X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/2a13a72f0960bca64cd28bda9c6c2ee529736364..4bec97f457e593be925e92fa28d73af6a57d81cf:/tcpdump.c

diff --git a/tcpdump.c b/tcpdump.c
index 4fd5c6a7..a4dde2f3 100644
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -30,7 +30,7 @@ static const char copyright[] =
     "@(#) 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";
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/tcpdump.c,v 1.191 2002-12-19 05:44:47 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/tcpdump/tcpdump.c,v 1.193 2002-12-19 09:39:17 guy Exp $ (LBL)";
 #endif
 
 /*
@@ -62,17 +62,18 @@ extern int SIZE_BUF;
 #include <stdlib.h>
 #include <string.h>
 
-
 #include "interface.h"
 #include "addrtoname.h"
 #include "machdep.h"
 #include "setsignal.h"
 #include "gmt2local.h"
+#include "pcap-missing.h"
 
 int aflag;			/* translate network and broadcast addresses */
 int dflag;			/* print filter code */
 int eflag;			/* print ethernet header */
 int fflag;			/* don't translate "foreign" IP address */
+int Lflag;			/* list available data link types and exit */
 int nflag;			/* leave addresses as numbers */
 int Nflag;			/* remove domains from printed host names */
 int Oflag = 1;			/* run filter code optimizer */
@@ -88,13 +89,16 @@ int xflag;			/* print packet in hex */
 int Xflag;			/* print packet in ascii as well as hex */
 off_t Cflag = 0;                /* rotate dump files after this many bytes */
 int Aflag = 0;                  /* print packet only in ascii observing LF, CR, TAB, SPACE */
+int dlt = -1;		/* if != -1, ask libpcap for the DLT it names */
+
+const char *dlt_name = NULL;
 
 char *espsecret = NULL;		/* ESP secret key */
 
 int packettype;
 
-int infodelay;
-int infoprint;
+static int infodelay;
+static int infoprint;
 
 char *program_name;
 
@@ -103,7 +107,9 @@ int32_t thiszone;		/* seconds offset from gmt to local time */
 /* Forwards */
 static RETSIGTYPE cleanup(int);
 static void usage(void) __attribute__((noreturn));
+static void show_dlts_and_exit(pcap_t *pd) __attribute__((noreturn));
 
+static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
 static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 
@@ -111,11 +117,15 @@ static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 RETSIGTYPE requestinfo(int);
 #endif
 
+static void info(int);
+
 /* Length of saved portion of packet. */
 int snaplen = DEFAULT_SNAPLEN;
 
+typedef u_int (*if_printer)(const struct pcap_pkthdr *, const u_char *);
+
 struct printer {
-	pcap_handler f;
+	if_printer f;
 	int type;
 };
 
@@ -188,7 +198,7 @@ static struct printer printers[] = {
 	{ NULL,			0 },
 };
 
-static pcap_handler
+static if_printer
 lookup_printer(int type)
 {
 	struct printer *p;
@@ -197,7 +207,7 @@ lookup_printer(int type)
 		if (type == p->type)
 			return p->f;
 
-	error("unknown data link type %d", type);
+	return NULL;
 	/* NOTREACHED */
 }
 
@@ -207,23 +217,64 @@ extern int optind;
 extern int opterr;
 extern char *optarg;
 
+struct print_info {
+	if_printer printer;
+};
+
 struct dump_info {
 	char	*WFileName;
 	pcap_t	*pd;
 	pcap_dumper_t *p;
 };
 
