strace/sockaddr.c

/*
 * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
 * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
 * Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
 * Copyright (c) 1996-2000 Wichert Akkerman <wichert@cistron.nl>
 * Copyright (c) 2005-2016 Dmitry V. Levin <ldv@altlinux.org>
 * Copyright (c) 2016-2018 The strace developers.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "defs.h"
#include "print_fields.h"

#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "netlink.h"
#include <linux/ax25.h>
#include <linux/if_packet.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/rose.h>
#include <linux/x25.h>

#ifdef HAVE_NETIPX_IPX_H
# include <netipx/ipx.h>
#else
# include <linux/ipx.h>
#endif

#include "xlat/addrfams.h"
#include "xlat/arp_hardware_types.h"
#include "xlat/ethernet_protocols.h"
#include "xlat/af_packet_types.h"

#include "xlat/bdaddr_types.h"
#include "xlat/bluetooth_l2_cid.h"
#include "xlat/bluetooth_l2_psm.h"
#include "xlat/hci_channels.h"

#define SIZEOF_SA_FAMILY sizeof(((struct sockaddr *) 0)->sa_family)

const size_t arp_hardware_types_size = ARRAY_SIZE(arp_hardware_types) - 1;
const size_t ethernet_protocols_size = ARRAY_SIZE(ethernet_protocols) - 1;

static void
print_sockaddr_data_un(const void *const buf, const int addrlen)
{
	const struct sockaddr_un *const sa_un = buf;
	const int un_len = addrlen > (int) sizeof(*sa_un)
			   ? (int) sizeof(*sa_un) : addrlen;
	const int path_len = un_len - SIZEOF_SA_FAMILY;

	tprints("sun_path=");
	if (sa_un->sun_path[0]) {
		print_quoted_string(sa_un->sun_path, path_len + 1,
				    QUOTE_0_TERMINATED);
	} else {
		tprints("@");
		print_quoted_string(sa_un->sun_path + 1, path_len - 1, 0);
	}
}

bool
print_inet_addr(const int af,
		const void *const addr,
		const unsigned int len,
		const char *const var_name)
{
	char buf[INET6_ADDRSTRLEN];

	switch (af) {
	case AF_INET:
		if (inet_ntop(af, addr, buf, sizeof(buf))) {
			if (var_name)
				tprintf("%s=inet_addr(\"%s\")", var_name, buf);
			else
				tprints(buf);
			return true;
		}
		break;
	case AF_INET6:
		if (inet_ntop(af, addr, buf, sizeof(buf))) {
			if (var_name)
				tprintf("inet_pton(%s, \"%s\", &%s)",
					"AF_INET6", buf, var_name);
			else
				tprints(buf);
			return true;
		}
		break;
	}

	if (var_name)
		tprintf("%s=", var_name);
	print_quoted_string(addr, len, QUOTE_FORCE_HEX);
	return false;
}

bool
decode_inet_addr(struct tcb *const tcp,
		 const kernel_ulong_t addr,
		 const unsigned int len,
		 const int family,
		 const char *const var_name)
{
	union {
		struct in_addr  a4;
		struct in6_addr a6;
	} addrbuf;
	size_t size = 0;

	switch (family) {
	case AF_INET:
		size = sizeof(addrbuf.a4);
		break;
	case AF_INET6:
		size = sizeof(addrbuf.a6);
		break;
	}

	if (!size || len < size) {
		if (var_name)
			tprintf("%s=", var_name);
		printstr_ex(tcp, addr, len, QUOTE_FORCE_HEX);
		return false;
	}

	if (umoven(tcp, addr, size, &addrbuf) < 0) {
		if (var_name)
			tprintf("%s=", var_name);
		printaddr(addr);
		return false;
	}

	return print_inet_addr(family, &addrbuf, size, var_name);
}

static void
print_sockaddr_data_in(const void *const buf, const int addrlen)
{
	const struct sockaddr_in *const sa_in = buf;

