Index: head/sys/dev/hyperv/netvsc/hv_net_vsc.h
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_net_vsc.h
+++ head/sys/dev/hyperv/netvsc/hv_net_vsc.h
@@ -275,6 +275,11 @@
 #define HN_CAP_TSO6			0x0100
 #define HN_CAP_HASHVAL			0x0200
 
+/* Capability description for use with printf(9) %b identifier. */
+#define HN_CAP_BITS				\
+	"\020\1VLAN\2MTU\3IPCS\4TCP4CS\5TCP6CS"	\
+	"\6UDP4CS\7UDP6CS\10TSO4\11TSO6\12HASHVAL"
+
 #define HN_LINK_FLAG_LINKUP		0x0001
 #define HN_LINK_FLAG_NETCHG		0x0002
 
Index: head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
===================================================================
--- head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
+++ head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c
@@ -2379,18 +2379,7 @@
 	HN_LOCK(sc);
 	caps = sc->hn_caps;
 	HN_UNLOCK(sc);
-	snprintf(caps_str, sizeof(caps_str), "%b", caps,
-	    "\020"
-	    "\001VLAN"
-	    "\002MTU"
-	    "\003IPCS"
-	    "\004TCP4CS"
-	    "\005TCP6CS"
-	    "\006UDP4CS"
-	    "\007UDP6CS"
-	    "\010TSO4"
-	    "\011TSO6"
-	    "\012HASHVAL");
+	snprintf(caps_str, sizeof(caps_str), "%b", caps, HN_CAP_BITS);
 	return sysctl_handle_string(oidp, caps_str, sizeof(caps_str), req);
 }