net: Convert protocol error handlers from void to int

We'll need this to handle ICMP errors for tunnels without a sending socket
(i.e. FoU and GUE). There, we might have to look up different types of IP
tunnels, registered as network protocols, before we get a match, so we
want this for the error handlers of IPPROTO_IPIP and IPPROTO_IPV6 in both
inet_protos and inet6_protos. These error codes will be used in the next
patch.

For consistency, return sensible error codes in protocol error handlers
whenever handlers can't handle errors because, even if valid, they don't
match a protocol or any of its states.

This has no effect on existing error handling paths.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/icmp.h

@@ -41,7 +41,7 @@ struct net;
 
 void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info);
 int icmp_rcv(struct sk_buff *skb);
-void icmp_err(struct sk_buff *skb, u32 info);
+int icmp_err(struct sk_buff *skb, u32 info);
 int icmp_init(void);
 void icmp_out_count(struct net *net, unsigned char type);
 

include/net/protocol.h

@@ -42,7 +42,10 @@ struct net_protocol {
 	int			(*early_demux)(struct sk_buff *skb);
 	int			(*early_demux_handler)(struct sk_buff *skb);
 	int			(*handler)(struct sk_buff *skb);
-	void			(*err_handler)(struct sk_buff *skb, u32 info);
+
+	/* This returns an error if we weren't able to handle the error. */
+	int			(*err_handler)(struct sk_buff *skb, u32 info);
+
 	unsigned int		no_policy:1,
 				netns_ok:1,
 				/* does the protocol do more stringent
@@ -58,10 +61,12 @@ struct inet6_protocol {
 	void    (*early_demux_handler)(struct sk_buff *skb);
 	int	(*handler)(struct sk_buff *skb);
 
-	void	(*err_handler)(struct sk_buff *skb,
+	/* This returns an error if we weren't able to handle the error. */
+	int	(*err_handler)(struct sk_buff *skb,
 			       struct inet6_skb_parm *opt,
 			       u8 type, u8 code, int offset,
 			       __be32 info);
+
 	unsigned int	flags;	/* INET6_PROTO_xxx */
 };
 

include/net/sctp/sctp.h

@@ -151,7 +151,7 @@ int sctp_primitive_RECONF(struct net *net, struct sctp_association *asoc,
  * sctp/input.c
  */
 int sctp_rcv(struct sk_buff *skb);
-void sctp_v4_err(struct sk_buff *skb, u32 info);
+int sctp_v4_err(struct sk_buff *skb, u32 info);
 void sctp_hash_endpoint(struct sctp_endpoint *);
 void sctp_unhash_endpoint(struct sctp_endpoint *);
 struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,

include/net/tcp.h

@@ -313,7 +313,7 @@ extern struct proto tcp_prot;
 
 void tcp_tasklet_init(void);
 
-void tcp_v4_err(struct sk_buff *skb, u32);
+int tcp_v4_err(struct sk_buff *skb, u32);
 
 void tcp_shutdown(struct sock *sk, int how);
 

include/net/udp.h

@@ -283,7 +283,7 @@ bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
 int udp_get_port(struct sock *sk, unsigned short snum,
 		 int (*saddr_cmp)(const struct sock *,
 				  const struct sock *));
-void udp_err(struct sk_buff *, u32);
+int udp_err(struct sk_buff *, u32);
 int udp_abort(struct sock *sk, int err);
 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
 int udp_push_pending_frames(struct sock *sk);

net/dccp/ipv4.c

@@ -231,7 +231,7 @@ EXPORT_SYMBOL(dccp_req_err);
  * check at all. A more general error queue to queue errors for later handling
  * is probably better.
  */
-static void dccp_v4_err(struct sk_buff *skb, u32 info)
+static int dccp_v4_err(struct sk_buff *skb, u32 info)
 {
 	const struct iphdr *iph = (struct iphdr *)skb->data;
 	const u8 offset = iph->ihl << 2;
@@ -259,16 +259,18 @@ static void dccp_v4_err(struct sk_buff *skb, u32 info)
 				       inet_iif(skb), 0);
 	if (!sk) {
 		__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
-		return;
+		return -ENOENT;
 	}
 