	PRINT_FIELD_NET_PORT("", *sa_in, sin_port);
	PRINT_FIELD_INET4_ADDR(", ", *sa_in, sin_addr);
}

#define SIN6_MIN_LEN offsetof(struct sockaddr_in6, sin6_scope_id)

static void
print_sockaddr_data_in6(const void *const buf, const int addrlen)
{
	const struct sockaddr_in6 *const sa_in6 = buf;

	PRINT_FIELD_NET_PORT("", *sa_in6, sin6_port);
	PRINT_FIELD_INET_ADDR(", ", *sa_in6, sin6_addr, AF_INET6);
	tprintf(", sin6_flowinfo=htonl(%u)", ntohl(sa_in6->sin6_flowinfo));

	if (addrlen <= (int) SIN6_MIN_LEN)
		return;

#if defined IN6_IS_ADDR_LINKLOCAL && defined IN6_IS_ADDR_MC_LINKLOCAL
	if (IN6_IS_ADDR_LINKLOCAL(&sa_in6->sin6_addr)
	    || IN6_IS_ADDR_MC_LINKLOCAL(&sa_in6->sin6_addr))
		PRINT_FIELD_IFINDEX(", ", *sa_in6, sin6_scope_id);
	else
#endif
		PRINT_FIELD_U(", ", *sa_in6, sin6_scope_id);
}

/**
 * Check that we can print an AX.25 address in its native form, otherwise it
 * makes sense to print it in raw also (or in raw only).
 */
enum xlat_style
check_ax25_address(const ax25_address *addr)
{
	enum xlat_style ret = XLAT_STYLE_DEFAULT;
	bool space_seen = false;
	bool char_seen = false;

	for (size_t i = 0; i < ARRAY_SIZE(addr->ax25_call) - 1; i++) {
		unsigned char c = addr->ax25_call[i];

		/* The lowest bit should be zero */
		if (c & 1)
			ret = XLAT_STYLE_VERBOSE;

		c >>= 1;

		if (c == ' ')
			space_seen = true;
		else
			char_seen = true;

		/* Sane address contains only numbers and uppercase letters */
		if ((c < '0' || c > '9') && (c < 'A' || c > 'Z') && c != ' ')
			ret = XLAT_STYLE_VERBOSE;
		if (c != ' ' && space_seen)
			ret = XLAT_STYLE_VERBOSE;

		/* non-printable chars */
		if (c < ' ' || c > 0x7e
		    /* characters used for printing comments */
		    || c == '*' || c == '/')
			return XLAT_STYLE_RAW;
	}

	if (addr->ax25_call[ARRAY_SIZE(addr->ax25_call) - 1] & ~0x1e)
		ret = XLAT_STYLE_VERBOSE;

	if (!char_seen && addr->ax25_call[ARRAY_SIZE(addr->ax25_call) - 1])
		ret = XLAT_STYLE_VERBOSE;

	return ret;
}

/** Convert a (presumably) valid AX.25 to a string */
static const char *
ax25_addr2str(const ax25_address *addr)
{
	static char buf[ARRAY_SIZE(addr->ax25_call) + sizeof("-15")];
	char *p = buf;
	size_t end;

	for (end = ARRAY_SIZE(addr->ax25_call) - 1; end; end--)
		if ((addr->ax25_call[end - 1] >> 1) != ' ')
			break;

	for (size_t i = 0; i < end; i++)
		*p++ = ((unsigned char) addr->ax25_call[i]) >> 1;

	*p++ = '-';

	unsigned char ssid = (addr->ax25_call[ARRAY_SIZE(addr->ax25_call) - 1]
			      >> 1) & 0xf;

	if (ssid > 9) {
		*p++ = '1';
		ssid -= 10;
	}

	*p++ = ssid + '0';
	*p = '\0';

	if (buf[0] == '-' && buf[1] == '0')
		return "*";

	return buf;
}

static void
print_ax25_addr_raw(const ax25_address *addr)
{
	PRINT_FIELD_HEX_ARRAY("{", *addr, ax25_call);
	tprints("}");
}

void
print_ax25_addr(const void /* ax25_address */ *addr_void)
{
	const ax25_address *addr = addr_void;
	enum xlat_style xs = check_ax25_address(addr);

	if (xs == XLAT_STYLE_DEFAULT)
		xs = xlat_verbose(xlat_verbosity);

	if (xs != XLAT_STYLE_ABBREV)
		print_ax25_addr_raw(addr);

	if (xs == XLAT_STYLE_RAW)
		return;

	const char *addr_str = ax25_addr2str(addr);

