atrf-txrx: added ability to record received frames in pcap format

- pcap.h: basic pcap file structure definitions
- atrf-txrx.c (usage, main): added option "-o file" to write received
  frames to a pcap file instead of displaying them
- atrf-txrx.c (receive): moved code to receive and display a single message
  into new function receive_message
- atrf-txrx.c (write_pcap_hdr, write_pcap_rec, receive_pcap): receive
  messages into a pcap file

tools/atrf-txrx/atrf-txrx.c

@@ -19,11 +19,14 @@
 #include <math.h>
 #include <signal.h>
 #include <sys/wait.h>
+#include <sys/time.h>
 
 #include "at86rf230.h"
 #include "atrf.h"
 #include "misctxrx.h"
 
+#include "pcap.h"
+
 
 /*
  * According to IEEE 802.15.4-2003 section E.2.6, channel 15 is the only
@@ -148,19 +151,12 @@ static void set_power(struct atrf_dsc *dsc, double power, int crc)
 }
 
 
-static void receive(struct atrf_dsc *dsc)
+static void receive_message(struct atrf_dsc *dsc)
 {
 	uint8_t buf[MAX_PSDU+1]; /* PSDU+LQI */
 	int n, ok, i;
 	uint8_t ed, lqi;
 
-	atrf_reg_write(dsc, REG_TRX_STATE, TRX_CMD_RX_ON);
-	/*
-	 * 180 us, according to AVR2001 section 4.2. We time out after
-	 * nominally 200 us.
-	 */
-	wait_for_interrupt(dsc, IRQ_PLL_LOCK, IRQ_PLL_LOCK, 10, 20);
-
 	fprintf(stderr, "Ready.\n");
 	wait_for_interrupt(dsc, IRQ_TRX_END, IRQ_TRX_END | IRQ_RX_START,
 	    10, 0);
@@ -185,6 +181,103 @@ static void receive(struct atrf_dsc *dsc)
 }
 
 
+static void write_pcap_hdr(FILE *file)
+{
+	struct pcap_file_header hdr = {
+		.magic		= 0xa1b2c3d4,
+		.version_major	= 2,
+		.version_minor	= 4,
+		.thiszone	= 0,
+		.sigfigs	= 0,
+		.snaplen	= MAX_PSDU,
+		.linktype	= DLT_IEEE802_15_4
+	};
+
+	if (fwrite(&hdr, sizeof(hdr), 1, file) != 1) {
+		perror("fwrite");
+		exit(1);
+	}
+}
+
+
+static void write_pcap_rec(FILE *file, const struct timeval *tv,
+    const void *buf, int n)
+{
+	struct pcap_pkthdr hdr = {
+		.ts_sec		= tv->tv_sec,
+		.ts_usec	= tv->tv_usec,
+		.caplen		= n,
+		.len		= n
+	};
+
+	if (fwrite(&hdr, sizeof(hdr), 1, file) != 1) {
+		perror("fwrite");
+		exit(1);
+	}
+	if (fwrite(buf, n, 1, file) != 1) {
+		perror("fwrite");
+		exit(1);
+	}
+}
+
+
+static void receive_pcap(struct atrf_dsc *dsc, const char *name)
+{
+	FILE *file;
+	uint8_t buf[MAX_PSDU+1]; /* PSDU+LQI */
+	struct timeval now;
+	int n;
+	int count = 0;
+
+	file = fopen(name, "w");
+	if (!file) {
+		perror(name);
+		exit(1);
+	}
+	write_pcap_hdr(file);
+	while (run) {
+		wait_for_interrupt(dsc,
+		    IRQ_TRX_END, IRQ_TRX_END | IRQ_RX_START,
+		    10, 0);
+		if (!run)
+			break;
+		gettimeofday(&now, NULL);
+		n = atrf_buf_read(dsc, buf, sizeof(buf));
+		if (n < 0)
+			exit(1);
+		if (n < 2) {
+			fprintf(stderr, "%d bytes received\n", n);
+			continue;
+		}
+		write_pcap_rec(file, &now, buf, n-1);
+		(void) write(2, ".", 1);
+		count++;
+	}
+	if (fclose(file) == EOF) {
+		perror(name);
+		exit(1);
+	}
+	fprintf(stderr, "%sreceived %d message%s\n", count ? "\n" : "",
+	    count, count == 1 ? "" : "s");
+}
+
+
+static void receive(struct atrf_dsc *dsc, const char *name)
+{
+	atrf_reg_write(dsc, REG_TRX_STATE, TRX_CMD_RX_ON);
+	/*
+	 * 180 us, according to AVR2001 section 4.2. We time out after
+	 * nominally 200 us.
+	 */
+	wait_for_interrupt(dsc, IRQ_PLL_LOCK, IRQ_PLL_LOCK, 10, 20);
+
+	if (name)
+		receive_pcap(dsc, name);
+	else
+		receive_message(dsc);
+}
+
+
 static void transmit(struct atrf_dsc *dsc, const char *msg, int times)
 {
 	uint8_t buf[MAX_PSDU];
@@ -332,10 +425,12 @@ static void usage(const char *name)
 "                wave in MHz: -2, -0.5, or +0.5\n"
 "    command     shell command to run while transmitting (default: wait for\n"
 "                SIGINT instead)\n\n"
-"  common options: [-c channel|-f freq] [-C mhz] [-p power] [-t trim]\n"
+"  common options: [-c channel|-f freq] [-C mhz] [-o file] [-p power] "
+"[-t trim]\n"
 "    -c channel  channel number, 11 to 26 (default %d)\n"
 "    -C mhz      output clock at 1, 2, 4, 8, or 16 MHz (default: off)\n"
 "    -f freq     frequency in MHz, 2405 to 2480 (default %d)\n"
+"    -o file     write received data to a file in pcap format\n"
 "    -p power    transmit power, -17.2 to 3.0 dBm (default %.1f)\n"
 "    -t trim     trim capacitor, 0 to 15 (default 0)\n"
 	    , name, name, DEFAULT_CHANNEL, 2405+5*(DEFAULT_CHANNEL-11),
@@ -354,9 +449,10 @@ int main(int argc, char *const *argv)
 	int c, freq;
 	unsigned tmp, clkm = 0;
 	int status = 0;
+	const char *pcap_file = NULL;
 	struct atrf_dsc *dsc;
 
