[NETLINK]: New message building macros
NLMSG_PUT_ANSWER(skb, nlcb, type, length)
Start a new netlink message as answer to a request,
returns the message header.
NLMSG_END(skb, nlh)
End a netlink message, fixes total message length,
returns skb->len.
NLMSG_CANCEL(skb, nlh)
Cancel the building process and trim whole message
from skb again, returns -1.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index b2738ac..8d1cb41 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -171,8 +171,21 @@
}
#define NLMSG_PUT(skb, pid, seq, type, len) \
-({ if (skb_tailroom(skb) < (int)NLMSG_SPACE(len)) goto nlmsg_failure; \
- __nlmsg_put(skb, pid, seq, type, len); })
+({ if (skb_tailroom(skb) < (int)NLMSG_SPACE(len)) \
+ goto nlmsg_failure; \
+ __nlmsg_put(skb, pid, seq, type, len); })
+
+#define NLMSG_PUT_ANSWER(skb, cb, type, len) \
+ NLMSG_PUT(skb, NETLINK_CB((cb)->skb).pid, \
+ (cb)->nlh->nlmsg_seq, type, len)
+
+#define NLMSG_END(skb, nlh) \
+({ (nlh)->nlmsg_len = (skb)->tail - (unsigned char *) (nlh); \
+ (skb)->len; })
+
+#define NLMSG_CANCEL(skb, nlh) \
+({ skb_trim(skb, (unsigned char *) (nlh) - (skb)->data); \
+ -1; })
extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
struct nlmsghdr *nlh,