Update ipp documentation to reflect the behavior of configuring WiFi on IPP USB printers.

[thirdparty/cups.git] / cups / http-support.c

/*
 * HTTP support routines for CUPS.
 *
 * Copyright 2007-2019 by Apple Inc.
 * Copyright 1997-2007 by Easy Software Products, all rights reserved.
 *
 * Licensed under Apache License v2.0.  See the file "LICENSE" for more
 * information.
 */

/*
 * Include necessary headers...
 */

#include "cups-private.h"
#include "debug-internal.h"
#ifdef HAVE_DNSSD
#  include <dns_sd.h>
#  ifdef _WIN32
#    include <io.h>
#  elif defined(HAVE_POLL)
#    include <poll.h>
#  else
#    include <sys/select.h>
#  endif /* _WIN32 */
#elif defined(HAVE_AVAHI)
#  include <avahi-client/client.h>
#  include <avahi-client/lookup.h>
#  include <avahi-common/simple-watch.h>
#endif /* HAVE_DNSSD */


/*
 * Local types...
 */

typedef struct _http_uribuf_s           /* URI buffer */
{
#ifdef HAVE_AVAHI
  AvahiSimplePoll       *poll;          /* Poll state */
#endif /* HAVE_AVAHI */
  char                  *buffer;        /* Pointer to buffer */
  size_t                bufsize;        /* Size of buffer */
  int                   options;        /* Options passed to _httpResolveURI */
  const char            *resource;      /* Resource from URI */
  const char            *uuid;          /* UUID from URI */
} _http_uribuf_t;


/*
 * Local globals...
 */

static const char * const http_days[7] =/* Days of the week */
                        {
                          "Sun",
                          "Mon",
                          "Tue",
                          "Wed",
                          "Thu",
                          "Fri",
                          "Sat"
                        };
static const char * const http_months[12] =
                        {               /* Months of the year */
                          "Jan",
                          "Feb",
                          "Mar",
                          "Apr",
                          "May",
                          "Jun",
                          "Jul",
                          "Aug",
                          "Sep",
                          "Oct",
                          "Nov",
                          "Dec"
                        };
static const char * const http_states[] =
                        {               /* HTTP state strings */
                          "HTTP_STATE_ERROR",
                          "HTTP_STATE_WAITING",
                          "HTTP_STATE_OPTIONS",
                          "HTTP_STATE_GET",
                          "HTTP_STATE_GET_SEND",
                          "HTTP_STATE_HEAD",
                          "HTTP_STATE_POST",
                          "HTTP_STATE_POST_RECV",
                          "HTTP_STATE_POST_SEND",
                          "HTTP_STATE_PUT",
                          "HTTP_STATE_PUT_RECV",
                          "HTTP_STATE_DELETE",
                          "HTTP_STATE_TRACE",
                          "HTTP_STATE_CONNECT",
                          "HTTP_STATE_STATUS",
                          "HTTP_STATE_UNKNOWN_METHOD",
                          "HTTP_STATE_UNKNOWN_VERSION"
                        };


/*
 * Local functions...
 */

static const char       *http_copy_decode(char *dst, const char *src,
                                          int dstsize, const char *term,
                                          int decode);
static char             *http_copy_encode(char *dst, const char *src,
                                          char *dstend, const char *reserved,
                                          const char *term, int encode);
#ifdef HAVE_DNSSD
static void DNSSD_API   http_resolve_cb(DNSServiceRef sdRef,
                                        DNSServiceFlags flags,
                                        uint32_t interfaceIndex,
                                        DNSServiceErrorType errorCode,
                                        const char *fullName,
                                        const char *hostTarget,
                                        uint16_t port, uint16_t txtLen,
                                        const unsigned char *txtRecord,
                                        void *context);
#endif /* HAVE_DNSSD */

#ifdef HAVE_AVAHI
static void     http_client_cb(AvahiClient *client,
                               AvahiClientState state, void *simple_poll);
static int      http_poll_cb(struct pollfd *pollfds, unsigned int num_pollfds,
                             int timeout, void *context);
static void     http_resolve_cb(AvahiServiceResolver *resolver,
                                AvahiIfIndex interface,
                                AvahiProtocol protocol,
                                AvahiResolverEvent event,
                                const char *name, const char *type,
                                const char *domain, const char *host_name,
                                const AvahiAddress *address, uint16_t port,
                                AvahiStringList *txt,
                                AvahiLookupResultFlags flags, void *context);
#endif /* HAVE_AVAHI */


/*
 * 'httpAssembleURI()' - Assemble a uniform resource identifier from its
 *                       components.
 *
 * This function escapes reserved characters in the URI depending on the
 * value of the "encoding" argument.  You should use this function in
 * place of traditional string functions whenever you need to create a
 * URI string.
 *
 * @since CUPS 1.2/macOS 10.5@
 */

http_uri_status_t                       /* O - URI status */
httpAssembleURI(
    http_uri_coding_t encoding,         /* I - Encoding flags */
    char              *uri,             /* I - URI buffer */
    int               urilen,           /* I - Size of URI buffer */
    const char        *scheme,          /* I - Scheme name */
    const char        *username,        /* I - Username */
    const char        *host,            /* I - Hostname or address */
    int               port,             /* I - Port number */
    const char        *resource)        /* I - Resource */
{
  char          *ptr,                   /* Pointer into URI buffer */
                *end;                   /* End of URI buffer */


 /*
  * Range check input...
  */

  if (!uri || urilen < 1 || !scheme || port < 0)
  {
    if (uri)
      *uri = '\0';

    return (HTTP_URI_STATUS_BAD_ARGUMENTS);
  }

 /*
  * Assemble the URI starting with the scheme...
  */

  end = uri + urilen - 1;
  ptr = http_copy_encode(uri, scheme, end, NULL, NULL, 0);

  if (!ptr)
    goto assemble_overflow;

  if (!strcmp(scheme, "geo") || !strcmp(scheme, "mailto") || !strcmp(scheme, "tel"))
  {
   /*
    * geo:, mailto:, and tel: only have :, no //...
    */

    if (ptr < end)
      *ptr++ = ':';
    else
      goto assemble_overflow;
  }
  else
  {
   /*
    * Schemes other than geo:, mailto:, and tel: typically have //...
    */

    if ((ptr + 2) < end)
    {
      *ptr++ = ':';
      *ptr++ = '/';
      *ptr++ = '/';
    }
    else
      goto assemble_overflow;
  }

 /*
  * Next the username and hostname, if any...
  */

  if (host)
  {
    const char  *hostptr;               /* Pointer into hostname */
    int         have_ipv6;              /* Do we have an IPv6 address? */

    if (username && *username)
    {
     /*
      * Add username@ first...
      */

      ptr = http_copy_encode(ptr, username, end, "/?#[]@", NULL,
                             encoding & HTTP_URI_CODING_USERNAME);

      if (!ptr)
        goto assemble_overflow;

      if (ptr < end)
        *ptr++ = '@';
      else
        goto assemble_overflow;
    }

   /*
    * Then add the hostname.  Since IPv6 is a particular pain to deal
    * with, we have several special cases to deal with.  If we get
    * an IPv6 address with brackets around it, assume it is already in
    * URI format.  Since DNS-SD service names can sometimes look like
    * raw IPv6 addresses, we specifically look for "._tcp" in the name,
    * too...
    */

    for (hostptr = host,
             have_ipv6 = strchr(host, ':') && !strstr(host, "._tcp");
         *hostptr && have_ipv6;
         hostptr ++)
      if (*hostptr != ':' && !isxdigit(*hostptr & 255))
      {
        have_ipv6 = *hostptr == '%';
        break;
      }

    if (have_ipv6)
    {
     /*
      * We have a raw IPv6 address...
      */

      if (strchr(host, '%') && !(encoding & HTTP_URI_CODING_RFC6874))
      {
       /*
        * We have a link-local address, add "[v1." prefix...
        */

        if ((ptr + 4) < end)
        {
          *ptr++ = '[';
          *ptr++ = 'v';
          *ptr++ = '1';
          *ptr++ = '.';
        }
        else
          goto assemble_overflow;
      }
      else
      {
       /*
        * We have a normal (or RFC 6874 link-local) address, add "[" prefix...
        */

        if (ptr < end)
          *ptr++ = '[';
        else
          goto assemble_overflow;
      }

     /*
      * Copy the rest of the IPv6 address, and terminate with "]".
      */

      while (ptr < end && *host)
      {
        if (*host == '%')
        {
         /*
          * Convert/encode zone separator
          */

          if (encoding & HTTP_URI_CODING_RFC6874)
          {
            if (ptr >= (end - 2))
              goto assemble_overflow;

            *ptr++ = '%';
            *ptr++ = '2';
            *ptr++ = '5';
          }
          else
            *ptr++ = '+';

          host ++;
        }
        else
          *ptr++ = *host++;
      }

      if (*host)
        goto assemble_overflow;

      if (ptr < end)
        *ptr++ = ']';
      else
        goto assemble_overflow;
    }
    else
    {
     /*
      * Otherwise, just copy the host string (the extra chars are not in the
      * "reg-name" ABNF rule; anything <= SP or >= DEL plus % gets automatically
      * percent-encoded.
      */

      ptr = http_copy_encode(ptr, host, end, "\"#/:<>?@[\\]^`{|}", NULL,
                             encoding & HTTP_URI_CODING_HOSTNAME);

      if (!ptr)
        goto assemble_overflow;
    }

   /*
    * Finish things off with the port number...
    */

    if (port > 0)
    {
      snprintf(ptr, (size_t)(end - ptr + 1), ":%d", port);
      ptr += strlen(ptr);

      if (ptr >= end)
        goto assemble_overflow;
    }
  }

 /*
  * Last but not least, add the resource string...
  */

  if (resource)
  {
    char        *query;                 /* Pointer to query string */


