[tor-commits] [tor/release-0.4.0] Merge remote-tracking branch 'bug28525_029' into maint-0.3.5

asn at torproject.org asn at torproject.org
Tue Mar 12 16:14:01 UTC 2019


commit 08ddf1f62bf62aa3dc044e0570fb368477223688
Merge: d6f77b99d 63b404911
Author: teor <teor at torproject.org>
Date:   Fri Mar 8 12:32:04 2019 +1000

    Merge remote-tracking branch 'bug28525_029' into maint-0.3.5

 changes/bug28525      |  8 ++++++++
 src/lib/net/address.c | 19 +++++++++++++++----
 src/test/test_addr.c  | 18 ++++++++++++++++++
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --cc src/lib/net/address.c
index 28c8e3f50,000000000..a2d234b74
mode 100644,000000..100644
--- a/src/lib/net/address.c
+++ b/src/lib/net/address.c
@@@ -1,2046 -1,0 +1,2057 @@@
 +/* Copyright (c) 2003-2004, Roger Dingledine
 + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
 + * Copyright (c) 2007-2019, The Tor Project, Inc. */
 +/* See LICENSE for licensing information */
 +
 +/**
 + * \file address.c
 + * \brief Functions to use and manipulate the tor_addr_t structure.
 + *
 + * This module doesn't have any support for the libc resolver: that is all in
 + * resolve.c.
 + **/
 +
 +#define ADDRESS_PRIVATE
 +
 +#include "orconfig.h"
 +
 +#ifdef _WIN32
 +/* For access to structs needed by GetAdaptersAddresses */
 +#ifndef WIN32_LEAN_AND_MEAN
 +#error "orconfig.h didn't define WIN32_LEAN_AND_MEAN"
 +#endif
 +#ifndef WINVER
 +#error "orconfig.h didn't define WINVER"
 +#endif
 +#ifndef _WIN32_WINNT
 +#error "orconfig.h didn't define _WIN32_WINNT"
 +#endif
 +#if WINVER < 0x0501
 +#error "winver too low"
 +#endif
 +#if _WIN32_WINNT < 0x0501
 +#error "winver too low"
 +#endif
 +#include <winsock2.h>
 +#include <process.h>
 +#include <windows.h>
 +#include <iphlpapi.h>
 +#endif /* defined(_WIN32) */
 +
 +#include "lib/net/address.h"
 +#include "lib/net/socket.h"
 +#include "lib/container/smartlist.h"
 +#include "lib/ctime/di_ops.h"
 +#include "lib/log/log.h"
 +#include "lib/log/escape.h"
 +#include "lib/malloc/malloc.h"
 +#include "lib/net/inaddr.h"
 +#include "lib/string/compat_ctype.h"
 +#include "lib/string/compat_string.h"
 +#include "lib/string/parse_int.h"
 +#include "lib/string/printf.h"
 +#include "lib/string/util_string.h"
 +
 +#include "siphash.h"
 +
 +#ifdef HAVE_SYS_TIME_H
 +#include <sys/time.h>
 +#endif
 +#ifdef HAVE_UNISTD_H
 +#include <unistd.h>
 +#endif
 +#ifdef HAVE_ERRNO_H
 +#include <errno.h>
 +#endif
 +#ifdef HAVE_ARPA_INET_H
 +#include <arpa/inet.h>
 +#endif
 +#ifdef HAVE_SYS_SOCKET_H
 +#include <sys/socket.h>
 +#endif
 +#ifdef HAVE_NETDB_H
 +#include <netdb.h>
 +#endif
 +#ifdef HAVE_SYS_PARAM_H
 +#include <sys/param.h> /* FreeBSD needs this to know what version it is */
 +#endif
 +#ifdef HAVE_SYS_UN_H
 +#include <sys/un.h>
 +#endif
 +#ifdef HAVE_IFADDRS_H
 +#include <ifaddrs.h>
 +#endif
 +#ifdef HAVE_SYS_IOCTL_H
 +#include <sys/ioctl.h>
 +#endif
 +#ifdef HAVE_NET_IF_H
 +#include <net/if.h>
 +#endif
 +#include <stdarg.h>
 +#include <stdio.h>
 +#include <stdlib.h>
 +#include <string.h>
 +
 +/* tor_addr_is_null() and maybe other functions rely on AF_UNSPEC being 0 to
 + * work correctly. Bail out here if we've found a platform where AF_UNSPEC
 + * isn't 0. */
 +#if AF_UNSPEC != 0
 +#error We rely on AF_UNSPEC being 0. Let us know about your platform, please!
 +#endif
 +
 +/** Convert the tor_addr_t in <b>a</b>, with port in <b>port</b>, into a
 + * sockaddr object in *<b>sa_out</b> of object size <b>len</b>.  If not enough
 + * room is available in sa_out, or on error, return 0.  On success, return
 + * the length of the sockaddr.
 + *
 + * Interface note: ordinarily, we return -1 for error.  We can't do that here,
 + * since socklen_t is unsigned on some platforms.
 + **/
 +socklen_t
 +tor_addr_to_sockaddr(const tor_addr_t *a,
 +                     uint16_t port,
 +                     struct sockaddr *sa_out,
 +                     socklen_t len)
 +{
 +  memset(sa_out, 0, len);
 +
 +  sa_family_t family = tor_addr_family(a);
 +  if (family == AF_INET) {
 +    struct sockaddr_in *sin;
 +    if (len < (int)sizeof(struct sockaddr_in))
 +      return 0;
 +    sin = (struct sockaddr_in *)sa_out;
 +#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
 +    sin->sin_len = sizeof(struct sockaddr_in);
 +#endif
 +    sin->sin_family = AF_INET;
 +    sin->sin_port = htons(port);
 +    sin->sin_addr.s_addr = tor_addr_to_ipv4n(a);
 +    return sizeof(struct sockaddr_in);
 +  } else if (family == AF_INET6) {
 +    struct sockaddr_in6 *sin6;
 +    if (len < (int)sizeof(struct sockaddr_in6))
 +      return 0;
 +    sin6 = (struct sockaddr_in6 *)sa_out;
 +#ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_LEN
 +    sin6->sin6_len = sizeof(struct sockaddr_in6);
 +#endif
 +    sin6->sin6_family = AF_INET6;
 +    sin6->sin6_port = htons(port);
 +    memcpy(&sin6->sin6_addr, tor_addr_to_in6_assert(a),
 +           sizeof(struct in6_addr));
 +    return sizeof(struct sockaddr_in6);
 +  } else {
 +    return 0;
 +  }
 +}
 +
 +/** Set address <b>a</b> to zero.  This address belongs to
 + * the AF_UNIX family. */
 +static void
 +tor_addr_make_af_unix(tor_addr_t *a)
 +{
 +  memset(a, 0, sizeof(*a));
 +  a->family = AF_UNIX;
 +}
 +
 +/** Set the tor_addr_t in <b>a</b> to contain the socket address contained in
 + * <b>sa</b>.  IF <b>port_out</b> is non-NULL and <b>sa</b> contains a port,
 + * set *<b>port_out</b> to that port. Return 0 on success and -1 on
 + * failure. */
 +int
 +tor_addr_from_sockaddr(tor_addr_t *a, const struct sockaddr *sa,
 +                       uint16_t *port_out)
 +{
 +  tor_assert(a);
 +  tor_assert(sa);
 +
 +  /* This memset is redundant; leaving it in to avoid any future accidents,
 +     however. */
 +  memset(a, 0, sizeof(*a));
 +
 +  if (sa->sa_family == AF_INET) {
 +    struct sockaddr_in *sin = (struct sockaddr_in *) sa;
 +    tor_addr_from_ipv4n(a, sin->sin_addr.s_addr);
 +    if (port_out)
 +      *port_out = ntohs(sin->sin_port);
 +  } else if (sa->sa_family == AF_INET6) {
 +    struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) sa;
 +    tor_addr_from_in6(a, &sin6->sin6_addr);
 +    if (port_out)
 +      *port_out = ntohs(sin6->sin6_port);
 +  } else if (sa->sa_family == AF_UNIX) {
 +    tor_addr_make_af_unix(a);
 +    return 0;
 +  } else {
 +    tor_addr_make_unspec(a);
 +    return -1;
 +  }
 +  return 0;
 +}
 +
 +/** Return a newly allocated string holding the address described in
 + * <b>sa</b>.  AF_UNIX, AF_UNSPEC, AF_INET, and AF_INET6 are supported. */
 +char *
 +tor_sockaddr_to_str(const struct sockaddr *sa)
 +{
 +  char address[TOR_ADDR_BUF_LEN];
 +  char *result;
 +  tor_addr_t addr;
 +  uint16_t port;
 +#ifdef HAVE_SYS_UN_H
 +  if (sa->sa_family == AF_UNIX) {
 +    struct sockaddr_un *s_un = (struct sockaddr_un *)sa;
 +    tor_asprintf(&result, "unix:%s", s_un->sun_path);
 +    return result;
 +  }
 +#endif /* defined(HAVE_SYS_UN_H) */
 +  if (sa->sa_family == AF_UNSPEC)
 +    return tor_strdup("unspec");
 +
 +  if (tor_addr_from_sockaddr(&addr, sa, &port) < 0)
 +    return NULL;
 +  if (! tor_addr_to_str(address, &addr, sizeof(address), 1))
 +    return NULL;
 +  tor_asprintf(&result, "%s:%d", address, (int)port);
 +  return result;
 +}
 +
 +/** Set address <b>a</b> to the unspecified address.  This address belongs to
 + * no family. */
 +void
 +tor_addr_make_unspec(tor_addr_t *a)
 +{
 +  memset(a, 0, sizeof(*a));
 +  a->family = AF_UNSPEC;
 +}
 +
 +/** Set address <b>a</b> to the null address in address family <b>family</b>.
 + * The null address for AF_INET is 0.0.0.0.  The null address for AF_INET6 is
 + * [::].  AF_UNSPEC is all null. */
 +void
 +tor_addr_make_null(tor_addr_t *a, sa_family_t family)
 +{
 +  memset(a, 0, sizeof(*a));
 +  a->family = family;
 +}
 +
- /** Return true iff <b>ip</b> is an IP reserved to localhost or local networks
-  * in RFC1918 or RFC4193 or RFC4291. (fec0::/10, deprecated by RFC3879, is
-  * also treated as internal for now.)
++/** Return true iff <b>ip</b> is an IP reserved to localhost or local networks.
++ *
++ * If <b>ip</b> is in RFC1918 or RFC4193 or RFC4291, we will return true.