	(xs == XLAT_STYLE_VERBOSE ? tprints_comment : tprints)(addr_str);
}

static void
print_sockaddr_data_ax25(const void *const buf, const int addrlen)
{
	const struct full_sockaddr_ax25 *const sax25 = buf;
	size_t addrlen_us = MAX(addrlen, 0);
	bool full = sax25->fsa_ax25.sax25_ndigis ||
	(addrlen_us > sizeof(struct sockaddr_ax25));

	if (full)
		tprints("fsa_ax25={");

	tprints("sax25_call=");
	print_ax25_addr(&sax25->fsa_ax25.sax25_call);
	PRINT_FIELD_D(", ", sax25->fsa_ax25, sax25_ndigis);

	if (!full)
		return;

	tprints("}");

	size_t has_digis = MIN((addrlen_us - sizeof(sax25->fsa_ax25))
			       / sizeof(sax25->fsa_digipeater[0]),
			       ARRAY_SIZE(sax25->fsa_digipeater));
	size_t want_digis = MIN(
		(unsigned int) MAX(sax25->fsa_ax25.sax25_ndigis, 0),
		ARRAY_SIZE(sax25->fsa_digipeater));
	size_t digis = MIN(has_digis, want_digis);

	if (want_digis == 0)
		goto digis_end;

	tprints(", fsa_digipeater=[");
	for (size_t i = 0; i < digis; i++) {
		if (i)
			tprints(", ");

		print_ax25_addr(sax25->fsa_digipeater + i);
	}

	if (want_digis > has_digis)
		tprintf("%s/* ??? */", digis ? ", " : "");

	tprints("]");

digis_end:
	if (addrlen_us > (has_digis * sizeof(sax25->fsa_digipeater[0])
		       + sizeof(sax25->fsa_ax25)))
		tprints(", ...");
}

static void
print_sockaddr_data_ipx(const void *const buf, const int addrlen)
{
	const struct sockaddr_ipx *const sa_ipx = buf;
	unsigned int i;

	PRINT_FIELD_NET_PORT("", *sa_ipx, sipx_port);
	tprintf(", sipx_network=htonl(%#08x)"
		", sipx_node=[",
		ntohl(sa_ipx->sipx_network));
	for (i = 0; i < IPX_NODE_LEN; ++i) {
		tprintf("%s%#02x", i ? ", " : "",
			sa_ipx->sipx_node[i]);
	}
	PRINT_FIELD_0X("], ", *sa_ipx, sipx_type);
}

void
print_x25_addr(const void /* struct x25_address */ *addr_void)
{
	const struct x25_address *addr = addr_void;

	tprints("{x25_addr=");
	print_quoted_cstring(addr->x25_addr, sizeof(addr->x25_addr));
	tprints("}");
}

static void
print_sockaddr_data_x25(const void *const buf, const int addrlen)
{
	const struct sockaddr_x25 *const sa_x25 = buf;

	PRINT_FIELD_X25_ADDR("", *sa_x25, sx25_addr);
}

void
print_rose_addr(const void /* rose_address */ *addr_void)
{
	const rose_address *addr = addr_void;

	if (IS_ARRAY_ZERO(addr->rose_addr)) {
		tprints("*");
		return;
	}

	tprintf("%02x%02x%02x%02x%02x",
		addr->rose_addr[0], addr->rose_addr[1], addr->rose_addr[2],
		addr->rose_addr[3], addr->rose_addr[4]);
}

static void
print_sockaddr_data_rose(const void *const buf, const int addrlen)
{
	const struct full_sockaddr_rose *const sa_rose = buf;
	size_t addrlen_us = MAX(addrlen, 0);