   /*
    * Copy the resource string up to the query string if present...
    */

    query = strchr(resource, '?');
    ptr   = http_copy_encode(ptr, resource, end, NULL, "?",
                             encoding & HTTP_URI_CODING_RESOURCE);
    if (!ptr)
      goto assemble_overflow;

    if (query)
    {
     /*
      * Copy query string without encoding...
      */

      ptr = http_copy_encode(ptr, query, end, NULL, NULL,
                             encoding & HTTP_URI_CODING_QUERY);
      if (!ptr)
        goto assemble_overflow;
    }
  }
  else if (ptr < end)
    *ptr++ = '/';
  else
    goto assemble_overflow;

 /*
  * Nul-terminate the URI buffer and return with no errors...
  */

  *ptr = '\0';

  return (HTTP_URI_STATUS_OK);

 /*
  * Clear the URI string and return an overflow error; I don't usually
  * like goto's, but in this case it makes sense...
  */

  assemble_overflow:

  *uri = '\0';
  return (HTTP_URI_STATUS_OVERFLOW);
}


/*
 * 'httpAssembleURIf()' - Assemble a uniform resource identifier from its
 *                        components with a formatted resource.
 *
 * This function creates a formatted version of the resource string
 * argument "resourcef" and escapes reserved characters in the URI
 * depending on the value of the "encoding" argument.  You should use
 * this function in place of traditional string functions whenever
 * you need to create a URI string.
 *
 * @since CUPS 1.2/macOS 10.5@
 */

http_uri_status_t                       /* O - URI status */
httpAssembleURIf(
    http_uri_coding_t encoding,         /* I - Encoding flags */
    char              *uri,             /* I - URI buffer */
    int               urilen,           /* I - Size of URI buffer */
    const char        *scheme,          /* I - Scheme name */
    const char        *username,        /* I - Username */
    const char        *host,            /* I - Hostname or address */
    int               port,             /* I - Port number */
    const char        *resourcef,       /* I - Printf-style resource */
    ...)                                /* I - Additional arguments as needed */
{
  va_list       ap;                     /* Pointer to additional arguments */
  char          resource[1024];         /* Formatted resource string */
  int           bytes;                  /* Bytes in formatted string */


 /*
  * Range check input...
  */

  if (!uri || urilen < 1 || !scheme || port < 0 || !resourcef)
  {
    if (uri)
      *uri = '\0';

    return (HTTP_URI_STATUS_BAD_ARGUMENTS);
  }

 /*
  * Format the resource string and assemble the URI...
  */

  va_start(ap, resourcef);
  bytes = vsnprintf(resource, sizeof(resource), resourcef, ap);
  va_end(ap);

  if ((size_t)bytes >= sizeof(resource))
  {
    *uri = '\0';
    return (HTTP_URI_STATUS_OVERFLOW);
  }
  else
    return (httpAssembleURI(encoding,  uri, urilen, scheme, username, host,
                            port, resource));
}


/*
 * 'httpAssembleUUID()' - Assemble a name-based UUID URN conforming to RFC 4122.
 *
 * This function creates a unique 128-bit identifying number using the server
 * name, port number, random data, and optionally an object name and/or object
 * number.  The result is formatted as a UUID URN as defined in RFC 4122.
 *
 * The buffer needs to be at least 46 bytes in size.
 *
 * @since CUPS 1.7/macOS 10.9@
 */

char *                                  /* I - UUID string */
httpAssembleUUID(const char *server,    /* I - Server name */
                 int        port,       /* I - Port number */
                 const char *name,      /* I - Object name or NULL */
                 int        number,     /* I - Object number or 0 */
                 char       *buffer,    /* I - String buffer */
                 size_t     bufsize)    /* I - Size of buffer */
{
  char                  data[1024];     /* Source string for MD5 */
  unsigned char         md5sum[16];     /* MD5 digest/sum */


 /*
  * Build a version 3 UUID conforming to RFC 4122.
  *
  * Start with the MD5 sum of the server, port, object name and
  * number, and some random data on the end.
  */

  snprintf(data, sizeof(data), "%s:%d:%s:%d:%04x:%04x", server,
           port, name ? name : server, number,
           (unsigned)CUPS_RAND() & 0xffff, (unsigned)CUPS_RAND() & 0xffff);

  cupsHashData("md5", (unsigned char *)data, strlen(data), md5sum, sizeof(md5sum));

 /*
  * Generate the UUID from the MD5...
  */

  snprintf(buffer, bufsize,
           "urn:uuid:%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-"
           "%02x%02x%02x%02x%02x%02x",
           md5sum[0], md5sum[1], md5sum[2], md5sum[3], md5sum[4], md5sum[5],
           (md5sum[6] & 15) | 0x30, md5sum[7], (md5sum[8] & 0x3f) | 0x40,
           md5sum[9], md5sum[10], md5sum[11], md5sum[12], md5sum[13],
           md5sum[14], md5sum[15]);

  return (buffer);
}


/*
 * 'httpDecode64()' - Base64-decode a string.
 *
 * This function is deprecated. Use the httpDecode64_2() function instead
 * which provides buffer length arguments.
 *
 * @deprecated@ @exclude all@
 */

char *                                  /* O - Decoded string */
httpDecode64(char       *out,           /* I - String to write to */
             const char *in)            /* I - String to read from */
{
  int   outlen;                         /* Output buffer length */


 /*
  * Use the old maximum buffer size for binary compatibility...
  */

  outlen = 512;

  return (httpDecode64_2(out, &outlen, in));
}


/*
 * 'httpDecode64_2()' - Base64-decode a string.
 *
 * The caller must initialize "outlen" to the maximum size of the decoded
 * string before calling @code httpDecode64_2@.  On return "outlen" contains the
 * decoded length of the string.
 *
 * @since CUPS 1.1.21/macOS 10.4@
 */

char *                                  /* O  - Decoded string */
httpDecode64_2(char       *out,         /* I  - String to write to */
               int        *outlen,      /* IO - Size of output string */
               const char *in)          /* I  - String to read from */
{
  int           pos;                    /* Bit position */
  unsigned      base64;                 /* Value of this character */
  char          *outptr,                /* Output pointer */
                *outend;                /* End of output buffer */


 /*
  * Range check input...
  */

  if (!out || !outlen || *outlen < 1 || !in)
    return (NULL);

  if (!*in)
  {
    *out    = '\0';
    *outlen = 0;

    return (out);
  }

 /*
  * Convert from base-64 to bytes...
  */

  for (outptr = out, outend = out + *outlen - 1, pos = 0; *in != '\0'; in ++)
  {
   /*
    * Decode this character into a number from 0 to 63...
    */

    if (*in >= 'A' && *in <= 'Z')
      base64 = (unsigned)(*in - 'A');
    else if (*in >= 'a' && *in <= 'z')
      base64 = (unsigned)(*in - 'a' + 26);
    else if (*in >= '0' && *in <= '9')
      base64 = (unsigned)(*in - '0' + 52);
    else if (*in == '+')
      base64 = 62;
    else if (*in == '/')
      base64 = 63;
    else if (*in == '=')
      break;
    else
      continue;

   /*
    * Store the result in the appropriate chars...
    */

    switch (pos)
    {
      case 0 :
          if (outptr < outend)
            *outptr = (char)(base64 << 2);
          pos ++;
          break;
      case 1 :
          if (outptr < outend)
            *outptr++ |= (char)((base64 >> 4) & 3);
          if (outptr < outend)
            *outptr = (char)((base64 << 4) & 255);
          pos ++;
          break;
      case 2 :
          if (outptr < outend)
            *outptr++ |= (char)((base64 >> 2) & 15);
          if (outptr < outend)
            *outptr = (char)((base64 << 6) & 255);
          pos ++;
          break;
      case 3 :
          if (outptr < outend)
            *outptr++ |= (char)base64;
          pos = 0;
          break;
    }
  }

  *outptr = '\0';

 /*
  * Return the decoded string and size...
  */

  *outlen = (int)(outptr - out);

  return (out);
}


/*
 * 'httpEncode64()' - Base64-encode a string.
 *
 * This function is deprecated. Use the httpEncode64_2() function instead
 * which provides buffer length arguments.
 *
 * @deprecated@ @exclude all@
 */

char *                                  /* O - Encoded string */
httpEncode64(char       *out,           /* I - String to write to */
             const char *in)            /* I - String to read from */
{
  return (httpEncode64_2(out, 512, in, (int)strlen(in)));
}


/*
 * 'httpEncode64_2()' - Base64-encode a string.
 *
 * @since CUPS 1.1.21/macOS 10.4@
 */

char *                                  /* O - Encoded string */
httpEncode64_2(char       *out,         /* I - String to write to */
               int        outlen,       /* I - Maximum size of output string */
               const char *in,          /* I - String to read from */
               int        inlen)        /* I - Size of input string */
{
  char          *outptr,                /* Output pointer */
                *outend;                /* End of output buffer */
  static const char base64[] =          /* Base64 characters... */
                {
                  "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                  "abcdefghijklmnopqrstuvwxyz"
                  "0123456789"
                  "+/"
                };


 /*
  * Range check input...
  */

  if (!out || outlen < 1 || !in)
    return (NULL);

 /*
  * Convert bytes to base-64...
  */

  for (outptr = out, outend = out + outlen - 1; inlen > 0; in ++, inlen --)
  {
   /*
    * Encode the up to 3 characters as 4 Base64 numbers...
    */

    if (outptr < outend)
      *outptr ++ = base64[(in[0] & 255) >> 2];

    if (outptr < outend)
    {
      if (inlen > 1)
        *outptr ++ = base64[(((in[0] & 255) << 4) | ((in[1] & 255) >> 4)) & 63];
      else
        *outptr ++ = base64[((in[0] & 255) << 4) & 63];
    }

    in ++;
    inlen --;
    if (inlen <= 0)
    {
      if (outptr < outend)
        *outptr ++ = '=';
      if (outptr < outend)
        *outptr ++ = '=';
      break;
    }

    if (outptr < outend)
    {
      if (inlen > 1)
        *outptr ++ = base64[(((in[0] & 255) << 2) | ((in[1] & 255) >> 6)) & 63];
      else
        *outptr ++ = base64[((in[0] & 255) << 2) & 63];
    }

    in ++;
    inlen --;
    if (inlen <= 0)
    {
      if (outptr < outend)
        *outptr ++ = '=';
      break;
    }

    if (outptr < outend)
      *outptr ++ = base64[in[0] & 63];
  }

  *outptr = '\0';

