Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e284986385b6420a5f30f2dcd743512bbe1a3202
Commit:     e284986385b6420a5f30f2dcd743512bbe1a3202
Parent:     30833ffead66e1f0052150a51db0b45151189ac1
Author:     Thomas Graf <[EMAIL PROTECTED]>
AuthorDate: Thu Mar 22 11:48:11 2007 -0700
Committer:  David S. Miller <[EMAIL PROTECTED]>
CommitDate: Wed Apr 25 22:27:04 2007 -0700

    [RTNL]: Message handler registration interface
    
    This patch adds a new interface to register rtnetlink message
    handlers replacing the exported rtnl_links[] array which
    required many message handlers to be exported unnecessarly.
    
    Signed-off-by: Thomas Graf <[EMAIL PROTECTED]>
    Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
---
 include/linux/rtnetlink.h |    7 --
 include/net/rtnetlink.h   |   18 +++++
 net/core/rtnetlink.c      |  188 +++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 184 insertions(+), 29 deletions(-)

diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index 3a4cb24..1fae30a 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -574,13 +574,6 @@ extern int rtattr_parse(struct rtattr *tb[], int maxattr, 
struct rtattr *rta, in
 #define rtattr_parse_nested(tb, max, rta) \
        rtattr_parse((tb), (max), RTA_DATA((rta)), RTA_PAYLOAD((rta)))
 
-struct rtnetlink_link
-{
-       int (*doit)(struct sk_buff *, struct nlmsghdr*, void *attr);
-       int (*dumpit)(struct sk_buff *, struct netlink_callback *cb);
-};
-
-extern struct rtnetlink_link * rtnetlink_links[NPROTO];
 extern int rtnetlink_send(struct sk_buff *skb, u32 pid, u32 group, int echo);
 extern int rtnl_unicast(struct sk_buff *skb, u32 pid);
 extern int rtnl_notify(struct sk_buff *skb, u32 pid, u32 group,
diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
new file mode 100644
index 0000000..dce7072
--- /dev/null
+++ b/include/net/rtnetlink.h
@@ -0,0 +1,18 @@
+#ifndef __NET_RTNETLINK_H
+#define __NET_RTNETLINK_H
+
+#include <linux/rtnetlink.h>
+#include <net/netlink.h>
+
+typedef int (*rtnl_doit_func)(struct sk_buff *, struct nlmsghdr *, void *);
+typedef int (*rtnl_dumpit_func)(struct sk_buff *, struct netlink_callback *);
+
+extern int     __rtnl_register(int protocol, int msgtype,
+                               rtnl_doit_func, rtnl_dumpit_func);
+extern void    rtnl_register(int protocol, int msgtype,
+                             rtnl_doit_func, rtnl_dumpit_func);
+extern int     rtnl_unregister(int protocol, int msgtype);
+extern void    rtnl_unregister_all(int protocol);
+extern int     rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb);
+
+#endif
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 33ea8ea..fb1630d 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -50,12 +50,18 @@
 #include <net/sock.h>
 #include <net/pkt_sched.h>
 #include <net/fib_rules.h>
-#include <net/netlink.h>
+#include <net/rtnetlink.h>
 #ifdef CONFIG_NET_WIRELESS_RTNETLINK
 #include <linux/wireless.h>
 #include <net/iw_handler.h>
 #endif /* CONFIG_NET_WIRELESS_RTNETLINK */
 
+struct rtnl_link
+{
+       rtnl_doit_func          doit;
+       rtnl_dumpit_func        dumpit;
+};
+
 static DEFINE_MUTEX(rtnl_mutex);
 static struct sock *rtnl;
 
@@ -95,7 +101,151 @@ int rtattr_parse(struct rtattr *tb[], int maxattr, struct 
rtattr *rta, int len)
        return 0;
 }
 
