FreeRTOS/Common/ethernet/lwIP_130/src/api/netdb.c

   1 /**
   2  * @file
   3  * API functions for name resolving
   4  *
   5  */
   6
   7 /*
   8  * Redistribution and use in source and binary forms, with or without modification,
   9  * are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright notice,
  12  *    this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright notice,
  14  *    this list of conditions and the following disclaimer in the documentation
  15  *    and/or other materials provided with the distribution.
  16  * 3. The name of the author may not be used to endorse or promote products
  17  *    derived from this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  20  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  22  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  23  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  24  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  27  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  28  * OF SUCH DAMAGE.
  29  *
  30  * This file is part of the lwIP TCP/IP stack.
  31  *
  32  * Author: Simon Goldschmidt
  33  *
  34  */
  35
  36 #include "lwip/netdb.h"
  37
  38 #if LWIP_DNS && LWIP_SOCKET
  39
  40 #include "lwip/err.h"
  41 #include "lwip/mem.h"
  42 #include "lwip/ip_addr.h"
  43 #include "lwip/api.h"
  44
  45 /** helper struct for gethostbyname_r to access the char* buffer */
  46 struct gethostbyname_r_helper {
  47   struct ip_addr *addrs;
  48   struct ip_addr addr;
  49   char *aliases;
  50 };
  51
  52 /** h_errno is exported in netdb.h for access by applications. */
  53 #if LWIP_DNS_API_DECLARE_H_ERRNO
  54 int h_errno;
  55 #endif /* LWIP_DNS_API_DECLARE_H_ERRNO */
  56
  57 /** define "hostent" variables storage: 0 if we use a static (but unprotected)
  58  * set of variables for lwip_gethostbyname, 1 if we use a local storage */
  59 #ifndef LWIP_DNS_API_HOSTENT_STORAGE
  60 #define LWIP_DNS_API_HOSTENT_STORAGE 0
  61 #endif
  62
  63 /** define "hostent" variables storage */
  64 #if LWIP_DNS_API_HOSTENT_STORAGE
  65 #define HOSTENT_STORAGE
  66 #else
  67 #define HOSTENT_STORAGE static
  68 #endif /* LWIP_DNS_API_STATIC_HOSTENT */
  69
  70 /**
  71  * Returns an entry containing addresses of address family AF_INET
  72  * for the host with name name.
  73  * Due to dns_gethostbyname limitations, only one address is returned.
  74  *
  75  * @param name the hostname to resolve
  76  * @return an entry containing addresses of address family AF_INET
  77  *         for the host with name name
  78  */
  79 struct hostent*
  80 lwip_gethostbyname(const char *name)
  81 {
  82   err_t err;
  83   struct ip_addr addr;
  84
  85   /* buffer variables for lwip_gethostbyname() */
  86   HOSTENT_STORAGE struct hostent s_hostent;
  87   HOSTENT_STORAGE char *s_aliases;
  88   HOSTENT_STORAGE struct ip_addr s_hostent_addr;
  89   HOSTENT_STORAGE struct ip_addr *s_phostent_addr;
  90
  91   /* query host IP address */
  92   err = netconn_gethostbyname(name, &addr);
  93   if (err != ERR_OK) {
  94     LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
  95     h_errno = HOST_NOT_FOUND;
  96     return NULL;
  97   }
  98
  99   /* fill hostent */
 100   s_hostent_addr = addr;
 101   s_phostent_addr = &s_hostent_addr;
 102   s_hostent.h_name = (char*)name;
 103   s_hostent.h_aliases = &s_aliases;
 104   s_hostent.h_addrtype = AF_INET;
 105   s_hostent.h_length = sizeof(struct ip_addr);
 106   s_hostent.h_addr_list = (char**)&s_phostent_addr;
 107
 108 #if DNS_DEBUG
 109   /* dump hostent */
 110   LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name           == %s\n",      s_hostent.h_name));
 111   LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases        == 0x%08lX\n",(u32_t)(s_hostent.h_aliases)));
 112   if (s_hostent.h_aliases != NULL) {
 113     u8_t idx;
 114     for ( idx=0; s_hostent.h_aliases[idx]; idx++) {
 115       LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]->   == 0x%08lX\n", idx, s_hostent.h_aliases[idx]));
 116       LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]->   == %s\n",      idx, s_hostent.h_aliases[idx]));
