diff --git a/include/net/route.h b/include/net/route.h
index a36ae42..47eb25a 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -215,7 +215,10 @@
 	return ip_route_input_common(skb, dst, src, tos, devin, true);
 }
 
-extern void		ip_rt_send_redirect(struct sk_buff *skb);
+extern void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
+			     int oif, u32 mark, u8 protocol, int flow_flags);
+extern void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu);
+extern void ip_rt_send_redirect(struct sk_buff *skb);
 
 extern unsigned int		inet_addr_type(struct net *net, __be32 addr);
 extern unsigned int		inet_dev_addr_type(struct net *net, const struct net_device *dev, __be32 addr);
diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index e8f2617..916d5ec 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -408,6 +408,7 @@
 		return;
 	pr_debug("pmtu discovery on SA AH/%08x/%08x\n",
 		 ntohl(ah->spi), ntohl(iph->daddr));
+	ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_AH, 0);
 	xfrm_state_put(x);
 }
 
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index cb982a6..7b95b49 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -494,6 +494,7 @@
 		return;
 	NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
 		 ntohl(esph->spi), ntohl(iph->daddr));
+	ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
 	xfrm_state_put(x);
 }
 
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index f49047b..594cec3 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -516,9 +516,6 @@
 		case ICMP_PORT_UNREACH:
 			/* Impossible event. */
 			return;
-		case ICMP_FRAG_NEEDED:
-			/* Soft state for pmtu is maintained by IP core. */
-			return;
 		default:
 			/* All others are translated to HOST_UNREACH.
 			   rfc2003 contains "deep thoughts" about NET_UNREACH,
@@ -538,7 +535,16 @@
 				flags & GRE_KEY ?
 				*(((__be32 *)p) + (grehlen / 4) - 1) : 0,
 				p[1]);
-	if (t == NULL || t->parms.iph.daddr == 0 ||
+	if (t == NULL)
+		goto out;
+
+	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
+		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
+				 t->parms.link, 0, IPPROTO_GRE, 0);
+		goto out;
+	}
+
+	if (t->parms.iph.daddr == 0 ||
 	    ipv4_is_multicast(t->parms.iph.daddr))
 		goto out;
 
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index 63b64c4..b913754 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -42,6 +42,7 @@
 		return;
 	NETDEBUG(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI4\n",
 		 spi, &iph->daddr);
+	ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_COMP, 0);
 	xfrm_state_put(x);
 }
 
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 2d0f99b..715338a 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -348,9 +348,6 @@
 		case ICMP_PORT_UNREACH:
 			/* Impossible event. */
 			return 0;
-		case ICMP_FRAG_NEEDED:
-			/* Soft state for pmtu is maintained by IP core. */
-			return 0;
 		default:
 			/* All others are translated to HOST_UNREACH.
 			   rfc2003 contains "deep thoughts" about NET_UNREACH,
@@ -369,7 +366,17 @@
 
 	rcu_read_lock();
 	t = ipip_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
-	if (t == NULL || t->parms.iph.daddr == 0)
+	if (t == NULL)
+		goto out;
+
+	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
+		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
+				 t->dev->ifindex, 0, IPPROTO_IPIP, 0);
+		err = 0;
+		goto out;
+	}
+
+	if (t->parms.iph.daddr == 0)
 		goto out;
 
 	err = 0;
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 2c00e8b..340fcf2 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -371,6 +371,7 @@
 		break;
 	case ICMP_DEST_UNREACH:
 		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
+			ipv4_sk_update_pmtu(skb, sk, info);
 			if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
 				err = EMSGSIZE;
 				harderr = 1;
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 4032b81..659ddfb 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -216,6 +216,9 @@
 	int err = 0;
 	int harderr = 0;
 
+	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
+		ipv4_sk_update_pmtu(skb, sk, info);
+
 	/* Report error on raw socket, if:
 	   1. User requested ip_recverr.
 	   2. Socket is connected (otherwise the error indication
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 655506a..41df529 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1711,6 +1711,34 @@
 	}
 }
 
+void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
+		      int oif, u32 mark, u8 protocol, int flow_flags)
+{
+	const struct iphdr *iph = (const struct iphdr *)skb->data;
+	struct flowi4 fl4;
+	struct rtable *rt;
+
+	flowi4_init_output(&fl4, oif, mark, RT_TOS(iph->tos), RT_SCOPE_UNIVERSE,
+			   protocol, flow_flags | FLOWI_FLAG_PRECOW_METRICS,
+			   iph->daddr, iph->saddr, 0, 0);
+	rt = __ip_route_output_key(net, &fl4);
+	if (!IS_ERR(rt)) {
+		ip_rt_update_pmtu(&rt->dst, mtu);
+		ip_rt_put(rt);
+	}
+}
+EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
+
+void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+
+	return ipv4_update_pmtu(skb, sock_net(sk), mtu,
+				sk->sk_bound_dev_if, sk->sk_mark,
+				inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,
+				inet_sk_flowi_flags(sk));
+}
+EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
 
 static void ipv4_validate_peer(struct rtable *rt)
 {
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index eaca736..db017ef 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -615,6 +615,7 @@
 		break;
 	case ICMP_DEST_UNREACH:
 		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
+			ipv4_sk_update_pmtu(skb, sk, info);
 			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
 				err = EMSGSIZE;
 				harderr = 1;
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 6041571..49aea94 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -527,9 +527,6 @@
 		case ICMP_PORT_UNREACH:
 			/* Impossible event. */
 			return 0;
-		case ICMP_FRAG_NEEDED:
-			/* Soft state for pmtu is maintained by IP core. */
-			return 0;
 		default:
 			/* All others are translated to HOST_UNREACH.
 			   rfc2003 contains "deep thoughts" about NET_UNREACH,
@@ -551,7 +548,17 @@
 				skb->dev,
 				iph->daddr,
 				iph->saddr);
-	if (t == NULL || t->parms.iph.daddr == 0)
+	if (t == NULL)
+		goto out;
+
+	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
+		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
+				 t->dev->ifindex, 0, IPPROTO_IPV6, 0);
+		err = 0;
+		goto out;
+	}
+
+	if (t->parms.iph.daddr == 0)
 		goto out;
 
 	err = 0;