Support AirPcap devices with a pcap module.

This allows us to update the support for newer APIs in the future - and
in the present, with pcap_set_datalink() - and would allow Npcap to
remove its AirPcap support.

Add another test program, while we're at it.

1 files changed, 360 insertions, 0 deletions

diff --git a/testprogs/writecaptest.c b/testprogs/writecaptest.c
new file mode 100644
index 00000000..947904a3
--- /dev/null
+++ b/testprogs/writecaptest.c
@@ -0,0 +1,360 @@
+/*
+ * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code distributions
+ * retain the above copyright notice and this paragraph in its entirety, (2)
+ * distributions including binary code include the above copyright notice and
+ * this paragraph in its entirety in the documentation or other materials
+ * provided with the distribution, and (3) all advertising materials mentioning
+ * features or use of this software display the following acknowledgement:
+ * ``This product includes software developed by the University of California,
+ * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
+ * the University nor the names of its contributors may be used to endorse
+ * or promote products derived from this software without specific prior
+ * written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "varattrs.h"
+
+#ifndef lint
+static const char copyright[] _U_ =
+    "@(#) Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000\n\
+The Regents of the University of California.  All rights reserved.\n";
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <limits.h>
+#ifdef _WIN32
+  #include "getopt.h"
+#else
+  #include <unistd.h>
+#endif
+#include <errno.h>
+#ifndef _WIN32
+  #include <signal.h>
+#endif
+#include <sys/types.h>
+
+#include <pcap.h>
+
+#include "pcap/funcattrs.h"
+
+#ifdef _WIN32
+  #include "portability.h"
+#endif
+
+static char *program_name;
+
+/* Forwards */
+static void PCAP_NORETURN usage(void);
+static void PCAP_NORETURN error(const char *, ...) PCAP_PRINTFLIKE(1, 2);
+static void warning(const char *, ...) PCAP_PRINTFLIKE(1, 2);
+static char *copy_argv(char **);
+
+static pcap_t *pd;
+
+#ifdef _WIN32
+static BOOL WINAPI
+stop_capture(DWORD ctrltype _U_)
+{
+	pcap_breakloop(pd);
+	return TRUE;
+}
+#else
+static void
+stop_capture(int signum _U_)
+{
+	pcap_breakloop(pd);
+}
+#endif
+
+#define COMMAND_OPTIONS	"Li:w:y:"
+
+int
+main(int argc, char **argv)
+{
+	register int op;
+	register char *cp, *cmdbuf, *device, *savefile;
+	pcap_if_t *devlist;
+	int show_dlt_types = 0;
+	int ndlts;
+	int *dlts;
+	bpf_u_int32 localnet, netmask;
+	struct bpf_program fcode;
+	char ebuf[PCAP_ERRBUF_SIZE];
+#ifndef _WIN32
+	struct sigaction action;
+#endif
+	int dlt;
+	const char *dlt_name = NULL;
+	int status;
+	pcap_dumper_t *pdd;
+
+	device = NULL;
+	if ((cp = strrchr(argv[0], '/')) != NULL)
+		program_name = cp + 1;
+	else
+		program_name = argv[0];
+
+	opterr = 0;
+	while ((op = getopt(argc, argv, COMMAND_OPTIONS)) != -1) {
+		switch (op) {
+
+		case 'L':
+			show_dlt_types = 1;
+			break;
+
+		case 'i':
+			device = optarg;
+			break;
+
+		case 'w':
+			savefile = optarg;
+			break;
+
+		case 'y':
+			dlt_name = optarg;
+			break;
+
+		default:
+			usage();
+			/* NOTREACHED */
+		}
+	}
+
+	if (device == NULL) {
+		if (pcap_findalldevs(&devlist, ebuf) == -1)
+			error("%s", ebuf);
+		if (devlist == NULL)
+			error("no interfaces available for capture");
+		device = strdup(devlist->name);
+		pcap_freealldevs(devlist);
+	}
+	if (show_dlt_types) {
+		pd = pcap_create(device, ebuf);
+		if (pd == NULL)
+			error("%s", ebuf);
+		status = pcap_activate(pd);
+		if (status < 0) {
+			/*
+			 * pcap_activate() failed.
+			 */
+			error("%s: %s\n(%s)", device,
+			    pcap_statustostr(status), pcap_geterr(pd));
+		}
+		ndlts = pcap_list_datalinks(pd, &dlts);
+		if (ndlts < 0) {
+			/*
+			 * pcap_list_datalinks() failed.
+			 */
+			error("%s: %s\n(%s)", device,
+			    pcap_statustostr(status), pcap_geterr(pd));
+		}
+		for (int i = 0; i < ndlts; i++) {
+			dlt_name = pcap_datalink_val_to_name(dlts[i]);
+			if (dlt_name == NULL)
+				printf("DLT %d", dlts[i]);
+			else
+				printf("%s", dlt_name);
+			printf("\n");
+		}
+		pcap_free_datalinks(dlts);
+		pcap_close(pd);