++ * (fec0::/10, deprecated by RFC3879, is also treated as internal for now
++ * and will return true.)
++ *
++ * If <b>ip</b> is 0.0.0.0 or 100.64.0.0/10 (RFC6598), we will act as:
++ *  - Internal if <b>for_listening</b> is 0, as these addresses are not
++ *    routable on the internet and we won't be publicly accessible to clients.
++ *  - External if <b>for_listening</b> is 1, as clients could connect to us
++ *    from the internet (in the case of 0.0.0.0) or a service provider's
++ *    internal network (in the case of RFC6598).
 + */
 +int
 +tor_addr_is_internal_(const tor_addr_t *addr, int for_listening,
 +                      const char *filename, int lineno)
 +{
 +  uint32_t iph4 = 0;
 +  uint32_t iph6[4];
 +
 +  tor_assert(addr);
 +  sa_family_t v_family = tor_addr_family(addr);
 +
 +  if (v_family == AF_INET) {
 +    iph4 = tor_addr_to_ipv4h(addr);
 +  } else if (v_family == AF_INET6) {
 +    if (tor_addr_is_v4(addr)) { /* v4-mapped */
 +      uint32_t *addr32 = NULL;
 +      v_family = AF_INET;
 +      // Work around an incorrect NULL pointer dereference warning in
 +      // "clang --analyze" due to limited analysis depth
 +      addr32 = tor_addr_to_in6_addr32(addr);
 +      // To improve performance, wrap this assertion in:
 +      // #if !defined(__clang_analyzer__) || PARANOIA
 +      tor_assert(addr32);
 +      iph4 = ntohl(addr32[3]);
 +    }
 +  }
 +
 +  if (v_family == AF_INET6) {
 +    const uint32_t *a32 = tor_addr_to_in6_addr32(addr);
 +    iph6[0] = ntohl(a32[0]);
 +    iph6[1] = ntohl(a32[1]);
 +    iph6[2] = ntohl(a32[2]);
 +    iph6[3] = ntohl(a32[3]);
 +    if (for_listening && !iph6[0] && !iph6[1] && !iph6[2] && !iph6[3]) /* :: */
 +      return 0;
 +
 +    if (((iph6[0] & 0xfe000000) == 0xfc000000) || /* fc00/7  - RFC4193 */
 +        ((iph6[0] & 0xffc00000) == 0xfe800000) || /* fe80/10 - RFC4291 */
 +        ((iph6[0] & 0xffc00000) == 0xfec00000))   /* fec0/10 D- RFC3879 */
 +      return 1;
 +
 +    if (!iph6[0] && !iph6[1] && !iph6[2] &&
 +        ((iph6[3] & 0xfffffffe) == 0x00000000))  /* ::/127 */
 +      return 1;
 +
 +    return 0;
 +  } else if (v_family == AF_INET) {
-     if (for_listening && !iph4) /* special case for binding to 0.0.0.0 */
++    /* special case for binding to 0.0.0.0 or 100.64/10 (RFC6598) */
++    if (for_listening && (!iph4 || ((iph4 & 0xffc00000) == 0x64400000)))
 +      return 0;
 +    if (((iph4 & 0xff000000) == 0x0a000000) || /*       10/8 */
 +        ((iph4 & 0xff000000) == 0x00000000) || /*        0/8 */
 +        ((iph4 & 0xff000000) == 0x7f000000) || /*      127/8 */
++        ((iph4 & 0xffc00000) == 0x64400000) || /*  100.64/10 */
 +        ((iph4 & 0xffff0000) == 0xa9fe0000) || /* 169.254/16 */
 +        ((iph4 & 0xfff00000) == 0xac100000) || /*  172.16/12 */
 +        ((iph4 & 0xffff0000) == 0xc0a80000))   /* 192.168/16 */
 +      return 1;
 +    return 0;
 +  }
 +
 +  /* unknown address family... assume it's not safe for external use */
 +  /* rather than tor_assert(0) */
 +  log_warn(LD_BUG, "tor_addr_is_internal() called from %s:%d with a "
 +           "non-IP address of type %d", filename, lineno, (int)v_family);
 +  tor_fragile_assert();
 +  return 1;
 +}
 +
 +/** Convert a tor_addr_t <b>addr</b> into a string, and store it in
 + *  <b>dest</b> of size <b>len</b>.  Returns a pointer to dest on success,
 + *  or NULL on failure.  If <b>decorate</b>, surround IPv6 addresses with
 + *  brackets.
 + */
 +const char *
 +tor_addr_to_str(char *dest, const tor_addr_t *addr, size_t len, int decorate)
 +{
 +  const char *ptr;
 +  tor_assert(addr && dest);
 +
 +  switch (tor_addr_family(addr)) {
 +    case AF_INET:
 +      /* Shortest addr x.x.x.x + \0 */
 +      if (len < 8)
 +        return NULL;
 +      ptr = tor_inet_ntop(AF_INET, &addr->addr.in_addr, dest, len);
 +      break;
 +    case AF_INET6:
 +      /* Shortest addr [ :: ] + \0 */
 +      if (len < (3 + (decorate ? 2 : 0)))
 +        return NULL;
 +
 +      if (decorate)
 +        ptr = tor_inet_ntop(AF_INET6, &addr->addr.in6_addr, dest+1, len-2);
 +      else
 +        ptr = tor_inet_ntop(AF_INET6, &addr->addr.in6_addr, dest, len);
 +
 +      if (ptr && decorate) {
 +        *dest = '[';
 +        memcpy(dest+strlen(dest), "]", 2);
 +        tor_assert(ptr == dest+1);
 +        ptr = dest;
 +      }
 +      break;
 +    case AF_UNIX:
 +      tor_snprintf(dest, len, "AF_UNIX");
 +      ptr = dest;
 +      break;
 +    default:
 +      return NULL;
 +  }
 +  return ptr;
 +}
 +
 +/** Parse an .in-addr.arpa or .ip6.arpa address from <b>address</b>.  Return 0
 + * if this is not an .in-addr.arpa address or an .ip6.arpa address.  Return -1
 + * if this is an ill-formed .in-addr.arpa address or an .ip6.arpa address.
 + * Also return -1 if <b>family</b> is not AF_UNSPEC, and the parsed address
 + * family does not match <b>family</b>.  On success, return 1, and store the
 + * result, if any, into <b>result</b>, if provided.
 + *
 + * If <b>accept_regular</b> is set and the address is in neither recognized
 + * reverse lookup hostname format, try parsing the address as a regular
 + * IPv4 or IPv6 address too.
 + */
 +int
 +tor_addr_parse_PTR_name(tor_addr_t *result, const char *address,
 +                                   int family, int accept_regular)
 +{
 +  if (!strcasecmpend(address, ".in-addr.arpa")) {
 +    /* We have an in-addr.arpa address. */
 +    char buf[INET_NTOA_BUF_LEN];
 +    size_t len;
 +    struct in_addr inaddr;
 +    if (family == AF_INET6)
 +      return -1;
 +
 +    len = strlen(address) - strlen(".in-addr.arpa");
 +    if (len >= INET_NTOA_BUF_LEN)
 +      return -1; /* Too long. */
 +
 +    memcpy(buf, address, len);
 +    buf[len] = '\0';
 +    if (tor_inet_aton(buf, &inaddr) == 0)
 +      return -1; /* malformed. */
 +
 +    /* reverse the bytes */
 +    inaddr.s_addr = (uint32_t)
 +      (((inaddr.s_addr & 0x000000ff) << 24)
 +       |((inaddr.s_addr & 0x0000ff00) << 8)
 +       |((inaddr.s_addr & 0x00ff0000) >> 8)
 +       |((inaddr.s_addr & 0xff000000) >> 24));
 +
 +    if (result) {
 +      tor_addr_from_in(result, &inaddr);
 +    }
 +    return 1;
 +  }
 +
 +  if (!strcasecmpend(address, ".ip6.arpa")) {
 +    const char *cp;
 +    int n0, n1;
 +    struct in6_addr in6;
 +
 +    if (family == AF_INET)
 +      return -1;
 +
 +    cp = address;
 +    for (int i = 0; i < 16; ++i) {
 +      n0 = hex_decode_digit(*cp++); /* The low-order nybble appears first. */
 +      if (*cp++ != '.') return -1;  /* Then a dot. */
 +      n1 = hex_decode_digit(*cp++); /* The high-order nybble appears first. */
 +      if (*cp++ != '.') return -1;  /* Then another dot. */
 +      if (n0<0 || n1 < 0) /* Both nybbles must be hex. */
 +        return -1;
 +
 +      /* We don't check the length of the string in here.  But that's okay,
 +       * since we already know that the string ends with ".ip6.arpa", and
 +       * there is no way to frameshift .ip6.arpa so it fits into the pattern
 +       * of hexdigit, period, hexdigit, period that we enforce above.
 +       */
 +
 +      /* Assign from low-byte to high-byte. */
 +      in6.s6_addr[15-i] = n0 | (n1 << 4);
 +    }
 +    if (strcasecmp(cp, "ip6.arpa"))
 +      return -1;
 +
 +    if (result) {
 +      tor_addr_from_in6(result, &in6);
 +    }
 +    return 1;
 +  }
 +
 +  if (accept_regular) {
 +    tor_addr_t tmp;
 +    int r = tor_addr_parse(&tmp, address);
 +    if (r < 0)
 +      return 0;
 +    if (r != family && family != AF_UNSPEC)
 +      return -1;
 +
 +    if (result)
 +      memcpy(result, &tmp, sizeof(tor_addr_t));
 +
 +    return 1;
 +  }
 +
 +  return 0;
 +}
 +
 +/** Convert <b>addr</b> to an in-addr.arpa name or a .ip6.arpa name,
 + * and store the result in the <b>outlen</b>-byte buffer at
 + * <b>out</b>.  Returns a non-negative integer on success.