+static void
+show_dlts_and_exit(pcap_t *pd)
+{
+	int n_dlts;
+	int *dlts = 0;
+	const char *dlt_name;
+
+	n_dlts = pcap_list_datalinks(pd, &dlts);
+	if (n_dlts < 0)
+		error("%s", pcap_geterr(pd));
+	else if (n_dlts == 0 || !dlts)
+		error("No data link types.");
+
+	(void) fprintf(stderr, "Data link types (use option -y to set):\n");
+
+	while (--n_dlts >= 0) {
+		dlt_name = pcap_datalink_val_to_name(dlts[n_dlts]);
+		if (dlt_name != NULL) {
+			(void) fprintf(stderr, "  %s", dlt_name);
+
+			/*
+			 * OK, does tcpdump handle that type?
+			 */
+			if (lookup_printer(dlts[n_dlts]) == NULL)
+				(void) fprintf(stderr, " (not supported)");
+			putchar('\n');
+		} else {
+			(void) fprintf(stderr, "  DLT %d (not supported)\n",
+			    dlts[n_dlts]);
+		}
+	}
+	free(dlts);
+	exit(0);
+}
+
 int
 main(int argc, char **argv)
 {
 	register int cnt, op, i;
 	bpf_u_int32 localnet, netmask;
 	register char *cp, *infile, *cmdbuf, *device, *RFileName, *WFileName;
-	pcap_handler printer;
+	pcap_handler callback;
+	int type;
 	struct bpf_program fcode;
 #ifndef WIN32
 	RETSIGTYPE (*oldhandler)(int);
 #endif
+	struct print_info printinfo;
 	struct dump_info dumpinfo;
 	u_char *pcap_userdata;
 	char ebuf[PCAP_ERRBUF_SIZE];
@@ -263,12 +314,12 @@ main(int argc, char **argv)
 	opterr = 0;
 	while (
 #ifdef WIN32
-	    (op = getopt(argc, argv, "aAB:c:C:dDeE:fF:i:lm:nNOpqr:Rs:StT:uvw:xXY")) != -1)
+	    (op = getopt(argc, argv, "aAB:c:C:dDeE:fF:i:lLm:nNOpqr:Rs:StT:uvw:xXy:Y")) != -1)
 #else /* WIN32 */
 #ifdef HAVE_PCAP_FINDALLDEVS
-	    (op = getopt(argc, argv, "aAc:C:dDeE:fF:i:lm:nNOpqr:Rs:StT:uvw:xXY")) != -1)
+	    (op = getopt(argc, argv, "aAc:C:dDeE:fF:i:lLm:nNOpqr:Rs:StT:uvw:xXy:Y")) != -1)
 #else /* HAVE_PCAP_FINDALLDEVS */
-	    (op = getopt(argc, argv, "aAc:C:deE:fF:i:lm:nNOpqr:Rs:StT:uvw:xXY")) != -1)
+	    (op = getopt(argc, argv, "aAc:C:deE:fF:i:lLm:nNOpqr:Rs:StT:uvw:xXy:Y")) != -1)
 #endif /* HAVE_PCAP_FINDALLDEVS */
 #endif /* WIN32 */
 		switch (op) {
@@ -277,11 +328,11 @@ main(int argc, char **argv)
 			++aflag;
 			break;
 
-               case 'A':
-                       ++xflag;
-                       ++Xflag;
-                       ++Aflag;
-                       break;
+		case 'A':
+			++xflag;
+			++Xflag;
+			++Aflag;
+			break;
 
 #ifdef WIN32
 		case 'B':
@@ -323,6 +374,10 @@ main(int argc, char **argv)
 			return 0;
 #endif /* HAVE_PCAP_FINDALLDEVS */
 
+		case 'L':
+			Lflag++;
+			break;
+
 		case 'e':
 			++eflag;
 			break;
@@ -485,6 +540,13 @@ main(int argc, char **argv)
 			++Xflag;
 			break;
 
+		case 'y':
+			dlt_name = optarg;
+			dlt = pcap_datalink_name_to_val(dlt_name);
+			if (dlt < 0)
+				error("invalid data link type %s", dlt_name);
+			break;
+
 #if defined(HAVE_PCAP_DEBUG) || defined(HAVE_YYDEBUG)
 		case 'Y':
 			{
@@ -548,6 +610,27 @@ main(int argc, char **argv)
 				error("%s", pcap_geterr(pd));
 			}
 #endif /* WIN32 */
+		if (Lflag)
+			show_dlts_and_exit(pd);
+		if (dlt >= 0) {
+#ifdef HAVE_PCAP_SET_DATALINK
+			if (pcap_set_datalink(pd, dlt) < 0)
+				error("%s", pcap_geterr(pd));
+#else
+			/*
+			 * We don't actually support changing the
+			 * data link type, so we only let them
+			 * set it to what it already is.
+			 */
+			if (dlt != pcap_datalink(pd)) {
+				error("%s is not one of the DLTs supported by this device\n",
+				    dlt_name);
+			}
+#endif
+			(void)fprintf(stderr, "%s: data link type %s\n",
+			              program_name, dlt_name);
+			(void)fflush(stderr);
+		}
 		i = pcap_snapshot(pd);
 		if (snaplen < i) {
 			warning("snaplen raised from %d to %d", snaplen, i);
@@ -594,18 +677,27 @@ main(int argc, char **argv)
 		if (p == NULL)
 			error("%s", pcap_geterr(pd));
 		if (Cflag != 0) {
-			printer = dump_packet_and_trunc;
+			callback = dump_packet_and_trunc;
 			dumpinfo.WFileName = WFileName;
 			dumpinfo.pd = pd;
 			dumpinfo.p = p;
 			pcap_userdata = (u_char *)&dumpinfo;
 		} else {
-			printer = dump_packet;
+			callback = dump_packet;
 			pcap_userdata = (u_char *)p;
 		}
 	} else {
-		printer = lookup_printer(pcap_datalink(pd));
-		pcap_userdata = 0;
+		type = pcap_datalink(pd);
+		printinfo.printer = lookup_printer(type);
+		if (printinfo.printer == NULL) {
+			dlt_name = pcap_datalink_val_to_name(type);
+			if (dlt_name != NULL)
+				error("unsupported data link type %s", dlt_name);
+			else
+				error("unsupported data link type %d", type);
+		}
+		callback = print_packet;
+		pcap_userdata = (u_char *)&printinfo;
 	}
 #ifdef SIGINFO
 	(void)setsignal(SIGINFO, requestinfo);
@@ -617,7 +709,7 @@ main(int argc, char **argv)
 		(void)fflush(stderr);
 	}
 #endif /* WIN32 */
-	if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) {
+	if (pcap_loop(pd, cnt, callback, pcap_userdata) < 0) {
 		(void)fprintf(stderr, "%s: pcap_loop: %s\n",
 		    program_name, pcap_geterr(pd));
 		cleanup(0);
@@ -645,7 +737,7 @@ cleanup(int signo)
 		exit(0);
 }
 
