support -A to print the ascii text of captured packets. ok deraadt@

2 files changed, 40 insertions, 6 deletions

diff --git a/usr.sbin/tcpdump/tcpdump.8 b/usr.sbin/tcpdump/tcpdump.8
index 43a64ff74df..848309a0107 100644
--- a/usr.sbin/tcpdump/tcpdump.8
+++ b/usr.sbin/tcpdump/tcpdump.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: tcpdump.8,v 1.75 2011/03/28 09:37:03 jmc Exp $
+.\"	$OpenBSD: tcpdump.8,v 1.76 2012/07/10 18:07:37 sthen Exp $
 .\"
 .\" Copyright (c) 1987, 1988, 1989, 1990, 1991, 1992, 1994, 1995, 1996
 .\"	The Regents of the University of California.  All rights reserved.
@@ -19,7 +19,7 @@
 .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 .\"
-.Dd $Mdocdate: March 28 2011 $
+.Dd $Mdocdate: July 10 2012 $
 .Dt TCPDUMP 8
 .Os
 .Sh NAME
@@ -28,7 +28,7 @@
 .Sh SYNOPSIS
 .Nm tcpdump
 .Bk -words
-.Op Fl adefILlNnOopqStvXx
+.Op Fl AadefILlNnOopqStvXx
 .Op Fl c Ar count
 .Op Fl D Ar direction
 .Oo Fl E Oo Ar espalg : Oc Ns
@@ -51,6 +51,14 @@ You must have read access to
 .Pp
 The options are as follows:
 .Bl -tag -width "-c count"
+.It Fl A
+Print each packet in ASCII.
+If the
+.Fl e
+option is also specified, the link-level header will be included.
+The smaller of the entire packet or
+.Ar snaplen
+bytes will be printed.
 .It Fl a
 Attempt to convert network and broadcast addresses to names.
 .It Fl c Ar count
diff --git a/usr.sbin/tcpdump/tcpdump.c b/usr.sbin/tcpdump/tcpdump.c
index 2298c8e2de1..ecd42fd1dfa 100644
--- a/usr.sbin/tcpdump/tcpdump.c
+++ b/usr.sbin/tcpdump/tcpdump.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcpdump.c,v 1.63 2010/06/26 16:47:07 henning Exp $	*/
+/*	$OpenBSD: tcpdump.c,v 1.64 2012/07/10 18:07:37 sthen Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
@@ -59,6 +59,7 @@
 #include "pfctl_parser.h"
 #include "privsep.h"
 
+int Aflag;			/* dump ascii */
 int aflag;			/* translate network and broadcast addresses */
 int dflag;			/* print filter code */
 int eflag;			/* print ethernet header */
@@ -228,9 +229,14 @@ main(int argc, char **argv)
 
 	opterr = 0;
 	while ((op = getopt(argc, argv,
-	    "ac:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:Y")) != -1)
+	    "Aac:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:Y")) != -1)
 		switch (op) {
 
+		case 'A':
+			if (xflag == 0) ++xflag;
+			++Aflag;
+			break;
+
 		case 'a':
 			++aflag;
 			break;
@@ -597,6 +603,20 @@ default_print_hexl(const u_char *cp, unsigned int length, unsigned int offset)
 	}
 }
 
+/* dump the text from the buffer */
+void
+default_print_ascii(const u_char *cp, unsigned int length, unsigned int offset)
+{
+	int c, i;
+
+	printf("\n");
+	for (i = 0; i < length; i++) {
+		c = cp[i];
+		c = isprint(c) || isspace(c) ? c : '.';
+		putchar(c);
+	}
+}
+
 /* Like default_print() but data need not be aligned */
 void
 default_print_unaligned(register const u_char *cp, register u_int length)
@@ -607,6 +627,9 @@ default_print_unaligned(register const u_char *cp, register u_int length)
 	if (Xflag) {
 		/* dump the buffer in `emacs-hexl' style */
 		default_print_hexl(cp, length, 0);
+	} else if (Aflag) {
+		/* dump the text in the buffer */
+		default_print_ascii(cp, length, 0);
 	} else {
 		/* dump the buffer in old tcpdump style */
 		nshorts = (u_int) length / sizeof(u_short);
@@ -635,6 +658,9 @@ default_print(register const u_char *bp, register u_int length)
 	if (Xflag) {
 		/* dump the buffer in `emacs-hexl' style */
 		default_print_hexl(bp, length, 0);
+	} else if (Aflag) {
+		/* dump the text in the buffer */
+		default_print_ascii(bp, length, 0);
 	} else {
 		/* dump the buffer in old tcpdump style */
 		if ((long)bp & 1) {
@@ -674,7 +700,7 @@ __dead void
 usage(void)
 {
 	(void)fprintf(stderr,
-"Usage: %s [-adefILlNnOopqStvXx] [-c count] [-D direction]\n",
+"Usage: %s [-AadefILlNnOopqStvXx] [-c count] [-D direction]\n",
 	    program_name);
 	(void)fprintf(stderr,
 "\t       [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n");