 + * Returns -1 on failure. */
 +int
 +tor_addr_to_PTR_name(char *out, size_t outlen,
 +                     const tor_addr_t *addr)
 +{
 +  tor_assert(out);
 +  tor_assert(addr);
 +
 +  if (addr->family == AF_INET) {
 +    uint32_t a = tor_addr_to_ipv4h(addr);
 +
 +    return tor_snprintf(out, outlen, "%d.%d.%d.%d.in-addr.arpa",
 +                        (int)(uint8_t)((a    )&0xff),
 +                        (int)(uint8_t)((a>>8 )&0xff),
 +                        (int)(uint8_t)((a>>16)&0xff),
 +                        (int)(uint8_t)((a>>24)&0xff));
 +  } else if (addr->family == AF_INET6) {
 +    int i;
 +    char *cp = out;
 +    const uint8_t *bytes = tor_addr_to_in6_addr8(addr);
 +    if (outlen < REVERSE_LOOKUP_NAME_BUF_LEN)
 +      return -1;
 +    for (i = 15; i >= 0; --i) {
 +      uint8_t byte = bytes[i];
 +      *cp++ = "0123456789abcdef"[byte & 0x0f];
 +      *cp++ = '.';
 +      *cp++ = "0123456789abcdef"[byte >> 4];
 +      *cp++ = '.';
 +    }
 +    memcpy(cp, "ip6.arpa", 9); /* 8 characters plus NUL */
 +    return 32 * 2 + 8;
 +  }
 +  return -1;
 +}
 +
 +/** Parse a string <b>s</b> containing an IPv4/IPv6 address, and possibly
 + *  a mask and port or port range.  Store the parsed address in
 + *  <b>addr_out</b>, a mask (if any) in <b>mask_out</b>, and port(s) (if any)
 + *  in <b>port_min_out</b> and <b>port_max_out</b>.
 + *
 + * The syntax is:
 + *   Address OptMask OptPortRange
 + *   Address ::= IPv4Address / "[" IPv6Address "]" / "*"
 + *   OptMask ::= "/" Integer /
 + *   OptPortRange ::= ":*" / ":" Integer / ":" Integer "-" Integer /
 + *
 + *  - If mask, minport, or maxport are NULL, we do not want these
 + *    options to be set; treat them as an error if present.
 + *  - If the string has no mask, the mask is set to /32 (IPv4) or /128 (IPv6).
 + *  - If the string has one port, it is placed in both min and max port
 + *    variables.
 + *  - If the string has no port(s), port_(min|max)_out are set to 1 and 65535.
 + *
 + *  Return an address family on success, or -1 if an invalid address string is
 + *  provided.
 + *
 + *  If 'flags & TAPMP_EXTENDED_STAR' is false, then the wildcard address '*'
 + *  yield an IPv4 wildcard.
 + *
 + *  If 'flags & TAPMP_EXTENDED_STAR' is true, then the wildcard address '*'
 + *  yields an AF_UNSPEC wildcard address, which expands to corresponding
 + *  wildcard IPv4 and IPv6 rules, and the following change is made
 + *  in the grammar above:
 + *   Address ::= IPv4Address / "[" IPv6Address "]" / "*" / "*4" / "*6"
 + *  with the new "*4" and "*6" productions creating a wildcard to match
 + *  IPv4 or IPv6 addresses.
 + *
 + *  If 'flags & TAPMP_EXTENDED_STAR' and 'flags & TAPMP_STAR_IPV4_ONLY' are
 + *  both true, then the wildcard address '*' yields an IPv4 wildcard.
 + *
 + *  If 'flags & TAPMP_EXTENDED_STAR' and 'flags & TAPMP_STAR_IPV6_ONLY' are
 + *  both true, then the wildcard address '*' yields an IPv6 wildcard.
 + *
 + * TAPMP_STAR_IPV4_ONLY and TAPMP_STAR_IPV6_ONLY are mutually exclusive. */
 +int
 +tor_addr_parse_mask_ports(const char *s,
 +                          unsigned flags,
 +                          tor_addr_t *addr_out,
 +                          maskbits_t *maskbits_out,
 +                          uint16_t *port_min_out, uint16_t *port_max_out)
 +{
 +  char *base = NULL, *address, *mask = NULL, *port = NULL, *rbracket = NULL;
 +  char *endptr;
 +  int any_flag=0, v4map=0;
 +  sa_family_t family;
 +  struct in6_addr in6_tmp;
 +  struct in_addr in_tmp = { .s_addr = 0 };
 +
 +  tor_assert(s);
 +  tor_assert(addr_out);
 +  /* We can either only want an IPv4 address or only want an IPv6 address,
 +   * but we can't only want IPv4 & IPv6 at the same time. */
 +  tor_assert(!((flags & TAPMP_STAR_IPV4_ONLY)
 +               && (flags & TAPMP_STAR_IPV6_ONLY)));
 +
 +  /** Longest possible length for an address, mask, and port-range combination.
 +   * Includes IP, [], /mask, :, ports */
 +#define MAX_ADDRESS_LENGTH (TOR_ADDR_BUF_LEN+2+(1+INET_NTOA_BUF_LEN)+12+1)
 +
 +  if (strlen(s) > MAX_ADDRESS_LENGTH) {
 +    log_warn(LD_GENERAL, "Impossibly long IP %s; rejecting", escaped(s));
 +    goto err;
 +  }
 +  base = tor_strdup(s);
 +
 +  /* Break 'base' into separate strings. */
 +  address = base;
 +  if (*address == '[') {  /* Probably IPv6 */
 +    address++;
 +    rbracket = strchr(address, ']');
 +    if (!rbracket) {
 +      log_warn(LD_GENERAL,
 +               "No closing IPv6 bracket in address pattern; rejecting.");
 +      goto err;
 +    }
 +  }
 +  mask = strchr((rbracket?rbracket:address),'/');
 +  port = strchr((mask?mask:(rbracket?rbracket:address)), ':');
 +  if (port)
 +    *port++ = '\0';
 +  if (mask)
 +    *mask++ = '\0';
 +  if (rbracket)
 +    *rbracket = '\0';
 +  if (port && mask)
 +    tor_assert(port > mask);
 +  if (mask && rbracket)
 +    tor_assert(mask > rbracket);
 +
 +  /* Now "address" is the a.b.c.d|'*'|abcd::1 part...
 +   *     "mask" is the Mask|Maskbits part...
 +   * and "port" is the *|port|min-max part.
 +   */
 +
 +  /* Process the address portion */
 +  memset(addr_out, 0, sizeof(tor_addr_t));
 +
 +  if (!strcmp(address, "*")) {
 +    if (flags & TAPMP_EXTENDED_STAR) {
 +      if (flags & TAPMP_STAR_IPV4_ONLY) {
 +        family = AF_INET;
 +        tor_addr_from_ipv4h(addr_out, 0);
 +      } else if (flags & TAPMP_STAR_IPV6_ONLY) {
 +        static char nil_bytes[16] = { [0]=0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0 };
 +        family = AF_INET6;
 +        tor_addr_from_ipv6_bytes(addr_out, nil_bytes);
 +      } else {
 +        family = AF_UNSPEC;
 +        tor_addr_make_unspec(addr_out);
 +        log_info(LD_GENERAL,
 +                 "'%s' expands into rules which apply to all IPv4 and IPv6 "
 +                 "addresses. (Use accept/reject *4:* for IPv4 or "
 +                 "accept[6]/reject[6] *6:* for IPv6.)", s);
 +      }
 +    } else {
 +      family = AF_INET;
 +      tor_addr_from_ipv4h(addr_out, 0);
 +    }
 +    any_flag = 1;
 +  } else if (!strcmp(address, "*4") && (flags & TAPMP_EXTENDED_STAR)) {
 +    family = AF_INET;
 +    tor_addr_from_ipv4h(addr_out, 0);
 +    any_flag = 1;
 +  } else if (!strcmp(address, "*6") && (flags & TAPMP_EXTENDED_STAR)) {
 +    static char nil_bytes[16] = { [0]=0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0 };
 +    family = AF_INET6;
 +    tor_addr_from_ipv6_bytes(addr_out, nil_bytes);
 +    any_flag = 1;
 +  } else if (tor_inet_pton(AF_INET6, address, &in6_tmp) > 0) {
 +    family = AF_INET6;
 +    tor_addr_from_in6(addr_out, &in6_tmp);
 +  } else if (tor_inet_pton(AF_INET, address, &in_tmp) > 0) {
 +    family = AF_INET;
 +    tor_addr_from_in(addr_out, &in_tmp);
 +  } else {
 +    log_warn(LD_GENERAL, "Malformed IP %s in address pattern; rejecting.",
 +             escaped(address));
 +    goto err;
 +  }
 +
 +  v4map = tor_addr_is_v4(addr_out);
 +
 +  /* Parse mask */
 +  if (maskbits_out) {
 +    int bits = 0;
 +    struct in_addr v4mask;
 +
 +    if (mask) {  /* the caller (tried to) specify a mask */
 +      bits = (int) strtol(mask, &endptr, 10);
 +      if (!*endptr) {  /* strtol converted everything, so it was an integer */
 +        if ((bits<0 || bits>128) ||
 +            (family == AF_INET && bits > 32)) {
 +          log_warn(LD_GENERAL,
 +                   "Bad number of mask bits (%d) on address range; rejecting.",
 +                   bits);
 +          goto err;
 +        }
 +      } else {  /* mask might still be an address-style mask */
 +        if (tor_inet_pton(AF_INET, mask, &v4mask) > 0) {
 +          bits = addr_mask_get_bits(ntohl(v4mask.s_addr));
 +          if (bits < 0) {
 +            log_warn(LD_GENERAL,
 +                     "IPv4-style mask %s is not a prefix address; rejecting.",
 +                     escaped(mask));
 +            goto err;
 +          }
 +        } else { /* Not IPv4; we don't do address-style IPv6 masks. */
 +          log_warn(LD_GENERAL,
 +                   "Malformed mask on address range %s; rejecting.",
 +                   escaped(s));
 +          goto err;
 +        }
 +      }
 +      if (family == AF_INET6 && v4map) {
 +        if (bits > 32 && bits < 96) { /* Crazy */
 +          log_warn(LD_GENERAL,
 +                   "Bad mask bits %d for V4-mapped V6 address; rejecting.",
 +                   bits);
 +          goto err;
 +        }
 +        /* XXXX_IP6 is this really what we want? */
 +        bits = 96 + bits%32; /* map v4-mapped masks onto 96-128 bits */
 +      }
 +      if (any_flag) {
 +        log_warn(LD_GENERAL,
 +                 "Found bit prefix with wildcard address; rejecting");
 +        goto err;
 +      }
 +    } else { /* pick an appropriate mask, as none was given */
 +      if (any_flag)
 +        bits = 0;  /* This is okay whether it's V6 or V4 (FIX V4-mapped V6!) */
 +      else if (tor_addr_family(addr_out) == AF_INET)
 +        bits = 32;
 +      else if (tor_addr_family(addr_out) == AF_INET6)
 +        bits = 128;
 +    }
 +    *maskbits_out = (maskbits_t) bits;
 +  } else {
 +    if (mask) {
 +      log_warn(LD_GENERAL,
 +               "Unexpected mask in address %s; rejecting", escaped(s));
 +      goto err;
 +    }
 +  }
 +
 +  /* Parse port(s) */
 +  if (port_min_out) {
 +    uint16_t port2;
 +    if (!port_max_out) /* caller specified one port; fake the second one */
 +      port_max_out = &port2;
 +
 +    if (parse_port_range(port, port_min_out, port_max_out) < 0) {
 +      goto err;
 +    } else if ((*port_min_out != *port_max_out) && port_max_out == &port2) {
 +      log_warn(LD_GENERAL,
 +               "Wanted one port from address range, but there are two.");
 +
 +      port_max_out = NULL;  /* caller specified one port, so set this back */
 +      goto err;
 +    }
 +  } else {
 +    if (port) {
 +      log_warn(LD_GENERAL,
 +               "Unexpected ports in address %s; rejecting", escaped(s));
 +      goto err;
 +    }
 +  }
 +
 +  tor_free(base);
 +  return tor_addr_family(addr_out);
 + err:
 +  tor_free(base);
 +  return -1;
 +}
 +
 +/** Determine whether an address is IPv4, either native or IPv4-mapped IPv6.
