Get interface names using ioctl rather than /proc, from Nick Fedchik

diff --git a/networking/nameif.c b/networking/nameif.c
index 4b2d090..a9d4221 100644 (file)
--- a/networking/nameif.c
+++ b/networking/nameif.c
@@ -22,21 +22,20 @@
  *
  */
 
+
 #include <sys/syslog.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
-
 #include <errno.h>
 #include <getopt.h>
 #include <stdlib.h>
 #include <string.h>
 #include <net/if.h>
 #include <netinet/ether.h>
+#include <linux/sockios.h>
 
 #include "busybox.h"
 
-/* set interface name, from <linux/sockios.h> */
-#define SIOCSIFNAME    0x8923
 /* Octets in one ethernet addr, from <linux/if_ether.h>         */
 #define ETH_ALEN       6
 
@@ -46,12 +45,12 @@
 
 typedef struct mactable_s {
        struct mactable_s *next;
-       struct mactable_s **pprev;
+       struct mactable_s *prev;
        char *ifname;
        struct ether_addr *mac;
 } mactable_t;
 
-static void serror_msg_and_die(const char use_syslog, const char *s, ...)
+static void serror(const char use_syslog, const char *s, ...)
 {
        va_list ap;
 
@@ -67,20 +66,35 @@ static void serror_msg_and_die(const char use_syslog, const char *s, ...)
        }
 
        va_end(ap);
-       
+
        exit(EXIT_FAILURE);
 }
 
+/* Check ascii str_macaddr, convert and copy to *mac */
+struct ether_addr *cc_macaddr(char *str_macaddr, unsigned char use_syslog)
+{
+       struct ether_addr *lmac, *mac;
+
+       lmac = ether_aton(str_macaddr);
+       if (lmac == NULL)
+               serror(use_syslog, "cannot parse MAC %s", str_macaddr);
+       mac = xcalloc(1, ETH_ALEN);
+       memcpy(mac, lmac, ETH_ALEN);
+
+       return mac;
+}
+
 int nameif_main(int argc, char **argv)
 {
        mactable_t *clist = NULL;
        FILE *ifh;
        char *fname = "/etc/mactab";
        char *line;
-       unsigned short linenum = 0;
        unsigned char use_syslog = 0;
        int ctl_sk = -1;
        int opt;
+       int if_index = 1;
+       mactable_t *ch = NULL;
 
        static struct option opts[] = {
                {"syslog", 0, NULL, 's'},
@@ -101,40 +115,33 @@ int nameif_main(int argc, char **argv)
                }
        }
 
-       if ((argc - optind) & 1) {
+       if ((argc - optind) & 1)
                show_usage();
-       }
 
        if (optind < argc) {
                while (optind < argc) {
-                       struct ether_addr *mac;
-                       mactable_t *ch;
 
-                       if (strlen(argv[optind]) > IF_NAMESIZE) {
-                               serror_msg_and_die(use_syslog, "interface name `%s' too long", argv[optind]);
-                       }
+                       if (strlen(argv[optind]) > IF_NAMESIZE)
+                               serror(use_syslog, "interface name `%s' too long",
+                                          argv[optind]);
                        optind++;
-                       mac = ether_aton(argv[optind]);
-                       if (mac == NULL) {
-                               serror_msg_and_die(use_syslog, "cannot parse MAC %s", argv[optind]);
-                       }
+
                        ch = xcalloc(1, sizeof(mactable_t));
+                       ch->next = NULL;
+                       ch->prev = NULL;
                        ch->ifname = strdup(argv[optind - 1]);
-                       ch->mac = xcalloc(1, ETH_ALEN);
-                       memcpy(ch->mac, mac, ETH_ALEN);
+                       ch->mac = cc_macaddr(argv[optind], use_syslog);
                        optind++;
                        if (clist)
-                               clist->pprev = &ch->next;
+                               clist->prev = ch->next;
                        ch->next = clist;
-                       ch->pprev = &clist;
+                       ch->prev = clist;
                        clist = ch;
                }
        } else {
                ifh = xfopen(fname, "r");
 
                while ((line = get_line_from_file(ifh)) != NULL) {
-                       struct ether_addr *mac;
-                       mactable_t *ch;
                        char *line_ptr;
                        unsigned short name_length;
 