 	if (sk->sk_state == DCCP_TIME_WAIT) {
 		inet_twsk_put(inet_twsk(sk));
-		return;
+		return 0;
 	}
 	seq = dccp_hdr_seq(dh);
-	if (sk->sk_state == DCCP_NEW_SYN_RECV)
-		return dccp_req_err(sk, seq);
+	if (sk->sk_state == DCCP_NEW_SYN_RECV) {
+		dccp_req_err(sk, seq);
+		return 0;
+	}
 
 	bh_lock_sock(sk);
 	/* If too many ICMPs get dropped on busy
@@ -357,6 +359,7 @@ static void dccp_v4_err(struct sk_buff *skb, u32 info)
 out:
 	bh_unlock_sock(sk);
 	sock_put(sk);
+	return 0;
 }
 
 static inline __sum16 dccp_v4_csum_finish(struct sk_buff *skb,

net/dccp/ipv6.c

@@ -68,7 +68,7 @@ static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
 
 }
 
-static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			u8 type, u8 code, int offset, __be32 info)
 {
 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
@@ -96,16 +96,18 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	if (!sk) {
 		__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
 				  ICMP6_MIB_INERRORS);
-		return;
+		return -ENOENT;
 	}
 
 	if (sk->sk_state == DCCP_TIME_WAIT) {
 		inet_twsk_put(inet_twsk(sk));
-		return;
+		return 0;
 	}
 	seq = dccp_hdr_seq(dh);
-	if (sk->sk_state == DCCP_NEW_SYN_RECV)
-		return dccp_req_err(sk, seq);
+	if (sk->sk_state == DCCP_NEW_SYN_RECV) {
+		dccp_req_err(sk, seq);
+		return 0;
+	}
 
 	bh_lock_sock(sk);
 	if (sock_owned_by_user(sk))
@@ -183,6 +185,7 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 out:
 	bh_unlock_sock(sk);
 	sock_put(sk);
+	return 0;
 }
 
 

net/ipv4/gre_demux.c

@@ -151,20 +151,25 @@ static int gre_rcv(struct sk_buff *skb)
 	return NET_RX_DROP;
 }
 
-static void gre_err(struct sk_buff *skb, u32 info)
+static int gre_err(struct sk_buff *skb, u32 info)
 {
 	const struct gre_protocol *proto;
 	const struct iphdr *iph = (const struct iphdr *)skb->data;
 	u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
+	int err = 0;
 
 	if (ver >= GREPROTO_MAX)
-		return;
+		return -EINVAL;
 
 	rcu_read_lock();
 	proto = rcu_dereference(gre_proto[ver]);
 	if (proto && proto->err_handler)
 		proto->err_handler(skb, info);
+	else
+		err = -EPROTONOSUPPORT;
 	rcu_read_unlock();
+
+	return err;
 }
 
 static const struct net_protocol net_gre_protocol = {

net/ipv4/icmp.c

@@ -1079,7 +1079,7 @@ int icmp_rcv(struct sk_buff *skb)
 	goto drop;
 }
 
-void icmp_err(struct sk_buff *skb, u32 info)
+int icmp_err(struct sk_buff *skb, u32 info)
 {
 	struct iphdr *iph = (struct iphdr *)skb->data;
 	int offset = iph->ihl<<2;
@@ -1094,13 +1094,15 @@ void icmp_err(struct sk_buff *skb, u32 info)
 	 */
 	if (icmph->type != ICMP_ECHOREPLY) {
 		ping_err(skb, offset, info);
-		return;
+		return 0;
 	}
 
 	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)
 		ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ICMP);
 	else if (type == ICMP_REDIRECT)
 		ipv4_redirect(skb, net, 0, IPPROTO_ICMP);
+
+	return 0;
 }
 
 /*

net/ipv4/ip_gre.c

@@ -121,7 +121,7 @@ static unsigned int ipgre_net_id __read_mostly;
 static unsigned int gre_tap_net_id __read_mostly;
 static unsigned int erspan_net_id __read_mostly;
 
-static void ipgre_err(struct sk_buff *skb, u32 info,
+static int ipgre_err(struct sk_buff *skb, u32 info,
 		     const struct tnl_ptk_info *tpi)
 {
 
@@ -146,17 +146,32 @@ static void ipgre_err(struct sk_buff *skb, u32 info,
 	unsigned int data_len = 0;
 	struct ip_tunnel *t;
 