 + * Note that this is about representation only, as any decent stack will
 + * reject IPv4-mapped addresses received on the wire (and won't use them
 + * on the wire either).
 + */
 +int
 +tor_addr_is_v4(const tor_addr_t *addr)
 +{
 +  tor_assert(addr);
 +
 +  if (tor_addr_family(addr) == AF_INET)
 +    return 1;
 +
 +  if (tor_addr_family(addr) == AF_INET6) {
 +    /* First two don't need to be ordered */
 +    uint32_t *a32 = tor_addr_to_in6_addr32(addr);
 +    if (a32[0] == 0 && a32[1] == 0 && ntohl(a32[2]) == 0x0000ffffu)
 +      return 1;
 +  }
 +
 +  return 0; /* Not IPv4 - unknown family or a full-blood IPv6 address */
 +}
 +
 +/** Determine whether an address <b>addr</b> is null, either all zeroes or
 + *  belonging to family AF_UNSPEC.
 + */
 +int
 +tor_addr_is_null(const tor_addr_t *addr)
 +{
 +  tor_assert(addr);
 +
 +  switch (tor_addr_family(addr)) {
 +    case AF_INET6: {
 +      uint32_t *a32 = tor_addr_to_in6_addr32(addr);
 +      return (a32[0] == 0) && (a32[1] == 0) && (a32[2] == 0) && (a32[3] == 0);
 +    }
 +    case AF_INET:
 +      return (tor_addr_to_ipv4n(addr) == 0);
 +    case AF_UNIX:
 +      return 1;
 +    case AF_UNSPEC:
 +      return 1;
 +    default:
 +      log_warn(LD_BUG, "Called with unknown address family %d",
 +               (int)tor_addr_family(addr));
 +      return 0;
 +  }
 +  //return 1;
 +}
 +
 +/** Return true iff <b>addr</b> is a loopback address */
 +int
 +tor_addr_is_loopback(const tor_addr_t *addr)
 +{
 +  tor_assert(addr);
 +  switch (tor_addr_family(addr)) {
 +    case AF_INET6: {
 +      /* ::1 */
 +      uint32_t *a32 = tor_addr_to_in6_addr32(addr);
 +      return (a32[0] == 0) && (a32[1] == 0) && (a32[2] == 0) &&
 +        (ntohl(a32[3]) == 1);
 +    }
 +    case AF_INET:
 +      /* 127.0.0.1 */
 +      return (tor_addr_to_ipv4h(addr) & 0xff000000) == 0x7f000000;
 +    case AF_UNSPEC:
 +      return 0;
 +      /* LCOV_EXCL_START */
 +    default:
 +      tor_fragile_assert();
 +      return 0;
 +      /* LCOV_EXCL_STOP */
 +  }
 +}
 +
 +/* Is addr valid?
 + * Checks that addr is non-NULL and not tor_addr_is_null().
 + * If for_listening is true, IPv4 addr 0.0.0.0 is allowed.
 + * It means "bind to all addresses on the local machine". */
 +int
 +tor_addr_is_valid(const tor_addr_t *addr, int for_listening)
 +{
 +  /* NULL addresses are invalid regardless of for_listening */
 +  if (addr == NULL) {
 +    return 0;
 +  }
 +
 +  /* Only allow IPv4 0.0.0.0 for_listening. */
 +  if (for_listening && addr->family == AF_INET
 +      && tor_addr_to_ipv4h(addr) == 0) {
 +    return 1;
 +  }
 +
 +  /* Otherwise, the address is valid if it's not tor_addr_is_null() */
 +  return !tor_addr_is_null(addr);
 +}
 +
 +/* Is the network-order IPv4 address v4n_addr valid?
 + * Checks that addr is not zero.
 + * Except if for_listening is true, where IPv4 addr 0.0.0.0 is allowed. */
 +int
 +tor_addr_is_valid_ipv4n(uint32_t v4n_addr, int for_listening)
 +{
 +  /* Any IPv4 address is valid with for_listening. */
 +  if (for_listening) {
 +    return 1;
 +  }
 +
 +  /* Otherwise, zero addresses are invalid. */
 +  return v4n_addr != 0;
 +}
 +
 +/* Is port valid?
 + * Checks that port is not 0.
 + * Except if for_listening is true, where port 0 is allowed.
 + * It means "OS chooses a port". */
 +int
 +tor_port_is_valid(uint16_t port, int for_listening)
 +{
 +  /* Any port value is valid with for_listening. */
 +  if (for_listening) {
 +    return 1;
 +  }
 +
 +  /* Otherwise, zero ports are invalid. */
 +  return port != 0;
 +}
 +
 +/** Set <b>dest</b> to equal the IPv4 address in <b>v4addr</b> (given in
 + * network order). */
 +void
 +tor_addr_from_ipv4n(tor_addr_t *dest, uint32_t v4addr)
 +{
 +  tor_assert(dest);
 +  memset(dest, 0, sizeof(tor_addr_t));
 +  dest->family = AF_INET;
 +  dest->addr.in_addr.s_addr = v4addr;
 +}
 +
 +/** Set <b>dest</b> to equal the IPv6 address in the 16 bytes at
 + * <b>ipv6_bytes</b>. */
 +void
 +tor_addr_from_ipv6_bytes(tor_addr_t *dest, const char *ipv6_bytes)
 +{
 +  tor_assert(dest);
 +  tor_assert(ipv6_bytes);
 +  memset(dest, 0, sizeof(tor_addr_t));
 +  dest->family = AF_INET6;
 +  memcpy(dest->addr.in6_addr.s6_addr, ipv6_bytes, 16);
 +}
 +
 +/** Set <b>dest</b> equal to the IPv6 address in the in6_addr <b>in6</b>. */
 +void
 +tor_addr_from_in6(tor_addr_t *dest, const struct in6_addr *in6)
 +{
 +  tor_addr_from_ipv6_bytes(dest, (const char*)in6->s6_addr);
 +}
 +
 +/** Copy a tor_addr_t from <b>src</b> to <b>dest</b>.
 + */
 +void
 +tor_addr_copy(tor_addr_t *dest, const tor_addr_t *src)
 +{
 +  if (src == dest)
 +    return;
 +  tor_assert(src);
 +  tor_assert(dest);
 +  memcpy(dest, src, sizeof(tor_addr_t));
 +}
 +
 +/** Copy a tor_addr_t from <b>src</b> to <b>dest</b>, taking extra care to
 + * copy only the well-defined portions. Used for computing hashes of
 + * addresses.
 + */
 +void
 +tor_addr_copy_tight(tor_addr_t *dest, const tor_addr_t *src)
 +{
 +  tor_assert(src != dest);
 +  tor_assert(src);
 +  tor_assert(dest);
 +  memset(dest, 0, sizeof(tor_addr_t));
 +  dest->family = src->family;
 +  switch (tor_addr_family(src))
 +    {
 +    case AF_INET:
 +      dest->addr.in_addr.s_addr = src->addr.in_addr.s_addr;
 +      break;
 +    case AF_INET6:
 +      memcpy(dest->addr.in6_addr.s6_addr, src->addr.in6_addr.s6_addr, 16);
 +    case AF_UNSPEC:
 +      break;
 +      // LCOV_EXCL_START
 +    default:
 +      tor_fragile_assert();
 +      // LCOV_EXCL_STOP
 +    }
 +}
 +
 +/** Given two addresses <b>addr1</b> and <b>addr2</b>, return 0 if the two
 + * addresses are equivalent under the mask mbits, less than 0 if addr1
 + * precedes addr2, and greater than 0 otherwise.
 + *
 + * Different address families (IPv4 vs IPv6) are always considered unequal if
 + * <b>how</b> is CMP_EXACT; otherwise, IPv6-mapped IPv4 addresses are
 + * considered equivalent to their IPv4 equivalents.
 + *
 + * As a special case, all pointer-wise distinct AF_UNIX addresses are always
 + * considered unequal since tor_addr_t currently does not contain the
 + * information required to make the comparison.
 + */
 +int
 +tor_addr_compare(const tor_addr_t *addr1, const tor_addr_t *addr2,
 +                 tor_addr_comparison_t how)
 +{
 +  return tor_addr_compare_masked(addr1, addr2, 128, how);
 +}
 +
 +/** As tor_addr_compare(), but only looks at the first <b>mask</b> bits of
 + * the address.
 + *
 + * Reduce over-specific masks (>128 for ipv6, >32 for ipv4) to 128 or 32.
 + *
 + * The mask is interpreted relative to <b>addr1</b>, so that if a is
 + * \::ffff:1.2.3.4, and b is 3.4.5.6,
 + * tor_addr_compare_masked(a,b,100,CMP_SEMANTIC) is the same as
 + * -tor_addr_compare_masked(b,a,4,CMP_SEMANTIC).
 + *
 + * We guarantee that the ordering from tor_addr_compare_masked is a total
 + * order on addresses, but not that it is any particular order, or that it
 + * will be the same from one version to the next.
