherwise,
+		 * we need to check if the last sibling has a next route or not
+		 * and emit a replace or delete notification, respectively.
+		 */
 		info->skip_notify_kernel = 1;
-		call_fib6_multipath_entry_notifiers(net,
-						    FIB_EVENT_ENTRY_DEL,
-						    rt,
-						    rt->fib6_nsiblings,
-						    NULL);
+		fn = rcu_dereference_protected(rt->fib6_node,
+					    lockdep_is_held(&table->tb6_lock));
+		if (rcu_access_pointer(fn->leaf) == rt) {
+			struct fib6_info *last_sibling, *replace_rt;
+
+			last_sibling = list_last_entry(&rt->fib6_siblings,
+						       struct fib6_info,
+						       fib6_siblings);
+			replace_rt = rcu_dereference_protected(
+					    last_sibling->fib6_next,
+					    lockdep_is_held(&table->tb6_lock));
+			if (replace_rt)
+				call_fib6_entry_notifiers_replace(net,
+								  replace_rt);
+			else
+				call_fib6_multipath_entry_notifiers(net,
+						       FIB_EVENT_ENTRY_DEL,
+						       rt, rt->fib6_nsiblings,
+						       NULL);
+		}
 		list_for_each_entry_safe(sibling, next_sibling,
 					 &rt->fib6_siblings,
 					 fib6_siblings) {
@@ -5025,12 +5046,37 @@ static void ip6_route_mpath_notify(struct fib6_info *rt,
 		inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
 }
 
+static bool ip6_route_mpath_should_notify(const struct fib6_info *rt)
+{
+	bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
+	bool should_notify = false;
+	struct fib6_info *leaf;
+	struct fib6_node *fn;
+
+	rcu_read_lock();
+	fn = rcu_dereference(rt->fib6_node);
+	if (!fn)
+		goto out;
+
+	leaf = rcu_dereference(fn->leaf);
+	if (!leaf)
+		goto out;
+
+	if (rt == leaf ||
+	    (rt_can_ecmp && rt->fib6_metric == leaf->fib6_metric &&
+	     rt6_qualify_for_ecmp(leaf)))
+		should_notify = true;
+out:
+	rcu_read_unlock();
+
+	return should_notify;
+}
+
 static int ip6_route_multipath_add(struct fib6_config *cfg,
 				   struct netlink_ext_ack *extack)
 {
 	struct fib6_info *rt_notif = NULL, *rt_last = NULL;
 	struct nl_info *info = &cfg->fc_nlinfo;
-	enum fib_event_type event_type;
 	struct fib6_config r_cfg;
 	struct rtnexthop *rtnh;
 	struct fib6_info *rt;
@@ -5155,13 +5201,27 @@ static int ip6_route_multipath_add(struct fib6_config *cfg,
 		nhn++;
 	}
 
-	event_type = replace ? FIB_EVENT_ENTRY_REPLACE : FIB_EVENT_ENTRY_ADD;
-	err = call_fib6_multipath_entry_notifiers(info->nl_net, event_type,
-						  rt_notif, nhn - 1, extack);
-	if (err) {
-		/* Delete all the siblings that were just added */
-		err_nh = NULL;
-		goto add_errout;
+	/* An in-kernel notification should only be sent in case the new
+	 * multipath route is added as the first route in the node, or if
+	 * it was appended to it. We pass 'rt_notif' since it is the first
+	 * sibling and might allow us to skip some checks in the replace case.
+	 */
+	if (ip6_route_mpath_should_notify(rt_notif)) {
+		enum fib_event_type fib_event;
+
+		if (rt_notif->fib6_nsiblings != nhn - 1)
+			fib_event = FIB_EVENT_ENTRY_APPEND;
+		else
+			fib_event = FIB_EVENT_ENTRY_REPLACE;
+
+		err = call_fib6_multipath_entry_notifiers(info->nl_net,
+							  fib_event, rt_notif,
+							  nhn - 1, extack);
+		if (err) {
+			/* Delete all the siblings that were just added */
+			err_nh = NULL;
+			goto add_errout;
+		}
 	}
 
 	/* success ... tell user about new route */
@@ -5516,6 +5576,13 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb,
 		expires -= jiffies;
 	}
 
