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>

5 files changed, 11 insertions, 6 deletions

diff --git a/include/net/icmp.h b/include/net/icmp.h
index 3ef2743a8eec..6ac3a5bd0117 100644
--- a/include/net/icmp.h
+++ b/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);
 
diff --git a/include/net/protocol.h b/include/net/protocol.h
index 4fc75f7ae23b..92b3eaad6088 100644
--- a/include/net/protocol.h
+++ b/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 */
 };
 
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 8c2caa370e0f..9a3b48a35e90 100644
--- a/include/net/sctp/sctp.h
+++ b/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 *,
diff --git a/include/net/tcp.h b/include/net/tcp.h
index a18914d20486..4743836bed2e 100644
--- a/include/net/tcp.h
+++ b/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);
 
diff --git a/include/net/udp.h b/include/net/udp.h
index eccca2325ee6..fd6d948755c8 100644
--- a/include/net/udp.h
+++ b/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);