native_client_sdk/src/libraries/nacl_io/host_resolver.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef __STDC_LIMIT_MACROS
   6 #define __STDC_LIMIT_MACROS
   7 #endif
   8
   9 #include "nacl_io/host_resolver.h"
  10
  11 #include <assert.h>
  12 #include <stdint.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15
  16 #include "nacl_io/kernel_proxy.h"
  17 #include "nacl_io/log.h"
  18 #include "nacl_io/ossocket.h"
  19 #include "nacl_io/pepper_interface.h"
  20
  21 #ifdef PROVIDES_SOCKET_API
  22
  23 namespace {
  24
  25 void HintsToPPHints(const addrinfo* hints, PP_HostResolver_Hint* pp_hints) {
  26   memset(pp_hints, 0, sizeof(*pp_hints));
  27
  28   if (hints->ai_family == AF_INET)
  29     pp_hints->family = PP_NETADDRESS_FAMILY_IPV4;
  30   else if (hints->ai_family == AF_INET6)
  31     pp_hints->family = PP_NETADDRESS_FAMILY_IPV6;
  32
  33   if (hints->ai_flags & AI_CANONNAME)
  34     pp_hints->flags = PP_HOSTRESOLVER_FLAG_CANONNAME;
  35 }
  36
  37 void CreateAddrInfo(const addrinfo* hints,
  38                     struct sockaddr* addr,
  39                     const char* name,
  40                     addrinfo** list_start,
  41                     addrinfo** list_end) {
  42   addrinfo* ai = static_cast<addrinfo*>(malloc(sizeof(addrinfo)));
  43   memset(ai, 0, sizeof(*ai));
  44
  45   if (hints && hints->ai_socktype)
  46     ai->ai_socktype = hints->ai_socktype;
  47   else
  48     ai->ai_socktype = SOCK_STREAM;
  49
  50   if (hints && hints->ai_protocol)
  51     ai->ai_protocol = hints->ai_protocol;
  52
  53   if (name)
  54     ai->ai_canonname = strdup(name);
  55
  56   switch (addr->sa_family) {
  57     case AF_INET6: {
  58       sockaddr_in6* in =
  59           static_cast<sockaddr_in6*>(malloc(sizeof(sockaddr_in6)));
  60       *in = *(sockaddr_in6*)addr;
  61       ai->ai_family = AF_INET6;
  62       ai->ai_addr = reinterpret_cast<sockaddr*>(in);
  63       ai->ai_addrlen = sizeof(*in);
  64       break;
  65     }
  66     case AF_INET: {
  67       sockaddr_in* in = static_cast<sockaddr_in*>(malloc(sizeof(sockaddr_in)));
  68       *in = *(sockaddr_in*)addr;
  69       ai->ai_family = AF_INET;
  70       ai->ai_addr = reinterpret_cast<sockaddr*>(in);
  71       ai->ai_addrlen = sizeof(*in);
  72       break;
  73     }
  74     default:
  75       assert(0);
  76       return;
  77   }
  78
  79   if (*list_start == NULL) {
  80     *list_start = ai;
  81     *list_end = ai;
  82     return;
  83   }
  84
  85   (*list_end)->ai_next = ai;
  86   *list_end = ai;
  87 }
  88
  89 }  // namespace
  90
  91 namespace nacl_io {
  92
  93 HostResolver::HostResolver() : hostent_(), ppapi_(NULL) {
  94 }
  95
  96 HostResolver::~HostResolver() {
  97   hostent_cleanup();
  98 }
  99
 100 void HostResolver::Init(PepperInterface* ppapi) {
 101   ppapi_ = ppapi;
 102 }
 103
 104 struct hostent* HostResolver::gethostbyname(const char* name) {
 105   h_errno = NETDB_INTERNAL;
 106
 107   struct addrinfo* ai;
 108   struct addrinfo hints;
 109   memset(&hints, 0, sizeof(hints));
 110   hints.ai_flags = AI_CANONNAME;
 111   hints.ai_family = AF_INET;
 112   int err = getaddrinfo(name, NULL, &hints, &ai);
 113   if (err) {
 114     switch (err) {
 115       case EAI_SYSTEM:
 116         h_errno = NO_RECOVERY;
 117         break;
 118       case EAI_NONAME:
 119         h_errno = HOST_NOT_FOUND;
 120         break;
 121       default:
 122         h_errno = NETDB_INTERNAL;
 123         break;
 124     }
 125     return NULL;
 126   }
 127
 128   // We use a single hostent struct for all calls to to gethostbyname
 129   // (as explicitly permitted by the spec - gethostbyname is NOT supposed to
 130   // be threadsafe!).  However by using a lock around all the global data
 131   // manipulation we can at least ensure that the call doesn't crash.