-	while ((c = getopt(argc, argv, "c:C:f:p:t:T:")) != EOF)
+	while ((c = getopt(argc, argv, "c:C:f:o:p:t:T:")) != EOF)
 		switch (c) {
 		case 'c':
 			channel = strtoul(optarg, &end, 0);
@@ -375,6 +471,9 @@ int main(int argc, char *const *argv)
 			if (channel < 11 || channel > 26)
 				usage(*argv);
 			break;
+		case 'o':
+			pcap_file = optarg;
+			break;
 		case 'p':
 			power = strtod(optarg, &end);
 			if (*end)
@@ -419,7 +518,7 @@ int main(int argc, char *const *argv)
 		dsc = init_txrx(trim, clkm);
 		set_channel(dsc, channel);
 		if (!cont_tx)
-			receive(dsc);
+			receive(dsc, pcap_file);
 		else {
 			set_power(dsc, power, 0);
 			status = test_mode(dsc, cont_tx, NULL);

tools/atrf-txrx/pcap.h

@@ -0,0 +1,49 @@
+/*
+ * pcap.h - Minimum pcap file definitions
+ *
+ * Written 2011 by Werner Almesberger
+ * Copyright 2011 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+/*
+ * This header defines the few things we need to write files in the pcap
+ * format. The identifiers are the same as in the system's pcap/pcap.h, but
+ * the types have been standardized. Note that the timestamp parts have to be
+ * put separately, since "struct timeval" may be padded.
+ *
+ * The reason for having our own header instead of just using pcap/pcap.h is
+ * to avoid a build-dependency on libpcap.
+ */
+
+#ifndef PCAP_H
+#define	PCAP_H
+
+#include <stdint.h>
+#include <sys/time.h>
+
+
+#define	DLT_IEEE802_15_4	195
+
+struct pcap_file_header {
+	uint32_t magic;
+	uint16_t version_major;
+	uint16_t version_minor;
+	int32_t thiszone;
+	uint32_t sigfigs;
+	uint32_t snaplen;
+	uint32_t linktype;
+};
+
+struct pcap_pkthdr {
+	uint32_t ts_sec;
+	uint32_t ts_usec;
+	uint32_t caplen;
+	uint32_t len;
+};
+
+#endif /* !PCAP_H */