	PRINT_FIELD_ROSE_ADDR("", *sa_rose, srose_addr);
	PRINT_FIELD_X25_ADDR(", ", *sa_rose, srose_call);
	PRINT_FIELD_U(", ", *sa_rose, srose_ndigis);

	size_t has_digis = MIN((addrlen_us - offsetof(struct full_sockaddr_rose,
						      srose_digis))
			       / sizeof(sa_rose->srose_digis[0]),
			       ARRAY_SIZE(sa_rose->srose_digis));
	size_t want_digis =
		MIN(sa_rose->srose_ndigis, ARRAY_SIZE(sa_rose->srose_digis));
	size_t digis = MIN(has_digis, want_digis);

	if (want_digis == 0)
		goto digis_end;

	tprints(", srose_digis=[");
	for (size_t i = 0; i < digis; i++) {
		if (i)
			tprints(", ");

		print_ax25_addr(sa_rose->srose_digis + i);
	}

	if (want_digis > has_digis)
		tprintf("%s/* ??? */", digis ? ", " : "");

	tprints("]");

digis_end:
	if (addrlen_us > (has_digis * sizeof(sa_rose->srose_digis[0])
		       + offsetof(struct full_sockaddr_rose, srose_digis)))
		tprints(", ...");
}

static void
print_sockaddr_data_nl(const void *const buf, const int addrlen)
{
	const struct sockaddr_nl *const sa_nl = buf;

	PRINT_FIELD_D("", *sa_nl, nl_pid);
	PRINT_FIELD_0X(", ", *sa_nl, nl_groups);
}

static void
print_sockaddr_data_ll(const void *const buf, const int addrlen)
{
	const struct sockaddr_ll *const sa_ll = buf;

	tprints("sll_protocol=htons(");
	printxval(ethernet_protocols, ntohs(sa_ll->sll_protocol), "ETH_P_???");
	PRINT_FIELD_IFINDEX("), ", *sa_ll, sll_ifindex);
	tprints(", sll_hatype=");
	printxval(arp_hardware_types, sa_ll->sll_hatype, "ARPHRD_???");
	tprints(", sll_pkttype=");
	printxval(af_packet_types, sa_ll->sll_pkttype, "PACKET_???");
	tprintf(", sll_halen=%u", sa_ll->sll_halen);
	if (sa_ll->sll_halen) {
		const unsigned int oob_halen =
			addrlen - offsetof(struct sockaddr_ll, sll_addr);
		unsigned int i;

		tprints(", sll_addr=[");
		for (i = 0; i < sa_ll->sll_halen; ++i) {
			if (i)
				tprints(", ");
			if (i >= oob_halen) {
				tprints("...");
				break;
			}
			tprintf("%#02x", sa_ll->sll_addr[i]);
		}
		tprints("]");
	}
}

static void
print_sockaddr_data_raw(const void *const buf, const int addrlen)
{
	const char *const data = buf + SIZEOF_SA_FAMILY;
	const int datalen = addrlen - SIZEOF_SA_FAMILY;

	tprints("sa_data=");
	print_quoted_string(data, datalen, 0);
}

static uint16_t
btohs(uint16_t val)
{
#ifdef WORDS_BIGENDIAN
	return (val << 8) | (val >> 8);
#else
	return val;
#endif
}

static void
print_bluetooth_l2_psm(const char *prefix, uint16_t psm)
{
	const uint16_t psm_he = btohs(psm);
	const char *psm_name = xlookup(bluetooth_l2_psm, psm_he);
	const bool psm_str = psm_name || (psm_he >= L2CAP_PSM_LE_DYN_START
					  && psm_he <= L2CAP_PSM_LE_DYN_END)
				      || (psm_he >= L2CAP_PSM_DYN_START);

	tprintf("%shtobs(", prefix);

	if (xlat_verbose(xlat_verbosity) != XLAT_STYLE_ABBREV || !psm_str)
		tprintf("%#x", psm_he);