 132   AUTO_LOCK(gethostbyname_lock_);
 133
 134   // The first thing we do is free any malloced data left over from
 135   // the last call.
 136   hostent_cleanup();
 137
 138   switch (ai->ai_family) {
 139     case AF_INET:
 140       hostent_.h_addrtype = AF_INET;
 141       hostent_.h_length = sizeof(in_addr);
 142       break;
 143     case AF_INET6:
 144       hostent_.h_addrtype = AF_INET6;
 145       hostent_.h_length = sizeof(in6_addr);
 146       break;
 147     default:
 148       return NULL;
 149   }
 150
 151   if (ai->ai_canonname != NULL)
 152     hostent_.h_name = strdup(ai->ai_canonname);
 153   else
 154     hostent_.h_name = strdup(name);
 155
 156   // Aliases aren't supported at the moment, so we just make an empty list.
 157   hostent_.h_aliases = static_cast<char**>(malloc(sizeof(char*)));
 158   if (NULL == hostent_.h_aliases)
 159     return NULL;
 160   hostent_.h_aliases[0] = NULL;
 161
 162   // Count number of address in list
 163   int num_addresses = 0;
 164   struct addrinfo* current = ai;
 165   while (current != NULL) {
 166     // Only count address that have the same type as first address
 167     if (current->ai_family == hostent_.h_addrtype)
 168       num_addresses++;
 169     current = current->ai_next;
 170   }
 171
 172   // Allocate address list
 173   hostent_.h_addr_list = static_cast<char**>(calloc(num_addresses + 1,
 174                                                     sizeof(char*)));
 175   if (NULL == hostent_.h_addr_list)
 176     return NULL;
 177
 178   // Copy all addresses of the relevant family.
 179   current = ai;
 180   char** hostent_addr = hostent_.h_addr_list;
 181   while (current != NULL) {
 182     if (current->ai_family != hostent_.h_addrtype) {
 183       current = current->ai_next;
 184       continue;
 185     }
 186     *hostent_addr = static_cast<char*>(malloc(hostent_.h_length));
 187     switch (current->ai_family) {
 188       case AF_INET: {
 189         sockaddr_in* in = reinterpret_cast<sockaddr_in*>(current->ai_addr);
 190         memcpy(*hostent_addr, &in->sin_addr.s_addr, hostent_.h_length);
 191         break;
 192       }
 193       case AF_INET6: {
 194         sockaddr_in6* in6 = reinterpret_cast<sockaddr_in6*>(current->ai_addr);
 195         memcpy(*hostent_addr, &in6->sin6_addr.s6_addr, hostent_.h_length);
 196         break;
 197       }
 198     }
 199     current = current->ai_next;
 200     hostent_addr++;
 201   }
 202
 203   freeaddrinfo(ai);
 204
 205 #if !defined(h_addr)
 206   // Copy element zero of h_addr_list to h_addr when h_addr is not defined
 207   // as in some libc's h_addr may be a separate member instead of a macro.
 208   hostent_.h_addr = hostent_.h_addr_list[0];
 209 #endif
 210
 211   return &hostent_;
 212 }
 213
 214 void HostResolver::freeaddrinfo(struct addrinfo* res) {
 215   while (res) {
 216     struct addrinfo* cur = res;
 217     res = res->ai_next;
 218     free(cur->ai_addr);
 219     free(cur->ai_canonname);
 220     free(cur);
 221   }
 222 }
 223
 224 int HostResolver::getaddrinfo(const char* node,
 225                               const char* service,
 226                               const struct addrinfo* hints_in,
 227                               struct addrinfo** result) {
 228   *result = NULL;
 229   struct addrinfo* end = NULL;
 230
 231   if (node == NULL && service == NULL) {
 232     LOG_TRACE("node and service are NULL.");
 233     return EAI_NONAME;
 234   }
 235
 236   // Check the service name (port).  Currently we only handle numeric
 237   // services.