 /*
  * Return the encoded string...
  */

  return (out);
}


/*
 * 'httpGetDateString()' - Get a formatted date/time string from a time value.
 *
 * @deprecated@ @exclude all@
 */

const char *                            /* O - Date/time string */
httpGetDateString(time_t t)             /* I - Time in seconds */
{
  _cups_globals_t *cg = _cupsGlobals(); /* Pointer to library globals */


  return (httpGetDateString2(t, cg->http_date, sizeof(cg->http_date)));
}


/*
 * 'httpGetDateString2()' - Get a formatted date/time string from a time value.
 *
 * @since CUPS 1.2/macOS 10.5@
 */

const char *                            /* O - Date/time string */
httpGetDateString2(time_t t,            /* I - Time in seconds */
                   char   *s,           /* I - String buffer */
                   int    slen)         /* I - Size of string buffer */
{
  struct tm     tdate;                  /* UNIX date/time data */


  gmtime_r(&t, &tdate);

  snprintf(s, (size_t)slen, "%s, %02d %s %d %02d:%02d:%02d GMT", http_days[tdate.tm_wday], tdate.tm_mday, http_months[tdate.tm_mon], tdate.tm_year + 1900, tdate.tm_hour, tdate.tm_min, tdate.tm_sec);

  return (s);
}


/*
 * 'httpGetDateTime()' - Get a time value from a formatted date/time string.
 */

time_t                                  /* O - Time in seconds */
httpGetDateTime(const char *s)          /* I - Date/time string */
{
  int           i;                      /* Looping var */
  char          mon[16];                /* Abbreviated month name */
  int           day, year;              /* Day of month and year */
  int           hour, min, sec;         /* Time */
  int           days;                   /* Number of days since 1970 */
  static const int normal_days[] =      /* Days to a month, normal years */
                { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
  static const int leap_days[] =        /* Days to a month, leap years */
                { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 };


  DEBUG_printf(("2httpGetDateTime(s=\"%s\")", s));

 /*
  * Extract the date and time from the formatted string...
  */

  if (sscanf(s, "%*s%d%15s%d%d:%d:%d", &day, mon, &year, &hour, &min, &sec) < 6)
    return (0);

  DEBUG_printf(("4httpGetDateTime: day=%d, mon=\"%s\", year=%d, hour=%d, "
                "min=%d, sec=%d", day, mon, year, hour, min, sec));

 /*
  * Convert the month name to a number from 0 to 11.
  */

  for (i = 0; i < 12; i ++)
    if (!_cups_strcasecmp(mon, http_months[i]))
      break;

  if (i >= 12)
    return (0);

  DEBUG_printf(("4httpGetDateTime: i=%d", i));

 /*
  * Now convert the date and time to a UNIX time value in seconds since
  * 1970.  We can't use mktime() since the timezone may not be UTC but
  * the date/time string *is* UTC.
  */

  if ((year & 3) == 0 && ((year % 100) != 0 || (year % 400) == 0))
    days = leap_days[i] + day - 1;
  else
    days = normal_days[i] + day - 1;

  DEBUG_printf(("4httpGetDateTime: days=%d", days));

  days += (year - 1970) * 365 +         /* 365 days per year (normally) */
          ((year - 1) / 4 - 492) -      /* + leap days */
          ((year - 1) / 100 - 19) +     /* - 100 year days */
          ((year - 1) / 400 - 4);       /* + 400 year days */

  DEBUG_printf(("4httpGetDateTime: days=%d\n", days));

  return (days * 86400 + hour * 3600 + min * 60 + sec);
}


/*
 * 'httpSeparate()' - Separate a Universal Resource Identifier into its
 *                    components.
 *
 * This function is deprecated; use the httpSeparateURI() function instead.
 *
 * @deprecated@ @exclude all@
 */

void
httpSeparate(const char *uri,           /* I - Universal Resource Identifier */
             char       *scheme,        /* O - Scheme [32] (http, https, etc.) */
             char       *username,      /* O - Username [1024] */
             char       *host,          /* O - Hostname [1024] */
             int        *port,          /* O - Port number to use */
             char       *resource)      /* O - Resource/filename [1024] */
{
  httpSeparateURI(HTTP_URI_CODING_ALL, uri, scheme, 32, username,
                  HTTP_MAX_URI, host, HTTP_MAX_URI, port, resource,
                  HTTP_MAX_URI);
}


/*
 * 'httpSeparate2()' - Separate a Universal Resource Identifier into its
 *                     components.
 *
 * This function is deprecated; use the httpSeparateURI() function instead.
 *
 * @since CUPS 1.1.21/macOS 10.4@
 * @deprecated@ @exclude all@
 */

void
httpSeparate2(const char *uri,          /* I - Universal Resource Identifier */
              char       *scheme,       /* O - Scheme (http, https, etc.) */
              int        schemelen,     /* I - Size of scheme buffer */
              char       *username,     /* O - Username */
              int        usernamelen,   /* I - Size of username buffer */
              char       *host,         /* O - Hostname */
              int        hostlen,       /* I - Size of hostname buffer */
              int        *port,         /* O - Port number to use */
              char       *resource,     /* O - Resource/filename */
              int        resourcelen)   /* I - Size of resource buffer */
{
  httpSeparateURI(HTTP_URI_CODING_ALL, uri, scheme, schemelen, username,
                  usernamelen, host, hostlen, port, resource, resourcelen);
}


/*
 * 'httpSeparateURI()' - Separate a Universal Resource Identifier into its
 *                       components.
 *
 * @since CUPS 1.2/macOS 10.5@
 */

http_uri_status_t                       /* O - Result of separation */
httpSeparateURI(
    http_uri_coding_t decoding,         /* I - Decoding flags */
    const char        *uri,             /* I - Universal Resource Identifier */
    char              *scheme,          /* O - Scheme (http, https, etc.) */
    int               schemelen,        /* I - Size of scheme buffer */
    char              *username,        /* O - Username */
    int               usernamelen,      /* I - Size of username buffer */
    char              *host,            /* O - Hostname */
    int               hostlen,          /* I - Size of hostname buffer */
    int               *port,            /* O - Port number to use */
    char              *resource,        /* O - Resource/filename */
    int               resourcelen)      /* I - Size of resource buffer */
{
  char                  *ptr,           /* Pointer into string... */
                        *end;           /* End of string */
  const char            *sep;           /* Separator character */
  http_uri_status_t     status;         /* Result of separation */


 /*
  * Initialize everything to blank...
  */

  if (scheme && schemelen > 0)
    *scheme = '\0';

  if (username && usernamelen > 0)
    *username = '\0';

  if (host && hostlen > 0)
    *host = '\0';

  if (port)
    *port = 0;

  if (resource && resourcelen > 0)
    *resource = '\0';

 /*
  * Range check input...
  */

  if (!uri || !port || !scheme || schemelen <= 0 || !username ||
      usernamelen <= 0 || !host || hostlen <= 0 || !resource ||
      resourcelen <= 0)
    return (HTTP_URI_STATUS_BAD_ARGUMENTS);

  if (!*uri)
    return (HTTP_URI_STATUS_BAD_URI);

 /*
  * Grab the scheme portion of the URI...
  */

  status = HTTP_URI_STATUS_OK;

  if (!strncmp(uri, "//", 2))
  {
   /*
    * Workaround for HP IPP client bug...
    */

    strlcpy(scheme, "ipp", (size_t)schemelen);
    status = HTTP_URI_STATUS_MISSING_SCHEME;
  }
  else if (*uri == '/')
  {
   /*
    * Filename...
    */

    strlcpy(scheme, "file", (size_t)schemelen);
    status = HTTP_URI_STATUS_MISSING_SCHEME;
  }
  else
  {
   /*
    * Standard URI with scheme...
    */

    for (ptr = scheme, end = scheme + schemelen - 1;
         *uri && *uri != ':' && ptr < end;)
      if (strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                 "abcdefghijklmnopqrstuvwxyz"
                 "0123456789-+.", *uri) != NULL)
        *ptr++ = *uri++;
      else
        break;

    *ptr = '\0';

    if (*uri != ':' || *scheme == '.' || !*scheme)
    {
      *scheme = '\0';
      return (HTTP_URI_STATUS_BAD_SCHEME);
    }

    uri ++;
  }

 /*
  * Set the default port number...
  */

  if (!strcmp(scheme, "http"))
    *port = 80;
  else if (!strcmp(scheme, "https"))
    *port = 443;
  else if (!strcmp(scheme, "ipp") || !strcmp(scheme, "ipps"))
    *port = 631;
  else if (!_cups_strcasecmp(scheme, "lpd"))
    *port = 515;
  else if (!strcmp(scheme, "socket"))   /* Not yet registered with IANA... */
    *port = 9100;
  else if (strcmp(scheme, "file") && strcmp(scheme, "mailto") && strcmp(scheme, "tel"))
    status = HTTP_URI_STATUS_UNKNOWN_SCHEME;

 /*
  * Now see if we have a hostname...
  */

  if (!strncmp(uri, "//", 2))
  {
   /*
    * Yes, extract it...
    */

    uri += 2;

   /*
    * Grab the username, if any...
    */

    if ((sep = strpbrk(uri, "@/")) != NULL && *sep == '@')
    {
     /*
      * Get a username:password combo...
      */

      uri = http_copy_decode(username, uri, usernamelen, "@",
                             decoding & HTTP_URI_CODING_USERNAME);

      if (!uri)
      {
        *username = '\0';
        return (HTTP_URI_STATUS_BAD_USERNAME);
      }

      uri ++;
    }

   /*
    * Then the hostname/IP address...
    */

    if (*uri == '[')
    {
     /*
      * Grab IPv6 address...
      */

      uri ++;
      if (*uri == 'v')
      {
       /*
        * Skip IPvFuture ("vXXXX.") prefix...
        */

        uri ++;

        while (isxdigit(*uri & 255))
          uri ++;

        if (*uri != '.')
        {
          *host = '\0';
          return (HTTP_URI_STATUS_BAD_HOSTNAME);
        }

        uri ++;
      }

      uri = http_copy_decode(host, uri, hostlen, "]",
                             decoding & HTTP_URI_CODING_HOSTNAME);

      if (!uri)
      {
        *host = '\0';
        return (HTTP_URI_STATUS_BAD_HOSTNAME);
      }

