src/net/resolver.c

   1 /* libmpdclient
   2    (c) 2003-2017 The Music Player Daemon Project
   3    This project's homepage is: http://www.musicpd.org
   4
   5    Redistribution and use in source and binary forms, with or without
   6    modification, are permitted provided that the following conditions
   7    are met:
   8
   9    - Redistributions of source code must retain the above copyright
  10    notice, this list of conditions and the following disclaimer.
  11
  12    - Redistributions in binary form must reproduce the above copyright
  13    notice, this list of conditions and the following disclaimer in the
  14    documentation and/or other materials provided with the distribution.
  15
  16    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19    A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
  20    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  21    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  22    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  23    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  24    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  25    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  26    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27 */
  28
  29 #include "resolver.h"
  30 #include "config.h"
  31
  32 #include <stdbool.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #ifdef WIN32
  38 #  include <winsock2.h>
  39 #  include <ws2tcpip.h>
  40 #else
  41 #  include <sys/socket.h>
  42 #  include <sys/un.h>
  43 #ifdef ENABLE_TCP
  44 #  include <netinet/in.h>
  45 #  include <arpa/inet.h>
  46 #  include <netdb.h>
  47 #endif
  48 #endif
  49
  50 struct resolver {
  51         enum {
  52                 TYPE_ZERO, TYPE_ONE, TYPE_ANY
  53         } type;
  54
  55 #ifdef ENABLE_TCP
  56 #ifdef HAVE_GETADDRINFO
  57         struct addrinfo *ai;
  58         const struct addrinfo *next;
  59 #else
  60         struct sockaddr_in sin;
  61 #endif
  62 #endif
  63
  64         struct resolver_address current;
  65
  66 #ifndef WIN32
  67         struct sockaddr_un saun;
  68 #endif
  69 };
  70
  71 struct resolver *
  72 resolver_new(const char *host, unsigned port)
  73 {
  74         struct resolver *resolver;
  75
  76         resolver = malloc(sizeof(*resolver));
  77         if (resolver == NULL)
  78                 return NULL;
  79
  80         if (host[0] == '/' || host[0] == '@') {
  81 #ifndef WIN32
  82                 const bool is_abstract = *host == '@';
  83                 /* sun_path must be null-terminated unless it's an abstract
  84                    socket */
  85                 const size_t path_length = strlen(host) + !is_abstract;
  86                 if (path_length > sizeof(resolver->saun.sun_path)) {
  87                         free(resolver);
  88                         return NULL;
  89                 }
  90
  91                 resolver->saun.sun_family = AF_UNIX;
  92                 memcpy(resolver->saun.sun_path, host, path_length);
  93
  94                 if (host[0] == '@')
  95                         /* abstract socket */
  96                         resolver->saun.sun_path[0] = 0;
  97
  98                 resolver->current.family = PF_UNIX;
  99                 resolver->current.protocol = 0;
 100                 resolver->current.addrlen = sizeof(resolver->saun)
 101                         - sizeof(resolver->saun.sun_path) + path_length;
 102                 resolver->current.addr = (const struct sockaddr *)&resolver->saun;
 103                 resolver->type = TYPE_ONE;
 104 #else /* WIN32 */
 105                 /* there are no UNIX domain sockets on Windows */
 106                 free(resolver);
 107                 return NULL;
 108 #endif /* WIN32 */
 109         } else {
 110 #ifdef ENABLE_TCP
 111 #ifdef HAVE_GETADDRINFO
 112                 struct addrinfo hints;
 113                 char service[20];
 114                 int ret;
 115
 116                 memset(&hints, 0, sizeof(hints));
 117                 hints.ai_family = PF_UNSPEC;
 118                 hints.ai_socktype = SOCK_STREAM;
 119                 hints.ai_protocol = IPPROTO_TCP;
 120
 121                 snprintf(service, sizeof(service), "%d", port);
 122
 123                 ret = getaddrinfo(host, service, &hints, &resolver->ai);
 124                 if (ret != 0) {
 125                         free(resolver);
 126                         return NULL;
 127                 }
 128
 129                 resolver->next = resolver->ai;
 130                 resolver->type = TYPE_ANY;
 131 #else
 132                 const struct hostent *he;
 133
 134                 he = gethostbyname(host);
 135                 if (he == NULL) {
 136                         free(resolver);
 137                         return NULL;
 138                 }
 139
 140                 if (he->h_addrtype != AF_INET) {
 141                         free(resolver);
 142                         return NULL;
 143                 }
 144
 145
 146                 memset(&resolver->sin, 0, sizeof(resolver->sin));
 147                 resolver->sin.sin_family = AF_INET;
 148                 resolver->sin.sin_port = htons(port);
 149                 memcpy((char *)&resolver->sin.sin_addr.s_addr,
 150                        (char *)he->h_addr, he->h_length);
 151
 152                 resolver->current.family = PF_INET;
 153                 resolver->current.protocol = 0;
 154                 resolver->current.addrlen = sizeof(resolver->sin);
 155                 resolver->current.addr = (const struct sockaddr *)&resolver->sin;
 156
 157                 resolver->type = TYPE_ONE;
 158 #endif
 159 #else /* !ENABLE_TCP */
 160                 (void)port;
 161                 free(resolver);
 162                 return NULL;
 163 #endif
 164         }
 165
 166         return resolver;
 167 }
 168
 169 void
 170 resolver_free(struct resolver *resolver)
 171 {
 172 #if defined(ENABLE_TCP) && defined(HAVE_GETADDRINFO)
 173         if (resolver->type == TYPE_ANY)
 174                 freeaddrinfo(resolver->ai);
 175 #endif
 176         free(resolver);
 177 }
 178
 179 const struct resolver_address *
 180 resolver_next(struct resolver *resolver)
 181 {
 182         if (resolver->type == TYPE_ZERO)
 183                 return NULL;
 184
 185         if (resolver->type == TYPE_ONE) {
 186                 resolver->type = TYPE_ZERO;
 187                 return &resolver->current;
 188         }
 189
 190 #if defined(ENABLE_TCP) && defined(HAVE_GETADDRINFO)
 191         if (resolver->next == NULL)
 192                 return NULL;
 193
 194         resolver->current.family = resolver->next->ai_family;
 195         resolver->current.protocol = resolver->next->ai_protocol;
 196         resolver->current.addrlen = resolver->next->ai_addrlen;
 197         resolver->current.addr = resolver->next->ai_addr;
 198
 199         resolver->next = resolver->next->ai_next;
 200
 201         return &resolver->current;
 202 #else
 203         return NULL;
 204 #endif
 205 }