 238   long port = 0;
 239   if (service != NULL) {
 240     char* cp;
 241     port = strtol(service, &cp, 10);
 242     if (port >= 0 && port <= UINT16_MAX && *cp == '\0') {
 243       port = htons(port);
 244     } else {
 245       LOG_TRACE("Service \"%s\" not supported.", service);
 246       return EAI_SERVICE;
 247     }
 248   }
 249
 250   struct addrinfo default_hints;
 251   memset(&default_hints, 0, sizeof(default_hints));
 252   const struct addrinfo* hints = hints_in ? hints_in : &default_hints;
 253
 254   // Verify values passed in hints structure
 255   switch (hints->ai_family) {
 256     case AF_INET6:
 257     case AF_INET:
 258     case AF_UNSPEC:
 259       break;
 260     default:
 261       LOG_TRACE("Unknown family: %d.", hints->ai_family);
 262       return EAI_FAMILY;
 263   }
 264
 265   struct sockaddr_in addr_in;
 266   memset(&addr_in, 0, sizeof(addr_in));
 267   addr_in.sin_family = AF_INET;
 268   addr_in.sin_port = port;
 269
 270   struct sockaddr_in6 addr_in6;
 271   memset(&addr_in6, 0, sizeof(addr_in6));
 272   addr_in6.sin6_family = AF_INET6;
 273   addr_in6.sin6_port = port;
 274
 275   if (node) {
 276     // Handle numeric node name.
 277     if (hints->ai_family == AF_INET || hints->ai_family == AF_UNSPEC) {
 278       in_addr in;
 279       if (inet_pton(AF_INET, node, &in)) {
 280         addr_in.sin_addr = in;
 281         CreateAddrInfo(hints, (sockaddr*)&addr_in, node, result, &end);
 282         return 0;
 283       }
 284     }
 285
 286     if (hints->ai_family == AF_INET6 || hints->ai_family == AF_UNSPEC) {
 287       in6_addr in6;
 288       if (inet_pton(AF_INET6, node, &in6)) {
 289         addr_in6.sin6_addr = in6;
 290         CreateAddrInfo(hints, (sockaddr*)&addr_in6, node, result, &end);
 291         return 0;
 292       }
 293     }
 294   }
 295
 296   // Handle AI_PASSIVE (used for listening sockets, e.g. INADDR_ANY)
 297   if (node == NULL && (hints->ai_flags & AI_PASSIVE)) {
 298     if (hints->ai_family == AF_INET6 || hints->ai_family == AF_UNSPEC) {
 299       const in6_addr in6addr_any = IN6ADDR_ANY_INIT;
 300       memcpy(&addr_in6.sin6_addr.s6_addr, &in6addr_any, sizeof(in6addr_any));
 301       CreateAddrInfo(hints, (sockaddr*)&addr_in6, NULL, result, &end);
 302     }
 303
 304     if (hints->ai_family == AF_INET || hints->ai_family == AF_UNSPEC) {
 305       addr_in.sin_addr.s_addr = INADDR_ANY;
 306       CreateAddrInfo(hints, (sockaddr*)&addr_in, NULL, result, &end);
 307     }
 308     return 0;
 309   }
 310
 311   if (NULL == ppapi_) {
 312     LOG_ERROR("ppapi_ is NULL.");
 313     return EAI_SYSTEM;
 314   }
 315
 316   // Use PPAPI interface to resolve nodename
 317   HostResolverInterface* resolver_iface = ppapi_->GetHostResolverInterface();
 318   VarInterface* var_iface = ppapi_->GetVarInterface();
 319   NetAddressInterface* netaddr_iface = ppapi_->GetNetAddressInterface();
 320
 321   if (!(resolver_iface && var_iface && netaddr_iface)) {
 322     LOG_ERROR("Got NULL interface(s): %s%s%s",
 323               resolver_iface ? "" : "HostResolver ",
 324               var_iface ? "" : "Var ",
 325               netaddr_iface ? "" : "NetAddress");
 326     return EAI_SYSTEM;
 327   }
 328
 329   ScopedResource scoped_resolver(ppapi_,
 330                                  resolver_iface->Create(ppapi_->GetInstance()));
 331   PP_Resource resolver = scoped_resolver.pp_resource();
 332
 333   struct PP_HostResolver_Hint pp_hints;
 334   HintsToPPHints(hints, &pp_hints);
 335
 336   int err = resolver_iface->Resolve(resolver,
 337                                     node,
 338                                     0,
 339                                     &pp_hints,
 340                                     PP_BlockUntilComplete());
 341   if (err) {
 342     switch (err) {
 343       case PP_ERROR_NOACCESS:
 344         return EAI_SYSTEM;
 345       case PP_ERROR_NAME_NOT_RESOLVED:
 346         return EAI_NONAME;
 347       default:
 348         return EAI_SYSTEM;
 349     }
 350   }
 351
 352   char* canon_name = NULL;
 353   if (hints->ai_flags & AI_CANONNAME) {
 354     PP_Var name_var = resolver_iface->GetCanonicalName(resolver);
 355     if (PP_VARTYPE_STRING == name_var.type) {
 356       uint32_t len = 0;
 357       const char* tmp = var_iface->VarToUtf8(name_var, &len);
 358       // For some reason GetCanonicalName alway returns an empty
 359       // string so this condition is never true.