-struct rtnetlink_link * rtnetlink_links[NPROTO];
+struct rtnl_link *rtnl_msg_handlers[NPROTO];
+
+static inline int rtm_msgindex(int msgtype)
+{
+       int msgindex = msgtype - RTM_BASE;
+
+       /*
+        * msgindex < 0 implies someone tried to register a netlink
+        * control code. msgindex >= RTM_NR_MSGTYPES may indicate that
+        * the message type has not been added to linux/rtnetlink.h
+        */
+       BUG_ON(msgindex < 0 || msgindex >= RTM_NR_MSGTYPES);
+
+       return msgindex;
+}
+
+static rtnl_doit_func rtnl_get_doit(int protocol, int msgindex)
+{
+       struct rtnl_link *tab;
+
+       tab = rtnl_msg_handlers[protocol];
+       if (tab == NULL || tab->doit == NULL)
+               tab = rtnl_msg_handlers[PF_UNSPEC];
+
+       return tab ? tab->doit : NULL;
+}
+
+static rtnl_dumpit_func rtnl_get_dumpit(int protocol, int msgindex)
+{
+       struct rtnl_link *tab;
+
+       tab = rtnl_msg_handlers[protocol];
+       if (tab == NULL || tab->dumpit == NULL)
+               tab = rtnl_msg_handlers[PF_UNSPEC];
+
+       return tab ? tab->dumpit : NULL;
+}
+
+/**
+ * __rtnl_register - Register a rtnetlink message type
+ * @protocol: Protocol family or PF_UNSPEC
+ * @msgtype: rtnetlink message type
+ * @doit: Function pointer called for each request message
+ * @dumpit: Function pointer called for each dump request (NLM_F_DUMP) message
+ *
+ * Registers the specified function pointers (at least one of them has
+ * to be non-NULL) to be called whenever a request message for the
+ * specified protocol family and message type is received.
+ *
+ * The special protocol family PF_UNSPEC may be used to define fallback
+ * function pointers for the case when no entry for the specific protocol
+ * family exists.
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int __rtnl_register(int protocol, int msgtype,
+                   rtnl_doit_func doit, rtnl_dumpit_func dumpit)
+{
+       struct rtnl_link *tab;
+       int msgindex;
+
+       BUG_ON(protocol < 0 || protocol >= NPROTO);
+       msgindex = rtm_msgindex(msgtype);
+
+       tab = rtnl_msg_handlers[protocol];
+       if (tab == NULL) {
+               tab = kcalloc(RTM_NR_MSGTYPES, sizeof(*tab), GFP_KERNEL);
+               if (tab == NULL)
+                       return -ENOBUFS;
+
+               rtnl_msg_handlers[protocol] = tab;
+       }
+
+       if (doit)
+               tab[msgindex].doit = doit;
+
+       if (dumpit)
+               tab[msgindex].dumpit = dumpit;
+
+       return 0;
+}
+
+EXPORT_SYMBOL_GPL(__rtnl_register);
+
+/**
+ * rtnl_register - Register a rtnetlink message type
+ *
+ * Identical to __rtnl_register() but panics on failure. This is useful
+ * as failure of this function is very unlikely, it can only happen due
+ * to lack of memory when allocating the chain to store all message
+ * handlers for a protocol. Meant for use in init functions where lack
+ * of memory implies no sense in continueing.
+ */
+void rtnl_register(int protocol, int msgtype,
+                  rtnl_doit_func doit, rtnl_dumpit_func dumpit)
+{
+       if (__rtnl_register(protocol, msgtype, doit, dumpit) < 0)
+               panic("Unable to register rtnetlink message handler, "
+                     "protocol = %d, message type = %d\n",
+                     protocol, msgtype);
+}
+
+EXPORT_SYMBOL_GPL(rtnl_register);
+
+/**
+ * rtnl_unregister - Unregister a rtnetlink message type
+ * @protocol: Protocol family or PF_UNSPEC
+ * @msgtype: rtnetlink message type
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int rtnl_unregister(int protocol, int msgtype)
+{
+       int msgindex;
+
+       BUG_ON(protocol < 0 || protocol >= NPROTO);
+       msgindex = rtm_msgindex(msgtype);
+
+       if (rtnl_msg_handlers[protocol] == NULL)
+               return -ENOENT;
+
+       rtnl_msg_handlers[protocol][msgindex].doit = NULL;
+       rtnl_msg_handlers[protocol][msgindex].dumpit = NULL;
+
+       return 0;
+}
+
+EXPORT_SYMBOL_GPL(rtnl_unregister);
+
+/**
+ * rtnl_unregister_all - Unregister all rtnetlink message type of a protocol
+ * @protocol : Protocol family or PF_UNSPEC
+ *
+ * Identical to calling rtnl_unregster() for all registered message types
+ * of a certain protocol family.
+ */
+void rtnl_unregister_all(int protocol)
+{
+       BUG_ON(protocol < 0 || protocol >= NPROTO);
+
+       kfree(rtnl_msg_handlers[protocol]);
+       rtnl_msg_handlers[protocol] = NULL;
+}
+
+EXPORT_SYMBOL_GPL(rtnl_unregister_all);
 
 static const int rtm_min[RTM_NR_FAMILIES] =
 {
@@ -648,7 +798,7 @@ errout:
        return err;
 }
 