+	if (tpi->proto == htons(ETH_P_TEB))
+		itn = net_generic(net, gre_tap_net_id);
+	else if (tpi->proto == htons(ETH_P_ERSPAN) ||
+		 tpi->proto == htons(ETH_P_ERSPAN2))
+		itn = net_generic(net, erspan_net_id);
+	else
+		itn = net_generic(net, ipgre_net_id);
+
+	iph = (const struct iphdr *)(icmp_hdr(skb) + 1);
+	t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
+			     iph->daddr, iph->saddr, tpi->key);
+
+	if (!t)
+		return -ENOENT;
+
 	switch (type) {
 	default:
 	case ICMP_PARAMETERPROB:
-		return;
+		return 0;
 
 	case ICMP_DEST_UNREACH:
 		switch (code) {
 		case ICMP_SR_FAILED:
 		case ICMP_PORT_UNREACH:
 			/* Impossible event. */
-			return;
+			return 0;
 		default:
 			/* All others are translated to HOST_UNREACH.
 			   rfc2003 contains "deep thoughts" about NET_UNREACH,
@@ -168,7 +183,7 @@ static void ipgre_err(struct sk_buff *skb, u32 info,
 
 	case ICMP_TIME_EXCEEDED:
 		if (code != ICMP_EXC_TTL)
-			return;
+			return 0;
 		data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
 		break;
 
@@ -176,40 +191,27 @@ static void ipgre_err(struct sk_buff *skb, u32 info,
 		break;
 	}
 
-	if (tpi->proto == htons(ETH_P_TEB))
-		itn = net_generic(net, gre_tap_net_id);
-	else if (tpi->proto == htons(ETH_P_ERSPAN) ||
-		 tpi->proto == htons(ETH_P_ERSPAN2))
-		itn = net_generic(net, erspan_net_id);
-	else
-		itn = net_generic(net, ipgre_net_id);
-
-	iph = (const struct iphdr *)(icmp_hdr(skb) + 1);
-	t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
-			     iph->daddr, iph->saddr, tpi->key);
-
-	if (!t)
-		return;
-
 #if IS_ENABLED(CONFIG_IPV6)
        if (tpi->proto == htons(ETH_P_IPV6) &&
            !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4 + tpi->hdr_len,
 				       type, data_len))
-               return;
+               return 0;
 #endif
 
 	if (t->parms.iph.daddr == 0 ||
 	    ipv4_is_multicast(t->parms.iph.daddr))
-		return;
+		return 0;
 
 	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
-		return;
+		return 0;
 
 	if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 		t->err_count++;
 	else
 		t->err_count = 1;
 	t->err_time = jiffies;
+
+	return 0;
 }
 
 static void gre_err(struct sk_buff *skb, u32 info)

net/ipv4/ipip.c

@@ -140,6 +140,13 @@ static int ipip_err(struct sk_buff *skb, u32 info)
 	struct ip_tunnel *t;
 	int err = 0;
 
+	t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
+			     iph->daddr, iph->saddr, 0);
+	if (!t) {
+		err = -ENOENT;
+		goto out;
+	}
+
 	switch (type) {
 	case ICMP_DEST_UNREACH:
 		switch (code) {
@@ -167,13 +174,6 @@ static int ipip_err(struct sk_buff *skb, u32 info)
 		goto out;
 	}
 
-	t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
-			     iph->daddr, iph->saddr, 0);
-	if (!t) {
-		err = -ENOENT;
-		goto out;
-	}
-
 	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 		ipv4_update_pmtu(skb, net, info, t->parms.link, iph->protocol);
 		goto out;

net/ipv4/tcp_ipv4.c

@@ -423,7 +423,7 @@ EXPORT_SYMBOL(tcp_req_err);
  *
  */
 
-void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
+int tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 {
 	const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
 	struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
@@ -446,20 +446,21 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 				       inet_iif(icmp_skb), 0);
 	if (!sk) {
 		__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
-		return;
+		return -ENOENT;
 	}
 	if (sk->sk_state == TCP_TIME_WAIT) {
 		inet_twsk_put(inet_twsk(sk));
-		return;
+		return 0;
 	}
 	seq = ntohl(th->seq);
-	if (sk->sk_state == TCP_NEW_SYN_RECV)
-		return tcp_req_err(sk, seq,
-				  type == ICMP_PARAMETERPROB ||
+	if (sk->sk_state == TCP_NEW_SYN_RECV) {
+		tcp_req_err(sk, seq, type == ICMP_PARAMETERPROB ||
 				     type == ICMP_TIME_EXCEEDED ||
 				     (type == ICMP_DEST_UNREACH &&
 				      (code == ICMP_NET_UNREACH ||
 				       code == ICMP_HOST_UNREACH)));
+		return 0;
+	}
 