     /*
      * Validate value...
      */

      if (*uri != ']')
      {
        *host = '\0';
        return (HTTP_URI_STATUS_BAD_HOSTNAME);
      }

      uri ++;

      for (ptr = host; *ptr; ptr ++)
        if (*ptr == '+')
        {
         /*
          * Convert zone separator to % and stop here...
          */

          *ptr = '%';
          break;
        }
        else if (*ptr == '%')
        {
         /*
          * Stop at zone separator (RFC 6874)
          */

          break;
        }
        else if (*ptr != ':' && *ptr != '.' && !isxdigit(*ptr & 255))
        {
          *host = '\0';
          return (HTTP_URI_STATUS_BAD_HOSTNAME);
        }
    }
    else
    {
     /*
      * Validate the hostname or IPv4 address first...
      */

      for (ptr = (char *)uri; *ptr; ptr ++)
        if (strchr(":?/", *ptr))
          break;
        else if (!strchr("abcdefghijklmnopqrstuvwxyz"   /* unreserved */
                         "ABCDEFGHIJKLMNOPQRSTUVWXYZ"   /* unreserved */
                         "0123456789"                   /* unreserved */
                         "-._~"                         /* unreserved */
                         "%"                            /* pct-encoded */
                         "!$&'()*+,;="                  /* sub-delims */
                         "\\", *ptr))                   /* SMB domain */
        {
          *host = '\0';
          return (HTTP_URI_STATUS_BAD_HOSTNAME);
        }

     /*
      * Then copy the hostname or IPv4 address to the buffer...
      */

      uri = http_copy_decode(host, uri, hostlen, ":?/",
                             decoding & HTTP_URI_CODING_HOSTNAME);

      if (!uri)
      {
        *host = '\0';
        return (HTTP_URI_STATUS_BAD_HOSTNAME);
      }
    }

   /*
    * Validate hostname for file scheme - only empty and localhost are
    * acceptable.
    */

    if (!strcmp(scheme, "file") && strcmp(host, "localhost") && host[0])
    {
      *host = '\0';
      return (HTTP_URI_STATUS_BAD_HOSTNAME);
    }

   /*
    * See if we have a port number...
    */

    if (*uri == ':')
    {
     /*
      * Yes, collect the port number...
      */

      if (!isdigit(uri[1] & 255))
      {
        *port = 0;
        return (HTTP_URI_STATUS_BAD_PORT);
      }

      *port = (int)strtol(uri + 1, (char **)&uri, 10);

      if (*port <= 0 || *port > 65535)
      {
        *port = 0;
        return (HTTP_URI_STATUS_BAD_PORT);
      }

      if (*uri != '/' && *uri)
      {
        *port = 0;
        return (HTTP_URI_STATUS_BAD_PORT);
      }
    }
  }

 /*
  * The remaining portion is the resource string...
  */

  if (*uri == '?' || !*uri)
  {
   /*
    * Hostname but no path...
    */

    status    = HTTP_URI_STATUS_MISSING_RESOURCE;
    *resource = '/';

   /*
    * Copy any query string...
    */

    if (*uri == '?')
      uri = http_copy_decode(resource + 1, uri, resourcelen - 1, NULL,
                             decoding & HTTP_URI_CODING_QUERY);
    else
      resource[1] = '\0';
  }
  else
  {
    uri = http_copy_decode(resource, uri, resourcelen, "?",
                           decoding & HTTP_URI_CODING_RESOURCE);

    if (uri && *uri == '?')
    {
     /*
      * Concatenate any query string...
      */

      char *resptr = resource + strlen(resource);

      uri = http_copy_decode(resptr, uri,
                             resourcelen - (int)(resptr - resource), NULL,
                             decoding & HTTP_URI_CODING_QUERY);
    }
  }

  if (!uri)
  {
    *resource = '\0';
    return (HTTP_URI_STATUS_BAD_RESOURCE);
  }

 /*
  * Return the URI separation status...
  */

  return (status);
}


/*
 * '_httpSetDigestAuthString()' - Calculate a Digest authentication response
 *                                using the appropriate RFC 2068/2617/7616
 *                                algorithm.
 */

int                                     /* O - 1 on success, 0 on failure */
_httpSetDigestAuthString(
    http_t     *http,                   /* I - HTTP connection */
    const char *nonce,                  /* I - Nonce value */
    const char *method,                 /* I - HTTP method */
    const char *resource)               /* I - HTTP resource path */
{
  char          kd[65],                 /* Final MD5/SHA-256 digest */
                ha1[65],                /* Hash of username:realm:password */
                ha2[65],                /* Hash of method:request-uri */
                username[HTTP_MAX_VALUE],
                                        /* username:password */
                *password,              /* Pointer to password */
                temp[1024],             /* Temporary string */
                digest[1024];           /* Digest auth data */
  unsigned char hash[32];               /* Hash buffer */
  size_t        hashsize;               /* Size of hash */
  _cups_globals_t *cg = _cupsGlobals(); /* Per-thread globals */


  DEBUG_printf(("2_httpSetDigestAuthString(http=%p, nonce=\"%s\", method=\"%s\", resource=\"%s\")", (void *)http, nonce, method, resource));

  if (nonce && *nonce && strcmp(nonce, http->nonce))
  {
    strlcpy(http->nonce, nonce, sizeof(http->nonce));

    if (nonce == http->nextnonce)
      http->nextnonce[0] = '\0';

    http->nonce_count = 1;
  }
  else
    http->nonce_count ++;

  strlcpy(username, http->userpass, sizeof(username));
  if ((password = strchr(username, ':')) != NULL)
    *password++ = '\0';
  else
    return (0);

  if (http->algorithm[0])
  {
   /*
    * Follow RFC 2617/7616...
    */

    int         i;                      /* Looping var */
    char        cnonce[65];             /* cnonce value */
    const char  *hashalg;               /* Hashing algorithm */

    for (i = 0; i < 64; i ++)
      cnonce[i] = "0123456789ABCDEF"[CUPS_RAND() & 15];
    cnonce[64] = '\0';

    if (!_cups_strcasecmp(http->algorithm, "MD5"))
    {
     /*
      * RFC 2617 Digest with MD5
      */

      if (cg->digestoptions == _CUPS_DIGESTOPTIONS_DENYMD5)
      {
        DEBUG_puts("3_httpSetDigestAuthString: MD5 Digest is disabled.");
        return (0);
      }

      hashalg = "md5";
    }
    else if (!_cups_strcasecmp(http->algorithm, "SHA-256"))
    {
     /*
      * RFC 7616 Digest with SHA-256
      */

      hashalg = "sha2-256";
    }
    else
    {
     /*
      * Some other algorithm we don't support, skip this one...
      */

      return (0);
    }

   /*
    * Calculate digest value...
    */

    /* H(A1) = H(username:realm:password) */
    snprintf(temp, sizeof(temp), "%s:%s:%s", username, http->realm, password);
    hashsize = (size_t)cupsHashData(hashalg, (unsigned char *)temp, strlen(temp), hash, sizeof(hash));
    cupsHashString(hash, hashsize, ha1, sizeof(ha1));

    /* H(A2) = H(method:uri) */
    snprintf(temp, sizeof(temp), "%s:%s", method, resource);
    hashsize = (size_t)cupsHashData(hashalg, (unsigned char *)temp, strlen(temp), hash, sizeof(hash));
    cupsHashString(hash, hashsize, ha2, sizeof(ha2));

    /* KD = H(H(A1):nonce:nc:cnonce:qop:H(A2)) */
    snprintf(temp, sizeof(temp), "%s:%s:%08x:%s:%s:%s", ha1, http->nonce, http->nonce_count, cnonce, "auth", ha2);
    hashsize = (size_t)cupsHashData(hashalg, (unsigned char *)temp, strlen(temp), hash, sizeof(hash));
    cupsHashString(hash, hashsize, kd, sizeof(kd));

   /*
    * Pass the RFC 2617/7616 WWW-Authenticate header...
    */

    if (http->opaque[0])
      snprintf(digest, sizeof(digest), "username=\"%s\", realm=\"%s\", nonce=\"%s\", algorithm=%s, qop=auth, opaque=\"%s\", cnonce=\"%s\", nc=%08x, uri=\"%s\", response=\"%s\"", cupsUser(), http->realm, http->nonce, http->algorithm, http->opaque, cnonce, http->nonce_count, resource, kd);
    else
      snprintf(digest, sizeof(digest), "username=\"%s\", realm=\"%s\", nonce=\"%s\", algorithm=%s, qop=auth, cnonce=\"%s\", nc=%08x, uri=\"%s\", response=\"%s\"", username, http->realm, http->nonce, http->algorithm, cnonce, http->nonce_count, resource, kd);
  }
  else
  {
   /*
    * Use old RFC 2069 Digest method...
    */

    /* H(A1) = H(username:realm:password) */
    snprintf(temp, sizeof(temp), "%s:%s:%s", username, http->realm, password);
    hashsize = (size_t)cupsHashData("md5", (unsigned char *)temp, strlen(temp), hash, sizeof(hash));
    cupsHashString(hash, hashsize, ha1, sizeof(ha1));

    /* H(A2) = H(method:uri) */
    snprintf(temp, sizeof(temp), "%s:%s", method, resource);
    hashsize = (size_t)cupsHashData("md5", (unsigned char *)temp, strlen(temp), hash, sizeof(hash));
    cupsHashString(hash, hashsize, ha2, sizeof(ha2));

