Merge pull request #880 from Oppen/linux-simplify_dev_detection

Linux: remove procfs and sysfs crawling for interface detection.

1 files changed, 1 insertions, 254 deletions

diff --git a/pcap-linux.c b/pcap-linux.c
index 004bc91b..444d509c 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -2284,220 +2284,6 @@ add_linux_if(pcap_if_list_t *devlistp, const char *ifname, int fd, char *errbuf)
 }
 
 /*
- * Get from "/sys/class/net" 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 "/sys/class/net"; we just leave
- * the list of interfaces as is, and return 0, so that we can try
- * scanning /proc/net/dev.
- *
- * Otherwise, we return 1 if we don't get an error and -1 if we do.
- */
-static int
-scan_sys_class_net(pcap_if_list_t *devlistp, char *errbuf)
-{
-	DIR *sys_class_net_d;
-	int fd;
-	struct dirent *ent;
-	char subsystem_path[PATH_MAX+1];
-	struct stat statb;
-	int ret = 1;
-
-	sys_class_net_d = opendir("/sys/class/net");
-	if (sys_class_net_d == NULL) {
-		/*
-		 * Don't fail if it doesn't exist at all.
-		 */
-		if (errno == ENOENT)
-			return (0);
-
-		/*
-		 * Fail if we got some other error.
-		 */
-		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
-		    errno, "Can't open /sys/class/net");
-		return (-1);
-	}
-
-	/*
-	 * Create a socket from which to fetch interface information.
-	 */
-	fd = socket(PF_UNIX, SOCK_RAW, 0);
-	if (fd < 0) {
-		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
-		    errno, "socket");
-		(void)closedir(sys_class_net_d);
-		return (-1);
-	}
-
-	for (;;) {
-		errno = 0;
-		ent = readdir(sys_class_net_d);
-		if (ent == NULL) {
-			/*
-			 * Error or EOF; if errno != 0, it's an error.
-			 */
-			break;
-		}
-
-		/*
-		 * Ignore "." and "..".
-		 */
-		if (strcmp(ent->d_name, ".") == 0 ||
-		    strcmp(ent->d_name, "..") == 0)
-			continue;
-
-		/*
-		 * Ignore plain files; they do not have subdirectories
-		 * and thus have no attributes.
-		 */
-		if (ent->d_type == DT_REG)
-			continue;
-
-		/*
-		 * Is there an "ifindex" file under that name?
-		 * (We don't care whether it's a directory or
-		 * a symlink; older kernels have directories
-		 * for devices, newer kernels have symlinks to
-		 * directories.)
-		 */
-		snprintf(subsystem_path, sizeof subsystem_path,
-		    "/sys/class/net/%s/ifindex", ent->d_name);
-		if (lstat(subsystem_path, &statb) != 0) {
-			/*
-			 * Stat failed.  Either there was an error
-			 * other than ENOENT, and we don't know if
-			 * this is an interface, or it's ENOENT,
-			 * and either some part of "/sys/class/net/{if_name}"
-			 * disappeared, in which case it probably means
-			 * the interface disappeared, or there's no
-			 * "ifindex" file, which means it's not a
-			 * network interface.
-			 */
-			continue;
-		}
-
-		/*
-		 * Attempt to add the interface.
-		 */
-		if (add_linux_if(devlistp, &ent->d_name[0], fd, errbuf) == -1) {
-			/* Fail. */
-			ret = -1;
-			break;
-		}
-	}
-	if (ret != -1) {
-		/*
-		 * Well, we didn't fail for any other reason; did we
-		 * fail due to an error reading the directory?
-		 */
-		if (errno != 0) {
-			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
-			    errno, "Error reading /sys/class/net");
-			ret = -1;
-		}
-	}
-
-	(void)close(fd);
-	(void)closedir(sys_class_net_d);
-	return (ret);
-}
-
-/*
- * 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.
- *
- * See comments from scan_sys_class_net().
- */
-static int
-scan_proc_net_dev(pcap_if_list_t *devlistp, char *errbuf)
-{
-	FILE *proc_net_f;
-	int fd;
-	char linebuf[512];
-	int linenum;
-	char *p;
-	int ret = 0;
-
-	proc_net_f = fopen("/proc/net/dev", "r");
-	if (proc_net_f == NULL) {
-		/*
-		 * Don't fail if it doesn't exist at all.
-		 */
-		if (errno == ENOENT)
-			return (0);
-
-		/*
-		 * Fail if we got some other error.
-		 */
-		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
-		    errno, "Can't open /proc/net/dev");
-		return (-1);
-	}
-
-	/*
-	 * Create a socket from which to fetch interface information.
-	 */
-	fd = socket(PF_UNIX, SOCK_RAW, 0);
-	if (fd < 0) {
-		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
-		    errno, "socket");
-		(void)fclose(proc_net_f);
-		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 == ' ' || *p == '\t')
-			p++;
-		if (*p == '\0' || *p == '\n')
-			continue;	/* blank line */
-
-		/*
-		 * Attempt to add the interface.
-		 */
-		if (add_linux_if(devlistp, p, fd, errbuf) == -1) {
-			/* Fail. */
-			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)) {
-			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
-			    errno, "Error reading /proc/net/dev");
-			ret = -1;
-		}
-	}
-
-	(void)close(fd);
-	(void)fclose(proc_net_f);
-	return (ret);
-}
-
-/*
  * Description string for the "any" device.
  */
 static const char any_descr[] = "Pseudo-device that captures on all interfaces";
@@ -2685,46 +2471,7 @@ get_if_flags(const char *name, bpf_u_int32 *flags, char *errbuf)
 int
 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
 {
-	int ret;
-
-	/*
-	 * Get the list of regular interfaces first.
-	 */
-	if (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
-	    get_if_flags) == -1)
-		return (-1);	/* failure */
-
-	/*
-	 * Read "/sys/class/net", 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 "/sys/class/net"
-	 * to get the names of the rest of the interfaces.
-	 */
-	ret = scan_sys_class_net(devlistp, errbuf);
-	if (ret == -1)
-		return (-1);	/* failed */
-	if (ret == 0) {
-		/*
-		 * No /sys/class/net; try reading /proc/net/dev instead.
-		 */
-		if (scan_proc_net_dev(devlistp, errbuf) == -1)
-			return (-1);
-	}
-
-	/*
-	 * Add the "any" device.
-	 * As it refers to all network devices, not to any particular
-	 * network device, the notion of "connected" vs. "disconnected"
-	 * doesn't apply.
-	 */
-	if (add_dev(devlistp, "any",
-	    PCAP_IF_UP|PCAP_IF_RUNNING|PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
-	    any_descr, errbuf) == NULL)
-		return (-1);
-
-	return (0);
+	return pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound, get_if_flags);
 }
 
 /*