 + */
 +int
 +tor_addr_compare_masked(const tor_addr_t *addr1, const tor_addr_t *addr2,
 +                        maskbits_t mbits, tor_addr_comparison_t how)
 +{
 +  /** Helper: Evaluates to -1 if a is less than b, 0 if a equals b, or 1 if a
 +   * is greater than b.  May evaluate a and b more than once.  */
 +#define TRISTATE(a,b) (((a)<(b))?-1: (((a)==(b))?0:1))
 +  sa_family_t family1, family2, v_family1, v_family2;
 +
 +  tor_assert(addr1 && addr2);
 +
 +  v_family1 = family1 = tor_addr_family(addr1);
 +  v_family2 = family2 = tor_addr_family(addr2);
 +
 +  if (family1==family2) {
 +    /* When the families are the same, there's only one way to do the
 +     * comparison: exactly. */
 +    int r;
 +    switch (family1) {
 +      case AF_UNSPEC:
 +        return 0; /* All unspecified addresses are equal */
 +      case AF_INET: {
 +        uint32_t a1 = tor_addr_to_ipv4h(addr1);
 +        uint32_t a2 = tor_addr_to_ipv4h(addr2);
 +        if (mbits <= 0)
 +          return 0;
 +        if (mbits > 32)
 +          mbits = 32;
 +        a1 >>= (32-mbits);
 +        a2 >>= (32-mbits);
 +        r = TRISTATE(a1, a2);
 +        return r;
 +      }
 +      case AF_INET6: {
 +        if (mbits > 128)
 +          mbits = 128;
 +
 +        const uint8_t *a1 = tor_addr_to_in6_addr8(addr1);
 +        const uint8_t *a2 = tor_addr_to_in6_addr8(addr2);
 +        const int bytes = mbits >> 3;
 +        const int leftover_bits = mbits & 7;
 +        if (bytes && (r = tor_memcmp(a1, a2, bytes))) {
 +          return r;
 +        } else if (leftover_bits) {
 +          uint8_t b1 = a1[bytes] >> (8-leftover_bits);
 +          uint8_t b2 = a2[bytes] >> (8-leftover_bits);
 +          return TRISTATE(b1, b2);
 +        } else {
 +          return 0;
 +        }
 +      }
 +      case AF_UNIX:
 +        /* HACKHACKHACKHACKHACK:
 +         * tor_addr_t doesn't contain a copy of sun_path, so it's not
 +         * possible to compare this at all.
 +         *
 +         * Since the only time we currently actually should be comparing
 +         * 2 AF_UNIX addresses is when dealing with ISO_CLIENTADDR (which
 +         * is disabled for AF_UNIX SocksPorts anyway), this just does
 +         * a pointer comparison.
 +         *
 +         * See: #20261.
 +         */
 +        if (addr1 < addr2)
 +          return -1;
 +        else if (addr1 == addr2)
 +          return 0;
 +        else
 +          return 1;
 +        /* LCOV_EXCL_START */
 +      default:
 +        tor_fragile_assert();
 +        return 0;
 +        /* LCOV_EXCL_STOP */
 +    }
 +  } else if (how == CMP_EXACT) {
 +    /* Unequal families and an exact comparison?  Stop now! */
 +    return TRISTATE(family1, family2);
 +  }
 +
 +  if (mbits == 0)
 +    return 0;
 +
 +  if (family1 == AF_INET6 && tor_addr_is_v4(addr1))
 +    v_family1 = AF_INET;
 +  if (family2 == AF_INET6 && tor_addr_is_v4(addr2))
 +    v_family2 = AF_INET;
 +  if (v_family1 == v_family2) {
 +    /* One or both addresses are a mapped ipv4 address. */
 +    uint32_t a1, a2;
 +    if (family1 == AF_INET6) {
 +      a1 = tor_addr_to_mapped_ipv4h(addr1);
 +      if (mbits <= 96)
 +        return 0;
 +      mbits -= 96; /* We just decided that the first 96 bits of a1 "match". */
 +    } else {
 +      a1 = tor_addr_to_ipv4h(addr1);
 +    }
 +    if (family2 == AF_INET6) {
 +      a2 = tor_addr_to_mapped_ipv4h(addr2);
 +    } else {
 +      a2 = tor_addr_to_ipv4h(addr2);
 +    }
 +    if (mbits > 32) mbits = 32;
 +    a1 >>= (32-mbits);
 +    a2 >>= (32-mbits);
 +    return TRISTATE(a1, a2);
 +  } else {
 +    /* Unequal families, and semantic comparison, and no semantic family
 +     * matches. */
 +    return TRISTATE(family1, family2);
 +  }
 +}
 +
 +/** Input for siphash, to produce some output for an unspec value. */
 +static const uint32_t unspec_hash_input[] = { 0x4e4df09f, 0x92985342 };
 +
 +/** Return a hash code based on the address addr. DOCDOC extra */
 +uint64_t
 +tor_addr_hash(const tor_addr_t *addr)
 +{
 +  switch (tor_addr_family(addr)) {
 +  case AF_INET:
 +    return siphash24g(&addr->addr.in_addr.s_addr, 4);
 +  case AF_UNSPEC:
 +    return siphash24g(unspec_hash_input, sizeof(unspec_hash_input));
 +  case AF_INET6:
 +    return siphash24g(&addr->addr.in6_addr.s6_addr, 16);
 +    /* LCOV_EXCL_START */
 +  default:
 +    tor_fragile_assert();
 +    return 0;
 +    /* LCOV_EXCL_STOP */
 +  }
 +}
 +
 +/** As tor_addr_hash, but use a particular siphash key. */
 +uint64_t
 +tor_addr_keyed_hash(const struct sipkey *key, const tor_addr_t *addr)
 +{
 +  /* This is duplicate code with tor_addr_hash, since this function needs to
 +   * be backportable all the way to 0.2.9. */
 +
 +  switch (tor_addr_family(addr)) {
 +  case AF_INET:
 +    return siphash24(&addr->addr.in_addr.s_addr, 4, key);
 +  case AF_UNSPEC:
 +    return siphash24(unspec_hash_input, sizeof(unspec_hash_input), key);
 +  case AF_INET6:
 +    return siphash24(&addr->addr.in6_addr.s6_addr, 16, key);
 +  default:
 +    /* LCOV_EXCL_START */
 +    tor_fragile_assert();
 +    return 0;
 +    /* LCOV_EXCL_STOP */
 +  }
 +}
 +
 +/** Return a newly allocated string with a representation of <b>addr</b>. */
 +char *
 +tor_addr_to_str_dup(const tor_addr_t *addr)
 +{
 +  char buf[TOR_ADDR_BUF_LEN];
 +  if (tor_addr_to_str(buf, addr, sizeof(buf), 0)) {
 +    return tor_strdup(buf);
 +  } else {
 +    return tor_strdup("<unknown address type>");
 +  }
 +}
 +
 +/** Return a string representing the address <b>addr</b>.  This string
 + * is statically allocated, and must not be freed.  Each call to
 + * <b>fmt_addr_impl</b> invalidates the last result of the function.
 + * This function is not thread-safe. If <b>decorate</b> is set, add
 + * brackets to IPv6 addresses.
 + *
 + * It's better to use the wrapper macros of this function:
 + * <b>fmt_addr()</b> and <b>fmt_and_decorate_addr()</b>.
 + */
 +const char *
 +fmt_addr_impl(const tor_addr_t *addr, int decorate)
 +{
 +  static char buf[TOR_ADDR_BUF_LEN];
 +  if (!addr) return "<null>";
 +  if (tor_addr_to_str(buf, addr, sizeof(buf), decorate))
 +    return buf;
 +  else
 +    return "???";
 +}
 +
 +/** Return a string representing the pair <b>addr</b> and <b>port</b>.
 + * This calls fmt_and_decorate_addr internally, so IPv6 addresses will
 + * have brackets, and the caveats of fmt_addr_impl apply.
 + */
 +const char *
 +fmt_addrport(const tor_addr_t *addr, uint16_t port)
 +{
 +  /* Add space for a colon and up to 5 digits. */
 +  static char buf[TOR_ADDR_BUF_LEN + 6];
 +  tor_snprintf(buf, sizeof(buf), "%s:%u", fmt_and_decorate_addr(addr), port);
 +  return buf;
 +}
 +
 +/** Like fmt_addr(), but takes <b>addr</b> as a host-order IPv4
 + * addresses. Also not thread-safe, also clobbers its return buffer on
 + * repeated calls. */
 +const char *
 +fmt_addr32(uint32_t addr)
 +{
 +  static char buf[INET_NTOA_BUF_LEN];
 +  struct in_addr in;
 +  in.s_addr = htonl(addr);
 +  tor_inet_ntoa(&in, buf, sizeof(buf));
 +  return buf;
 +}
 +
 +/** Convert the string in <b>src</b> to a tor_addr_t <b>addr</b>.  The string
 + * may be an IPv4 address, an IPv6 address, or an IPv6 address surrounded by
 + * square brackets.
 + *
 + *  Return an address family on success, or -1 if an invalid address string is
 + *  provided. */
 +int
 +tor_addr_parse(tor_addr_t *addr, const char *src)
 +{
 +  /* Holds substring of IPv6 address after removing square brackets */
 +  char *tmp = NULL;
 +  int result;
 +  struct in_addr in_tmp;
 +  struct in6_addr in6_tmp;
 +  tor_assert(addr && src);
 +  if (src[0] == '[' && src[1])
 +    src = tmp = tor_strndup(src+1, strlen(src)-2);
 +
 +  if (tor_inet_pton(AF_INET6, src, &in6_tmp) > 0) {
 +    result = AF_INET6;
 +    tor_addr_from_in6(addr, &in6_tmp);
 +  } else if (tor_inet_pton(AF_INET, src, &in_tmp) > 0) {
 +    result = AF_INET;
 +    tor_addr_from_in(addr, &in_tmp);
 +  } else {
 +    result = -1;
 +  }
 +
 +  tor_free(tmp);
 +  return result;
 +}
 +
 +#ifdef HAVE_IFADDRS_TO_SMARTLIST
 +/*
 + * Convert a linked list consisting of <b>ifaddrs</b> structures
 + * into smartlist of <b>tor_addr_t</b> structures.
 + */
 +STATIC smartlist_t *
 +ifaddrs_to_smartlist(const struct ifaddrs *ifa, sa_family_t family)
 +{
 +  smartlist_t *result = smartlist_new();
 +  const struct ifaddrs *i;
 +
 +  for (i = ifa; i; i = i->ifa_next) {
 +    tor_addr_t tmp;
 +    if ((i->ifa_flags & (IFF_UP | IFF_RUNNING)) != (IFF_UP | IFF_RUNNING))
 +      continue;
 +    if (!i->ifa_addr)
 +      continue;
 +    if (i->ifa_addr->sa_family != AF_INET &&
 +        i->ifa_addr->sa_family != AF_INET6)
 +      continue;
 +    if (family != AF_UNSPEC && i->ifa_addr->sa_family != family)
 +      continue;
 +    if (tor_addr_from_sockaddr(&tmp, i->ifa_addr, NULL) < 0)
 +      continue;
 +    smartlist_add(result, tor_memdup(&tmp, sizeof(tmp)));
 +  }
 +
 +  return result;
 +}
 +
 +/** Use getiffaddrs() function to get list of current machine
 + * network interface addresses. Represent the result by smartlist of
 + * <b>tor_addr_t</b> structures.