    /* KD = H(H(A1):nonce:H(A2)) */
    snprintf(temp, sizeof(temp), "%s:%s:%s", ha1, http->nonce, ha2);
    hashsize = (size_t)cupsHashData("md5", (unsigned char *)temp, strlen(temp), hash, sizeof(hash));
    cupsHashString(hash, hashsize, kd, sizeof(kd));

   /*
    * Pass the old RFC 2069 WWW-Authenticate header...
    */

    snprintf(digest, sizeof(digest), "username=\"%s\", realm=\"%s\", nonce=\"%s\", uri=\"%s\", response=\"%s\"", username, http->realm, http->nonce, resource, kd);
  }

  httpSetAuthString(http, "Digest", digest);

  return (1);
}


/*
 * 'httpStateString()' - Return the string describing a HTTP state value.
 *
 * @since CUPS 2.0/OS 10.10@
 */

const char *                            /* O - State string */
httpStateString(http_state_t state)     /* I - HTTP state value */
{
  if (state < HTTP_STATE_ERROR || state > HTTP_STATE_UNKNOWN_VERSION)
    return ("HTTP_STATE_???");
  else
    return (http_states[state - HTTP_STATE_ERROR]);
}


/*
 * '_httpStatus()' - Return the localized string describing a HTTP status code.
 *
 * The returned string is localized using the passed message catalog.
 */

const char *                            /* O - Localized status string */
_httpStatus(cups_lang_t   *lang,        /* I - Language */
            http_status_t status)       /* I - HTTP status code */
{
  const char    *s;                     /* Status string */


  switch (status)
  {
    case HTTP_STATUS_ERROR :
        s = strerror(errno);
        break;
    case HTTP_STATUS_CONTINUE :
        s = _("Continue");
        break;
    case HTTP_STATUS_SWITCHING_PROTOCOLS :
        s = _("Switching Protocols");
        break;
    case HTTP_STATUS_OK :
        s = _("OK");
        break;
    case HTTP_STATUS_CREATED :
        s = _("Created");
        break;
    case HTTP_STATUS_ACCEPTED :
        s = _("Accepted");
        break;
    case HTTP_STATUS_NO_CONTENT :
        s = _("No Content");
        break;
    case HTTP_STATUS_MOVED_PERMANENTLY :
        s = _("Moved Permanently");
        break;
    case HTTP_STATUS_FOUND :
        s = _("Found");
        break;
    case HTTP_STATUS_SEE_OTHER :
        s = _("See Other");
        break;
    case HTTP_STATUS_NOT_MODIFIED :
        s = _("Not Modified");
        break;
    case HTTP_STATUS_BAD_REQUEST :
        s = _("Bad Request");
        break;
    case HTTP_STATUS_UNAUTHORIZED :
    case HTTP_STATUS_CUPS_AUTHORIZATION_CANCELED :
        s = _("Unauthorized");
        break;
    case HTTP_STATUS_FORBIDDEN :
        s = _("Forbidden");
        break;
    case HTTP_STATUS_NOT_FOUND :
        s = _("Not Found");
        break;
    case HTTP_STATUS_REQUEST_TOO_LARGE :
        s = _("Request Entity Too Large");
        break;
    case HTTP_STATUS_URI_TOO_LONG :
        s = _("URI Too Long");
        break;
    case HTTP_STATUS_UPGRADE_REQUIRED :
        s = _("Upgrade Required");
        break;
    case HTTP_STATUS_NOT_IMPLEMENTED :
        s = _("Not Implemented");
        break;
    case HTTP_STATUS_NOT_SUPPORTED :
        s = _("Not Supported");
        break;
    case HTTP_STATUS_EXPECTATION_FAILED :
        s = _("Expectation Failed");
        break;
    case HTTP_STATUS_SERVICE_UNAVAILABLE :
        s = _("Service Unavailable");
        break;
    case HTTP_STATUS_SERVER_ERROR :
        s = _("Internal Server Error");
        break;
    case HTTP_STATUS_CUPS_PKI_ERROR :
        s = _("SSL/TLS Negotiation Error");
        break;
    case HTTP_STATUS_CUPS_WEBIF_DISABLED :
        s = _("Web Interface is Disabled");
        break;

    default :
        s = _("Unknown");
        break;
  }

  return (_cupsLangString(lang, s));
}


/*
 * 'httpStatus()' - Return a short string describing a HTTP status code.
 *
 * The returned string is localized to the current POSIX locale and is based
 * on the status strings defined in RFC 7231.
 */

const char *                            /* O - Localized status string */
httpStatus(http_status_t status)        /* I - HTTP status code */
{
  _cups_globals_t *cg = _cupsGlobals(); /* Global data */


  if (!cg->lang_default)
    cg->lang_default = cupsLangDefault();

  return (_httpStatus(cg->lang_default, status));
}

/*
 * 'httpURIStatusString()' - Return a string describing a URI status code.
 *
 * @since CUPS 2.0/OS 10.10@
 */

const char *                            /* O - Localized status string */
httpURIStatusString(
    http_uri_status_t status)           /* I - URI status code */
{
  const char    *s;                     /* Status string */
  _cups_globals_t *cg = _cupsGlobals(); /* Global data */


  if (!cg->lang_default)
    cg->lang_default = cupsLangDefault();

  switch (status)
  {
    case HTTP_URI_STATUS_OVERFLOW :
        s = _("URI too large");
        break;
    case HTTP_URI_STATUS_BAD_ARGUMENTS :
        s = _("Bad arguments to function");
        break;
    case HTTP_URI_STATUS_BAD_RESOURCE :
        s = _("Bad resource in URI");
        break;
    case HTTP_URI_STATUS_BAD_PORT :
        s = _("Bad port number in URI");
        break;
    case HTTP_URI_STATUS_BAD_HOSTNAME :
        s = _("Bad hostname/address in URI");
        break;
    case HTTP_URI_STATUS_BAD_USERNAME :
        s = _("Bad username in URI");
        break;
    case HTTP_URI_STATUS_BAD_SCHEME :
        s = _("Bad scheme in URI");
        break;
    case HTTP_URI_STATUS_BAD_URI :
        s = _("Bad/empty URI");
        break;
    case HTTP_URI_STATUS_OK :
        s = _("OK");
        break;
    case HTTP_URI_STATUS_MISSING_SCHEME :
        s = _("Missing scheme in URI");
        break;
    case HTTP_URI_STATUS_UNKNOWN_SCHEME :
        s = _("Unknown scheme in URI");
        break;
    case HTTP_URI_STATUS_MISSING_RESOURCE :
        s = _("Missing resource in URI");
        break;

    default:
        s = _("Unknown");
        break;
  }

  return (_cupsLangString(cg->lang_default, s));
}


#ifndef HAVE_HSTRERROR
/*
 * '_cups_hstrerror()' - hstrerror() emulation function for Solaris and others.
 */

const char *                            /* O - Error string */
_cups_hstrerror(int error)              /* I - Error number */
{
  static const char * const errors[] =  /* Error strings */
                {
                  "OK",
                  "Host not found.",
                  "Try again.",
                  "Unrecoverable lookup error.",
                  "No data associated with name."
                };


  if (error < 0 || error > 4)
    return ("Unknown hostname lookup error.");
  else
    return (errors[error]);
}
#endif /* !HAVE_HSTRERROR */


/*
 * '_httpDecodeURI()' - Percent-decode a HTTP request URI.
 */

char *                                  /* O - Decoded URI or NULL on error */
_httpDecodeURI(char       *dst,         /* I - Destination buffer */
               const char *src,         /* I - Source URI */
               size_t     dstsize)      /* I - Size of destination buffer */
{
  if (http_copy_decode(dst, src, (int)dstsize, NULL, 1))
    return (dst);
  else
    return (NULL);
}


/*
 * '_httpEncodeURI()' - Percent-encode a HTTP request URI.
 */

char *                                  /* O - Encoded URI */
_httpEncodeURI(char       *dst,         /* I - Destination buffer */
               const char *src,         /* I - Source URI */
               size_t     dstsize)      /* I - Size of destination buffer */
{
  http_copy_encode(dst, src, dst + dstsize - 1, NULL, NULL, 1);
  return (dst);
}


/*
 * '_httpResolveURI()' - Resolve a DNS-SD URI.
 */

const char *                            /* O - Resolved URI */
_httpResolveURI(
    const char *uri,                    /* I - DNS-SD URI */
    char       *resolved_uri,           /* I - Buffer for resolved URI */
    size_t     resolved_size,           /* I - Size of URI buffer */
    int        options,                 /* I - Resolve options */
    int        (*cb)(void *context),    /* I - Continue callback function */
    void       *context)                /* I - Context pointer for callback */
{
  char                  scheme[32],     /* URI components... */
                        userpass[256],
                        hostname[1024],
                        resource[1024];
  int                   port;
#ifdef DEBUG
  http_uri_status_t     status;         /* URI decode status */
#endif /* DEBUG */


  DEBUG_printf(("_httpResolveURI(uri=\"%s\", resolved_uri=%p, resolved_size=" CUPS_LLFMT ", options=0x%x, cb=%p, context=%p)", uri, (void *)resolved_uri, CUPS_LLCAST resolved_size, options, (void *)cb, context));

 /*
  * Get the device URI...
  */

#ifdef DEBUG
  if ((status = httpSeparateURI(HTTP_URI_CODING_ALL, uri, scheme,
                                sizeof(scheme), userpass, sizeof(userpass),
                                hostname, sizeof(hostname), &port, resource,
                                sizeof(resource))) < HTTP_URI_STATUS_OK)
#else
  if (httpSeparateURI(HTTP_URI_CODING_ALL, uri, scheme,
                      sizeof(scheme), userpass, sizeof(userpass),
                      hostname, sizeof(hostname), &port, resource,
                      sizeof(resource)) < HTTP_URI_STATUS_OK)
#endif /* DEBUG */
  {
    if (options & _HTTP_RESOLVE_STDERR)
      _cupsLangPrintFilter(stderr, "ERROR", _("Bad device-uri \"%s\"."), uri);

    DEBUG_printf(("2_httpResolveURI: httpSeparateURI returned %d!", status));
    DEBUG_puts("2_httpResolveURI: Returning NULL");
    return (NULL);
  }

