Cleanroom libnl_2 library

By overriding the netlink cache pointer, able to pass nl80211 family id.
Scan and connecting open access point work
Added legal stuff to headers

Change-Id: I1c60452f35fdd1f80edebc03fef33067722d0543
diff --git a/libnl_2/socket.c b/libnl_2/socket.c
new file mode 100644
index 0000000..1a2255e
--- /dev/null
+++ b/libnl_2/socket.c
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* NOTICE: This is a clean room re-implementation of libnl */
+
+#include <errno.h>
+#include <unistd.h>
+#include <malloc.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include "netlink-types.h"
+
+/* Join group */
+int nl_socket_add_membership(struct nl_sock *sk, int group)
+{
+	return setsockopt(sk->s_fd, SOL_NETLINK,
+			NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
+}
+
+/* Allocate new netlink socket. */
+struct nl_sock *nl_socket_alloc(void)
+{
+	struct nl_sock *sk = (struct nl_sock *) malloc(sizeof(struct nl_sock));
+	struct timeval tv;
+	struct nl_cb *cb;
+
+	if (!sk)
+		goto fail;
+
+	/* Get current time */
+
+	if (gettimeofday(&tv, NULL))
+		return NULL;
+	else
+		sk->s_seq_next = (int) tv.tv_sec;
+
+	/* Create local socket */
+	sk->s_local.nl_family = AF_NETLINK;
+	sk->s_local.nl_pid = getpid();
+	sk->s_local.nl_groups = 0; /* No groups */
+
+	/* Create peer socket */
+	sk->s_peer.nl_family = AF_NETLINK;
+	sk->s_peer.nl_pid = 0; /* Kernel */
+	sk->s_peer.nl_groups = 0; /* No groups */
+
+	cb = (struct nl_cb *) malloc(sizeof(struct nl_cb));
+	if (!cb)
+		goto cb_fail;
+	memset(cb, 0, sizeof(*cb));
+	sk->s_cb = nl_cb_alloc(NL_CB_DEFAULT);
+
+
+	return sk;
+cb_fail:
+	free(sk);
+fail:
+	return NULL;
+}
+
+/* Allocate new socket with custom callbacks. */
+struct nl_sock *nl_socket_alloc_cb(struct nl_cb *cb)
+{
+	struct nl_sock *sk = nl_socket_alloc();
+	if (!sk)
+		goto fail;
+
+	sk->s_cb = cb;
+	nl_cb_get(cb);
+
+	return sk;
+fail:
+	return NULL;
+}
+
+/* Free a netlink socket. */
+void nl_socket_free(struct nl_sock *sk)
+{
+	nl_cb_put(sk->s_cb);
+	free(sk);
+}
+
+/* Sets socket buffer size of netlink socket */
+int nl_socket_set_buffer_size(struct nl_sock *sk, int rxbuf, int txbuf)
+{
+	if (setsockopt(sk->s_fd, SOL_SOCKET, SO_SNDBUF, \
+			&rxbuf, (socklen_t) sizeof(rxbuf)))
+		goto error;
+
+	if (setsockopt(sk->s_fd, SOL_SOCKET, SO_RCVBUF, \
+			&txbuf, (socklen_t) sizeof(txbuf)))
+		goto error;
+
+	return 0;
+error:
+	return -errno;
+
+}
+
+int nl_socket_get_fd(struct nl_sock *sk)
+{
+	return sk->s_fd;
+}
+
+