inet_diag: Export inet diag cookie checking routine

The netlink diag susbsys stores sk address bits in the nl message
as a "cookie" and uses one when dumps details about particular
socket.

The same will be required for udp diag module, so introduce a heler
in inet_diag module

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/inet_diag.h b/include/linux/inet_diag.h
index 851feff..5036747 100644 (file)
--- a/include/linux/inet_diag.h
+++ b/include/linux/inet_diag.h
@@ -144,6 +144,8 @@ struct inet_diag_handler {
        __u16                   idiag_type;
 };
 
+int inet_diag_check_cookie(struct sock *sk, struct inet_diag_req *req);
+
 extern int  inet_diag_register(const struct inet_diag_handler *handler);
 extern void inet_diag_unregister(const struct inet_diag_handler *handler);
 #endif /* __KERNEL__ */

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index bd3f661..ba3ae1f 100644 (file)
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -246,6 +246,18 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
        return inet_csk_diag_fill(sk, skb, r, pid, seq, nlmsg_flags, unlh);
 }
 
+int inet_diag_check_cookie(struct sock *sk, struct inet_diag_req *req)
+{
+       if ((req->id.idiag_cookie[0] != INET_DIAG_NOCOOKIE ||
+            req->id.idiag_cookie[1] != INET_DIAG_NOCOOKIE) &&
+           ((u32)(unsigned long)sk != req->id.idiag_cookie[0] ||
+            (u32)((((unsigned long)sk) >> 31) >> 1) != req->id.idiag_cookie[1]))
+               return -ESTALE;
+       else
+               return 0;
+}
+EXPORT_SYMBOL_GPL(inet_diag_check_cookie);
+
 static int inet_diag_get_exact(struct sk_buff *in_skb,
                               const struct nlmsghdr *nlh,
                               struct inet_diag_req *req)
@@ -288,11 +300,8 @@ static int inet_diag_get_exact(struct sk_buff *in_skb,
        if (sk == NULL)
                goto unlock;
 
-       err = -ESTALE;
-       if ((req->id.idiag_cookie[0] != INET_DIAG_NOCOOKIE ||
-            req->id.idiag_cookie[1] != INET_DIAG_NOCOOKIE) &&
-           ((u32)(unsigned long)sk != req->id.idiag_cookie[0] ||
-            (u32)((((unsigned long)sk) >> 31) >> 1) != req->id.idiag_cookie[1]))
+       err = inet_diag_check_cookie(sk, req);
+       if (err)
                goto out;
 
        err = -ENOMEM;