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

1 files changed, 153 insertions, 0 deletions

diff --git a/libnl_2/msg.c b/libnl_2/msg.c
new file mode 100644
index 0000000..d7276b7
--- /dev/null
+++ b/libnl_2/msg.c
@@ -0,0 +1,153 @@
+/*
+ * 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 <malloc.h>
+#include <unistd.h>
+#include <linux/netlink.h>
+#include "netlink-types.h"
+
+/* Allocate a new netlink message with the default maximum payload size. */
+struct nl_msg *nlmsg_alloc(void)
+{
+	/* Whole page will store nl_msg + nlmsghdr + genlmsghdr + payload */
+	const int page_sz = getpagesize();
+	struct nl_msg *nm;
+	struct nlmsghdr *nlh;
+
+	/* Netlink message */
+	nm = (struct nl_msg *) malloc(page_sz);
+	if (!nm)
+		goto fail;
+
+	/* Netlink message header pointer */
+	nlh = (struct nlmsghdr *) ((char *) nm + sizeof(struct nl_msg));
+
+	/* Initialize */
+	memset(nm, 0, page_sz);
+	nm->nm_size = page_sz;
+
+	nm->nm_src.nl_family = AF_NETLINK;
+	nm->nm_src.nl_pid = getpid();
+
+	nm->nm_dst.nl_family = AF_NETLINK;
+	nm->nm_dst.nl_pid = 0; /* Kernel */
+
+	/* Initialize and add to netlink message */
+	nlh->nlmsg_len = NLMSG_HDRLEN;
+	nm->nm_nlh = nlh;
+
+	/* Add to reference count and return nl_msg */
+	nlmsg_get(nm);
+	return nm;
+fail:
+	return NULL;
+}
+
+/* Return pointer to message payload. */
+void *nlmsg_data(const struct nlmsghdr *nlh)
+{
+	return (char *) nlh + NLMSG_HDRLEN;
+}
+
+/* Add reference count to nl_msg */
+void nlmsg_get(struct nl_msg *nm)
+{
+	nm->nm_refcnt++;
+}
+
+/* Release a reference from an netlink message. */
+void nlmsg_free(struct nl_msg *nm)
+{
+	if (nm) {
+		nm->nm_refcnt--;
+		if (nm->nm_refcnt <= 0)
+			free(nm);
+	}
+
+}
+
+/* Return actual netlink message. */
+struct nlmsghdr *nlmsg_hdr(struct nl_msg *n)
+{
+	return n->nm_nlh;
+}
+
+/* Return head of attributes data / payload section */
+struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh, int hdrlen)
+{
+	unsigned char *data = nlmsg_data(nlh);
+	return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
+}
+
+/* Returns pointer to end of netlink message */
+void *nlmsg_tail(const struct nlmsghdr *nlh)
+{
+	return (void *)((char *) nlh + nlh->nlmsg_len);
+}
+
+/* Next netlink message in message stream */
+struct nlmsghdr *nlmsg_next(struct nlmsghdr *nlh, int *remaining)
+{
+	struct nlmsghdr *next_nlh = NULL;
+	if (*remaining > 0 &&
+		nlmsg_len(nlh) <= *remaining &&
+		nlmsg_len(nlh) >= (int) sizeof(struct nlmsghdr)) {
+		next_nlh = (struct nlmsghdr *) \
+			((char *) nlh + nlmsg_len(nlh));
+
+		if (next_nlh && nlmsg_len(nlh) <= *remaining) {
+			*remaining -= nlmsg_len(nlh);
+			next_nlh = (struct nlmsghdr *) \
+				((char *) nlh + nlmsg_len(nlh));
+		}
+	}
+
+	return next_nlh;
+}
+
+/* Length of attributes data */
+int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
+{
+	return nlmsg_len(nlh) - NLMSG_HDRLEN - hdrlen;
+}
+
+/* Length of netlink message */
+int nlmsg_len(const struct nlmsghdr *nlh)
+{
+	return nlh->nlmsg_len;
+}
+
+/* Check if the netlink message fits into the remaining bytes */
+int nlmsg_ok(const struct nlmsghdr *nlh, int rem)
+{
+	return rem >= (int)sizeof(struct nlmsghdr) &&
+		rem >= nlmsg_len(nlh) &&
+		nlmsg_len(nlh) >= (int) sizeof(struct nlmsghdr) &&
+		nlmsg_len(nlh) <= (rem);
+}
+
+int nlmsg_padlen(int payload)
+{
+	return NLMSG_ALIGN(payload) - payload;
+}
+
+int nlmsg_datalen(const struct nlmsghdr *nlh)
+{
+	return nlh->nlmsg_len - NLMSG_HDRLEN;
+}
+