1 files changed, 223 insertions, 0 deletions
diff --git a/mac80211.c b/mac80211.c
new file mode 100644
index 0000000..14bcc93
--- /dev/null
+++ b/mac80211.c
@@ -0,0 +1,223 @@
+/*
+ * netsniff-ng - the packet sniffing beast
+ * Copyright 2012 Daniel Borkmann.
+ * Subject to the GPL, version 2.
+ * Parts derived from iw, subject to ISC license.
+ * Copyright 2007, 2008	Johannes Berg
+ * Copyright 2007 Andy Lutomirski
+ * Copyright 2007 Mike Kershaw
+ * Copyright 2008-2009 Luis R. Rodriguez
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <limits.h>
+#include <linux/nl80211.h>
+#include <libnl3/netlink/genl/genl.h>
+#include <libnl3/netlink/genl/family.h>
+#include <libnl3/netlink/genl/ctrl.h>
+#include <libnl3/netlink/msg.h>
+#include <libnl3/netlink/attr.h>
+
+#include "die.h"
+#include "xutils.h"
+#include "mac80211.h"
+#include "xmalloc.h"
+#include "built_in.h"
+
+struct nl80211_state {
+	struct nl_sock *nl_sock;
+	struct nl_cache *nl_cache;
+	struct genl_family *nl80211;
+};
+
+static void get_mac80211_phydev(const char *device, char *phydev_path,
+				size_t phydev_len)
+{
+	int ret;
+	char *pathstr;
+	ssize_t num;
+
+	ret = asprintf(&pathstr, "/sys/class/net/%s/phy80211", device);
+	if (ret < 0)
+		panic("Can't generate path name string for /sys/class/net device");
+
+	num = readlink(pathstr, phydev_path, phydev_len);
+	if (num < 0) {
+		if (errno == ENOENT || errno == EINVAL)
+			panic("It's probably not a mac80211 device!\n");
+		panic("Can't readlink %s: %s!\n", pathstr, strerror(errno));
+	}
+
+	xfree(pathstr);
+	phydev_path[min(num, phydev_len - 1)] = 0;
+}
+
+static inline struct nl_msg *nl80211_nlmsg_xalloc(void)
+{
+	struct nl_msg *ret = nlmsg_alloc();
+	if (!ret)
+		panic("Cannot allocate nlmsg memory!\n");
+	return ret;
+}
+
+static inline struct nl_sock *nl80211_nl_socket_xalloc(void)
+{
+	struct nl_sock *ret = nl_socket_alloc();
+	if (!ret)
+		panic("Cannot allocate nl socket memory!\n");
+	return ret;
+}
+
+static void nl80211_init(struct nl80211_state *state, const char *device)
+{
+	int ret;
+
+	state->nl_sock = nl80211_nl_socket_xalloc();
+
+	ret = genl_connect(state->nl_sock);
+	if (ret)
+		panic("Cannot connect generic netlink!\n");
+
+	ret = genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache);
+	if (ret < 0)
+		panic("Failed to allocate generic netlink cache: %s!",
+		      nl_geterror(-ret));
+
+	state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211");
+	if (!state->nl80211)
+		panic("nl80211 not found in netlink cache!\n");
+}
+
+static void nl80211_cleanup(struct nl80211_state *state)
+{
+	genl_family_put(state->nl80211);
+
+	nl_cache_free(state->nl_cache);
+	nl_socket_free(state->nl_sock);
+}
+
+static int nl80211_add_mon_if(struct nl80211_state *state, const char *device,
+			      const char *mondevice)
+{
+	int ifindex, ret;
+	struct nl_msg *msg;
+
+	ifindex = device_ifindex(device);
+
+	msg = nl80211_nlmsg_xalloc();
+
+	genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
+		    0, NL80211_CMD_NEW_INTERFACE, 0);
+
+	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
+	NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice);
+	NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR);
+
+	ret = nl_send_auto_complete(state->nl_sock, msg);
+	if (ret < 0) {
+		if (ret == -ENFILE) {
+			nlmsg_free(msg);
+			return -EBUSY;
+		}
+
+		panic("Cannot send_auto_complete!\n");
+	}
+
+	ret = nl_wait_for_ack(state->nl_sock);
+	if (ret < 0) {
+		if (ret == -ENFILE) {
+			nlmsg_free(msg);
+			return -EBUSY;
+		}
+
+		panic("Waiting for netlink ack failed!\n");
+	}
+
+	nlmsg_free(msg);
+	return 0;
+
+nla_put_failure:
+	panic("nla put failure!\n");
+	return -EIO; /* dummy */
+}
+
+static int nl80211_del_mon_if(struct nl80211_state *state, const char *device,
+			      const char *mondevice)
+{
+	int ifindex, ret;
+	struct nl_msg *msg;
+
+	ifindex = device_ifindex(mondevice);
+
+	msg = nl80211_nlmsg_xalloc();
+
+	genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0,
+		    0, NL80211_CMD_DEL_INTERFACE, 0);
+
+	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex);
+
+	ret = nl_send_auto_complete(state->nl_sock, msg);
+	if (ret < 0)
+		panic("Cannot send_auto_complete!\n");
+
+	ret = nl_wait_for_ack(state->nl_sock);
+	if (ret < 0)
+		panic("Waiting for netlink ack failed!\n");
+
+	nlmsg_free(msg);
+	return 0;
+
+nla_put_failure:
+	panic("nla put failure!\n");
+	return -EIO; /* dummy */
+}
+
+void enter_rfmon_mac80211(const char *device, char **mondev)
+{
+	int ret;
+	short flags;
+	uint32_t n;
+	char phydev_path[256];
+	struct nl80211_state nlstate;
+
+	/* XXX: is this already a monN device? */
+	get_mac80211_phydev(device, phydev_path, sizeof(phydev_path));
+	nl80211_init(&nlstate, device);
+
+	for (n = 0; n < UINT_MAX; n++) {
+		char mondevice[32];
+
+		slprintf(mondevice, sizeof(mondevice), "mon%u", n);
+		ret = nl80211_add_mon_if(&nlstate, device, mondevice);
+		if (ret == 0) {
+			*mondev = xstrdup(mondevice);
+
+			flags = device_get_flags(*mondev);
+			flags |= IFF_UP | IFF_RUNNING;
+			device_set_flags(*mondev, flags);
+
+			nl80211_cleanup(&nlstate);
+			return;
+		}
+	}
+
+	panic("No free monN interfaces!\n");
+}
+
+void leave_rfmon_mac80211(const char *device, const char *mondev)
+{
+	short flags;
+	struct nl80211_state nlstate;
+
+	flags = device_get_flags(mondev);
+	flags &= ~(IFF_UP | IFF_RUNNING);
+	device_set_flags(mondev, flags);
+
+	nl80211_init(&nlstate, device);
+	nl80211_del_mon_if(&nlstate, device, mondev);
+	nl80211_cleanup(&nlstate);
+}