 + */
 +STATIC smartlist_t *
 +get_interface_addresses_ifaddrs(int severity, sa_family_t family)
 +{
 +
 +  /* Most free Unixy systems provide getifaddrs, which gives us a linked list
 +   * of struct ifaddrs. */
 +  struct ifaddrs *ifa = NULL;
 +  smartlist_t *result;
 +  if (getifaddrs(&ifa) < 0) {
 +    log_fn(severity, LD_NET, "Unable to call getifaddrs(): %s",
 +           strerror(errno));
 +    return NULL;
 +  }
 +
 +  result = ifaddrs_to_smartlist(ifa, family);
 +
 +  freeifaddrs(ifa);
 +
 +  return result;
 +}
 +#endif /* defined(HAVE_IFADDRS_TO_SMARTLIST) */
 +
 +#ifdef HAVE_IP_ADAPTER_TO_SMARTLIST
 +
 +/** Convert a Windows-specific <b>addresses</b> linked list into smartlist
 + * of <b>tor_addr_t</b> structures.
 + */
 +
 +STATIC smartlist_t *
 +ip_adapter_addresses_to_smartlist(const IP_ADAPTER_ADDRESSES *addresses)
 +{
 +  smartlist_t *result = smartlist_new();
 +  const IP_ADAPTER_ADDRESSES *address;
 +
 +  for (address = addresses; address; address = address->Next) {
 +    const IP_ADAPTER_UNICAST_ADDRESS *a;
 +    for (a = address->FirstUnicastAddress; a; a = a->Next) {
 +      /* Yes, it's a linked list inside a linked list */
 +      const struct sockaddr *sa = a->Address.lpSockaddr;
 +      tor_addr_t tmp;
 +      if (sa->sa_family != AF_INET && sa->sa_family != AF_INET6)
 +        continue;
 +      if (tor_addr_from_sockaddr(&tmp, sa, NULL) < 0)
 +        continue;
 +      smartlist_add(result, tor_memdup(&tmp, sizeof(tmp)));
 +    }
 +  }
 +
 +  return result;
 +}
 +
 +/** Windows only: use GetAdaptersAddresses() to retrieve the network interface
 + * addresses of the current machine.
 + * Returns a smartlist of <b>tor_addr_t</b>  structures.
 + */
 +STATIC smartlist_t *
 +get_interface_addresses_win32(int severity, sa_family_t family)
 +{
 +  smartlist_t *result = NULL;
 +  ULONG size, res;
 +  IP_ADAPTER_ADDRESSES *addresses = NULL;
 +
 +  (void) severity;
 +
 +#define FLAGS (GAA_FLAG_SKIP_ANYCAST | \
 +               GAA_FLAG_SKIP_MULTICAST | \
 +               GAA_FLAG_SKIP_DNS_SERVER)
 +
 +  /* Guess how much space we need. */
 +  size = 15*1024;
 +  addresses = tor_malloc(size);
 +  /* Exists in windows XP and later. */
 +  res = GetAdaptersAddresses(family, FLAGS, NULL, addresses, &size);
 +  if (res == ERROR_BUFFER_OVERFLOW) {
 +    /* we didn't guess that we needed enough space; try again */
 +    tor_free(addresses);
 +    addresses = tor_malloc(size);
 +    res = GetAdaptersAddresses(AF_UNSPEC, FLAGS, NULL, addresses, &size);
 +  }
 +  if (res != NO_ERROR) {
 +    log_fn(severity, LD_NET, "GetAdaptersAddresses failed (result: %lu)", res);
 +    goto done;
 +  }
 +
 +  result = ip_adapter_addresses_to_smartlist(addresses);
 +
 + done:
 +  tor_free(addresses);
 +  return result;
 +}
 +
 +#endif /* defined(HAVE_IP_ADAPTER_TO_SMARTLIST) */
 +
 +#ifdef HAVE_IFCONF_TO_SMARTLIST
 +
 +/* Guess how much space we need. There shouldn't be any struct ifreqs
 + * larger than this, even on OS X where the struct's size is dynamic. */
 +#define IFREQ_SIZE 4096
 +
 +/* This is defined on Mac OS X */
 +#ifndef _SIZEOF_ADDR_IFREQ
 +#define _SIZEOF_ADDR_IFREQ sizeof
 +#endif
 +
 +/* Free ifc->ifc_buf safely. */
 +static void
 +ifconf_free_ifc_buf(struct ifconf *ifc)
 +{
 +  /* On macOS, tor_free() takes the address of ifc.ifc_buf, which leads to
 +   * undefined behaviour, because pointer-to-pointers are expected to be
 +   * aligned at 8-bytes, but the ifconf structure is packed.  So we use
 +   * raw_free() instead. */
 +  raw_free(ifc->ifc_buf);
 +  ifc->ifc_buf = NULL;
 +}
 +
 +/** Convert <b>*buf</b>, an ifreq structure array of size <b>buflen</b>,
 + * into smartlist of <b>tor_addr_t</b> structures.
 + */
 +STATIC smartlist_t *
 +ifreq_to_smartlist(char *buf, size_t buflen)
 +{
 +  smartlist_t *result = smartlist_new();
 +  char *end = buf + buflen;
 +
 +  /* These acrobatics are due to alignment issues which trigger
 +   * undefined behaviour traps on OSX. */
 +  struct ifreq *r = tor_malloc(IFREQ_SIZE);
 +
 +  while (buf < end) {
 +    /* Copy up to IFREQ_SIZE bytes into the struct ifreq, but don't overrun
 +     * buf. */
 +    memcpy(r, buf, end - buf < IFREQ_SIZE ? end - buf : IFREQ_SIZE);
 +
 +    const struct sockaddr *sa = &r->ifr_addr;
 +    tor_addr_t tmp;
 +    int valid_sa_family = (sa->sa_family == AF_INET ||
 +                           sa->sa_family == AF_INET6);
 +
 +    int conversion_success = (tor_addr_from_sockaddr(&tmp, sa, NULL) == 0);
 +
 +    if (valid_sa_family && conversion_success)
 +      smartlist_add(result, tor_memdup(&tmp, sizeof(tmp)));
 +
 +    buf += _SIZEOF_ADDR_IFREQ(*r);
 +  }
 +
 +  tor_free(r);
 +  return result;
 +}
 +
 +/** Use ioctl(.,SIOCGIFCONF,.) to get a list of current machine
 + * network interface addresses. Represent the result by smartlist of
 + * <b>tor_addr_t</b> structures.
 + */
 +STATIC smartlist_t *
 +get_interface_addresses_ioctl(int severity, sa_family_t family)
 +{
 +  /* Some older unixy systems make us use ioctl(SIOCGIFCONF) */
 +  struct ifconf ifc;
 +  ifc.ifc_buf = NULL;
 +  int fd;
 +  smartlist_t *result = NULL;
 +
 +  /* This interface, AFAICT, only supports AF_INET addresses,
 +   * except on AIX. For Solaris, we could use SIOCGLIFCONF. */
 +
 +  /* Bail out if family is neither AF_INET nor AF_UNSPEC since
 +   * ioctl() technique supports non-IPv4 interface addresses on
 +   * a small number of niche systems only. If family is AF_UNSPEC,
 +   * fall back to getting AF_INET addresses only. */
 +  if (family == AF_UNSPEC)
 +    family = AF_INET;
 +  else if (family != AF_INET)
 +    return NULL;
 +
 +  fd = socket(family, SOCK_DGRAM, 0);
 +  if (fd < 0) {
 +    tor_log(severity, LD_NET, "socket failed: %s", strerror(errno));
 +    goto done;
 +  }
 +
 +  int mult = 1;
 +  do {
 +    mult *= 2;
 +    ifc.ifc_len = mult * IFREQ_SIZE;
 +    ifc.ifc_buf = tor_realloc(ifc.ifc_buf, ifc.ifc_len);
 +
 +    tor_assert(ifc.ifc_buf);
 +
 +    if (ioctl(fd, SIOCGIFCONF, &ifc) < 0) {
 +      tor_log(severity, LD_NET, "ioctl failed: %s", strerror(errno));
 +      goto done;
 +    }
 +    /* Ensure we have least IFREQ_SIZE bytes unused at the end. Otherwise, we
 +     * don't know if we got everything during ioctl. */
 +  } while (mult * IFREQ_SIZE - ifc.ifc_len <= IFREQ_SIZE);
 +  result = ifreq_to_smartlist(ifc.ifc_buf, ifc.ifc_len);
 +
 + done:
 +  if (fd >= 0)
 +    close(fd);
 +  ifconf_free_ifc_buf(&ifc);
 +  return result;
 +}
 +#endif /* defined(HAVE_IFCONF_TO_SMARTLIST) */
 +
 +/** Try to ask our network interfaces what addresses they are bound to.
 + * Return a new smartlist of tor_addr_t on success, and NULL on failure.
 + * (An empty smartlist indicates that we successfully learned that we have no
 + * addresses.)  Log failure messages at <b>severity</b>. Only return the
 + * interface addresses of requested <b>family</b> and ignore the addresses
 + * of other address families. */
 +MOCK_IMPL(smartlist_t *,
 +get_interface_addresses_raw,(int severity, sa_family_t family))
 +{
 +  smartlist_t *result = NULL;
 +#if defined(HAVE_IFADDRS_TO_SMARTLIST)
 +  if ((result = get_interface_addresses_ifaddrs(severity, family)))
 +    return result;
 +#endif
 +#if defined(HAVE_IP_ADAPTER_TO_SMARTLIST)
 +  if ((result = get_interface_addresses_win32(severity, family)))
 +    return result;
 +#endif
 +#if defined(HAVE_IFCONF_TO_SMARTLIST)
 +  if ((result = get_interface_addresses_ioctl(severity, family)))
 +    return result;
 +#endif
 +  (void) severity;
 +  (void) result;
 +  return NULL;
 +}
 +
 +/** Return true iff <b>a</b> is a multicast address.  */
 +int
 +tor_addr_is_multicast(const tor_addr_t *a)
 +{
 +  sa_family_t family = tor_addr_family(a);
 +  if (family == AF_INET) {
 +    uint32_t ipv4h = tor_addr_to_ipv4h(a);
 +    if ((ipv4h >> 24) == 0xe0)
 +      return 1; /* Multicast */
 +  } else if (family == AF_INET6) {
 +    const uint8_t *a32 = tor_addr_to_in6_addr8(a);
 +    if (a32[0] == 0xff)
 +      return 1;
 +  }
 +  return 0;
 +}
 +
 +/** Attempt to retrieve IP address of current host by utilizing some
 + * UDP socket trickery. Only look for address of given <b>family</b>
 + * (only AF_INET and AF_INET6 are supported). Set result to *<b>addr</b>.
