Source

gevent / c-ares / ares_getnameinfo.c

Full commit
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427

/* Copyright 2005 by Dominick Meglio
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting
 * documentation, and that the name of M.I.T. not be used in
 * advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is"
 * without express or implied warranty.
 */
#include "ares_setup.h"

#ifdef HAVE_GETSERVBYPORT_R
#  if !defined(GETSERVBYPORT_R_ARGS) || \
     (GETSERVBYPORT_R_ARGS < 4) || (GETSERVBYPORT_R_ARGS > 6)
#    error "you MUST specifiy a valid number of arguments for getservbyport_r"
#  endif
#endif

#ifdef HAVE_SYS_SOCKET_H
#  include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#  include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
#  include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#  include <arpa/inet.h>
#endif
#ifdef HAVE_ARPA_NAMESER_H
#  include <arpa/nameser.h>
#else
#  include "nameser.h"
#endif
#ifdef HAVE_ARPA_NAMESER_COMPAT_H
#  include <arpa/nameser_compat.h>
#endif

#ifdef HAVE_NET_IF_H
#include <net/if.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "ares.h"
#include "ares_ipv6.h"
#include "inet_ntop.h"
#include "ares_nowarn.h"
#include "ares_private.h"

struct nameinfo_query {
  ares_nameinfo_callback callback;
  void *arg;
  union {
    struct sockaddr_in addr4;
    struct sockaddr_in6 addr6;
  } addr;
  int family;
  int flags;
  int timeouts;
};

#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
#define IPBUFSIZ \
        (sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255") + IF_NAMESIZE)
#else
#define IPBUFSIZ \
        (sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"))
#endif

static void nameinfo_callback(void *arg, int status, int timeouts,
                              struct hostent *host);
static char *lookup_service(unsigned short port, int flags,
                            char *buf, size_t buflen);
#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
static void append_scopeid(struct sockaddr_in6 *addr6, unsigned int scopeid,
                           char *buf, size_t buflen);
#endif
static char *ares_striendstr(const char *s1, const char *s2);

void ares_getnameinfo(ares_channel channel, const struct sockaddr *sa,
                      ares_socklen_t salen,
                      int flags, ares_nameinfo_callback callback, void *arg)
{
  struct sockaddr_in *addr = NULL;
  struct sockaddr_in6 *addr6 = NULL;
  struct nameinfo_query *niquery;
  unsigned int port = 0;

  /* Validate socket address family and length */
  if ((sa->sa_family == AF_INET) &&
      (salen == sizeof(struct sockaddr_in)))
    {
      addr = (struct sockaddr_in *)sa;
      port = addr->sin_port;
    }
  else if ((sa->sa_family == AF_INET6) &&
           (salen == sizeof(struct sockaddr_in6)))
    {
      addr6 = (struct sockaddr_in6 *)sa;
      port = addr6->sin6_port;
    }
  else
    {
      callback(arg, ARES_ENOTIMP, 0, NULL, NULL);
      return;
    }

  /* If neither, assume they want a host */
  if (!(flags & ARES_NI_LOOKUPSERVICE) && !(flags & ARES_NI_LOOKUPHOST))
    flags |= ARES_NI_LOOKUPHOST;

  /* All they want is a service, no need for DNS */
  if ((flags & ARES_NI_LOOKUPSERVICE) && !(flags & ARES_NI_LOOKUPHOST))
    {
      char buf[33], *service;

      service = lookup_service((unsigned short)(port & 0xffff),
                               flags, buf, sizeof(buf));
      callback(arg, ARES_SUCCESS, 0, NULL, service);
      return;
    }

  /* They want a host lookup */
  if ((flags & ARES_NI_LOOKUPHOST))
    {
     /* A numeric host can be handled without DNS */
     if ((flags & ARES_NI_NUMERICHOST))
      {
        char ipbuf[IPBUFSIZ];
        char srvbuf[33];
        char *service = NULL;
        ipbuf[0] = 0;