	if (xlat_verbose(xlat_verbosity) == XLAT_STYLE_RAW)
		goto print_bluetooth_l2_psm_end;

	if (xlat_verbose(xlat_verbosity) == XLAT_STYLE_VERBOSE || !psm_str)
		tprints(" /* ");

	if (psm_name) {
		tprints(psm_name);
	} else if (psm_he >= L2CAP_PSM_LE_DYN_START
	    && psm_he <= L2CAP_PSM_LE_DYN_END) {
		print_xlat(L2CAP_PSM_LE_DYN_START);
		tprintf(" + %u", psm_he - L2CAP_PSM_LE_DYN_START);
	} else if (psm_he >= L2CAP_PSM_DYN_START) {
		print_xlat(L2CAP_PSM_DYN_START);
		tprintf(" + %u", psm_he - L2CAP_PSM_DYN_START);
	} else {
		tprints("L2CAP_PSM_???");
	}

	if (xlat_verbose(xlat_verbosity) == XLAT_STYLE_VERBOSE || !psm_str)
		tprints(" */");

print_bluetooth_l2_psm_end:
	tprints(")");
}

static void
print_bluetooth_l2_cid(const char *prefix, uint16_t cid)
{
	const uint16_t cid_he = btohs(cid);
	const char *cid_name = xlookup(bluetooth_l2_cid, cid_he);
	const bool cid_str = cid_name || (cid_he >= L2CAP_CID_DYN_START);

	tprintf("%shtobs(", prefix);

	if (xlat_verbose(xlat_verbosity) != XLAT_STYLE_ABBREV || !cid_str)
		tprintf("%#x", cid_he);

	if (xlat_verbose(xlat_verbosity) == XLAT_STYLE_RAW)
		goto print_bluetooth_l2_cid_end;

	if (xlat_verbose(xlat_verbosity) == XLAT_STYLE_VERBOSE || !cid_str)
		tprints(" /* ");

	if (cid_name) {
		tprints(cid_name);
	} else if (cid_he >= L2CAP_CID_DYN_START) {
		print_xlat(L2CAP_CID_DYN_START);
		tprintf(" + %u", cid_he - L2CAP_CID_DYN_START);
	} else {
		tprints("L2CAP_CID_???");
	}

	if (xlat_verbose(xlat_verbosity) == XLAT_STYLE_VERBOSE || !cid_str)
		tprints(" */");

print_bluetooth_l2_cid_end:
	tprints(")");
}

static void
print_sockaddr_data_bt(const void *const buf, const int addrlen)
{
	struct sockaddr_hci {
		/* sa_family_t */ uint16_t	hci_family;
		uint16_t			hci_dev;
		uint16_t			hci_channel;
	};

	struct bdaddr {
		uint8_t				b[6];
	} ATTRIBUTE_PACKED;

	struct sockaddr_sco {
		/* sa_family_t */ uint16_t	sco_family;
		struct bdaddr			sco_bdaddr;
	};

	struct sockaddr_rc {
		/* sa_family_t */ uint16_t	rc_family;
		struct bdaddr			rc_bdaddr;
		uint8_t				rc_channel;
	};

	struct sockaddr_l2 {
		/* sa_family_t */ uint16_t	l2_family;
		/* little endian */ uint16_t	l2_psm;
		struct bdaddr			l2_bdaddr;
		/* little endian */ uint16_t	l2_cid;
		uint8_t				l2_bdaddr_type;
	};

