Unchecked ioctl Return Value

include/logger/logger.h

@@ -16,6 +16,10 @@
 #include <sys/socket.h>
 #include <arpa/inet.h>
 #include <netinet/in.h>
+#include <ifaddrs.h>
+#include <netpacket/packet.h>
+#include <cstring>
+#include <string>
 #include <errno.h>
 #include <stdlib.h>
 #include <sys/ioctl.h>

src/logger/logger.cpp

@@ -143,24 +143,44 @@ string Logger::getTimestamp()
  * \param	void
  * \return  string MAC address (formatted)
  */
-string Logger::getMacAddress()
+std::string Logger::getMacAddress()
 {
-    struct ifreq ifr;
-    int s = socket(AF_INET, SOCK_STREAM, 0);
+    struct ifaddrs *ifaddr, *ifa;
 
-    strcpy(ifr.ifr_name, "eth0");
-    if (ioctl(s, SIOCGIFHWADDR, &ifr) < 0)
+    // default MAC if none found
+    std::string result = "00:00:00:00:00:00";
+
+    if (getifaddrs(&ifaddr) == -1)
+        return result;
+
+    for (ifa = ifaddr; ifa != nullptr; ifa = ifa->ifa_next)
     {
-        strcpy(ifr.ifr_name, "eno1");
+        if (!ifa->ifa_addr)
+            continue;
+
+        // We want AF_PACKET interfaces (Ethernet)
+        if (ifa->ifa_addr->sa_family == AF_PACKET &&
+            !(ifa->ifa_flags & IFF_LOOPBACK) && // skip loopback interface
+            (ifa->ifa_flags & IFF_UP))          // must be up
+        {
+            struct sockaddr_ll *s = (struct sockaddr_ll *)ifa->ifa_addr;
+
+            if (s->sll_halen == 6)
+            {
+                char buf[32];
+                snprintf(buf, sizeof(buf),
+                         "%02X:%02X:%02X:%02X:%02X:%02X",
+                         s->sll_addr[0], s->sll_addr[1], s->sll_addr[2],
+                         s->sll_addr[3], s->sll_addr[4], s->sll_addr[5]);
+
+                freeifaddrs(ifaddr);
+                return std::string(buf);
+            }
+        }
     }
 
-    unsigned char *hwaddr = (unsigned char *)ifr.ifr_hwaddr.sa_data;
-    char buffer[80];
-    snprintf(buffer, sizeof(buffer), "%02X:%02X:%02X:%02X:%02X:%02X", hwaddr[0], hwaddr[1], hwaddr[2],
-             hwaddr[3], hwaddr[4], hwaddr[5]);
-    close(s);
-    string tmp = buffer;
-    return tmp;
+    freeifaddrs(ifaddr);
+    return result;
 }
 
 /**