[PATCH RFC net-next] ipv6: Kill ipv6 dependency of icmpv6_send().

Pravin B Shelar
2013-04-23T23:49:21Z

Following patch adds icmp-registration module for ipv6. It allows
ipv6 protocol to register icmp_sender which is used for sending
ipv6 icmp msgs. This extra layer allows us to kill dependency
on ipv6 for icmpv6_send() function.

This patch also fixes ip_tunnel compilation problem when ip_tunnel
is statically compiled in kernel but ipv6 is module.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
---
include/linux/icmpv6.h | 18 +++++++++++--
net/ipv6/Makefile | 2 +-
net/ipv6/icmp.c | 35 +++++++++++++++-----------
net/ipv6/ip6_icmp.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 100 insertions(+), 19 deletions(-)
create mode 100644 net/ipv6/ip6_icmp.c

diff --git a/include/linux/icmpv6.h b/include/linux/icmpv6.h
index b4f6c29..630f453 100644
--- a/include/linux/icmpv6.h
+++ b/include/linux/icmpv6.h
@@ -11,9 +11,21 @@ static inline struct icmp6hdr *icmp6_hdr(const struct sk_buff *skb)

#include <linux/netdevice.h>

-extern void icmpv6_send(struct sk_buff *skb,
- u8 type, u8 code,
- __u32 info);
+#if IS_ENABLED(CONFIG_IPV6)
+extern void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info);
+
+typedef void ip6_icmp_send_t(struct sk_buff *skb, u8 type, u8 code, __u32 info);
+extern int inet6_register_icmp_sender(ip6_icmp_send_t *fn);
+extern int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn);
+
+#else
+
+static inline void icmpv6_send(struct sk_buff *skb,
+ u8 type, u8 code, __u32 info)
+{
+
+}
+#endif

extern int icmpv6_init(void);
extern int icmpv6_err_convert(u8 type, u8 code,
diff --git a/net/ipv6/Makefile b/net/ipv6/Makefile
index 309af19..9af088d 100644
--- a/net/ipv6/Makefile
+++ b/net/ipv6/Makefile
@@ -40,7 +40,7 @@ obj-$(CONFIG_IPV6_SIT) += sit.o
obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o
obj-$(CONFIG_IPV6_GRE) += ip6_gre.o

-obj-y += addrconf_core.o exthdrs_core.o ip6_checksum.o
+obj-y += addrconf_core.o exthdrs_core.o ip6_checksum.o ip6_icmp.o
obj-$(CONFIG_INET) += output_core.o protocol.o $(ipv6-offload)

obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 71b900c..2a53a79 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -124,15 +124,6 @@ static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
}

/*
- * Slightly more convenient version of icmpv6_send.
- */
-void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
-{
- icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
- kfree_skb(skb);
-}
-
-/*
* Figure out, may we reply to this packet with icmp error.
*
* We do not reply, if:
@@ -332,7 +323,7 @@ static struct dst_entry *icmpv6_route_lookup(struct net *net, struct sk_buff *sk
* anycast.
*/
if (((struct rt6_info *)dst)->rt6i_flags & RTF_ANYCAST) {
- LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: acast source\n");
+ LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: acast source\n");
dst_release(dst);
return ERR_PTR(-EINVAL);
}
@@ -381,7 +372,7 @@ relookup_failed:
/*
* Send an ICMP message in response to a packet in error
*/
-void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
+static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
{
struct net *net = dev_net(skb->dev);
struct inet6_dev *idev = NULL;
@@ -406,7 +397,7 @@ void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
/*
* Make sure we respect the rules
* i.e. RFC 1885 2.4(e)
- * Rule (e.1) is enforced by not using icmpv6_send
+ * Rule (e.1) is enforced by not using icmp6_send
* in any code that processes icmp errors.
*/
addr_type = ipv6_addr_type(&hdr->daddr);
@@ -444,7 +435,7 @@ void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
* and anycast addresses will be checked later.
*/
if ((addr_type == IPV6_ADDR_ANY) || (addr_type & IPV6_ADDR_MULTICAST)) {
- LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: addr_any/mcast source\n");
+ LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: addr_any/mcast source\n");
return;
}

@@ -452,7 +443,7 @@ void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
* Never answer to a ICMP packet.
*/
if (is_ineligible(skb)) {
- LIMIT_NETDEBUG(KERN_DEBUG "icmpv6_send: no reply to icmp error\n");
+ LIMIT_NETDEBUG(KERN_DEBUG "icmp6_send: no reply to icmp error\n");
return;
}

@@ -529,7 +520,14 @@ out_dst_release:
out:
icmpv6_xmit_unlock(sk);
}
-EXPORT_SYMBOL(icmpv6_send);
+
+/* Slightly more convenient version of icmp6_send.
+ */
+void icmpv6_param_prob(struct sk_buff *skb, u8 code, int pos)
+{
+ icmp6_send(skb, ICMPV6_PARAMPROB, code, pos);
+ kfree_skb(skb);
+}

static void icmpv6_echo_reply(struct sk_buff *skb)
{
@@ -885,8 +883,14 @@ int __init icmpv6_init(void)
err = -EAGAIN;
if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
goto fail;
+
+ err = inet6_register_icmp_sender(icmp6_send);
+ if (err)
+ goto sender_reg_err;
return 0;

+sender_reg_err:
+ inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
fail:
pr_err("Failed to register ICMP6 protocol\n");
unregister_pernet_subsys(&icmpv6_sk_ops);
@@ -895,6 +899,7 @@ fail:

void icmpv6_cleanup(void)
{
+ inet6_unregister_icmp_sender(icmp6_send);
unregister_pernet_subsys(&icmpv6_sk_ops);
inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
}
diff --git a/net/ipv6/ip6_icmp.c b/net/ipv6/ip6_icmp.c
new file mode 100644
index 0000000..cfcc563
--- /dev/null
+++ b/net/ipv6/ip6_icmp.c
@@ -0,0 +1,64 @@
+#include <linux/export.h>
+#include <linux/icmpv6.h>
+#include <linux/mutex.h>
+#include <linux/netdevice.h>
+#include <linux/spinlock.h>
+
+#include <net/ipv6.h>
+
+#if IS_ENABLED(CONFIG_IPV6)
+
+static ip6_icmp_send_t __rcu *ip6_icmp_send;
+static DEFINE_MUTEX(handler_lock);
+
+int inet6_register_icmp_sender(ip6_icmp_send_t *fn)
+{
+ int ret = 0;
+
+ mutex_lock(&handler_lock);
+ if (rcu_dereference(ip6_icmp_send)) {
+ ret = -EBUSY;
+ goto out;
+ }
+ rcu_assign_pointer(ip6_icmp_send, fn);
+
+out:
+ mutex_unlock(&handler_lock);
+ return ret;
+}
+EXPORT_SYMBOL(inet6_register_icmp_sender);
+
+int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn)
+{
+ int ret = 0;
+
+ mutex_lock(&handler_lock);
+ if (rcu_dereference(ip6_icmp_send) != fn) {
+ ret = -EINVAL;
+ goto out;
+ }
+ rcu_assign_pointer(ip6_icmp_send, NULL);
+
+out:
+ mutex_unlock(&handler_lock);
+ synchronize_net();
+
+ return ret;
+}
+EXPORT_SYMBOL(inet6_unregister_icmp_sender);
+
+void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
+{
+ ip6_icmp_send_t *send;
+
+ rcu_read_lock();
+ send = rcu_dereference(ip6_icmp_send);
+
+ if (!send)
+ goto out;
+ send(skb, type, code, info);
+out:
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL(icmpv6_send);
+#endif
--
1.7.1