diff --git a/sock.c b/sock.c
index 48bf74b..97d8afa 100644
--- a/sock.c
+++ b/sock.c
@@ -41,14 +41,19 @@
 #include "xlat/iffflags.h"
 
 static void
-print_addr(struct tcb *tcp, long addr, struct ifreq *ifr)
+print_ifreq_addr(struct tcb *tcp, const struct ifreq *ifr, const long addr)
 {
+	tprintf("{");
+	printxval(addrfams, ifr->ifr_addr.sa_family, "AF_???");
+	tprints(", ");
 	if (ifr->ifr_addr.sa_family == AF_INET) {
-		struct sockaddr_in *sinp;
-		sinp = (struct sockaddr_in *) &ifr->ifr_addr;
+		const struct sockaddr_in *sinp =
+			(struct sockaddr_in *) &ifr->ifr_addr;
 		tprintf("inet_addr(\"%s\")", inet_ntoa(sinp->sin_addr));
 	} else
-		printstr(tcp, addr, sizeof(ifr->ifr_addr.sa_data));
+		printstr(tcp, addr + offsetof(struct ifreq, ifr_addr.sa_data),
+			 sizeof(ifr->ifr_addr.sa_data));
+	tprints("}");
 }
 
 static void
@@ -57,238 +62,291 @@
 	print_quoted_string(ifname, IFNAMSIZ + 1, QUOTE_0_TERMINATED);
 }
 
-int
-sock_ioctl(struct tcb *tcp, const unsigned int code, long arg)
+static void
+print_ifreq(struct tcb *tcp, const unsigned int code, const long arg,
+	    const struct ifreq *ifr)
 {
-	struct ifreq ifr;
+	switch (code) {
+	case SIOCSIFADDR:
+	case SIOCGIFADDR:
+		tprints("ifr_addr=");
+		print_ifreq_addr(tcp, ifr, arg);
+		break;
+	case SIOCSIFDSTADDR:
+	case SIOCGIFDSTADDR:
+		tprints("ifr_dstaddr=");
+		print_ifreq_addr(tcp, ifr, arg);
+		break;
+	case SIOCSIFBRDADDR:
+	case SIOCGIFBRDADDR:
+		tprints("ifr_broadaddr=");
+		print_ifreq_addr(tcp, ifr, arg);
+		break;
+	case SIOCSIFNETMASK:
+	case SIOCGIFNETMASK:
+		tprints("ifr_netmask=");
+		print_ifreq_addr(tcp, ifr, arg);
+		break;
+	case SIOCSIFHWADDR:
+	case SIOCGIFHWADDR: {
+		/* XXX Are there other hardware addresses
+		   than 6-byte MACs?  */
+		const unsigned char *bytes =
+			(unsigned char *) &ifr->ifr_hwaddr.sa_data;
+		tprintf("ifr_hwaddr=%02x:%02x:%02x:%02x:%02x:%02x",
+			bytes[0], bytes[1], bytes[2],
+			bytes[3], bytes[4], bytes[5]);
+		break;
+	}
+	case SIOCSIFFLAGS:
+	case SIOCGIFFLAGS:
+		tprints("ifr_flags=");
+		printflags(iffflags, ifr->ifr_flags, "IFF_???");
+		break;
+	case SIOCSIFMETRIC:
+	case SIOCGIFMETRIC:
+		tprintf("ifr_metric=%d", ifr->ifr_metric);
+		break;
+	case SIOCSIFMTU:
+	case SIOCGIFMTU:
+		tprintf("ifr_mtu=%d", ifr->ifr_mtu);
+		break;
+	case SIOCSIFSLAVE:
+	case SIOCGIFSLAVE:
+		tprints("ifr_slave=");
+		print_ifname(ifr->ifr_slave);
+		break;
+	case SIOCSIFTXQLEN:
+	case SIOCGIFTXQLEN:
+		tprintf("ifr_qlen=%d", ifr->ifr_qlen);
+		break;
+	case SIOCSIFMAP:
+	case SIOCGIFMAP:
+		tprintf("ifr_map={mem_start=%#lx, "
+			"mem_end=%#lx, base_addr=%#x, "
+			"irq=%u, dma=%u, port=%u}",
+			ifr->ifr_map.mem_start,
+			ifr->ifr_map.mem_end,
+			(unsigned) ifr->ifr_map.base_addr,
+			(unsigned) ifr->ifr_map.irq,
+			(unsigned) ifr->ifr_map.dma,
+			(unsigned) ifr->ifr_map.port);
+		break;
+	}
+}
+
+static unsigned int
+print_ifc_len(int len)
+{
+	const unsigned int n = (unsigned int) len / sizeof(struct ifreq);
+
+	if (len < 0 || n * sizeof(struct ifreq) != (unsigned int) len)
+		tprintf("%d", len);
+	else
+		tprintf("%u * sizeof(struct ifreq)", n);
+
+	return n;
+}
+
+static int
+decode_ifconf(struct tcb *tcp, const long addr)
+{
 	struct ifconf ifc;
-	const char *str = NULL;
-	unsigned char *bytes;
 
