ip: use rtnl_send_check() on flush commands, closes 6962

function                                             old     new   delta
rtnl_send_check                                        -     160    +160
xrtnl_wilddump_request                                64      66      +2
ipneigh_list_or_flush                                714     706      -8
rtnl_send                                             69       -     -69
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 1/1 up/down: 162/-77)            Total: 85 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/libiproute/libnetlink.h b/networking/libiproute/libnetlink.h
index 51bee2d..1b082e0 100644
--- a/networking/libiproute/libnetlink.h
+++ b/networking/libiproute/libnetlink.h
@@ -20,7 +20,7 @@
 
 extern void xrtnl_open(struct rtnl_handle *rth) FAST_FUNC;
 #define rtnl_close(rth) (close((rth)->fd))
-extern int xrtnl_wilddump_request(struct rtnl_handle *rth, int fam, int type) FAST_FUNC;
+extern void xrtnl_wilddump_request(struct rtnl_handle *rth, int fam, int type) FAST_FUNC;
 extern int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len) FAST_FUNC;
 extern int xrtnl_dump_filter(struct rtnl_handle *rth,
 		int (*filter)(const struct sockaddr_nl*, struct nlmsghdr *n, void*) FAST_FUNC,
@@ -34,8 +34,23 @@
 		int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 		void *jarg) FAST_FUNC;
 
-extern int rtnl_send(struct rtnl_handle *rth, char *buf, int) FAST_FUNC;
+int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len) FAST_FUNC;
+//TODO: pass rth->fd instead of full rth?
+static ALWAYS_INLINE void rtnl_send(struct rtnl_handle *rth, const void *buf, int len)
+{
+	// Used to be:
+	//struct sockaddr_nl nladdr;
+	//memset(&nladdr, 0, sizeof(nladdr));
+	//nladdr.nl_family = AF_NETLINK;
+	//return xsendto(rth->fd, buf, len, (struct sockaddr*)&nladdr, sizeof(nladdr));
 
+	// iproute2-4.2.0 simplified the above to:
+	//return send(rth->fd, buf, len, 0);
+
+	// We are using even shorter:
+	xwrite(rth->fd, buf, len);
+	// and convert to void, inline.
+}
 
 extern int addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t data) FAST_FUNC;
 extern int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen) FAST_FUNC;