	switch (addrlen) {
	case sizeof(struct sockaddr_hci): {
		const struct sockaddr_hci *const hci = buf;
		tprintf("hci_dev=htobs(%hu), hci_channel=",
			btohs(hci->hci_dev));
		printxval(hci_channels, hci->hci_channel, "HCI_CHANNEL_???");
		break;
	}
	case sizeof(struct sockaddr_sco): {
		const struct sockaddr_sco *const sco = buf;
		print_mac_addr("sco_bdaddr=", sco->sco_bdaddr.b,
			       sizeof(sco->sco_bdaddr.b));
		break;
	}
	case sizeof(struct sockaddr_rc): {
		const struct sockaddr_rc *const rc = buf;
		print_mac_addr("rc_bdaddr=", rc->rc_bdaddr.b,
			       sizeof(rc->rc_bdaddr.b));
		tprintf(", rc_channel=%u", rc->rc_channel);
		break;
	}
	case offsetof(struct sockaddr_l2, l2_bdaddr_type):
	case sizeof(struct sockaddr_l2): {
		const struct sockaddr_l2 *const l2 = buf;
		print_bluetooth_l2_psm("l2_psm=", l2->l2_psm);
		print_mac_addr(", l2_bdaddr=", l2->l2_bdaddr.b,
			       sizeof(l2->l2_bdaddr.b));
		print_bluetooth_l2_cid(", l2_cid=", l2->l2_cid);

		if (addrlen == sizeof(struct sockaddr_l2)) {
			tprints(", l2_bdaddr_type=");
			printxval(bdaddr_types, l2->l2_bdaddr_type,
				  "BDADDR_???");
		}

		break;
	}
	default:
		print_sockaddr_data_raw(buf, addrlen);
		break;
	}
}

typedef void (* const sockaddr_printer)(const void *const, const int);

static const struct {
	const sockaddr_printer printer;
	const int min_len;
} sa_printers[] = {
	[AF_UNIX] = { print_sockaddr_data_un, SIZEOF_SA_FAMILY + 1 },
	[AF_INET] = { print_sockaddr_data_in, sizeof(struct sockaddr_in) },
	[AF_AX25] = { print_sockaddr_data_ax25, sizeof(struct sockaddr_ax25) },
	[AF_IPX] = { print_sockaddr_data_ipx, sizeof(struct sockaddr_ipx) },
	[AF_X25] = { print_sockaddr_data_x25, sizeof(struct sockaddr_x25) },
	[AF_INET6] = { print_sockaddr_data_in6, SIN6_MIN_LEN },
	[AF_ROSE] = { print_sockaddr_data_rose, sizeof(struct sockaddr_rose) },
	[AF_NETLINK] = { print_sockaddr_data_nl, SIZEOF_SA_FAMILY + 1 },
	[AF_PACKET] = { print_sockaddr_data_ll, sizeof(struct sockaddr_ll) },
	[AF_BLUETOOTH] = { print_sockaddr_data_bt, SIZEOF_SA_FAMILY + 1 },
};

void
print_sockaddr(const void *const buf, const int addrlen)
{
	const struct sockaddr *const sa = buf;

	tprints("{sa_family=");
	printxval(addrfams, sa->sa_family, "AF_???");

	if (addrlen > (int) SIZEOF_SA_FAMILY) {
		tprints(", ");

		if (sa->sa_family < ARRAY_SIZE(sa_printers)
		    && sa_printers[sa->sa_family].printer
		    && addrlen >= sa_printers[sa->sa_family].min_len) {
			sa_printers[sa->sa_family].printer(buf, addrlen);
		} else {
			print_sockaddr_data_raw(buf, addrlen);
		}
	}

	tprints("}");
}

int
decode_sockaddr(struct tcb *const tcp, const kernel_ulong_t addr, int addrlen)
{
	if (addrlen < 2) {
		printaddr(addr);
		return -1;
	}

	union {
		struct sockaddr sa;
		struct sockaddr_storage storage;
		char pad[sizeof(struct sockaddr_storage) + 1];
	} addrbuf;

	if ((unsigned) addrlen > sizeof(addrbuf.storage))
		addrlen = sizeof(addrbuf.storage);

	if (umoven_or_printaddr(tcp, addr, addrlen, addrbuf.pad))
		return -1;

	memset(&addrbuf.pad[addrlen], 0, sizeof(addrbuf.pad) - addrlen);

	print_sockaddr(&addrbuf, addrlen);

	return addrbuf.sa.sa_family;
}