 	if (entering(tcp)) {
-		switch (code) {
-		case SIOCGIFCONF:
-			if (umove(tcp, tcp->u_arg[2], &ifc) >= 0
-			    && ifc.ifc_buf == NULL)
-				tprintf(", {%d -> ", ifc.ifc_len);
-			else
-				tprints(", {");
-			break;
-		case SIOCSIFNAME:
-			if (umove(tcp, tcp->u_arg[2], &ifr) < 0)
-				tprintf(", %#lx", tcp->u_arg[2]);
-			else {
-				tprints(", {ifr_name=");
-				print_ifname(ifr.ifr_name);
-				tprints(", ifr_newname=");
-				print_ifname(ifr.ifr_newname);
-				tprints("}");
-			}
-			break;
+		tprints(", ");
+		if (umove_or_printaddr(tcp, addr, &ifc))
+			return RVAL_DECODED | 1;
+		if (ifc.ifc_buf) {
+			tprints("{");
+			print_ifc_len(ifc.ifc_len);
 		}
-		return 0;
+		return 1;
 	}
 
+	if (syserror(tcp) || umove(tcp, addr, &ifc) < 0) {
+		if (ifc.ifc_buf)
+			tprints("}");
+		else
+			printaddr(addr);
+		return RVAL_DECODED | 1;
+	}
+
+	if (!ifc.ifc_buf) {
+		tprints("{");
+		print_ifc_len(ifc.ifc_len);
+		tprints(", NULL}");
+		return RVAL_DECODED | 1;
+	}
+
+	tprints(" => ");
+	const unsigned int nifra = print_ifc_len(ifc.ifc_len);
+	if (!nifra) {
+		tprints("}");
+		return RVAL_DECODED | 1;
+	}
+
+	struct ifreq ifra[nifra > max_strlen ? max_strlen : nifra];
+	tprints(", ");
+	if (umove_or_printaddr(tcp, (unsigned long) ifc.ifc_buf, &ifra)) {
+		tprints("}");
+		return RVAL_DECODED | 1;
+	}
+
+	tprints("[");
+	unsigned int i;
+	for (i = 0; i < ARRAY_SIZE(ifra); ++i) {
+		if (i > 0)
+			tprints(", ");
+		tprints("{ifr_name=");
+		print_ifname(ifra[i].ifr_name);
+		tprints(", ");
+		if (verbose(tcp)) {
+			tprints("ifr_addr=");
+			print_ifreq_addr(tcp, &ifra[i],
+					 addr + i * sizeof(ifra[0]));
+		} else
+			tprints("...");
+		tprints("}");
+	}
+	if (i < nifra)
+		tprints(", ...");
+	tprints("]}");
+
+	return RVAL_DECODED | 1;
+}
+
+int
+sock_ioctl(struct tcb *tcp, const unsigned int code, const long arg)
+{
+	struct ifreq ifr;
+
 	switch (code) {
-#ifdef SIOCSHIWAT
-	case SIOCSHIWAT:
+	case SIOCGIFCONF:
+		return decode_ifconf(tcp, arg);
+
+#ifdef SIOCBRADDBR
+	case SIOCBRADDBR:
+	case SIOCBRDELBR:
+		tprints(", ");
+		printstr(tcp, arg, -1);
+		break;
 #endif
-#ifdef SIOCGHIWAT
-	case SIOCGHIWAT:
-#endif
-#ifdef SIOCSLOWAT
-	case SIOCSLOWAT:
-#endif
-#ifdef SIOCGLOWAT
-	case SIOCGLOWAT:
-#endif
+
 #ifdef FIOSETOWN
 	case FIOSETOWN:
 #endif
-#ifdef FIOGETOWN
-	case FIOGETOWN:
-#endif
 #ifdef SIOCSPGRP
 	case SIOCSPGRP:
 #endif
+		tprints(", ");
+		printnum_int(tcp, arg, "%d");
+		break;
+
+#ifdef FIOGETOWN
+	case FIOGETOWN:
+#endif
 #ifdef SIOCGPGRP
 	case SIOCGPGRP:
 #endif
 #ifdef SIOCATMARK
 	case SIOCATMARK:
 #endif
-		printnum_int(tcp, arg, ", %d");
+		if (entering(tcp))
+			return 0;
+		tprints(", ");
+		printnum_int(tcp, arg, "%d");
+		break;
+
+#ifdef SIOCBRADDIF
+	case SIOCBRADDIF:
+#endif
+#ifdef SIOCBRDELIF
+	case SIOCBRDELIF:
+#endif
+		/* no arguments */
+		break;
+
 	case SIOCSIFNAME:
-		return 1;
+	case SIOCSIFADDR:
+	case SIOCSIFDSTADDR:
+	case SIOCSIFBRDADDR:
+	case SIOCSIFNETMASK:
+	case SIOCSIFFLAGS:
+	case SIOCSIFMETRIC:
+	case SIOCSIFMTU:
+	case SIOCSIFSLAVE:
+	case SIOCSIFHWADDR:
+	case SIOCSIFTXQLEN:
+	case SIOCSIFMAP:
+		tprints(", ");
+		if (umove_or_printaddr(tcp, arg, &ifr))
+			break;
+
+		tprints("{ifr_name=");
+		print_ifname(ifr.ifr_name);
+		tprints(", ");
+		if (code == SIOCSIFNAME) {
+			tprints("ifr_newname=");
+			print_ifname(ifr.ifr_newname);
+		} else {
+			print_ifreq(tcp, code, arg, &ifr);
+		}
+		tprints("}");
+		break;
+
 	case SIOCGIFNAME:
 	case SIOCGIFINDEX:
 	case SIOCGIFADDR:
-	case SIOCSIFADDR:
 	case SIOCGIFDSTADDR:
-	case SIOCSIFDSTADDR:
 	case SIOCGIFBRDADDR:
-	case SIOCSIFBRDADDR:
