]> The Tcpdump Group git mirrors - tcpdump/blobdiff - tcpdump.c
Avoid using a global variable when it's not needed
[tcpdump] / tcpdump.c
index 657158e4e678c153f75f982656ccccbce44bd882..b76b426d691be1ceaf12862316a26772c9ba67ab 100644 (file)
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -129,6 +129,7 @@ The Regents of the University of California.  All rights reserved.\n";
 #define SIGNAL_REQ_INFO SIGUSR1
 #endif
 
+static int Bflag;                      /* buffer size */
 static int 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 */
@@ -153,13 +154,16 @@ static int Iflag;                 /* rfmon (monitor) mode */
 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
 static int Jflag;                      /* list available time stamp types */
 #endif
+static int jflag = -1;                 /* packet time stamp source */
+static int pflag;                      /* don't go promiscuous */
 #ifdef HAVE_PCAP_SETDIRECTION
-int Qflag = -1;                                /* restrict captured packet by send/receive direction */
+static int Qflag = -1;                 /* restrict captured packet by send/receive direction */
 #endif
 static int Uflag;                      /* "unbuffered" output of dump files */
 static int Wflag;                      /* recycle output files after this number of files */
 static int WflagChars;
 static char *zflag = NULL;             /* compress each savefile using a specified command (like gzip or bzip2) */
+static int immediate_mode;
 
 static int infodelay;
 static int infoprint;
@@ -183,8 +187,11 @@ 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(const char *device) __attribute__((noreturn));
-static void show_dlts_and_exit(const char *device) __attribute__((noreturn));
+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));
+#ifdef HAVE_PCAP_FINDALLDEVS
+static void show_devices_and_exit (void) __attribute__((noreturn));
+#endif
 
 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 *);
@@ -206,6 +213,7 @@ RETSIGTYPE requestinfo(int);
 static void info(int);
 static u_int packets_captured;
 
+#ifdef HAVE_PCAP_FINDALLDEVS
 static const struct tok status_flags[] = {
 #ifdef PCAP_IF_UP
        { PCAP_IF_UP,       "Up"       },
@@ -216,6 +224,7 @@ static const struct tok status_flags[] = {
        { PCAP_IF_LOOPBACK, "Loopback" },
        { 0, NULL }
 };
+#endif
 
 static pcap_t *pd;
 
@@ -331,16 +340,16 @@ exit_tcpdump(int status)
 
 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
 static void
-show_tstamp_types_and_exit(const char *device)
+show_tstamp_types_and_exit(pcap_t *pc, const char *device)
 {
        int n_tstamp_types;
        int *tstamp_types = 0;
        const char *tstamp_type_name;
        int i;
 
-       n_tstamp_types = pcap_list_tstamp_types(pd, &tstamp_types);
+       n_tstamp_types = pcap_list_tstamp_types(pc, &tstamp_types);
        if (n_tstamp_types < 0)
-               error("%s", pcap_geterr(pd));
+               error("%s", pcap_geterr(pc));
 
        if (n_tstamp_types == 0) {
                fprintf(stderr, "Time stamp type cannot be set for %s\n",
@@ -364,15 +373,15 @@ show_tstamp_types_and_exit(const char *device)
 #endif
 
 static void
-show_dlts_and_exit(const char *device)
+show_dlts_and_exit(pcap_t *pc, const char *device)
 {
        int n_dlts, i;
        int *dlts = 0;
        const char *dlt_name;
 
-       n_dlts = pcap_list_datalinks(pd, &dlts);
+       n_dlts = pcap_list_datalinks(pc, &dlts);
        if (n_dlts < 0)
-               error("%s", pcap_geterr(pd));
+               error("%s", pcap_geterr(pc));
        else if (n_dlts == 0 || !dlts)
                error("No data link types.");
 
@@ -822,7 +831,7 @@ copy_argv(register char **argv)
        char *src, *dst;
 
        p = argv;
-       if (*p == 0)
+       if (*p == NULL)
                return 0;
 
        while (*p)
@@ -889,6 +898,208 @@ read_infile(char *fname)
        return (cp);
 }
 
