X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/3a47232799dc8b7814ed8ac18810405b702c6c63..febd0bc5aa33b3de9b5864e8c5565fe7b63f519f:/tcpdump.c?ds=sidebyside

diff --git a/tcpdump.c b/tcpdump.c
index 4172e0d0..270f79b4 100644
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -44,9 +44,10 @@ The Regents of the University of California.  All rights reserved.\n";
 #endif
 
 /*
- * Mac OS X may ship pcap.h from libpcap 0.6 with a libpcap based on
- * 0.8.  That means it has pcap_findalldevs() but the header doesn't
- * define pcap_if_t, meaning that we can't actually *use* pcap_findalldevs().
+ * Some older versions of Mac OS X may ship pcap.h from libpcap 0.6 with a
+ * libpcap based on 0.8.  That means it has pcap_findalldevs() but the
+ * header doesn't define pcap_if_t, meaning that we can't actually *use*
+ * pcap_findalldevs().
  */
 #ifdef HAVE_PCAP_FINDALLDEVS
 #ifndef HAVE_PCAP_IF_T
@@ -113,6 +114,10 @@ The Regents of the University of California.  All rights reserved.\n";
 #endif /* HAVE_CAP_NG_H */
 #endif /* HAVE_LIBCAP_NG */
 
+#ifdef __FreeBSD__
+#include <sys/sysctl.h>
+#endif /* __FreeBSD__ */
+
 #include "netdissect.h"
 #include "interface.h"
 #include "addrtoname.h"
@@ -135,7 +140,7 @@ The Regents of the University of California.  All rights reserved.\n";
 #endif
 
 static int Bflag;			/* buffer size */
-static int Cflag;			/* rotate dump files after this many bytes */
+static long Cflag;			/* rotate dump files after this many bytes */
 static int Cflag_count;			/* Keep track of which file number we're writing */
 static int Dflag;			/* list available devices and exit */
 /*
@@ -180,26 +185,17 @@ cap_channel_t *capdns;
 #endif
 
 /* Forwards */
-static void error(const char *, ...)
-     __attribute__((noreturn))
-#ifdef __ATTRIBUTE___FORMAT_OK
-     __attribute__((format (printf, 1, 2)))
-#endif /* __ATTRIBUTE___FORMAT_OK */
-     ;
-static void warning(const char *, ...)
-#ifdef __ATTRIBUTE___FORMAT_OK
-     __attribute__((format (printf, 1, 2)))
-#endif /* __ATTRIBUTE___FORMAT_OK */
-     ;
-static void exit_tcpdump(int) __attribute__((noreturn));
+static NORETURN void error(FORMAT_STRING(const char *), ...) PRINTFLIKE(1, 2);
+static void warning(FORMAT_STRING(const char *), ...) PRINTFLIKE(1, 2);
+static NORETURN void exit_tcpdump(int);
 static RETSIGTYPE cleanup(int);
 static RETSIGTYPE child_cleanup(int);
 static void print_version(void);
 static void print_usage(void);
-static void show_tstamp_types_and_exit(pcap_t *, const char *device) __attribute__((noreturn));
-static void show_dlts_and_exit(pcap_t *, const char *device) __attribute__((noreturn));
+static NORETURN void show_tstamp_types_and_exit(pcap_t *, const char *device);
+static NORETURN void show_dlts_and_exit(pcap_t *, const char *device);
 #ifdef HAVE_PCAP_FINDALLDEVS
-static void show_devices_and_exit (void) __attribute__((noreturn));
+static NORETURN void show_devices_and_exit(void);
 #endif
 