 /*
  * Resolve it as needed...
  */

  if (strstr(hostname, "._tcp"))
  {
#if defined(HAVE_DNSSD) || defined(HAVE_AVAHI)
    char                *regtype,       /* Pointer to type in hostname */
                        *domain,        /* Pointer to domain in hostname */
                        *uuid,          /* Pointer to UUID in URI */
                        *uuidend;       /* Pointer to end of UUID in URI */
    _http_uribuf_t      uribuf;         /* URI buffer */
    int                 offline = 0;    /* offline-report state set? */
#  ifdef HAVE_DNSSD
    DNSServiceRef       ref,            /* DNS-SD master service reference */
                        domainref = NULL,/* DNS-SD service reference for domain */
                        ippref = NULL,  /* DNS-SD service reference for network IPP */
                        ippsref = NULL, /* DNS-SD service reference for network IPPS */
                        localref;       /* DNS-SD service reference for .local */
    int                 extrasent = 0;  /* Send the domain/IPP/IPPS resolves? */
#    ifdef HAVE_POLL
    struct pollfd       polldata;       /* Polling data */
#    else /* select() */
    fd_set              input_set;      /* Input set for select() */
    struct timeval      stimeout;       /* Timeout value for select() */
#    endif /* HAVE_POLL */
#  elif defined(HAVE_AVAHI)
    AvahiClient         *client;        /* Client information */
    int                 error;          /* Status */
#  endif /* HAVE_DNSSD */

    if (options & _HTTP_RESOLVE_STDERR)
      fprintf(stderr, "DEBUG: Resolving \"%s\"...\n", hostname);

   /*
    * Separate the hostname into service name, registration type, and domain...
    */

    for (regtype = strstr(hostname, "._tcp") - 2;
         regtype > hostname;
         regtype --)
      if (regtype[0] == '.' && regtype[1] == '_')
      {
       /*
        * Found ._servicetype in front of ._tcp...
        */

        *regtype++ = '\0';
        break;
      }

    if (regtype <= hostname)
    {
      DEBUG_puts("2_httpResolveURI: Bad hostname, returning NULL");
      return (NULL);
    }

    for (domain = strchr(regtype, '.');
         domain;
         domain = strchr(domain + 1, '.'))
      if (domain[1] != '_')
        break;

    if (domain)
      *domain++ = '\0';

    if ((uuid = strstr(resource, "?uuid=")) != NULL)
    {
      *uuid = '\0';
      uuid  += 6;
      if ((uuidend = strchr(uuid, '&')) != NULL)
        *uuidend = '\0';
    }

    resolved_uri[0] = '\0';

    uribuf.buffer   = resolved_uri;
    uribuf.bufsize  = resolved_size;
    uribuf.options  = options;
    uribuf.resource = resource;
    uribuf.uuid     = uuid;

    DEBUG_printf(("2_httpResolveURI: Resolving hostname=\"%s\", regtype=\"%s\", "
                  "domain=\"%s\"\n", hostname, regtype, domain));
    if (options & _HTTP_RESOLVE_STDERR)
    {
      fputs("STATE: +connecting-to-device\n", stderr);
      fprintf(stderr, "DEBUG: Resolving \"%s\", regtype=\"%s\", "
                      "domain=\"local.\"...\n", hostname, regtype);
    }

    uri = NULL;

#  ifdef HAVE_DNSSD
    if (DNSServiceCreateConnection(&ref) == kDNSServiceErr_NoError)
    {
      uint32_t myinterface = kDNSServiceInterfaceIndexAny;
                                        /* Lookup on any interface */

      if (!strcmp(scheme, "ippusb"))
        myinterface = kDNSServiceInterfaceIndexLocalOnly;

      localref = ref;
      if (DNSServiceResolve(&localref,
                            kDNSServiceFlagsShareConnection, myinterface,
                            hostname, regtype, "local.", http_resolve_cb,
                            &uribuf) == kDNSServiceErr_NoError)
      {
        int     fds;                    /* Number of ready descriptors */
        time_t  timeout,                /* Poll timeout */
                start_time = time(NULL),/* Start time */
                end_time = start_time + 90;
                                        /* End time */

        while (time(NULL) < end_time)
        {
          if (options & _HTTP_RESOLVE_STDERR)
            _cupsLangPrintFilter(stderr, "INFO", _("Looking for printer."));

          if (cb && !(*cb)(context))
          {
            DEBUG_puts("2_httpResolveURI: callback returned 0 (stop)");
            break;
          }

         /*
          * Wakeup every 2 seconds to emit a "looking for printer" message...
          */

          if ((timeout = end_time - time(NULL)) > 2)
            timeout = 2;

#    ifdef HAVE_POLL
          polldata.fd     = DNSServiceRefSockFD(ref);
          polldata.events = POLLIN;

          fds = poll(&polldata, 1, (int)(1000 * timeout));

#    else /* select() */
          FD_ZERO(&input_set);
          FD_SET(DNSServiceRefSockFD(ref), &input_set);

#      ifdef _WIN32
          stimeout.tv_sec  = (long)timeout;
#      else
          stimeout.tv_sec  = timeout;
#      endif /* _WIN32 */
          stimeout.tv_usec = 0;

          fds = select(DNSServiceRefSockFD(ref)+1, &input_set, NULL, NULL,
                       &stimeout);
#    endif /* HAVE_POLL */

          if (fds < 0)
          {
            if (errno != EINTR && errno != EAGAIN)
            {
              DEBUG_printf(("2_httpResolveURI: poll error: %s", strerror(errno)));
              break;
            }
          }
          else if (fds == 0)
          {
           /*
            * Wait 2 seconds for a response to the local resolve; if nothing
            * comes in, do an additional domain resolution...
            */

            if (extrasent == 0 && domain && _cups_strcasecmp(domain, "local."))
            {
              if (options & _HTTP_RESOLVE_STDERR)
                fprintf(stderr,
                        "DEBUG: Resolving \"%s\", regtype=\"%s\", "
                        "domain=\"%s\"...\n", hostname, regtype,
                        domain ? domain : "");

              domainref = ref;
              if (DNSServiceResolve(&domainref,
                                    kDNSServiceFlagsShareConnection,
                                    myinterface, hostname, regtype, domain,
                                    http_resolve_cb,
                                    &uribuf) == kDNSServiceErr_NoError)
                extrasent = 1;
            }
            else if (extrasent == 0 && !strcmp(scheme, "ippusb"))
            {
              if (options & _HTTP_RESOLVE_STDERR)
                fprintf(stderr, "DEBUG: Resolving \"%s\", regtype=\"_ipps._tcp\", domain=\"local.\"...\n", hostname);

              ippsref = ref;
              if (DNSServiceResolve(&ippsref,
                                    kDNSServiceFlagsShareConnection,
                                    kDNSServiceInterfaceIndexAny, hostname,
                                    "_ipps._tcp", domain, http_resolve_cb,
                                    &uribuf) == kDNSServiceErr_NoError)
                extrasent = 1;
            }
            else if (extrasent == 1 && !strcmp(scheme, "ippusb"))
            {
              if (options & _HTTP_RESOLVE_STDERR)
                fprintf(stderr, "DEBUG: Resolving \"%s\", regtype=\"_ipp._tcp\", domain=\"local.\"...\n", hostname);

              ippref = ref;
              if (DNSServiceResolve(&ippref,
                                    kDNSServiceFlagsShareConnection,
                                    kDNSServiceInterfaceIndexAny, hostname,
                                    "_ipp._tcp", domain, http_resolve_cb,
                                    &uribuf) == kDNSServiceErr_NoError)
                extrasent = 2;
            }

           /*
            * If it hasn't resolved within 5 seconds set the offline-report
            * printer-state-reason...
            */

            if ((options & _HTTP_RESOLVE_STDERR) && offline == 0 &&
                time(NULL) > (start_time + 5))
            {
              fputs("STATE: +offline-report\n", stderr);
              offline = 1;
            }
          }
          else
          {
            if (DNSServiceProcessResult(ref) == kDNSServiceErr_NoError &&
                resolved_uri[0])
            {
              uri = resolved_uri;
              break;
            }
          }
        }

        if (extrasent)
        {
          if (domainref)
            DNSServiceRefDeallocate(domainref);
          if (ippref)
            DNSServiceRefDeallocate(ippref);
          if (ippsref)
            DNSServiceRefDeallocate(ippsref);
        }

        DNSServiceRefDeallocate(localref);
      }

      DNSServiceRefDeallocate(ref);
    }
#  else /* HAVE_AVAHI */
    if ((uribuf.poll = avahi_simple_poll_new()) != NULL)
    {
      avahi_simple_poll_set_func(uribuf.poll, http_poll_cb, NULL);

      if ((client = avahi_client_new(avahi_simple_poll_get(uribuf.poll),
                                      0, http_client_cb,
                                      &uribuf, &error)) != NULL)
      {
        if (avahi_service_resolver_new(client, AVAHI_IF_UNSPEC,
                                       AVAHI_PROTO_UNSPEC, hostname,
                                       regtype, "local.", AVAHI_PROTO_UNSPEC, 0,
                                       http_resolve_cb, &uribuf) != NULL)
        {
          time_t        start_time = time(NULL),
                                        /* Start time */
                        end_time = start_time + 90;
                                        /* End time */
          int           pstatus;        /* Poll status */

          pstatus = avahi_simple_poll_iterate(uribuf.poll, 2000);

          if (pstatus == 0 && !resolved_uri[0] && domain &&
              _cups_strcasecmp(domain, "local."))
          {
           /*
            * Resolve for .local hasn't returned anything, try the listed
            * domain...
            */

            avahi_service_resolver_new(client, AVAHI_IF_UNSPEC,
                                       AVAHI_PROTO_UNSPEC, hostname,
                                       regtype, domain, AVAHI_PROTO_UNSPEC, 0,
                                       http_resolve_cb, &uribuf);
          }

          while (!pstatus && !resolved_uri[0] && time(NULL) < end_time)
          {
            if ((pstatus = avahi_simple_poll_iterate(uribuf.poll, 2000)) != 0)
              break;