 	bh_lock_sock(sk);
 	/* If too many ICMPs get dropped on busy
@@ -613,6 +614,7 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
 out:
 	bh_unlock_sock(sk);
 	sock_put(sk);
+	return 0;
 }
 
 void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)

net/ipv4/tunnel4.c

@@ -149,34 +149,40 @@ static int tunnelmpls4_rcv(struct sk_buff *skb)
 }
 #endif
 
-static void tunnel4_err(struct sk_buff *skb, u32 info)
+static int tunnel4_err(struct sk_buff *skb, u32 info)
 {
 	struct xfrm_tunnel *handler;
 
 	for_each_tunnel_rcu(tunnel4_handlers, handler)
 		if (!handler->err_handler(skb, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 
 #if IS_ENABLED(CONFIG_IPV6)
-static void tunnel64_err(struct sk_buff *skb, u32 info)
+static int tunnel64_err(struct sk_buff *skb, u32 info)
 {
 	struct xfrm_tunnel *handler;
 
 	for_each_tunnel_rcu(tunnel64_handlers, handler)
 		if (!handler->err_handler(skb, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 #endif
 
 #if IS_ENABLED(CONFIG_MPLS)
-static void tunnelmpls4_err(struct sk_buff *skb, u32 info)
+static int tunnelmpls4_err(struct sk_buff *skb, u32 info)
 {
 	struct xfrm_tunnel *handler;
 
 	for_each_tunnel_rcu(tunnelmpls4_handlers, handler)
 		if (!handler->err_handler(skb, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 #endif
 

net/ipv4/udp.c

@@ -650,7 +650,7 @@ static struct sock *__udp4_lib_err_encap(struct net *net,
  * to find the appropriate port.
  */
 
-void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
+int __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
 {
 	struct inet_sock *inet;
 	const struct iphdr *iph = (const struct iphdr *)skb->data;
@@ -673,7 +673,7 @@ void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
 
 		if (!sk) {
 			__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
-			return;
+			return -ENOENT;
 		}
 		tunnel = true;
 	}
@@ -731,12 +731,12 @@ void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
 	sk->sk_err = err;
 	sk->sk_error_report(sk);
 out:
-	return;
+	return 0;
 }
 
-void udp_err(struct sk_buff *skb, u32 info)
+int udp_err(struct sk_buff *skb, u32 info)
 {
-	__udp4_lib_err(skb, info, &udp_table);
+	return __udp4_lib_err(skb, info, &udp_table);
 }
 
 /*

net/ipv4/udp_impl.h

@@ -7,7 +7,7 @@
 #include <net/inet_common.h>
 
 int __udp4_lib_rcv(struct sk_buff *, struct udp_table *, int);
-void __udp4_lib_err(struct sk_buff *, u32, struct udp_table *);
+int __udp4_lib_err(struct sk_buff *, u32, struct udp_table *);
 
 int udp_v4_get_port(struct sock *sk, unsigned short snum);
 

net/ipv4/udplite.c

@@ -25,9 +25,9 @@ static int udplite_rcv(struct sk_buff *skb)
 	return __udp4_lib_rcv(skb, &udplite_table, IPPROTO_UDPLITE);
 }
 
-static void udplite_err(struct sk_buff *skb, u32 info)
+static int udplite_err(struct sk_buff *skb, u32 info)
 {
-	__udp4_lib_err(skb, info, &udplite_table);
+	return __udp4_lib_err(skb, info, &udplite_table);
 }
 
 static const struct net_protocol udplite_protocol = {

net/ipv4/xfrm4_protocol.c

@@ -106,13 +106,15 @@ static int xfrm4_esp_rcv(struct sk_buff *skb)
 	return 0;
 }
 
