linux/net/ipv4/tunnel4.c
Stefano Brivio 32bbd8793f 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>
2018-11-08 17:13:08 -08:00

257 lines
5.5 KiB
C

/* tunnel4.c: Generic IP tunnel transformer.
*
* Copyright (C) 2003 David S. Miller (davem@redhat.com)
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/mpls.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/xfrm.h>
static struct xfrm_tunnel __rcu *tunnel4_handlers __read_mostly;
static struct xfrm_tunnel __rcu *tunnel64_handlers __read_mostly;
static struct xfrm_tunnel __rcu *tunnelmpls4_handlers __read_mostly;
static DEFINE_MUTEX(tunnel4_mutex);
static inline struct xfrm_tunnel __rcu **fam_handlers(unsigned short family)
{
return (family == AF_INET) ? &tunnel4_handlers :
(family == AF_INET6) ? &tunnel64_handlers :
&tunnelmpls4_handlers;
}
int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
{
struct xfrm_tunnel __rcu **pprev;
struct xfrm_tunnel *t;
int ret = -EEXIST;
int priority = handler->priority;
mutex_lock(&tunnel4_mutex);
for (pprev = fam_handlers(family);
(t = rcu_dereference_protected(*pprev,
lockdep_is_held(&tunnel4_mutex))) != NULL;
pprev = &t->next) {
if (t->priority > priority)
break;
if (t->priority == priority)
goto err;
}
handler->next = *pprev;
rcu_assign_pointer(*pprev, handler);
ret = 0;
err:
mutex_unlock(&tunnel4_mutex);
return ret;
}
EXPORT_SYMBOL(xfrm4_tunnel_register);
int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family)
{
struct xfrm_tunnel __rcu **pprev;
struct xfrm_tunnel *t;
int ret = -ENOENT;
mutex_lock(&tunnel4_mutex);
for (pprev = fam_handlers(family);
(t = rcu_dereference_protected(*pprev,
lockdep_is_held(&tunnel4_mutex))) != NULL;
pprev = &t->next) {
if (t == handler) {
*pprev = handler->next;
ret = 0;
break;
}
}
mutex_unlock(&tunnel4_mutex);
synchronize_net();
return ret;
}
EXPORT_SYMBOL(xfrm4_tunnel_deregister);
#define for_each_tunnel_rcu(head, handler) \
for (handler = rcu_dereference(head); \
handler != NULL; \
handler = rcu_dereference(handler->next)) \
static int tunnel4_rcv(struct sk_buff *skb)
{
struct xfrm_tunnel *handler;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto drop;
for_each_tunnel_rcu(tunnel4_handlers, handler)
if (!handler->handler(skb))
return 0;
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
drop:
kfree_skb(skb);
return 0;
}
#if IS_ENABLED(CONFIG_IPV6)
static int tunnel64_rcv(struct sk_buff *skb)
{
struct xfrm_tunnel *handler;
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
goto drop;
for_each_tunnel_rcu(tunnel64_handlers, handler)
if (!handler->handler(skb))
return 0;
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
drop:
kfree_skb(skb);
return 0;
}
#endif
#if IS_ENABLED(CONFIG_MPLS)
static int tunnelmpls4_rcv(struct sk_buff *skb)
{
struct xfrm_tunnel *handler;
if (!pskb_may_pull(skb, sizeof(struct mpls_label)))
goto drop;
for_each_tunnel_rcu(tunnelmpls4_handlers, handler)
if (!handler->handler(skb))
return 0;
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
drop:
kfree_skb(skb);
return 0;
}
#endif
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))
return 0;
return -ENOENT;
}
#if IS_ENABLED(CONFIG_IPV6)
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))
return 0;
return -ENOENT;
}
#endif
#if IS_ENABLED(CONFIG_MPLS)
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))
return 0;
return -ENOENT;
}
#endif
static const struct net_protocol tunnel4_protocol = {
.handler = tunnel4_rcv,
.err_handler = tunnel4_err,
.no_policy = 1,
.netns_ok = 1,
};
#if IS_ENABLED(CONFIG_IPV6)
static const struct net_protocol tunnel64_protocol = {
.handler = tunnel64_rcv,
.err_handler = tunnel64_err,
.no_policy = 1,
.netns_ok = 1,
};
#endif
#if IS_ENABLED(CONFIG_MPLS)
static const struct net_protocol tunnelmpls4_protocol = {
.handler = tunnelmpls4_rcv,
.err_handler = tunnelmpls4_err,
.no_policy = 1,
.netns_ok = 1,
};
#endif
static int __init tunnel4_init(void)
{
if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP))
goto err;
#if IS_ENABLED(CONFIG_IPV6)
if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
goto err;
}
#endif
#if IS_ENABLED(CONFIG_MPLS)
if (inet_add_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS)) {
inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
#if IS_ENABLED(CONFIG_IPV6)
inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6);
#endif
goto err;
}
#endif
return 0;
err:
pr_err("%s: can't add protocol\n", __func__);
return -EAGAIN;
}
static void __exit tunnel4_fini(void)
{
#if IS_ENABLED(CONFIG_MPLS)
if (inet_del_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS))
pr_err("tunnelmpls4 close: can't remove protocol\n");
#endif
#if IS_ENABLED(CONFIG_IPV6)
if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
pr_err("tunnel64 close: can't remove protocol\n");
#endif
if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
pr_err("tunnel4 close: can't remove protocol\n");
}
module_init(tunnel4_init);
module_exit(tunnel4_fini);
MODULE_LICENSE("GPL");