-static int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb)
+int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb)
 {
        int idx;
        int s_idx = cb->family;
@@ -659,12 +809,12 @@ static int rtnl_dump_all(struct sk_buff *skb, struct 
netlink_callback *cb)
                int type = cb->nlh->nlmsg_type-RTM_BASE;
                if (idx < s_idx || idx == PF_PACKET)
                        continue;
-               if (rtnetlink_links[idx] == NULL ||
-                   rtnetlink_links[idx][type].dumpit == NULL)
+               if (rtnl_msg_handlers[idx] == NULL ||
+                   rtnl_msg_handlers[idx][type].dumpit == NULL)
                        continue;
                if (idx > s_idx)
                        memset(&cb->args[0], 0, sizeof(cb->args));
-               if (rtnetlink_links[idx][type].dumpit(skb, cb))
+               if (rtnl_msg_handlers[idx][type].dumpit(skb, cb))
                        break;
        }
        cb->family = idx;
@@ -672,6 +822,8 @@ static int rtnl_dump_all(struct sk_buff *skb, struct 
netlink_callback *cb)
        return skb->len;
 }
 
+EXPORT_SYMBOL_GPL(rtnl_dump_all);
+
 void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change)
 {
        struct sk_buff *skb;
@@ -703,8 +855,7 @@ static int rtattr_max;
 static __inline__ int
 rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, int *errp)
 {
-       struct rtnetlink_link *link;
-       struct rtnetlink_link *link_tab;
+       rtnl_doit_func doit;
        int sz_idx, kind;
        int min_len;
        int family;
@@ -737,11 +888,6 @@ rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr 
*nlh, int *errp)
                return -1;
        }
 
-       link_tab = rtnetlink_links[family];
-       if (link_tab == NULL)
-               link_tab = rtnetlink_links[PF_UNSPEC];
-       link = &link_tab[type];
-
        sz_idx = type>>2;
        kind = type&3;
 
@@ -751,14 +897,14 @@ rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr 
*nlh, int *errp)
        }
 
        if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {
-               if (link->dumpit == NULL)
-                       link = &(rtnetlink_links[PF_UNSPEC][type]);
+               rtnl_dumpit_func dumpit;
 
-               if (link->dumpit == NULL)
+               dumpit = rtnl_get_dumpit(family, type);
+               if (dumpit == NULL)
                        goto err_inval;
 
                if ((*errp = netlink_dump_start(rtnl, skb, nlh,
-                                               link->dumpit, NULL)) != 0) {
+                                               dumpit, NULL)) != 0) {
                        return -1;
                }
 
@@ -787,11 +933,10 @@ rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr 
*nlh, int *errp)
                }
        }
 
-       if (link->doit == NULL)
-               link = &(rtnetlink_links[PF_UNSPEC][type]);
-       if (link->doit == NULL)
+       doit = rtnl_get_doit(family, type);
+       if (doit == NULL)
                goto err_inval;
-       err = link->doit(skb, nlh, (void *)&rta_buf[0]);
+       err = doit(skb, nlh, (void *)&rta_buf[0]);
 
        *errp = err;
        return err;
@@ -886,7 +1031,6 @@ void __init rtnetlink_init(void)
 EXPORT_SYMBOL(__rta_fill);
 EXPORT_SYMBOL(rtattr_strlcpy);
 EXPORT_SYMBOL(rtattr_parse);
-EXPORT_SYMBOL(rtnetlink_links);
 EXPORT_SYMBOL(rtnetlink_put_metrics);
 EXPORT_SYMBOL(rtnl_lock);
 EXPORT_SYMBOL(rtnl_trylock);
-
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