-static void xfrm4_esp_err(struct sk_buff *skb, u32 info)
+static int xfrm4_esp_err(struct sk_buff *skb, u32 info)
 {
 	struct xfrm4_protocol *handler;
 
 	for_each_protocol_rcu(esp4_handlers, handler)
 		if (!handler->err_handler(skb, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 
 static int xfrm4_ah_rcv(struct sk_buff *skb)
@@ -132,13 +134,15 @@ static int xfrm4_ah_rcv(struct sk_buff *skb)
 	return 0;
 }
 
-static void xfrm4_ah_err(struct sk_buff *skb, u32 info)
+static int xfrm4_ah_err(struct sk_buff *skb, u32 info)
 {
 	struct xfrm4_protocol *handler;
 
 	for_each_protocol_rcu(ah4_handlers, handler)
 		if (!handler->err_handler(skb, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 
 static int xfrm4_ipcomp_rcv(struct sk_buff *skb)
@@ -158,13 +162,15 @@ static int xfrm4_ipcomp_rcv(struct sk_buff *skb)
 	return 0;
 }
 
-static void xfrm4_ipcomp_err(struct sk_buff *skb, u32 info)
+static int xfrm4_ipcomp_err(struct sk_buff *skb, u32 info)
 {
 	struct xfrm4_protocol *handler;
 
 	for_each_protocol_rcu(ipcomp4_handlers, handler)
 		if (!handler->err_handler(skb, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 
 static const struct net_protocol esp4_protocol = {

net/ipv6/icmp.c

@@ -84,7 +84,7 @@ static inline struct sock *icmpv6_sk(struct net *net)
 	return net->ipv6.icmp_sk[smp_processor_id()];
 }
 
-static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		       u8 type, u8 code, int offset, __be32 info)
 {
 	/* icmpv6_notify checks 8 bytes can be pulled, icmp6hdr is 8 bytes */
@@ -100,6 +100,8 @@ static void icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	if (!(type & ICMPV6_INFOMSG_MASK))
 		if (icmp6->icmp6_type == ICMPV6_ECHO_REQUEST)
 			ping_err(skb, offset, ntohl(info));
+
+	return 0;
 }
 
 static int icmpv6_rcv(struct sk_buff *skb);

net/ipv6/ip6_gre.c

@@ -423,7 +423,7 @@ static void ip6gre_tunnel_uninit(struct net_device *dev)
 }
 
 
-static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		       u8 type, u8 code, int offset, __be32 info)
 {
 	struct net *net = dev_net(skb->dev);
@@ -433,13 +433,13 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 
 	if (gre_parse_header(skb, &tpi, NULL, htons(ETH_P_IPV6),
 			     offset) < 0)
-		return;
+		return -EINVAL;
 
 	ipv6h = (const struct ipv6hdr *)skb->data;
 	t = ip6gre_tunnel_lookup(skb->dev, &ipv6h->daddr, &ipv6h->saddr,
 				 tpi.key, tpi.proto);
 	if (!t)
-		return;
+		return -ENOENT;
 
 	switch (type) {
 		struct ipv6_tlv_tnl_enc_lim *tel;
@@ -449,14 +449,14 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 				    t->parms.name);
 		if (code != ICMPV6_PORT_UNREACH)
 			break;
-		return;
+		return 0;
 	case ICMPV6_TIME_EXCEED:
 		if (code == ICMPV6_EXC_HOPLIMIT) {
 			net_dbg_ratelimited("%s: Too small hop limit or routing loop in tunnel!\n",
 					    t->parms.name);
 			break;
 		}
-		return;
+		return 0;
 	case ICMPV6_PARAMPROB:
 		teli = 0;
 		if (code == ICMPV6_HDR_FIELD)
@@ -472,14 +472,14 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			net_dbg_ratelimited("%s: Recipient unable to parse tunneled packet!\n",
 					    t->parms.name);
 		}
-		return;
+		return 0;
 	case ICMPV6_PKT_TOOBIG:
 		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
-		return;
+		return 0;
 	case NDISC_REDIRECT:
 		ip6_redirect(skb, net, skb->dev->ifindex, 0,
 			     sock_net_uid(net, NULL));
-		return;
+		return 0;
 	}
 
