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 a96561a74961cde33d199324ba29f19b85ddda46..c151feb6d64a6f0f12c3741a42d31f5fe9eafdcc 100644 (file)
--- a/src/eui/Eui48.cc
+++ b/src/eui/Eui48.cc
@@ -173,6 +173,11 @@ 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
@@ -312,6 +317,11 @@ 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;