use MSG_TRUNC flag to get recv message size at once

prevent multiple calls of recvmsg.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>

diff --git a/lib/nl.c b/lib/nl.c
index 64e138260e8ee6b9f489f80d1b440d1d452f20f1..b572a1a3601c605bf2bae6f2b930ec590b6349c1 100644 (file)
--- a/lib/nl.c
+++ b/lib/nl.c
@@ -435,7 +435,7 @@ int nl_recv(struct nl_sock *sk, struct sockaddr_nl *nla,
        memset(nla, 0, sizeof(*nla));
 
        if (sk->s_flags & NL_MSG_PEEK)
-               flags |= MSG_PEEK;
+               flags |= MSG_PEEK | MSG_TRUNC;
 
        if (page_size == 0)
                page_size = getpagesize();
@@ -466,16 +466,17 @@ retry:
                }
        }
 
-       if (iov.iov_len < n ||
-           msg.msg_flags & MSG_TRUNC) {
+       if (msg.msg_flags & MSG_CTRUNC) {
+               msg.msg_controllen *= 2;
+               msg.msg_control = realloc(msg.msg_control, msg.msg_controllen);
+               goto retry;
+       } else if (iov.iov_len < n || msg.msg_flags & MSG_TRUNC) {
                /* Provided buffer is not long enough, enlarge it
+                * to size of n (which should be total length of the message)
                 * and try again. */
-               iov.iov_len *= 2;
+               iov.iov_len = n;
                iov.iov_base = *buf = realloc(*buf, iov.iov_len);
-               goto retry;
-       } else if (msg.msg_flags & MSG_CTRUNC) {
-               msg.msg_controllen *= 2;
-               msg.msg_control = realloc(msg.msg_control, msg.msg_controllen);
+               flags = 0;
                goto retry;
        } else if (flags != 0) {
                /* Buffer is big enough, do the actual reading */