 	if (time_before(jiffies, t->err_time + IP6TUNNEL_ERR_TIMEO))
@@ -487,6 +487,8 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	else
 		t->err_count = 1;
 	t->err_time = jiffies;
+
+	return 0;
 }
 
 static int ip6gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)

net/ipv6/tcp_ipv6.c

@@ -349,7 +349,7 @@ static void tcp_v6_mtu_reduced(struct sock *sk)
 	}
 }
 
-static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		u8 type, u8 code, int offset, __be32 info)
 {
 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
@@ -371,17 +371,19 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	if (!sk) {
 		__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
 				  ICMP6_MIB_INERRORS);
-		return;
+		return -ENOENT;
 	}
 
 	if (sk->sk_state == TCP_TIME_WAIT) {
 		inet_twsk_put(inet_twsk(sk));
-		return;
+		return 0;
 	}
 	seq = ntohl(th->seq);
 	fatal = icmpv6_err_convert(type, code, &err);
-	if (sk->sk_state == TCP_NEW_SYN_RECV)
-		return tcp_req_err(sk, seq, fatal);
+	if (sk->sk_state == TCP_NEW_SYN_RECV) {
+		tcp_req_err(sk, seq, fatal);
+		return 0;
+	}
 
 	bh_lock_sock(sk);
 	if (sock_owned_by_user(sk) && type != ICMPV6_PKT_TOOBIG)
@@ -467,6 +469,7 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 out:
 	bh_unlock_sock(sk);
 	sock_put(sk);
+	return 0;
 }
 
 

net/ipv6/tunnel6.c

@@ -134,24 +134,28 @@ static int tunnel46_rcv(struct sk_buff *skb)
 	return 0;
 }
 
-static void tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			u8 type, u8 code, int offset, __be32 info)
 {
 	struct xfrm6_tunnel *handler;
 
 	for_each_tunnel_rcu(tunnel6_handlers, handler)
 		if (!handler->err_handler(skb, opt, type, code, offset, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 
-static void tunnel46_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int tunnel46_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			 u8 type, u8 code, int offset, __be32 info)
 {
 	struct xfrm6_tunnel *handler;
 
 	for_each_tunnel_rcu(tunnel46_handlers, handler)
 		if (!handler->err_handler(skb, opt, type, code, offset, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 
 static const struct inet6_protocol tunnel6_protocol = {

net/ipv6/udp.c

@@ -517,7 +517,7 @@ static struct sock *__udp6_lib_err_encap(struct net *net,
 	return sk;
 }
 
-void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+int __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		   u8 type, u8 code, int offset, __be32 info,
 		   struct udp_table *udptable)
 {
@@ -544,7 +544,7 @@ void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		if (!sk) {
 			__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
 					  ICMP6_MIB_INERRORS);
-			return;
+			return -ENOENT;
 		}
 		tunnel = true;
 	}
@@ -583,7 +583,7 @@ void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	sk->sk_err = err;
 	sk->sk_error_report(sk);
 out:
-	return;
+	return 0;
 }
 
 static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
@@ -614,11 +614,11 @@ static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 	return 0;
 }
 
-static __inline__ void udpv6_err(struct sk_buff *skb,
+static __inline__ int udpv6_err(struct sk_buff *skb,
 				struct inet6_skb_parm *opt, u8 type,
 				u8 code, int offset, __be32 info)
 {
-	__udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
+	return __udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
 }
 
 static int udpv6_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)

net/ipv6/udp_impl.h

@@ -9,7 +9,7 @@
 #include <net/transp_v6.h>
 
 int __udp6_lib_rcv(struct sk_buff *, struct udp_table *, int);
-void __udp6_lib_err(struct sk_buff *, struct inet6_skb_parm *, u8, u8, int,
+int __udp6_lib_err(struct sk_buff *, struct inet6_skb_parm *, u8, u8, int,
 		   __be32, struct udp_table *);
 
 int udp_v6_get_port(struct sock *sk, unsigned short snum);

net/ipv6/udplite.c

@@ -20,11 +20,12 @@ static int udplitev6_rcv(struct sk_buff *skb)
 	return __udp6_lib_rcv(skb, &udplite_table, IPPROTO_UDPLITE);
 }
 