 117     }
 118   }
 119   LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addrtype       == %lu\n",    (u32_t)(s_hostent.h_addrtype)));
 120   LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_length         == %lu\n",    (u32_t)(s_hostent.h_length)));
 121   LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list      == 0x%08lX\n", s_hostent.h_addr_list));
 122   if (s_hostent.h_addr_list != NULL) {
 123     u8_t idx;
 124     for ( idx=0; s_hostent.h_addr_list[idx]; idx++) {
 125       LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]   == 0x%08lX\n", idx, s_hostent.h_addr_list[idx]));
 126       LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]-> == %s\n",      idx, inet_ntoa(*((struct in_addr*)(s_hostent.h_addr_list[idx])))));
 127     }
 128   }
 129 #endif /* DNS_DEBUG */
 130
 131 #if LWIP_DNS_API_HOSTENT_STORAGE
 132   /* this function should return the "per-thread" hostent after copy from s_hostent */
 133   return sys_thread_hostent(&s_hostent);
 134 #else
 135   return &s_hostent;
 136 #endif /* LWIP_DNS_API_HOSTENT_STORAGE */
 137 }
 138
 139 /**
 140  * Thread-safe variant of lwip_gethostbyname: instead of using a static
 141  * buffer, this function takes buffer and errno pointers as arguments
 142  * and uses these for the result.
 143  *
 144  * @param name the hostname to resolve
 145  * @param ret pre-allocated struct where to store the result
 146  * @param buf pre-allocated buffer where to store additional data
 147  * @param buflen the size of buf
 148  * @param result pointer to a hostent pointer that is set to ret on success
 149  *               and set to zero on error
 150  * @param h_errnop pointer to an int where to store errors (instead of modifying
 151  *                 the global h_errno)
 152  * @return 0 on success, non-zero on error, additional error information
 153  *         is stored in *h_errnop instead of h_errno to be thread-safe
 154  */
 155 int
 156 lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
 157                 size_t buflen, struct hostent **result, int *h_errnop)
 158 {
 159   err_t err;
 160   struct gethostbyname_r_helper *h;
 161   char *hostname;
 162   size_t namelen;
 163   int lh_errno;
 164
 165   if (h_errnop == NULL) {
 166     /* ensure h_errnop is never NULL */
 167     h_errnop = &lh_errno;
 168   }
 169
 170   if (result == NULL) {
 171     /* not all arguments given */
 172     *h_errnop = EINVAL;
 173     return -1;
 174   }
 175   /* first thing to do: set *result to nothing */
 176   *result = NULL;
 177   if ((name == NULL) || (ret == NULL) || (buf == 0)) {
 178     /* not all arguments given */
 179     *h_errnop = EINVAL;
 180     return -1;
 181   }
 182
 183   namelen = strlen(name);
 184   if (buflen < (sizeof(struct gethostbyname_r_helper) + namelen + 1 + (MEM_ALIGNMENT - 1))) {
 185     /* buf can't hold the data needed + a copy of name */
 186     *h_errnop = ERANGE;
 187     return -1;
 188   }
 189
 190   h = (struct gethostbyname_r_helper*)LWIP_MEM_ALIGN(buf);
 191   hostname = ((char*)h) + sizeof(struct gethostbyname_r_helper);
 192
 193   /* query host IP address */
 194   err = netconn_gethostbyname(name, &(h->addr));
 195   if (err != ERR_OK) {
 196     LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
 197     *h_errnop = ENSRNOTFOUND;
 198     return -1;
 199   }
 200
 201   /* copy the hostname into buf */
 202   MEMCPY(hostname, name, namelen);
 203   hostname[namelen] = 0;
 204
 205   /* fill hostent */
 206   h->addrs = &(h->addr);
 207   h->aliases = NULL;
 208   ret->h_name = (char*)hostname;
 209   ret->h_aliases = &(h->aliases);
 210   ret->h_addrtype = AF_INET;
 211   ret->h_length = sizeof(struct ip_addr);
 212   ret->h_addr_list = (char**)&(h->addrs);
 213
 214   /* set result != NULL */
 215   *result = ret;
 216
 217   /* return success */
 218   return 0;
 219 }
 220
 221 /**
 222  * Frees one or more addrinfo structures returned by getaddrinfo(), along with
 223  * any additional storage associated with those structures. If the ai_next field
 224  * of the structure is not null, the entire list of structures is freed.