           /*
            * If it hasn't resolved within 5 seconds set the offline-report
            * printer-state-reason...
            */

            if ((options & _HTTP_RESOLVE_STDERR) && offline == 0 &&
                time(NULL) > (start_time + 5))
            {
              fputs("STATE: +offline-report\n", stderr);
              offline = 1;
            }
          }

         /*
          * Collect the result (if we got one).
          */

          if (resolved_uri[0])
            uri = resolved_uri;
        }

        avahi_client_free(client);
      }

      avahi_simple_poll_free(uribuf.poll);
    }
#  endif /* HAVE_DNSSD */

    if (options & _HTTP_RESOLVE_STDERR)
    {
      if (uri)
      {
        fprintf(stderr, "DEBUG: Resolved as \"%s\"...\n", uri);
        fputs("STATE: -connecting-to-device,offline-report\n", stderr);
      }
      else
      {
        fputs("DEBUG: Unable to resolve URI\n", stderr);
        fputs("STATE: -connecting-to-device\n", stderr);
      }
    }

#else /* HAVE_DNSSD || HAVE_AVAHI */
   /*
    * No DNS-SD support...
    */

    uri = NULL;
#endif /* HAVE_DNSSD || HAVE_AVAHI */

    if ((options & _HTTP_RESOLVE_STDERR) && !uri)
      _cupsLangPrintFilter(stderr, "INFO", _("Unable to find printer."));
  }
  else
  {
   /*
    * Nothing more to do...
    */

    strlcpy(resolved_uri, uri, resolved_size);
    uri = resolved_uri;
  }

  DEBUG_printf(("2_httpResolveURI: Returning \"%s\"", uri));

  return (uri);
}


#ifdef HAVE_AVAHI
/*
 * 'http_client_cb()' - Client callback for resolving URI.
 */

static void
http_client_cb(
    AvahiClient      *client,           /* I - Client information */
    AvahiClientState state,             /* I - Current state */
    void             *context)          /* I - Pointer to URI buffer */
{
  DEBUG_printf(("7http_client_cb(client=%p, state=%d, context=%p)", client,
                state, context));

 /*
  * If the connection drops, quit.
  */

  if (state == AVAHI_CLIENT_FAILURE)
  {
    _http_uribuf_t *uribuf = (_http_uribuf_t *)context;
                                        /* URI buffer */

    avahi_simple_poll_quit(uribuf->poll);
  }
}
#endif /* HAVE_AVAHI */


/*
 * 'http_copy_decode()' - Copy and decode a URI.
 */

static const char *                     /* O - New source pointer or NULL on error */
http_copy_decode(char       *dst,       /* O - Destination buffer */
                 const char *src,       /* I - Source pointer */
                 int        dstsize,    /* I - Destination size */
                 const char *term,      /* I - Terminating characters */
                 int        decode)     /* I - Decode %-encoded values */
{
  char  *ptr,                           /* Pointer into buffer */
        *end;                           /* End of buffer */
  int   quoted;                         /* Quoted character */


 /*
  * Copy the src to the destination until we hit a terminating character
  * or the end of the string.
  */

  for (ptr = dst, end = dst + dstsize - 1;
       *src && (!term || !strchr(term, *src));
       src ++)
    if (ptr < end)
    {
      if (*src == '%' && decode)
      {
        if (isxdigit(src[1] & 255) && isxdigit(src[2] & 255))
        {
         /*
          * Grab a hex-encoded character...
          */

          src ++;
          if (isalpha(*src))
            quoted = (tolower(*src) - 'a' + 10) << 4;
          else
            quoted = (*src - '0') << 4;

          src ++;
          if (isalpha(*src))
            quoted |= tolower(*src) - 'a' + 10;
          else
            quoted |= *src - '0';

          *ptr++ = (char)quoted;
        }
        else
        {
         /*
          * Bad hex-encoded character...
          */

          *ptr = '\0';
          return (NULL);
        }
      }
      else if ((*src & 255) <= 0x20 || (*src & 255) >= 0x7f)
      {
        *ptr = '\0';
        return (NULL);
      }
      else
        *ptr++ = *src;
    }

  *ptr = '\0';

  return (src);
}


/*
 * 'http_copy_encode()' - Copy and encode a URI.
 */

static char *                           /* O - End of current URI */
http_copy_encode(char       *dst,       /* O - Destination buffer */
                 const char *src,       /* I - Source pointer */
                 char       *dstend,    /* I - End of destination buffer */
                 const char *reserved,  /* I - Extra reserved characters */
                 const char *term,      /* I - Terminating characters */
                 int        encode)     /* I - %-encode reserved chars? */
{
  static const char hex[] = "0123456789ABCDEF";


  while (*src && dst < dstend)
  {
    if (term && *src == *term)
      return (dst);

    if (encode && (*src == '%' || *src <= ' ' || *src & 128 ||
                   (reserved && strchr(reserved, *src))))
    {
     /*
      * Hex encode reserved characters...
      */

      if ((dst + 2) >= dstend)
        break;

      *dst++ = '%';
      *dst++ = hex[(*src >> 4) & 15];
      *dst++ = hex[*src & 15];

      src ++;
    }
    else
      *dst++ = *src++;
  }

  *dst = '\0';

  if (*src)
    return (NULL);
  else
    return (dst);
}


#ifdef HAVE_DNSSD
/*
 * 'http_resolve_cb()' - Build a device URI for the given service name.
 */

static void DNSSD_API
http_resolve_cb(
    DNSServiceRef       sdRef,          /* I - Service reference */
    DNSServiceFlags     flags,          /* I - Results flags */
    uint32_t            interfaceIndex, /* I - Interface number */
    DNSServiceErrorType errorCode,      /* I - Error, if any */
    const char          *fullName,      /* I - Full service name */
    const char          *hostTarget,    /* I - Hostname */
    uint16_t            port,           /* I - Port number */
    uint16_t            txtLen,         /* I - Length of TXT record */
    const unsigned char *txtRecord,     /* I - TXT record data */
    void                *context)       /* I - Pointer to URI buffer */
{
  _http_uribuf_t        *uribuf = (_http_uribuf_t *)context;
                                        /* URI buffer */
  const char            *scheme,        /* URI scheme */
                        *hostptr,       /* Pointer into hostTarget */
                        *reskey,        /* "rp" or "rfo" */
                        *resdefault;    /* Default path */
  char                  resource[257],  /* Remote path */
                        fqdn[256];      /* FQDN of the .local name */
  const void            *value;         /* Value from TXT record */
  uint8_t               valueLen;       /* Length of value */


  DEBUG_printf(("4http_resolve_cb(sdRef=%p, flags=%x, interfaceIndex=%u, errorCode=%d, fullName=\"%s\", hostTarget=\"%s\", port=%u, txtLen=%u, txtRecord=%p, context=%p)", (void *)sdRef, flags, interfaceIndex, errorCode, fullName, hostTarget, port, txtLen, (void *)txtRecord, context));

 /*
  * If we have a UUID, compare it...
  */

  if (uribuf->uuid &&
      (value = TXTRecordGetValuePtr(txtLen, txtRecord, "UUID",
                                    &valueLen)) != NULL)
  {
    char        uuid[256];              /* UUID value */

    memcpy(uuid, value, valueLen);
    uuid[valueLen] = '\0';

    if (_cups_strcasecmp(uuid, uribuf->uuid))
    {
      if (uribuf->options & _HTTP_RESOLVE_STDERR)
        fprintf(stderr, "DEBUG: Found UUID %s, looking for %s.", uuid,
                uribuf->uuid);

      DEBUG_printf(("5http_resolve_cb: Found UUID %s, looking for %s.", uuid,
                    uribuf->uuid));
      return;
    }
  }

 /*
  * Figure out the scheme from the full name...
  */

  if (strstr(fullName, "._ipps") || strstr(fullName, "._ipp-tls"))
    scheme = "ipps";
  else if (strstr(fullName, "._ipp") || strstr(fullName, "._fax-ipp"))
    scheme = "ipp";
  else if (strstr(fullName, "._http."))
    scheme = "http";
  else if (strstr(fullName, "._https."))
    scheme = "https";
  else if (strstr(fullName, "._printer."))
    scheme = "lpd";
  else if (strstr(fullName, "._pdl-datastream."))
    scheme = "socket";
  else
    scheme = "riousbprint";

 /*
  * Extract the "remote printer" key from the TXT record...
  */

  if ((uribuf->options & _HTTP_RESOLVE_FAXOUT) &&
      (!strcmp(scheme, "ipp") || !strcmp(scheme, "ipps")) &&
      !TXTRecordGetValuePtr(txtLen, txtRecord, "printer-type", &valueLen))
  {
    reskey     = "rfo";
    resdefault = "/ipp/faxout";
  }
  else
  {
    reskey     = "rp";
    resdefault = "/";
  }

  if ((value = TXTRecordGetValuePtr(txtLen, txtRecord, reskey,
                                    &valueLen)) != NULL)
  {
    if (((char *)value)[0] == '/')
    {
     /*
      * Value (incorrectly) has a leading slash already...
      */

      memcpy(resource, value, valueLen);
      resource[valueLen] = '\0';
    }
    else
    {
     /*
      * Convert to resource by concatenating with a leading "/"...
      */

      resource[0] = '/';
      memcpy(resource + 1, value, valueLen);
      resource[valueLen + 1] = '\0';
    }
  }
  else
  {
   /*
    * Use the default value...
    */

    strlcpy(resource, resdefault, sizeof(resource));
  }

 /*
  * Lookup the FQDN if needed...
  */

  if ((uribuf->options & _HTTP_RESOLVE_FQDN) &&
      (hostptr = hostTarget + strlen(hostTarget) - 7) > hostTarget &&
      !_cups_strcasecmp(hostptr, ".local."))
  {
   /*
    * OK, we got a .local name but the caller needs a real domain.  Start by
    * getting the IP address of the .local name and then do reverse-lookups...
    */

    http_addrlist_t     *addrlist,      /* List of addresses */
                        *addr;          /* Current address */

