fix build on openbsd

diff --git a/src/protocols/arp.h b/src/protocols/arp.h
index 8da8989ae71b8c8fa88e754e9ab13b19dd8e1107..533eb759b7d43ae92f9e19868f53241cd4984510 100644 (file)
--- a/src/protocols/arp.h
+++ b/src/protocols/arp.h
@@ -47,10 +47,21 @@ struct EtherARP
 constexpr uint16_t ETHERARP_HDR_LEN = 28; /*  sizeof EtherARP != 28 */
 } // namespace arp
 
+#ifndef ARPOP_REQUEST
 constexpr uint16_t ARPOP_REQUEST = 1;  /* ARP request  */
+#endif
+
+#ifndef ARPOP_REPLY
 constexpr uint16_t ARPOP_REPLY = 2;    /* ARP reply    */
+#endif
+
+#ifndef ARPOP_RREQUEST
 constexpr uint16_t ARPOP_RREQUEST = 3; /* RARP request */
+#endif
+
+#ifndef ARPOP_RREPLY
 constexpr uint16_t ARPOP_RREPLY = 4;   /* RARP reply   */
+#endif
 
 #endif