        /* Specifying not to lookup a host, but then saying a host
         * is required has to be illegal.
         */
        if (flags & ARES_NI_NAMEREQD)
          {
            callback(arg, ARES_EBADFLAGS, 0, NULL, NULL);
            return;
          }
        if (salen == sizeof(struct sockaddr_in6))
          {
            ares_inet_ntop(AF_INET6, &addr6->sin6_addr, ipbuf, IPBUFSIZ);
            /* If the system supports scope IDs, use it */
#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
            append_scopeid(addr6, flags, ipbuf, sizeof(ipbuf));
#endif
          }
        else
          {
            ares_inet_ntop(AF_INET, &addr->sin_addr, ipbuf, IPBUFSIZ);
          }
        /* They also want a service */
        if (flags & ARES_NI_LOOKUPSERVICE)
          service = lookup_service((unsigned short)(port & 0xffff),
                                   flags, srvbuf, sizeof(srvbuf));
        callback(arg, ARES_SUCCESS, 0, ipbuf, service);
        return;
      }
    /* This is where a DNS lookup becomes necessary */
    else
      {
        niquery = malloc(sizeof(struct nameinfo_query));
        if (!niquery)
          {
            callback(arg, ARES_ENOMEM, 0, NULL, NULL);
            return;
          }
        niquery->callback = callback;
        niquery->arg = arg;
        niquery->flags = flags;
        niquery->timeouts = 0;
        if (sa->sa_family == AF_INET)
          {
            niquery->family = AF_INET;
            memcpy(&niquery->addr.addr4, addr, sizeof(struct sockaddr_in));
            ares_gethostbyaddr(channel, &addr->sin_addr,
                               sizeof(struct in_addr), AF_INET,
                               nameinfo_callback, niquery);
          }
        else
          {
            niquery->family = AF_INET6;
            memcpy(&niquery->addr.addr6, addr6, sizeof(struct sockaddr_in6));
            ares_gethostbyaddr(channel, &addr6->sin6_addr,
                               sizeof(struct ares_in6_addr), AF_INET6,
                               nameinfo_callback, niquery);
          }
      }
    }
}

static void nameinfo_callback(void *arg, int status, int timeouts,
                              struct hostent *host)
{
  struct nameinfo_query *niquery = (struct nameinfo_query *) arg;
  char srvbuf[33];
  char *service = NULL;

  niquery->timeouts += timeouts;
  if (status == ARES_SUCCESS)
    {
      /* They want a service too */
      if (niquery->flags & ARES_NI_LOOKUPSERVICE)
        {
          if (niquery->family == AF_INET)
            service = lookup_service(niquery->addr.addr4.sin_port,
                                     niquery->flags, srvbuf, sizeof(srvbuf));
          else
            service = lookup_service(niquery->addr.addr6.sin6_port,
                                     niquery->flags, srvbuf, sizeof(srvbuf));
        }
      /* NOFQDN means we have to strip off the domain name portion.  We do
         this by determining our own domain name, then searching the string
         for this domain name and removing it.
       */
#ifdef HAVE_GETHOSTNAME
      if (niquery->flags & ARES_NI_NOFQDN)
        {
           char buf[255];
           char *domain;
           gethostname(buf, 255);
           if ((domain = strchr(buf, '.')) != NULL)
             {
               char *end = ares_striendstr(host->h_name, domain);
               if (end)
                 *end = 0;
             }
        }
#endif
      niquery->callback(niquery->arg, ARES_SUCCESS, niquery->timeouts,
                        (char *)(host->h_name),
                        service);
      free(niquery);
      return;
    }
  /* We couldn't find the host, but it's OK, we can use the IP */
  else if (status == ARES_ENOTFOUND && !(niquery->flags & ARES_NI_NAMEREQD))
    {
      char ipbuf[IPBUFSIZ];
      if (niquery->family == AF_INET)
        ares_inet_ntop(AF_INET, &niquery->addr.addr4.sin_addr, ipbuf,
                       IPBUFSIZ);
      else
        {
          ares_inet_ntop(AF_INET6, &niquery->addr.addr6.sin6_addr, ipbuf,
                         IPBUFSIZ);
#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
          append_scopeid(&niquery->addr.addr6, niquery->flags, ipbuf,
                         sizeof(ipbuf));
#endif
        }
      /* They want a service too */
      if (niquery->flags & ARES_NI_LOOKUPSERVICE)
        {
          if (niquery->family == AF_INET)
            service = lookup_service(niquery->addr.addr4.sin_port,
                                     niquery->flags, srvbuf, sizeof(srvbuf));
          else
            service = lookup_service(niquery->addr.addr6.sin6_port,
                                     niquery->flags, srvbuf, sizeof(srvbuf));
        }
      niquery->callback(niquery->arg, ARES_SUCCESS, niquery->timeouts, ipbuf,
                        service);
      free(niquery);
      return;
    }
  niquery->callback(niquery->arg, status, niquery->timeouts, NULL, NULL);
  free(niquery);
}

static char *lookup_service(unsigned short port, int flags,
                            char *buf, size_t buflen)
{
  const char *proto;
  struct servent *sep;
#ifdef HAVE_GETSERVBYPORT_R
  struct servent se;
#endif
  char tmpbuf[4096];

