wlantest: Add preliminary infrastructure for injecting frames

This adds new commands for wlantest_cli to request wlantest to
inject frames. This version can only send out Authentication
frames and unprotected SA Query Request frames, but there is
now place to add more frames and encryption with future commits.

wlantest/inject.c

@@ -0,0 +1,80 @@
+/*
+ * wlantest frame injection
+ * Copyright (c) 2010, Jouni Malinen <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ */
+
+#include "utils/includes.h"
+
+#include "utils/common.h"
+#include "wlantest.h"
+
+
+static int inject_frame(int s, const void *data, size_t len)
+{
+#define	IEEE80211_RADIOTAP_F_FRAG	0x08
+	unsigned char rtap_hdr[] = {
+		0x00, 0x00, /* radiotap version */
+		0x0e, 0x00, /* radiotap length */
+		0x02, 0xc0, 0x00, 0x00, /* bmap: flags, tx and rx flags */
+		IEEE80211_RADIOTAP_F_FRAG, /* F_FRAG (fragment if required) */
+		0x00,       /* padding */
+		0x00, 0x00, /* RX and TX flags to indicate that */
+		0x00, 0x00, /* this is the injected frame directly */
+	};
+	struct iovec iov[2] = {
+		{
+			.iov_base = &rtap_hdr,
+			.iov_len = sizeof(rtap_hdr),
+		},
+		{
+			.iov_base = (void *) data,
+			.iov_len = len,
+		}
+	};
+	struct msghdr msg = {
+		.msg_name = NULL,
+		.msg_namelen = 0,
+		.msg_iov = iov,
+		.msg_iovlen = 2,
+		.msg_control = NULL,
+		.msg_controllen = 0,
+		.msg_flags = 0,
+	};
+	int ret;
+
+	ret = sendmsg(s, &msg, 0);
+	if (ret < 0)
+		perror("sendmsg");
+	return ret;
+}
+
+
+int wlantest_inject(struct wlantest *wt, struct wlantest_bss *bss,
+		    struct wlantest_sta *sta, u8 *frame, size_t len,
+		    enum wlantest_inject_protection prot)
+{
+	int ret;
+
+	wpa_hexdump(MSG_DEBUG, "Inject frame", frame, len);
+	if (wt->monitor_sock < 0) {
+		wpa_printf(MSG_INFO, "Cannot inject frames when monitor "
+			   "interface is not in use");
+		return -1;
+	}
+
+	/* TODO: encrypt if needed */
+	if (prot != WLANTEST_INJECT_UNPROTECTED)
+		return -1;
+
+	ret = inject_frame(wt->monitor_sock, frame, len);
+	return (ret < 0) ? -1 : 0;
+}