-void
+static void
 info(register int verbose)
 {
 	struct pcap_stat stat;
@@ -743,6 +835,53 @@ dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 		info(0);
 }
 
+static void
+print_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
+{
+	struct print_info *print_info;
+	u_int hdrlen;
+
+	++infodelay;
+	ts_print(&h->ts);
+
+	print_info = (struct print_info *)user;
+
+	/*
+	 * Some printers want to check that they're not walking off the
+	 * end of the packet.
+	 * Rather than pass it all the way down, we set this global.
+	 */
+	snapend = sp + h->caplen;
+
+	hdrlen = (*print_info->printer)(h, sp);
+	if (xflag) {
+		/*
+		 * Print the raw packet data.
+		 */
+		if (xflag > 1) {
+			/*
+			 * Include the link-layer header.
+			 */
+			default_print_unaligned(sp, h->caplen);
+		} else {
+			/*
+			 * Don't include the link-layer header - and if
+			 * we have nothing past the link-layer header,
+			 * print nothing.
+			 */
+			if (h->caplen > hdrlen)
+				default_print_unaligned(sp + hdrlen,
+				    h->caplen - hdrlen);
+		}
+	}
+
+	putchar('\n');
+
+	--infodelay;
+	if (infoprint)
+		info(0);
+}
+
 /* Like default_print() but data need not be aligned */
 void
 default_print_unaligned(register const u_char *cp, register u_int length)
@@ -803,31 +942,6 @@ default_print(register const u_char *bp, register u_int length)
 	default_print_unaligned(bp, length);
 }
 
-/*
- * By default, print the packet out in hex; if eflag is set, print
- * everything, otherwise print everything except for the link-layer
- * header.
- */
-void
-default_print_packet(register const u_char *bp, register u_int length,
-    u_int hdr_length)
-{
-	if (xflag > 1) {
-		/*
-		 * Include the link-layer header.
-		 */
-		default_print_unaligned(bp, length);
-	} else {
-		/*
-		 * Don't include the link-layer header - and if we have
-		 * nothing past the link-layer header, print nothing.
-		 */
-		if (length > hdr_length)
-			default_print_unaligned(bp + hdr_length,
-			    length - hdr_length);
-	}
-}
-
 #ifdef SIGINFO
 RETSIGTYPE requestinfo(int signo _U_)
 {
@@ -857,17 +971,19 @@ usage(void)
 #endif /* WIN32 */
 	(void)fprintf(stderr,
 #ifdef WIN32
-"Usage: %s [-aAdDeflnNOpqRStuvxX] [-B size] [-c count] [ -C file_size ]\n", program_name);
+"Usage: %s [-aAdDeflLnNOpqRStuvxX] [-B size] [-c count] [ -C file_size ]\n", program_name);
 #else /* WIN32 */
 #ifdef HAVE_PCAP_FINDALLDEVS
-"Usage: %s [-aAdDeflnNOpqRStuvxX] [-c count] [ -C file_size ]\n", program_name);
+"Usage: %s [-aAdDeflLnNOpqRStuvxX] [-c count] [ -C file_size ]\n", program_name);
 #else /* HAVE_PCAP_FINDALLDEVS */
-"Usage: %s [-aAdeflnNOpqRStuvxX] [-c count] [ -C file_size ]\n", program_name);
+"Usage: %s [-aAdeflLnNOpqRStuvxX] [-c count] [ -C file_size ]\n", program_name);
 #endif /* HAVE_PCAP_FINDALLDEVS */
 #endif /* WIN32 */
 	(void)fprintf(stderr,
-"\t\t[ -F file ] [ -i interface ] [ -r file ] [ -s snaplen ]\n");
+"\t\t[ -E algo:secret ] [ -F file ] [ -i interface ] [ -r file ]\n");
+	(void)fprintf(stderr,
+"\t\t[ -s snaplen ] [ -T type ] [ -w file ] [ -y datalinktype ]\n");
 	(void)fprintf(stderr,
-"\t\t[ -T type ] [ -w file ] [ -E algo:secret ] [ expression ]\n");
+"\t\t[ expression ]\n");
 	exit(1);
 }