+#ifdef HAVE_PCAP_FINDALLDEVS
+static long
+parse_interface_number(const char *device)
+{
+       long devnum;
+       char *end;
+
+       devnum = strtol(device, &end, 10);
+       if (device != end && *end == '\0') {
+               /*
+                * It's all-numeric, but is it a valid number?
+                */
+               if (devnum <= 0) {
+                       /*
+                        * No, it's not an ordinal.
+                        */
+                       error("Invalid adapter index");
+               }
+               return (devnum);
+       } else {
+               /*
+                * It's not all-numeric; return -1, so our caller
+                * knows that.
+                */
+               return (-1);
+       }
+}
+
+static char *
+find_interface_by_number(long devnum)
+{
+       pcap_if_t *dev, *devlist;
+       long i;
+       char ebuf[PCAP_ERRBUF_SIZE];
+       char *device;
+
+       if (pcap_findalldevs(&devlist, ebuf) < 0)
+               error("%s", ebuf);
+       /*
+        * Look for the devnum-th entry in the list of devices (1-based).
+        */
+       for (i = 0, dev = devlist; i < devnum-1 && dev != NULL;
+           i++, dev = dev->next)
+               ;
+       if (dev == NULL)
+               error("Invalid adapter index");
+       device = strdup(dev->name);
+       pcap_freealldevs(devlist);
+       return (device);
+}
+#endif
+
+static pcap_t *
+open_interface(const char *device, netdissect_options *ndo, char *ebuf)
+{
+       pcap_t *pc;
+#ifdef HAVE_PCAP_CREATE
+       int status;
+       char *cp;
+#endif
+
+#ifdef HAVE_PCAP_CREATE
+       pc = pcap_create(device, ebuf);
+       if (pc == NULL) {
+               /*
+                * If this failed with "No such device", that means
+                * the interface doesn't exist; return NULL, so that
+                * the caller can see whether the device name is
+                * actually an interface index.
+                */
+               if (strstr(ebuf, "No such device") != NULL)
+                       return (NULL);
+               error("%s", ebuf);
+       }
+#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
+       if (Jflag)
+               show_tstamp_types_and_exit(pc, device);
+#endif
+#ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
+       status = pcap_set_tstamp_precision(pc, ndo->ndo_tstamp_precision);
+       if (status != 0)
+               error("%s: Can't set %ssecond time stamp precision: %s",
+                       device,
+                       tstamp_precision_to_string(ndo->ndo_tstamp_precision),
+                       pcap_statustostr(status));
+#endif
+
+#ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
+       if (immediate_mode) {
+               status = pcap_set_immediate_mode(pc, 1);
+               if (status != 0)
+                       error("%s: Can't set immediate mode: %s",
+                       device,
+                       pcap_statustostr(status));
+       }
+#endif
+       /*
+        * Is this an interface that supports monitor mode?
+        */
+       if (pcap_can_set_rfmon(pc) == 1)
+               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));
+       status = pcap_set_promisc(pc, !pflag);
+       if (status != 0)
+               error("%s: Can't set promiscuous mode: %s",
+                   device, pcap_statustostr(status));
+       if (Iflag) {
+               status = pcap_set_rfmon(pc, 1);
+               if (status != 0)
+                       error("%s: Can't set monitor mode: %s",
+                           device, pcap_statustostr(status));
+       }
+       status = pcap_set_timeout(pc, 1000);
+       if (status != 0)
+               error("%s: pcap_set_timeout failed: %s",
+                   device, pcap_statustostr(status));
+       if (Bflag != 0) {
+               status = pcap_set_buffer_size(pc, Bflag);
+               if (status != 0)
+                       error("%s: Can't set buffer size: %s",
+                           device, pcap_statustostr(status));
+       }
+#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
+       if (jflag != -1) {
+               status = pcap_set_tstamp_type(pc, jflag);
+               if (status < 0)
+                       error("%s: Can't set time stamp type: %s",
+                             device, pcap_statustostr(status));
+       }
+#endif
+       status = pcap_activate(pc);
+       if (status < 0) {
+               /*
+                * pcap_activate() failed.
+                */
+               cp = pcap_geterr(pc);
+               if (status == PCAP_ERROR)
+                       error("%s", cp);
+               else if (status == PCAP_ERROR_NO_SUCH_DEVICE) {
+                       /*
+                        * 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);
+                       return (NULL);
+               } else if (status == PCAP_ERROR_PERM_DENIED && *cp != '\0')
+                       error("%s: %s\n(%s)", device,
+                           pcap_statustostr(status), cp);
+               else
+                       error("%s: %s", device,
+                           pcap_statustostr(status));
+       } else if (status > 0) {
+               /*
+                * pcap_activate() succeeded, but it's warning us
+                * of a problem it had.
+                */
+               cp = pcap_geterr(pc);
+               if (status == PCAP_WARNING)
+                       warning("%s", cp);
+               else if (status == PCAP_WARNING_PROMISC_NOTSUP &&
+                        *cp != '\0')
+                       warning("%s: %s\n(%s)", device,
+                           pcap_statustostr(status), cp);
+               else
+                       warning("%s: %s", device,
+                           pcap_statustostr(status));
+       }
+#ifdef HAVE_PCAP_SETDIRECTION
+       if (Qflag != -1) {
+               status = pcap_setdirection(pc, Qflag);
+               if (status != 0)
+                       error("%s: pcap_setdirection() failed: %s",
+                             device,  pcap_geterr(pc));
+               }
+#endif /* HAVE_PCAP_SETDIRECTION */
+#else /* HAVE_PCAP_CREATE */
+       *ebuf = '\0';
+       pc = pcap_open_live(device, ndo->ndo_snaplen, !pflag, 1000, ebuf);
+       if (pc == NULL) {
+               /*
+                * If this failed with "No such device", that means
+                * the interface doesn't exist; return NULL, so that
+                * the caller can see whether the device name is
+                * actually an interface index.
+                */
+               if (strstr(ebuf, "No such device") != NULL)
+                       return (NULL);
+               error("%s", ebuf);
+       }
+       if (*ebuf)
+               warning("%s", ebuf);
+#endif /* HAVE_PCAP_CREATE */
+
+       return (pc);
+}
+
 int
 main(int argc, char **argv)
 {
@@ -912,8 +1123,8 @@ main(int argc, char **argv)
        char *ret = NULL;
        char *end;
 #ifdef HAVE_PCAP_FINDALLDEVS
-       pcap_if_t *dev, *devlist;
-       int devnum;
+       pcap_if_t *devlist;
+       long devnum;
 #endif
        int status;
        FILE *VFile;
@@ -921,16 +1132,12 @@ main(int argc, char **argv)
        cap_rights_t rights;
        int cansandbox;
 #endif /* HAVE_CAPSICUM */
-       int Bflag = 0;                  /* buffer size */
-       int jflag = -1;                 /* packet time stamp source */
        int Oflag = 1;                  /* run filter code optimizer */
-       int pflag = 0;                  /* don't go promiscuous */
        int yflag_dlt = -1;
        const char *yflag_dlt_name = NULL;
 