 	case SIOCGIFNETMASK:
-	case SIOCSIFNETMASK:
 	case SIOCGIFFLAGS:
-	case SIOCSIFFLAGS:
 	case SIOCGIFMETRIC:
-	case SIOCSIFMETRIC:
 	case SIOCGIFMTU:
-	case SIOCSIFMTU:
 	case SIOCGIFSLAVE:
-	case SIOCSIFSLAVE:
 	case SIOCGIFHWADDR:
-	case SIOCSIFHWADDR:
 	case SIOCGIFTXQLEN:
-	case SIOCSIFTXQLEN:
 	case SIOCGIFMAP:
-	case SIOCSIFMAP:
-		if (umove(tcp, tcp->u_arg[2], &ifr) < 0)
-			tprintf(", %#lx", tcp->u_arg[2]);
-		else if (syserror(tcp)) {
-			if (code == SIOCGIFNAME) {
-				tprintf(", {ifr_index=%d, ifr_name=???}",
-					ifr.ifr_ifindex);
-			} else {
-				tprints(", {ifr_name=");
-				print_ifname(ifr.ifr_name);
-				tprints(", ???}");
-			}
-		} else if (code == SIOCGIFNAME) {
-			tprintf(", {ifr_index=%d, ifr_name=", ifr.ifr_ifindex);
-			print_ifname(ifr.ifr_name);
-			tprints("}");
-		} else {
-			tprints(", {ifr_name=");
-			print_ifname(ifr.ifr_name);
+		if (entering(tcp)) {
 			tprints(", ");
-			switch (code) {
-			case SIOCGIFINDEX:
-				tprintf("ifr_index=%d", ifr.ifr_ifindex);
+			if (umove_or_printaddr(tcp, arg, &ifr))
 				break;
-			case SIOCGIFADDR:
-			case SIOCSIFADDR:
-				str = "ifr_addr";
-			case SIOCGIFDSTADDR:
-			case SIOCSIFDSTADDR:
-				if (!str)
-					str = "ifr_dstaddr";
-			case SIOCGIFBRDADDR:
-			case SIOCSIFBRDADDR:
-				if (!str)
-					str = "ifr_broadaddr";
-			case SIOCGIFNETMASK:
-			case SIOCSIFNETMASK:
-				if (!str)
-					str = "ifr_netmask";
-				tprintf("%s={", str);
-				printxval(addrfams,
-					  ifr.ifr_addr.sa_family,
-					  "AF_???");
-				tprints(", ");
-				print_addr(tcp, ((long) tcp->u_arg[2]
-						 + offsetof(struct ifreq,
-							     ifr_addr.sa_data)),
-					   &ifr);
+
+			if (SIOCGIFNAME == code) {
+				tprintf("{ifr_index=%d", ifr.ifr_ifindex);
+			} else {
+				tprints("{ifr_name=");
+				print_ifname(ifr.ifr_name);
+			}
+			return 1;
+		} else {
+			if (syserror(tcp)) {
 				tprints("}");
 				break;
-			case SIOCGIFHWADDR:
-			case SIOCSIFHWADDR:
-				/* XXX Are there other hardware addresses
-				   than 6-byte MACs?  */
-				bytes = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
-				tprintf("ifr_hwaddr=%02x:%02x:%02x:%02x:%02x:%02x",
-					bytes[0], bytes[1], bytes[2],
-					bytes[3], bytes[4], bytes[5]);
-				break;
-			case SIOCGIFFLAGS:
-			case SIOCSIFFLAGS:
-				tprints("ifr_flags=");
-				printflags(iffflags, ifr.ifr_flags, "IFF_???");
-				break;
-			case SIOCGIFMETRIC:
-			case SIOCSIFMETRIC:
-				tprintf("ifr_metric=%d", ifr.ifr_metric);
-				break;
-			case SIOCGIFMTU:
-			case SIOCSIFMTU:
-				tprintf("ifr_mtu=%d", ifr.ifr_mtu);
-				break;
-			case SIOCGIFSLAVE:
-			case SIOCSIFSLAVE:
-				tprints("ifr_slave=");
-				print_ifname(ifr.ifr_slave);
-				break;
-			case SIOCGIFTXQLEN:
-			case SIOCSIFTXQLEN:
-				tprintf("ifr_qlen=%d", ifr.ifr_qlen);
-				break;
-			case SIOCGIFMAP:
-			case SIOCSIFMAP:
-				tprintf("ifr_map={mem_start=%#lx, "
-					"mem_end=%#lx, base_addr=%#x, "
-					"irq=%u, dma=%u, port=%u}",
-					ifr.ifr_map.mem_start,
-					ifr.ifr_map.mem_end,
-					(unsigned) ifr.ifr_map.base_addr,
-					(unsigned) ifr.ifr_map.irq,
-					(unsigned) ifr.ifr_map.dma,
-					(unsigned) ifr.ifr_map.port);
-				break;
 			}
-			tprints("}");
-		}
-		return 1;
-	case SIOCGIFCONF:
-		if (umove(tcp, tcp->u_arg[2], &ifc) < 0) {
-			tprints("???}");
-			return 1;
-		}
-		tprintf("%d, ", ifc.ifc_len);
-		if (syserror(tcp)) {
-			tprintf("%lx", (unsigned long) ifc.ifc_buf);
-		} else if (ifc.ifc_buf == NULL) {
-			tprints("NULL");
-		} else {
-			unsigned int i;
-			unsigned int nifra = ifc.ifc_len / sizeof(struct ifreq);
-			struct ifreq ifra[nifra];
 