+		return 0;
+	}
+		
+	if (savefile == NULL)
+		error("no savefile specified");
+
+	*ebuf = '\0';
+
+	pd = pcap_create(device, ebuf);
+	if (pd == NULL)
+		error("%s", ebuf);
+	status = pcap_set_snaplen(pd, 262144);
+	if (status != 0)
+		error("%s: pcap_set_snaplen failed: %s",
+			    device, pcap_statustostr(status));
+	status = pcap_set_timeout(pd, 100);
+	if (status != 0)
+		error("%s: pcap_set_timeout failed: %s",
+		    device, pcap_statustostr(status));
+	status = pcap_activate(pd);
+	if (status < 0) {
+		/*
+		 * pcap_activate() failed.
+		 */
+		error("%s: %s\n(%s)", device,
+		    pcap_statustostr(status), pcap_geterr(pd));
+	} else if (status > 0) {
+		/*
+		 * pcap_activate() succeeded, but it's warning us
+		 * of a problem it had.
+		 */
+		warning("%s: %s\n(%s)", device,
+		    pcap_statustostr(status), pcap_geterr(pd));
+	}
+	if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
+		localnet = 0;
+		netmask = 0;
+		warning("%s", ebuf);
+	}
+
+	if (dlt_name != NULL) {
+		dlt = pcap_datalink_name_to_val(dlt_name);
+		if (dlt == PCAP_ERROR)
+			error("%s isn't a valid DLT name", dlt_name);
+		if (pcap_set_datalink(pd, dlt) == PCAP_ERROR)
+			error("%s: %s", device, pcap_geterr(pd));
+	}
+
+	cmdbuf = copy_argv(&argv[optind]);
+
+	if (pcap_compile(pd, &fcode, cmdbuf, 1, netmask) < 0)
+		error("%s", pcap_geterr(pd));
+
+	if (pcap_setfilter(pd, &fcode) < 0)
+		error("%s", pcap_geterr(pd));
+
+	pdd = pcap_dump_open(pd, savefile);
+	if (pdd == NULL)
+		error("%s", pcap_geterr(pd));
+
+#ifdef _WIN32
+	SetConsoleCtrlHandler(stop_capture, TRUE);
+#else
+	action.sa_handler = stop_capture;
+	sigemptyset(&action.sa_mask);
+	action.sa_flags = 0;
+	if (sigaction(SIGINT, &action, NULL) == -1)
+		error("Can't catch SIGINT: %s\n", strerror(errno));
+#endif
+
+	printf("Listening on %s, link-type ", device);
+	dlt = pcap_datalink(pd);
+	dlt_name = pcap_datalink_val_to_name(dlt);
+	if (dlt_name == NULL)
+		printf("DLT %d", dlt);
+	else
+		printf("%s", dlt_name);
+	printf("\n");
+	for (;;) {
+		status = pcap_dispatch(pd, -1, pcap_dump, (u_char *)pdd);
+		if (status < 0)
+			break;
+		if (status != 0) {
+			printf("%d packets seen\n", status);
+			struct pcap_stat ps;
+			pcap_stats(pd, &ps);
+			printf("%d ps_recv, %d ps_drop, %d ps_ifdrop\n",
+			    ps.ps_recv, ps.ps_drop, ps.ps_ifdrop);
+		}
+	}
+	if (status == -2) {
+		/*
+		 * We got interrupted, so perhaps we didn't
+		 * manage to finish a line we were printing.
+		 * Print an extra newline, just in case.
+		 */
+		putchar('\n');
+		printf("Broken out of loop from SIGINT handler\n");
+	}
+	(void)fflush(stdout);
+	if (status == -1) {
+		/*
+		 * Error.  Report it.
+		 */
+		(void)fprintf(stderr, "%s: pcap_dispatch: %s\n",
+		    program_name, pcap_geterr(pd));
+	}
+	pcap_close(pd);
+	pcap_freecode(&fcode);
+	free(cmdbuf);
+	exit(status == -1 ? 1 : 0);
+}
+
+static void
+usage(void)
+{
+	(void)fprintf(stderr, "Usage: %s -L [ -i interface ] [ -w file ] [ -y dlt ] [expression]\n",
+	    program_name);
+	exit(1);
+}
+
+/* VARARGS */
+static void
+error(const char *fmt, ...)
+{
+	va_list ap;
+
+	(void)fprintf(stderr, "%s: ", program_name);
+	va_start(ap, fmt);
+	(void)vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	if (*fmt) {
+		fmt += strlen(fmt);
+		if (fmt[-1] != '\n')
+			(void)fputc('\n', stderr);
+	}
+	exit(1);
+	/* NOTREACHED */
+}
+
+/* VARARGS */
+static void
+warning(const char *fmt, ...)
+{
+	va_list ap;
+
+	(void)fprintf(stderr, "%s: WARNING: ", program_name);
+	va_start(ap, fmt);
+	(void)vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	if (*fmt) {
+		fmt += strlen(fmt);
+		if (fmt[-1] != '\n')
+			(void)fputc('\n', stderr);
+	}
+}
+
+/*
+ * Copy arg vector into a new buffer, concatenating arguments with spaces.
+ */
+static char *
+copy_argv(register char **argv)
+{
+	register char **p;
+	register size_t len = 0;
+	char *buf;
+	char *src, *dst;
+
+	p = argv;
+	if (*p == 0)
+		return 0;
+
+	while (*p)
+		len += strlen(*p++) + 1;
+
+	buf = (char *)malloc(len);
+	if (buf == NULL)
+		error("copy_argv: malloc");
+
+	p = argv;
+	dst = buf;
+	while ((src = *p++) != NULL) {
+		while ((*dst++ = *src++) != '\0')
+			;
+		dst[-1] = ' ';
+	}
+	dst[-1] = '\0';
+
+	return buf;
+}