        netdissect_options Ndo;
        netdissect_options *ndo = &Ndo;
-       int immediate_mode = 0;
 
        /*
         * Initialize the netdissect code.
@@ -1062,42 +1269,6 @@ main(int argc, char **argv)
                        break;
 
                case 'i':
-                       if (optarg[0] == '0' && optarg[1] == 0)
-                               error("Invalid adapter index");
-
-#ifdef HAVE_PCAP_FINDALLDEVS
-                       /*
-                        * If the argument is a number, treat it as
-                        * an index into the list of adapters, as
-                        * printed by "tcpdump -D".
-                        *
-                        * This should be OK on UNIX systems, as interfaces
-                        * shouldn't have names that begin with digits.
-                        * It can be useful on Windows, where more than
-                        * one interface can have the same name.
-                        */
-                       devnum = strtol(optarg, &end, 10);
-                       if (optarg != end && *end == '\0') {
-                               if (devnum < 0)
-                                       error("Invalid adapter index");
-
-                               if (pcap_findalldevs(&devlist, ebuf) < 0)
-                                       error("%s", ebuf);
-                               /*
-                                * Look for the devnum-th entry in the
-                                * list of devices (1-based).
-                                */
-                               for (i = 0, dev = devlist;
-                                   i < devnum-1 && dev != NULL;
-                                   i++, dev = dev->next)
-                                       ;
-                               if (dev == NULL)
-                                       error("Invalid adapter index");
-                               device = strdup(dev->name);
-                               pcap_freealldevs(devlist);
-                               break;
-                       }
-#endif /* HAVE_PCAP_FINDALLDEVS */
                        device = optarg;
                        break;
 
@@ -1477,148 +1648,73 @@ main(int argc, char **argv)
                 * We're doing a live capture.
                 */
                if (device == NULL) {
+                       /*
+                        * No interface was specified.  Pick one.
+                        */
 #ifdef HAVE_PCAP_FINDALLDEVS
+                       /*
+                        * Find the list of interfaces, and pick
+                        * the first interface.
+                        */
                        if (pcap_findalldevs(&devlist, ebuf) >= 0 &&
                            devlist != NULL) {
                                device = strdup(devlist->name);
                                pcap_freealldevs(devlist);
                        }
 #else /* HAVE_PCAP_FINDALLDEVS */
+                       /*
+                        * Use whatever interface pcap_lookupdev()
+                        * chooses.
+                        */
                        device = pcap_lookupdev(ebuf);
 #endif
                        if (device == NULL)
                                error("%s", ebuf);
                }
-#ifdef _WIN32
-               /*
-                * Print a message to the standard error on Windows.
-                * XXX - why do it here, with a different message?
-                */
-               if(strlen(device) == 1) /* we assume that an ASCII string is always longer than 1 char */
-               {                                               /* a Unicode string has a \0 as second byte (so strlen() is 1) */
-                       fprintf(stderr, "%s: listening on %ws\n", program_name, device);
-               }
-               else
-               {
-                       fprintf(stderr, "%s: listening on %s\n", program_name, device);
-               }
-
-               fflush(stderr);
-#endif /* _WIN32 */
-#ifdef HAVE_PCAP_CREATE
-               pd = pcap_create(device, ebuf);
-               if (pd == NULL)
-                       error("%s", ebuf);
-#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
-               if (Jflag)
-                       show_tstamp_types_and_exit(device);
-#endif
-#ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
-               status = pcap_set_tstamp_precision(pd, ndo->ndo_tstamp_precision);
-               if (status != 0)
-                       error("%s: Can't set %ssecond time stamp precision: %s",
-                               device,
-                               tstamp_precision_to_string(ndo->ndo_tstamp_precision),
-                               pcap_statustostr(status));
-#endif
 