-static void udplitev6_err(struct sk_buff *skb,
+static int udplitev6_err(struct sk_buff *skb,
 			  struct inet6_skb_parm *opt,
 			  u8 type, u8 code, int offset, __be32 info)
 {
-	__udp6_lib_err(skb, opt, type, code, offset, info, &udplite_table);
+	return __udp6_lib_err(skb, opt, type, code, offset, info,
+			      &udplite_table);
 }
 
 static const struct inet6_protocol udplitev6_protocol = {

net/ipv6/xfrm6_protocol.c

@@ -80,14 +80,16 @@ static int xfrm6_esp_rcv(struct sk_buff *skb)
 	return 0;
 }
 
-static void xfrm6_esp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int xfrm6_esp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			  u8 type, u8 code, int offset, __be32 info)
 {
 	struct xfrm6_protocol *handler;
 
 	for_each_protocol_rcu(esp6_handlers, handler)
 		if (!handler->err_handler(skb, opt, type, code, offset, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 
 static int xfrm6_ah_rcv(struct sk_buff *skb)
@@ -107,14 +109,16 @@ static int xfrm6_ah_rcv(struct sk_buff *skb)
 	return 0;
 }
 
-static void xfrm6_ah_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int xfrm6_ah_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			 u8 type, u8 code, int offset, __be32 info)
 {
 	struct xfrm6_protocol *handler;
 
 	for_each_protocol_rcu(ah6_handlers, handler)
 		if (!handler->err_handler(skb, opt, type, code, offset, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 
 static int xfrm6_ipcomp_rcv(struct sk_buff *skb)
@@ -134,14 +138,16 @@ static int xfrm6_ipcomp_rcv(struct sk_buff *skb)
 	return 0;
 }
 
-static void xfrm6_ipcomp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int xfrm6_ipcomp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			     u8 type, u8 code, int offset, __be32 info)
 {
 	struct xfrm6_protocol *handler;
 
 	for_each_protocol_rcu(ipcomp6_handlers, handler)
 		if (!handler->err_handler(skb, opt, type, code, offset, info))
-			break;
+			return 0;
+
+	return -ENOENT;
 }
 
 static const struct inet6_protocol esp6_protocol = {

net/sctp/input.c

@@ -574,7 +574,7 @@ void sctp_err_finish(struct sock *sk, struct sctp_transport *t)
  * is probably better.
  *
  */
-void sctp_v4_err(struct sk_buff *skb, __u32 info)
+int sctp_v4_err(struct sk_buff *skb, __u32 info)
 {
 	const struct iphdr *iph = (const struct iphdr *)skb->data;
 	const int ihlen = iph->ihl * 4;
@@ -599,7 +599,7 @@ void sctp_v4_err(struct sk_buff *skb, __u32 info)
 	skb->transport_header = savesctp;
 	if (!sk) {
 		__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
-		return;
+		return -ENOENT;
 	}
 	/* Warning:  The sock lock is held.  Remember to call
 	 * sctp_err_finish!
@@ -653,6 +653,7 @@ void sctp_v4_err(struct sk_buff *skb, __u32 info)
 
 out_unlock:
 	sctp_err_finish(sk, transport);
+	return 0;
 }
 
 /*

net/sctp/ipv6.c

@@ -138,7 +138,7 @@ static struct notifier_block sctp_inet6addr_notifier = {
 };
 
 /* ICMP error handler. */
-static void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+static int sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			u8 type, u8 code, int offset, __be32 info)
 {
 	struct inet6_dev *idev;
@@ -147,7 +147,7 @@ static void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	struct sctp_transport *transport;
 	struct ipv6_pinfo *np;
 	__u16 saveip, savesctp;
-	int err;
+	int err, ret = 0;
 	struct net *net = dev_net(skb->dev);
 
 	idev = in6_dev_get(skb->dev);
@@ -163,6 +163,7 @@ static void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	skb->transport_header = savesctp;
 	if (!sk) {
 		__ICMP6_INC_STATS(net, idev, ICMP6_MIB_INERRORS);
+		ret = -ENOENT;
 		goto out;
 	}
 
@@ -202,6 +203,8 @@ static void sctp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 out:
 	if (likely(idev != NULL))
 		in6_dev_put(idev);
+
+	return ret;
 }
 
 static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport)