aboutsummaryrefslogtreecommitdiffstats
path: root/pcap-linux.c
diff options
context:
space:
mode:
authorGuy Harris <guy@alum.mit.edu>2010-01-09 18:46:02 -0800
committerGuy Harris <guy@alum.mit.edu>2010-01-09 18:46:02 -0800
commit6831a814896d7f1c31bfa68af85028e8d4182543 (patch)
tree137c36f3e0e4ec572d9139ba5c1cabd03f5a6696 /pcap-linux.c
parentfc03e2cbb69f94efdda0ee05206ad9336b35844f (diff)
Scan /proc/net/dev on Linux regardless of how we get the interface list.
It's a Linuxism, so it's not necessary on other platforms, and is useful even if we have getifaddrs().
Diffstat (limited to 'pcap-linux.c')
-rw-r--r--pcap-linux.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/pcap-linux.c b/pcap-linux.c
index 22339d6..08bd910 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -1774,6 +1774,148 @@ pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats)
return 0;
}
+#ifdef HAVE_PROC_NET_DEV
+/*
+ * Get from "/proc/net/dev" all interfaces listed there; if they're
+ * already in the list of interfaces we have, that won't add another
+ * instance, but if they're not, that'll add them.
+ *
+ * We don't bother getting any addresses for them; it appears you can't
+ * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and,
+ * although some other types of addresses can be fetched with SIOCGIFADDR,
+ * we don't bother with them for now.
+ *
+ * We also don't fail if we couldn't open "/proc/net/dev"; we just leave
+ * the list of interfaces as is.
+ */
+static int
+scan_proc_net_dev(pcap_if_t **devlistp, char *errbuf)
+{
+ FILE *proc_net_f;
+ int fd;
+ char linebuf[512];
+ int linenum;
+ unsigned char *p;
+ char name[512]; /* XXX - pick a size */
+ char *q, *saveq;
+ struct ifreq ifrflags;
+ int ret = 0;
+
+ proc_net_f = fopen("/proc/net/dev", "r");
+ if (proc_net_f == NULL)
+ return (0);
+
+ /*
+ * Create a socket from which to fetch interface information.
+ */
+ fd = socket(AF_INET, SOCK_DGRAM, 0);
+ if (fd < 0) {
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "socket: %s", pcap_strerror(errno));
+ return (-1);
+ }
+
+ for (linenum = 1;
+ fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) {
+ /*
+ * Skip the first two lines - they're headers.
+ */
+ if (linenum <= 2)
+ continue;
+
+ p = &linebuf[0];
+
+ /*
+ * Skip leading white space.
+ */
+ while (*p != '\0' && isspace(*p))
+ p++;
+ if (*p == '\0' || *p == '\n')
+ continue; /* blank line */
+
+ /*
+ * Get the interface name.
+ */
+ q = &name[0];
+ while (*p != '\0' && !isspace(*p)) {
+ if (*p == ':') {
+ /*
+ * This could be the separator between a
+ * name and an alias number, or it could be
+ * the separator between a name with no
+ * alias number and the next field.
+ *
+ * If there's a colon after digits, it
+ * separates the name and the alias number,
+ * otherwise it separates the name and the
+ * next field.
+ */
+ saveq = q;
+ while (isdigit(*p))
+ *q++ = *p++;
+ if (*p != ':') {
+ /*
+ * That was the next field,
+ * not the alias number.
+ */
+ q = saveq;
+ }
+ break;
+ } else
+ *q++ = *p++;
+ }
+ *q = '\0';
+
+ /*
+ * Get the flags for this interface, and skip it if
+ * it's not up.
+ */
+ strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name));
+ if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {
+ if (errno == ENXIO)
+ continue;
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "SIOCGIFFLAGS: %.*s: %s",
+ (int)sizeof(ifrflags.ifr_name),
+ ifrflags.ifr_name,
+ pcap_strerror(errno));
+ ret = -1;
+ break;
+ }
+ if (!(ifrflags.ifr_flags & IFF_UP))
+ continue;
+
+ /*
+ * Add an entry for this interface, with no addresses.
+ */
+ if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL,
+ errbuf) == -1) {
+ /*
+ * Failure.
+ */
+ ret = -1;
+ break;
+ }
+ }
+ if (ret != -1) {
+ /*
+ * Well, we didn't fail for any other reason; did we
+ * fail due to an error reading the file?
+ */
+ if (ferror(proc_net_f)) {
+ (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
+ "Error reading /proc/net/dev: %s",
+ pcap_strerror(errno));
+ ret = -1;
+ }
+ }
+
+ (void)close(fd);
+ (void)fclose(proc_net_f);
+ return (ret);
+}
+#endif /* HAVE_PROC_NET_DEV */
+
/*
* Description string for the "any" device.
*/
@@ -1782,25 +1924,53 @@ static const char any_descr[] = "Pseudo-device that captures on all interfaces";
int
pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
{
+#ifdef HAVE_PROC_NET_DEV
+ /*
+ * Read "/proc/net/dev", and add to the list of interfaces all
+ * interfaces listed there that we don't already have, because,
+ * on Linux, SIOCGIFCONF reports only interfaces with IPv4 addresses,
+ * and even getifaddrs() won't return information about
+ * interfaces with no addresses, so you need to read "/proc/net/dev"
+ * to get the names of the rest of the interfaces.
+ */
+ if (scan_proc_net_dev(alldevsp, errbuf) == -1)
+ return (-1);
+#endif
+
+ /*
+ * Add the "any" device.
+ */
if (pcap_add_if(alldevsp, "any", 0, any_descr, errbuf) < 0)
return (-1);
#ifdef HAVE_DAG_API
+ /*
+ * Add DAG devices.
+ */
if (dag_platform_finddevs(alldevsp, errbuf) < 0)
return (-1);
#endif /* HAVE_DAG_API */
#ifdef HAVE_SEPTEL_API
+ /*
+ * Add Septel devices.
+ */
if (septel_platform_finddevs(alldevsp, errbuf) < 0)
return (-1);
#endif /* HAVE_SEPTEL_API */
#ifdef PCAP_SUPPORT_BT
+ /*
+ * Add Bluetooth devices.
+ */
if (bt_platform_finddevs(alldevsp, errbuf) < 0)
return (-1);
#endif
#ifdef PCAP_SUPPORT_USB
+ /*
+ * Add USB devices.
+ */
if (usb_platform_finddevs(alldevsp, errbuf) < 0)
return (-1);
#endif