 360       // TODO(sbc): investigate this issue with PPAPI team.
 361       if (len > 0) {
 362         // Copy and NULL-terminate the UTF8 string var.
 363         canon_name = static_cast<char*>(malloc(len + 1));
 364         strncpy(canon_name, tmp, len);
 365         canon_name[len] = '\0';
 366       }
 367     }
 368     if (!canon_name)
 369       canon_name = strdup(node);
 370     var_iface->Release(name_var);
 371   }
 372
 373   int num_addresses = resolver_iface->GetNetAddressCount(resolver);
 374   if (0 == num_addresses)
 375     return EAI_NODATA;
 376
 377   // Convert address to sockaddr struct.
 378   for (int i = 0; i < num_addresses; i++) {
 379     ScopedResource addr(ppapi_, resolver_iface->GetNetAddress(resolver, i));
 380     PP_Resource resource = addr.pp_resource();
 381     assert(resource != 0);
 382     assert(PP_ToBool(netaddr_iface->IsNetAddress(resource)));
 383     struct sockaddr* sockaddr = NULL;
 384     switch (netaddr_iface->GetFamily(resource)) {
 385       case PP_NETADDRESS_FAMILY_IPV4: {
 386         struct PP_NetAddress_IPv4 pp_addr;
 387         if (!netaddr_iface->DescribeAsIPv4Address(resource, &pp_addr)) {
 388           assert(false);
 389           break;
 390         }
 391         memcpy(&addr_in.sin_addr.s_addr, pp_addr.addr, sizeof(in_addr_t));
 392         sockaddr = (struct sockaddr*)&addr_in;
 393         break;
 394       }
 395       case PP_NETADDRESS_FAMILY_IPV6: {
 396         struct PP_NetAddress_IPv6 pp_addr;
 397         if (!netaddr_iface->DescribeAsIPv6Address(resource, &pp_addr)) {
 398           assert(false);
 399           break;
 400         }
 401         memcpy(&addr_in6.sin6_addr.s6_addr, pp_addr.addr, sizeof(in6_addr));
 402         sockaddr = (struct sockaddr*)&addr_in6;
 403         break;
 404       }
 405       default:
 406         return EAI_SYSTEM;
 407     }
 408
 409     if (sockaddr != NULL)
 410       CreateAddrInfo(hints, sockaddr, canon_name, result, &end);
 411
 412     if (canon_name) {
 413       free(canon_name);
 414       canon_name = NULL;
 415     }
 416   }
 417
 418   return 0;
 419 }
 420
 421 // Frees all of the deep pointers in a hostent struct. Called between uses of
 422 // gethostbyname, and when the kernel_proxy object is destroyed.
 423 void HostResolver::hostent_cleanup() {
 424   if (NULL != hostent_.h_name) {
 425     free(hostent_.h_name);
 426   }
 427   if (NULL != hostent_.h_aliases) {
 428     for (int i = 0; NULL != hostent_.h_aliases[i]; i++) {
 429       free(hostent_.h_aliases[i]);
 430     }
 431     free(hostent_.h_aliases);
 432   }
 433   if (NULL != hostent_.h_addr_list) {
 434     for (int i = 0; NULL != hostent_.h_addr_list[i]; i++) {
 435       free(hostent_.h_addr_list[i]);
 436     }
 437     free(hostent_.h_addr_list);
 438   }
 439   hostent_.h_name = NULL;
 440   hostent_.h_aliases = NULL;
 441   hostent_.h_addr_list = NULL;
 442 #if !defined(h_addr)
 443   // Initialize h_addr separately in the case where it is not a macro.
 444   hostent_.h_addr = NULL;
 445 #endif
 446 }
 447
 448 }  // namespace nacl_io
 449
 450 #endif  // PROVIDES_SOCKET_API