lib/socket: add nl_socket_set_fd() function

This is based on the patch by sagil@infinidat.com, but heavily modified.

Add a function nl_socket_set_fd(), I renamed it from nl_connect_fd().

Now nl_connect() and nl_socket_set_fd() are implemented independently as
they share little code. But they have similar functionality:
to initialize a libnl socket and set it's file descriptor.

A user who wants libnl to setup the socket can continue to use nl_connect().
A user with special requirements should setup the socket entirely. That includes
calling socket() (with or without SOCK_CLOEXEC), bind(), setting buffer size.

For the same reason I dropped nl_create_fd(). It didn't do much more then
calling socket() -- which the user can do directly.

https://github.com/thom311/libnl/pull/68

Signed-off-by: Thomas Haller <thaller@redhat.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/lib/nl.c b/lib/nl.c
index 8e4c455..8fc9ec1 100644
--- a/lib/nl.c
+++ b/lib/nl.c
@@ -86,8 +86,13 @@
  *       This capability is indicated by
  *       `%NL_CAPABILITY_NL_CONNECT_RETRY_GENERATE_PORT_ON_ADDRINUSE`.
  *
+ * @note nl_connect() creates and sets the file descriptor. You can setup the file
+ *       descriptor yourself by creating and binding it, and then calling
+ *       nl_socket_set_fd(). The result will be the same.
+ *
  * @see nl_socket_alloc()
  * @see nl_close()
+ * @see nl_socket_set_fd()
  *
  * @return 0 on success or a negative error code.
  *
@@ -105,8 +110,8 @@ int nl_connect(struct nl_sock *sk, int protocol)
 	flags |= SOCK_CLOEXEC;
 #endif
 
-        if (sk->s_fd != -1)
-                return -NLE_BAD_SOCK;
+	if (sk->s_fd != -1)
+		return -NLE_BAD_SOCK;
 
 	sk->s_fd = socket(AF_NETLINK, SOCK_RAW | flags, protocol);
 	if (sk->s_fd < 0) {