 + * Return 0 on success, -1 on failure.
 + */
 +MOCK_IMPL(int,
 +get_interface_address6_via_udp_socket_hack,(int severity,
 +                                            sa_family_t family,
 +                                            tor_addr_t *addr))
 +{
 +  struct sockaddr_storage target_addr;
 +  int sock=-1, r=-1;
 +  socklen_t addr_len;
 +
 +  memset(addr, 0, sizeof(tor_addr_t));
 +  memset(&target_addr, 0, sizeof(target_addr));
 +
 +  /* Don't worry: no packets are sent. We just need to use a real address
 +   * on the actual Internet. */
 +  if (family == AF_INET6) {
 +    struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&target_addr;
 +    /* Use the "discard" service port */
 +    sin6->sin6_port = htons(9);
 +    sock = tor_open_socket(PF_INET6,SOCK_DGRAM,IPPROTO_UDP);
 +    addr_len = (socklen_t)sizeof(struct sockaddr_in6);
 +    sin6->sin6_family = AF_INET6;
 +    S6_ADDR16(sin6->sin6_addr)[0] = htons(0x2002); /* 2002:: */
 +  } else if (family == AF_INET) {
 +    struct sockaddr_in *sin = (struct sockaddr_in*)&target_addr;
 +    /* Use the "discard" service port */
 +    sin->sin_port = htons(9);
 +    sock = tor_open_socket(PF_INET,SOCK_DGRAM,IPPROTO_UDP);
 +    addr_len = (socklen_t)sizeof(struct sockaddr_in);
 +    sin->sin_family = AF_INET;
 +    sin->sin_addr.s_addr = htonl(0x12000001); /* 18.0.0.1 */
 +  } else {
 +    return -1;
 +  }
 +
 +  if (sock < 0) {
 +    int e = tor_socket_errno(-1);
 +    log_fn(severity, LD_NET, "unable to create socket: %s",
 +           tor_socket_strerror(e));
 +    goto err;
 +  }
 +
 +  if (tor_connect_socket(sock,(struct sockaddr *)&target_addr,
 +                         addr_len) < 0) {
 +    int e = tor_socket_errno(sock);
 +    log_fn(severity, LD_NET, "connect() failed: %s", tor_socket_strerror(e));
 +    goto err;
 +  }
 +
 +  if (tor_addr_from_getsockname(addr, sock) < 0) {
 +    int e = tor_socket_errno(sock);
 +    log_fn(severity, LD_NET, "getsockname() to determine interface failed: %s",
 +           tor_socket_strerror(e));
 +    goto err;
 +  }
 +
 +  if (tor_addr_is_loopback(addr) || tor_addr_is_multicast(addr)) {
 +    log_fn(severity, LD_NET, "Address that we determined via UDP socket"
 +           " magic is unsuitable for public comms.");
 +  } else {
 +    r=0;
 +  }
 +
 + err:
 +  if (sock >= 0)
 +    tor_close_socket(sock);
 +  if (r == -1)
 +    memset(addr, 0, sizeof(tor_addr_t));
 +  return r;
 +}
 +
 +/** Set *<b>addr</b> to an arbitrary IP address (if any) of an interface that
 + * connects to the Internet.  Prefer public IP addresses to internal IP
 + * addresses.  This address should only be used in checking whether our
 + * address has changed, as it may be an internal IP address.  Return 0 on
 + * success, -1 on failure.
 + * Prefer get_interface_address6_list for a list of all addresses on all
 + * interfaces which connect to the Internet.
 + */
 +MOCK_IMPL(int,
 +get_interface_address6,(int severity, sa_family_t family, tor_addr_t *addr))
 +{
 +  smartlist_t *addrs;
 +  int rv = -1;
 +  tor_assert(addr);
 +
 +  memset(addr, 0, sizeof(tor_addr_t));
 +
 +  /* Get a list of public or internal IPs in arbitrary order */
 +  addrs = get_interface_address6_list(severity, family, 1);
 +
 +  /* Find the first non-internal address, or the last internal address
 +   * Ideally, we want the default route, see #12377 for details */
 +  SMARTLIST_FOREACH_BEGIN(addrs, tor_addr_t *, a) {
 +    tor_addr_copy(addr, a);
 +    rv = 0;
 +
 +    /* If we found a non-internal address, declare success.  Otherwise,
 +     * keep looking. */
 +    if (!tor_addr_is_internal(a, 0))
 +      break;
 +  } SMARTLIST_FOREACH_END(a);
 +
 +  interface_address6_list_free(addrs);
 +  return rv;
 +}
 +
 +/** Free a smartlist of IP addresses returned by get_interface_address6_list.
 + */
 +void
 +interface_address6_list_free_(smartlist_t *addrs)
 +{
 +  if (addrs != NULL) {
 +    SMARTLIST_FOREACH(addrs, tor_addr_t *, a, tor_free(a));
 +    smartlist_free(addrs);
 +  }
 +}
 +
 +/** Return a smartlist of the IP addresses of type family from all interfaces
 + * on the server. Excludes loopback and multicast addresses. Only includes
 + * internal addresses if include_internal is true. (Note that a relay behind
 + * NAT may use an internal address to connect to the Internet.)
 + * An empty smartlist means that there are no addresses of the selected type
 + * matching these criteria.
 + * Returns NULL on failure.
 + * Use interface_address6_list_free to free the returned list.
 + */
 +MOCK_IMPL(smartlist_t *,
 +get_interface_address6_list,(int severity,
 +                             sa_family_t family,
 +                             int include_internal))
 +{
 +  smartlist_t *addrs;
 +  tor_addr_t addr;
 +
 +  /* Try to do this the smart way if possible. */
 +  if ((addrs = get_interface_addresses_raw(severity, family))) {
 +    SMARTLIST_FOREACH_BEGIN(addrs, tor_addr_t *, a)
 +    {
 +      if (tor_addr_is_loopback(a) ||
 +          tor_addr_is_multicast(a)) {
 +        SMARTLIST_DEL_CURRENT_KEEPORDER(addrs, a);
 +        tor_free(a);
 +        continue;
 +      }
 +
 +      if (!include_internal && tor_addr_is_internal(a, 0)) {
 +        SMARTLIST_DEL_CURRENT_KEEPORDER(addrs, a);
 +        tor_free(a);
 +        continue;
 +      }
 +    } SMARTLIST_FOREACH_END(a);
 +  }
 +
 +  if (addrs && smartlist_len(addrs) > 0) {
 +    return addrs;
 +  }
 +
 +  /* if we removed all entries as unsuitable */
 +  if (addrs) {
 +    smartlist_free(addrs);
 +  }
 +
 +  /* Okay, the smart way is out. */
 +  addrs = smartlist_new();
 +
 +  if (family == AF_INET || family == AF_UNSPEC) {
 +    if (get_interface_address6_via_udp_socket_hack(severity,AF_INET,
 +                                                   &addr) == 0) {
 +      if (include_internal || !tor_addr_is_internal(&addr, 0)) {
 +        smartlist_add(addrs, tor_memdup(&addr, sizeof(addr)));
 +      }
 +    }
 +  }
 +
 +  if (family == AF_INET6 || family == AF_UNSPEC) {
 +    if (get_interface_address6_via_udp_socket_hack(severity,AF_INET6,
 +                                                   &addr) == 0) {
 +      if (include_internal || !tor_addr_is_internal(&addr, 0)) {
 +        smartlist_add(addrs, tor_memdup(&addr, sizeof(addr)));
 +      }
 +    }
 +  }
 +
 +  return addrs;
 +}
 +
 +/* ======
 + * IPv4 helpers
 + * XXXX IPv6 deprecate some of these.
 + */
 +
 +/** Given an address of the form "ip:port", try to divide it into its
 + * ip and port portions, setting *<b>address_out</b> to a newly
 + * allocated string holding the address portion and *<b>port_out</b>
 + * to the port.
 + *
 + * Don't do DNS lookups and don't allow domain names in the "ip" field.
 + *
 + * If <b>default_port</b> is less than 0, don't accept <b>addrport</b> of the
 + * form "ip" or "ip:0".  Otherwise, accept those forms, and set
 + * *<b>port_out</b> to <b>default_port</b>.
