List only ethernet interfaces

diff --git a/ethsock.c b/ethsock.c
index 56f554904cd726f8acff10f1740d68c70d7b2b34..b96c289ea1e7cad37a98ccd0f97603917995418c 100644 (file)
--- a/ethsock.c
+++ b/ethsock.c
@@ -76,10 +76,6 @@ static bool get_hwaddr(uint8_t *hwaddr, const char *interface)
                }
        }
 
-       if (!found) {
-               fprintf(stderr, "Failed to get MAC address of interface %s.\n", interface);
-       }
-
        freeifaddrs(ifas);
        return found;
 }
@@ -109,12 +105,14 @@ static bool get_hwaddr(uint8_t *hwaddr, const char *interface)
                        }
 
                        if (!strcmp(adapter->AdapterName, interface)) {
-                               for (i = 0; i != MIN(adapter->AddressLength, 6); ++i) {
-                                       hwaddr[i] = adapter->Address[i];
-                               }
+                               if (adapter->AddressLength == 6) {
+                                       for (i = 0; i != 6; ++i) {
+                                               hwaddr[i] = adapter->Address[i];
+                                       }
 
-                               found = true;
-                               break;
+                                       found = true;
+                                       break;
+                               }
                        }
                }
        } else {
@@ -145,10 +143,6 @@ struct ethsock *ethsock_create(const char *interface, uint16_t protocol)
                return NULL;
        }
 
-       if (!get_hwaddr(sock->hwaddr, interface)) {
-               goto cleanup_malloc;
-       }
-
        buf[0] = '\0';
 
        sock->pcap = pcap_open_live(interface, BUFSIZ, 1, 1, buf);
@@ -162,10 +156,16 @@ struct ethsock *ethsock_create(const char *interface, uint16_t protocol)
        }
 
        if (pcap_datalink(sock->pcap) != DLT_EN10MB) {
-               fprintf(stderr, "Interface %s not supported.\n", interface);
+               fprintf(stderr, "Interface %s is not an ethernet interface.\n",
+                               interface);
                goto cleanup_pcap;
        }
 
+       if (!get_hwaddr(sock->hwaddr, interface)) {
+               fprintf(stderr, "Failed to get MAC address of interface.\n");
+               goto cleanup_malloc;
+       }
+
        sock->fd = pcap_get_selectable_fd(sock->pcap);
        if (sock->fd == -1) {
                fprintf(stderr, "No selectable file descriptor available.\n");
@@ -262,10 +262,26 @@ int ethsock_set_timeout(struct ethsock *sock, unsigned msec)
        return 0;
 }
 
+static bool is_ethernet(const char *interface)
+{
+       pcap_t *pcap;
+       char errbuf[PCAP_ERRBUF_SIZE];
+       bool ret = false;
+
+       if ((pcap = pcap_create(interface, errbuf))) {
+               if (pcap_activate(pcap) == 0) {
+                       ret = (pcap_datalink(pcap) == DLT_EN10MB);
+               }
+               pcap_close(pcap);
+       }
+
+       return ret;
+}
+
 int ethsock_list_all(void)
 {
        pcap_if_t *devs, *dev;
-       uint8_t hwaddr[8];
+       uint8_t hwaddr[6];
        char errbuf[PCAP_ERRBUF_SIZE];
 
        if (pcap_findalldevs(&devs, errbuf) != 0) {
@@ -273,15 +289,26 @@ int ethsock_list_all(void)
                return -1;
        }
 
+       memset(hwaddr, 0, 6);
+
        for (dev = devs; dev; dev = dev->next) {
-               get_hwaddr(hwaddr, dev->name);
-               printf("%02x:%02x:%02x:%02x:%02x:%02x %s",
-                               hwaddr[0], hwaddr[1], hwaddr[2],
-                               hwaddr[3], hwaddr[4], hwaddr[5],
-                               dev->name);
+               if (dev->flags & PCAP_IF_LOOPBACK) {
+                       continue;
+               }
+
+               if (!is_ethernet(dev->name)) {
+                       continue;
+               }
+
+               if (!get_hwaddr(hwaddr, dev->name)) {
+                       continue;
+               }
+
+               printf("%s  %02x:%02x:%02x:%02x:%02x:%02x", dev->name, hwaddr[0],
+                               hwaddr[1], hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
 
                if (dev->description) {
-                       printf(" (%s)\n", dev->description);
+                       printf("    (%s)\n", dev->description);
                } else {
                        printf("\n");
                }