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 91d86d948795b4a156747a556cc4cef2d7101f04..4464a996a6113ea31126f4fea11bcb2ecd944b6e 100644 (file)
--- a/src/eui/Eui48.cc
+++ b/src/eui/Eui48.cc
@@ -174,6 +174,11 @@ 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
@@ -313,6 +318,11 @@ 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;