libeui: Warn and fail nicely on socket errors looking up ARP record

If something nasty happened (out of FD or similar) socket() may fail.
Report these events and continue with unknown EUI value.

 Detected by Coverity Scan. Issue 740393

diff --git a/src/eui/Eui48.cc b/src/eui/Eui48.cc
index 57694d8192c4976eab415008fda81e2e705a715d..0ad019471a2d86ad38a6dfb382b62a09a0a77019 100644 (file)
--- a/src/eui/Eui48.cc
+++ b/src/eui/Eui48.cc
@@ -176,6 +176,11 @@ Eui::Eui48::lookup(const Ip::Address &c)
 
     /* IPv6 builds do not provide the first http_port as an IPv4 socket for ARP */
     int tmpSocket = socket(AF_INET,SOCK_STREAM,0);
+    if (tmpSocket < 0) {
+        debugs(28, DBG_IMPORTANT, "Attempt to open socket for EUI retrieval failed: " << xstrerror());
+        clear();
+        return false;
+    }
 
     /*
      * The linux kernel 2.2 maintains per interface ARP caches and
@@ -315,6 +320,11 @@ Eui::Eui48::lookup(const Ip::Address &c)
 
     /* IPv6 builds do not provide the first http_port as an IPv4 socket for ARP */
     int tmpSocket = socket(AF_INET,SOCK_STREAM,0);
+    if (tmpSocket < 0) {
+        debugs(28, DBG_IMPORTANT, "Attempt to open socket for EUI retrieval failed: " << xstrerror());
+        clear();
+        return false;
+    }
 
     /* Set up structures for ARP lookup with blank interface name */
     struct arpreq arpReq;