 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
@@ -1040,10 +1036,16 @@ open_interface(const char *device, netdissect_options *ndo, char *ebuf)
 		supports_monitor_mode = 1;
 	else
 		supports_monitor_mode = 0;
-	status = pcap_set_snaplen(pc, ndo->ndo_snaplen);
-	if (status != 0)
-		error("%s: Can't set snapshot length: %s",
-		    device, pcap_statustostr(status));
+	if (ndo->ndo_snaplen != 0) {
+		/*
+		 * A snapshot length was explicitly specified;
+		 * use it.
+		 */
+		status = pcap_set_snaplen(pc, ndo->ndo_snaplen);
+		if (status != 0)
+			error("%s: Can't set snapshot length: %s",
+			    device, pcap_statustostr(status));
+	}
 	status = pcap_set_promisc(pc, !pflag);
 	if (status != 0)
 		error("%s: Can't set promiscuous mode: %s",
@@ -1084,13 +1086,37 @@ open_interface(const char *device, netdissect_options *ndo, char *ebuf)
 			/*
 			 * Return an error for our caller to handle.
 			 */
-			pcap_close(pc);
 			snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s\n(%s)",
 			    device, pcap_statustostr(status), cp);
+			pcap_close(pc);
 			return (NULL);
 		} else if (status == PCAP_ERROR_PERM_DENIED && *cp != '\0')
 			error("%s: %s\n(%s)", device,
 			    pcap_statustostr(status), cp);
+#ifdef __FreeBSD__
+		else if (status == PCAP_ERROR_RFMON_NOTSUP &&
+		    strncmp(device, "wlan", 4) == 0) {
+			char parent[8], newdev[8];
+			char sysctl[32];
+			size_t s = sizeof(parent);
+
+			snprintf(sysctl, sizeof(sysctl),
+			    "net.wlan.%d.%%parent", atoi(device + 4));
+			sysctlbyname(sysctl, parent, &s, NULL, 0);
+			strlcpy(newdev, device, sizeof(newdev));
+			/* Suggest a new wlan device. */
+			/* FIXME: incrementing the index this way is not going to work well
+			 * when the index is 9 or greater but the only consequence in this
+			 * specific case would be an error message that looks a bit odd.
+			 */
+			newdev[strlen(newdev)-1]++;
+			error("%s is not a monitor mode VAP\n"
+			    "To create a new monitor mode VAP use:\n"
+			    "  ifconfig %s create wlandev %s wlanmode monitor\n"
+			    "and use %s as the tcpdump interface",
+			    device, newdev, parent, newdev);
+		}
+#endif
 		else
 			error("%s: %s", device,
 			    pcap_statustostr(status));
@@ -1120,6 +1146,12 @@ open_interface(const char *device, netdissect_options *ndo, char *ebuf)
 #endif /* HAVE_PCAP_SETDIRECTION */
 #else /* HAVE_PCAP_CREATE */
 	*ebuf = '\0';
+	/*
+	 * If no snapshot length was specified, or a length of 0 was
+	 * specified, default to 256KB.
+	 */
+	if (ndo->ndo_snaplen == 0)
+		ndo->ndo_snaplen = 262144;
 	pc = pcap_open_live(device, ndo->ndo_snaplen, !pflag, 1000, ebuf);
 	if (pc == NULL) {
 		/*
@@ -1186,7 +1218,6 @@ main(int argc, char **argv)
 
 	memset(ndo, 0, sizeof(*ndo));
 	ndo_set_function_pointers(ndo);
-	ndo->ndo_snaplen = DEFAULT_SNAPLEN;
 
 	cnt = -1;
 	device = NULL;
@@ -1416,8 +1447,6 @@ main(int argc, char **argv)
 			if (optarg == end || *end != '\0'
 			    || ndo->ndo_snaplen < 0 || ndo->ndo_snaplen > MAXIMUM_SNAPLEN)
 				error("invalid snaplen %s", optarg);
-			else if (ndo->ndo_snaplen == 0)
-				ndo->ndo_snaplen = MAXIMUM_SNAPLEN;
 			break;
 
 		case 'S':
@@ -1755,7 +1784,8 @@ main(int argc, char **argv)
 		}
 
 		/*
-		 * Let user own process after socket has been opened.
+		 * Let user own process after capture device has
+		 * been opened.
 		 */
 #ifndef _WIN32
 		if (setgid(getgid()) != 0 || setuid(getuid()) != 0)
@@ -1790,7 +1820,11 @@ main(int argc, char **argv)
 		}
 		i = pcap_snapshot(pd);
 		if (ndo->ndo_snaplen < i) {
-			warning("snaplen raised from %d to %d", ndo->ndo_snaplen, i);
+			if (ndo->ndo_snaplen != 0)
+				warning("snaplen raised from %d to %d", ndo->ndo_snaplen, i);
+			ndo->ndo_snaplen = i;
+		} else if (ndo->ndo_snaplen > i) {
+			warning("snaplen lowered from %d to %d", ndo->ndo_snaplen, i);
 			ndo->ndo_snaplen = i;
 		}
                 if(ndo->ndo_fflag != 0) {