@@ -142,74 +149,71 @@ int nameif_main(int argc, char **argv)
                        if ((line_ptr[0] == '#') || (line_ptr[0] == '\n'))
                                continue;
                        name_length = strcspn(line_ptr, " \t");
-                       if (name_length > IF_NAMESIZE) {
-                               serror_msg_and_die(use_syslog, "interface name `%s' too long", argv[optind]); 
-                       }
+                       if (name_length > IF_NAMESIZE)
+                               serror(use_syslog, "interface name `%s' too long",
+                                          argv[optind]);
                        ch = xcalloc(1, sizeof(mactable_t));
+                       ch->next = NULL;
+                       ch->prev = NULL;
                        ch->ifname = strndup(line_ptr, name_length);
                        line_ptr += name_length;
                        line_ptr += strspn(line_ptr, " \t");
                        name_length = strspn(line_ptr, "0123456789ABCDEFabcdef:");
                        line_ptr[name_length] = '\0';
-                       mac = ether_aton(line_ptr);
-                       if (mac == NULL) {
-                               serror_msg_and_die(use_syslog,  "cannot parse MAC %s", argv[optind]);
-                       }
-                       ch->mac = xcalloc(1, ETH_ALEN);
-                       memcpy(ch->mac, mac, ETH_ALEN);
+                       ch->mac = cc_macaddr(line_ptr, use_syslog);
                        if (clist)
-                               clist->pprev = &ch->next;
+                               clist->prev = ch;
                        ch->next = clist;
-                       ch->pprev = &clist;
                        clist = ch;
                        free(line);
                }
                fclose(ifh);
        }
 
-       ifh = xfopen("/proc/net/dev", "r");
-       while ((line = get_line_from_file(ifh)) != NULL) {
-               char *line_ptr;
-               unsigned short iface_name_length;
+       if ((ctl_sk = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
+               serror(use_syslog, "socket: %s", strerror(errno));
+
+       while (clist) {
                struct ifreq ifr;
-               mactable_t *ch = NULL;
 
-               linenum++;
-               if (linenum < 3)
-                       continue;
-               line_ptr = line + strspn(line, " \t");
-               if (line_ptr[0] == '\n')
-                       continue;
-               iface_name_length = strcspn(line_ptr, ":");
-               if (ctl_sk < 0)
-                       ctl_sk = socket(PF_INET, SOCK_DGRAM, 0);
-               memset(&ifr, 0, sizeof(struct ifreq));
-               strncpy(ifr.ifr_name, line_ptr, iface_name_length);
-               if (ioctl(ctl_sk, SIOCGIFHWADDR, &ifr) < 0) {
-//                     serror_msg(use_syslog, "cannot read hardware address of %s: %s", ifr.ifr_name, strerror(errno));
+               bzero(&ifr, sizeof(struct ifreq));
+               if_index++;
+               ifr.ifr_ifindex = if_index;
+
+               /* Get ifname by index or die */
+               if (ioctl(ctl_sk, SIOCGIFNAME, &ifr))
+                       break;
+
+               /* Has this device hwaddr? */
+               if (ioctl(ctl_sk, SIOCGIFHWADDR, &ifr))
                        continue;
-               }
+
+               /* Search for mac like in ifr.ifr_hwaddr.sa_data */
                for (ch = clist; ch; ch = ch->next)
                        if (!memcmp(ch->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN))
                                break;
-               if (ch == NULL) {
+
+               /* Nothing found for current ifr.ifr_hwaddr.sa_data */
+               if (ch == NULL)
                        continue;
-               }
 
                strcpy(ifr.ifr_newname, ch->ifname);
-
-               if (ioctl(ctl_sk, SIOCSIFNAME, &ifr) < 0) {;
-                       serror_msg_and_die(use_syslog, "cannot change name of %s to %s: %s", ifr.ifr_name, ch->ifname, strerror(errno));
+               if (ioctl(ctl_sk, SIOCSIFNAME, &ifr) < 0)
+                       serror(use_syslog, "cannot change ifname %s to %s: %s",
+                                  ifr.ifr_name, ch->ifname, strerror(errno));
+
+               /* Remove list entry of renamed interface */
+               if (ch->prev != NULL) {
+                       (ch->prev)->next = ch->next;
+               } else {
+                       clist = ch->next;
                }
-               *ch->pprev = ch->next;
+               if (ch->next != NULL)
+                       (ch->next)->prev = ch->prev;
                free(ch);
-               free(line);
        }
-       fclose(ifh);
 
        while (clist) {
-               mactable_t *ch;
-
                ch = clist;
                clist = clist->next;
                free(ch);