+	if (!dst) {
+		if (rt->offload)
+			rtm->rtm_flags |= RTM_F_OFFLOAD;
+		if (rt->trap)
+			rtm->rtm_flags |= RTM_F_TRAP;
+	}
+
 	if (rtnl_put_cacheinfo(skb, dst, 0, expires, dst ? dst->error : 0) < 0)
 		goto nla_put_failure;
 
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index df5fd9109696..33a578a3eb3a 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -75,13 +75,14 @@ static void	tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 static int	tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
 
 static const struct inet_connection_sock_af_ops ipv6_mapped;
-static const struct inet_connection_sock_af_ops ipv6_specific;
+const struct inet_connection_sock_af_ops ipv6_specific;
 #ifdef CONFIG_TCP_MD5SIG
 static const struct tcp_sock_af_ops tcp_sock_ipv6_specific;
 static const struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
 #else
 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
-						   const struct in6_addr *addr)
+						   const struct in6_addr *addr,
+						   int l3index)
 {
 	return NULL;
 }
@@ -237,6 +238,8 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
 
 		icsk->icsk_af_ops = &ipv6_mapped;
+		if (sk_is_mptcp(sk))
+			mptcp_handle_ipv6_mapped(sk, true);
 		sk->sk_backlog_rcv = tcp_v4_do_rcv;
 #ifdef CONFIG_TCP_MD5SIG
 		tp->af_specific = &tcp_sock_ipv6_mapped_specific;
@@ -247,6 +250,8 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 		if (err) {
 			icsk->icsk_ext_hdr_len = exthdrlen;
 			icsk->icsk_af_ops = &ipv6_specific;
+			if (sk_is_mptcp(sk))
+				mptcp_handle_ipv6_mapped(sk, false);
 			sk->sk_backlog_rcv = tcp_v6_do_rcv;
 #ifdef CONFIG_TCP_MD5SIG
 			tp->af_specific = &tcp_sock_ipv6_specific;
@@ -532,15 +537,22 @@ static void tcp_v6_reqsk_destructor(struct request_sock *req)
 
 #ifdef CONFIG_TCP_MD5SIG
 static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
-						   const struct in6_addr *addr)
+						   const struct in6_addr *addr,
+						   int l3index)
 {
-	return tcp_md5_do_lookup(sk, (union tcp_md5_addr *)addr, AF_INET6);
+	return tcp_md5_do_lookup(sk, l3index,
+				 (union tcp_md5_addr *)addr, AF_INET6);
 }
 
 static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk,
 						const struct sock *addr_sk)
 {
-	return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr);
+	int l3index;
+
+	l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
+						 addr_sk->sk_bound_dev_if);
+	return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr,
+				    l3index);
 }
 
 static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
@@ -548,6 +560,7 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
 {
 	struct tcp_md5sig cmd;
 	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
+	int l3index = 0;
 	u8 prefixlen;
 
 	if (optlen < sizeof(cmd))
@@ -569,12 +582,30 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
 		prefixlen = ipv6_addr_v4mapped(&sin6->sin6_addr) ? 32 : 128;
 	}
 
+	if (optname == TCP_MD5SIG_EXT &&
+	    cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) {
+		struct net_device *dev;
+
+		rcu_read_lock();
+		dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex);
+		if (dev && netif_is_l3_master(dev))
+			l3index = dev->ifindex;
+		rcu_read_unlock();
+
+		/* ok to reference set/not set outside of rcu;
+		 * right now device MUST be an L3 master
+		 */
+		if (!dev || !l3index)
+			return -EINVAL;
+	}
+
 	if (!cmd.tcpm_keylen) {
 		if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 			return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
-					      AF_INET, prefixlen);
+					      AF_INET, prefixlen,
+					      l3index);
 		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
-				      AF_INET6, prefixlen);
+				      AF_INET6, prefixlen, l3index);
 	}
 
 	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
@@ -582,12 +613,13 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
 
 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
-				      AF_INET, prefixlen, cmd.tcpm_key,
-				      cmd.tcpm_keylen, GFP_KERNEL);
+				      AF_INET, prefixlen, l3index,
+				      cmd.tcpm_key, cmd.tcpm_keylen,
+				      GFP_KERNEL);
 
 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
-			      AF_INET6, prefixlen, cmd.tcpm_key,
-			      cmd.tcpm_keylen, GFP_KERNEL);
+			      AF_INET6, prefixlen, l3index,
+			      cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
 }
 
