linux/net/ipv6/tunnel6.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

198 lines
4.9 KiB
C

/*
* Copyright (C)2003,2004 USAGI/WIDE Project
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
* Authors Mitsuru KANDA <mk@linux-ipv6.org>
* YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
*/
#define pr_fmt(fmt) "IPv6: " fmt
#include <linux/icmpv6.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/xfrm.h>
static struct xfrm6_tunnel __rcu *tunnel6_handlers __read_mostly;
static struct xfrm6_tunnel __rcu *tunnel46_handlers __read_mostly;
static DEFINE_MUTEX(tunnel6_mutex);
int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family)
{
struct xfrm6_tunnel __rcu **pprev;
struct xfrm6_tunnel *t;
int ret = -EEXIST;
int priority = handler->priority;
mutex_lock(&tunnel6_mutex);
for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
(t = rcu_dereference_protected(*pprev,
lockdep_is_held(&tunnel6_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(&tunnel6_mutex);
return ret;
}
EXPORT_SYMBOL(xfrm6_tunnel_register);
int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family)
{
struct xfrm6_tunnel __rcu **pprev;
struct xfrm6_tunnel *t;
int ret = -ENOENT;
mutex_lock(&tunnel6_mutex);
for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
(t = rcu_dereference_protected(*pprev,
lockdep_is_held(&tunnel6_mutex))) != NULL;
pprev = &t->next) {
if (t == handler) {
*pprev = handler->next;
ret = 0;
break;
}
}
mutex_unlock(&tunnel6_mutex);
synchronize_net();
return ret;
}
EXPORT_SYMBOL(xfrm6_tunnel_deregister);
#define for_each_tunnel_rcu(head, handler) \
for (handler = rcu_dereference(head); \
handler != NULL; \
handler = rcu_dereference(handler->next)) \
static int tunnel6_rcv(struct sk_buff *skb)
{
struct xfrm6_tunnel *handler;
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
goto drop;
for_each_tunnel_rcu(tunnel6_handlers, handler)
if (!handler->handler(skb))
return 0;
icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
drop:
kfree_skb(skb);
return 0;
}
static int tunnel46_rcv(struct sk_buff *skb)
{
struct xfrm6_tunnel *handler;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto drop;
for_each_tunnel_rcu(tunnel46_handlers, handler)
if (!handler->handler(skb))
return 0;
icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
drop:
kfree_skb(skb);
return 0;
}
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))
return 0;
return -ENOENT;
}
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))
return 0;
return -ENOENT;
}
static const struct inet6_protocol tunnel6_protocol = {
.handler = tunnel6_rcv,
.err_handler = tunnel6_err,
.flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
};
static const struct inet6_protocol tunnel46_protocol = {
.handler = tunnel46_rcv,
.err_handler = tunnel46_err,
.flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
};
static int __init tunnel6_init(void)
{
if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
pr_err("%s: can't add protocol\n", __func__);
return -EAGAIN;
}
if (inet6_add_protocol(&tunnel46_protocol, IPPROTO_IPIP)) {
pr_err("%s: can't add protocol\n", __func__);
inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
return -EAGAIN;
}
return 0;
}
static void __exit tunnel6_fini(void)
{
if (inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP))
pr_err("%s: can't remove protocol\n", __func__);
if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
pr_err("%s: can't remove protocol\n", __func__);
}
module_init(tunnel6_init);
module_exit(tunnel6_fini);
MODULE_LICENSE("GPL");