-#ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
-               if (immediate_mode) {
-                       status = pcap_set_immediate_mode(pd, 1);
-                       if (status != 0)
-                               error("%s: Can't set immediate mode: %s",
-                               device,
-                               pcap_statustostr(status));
-               }
-#endif
                /*
-                * Is this an interface that supports monitor mode?
+                * Try to open the interface with the specified name.
                 */
-               if (pcap_can_set_rfmon(pd) == 1)
-                       supports_monitor_mode = 1;
-               else
-                       supports_monitor_mode = 0;
-               status = pcap_set_snaplen(pd, ndo->ndo_snaplen);
-               if (status != 0)
-                       error("%s: Can't set snapshot length: %s",
-                           device, pcap_statustostr(status));
-               status = pcap_set_promisc(pd, !pflag);
-               if (status != 0)
-                       error("%s: Can't set promiscuous mode: %s",
-                           device, pcap_statustostr(status));
-               if (Iflag) {
-                       status = pcap_set_rfmon(pd, 1);
-                       if (status != 0)
-                               error("%s: Can't set monitor mode: %s",
-                                   device, pcap_statustostr(status));
-               }
-               status = pcap_set_timeout(pd, 1000);
-               if (status != 0)
-                       error("%s: pcap_set_timeout failed: %s",
-                           device, pcap_statustostr(status));
-               if (Bflag != 0) {
-                       status = pcap_set_buffer_size(pd, Bflag);
-                       if (status != 0)
-                               error("%s: Can't set buffer size: %s",
-                                   device, pcap_statustostr(status));
-               }
-#ifdef HAVE_PCAP_SET_TSTAMP_TYPE
-                if (jflag != -1) {
-                       status = pcap_set_tstamp_type(pd, jflag);
-                       if (status < 0)
-                               error("%s: Can't set time stamp type: %s",
-                                     device, pcap_statustostr(status));
-               }
-#endif
-               status = pcap_activate(pd);
-               if (status < 0) {
+               pd = open_interface(device, ndo, ebuf);
+               if (pd == NULL) {
                        /*
-                        * pcap_activate() failed.
+                        * That failed.  If we can get a list of
+                        * interfaces, and the interface name
+                        * is purely numeric, try to use it as
+                        * a 1-based index in the list of
+                        * interfaces.
                         */
-                       cp = pcap_geterr(pd);
-                       if (status == PCAP_ERROR)
-                               error("%s", cp);
-                       else if ((status == PCAP_ERROR_NO_SUCH_DEVICE ||
-                                 status == PCAP_ERROR_PERM_DENIED) &&
-                                *cp != '\0')
-                               error("%s: %s\n(%s)", device,
-                                   pcap_statustostr(status), cp);
-                       else
-                               error("%s: %s", device,
-                                   pcap_statustostr(status));
-               } else if (status > 0) {
+#ifdef HAVE_PCAP_FINDALLDEVS
+                       devnum = parse_interface_number(device);
+                       if (devnum == -1) {
+                               /*
+                                * It's not a number; just report
+                                * the open error and fail.
+                                */
+                               error("%s", ebuf);
+                       }
+
                        /*
-                        * pcap_activate() succeeded, but it's warning us
-                        * of a problem it had.
+                        * OK, it's a number; try to find the
+                        * interface with that index, and try
+                        * to open it.
+                        *
+                        * find_interface_by_number() exits if it
+                        * couldn't be found.
+                        */
+                       device = find_interface_by_number(devnum);
+                       pd = open_interface(device, ndo, ebuf);
+                       if (pd == NULL)
+                               error("%s", ebuf);
+#else /* HAVE_PCAP_FINDALLDEVS */
+                       /*
+                        * We can't get a list of interfaces; just
+                        * fail.
                         */
-                       cp = pcap_geterr(pd);
-                       if (status == PCAP_WARNING)
-                               warning("%s", cp);
-                       else if (status == PCAP_WARNING_PROMISC_NOTSUP &&
-                                *cp != '\0')
-                               warning("%s: %s\n(%s)", device,
-                                   pcap_statustostr(status), cp);
-                       else
-                               warning("%s: %s", device,
-                                   pcap_statustostr(status));
-               }
-#ifdef HAVE_PCAP_SETDIRECTION
-               if (Qflag != -1) {
-                       status = pcap_setdirection(pd, Qflag);
-                       if (status != 0)
-                               error("%s: pcap_setdirection() failed: %s",
-                                     device,  pcap_geterr(pd));
-               }
-#endif /* HAVE_PCAP_SETDIRECTION */
-#else
-               *ebuf = '\0';
-               pd = pcap_open_live(device, ndo->ndo_snaplen, !pflag, 1000,
-                   ebuf);
-               if (pd == NULL)
                        error("%s", ebuf);
-               else if (*ebuf)
-                       warning("%s", ebuf);
-#endif /* HAVE_PCAP_CREATE */
+#endif /* HAVE_PCAP_FINDALLDEVS */
+               }
+
                /*
                 * Let user own process after socket has been opened.
                 */
@@ -1633,7 +1729,7 @@ main(int argc, char **argv)
                        }
 #endif /* !defined(HAVE_PCAP_CREATE) && defined(_WIN32) */
                if (Lflag)
-                       show_dlts_and_exit(device);
+                       show_dlts_and_exit(pd, device);
                if (yflag_dlt >= 0) {
 #ifdef HAVE_PCAP_SET_DATALINK
                        if (pcap_set_datalink(pd, yflag_dlt) < 0)
@@ -1865,7 +1961,6 @@ main(int argc, char **argv)
 #endif
        }
 
-#ifndef _WIN32
        if (RFileName == NULL) {
                /*
                 * Live capture (if -V was specified, we set RFileName
@@ -1890,7 +1985,6 @@ main(int argc, char **argv)
                }
                (void)fflush(stderr);
        }
-#endif /* _WIN32 */
 
 #ifdef HAVE_CAPSICUM
        cansandbox = (ndo->ndo_nflag && VFileName == NULL && zflag == NULL);