tools/atrf-txrx/perdump: new utility to analyze a PER dump

- Makefile: added perdump
- perdump.h, perdump.c: read and analyze a PER dump in pcap format
- per-text.c: report PER test results as text on the console

tools/atrf-txrx/Makefile

@@ -1,8 +1,8 @@
 #
 # atrf-txrx/Makefile - Build the TX/RX test utility
 #
-# Written 2010 by Werner Almesberger
+# Written 2010, 2011 by Werner Almesberger
-# Copyright 2010 Werner Almesberger
+# Copyright 2010, 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
@@ -16,3 +16,11 @@ MAIN = atrf-txrx
 include ../Makefile.common
 
 LDLIBS += -lm
+CFLAGS += -g
+
+all:		perdump
+
+perdump:	perdump.o per-text.o
+
+clean::
+		rm -f perdump.o per-text.o

tools/atrf-txrx/per-text.c

@@ -0,0 +1,92 @@
+/*
+ * atrf-txrx/per-text.h - Report PER on console as text
+ *
+ * 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.
+ */
+
+
+#include <stdio.h>
+
+#include "perdump.h"
+
+
+static char line[65] = "";
+static int packets = 0, garbled = 0, bad = 0, skipped = 0;
+static int is_bad = 0;
+
+
+static void flush(void)
+{
+	if (*line)
+		printf("%s\n", line);
+	*line = 0;
+}
+
+
+static void text_undecided(int symbols)
+{
+	int i;
+
+	flush();
+	for (i = 0; i != symbols/4; i++)
+		putchar('?');
+	putchar('\n');
+}
+
+
+static void text_packet(int symbols, int skip)
+{
+	int i;
+
+	flush();
+	skipped += skip;
+	if (skip < 4)
+		for (i = 0; i != skip; i++)
+			putchar('\n');
+	else
+		printf("\n(%d)\n\n", skip);
+	for (i = 0; i != symbols/4; i++)
+		line[i] = '-';
+	line[i] = 0;
+	packets++;
+	is_bad = 0;
+}
+
+
+static void text_error(int symbol)
+{
+	line[symbol >> 2] = '*';
+	if (!is_bad) {
+		bad++;
+		is_bad = 1;
+	}
+}
+
+
+static void text_finish(void)
+{
+	double per;
+
+	flush();
+	if (packets+garbled)
+		per = (double) (bad+garbled)/(packets+garbled);
+	else
+		per = 0;
+	printf("\n%d total, %d bad, %d garbled, PER %f%%. %d skipped.\n",
+	    packets+garbled, bad, garbled, 100*per, skipped);
+}
+
+
+struct result_ops text_ops = {
+	.begin		= NULL,
+	.undecided	= text_undecided,
+	.packet		= text_packet,
+	.error		= text_error,
+	.finish		= text_finish,
+};

tools/atrf-txrx/perdump.c

@@ -0,0 +1,153 @@
+/*
+ * atrf-txrx/perdump.c - Analyze and dump a recorded PER test
+ *
+ * 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.
+ */
+
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "pcap.h"
+#include "perdump.h"
+
+
+#define	MAX_PSDU	127
+
+
+static const struct result_ops *ops;
+
+
+static void analyze(uint8_t *buf, int len)
+{
+	static int last = -1;
+	int freq[256];
+	uint8_t best = 0;
+	int i;
+
+	for (i = 0; i != 256; i++)
+		freq[i] = 0;
+	for (i = 0; i != len; i++) {
+		freq[buf[i]]++;
+		if (!i || freq[buf[i]] > freq[best])
+			best = buf[i];
+	}
+	if (freq[best] <= len >> 1 && freq[best] != len) {
+		ops->undecided(len*2);
+		if (last != -1)
+			last++;	/* probably :-) */
+		return;
+	}
+	ops->packet(len*2, last == -1 ? 0 : (uint8_t) (best-last-1));
+	last = best;
+	for (i = 0; i != len; i++) {
+		uint8_t delta = buf[i] ^ best;
+
+		if (delta & 0x0f)
+			ops->error(i*2);
+		if (delta & 0xf0)
+			ops->error(i*2+1);
+	}
+	
+}
+
+
+static int pcap_record(FILE *file, const char *name)
+{
+	struct pcap_pkthdr hdr;
+	uint8_t buf[MAX_PSDU];
+	size_t got;
+
+	got = fread(&hdr, sizeof(hdr), 1, file);
+	if (!got) {
+		if (ferror(file)) {
+			perror(name);
+			exit(1);
+		}
+		return 0;
+	}
+	if (hdr.caplen > MAX_PSDU) {
+		fprintf(stderr, "packet too big %u > %u\n",
+		    hdr.caplen, MAX_PSDU);
+		exit(1);
+	}
+	got = fread(buf, hdr.caplen, 1, file);
+	if (!got) {
+		if (ferror(file)) {
+			perror(name);
+			exit(1);
+		}
+		fprintf(stderr, "file truncated\n");
+		exit(1);
+	}
+	analyze(buf, hdr.caplen);
+	return 1;
+}
+
+
+static void process_pcap(const char *name)
+{
+	FILE *file;
+	struct pcap_file_header hdr;
+	size_t got;
+
+	file = fopen(name, "r");
+	if (!file) {
+		perror(name);
+		exit(1);
+	}
+	got = fread(&hdr, sizeof(hdr), 1, file);
+	if (!got) {
+		if (ferror(file)) {
+			perror(name);
+			exit(1);
+		}
+		return;
+		return;
+	}
+	if (hdr.magic != PCAP_FILE_MAGIC) {
+		fprintf(stderr, "unrecognized magic number 0x%08x "
+		    "(expected 0x%08x)\n", hdr.magic, PCAP_FILE_MAGIC);
+		exit(1);
+	}
+	if (hdr.version_major != 2) {
+		fprintf(stderr, "unrecognized major number %u (expected %u)\n",
+		    hdr.version_major, 2);
+		exit(1);
+	}
+	if (hdr.linktype != DLT_IEEE802_15_4) {
+		fprintf(stderr, "unrecognized link type 0x%x "
+		    "(expected 0x%0x)\n", hdr.linktype, DLT_IEEE802_15_4);
+		exit(1);
+	}
+	if (ops->begin)
+		ops->begin();
+	while (pcap_record(file, name));
+	if (ops->finish)
+		ops->finish();
+	fclose(file);
+}
+
+
+static void usage(const char *name)
+{
+	fprintf(stderr, "usage: %s pcap-file\n", name);
+	exit(1);
+}
+
+
+int main(int argc, char **argv)
+{
+	if (argc != 2)
+		usage(*argv);
+	ops = &text_ops;
+	process_pcap(argv[1]);
+	return 0;
+}

tools/atrf-txrx/perdump.h

@@ -0,0 +1,28 @@
+/*
+ * atrf-txrx/perdump.h - Analyze and dump a recorded PER test
+ *
+ * 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.
+ */
+
+
+#ifndef PERDUMP_H
+#define	PERDUMP_H
+
+struct result_ops {
+	void (*begin)(void);
+	void (*undecided)(int symbols);
+	void (*packet)(int symbols, int skip);
+	void (*error)(int symbol);
+	void (*finish)(void);
+};
+
+
+extern struct result_ops text_ops;
+
+#endif /* !PERDUMP_H */