 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
@@ -698,17 +730,23 @@ clear_hash_noput:
 #endif
 
 static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
-				    const struct sk_buff *skb)
+				    const struct sk_buff *skb,
+				    int dif, int sdif)
 {
 #ifdef CONFIG_TCP_MD5SIG
 	const __u8 *hash_location = NULL;
 	struct tcp_md5sig_key *hash_expected;
 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 	const struct tcphdr *th = tcp_hdr(skb);
-	int genhash;
+	int genhash, l3index;
 	u8 newhash[16];
 
-	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
+	/* sdif set, means packet ingressed via a device
+	 * in an L3 domain and dif is set to the l3mdev
+	 */
+	l3index = sdif ? dif : 0;
+
+	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr, l3index);
 	hash_location = tcp_parse_md5sig_option(th);
 
 	/* We've parsed the options - do we have a hash? */
@@ -732,10 +770,10 @@ static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
 
 	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
-		net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u\n",
+		net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u L3 index %d\n",
 				     genhash ? "failed" : "mismatch",
 				     &ip6h->saddr, ntohs(th->source),
-				     &ip6h->daddr, ntohs(th->dest));
+				     &ip6h->daddr, ntohs(th->dest), l3index);
 		return true;
 	}
 #endif
@@ -785,7 +823,7 @@ struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
 	.syn_ack_timeout =	tcp_syn_ack_timeout,
 };
 
-static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
+const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 	.mss_clamp	=	IPV6_MIN_MTU - sizeof(struct tcphdr) -
 				sizeof(struct ipv6hdr),
 #ifdef CONFIG_TCP_MD5SIG
@@ -951,8 +989,18 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 	rcu_read_lock();
 	hash_location = tcp_parse_md5sig_option(th);
 	if (sk && sk_fullsock(sk)) {
-		key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr);
+		int l3index;
+
+		/* sdif set, means packet ingressed via a device
+		 * in an L3 domain and inet_iif is set to it.
+		 */
+		l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
+		key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index);
 	} else if (hash_location) {
+		int dif = tcp_v6_iif_l3_slave(skb);
+		int sdif = tcp_v6_sdif(skb);
+		int l3index;
+
 		/*
 		 * active side is lost. Try to find listening socket through
 		 * source port, and then find md5 key through listening socket.
@@ -964,13 +1012,16 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
 					   &tcp_hashinfo, NULL, 0,
 					   &ipv6h->saddr,
 					   th->source, &ipv6h->daddr,
-					   ntohs(th->source),
-					   tcp_v6_iif_l3_slave(skb),
-					   tcp_v6_sdif(skb));
+					   ntohs(th->source), dif, sdif);
 		if (!sk1)
 			goto out;
 
-		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
+		/* sdif set, means packet ingressed via a device
+		 * in an L3 domain and dif is set to it.
+		 */
+		l3index = tcp_v6_sdif(skb) ? dif : 0;
+
+		key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index);
 		if (!key)
 			goto out;
 
@@ -1040,6 +1091,10 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 				  struct request_sock *req)
 {
+	int l3index;
+
+	l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
+
 	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
 	 */
@@ -1054,7 +1109,7 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 			tcp_time_stamp_raw() + tcp_rsk(req)->ts_off,
 			req->ts_recent, sk->sk_bound_dev_if,
-			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr),
+			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr, l3index),
 			0, 0, sk->sk_priority);
 }
 
@@ -1126,6 +1181,7 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
 	struct sock *newsk;
 #ifdef CONFIG_TCP_MD5SIG
 	struct tcp_md5sig_key *key;
+	int l3index;
 #endif
 	struct flowi6 fl6;
 
@@ -1151,6 +1207,8 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
 		newnp->saddr = newsk->sk_v6_rcv_saddr;
 
 		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
+		if (sk_is_mptcp(newsk))
+			mptcp_handle_ipv6_mapped(newsk, true);
 		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
 #ifdef CONFIG_TCP_MD5SIG
 		newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
@@ -1269,8 +1327,10 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
 