-			if (umoven(tcp, (unsigned long) ifc.ifc_buf,
-				sizeof(ifra), ifra) < 0) {
-				tprintf("%lx}", (unsigned long) ifc.ifc_buf);
-				return 1;
+			tprints(", ");
+			if (umove(tcp, arg, &ifr) < 0) {
+				tprints("???}");
+				break;
 			}
-			tprints("{");
-			for (i = 0; i < nifra; ++i ) {
-				if (i > 0)
-					tprints(", ");
-				tprints("{");
-				print_ifname(ifra[i].ifr_newname);
-				tprints(", {");
-				if (verbose(tcp)) {
-					printxval(addrfams,
-						  ifra[i].ifr_addr.sa_family,
-						  "AF_???");
-					tprints(", ");
-					print_addr(tcp, ((long) tcp->u_arg[2]
-							 + offsetof(struct ifreq,
-								     ifr_addr.sa_data)
-							 + ((char *) &ifra[i]
-							    - (char *) &ifra[0])),
-						   &ifra[i]);
-				} else
-					tprints("...");
-				tprints("}}");
+
+			if (SIOCGIFNAME == code) {
+				tprints("ifr_name=");
+				print_ifname(ifr.ifr_name);
+			} else {
+				print_ifreq(tcp, code, arg, &ifr);
 			}
 			tprints("}");
+			break;
 		}
-		tprints("}");
-		return 1;
+
 	default:
-		return 0;
+		return RVAL_DECODED;
 	}
+
+	return RVAL_DECODED | 1;
 }
 
 SYS_FUNC(socketcall)