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>

8 files changed, 55 insertions, 37 deletions

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index c9c53ade55c3..5d7aa2c2770c 100644
--- a/net/ipv6/icmp.c
+++ b/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);
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 515adbdba1d2..81b69bcee714 100644
--- a/net/ipv6/ip6_gre.c
+++ b/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)
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 03e6b7a2bc53..a3f559162521 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/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;
 }
 
 
diff --git a/net/ipv6/tunnel6.c b/net/ipv6/tunnel6.c
index dae25cad05cd..1991dede7367 100644
--- a/net/ipv6/tunnel6.c
+++ b/net/ipv6/tunnel6.c
@@ -134,24 +134,28 @@ drop:
 	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 = {
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1216c920f945..61316ec48b51 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -517,9 +517,9 @@ 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,
-		    u8 type, u8 code, int offset, __be32 info,
-		    struct udp_table *udptable)
+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)
 {
 	struct ipv6_pinfo *np;
 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
@@ -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,
-				 struct inet6_skb_parm *opt, u8 type,
-				 u8 code, int offset, __be32 info)
+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)
diff --git a/net/ipv6/udp_impl.h b/net/ipv6/udp_impl.h
index 7903e21c178b..5730e6503cb4 100644
--- a/net/ipv6/udp_impl.h
+++ b/net/ipv6/udp_impl.h
@@ -9,8 +9,8 @@
 #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,
-		    __be32, struct udp_table *);
+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);
 
diff --git a/net/ipv6/udplite.c b/net/ipv6/udplite.c
index 5000ad6878e6..a125aebc29e5 100644
--- a/net/ipv6/udplite.c
+++ b/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 = {
diff --git a/net/ipv6/xfrm6_protocol.c b/net/ipv6/xfrm6_protocol.c
index b2dc8ce49378..cc979b702c89 100644
--- a/net/ipv6/xfrm6_protocol.c
+++ b/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 = {