Index: sys/net/if_disc.c
===================================================================
--- sys/net/if_disc.c	(wersja 203490)
+++ sys/net/if_disc.c	(kopia robocza)
@@ -61,6 +61,8 @@
 
 #define DISCNAME	"disc"
 
+#define	DISC_CSUM_FEATURES	(CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
+
 struct disc_softc {
 	struct ifnet *sc_ifp;
 };
@@ -109,6 +111,8 @@
 	ifp->if_hdrlen = 0;
 	ifp->if_addrlen = 0;
 	ifp->if_snd.ifq_maxlen = 20;
+	ifp->if_capabilities = ifp->if_capenable = IFCAP_HWCSUM;
+	ifp->if_hwassist = DISC_CSUM_FEATURES;
 	if_attach(ifp);
 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
 
@@ -197,7 +201,7 @@
 {
 	struct ifaddr *ifa;
 	struct ifreq *ifr = (struct ifreq *)data;
-	int error = 0;
+	int error = 0, mask;
 
 	switch (cmd) {
 
@@ -238,6 +242,18 @@
 		ifp->if_mtu = ifr->ifr_mtu;
 		break;
 
+	case SIOCSIFCAP:
+		mask = ifp->if_capenable ^ ifr->ifr_reqcap;
+		if ((mask & IFCAP_RXCSUM) != 0)
+			ifp->if_capenable ^= IFCAP_RXCSUM;
+		if ((mask & IFCAP_TXCSUM) != 0)
+			ifp->if_capenable ^= IFCAP_TXCSUM;
+		if (ifp->if_capenable & IFCAP_TXCSUM)
+			ifp->if_hwassist = DISC_CSUM_FEATURES;
+		else
+			ifp->if_hwassist = 0;
+		break;
+
 	default:
 		error = EINVAL;
 	}