    DEBUG_printf(("5http_resolve_cb: Looking up \"%s\".", hostTarget));

    snprintf(fqdn, sizeof(fqdn), "%d", ntohs(port));
    if ((addrlist = httpAddrGetList(hostTarget, AF_UNSPEC, fqdn)) != NULL)
    {
      for (addr = addrlist; addr; addr = addr->next)
      {
        int error = getnameinfo(&(addr->addr.addr), (socklen_t)httpAddrLength(&(addr->addr)), fqdn, sizeof(fqdn), NULL, 0, NI_NAMEREQD);

        if (!error)
        {
          DEBUG_printf(("5http_resolve_cb: Found \"%s\".", fqdn));

          if ((hostptr = fqdn + strlen(fqdn) - 6) <= fqdn ||
              _cups_strcasecmp(hostptr, ".local"))
          {
            hostTarget = fqdn;
            break;
          }
        }
#ifdef DEBUG
        else
          DEBUG_printf(("5http_resolve_cb: \"%s\" did not resolve: %d",
                        httpAddrString(&(addr->addr), fqdn, sizeof(fqdn)),
                        error));
#endif /* DEBUG */
      }

      httpAddrFreeList(addrlist);
    }
  }

 /*
  * Assemble the final device URI...
  */

  if ((!strcmp(scheme, "ipp") || !strcmp(scheme, "ipps")) &&
      !strcmp(uribuf->resource, "/cups"))
    httpAssembleURIf(HTTP_URI_CODING_ALL, uribuf->buffer, (int)uribuf->bufsize, scheme, NULL, hostTarget, ntohs(port), "%s?snmp=false", resource);
  else
    httpAssembleURI(HTTP_URI_CODING_ALL, uribuf->buffer, (int)uribuf->bufsize, scheme, NULL, hostTarget, ntohs(port), resource);

  DEBUG_printf(("5http_resolve_cb: Resolved URI is \"%s\"...", uribuf->buffer));
}

#elif defined(HAVE_AVAHI)
/*
 * 'http_poll_cb()' - Wait for input on the specified file descriptors.
 *
 * Note: This function is needed because avahi_simple_poll_iterate is broken
 *       and always uses a timeout of 0 (!) milliseconds.
 *       (Avahi Ticket #364)
 *
 * @private@
 */

static int                              /* O - Number of file descriptors matching */
http_poll_cb(
    struct pollfd *pollfds,             /* I - File descriptors */
    unsigned int  num_pollfds,          /* I - Number of file descriptors */
    int           timeout,              /* I - Timeout in milliseconds (used) */
    void          *context)             /* I - User data (unused) */
{
  (void)timeout;
  (void)context;

  return (poll(pollfds, num_pollfds, 2000));
}


/*
 * 'http_resolve_cb()' - Build a device URI for the given service name.
 */

static void
http_resolve_cb(
    AvahiServiceResolver   *resolver,   /* I - Resolver (unused) */
    AvahiIfIndex           interface,   /* I - Interface index (unused) */
    AvahiProtocol          protocol,    /* I - Network protocol (unused) */
    AvahiResolverEvent     event,       /* I - Event (found, etc.) */
    const char             *name,       /* I - Service name */
    const char             *type,       /* I - Registration type */
    const char             *domain,     /* I - Domain (unused) */
    const char             *hostTarget, /* I - Hostname */
    const AvahiAddress     *address,    /* I - Address (unused) */
    uint16_t               port,        /* I - Port number */
    AvahiStringList        *txt,        /* I - TXT record */
    AvahiLookupResultFlags flags,       /* I - Lookup flags (unused) */
    void                   *context)    /* I - Pointer to URI buffer */
{
  _http_uribuf_t        *uribuf = (_http_uribuf_t *)context;
                                        /* URI buffer */
  const char            *scheme,        /* URI scheme */
                        *hostptr,       /* Pointer into hostTarget */
                        *reskey,        /* "rp" or "rfo" */
                        *resdefault;    /* Default path */
  char                  resource[257],  /* Remote path */
                        fqdn[256];      /* FQDN of the .local name */
  AvahiStringList       *pair;          /* Current TXT record key/value pair */
  char                  *value;         /* Value for "rp" key */
  size_t                valueLen = 0;   /* Length of "rp" key */


  DEBUG_printf(("4http_resolve_cb(resolver=%p, "
                "interface=%d, protocol=%d, event=%d, name=\"%s\", "
                "type=\"%s\", domain=\"%s\", hostTarget=\"%s\", address=%p, "
                "port=%d, txt=%p, flags=%d, context=%p)",
                resolver, interface, protocol, event, name, type, domain,
                hostTarget, address, port, txt, flags, context));

  if (event != AVAHI_RESOLVER_FOUND)
  {
    avahi_service_resolver_free(resolver);
    avahi_simple_poll_quit(uribuf->poll);
    return;
  }

 /*
  * If we have a UUID, compare it...
  */

  if (uribuf->uuid && (pair = avahi_string_list_find(txt, "UUID")) != NULL)
  {
    char        uuid[256];              /* UUID value */

    avahi_string_list_get_pair(pair, NULL, &value, &valueLen);

    memcpy(uuid, value, valueLen);
    uuid[valueLen] = '\0';

    if (_cups_strcasecmp(uuid, uribuf->uuid))
    {
      if (uribuf->options & _HTTP_RESOLVE_STDERR)
        fprintf(stderr, "DEBUG: Found UUID %s, looking for %s.", uuid,
                uribuf->uuid);

      DEBUG_printf(("5http_resolve_cb: Found UUID %s, looking for %s.", uuid,
                    uribuf->uuid));
      return;
    }
  }

 /*
  * Figure out the scheme from the full name...
  */

  if (strstr(type, "_ipp."))
    scheme = "ipp";
  else if (strstr(type, "_printer."))
    scheme = "lpd";
  else if (strstr(type, "_pdl-datastream."))
    scheme = "socket";
  else
    scheme = "riousbprint";

  if (!strncmp(type, "_ipps.", 6) || !strncmp(type, "_ipp-tls.", 9))
    scheme = "ipps";
  else if (!strncmp(type, "_ipp.", 5) || !strncmp(type, "_fax-ipp.", 9))
    scheme = "ipp";
  else if (!strncmp(type, "_http.", 6))
    scheme = "http";
  else if (!strncmp(type, "_https.", 7))
    scheme = "https";
  else if (!strncmp(type, "_printer.", 9))
    scheme = "lpd";
  else if (!strncmp(type, "_pdl-datastream.", 16))
    scheme = "socket";
  else
  {
    avahi_service_resolver_free(resolver);
    avahi_simple_poll_quit(uribuf->poll);
    return;
  }

 /*
  * Extract the remote resource key from the TXT record...
  */

  if ((uribuf->options & _HTTP_RESOLVE_FAXOUT) &&
      (!strcmp(scheme, "ipp") || !strcmp(scheme, "ipps")) &&
      !avahi_string_list_find(txt, "printer-type"))
  {
    reskey     = "rfo";
    resdefault = "/ipp/faxout";
  }
  else
  {
    reskey     = "rp";
    resdefault = "/";
  }

  if ((pair = avahi_string_list_find(txt, reskey)) != NULL)
  {
    avahi_string_list_get_pair(pair, NULL, &value, &valueLen);

    if (value[0] == '/')
    {
     /*
      * Value (incorrectly) has a leading slash already...
      */

      memcpy(resource, value, valueLen);
      resource[valueLen] = '\0';
    }
    else
    {
     /*
      * Convert to resource by concatenating with a leading "/"...
      */

      resource[0] = '/';
      memcpy(resource + 1, value, valueLen);
      resource[valueLen + 1] = '\0';
    }
  }
  else
  {
   /*
    * Use the default value...
    */

    strlcpy(resource, resdefault, sizeof(resource));
  }

 /*
  * Lookup the FQDN if needed...
  */

  if ((uribuf->options & _HTTP_RESOLVE_FQDN) &&
      (hostptr = hostTarget + strlen(hostTarget) - 6) > hostTarget &&
      !_cups_strcasecmp(hostptr, ".local"))
  {
   /*
    * OK, we got a .local name but the caller needs a real domain.  Start by
    * getting the IP address of the .local name and then do reverse-lookups...
    */

    http_addrlist_t     *addrlist,      /* List of addresses */
                        *addr;          /* Current address */

    DEBUG_printf(("5http_resolve_cb: Looking up \"%s\".", hostTarget));

    snprintf(fqdn, sizeof(fqdn), "%d", ntohs(port));
    if ((addrlist = httpAddrGetList(hostTarget, AF_UNSPEC, fqdn)) != NULL)
    {
      for (addr = addrlist; addr; addr = addr->next)
      {
        int error = getnameinfo(&(addr->addr.addr), (socklen_t)httpAddrLength(&(addr->addr)), fqdn, sizeof(fqdn), NULL, 0, NI_NAMEREQD);

        if (!error)
        {
          DEBUG_printf(("5http_resolve_cb: Found \"%s\".", fqdn));

          if ((hostptr = fqdn + strlen(fqdn) - 6) <= fqdn ||
              _cups_strcasecmp(hostptr, ".local"))
          {
            hostTarget = fqdn;
            break;
          }
        }
#ifdef DEBUG
        else
          DEBUG_printf(("5http_resolve_cb: \"%s\" did not resolve: %d",
                        httpAddrString(&(addr->addr), fqdn, sizeof(fqdn)),
                        error));
#endif /* DEBUG */
      }

      httpAddrFreeList(addrlist);
    }
  }

 /*
  * Assemble the final device URI using the resolved hostname...
  */

  httpAssembleURI(HTTP_URI_CODING_ALL, uribuf->buffer, (int)uribuf->bufsize, scheme,
                  NULL, hostTarget, port, resource);
  DEBUG_printf(("5http_resolve_cb: Resolved URI is \"%s\".", uribuf->buffer));

  avahi_simple_poll_quit(uribuf->poll);
}
#endif /* HAVE_DNSSD */