 + *
 + * Return 0 on success, -1 on failure. */
 +int
 +tor_addr_port_parse(int severity, const char *addrport,
 +                    tor_addr_t *address_out, uint16_t *port_out,
 +                    int default_port)
 +{
 +  int retval = -1;
 +  int r;
 +  char *addr_tmp = NULL;
 +
 +  tor_assert(addrport);
 +  tor_assert(address_out);
 +  tor_assert(port_out);
 +
 +  r = tor_addr_port_split(severity, addrport, &addr_tmp, port_out);
 +  if (r < 0)
 +    goto done;
 +
 +  if (!*port_out) {
 +    if (default_port >= 0)
 +      *port_out = default_port;
 +    else
 +      goto done;
 +  }
 +
 +  /* make sure that address_out is an IP address */
 +  if (tor_addr_parse(address_out, addr_tmp) < 0)
 +    goto done;
 +
 +  retval = 0;
 +
 + done:
 +  tor_free(addr_tmp);
 +  return retval;
 +}
 +
 +/** Given an address of the form "host[:port]", try to divide it into its host
 + * and port portions, setting *<b>address_out</b> to a newly allocated string
 + * holding the address portion and *<b>port_out</b> to the port (or 0 if no
 + * port is given).  Return 0 on success, -1 on failure. */
 +int
 +tor_addr_port_split(int severity, const char *addrport,
 +                    char **address_out, uint16_t *port_out)
 +{
 +  tor_addr_t a_tmp;
 +  tor_assert(addrport);
 +  tor_assert(address_out);
 +  tor_assert(port_out);
 +  /* We need to check for IPv6 manually because the logic below doesn't
 +   * do a good job on IPv6 addresses that lack a port. */
 +  if (tor_addr_parse(&a_tmp, addrport) == AF_INET6) {
 +    *port_out = 0;
 +    *address_out = tor_strdup(addrport);
 +    return 0;
 +  }
 +
 +  const char *colon;
 +  char *address_ = NULL;
 +  int port_;
 +  int ok = 1;
 +
 +  colon = strrchr(addrport, ':');
 +  if (colon) {
 +    address_ = tor_strndup(addrport, colon-addrport);
 +    port_ = (int) tor_parse_long(colon+1,10,1,65535,NULL,NULL);
 +    if (!port_) {
 +      log_fn(severity, LD_GENERAL, "Port %s out of range", escaped(colon+1));
 +      ok = 0;
 +    }
 +    if (!port_out) {
 +      char *esc_addrport = esc_for_log(addrport);
 +      log_fn(severity, LD_GENERAL,
 +             "Port %s given on %s when not required",
 +             escaped(colon+1), esc_addrport);
 +      tor_free(esc_addrport);
 +      ok = 0;
 +    }
 +  } else {
 +    address_ = tor_strdup(addrport);
 +    port_ = 0;
 +  }
 +
 +  if (ok) {
 +    *address_out = address_;
 +  } else {
 +    *address_out = NULL;
 +    tor_free(address_);
 +  }
 +
 +  if (port_out)
 +    *port_out = ok ? ((uint16_t) port_) : 0;
 +
 +  return ok ? 0 : -1;
 +}
 +
 +/** If <b>mask</b> is an address mask for a bit-prefix, return the number of
 + * bits.  Otherwise, return -1. */
 +int
 +addr_mask_get_bits(uint32_t mask)
 +{
 +  int i;
 +  if (mask == 0)
 +    return 0;
 +  if (mask == 0xFFFFFFFFu)
 +    return 32;
 +  for (i=1; i<=32; ++i) {
 +    if (mask == (uint32_t) ~((1u<<(32-i))-1)) {
 +      return i;
 +    }
 +  }
 +  return -1;
 +}
 +
 +/** Parse a string <b>s</b> in the format of (*|port(-maxport)?)?, setting the
 + * various *out pointers as appropriate.  Return 0 on success, -1 on failure.
 + */
 +int
 +parse_port_range(const char *port, uint16_t *port_min_out,
 +                 uint16_t *port_max_out)
 +{
 +  int port_min, port_max, ok;
 +  tor_assert(port_min_out);
 +  tor_assert(port_max_out);
 +
 +  if (!port || *port == '\0' || strcmp(port, "*") == 0) {
 +    port_min = 1;
 +    port_max = 65535;
 +  } else {
 +    char *endptr = NULL;
 +    port_min = (int)tor_parse_long(port, 10, 0, 65535, &ok, &endptr);
 +    if (!ok) {
 +      log_warn(LD_GENERAL,
 +               "Malformed port %s on address range; rejecting.",
 +               escaped(port));
 +      return -1;
 +    } else if (endptr && *endptr == '-') {
 +      port = endptr+1;
 +      endptr = NULL;
 +      port_max = (int)tor_parse_long(port, 10, 1, 65535, &ok, &endptr);
 +      if (!ok) {
 +        log_warn(LD_GENERAL,
 +                 "Malformed port %s on address range; rejecting.",
 +                 escaped(port));
 +        return -1;
 +      }
 +    } else {
 +      port_max = port_min;
 +    }
 +    if (port_min > port_max) {
 +      log_warn(LD_GENERAL, "Insane port range on address policy; rejecting.");
 +      return -1;
 +    }
 +  }
 +
 +  if (port_min < 1)
 +    port_min = 1;
 +  if (port_max > 65535)
 +    port_max = 65535;
 +
 +  *port_min_out = (uint16_t) port_min;
 +  *port_max_out = (uint16_t) port_max;
 +
 +  return 0;
 +}
 +
 +/** Given a host-order <b>addr</b>, call tor_inet_ntop() on it
 + *  and return a strdup of the resulting address.
 + */
 +char *
 +tor_dup_ip(uint32_t addr)
 +{
 +  char buf[TOR_ADDR_BUF_LEN];
 +  struct in_addr in;
 +
 +  in.s_addr = htonl(addr);
 +  tor_inet_ntop(AF_INET, &in, buf, sizeof(buf));
 +  return tor_strdup(buf);
 +}
 +
 +/**
 + * Set *<b>addr</b> to a host-order IPv4 address (if any) of an
 + * interface that connects to the Internet.  Prefer public IP addresses to
 + * internal IP addresses.  This address should only be used in checking
 + * whether our address has changed, as it may be an internal IPv4 address.
 + * Return 0 on success, -1 on failure.
 + * Prefer get_interface_address_list6 for a list of all IPv4 and IPv6
 + * addresses on all interfaces which connect to the Internet.
 + */
 +MOCK_IMPL(int,
 +get_interface_address,(int severity, uint32_t *addr))
 +{
 +  tor_addr_t local_addr;
 +  int r;
 +
 +  memset(addr, 0, sizeof(uint32_t));
 +
 +  r = get_interface_address6(severity, AF_INET, &local_addr);
 +  if (r>=0)
 +    *addr = tor_addr_to_ipv4h(&local_addr);
 +  return r;
 +}
 +
 +/** Return true if we can tell that <b>name</b> is a canonical name for the
 + * loopback address.  Return true also for *.local hostnames, which are
 + * multicast DNS names for hosts on the local network. */
 +int
 +tor_addr_hostname_is_local(const char *name)
 +{
 +  return !strcasecmp(name, "localhost") ||
 +    !strcasecmp(name, "local") ||
 +    !strcasecmpend(name, ".local");
 +}
 +
 +/** Return a newly allocated tor_addr_port_t with <b>addr</b> and
 +    <b>port</b> filled in. */
 +tor_addr_port_t *
 +tor_addr_port_new(const tor_addr_t *addr, uint16_t port)
 +{
 +  tor_addr_port_t *ap = tor_malloc_zero(sizeof(tor_addr_port_t));
 +  if (addr)
 +    tor_addr_copy(&ap->addr, addr);
 +  ap->port = port;
 +  return ap;
 +}
 +
 +/** Return true iff <a>a</b> and <b>b</b> are the same address and port */
 +int
 +tor_addr_port_eq(const tor_addr_port_t *a,
 +                 const tor_addr_port_t *b)
 +{
 +  return tor_addr_eq(&a->addr, &b->addr) && a->port == b->port;
 +}
 +
 +/** Return true if <b>string</b> represents a valid IPv4 adddress in
 + * 'a.b.c.d' form.
 + */
 +int
 +string_is_valid_ipv4_address(const char *string)
 +{
 +  struct in_addr addr;
 +
 +  return (tor_inet_pton(AF_INET,string,&addr) == 1);
 +}
 +
 +/** Return true if <b>string</b> represents a valid IPv6 address in
 + * a form that inet_pton() can parse.
 + */
 +int
 +string_is_valid_ipv6_address(const char *string)
 +{
 +  struct in6_addr addr;
 +
 +  return (tor_inet_pton(AF_INET6,string,&addr) == 1);
 +}
 +
 +/** Return true iff <b>string</b> is a valid destination address,
 + * i.e. either a DNS hostname or IPv4/IPv6 address string.
 + */
 +int
 +string_is_valid_dest(const char *string)
 +{
 +  char *tmp = NULL;
 +  int retval;
 +  size_t len;
 +
 +  if (string == NULL)
 +    return 0;
 +
 +  len = strlen(string);
 +
 +  if (len == 0)
 +    return 0;
 +
 +  if (string[0] == '[' && string[len - 1] == ']')
 +    string = tmp = tor_strndup(string + 1, len - 2);
 +
 +  retval = string_is_valid_ipv4_address(string) ||
 +    string_is_valid_ipv6_address(string) ||
 +    string_is_valid_nonrfc_hostname(string);
 +
 +  tor_free(tmp);
 +
 +  return retval;
 +}
 +
 +/** Return true iff <b>string</b> matches a pattern of DNS names
 + * that we allow Tor clients to connect to.
 + *
 + * Note: This allows certain technically invalid characters ('_') to cope
 + * with misconfigured zones that have been encountered in the wild.
 + */
 +int
 +string_is_valid_nonrfc_hostname(const char *string)
 +{
 +  int result = 1;
 +  int has_trailing_dot;
 +  char *last_label;
 +  smartlist_t *components;
 +
 +  if (!string || strlen(string) == 0)
 +    return 0;
 +
 +  if (string_is_valid_ipv4_address(string))
 +    return 0;
 +
 +  components = smartlist_new();
 +
 +  smartlist_split_string(components,string,".",0,0);
 +
 +  if (BUG(smartlist_len(components) == 0))
 +    return 0; // LCOV_EXCL_LINE should be impossible given the earlier checks.
 +
 +  /* Allow a single terminating '.' used rarely to indicate domains
 +   * are FQDNs rather than relative. */
 +  last_label = (char *)smartlist_get(components,
 +                                     smartlist_len(components) - 1);
 +  has_trailing_dot = (last_label[0] == '\0');
 +  if (has_trailing_dot) {
 +    smartlist_pop_last(components);
 +    tor_free(last_label);
 +    last_label = NULL;
 +  }
 +
 +  SMARTLIST_FOREACH_BEGIN(components, char *, c) {
 +    if ((c[0] == '-') || (*c == '_')) {
 +      result = 0;
 +      break;
 +    }
 +
 +    do {
 +      result = (TOR_ISALNUM(*c) || (*c == '-') || (*c == '_'));
 +      c++;
 +    } while (result && *c);
 +
 +    if (result == 0) {
 +      break;
 +    }
 +  } SMARTLIST_FOREACH_END(c);
 +
 +  SMARTLIST_FOREACH_BEGIN(components, char *, c) {
 +    tor_free(c);
 +  } SMARTLIST_FOREACH_END(c);
 +
 +  smartlist_free(components);
 +
 +  return result;
 +}
diff --cc src/test/test_addr.c
index 985f43b3f,5c4b6449c..8868edce2
--- a/src/test/test_addr.c
+++ b/src/test/test_addr.c
@@@ -1203,5 -1093,7 +1220,6 @@@ struct testcase_t addr_tests[] = 
    { "sockaddr_to_str", test_addr_sockaddr_to_str, 0, NULL, NULL },
    { "is_loopback", test_addr_is_loopback, 0, NULL, NULL },
    { "make_null", test_addr_make_null, 0, NULL, NULL },
+   { "rfc6598", test_addr_rfc6598, 0, NULL, NULL },
    END_OF_TESTCASES
  };
 -





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