  if (port)
    {
      if (flags & ARES_NI_NUMERICSERV)
        sep = NULL;
      else
        {
          if (flags & ARES_NI_UDP)
            proto = "udp";
          else if (flags & ARES_NI_SCTP)
            proto = "sctp";
          else if (flags & ARES_NI_DCCP)
            proto = "dccp";
          else
            proto = "tcp";
#ifdef HAVE_GETSERVBYPORT_R
          sep = &se;
          memset(tmpbuf, 0, sizeof(tmpbuf));
#if GETSERVBYPORT_R_ARGS == 6
          if (getservbyport_r(port, proto, &se, (void *)tmpbuf,
                              sizeof(tmpbuf), &sep) != 0)
            sep = NULL;
#elif GETSERVBYPORT_R_ARGS == 5
          sep = getservbyport_r(port, proto, &se, (void *)tmpbuf,
                                sizeof(tmpbuf));
#elif GETSERVBYPORT_R_ARGS == 4
          if (getservbyport_r(port, proto, &se, (void *)tmpbuf) != 0)
            sep = NULL;
#else
          /* Lets just hope the OS uses TLS! */
          sep = getservbyport(port, proto);
#endif
#else
          /* Lets just hope the OS uses TLS! */
#if (defined(NETWARE) && !defined(__NOVELL_LIBC__))
          sep = getservbyport(port, (char*)proto);
#else
          sep = getservbyport(port, proto);
#endif
#endif
        }
      if (sep && sep->s_name)
        /* get service name */
        strcpy(tmpbuf, sep->s_name);
      else
        /* get port as a string */
        sprintf(tmpbuf, "%u", (unsigned int)ntohs(port));
      if (strlen(tmpbuf) < buflen)
        /* return it if buffer big enough */
        strcpy(buf, tmpbuf);
      else
        /* avoid reusing previous one */
        buf[0] = '\0';
      return buf;
    }
  buf[0] = '\0';
  return NULL;
}

#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
static void append_scopeid(struct sockaddr_in6 *addr6, unsigned int flags,
                           char *buf, size_t buflen)
{
#ifdef HAVE_IF_INDEXTONAME
  int is_ll, is_mcll;
#endif
  static const char fmt_u[] = "%u";
  static const char fmt_lu[] = "%lu";
  char tmpbuf[IF_NAMESIZE + 2];
  size_t bufl;
  const char *fmt = (sizeof(addr6->sin6_scope_id) > sizeof(unsigned int))?
    fmt_lu:fmt_u;

  tmpbuf[0] = '%';

#ifdef HAVE_IF_INDEXTONAME
  is_ll = IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr);
  is_mcll = IN6_IS_ADDR_MC_LINKLOCAL(&addr6->sin6_addr);
  if ((flags & ARES_NI_NUMERICSCOPE) ||
      (!is_ll && !is_mcll))
    {
       sprintf(&tmpbuf[1], fmt, addr6->sin6_scope_id);
    }
  else
    {
      if (if_indextoname(addr6->sin6_scope_id, &tmpbuf[1]) == NULL)
        sprintf(&tmpbuf[1], fmt, addr6->sin6_scope_id);
    }
#else
  sprintf(&tmpbuf[1], fmt, addr6->sin6_scope_id);
  (void) flags;
#endif
  tmpbuf[IF_NAMESIZE + 1] = '\0';
  bufl = strlen(buf);

  if(bufl + strlen(tmpbuf) < buflen)
    /* only append the scopeid string if it fits in the target buffer */
    strcpy(&buf[bufl], tmpbuf);
}
#endif

/* Determines if s1 ends with the string in s2 (case-insensitive) */
static char *ares_striendstr(const char *s1, const char *s2)
{
  const char *c1, *c2, *c1_begin;
  int lo1, lo2;
  size_t s1_len = strlen(s1), s2_len = strlen(s2);

  /* If the substr is longer than the full str, it can't match */
  if (s2_len > s1_len)
    return NULL;

  /* Jump to the end of s1 minus the length of s2 */
  c1_begin = s1+s1_len-s2_len;
  c1 = (const char *)c1_begin;
  c2 = s2;
  while (c2 < s2+s2_len)
    {
      lo1 = TOLOWER(*c1);
      lo2 = TOLOWER(*c2);
      if (lo1 != lo2)
        return NULL;
      else
        {
          c1++;
          c2++;
        }
    }
  if (c2 == c1 && c2 == NULL)
    return (char *)c1_begin;
  return NULL;
}