 #ifdef CONFIG_TCP_MD5SIG
+	l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
+
 	/* Copy over the MD5 key from the original socket */
-	key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr);
+	key = tcp_v6_md5_do_lookup(sk, &newsk->sk_v6_daddr, l3index);
 	if (key) {
 		/* We're using one, so create a matching key
 		 * on the newsk structure. If we fail to get
@@ -1278,7 +1338,7 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
 		 * across. Shucks.
 		 */
 		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
-			       AF_INET6, 128, key->key, key->keylen,
+			       AF_INET6, 128, l3index, key->key, key->keylen,
 			       sk_gfp_mask(sk, GFP_ATOMIC));
 	}
 #endif
@@ -1480,6 +1540,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 {
 	struct sk_buff *skb_to_free;
 	int sdif = inet6_sdif(skb);
+	int dif = inet6_iif(skb);
 	const struct tcphdr *th;
 	const struct ipv6hdr *hdr;
 	bool refcounted;
@@ -1528,7 +1589,7 @@ process:
 		struct sock *nsk;
 
 		sk = req->rsk_listener;
-		if (tcp_v6_inbound_md5_hash(sk, skb)) {
+		if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif)) {
 			sk_drops_add(sk, skb);
 			reqsk_put(req);
 			goto discard_it;
@@ -1583,7 +1644,7 @@ process:
 	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
 		goto discard_and_relse;
 
-	if (tcp_v6_inbound_md5_hash(sk, skb))
+	if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif))
 		goto discard_and_relse;
 
 	if (tcp_filter(sk, skb))
@@ -1739,7 +1800,7 @@ static struct timewait_sock_ops tcp6_timewait_sock_ops = {
 	.twsk_destructor = tcp_twsk_destructor,
 };
 
-static const struct inet_connection_sock_af_ops ipv6_specific = {
+const struct inet_connection_sock_af_ops ipv6_specific = {
 	.queue_xmit	   = inet6_csk_xmit,
 	.send_check	   = tcp_v6_send_check,
 	.rebuild_header	   = inet6_sk_rebuild_header,
@@ -2108,9 +2169,16 @@ int __init tcpv6_init(void)
 	ret = register_pernet_subsys(&tcpv6_net_ops);
 	if (ret)
 		goto out_tcpv6_protosw;
+
+	ret = mptcpv6_init();
+	if (ret)
+		goto out_tcpv6_pernet_subsys;
+
 out:
 	return ret;
 
+out_tcpv6_pernet_subsys:
+	unregister_pernet_subsys(&tcpv6_net_ops);
 out_tcpv6_protosw:
 	inet6_unregister_protosw(&tcpv6_protosw);
 out_tcpv6_protocol:
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 9fec580c968e..5dc439a391fe 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -690,8 +690,7 @@ static int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 
 	__skb_push(skb, -skb_mac_offset(skb));
 	segs = udp_rcv_segment(sk, skb, false);
-	for (skb = segs; skb; skb = next) {
-		next = skb->next;
+	skb_list_walk_safe(segs, skb, next) {
 		__skb_pull(skb, skb_transport_offset(skb));
 
 		ret = udpv6_queue_rcv_one_skb(sk, skb);
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index 64b8f05d6735..584157a07759 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -115,8 +115,10 @@ INDIRECT_CALLABLE_SCOPE
 struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb)
 {
 	struct udphdr *uh = udp_gro_udphdr(skb);
+	struct sk_buff *pp;
+	struct sock *sk;
 
-	if (unlikely(!uh) || !static_branch_unlikely(&udpv6_encap_needed_key))
+	if (unlikely(!uh))
 		goto flush;
 
 	/* Don't bother verifying checksum if we're going to flush anyway. */
@@ -127,12 +129,16 @@ struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb)
 						 ip6_gro_compute_pseudo))
 		goto flush;
 	else if (uh->check)
-		skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
+		skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
 					     ip6_gro_compute_pseudo);
 
 skip:
 	NAPI_GRO_CB(skb)->is_ipv6 = 1;
-	return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb);
+	rcu_read_lock();
+	sk = static_branch_unlikely(&udpv6_encap_needed_key) ? udp6_lib_lookup_skb(skb, uh->source, uh->dest) : NULL;
+	pp = udp_gro_receive(head, skb, uh, sk);
+	rcu_read_unlock();
+	return pp;
 
 flush:
 	NAPI_GRO_CB(skb)->flush = 1;
@@ -144,6 +150,23 @@ INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff)
 	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 	struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 
+	if (NAPI_GRO_CB(skb)->is_flist) {
+		uh->len = htons(skb->len - nhoff);
+
+		skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
+		skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
+
+		if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
+			if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
+				skb->csum_level++;
+		} else {
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+			skb->csum_level = 0;
+		}
+
+		return 0;
+	}
+
 	if (uh->check)
 		uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr,
 					  &ipv6h->daddr, 0);