 225  *
 226  * @param ai struct addrinfo to free
 227  */
 228 void
 229 lwip_freeaddrinfo(struct addrinfo *ai)
 230 {
 231   struct addrinfo *next;
 232
 233   while (ai != NULL) {
 234     if (ai->ai_addr != NULL) {
 235       mem_free(ai->ai_addr);
 236     }
 237     if (ai->ai_canonname != NULL) {
 238       mem_free(ai->ai_canonname);
 239     }
 240     next = ai->ai_next;
 241     mem_free(ai);
 242     ai = next;
 243   }
 244 }
 245
 246 /**
 247  * Translates the name of a service location (for example, a host name) and/or
 248  * a service name and returns a set of socket addresses and associated
 249  * information to be used in creating a socket with which to address the
 250  * specified service.
 251  * Memory for the result is allocated internally and must be freed by calling
 252  * lwip_freeaddrinfo()!
 253  *
 254  * Due to a limitation in dns_gethostbyname, only the first address of a
 255  * host is returned.
 256  * Also, service names are not supported (only port numbers)!
 257  *
 258  * @param nodename descriptive name or address string of the host
 259  *                 (may be NULL -> local address)
 260  * @param servname port number as string of NULL
 261  * @param hints structure containing input values that set socktype and protocol
 262  * @param res pointer to a pointer where to store the result (set to NULL on failure)
 263  * @return 0 on success, non-zero on failure
 264  */
 265 int
 266 lwip_getaddrinfo(const char *nodename, const char *servname,
 267        const struct addrinfo *hints, struct addrinfo **res)
 268 {
 269   err_t err;
 270   struct ip_addr addr;
 271   struct addrinfo *ai;
 272   struct sockaddr_in *sa = NULL;
 273   int port_nr = 0;
 274
 275   if (res == NULL) {
 276     return EAI_FAIL;
 277   }
 278   *res = NULL;
 279   if ((nodename == NULL) && (servname == NULL)) {
 280     return EAI_NONAME;
 281   }
 282
 283   if (servname != NULL) {
 284     /* service name specified: convert to port number
 285      * @todo?: currently, only ASCII integers (port numbers) are supported! */
 286     port_nr = atoi(servname);
 287     if ((port_nr <= 0) || (port_nr > 0xffff)) {
 288       return EAI_SERVICE;
 289     }
 290   }
 291
 292   if (nodename != NULL) {
 293     /* service location specified, try to resolve */
 294     err = netconn_gethostbyname(nodename, &addr);
 295     if (err != ERR_OK) {
 296       return EAI_FAIL;
 297     }
 298   } else {
 299     /* service location specified, use loopback address */
 300     addr.addr = INADDR_LOOPBACK;
 301   }
 302
 303   ai = mem_malloc(sizeof(struct addrinfo));
 304   if (ai == NULL) {
 305     goto memerr;
 306   }
 307   memset(ai, 0, sizeof(struct addrinfo));
 308   sa = mem_malloc(sizeof(struct sockaddr_in));
 309   if (sa == NULL) {
 310     goto memerr;
 311   }
 312   memset(sa, 0, sizeof(struct sockaddr_in));
 313   /* set up sockaddr */
 314   sa->sin_addr.s_addr = addr.addr;
 315   sa->sin_family = AF_INET;
 316   sa->sin_len = sizeof(struct sockaddr_in);
 317   sa->sin_port = htons(port_nr);
 318
 319   /* set up addrinfo */
 320   ai->ai_family = AF_INET;
 321   if (hints != NULL) {
 322     /* copy socktype & protocol from hints if specified */
 323     ai->ai_socktype = hints->ai_socktype;
 324     ai->ai_protocol = hints->ai_protocol;
 325   }
 326   if (nodename != NULL) {
 327     /* copy nodename to canonname if specified */
 328     size_t namelen = strlen(nodename);
 329     ai->ai_canonname = mem_malloc(namelen + 1);
 330     if (ai->ai_canonname == NULL) {
 331       goto memerr;
 332     }
 333     MEMCPY(ai->ai_canonname, nodename, namelen);
 334     ai->ai_canonname[namelen] = 0;
 335   }
 336   ai->ai_addrlen = sizeof(struct sockaddr_in);
 337   ai->ai_addr = (struct sockaddr*)sa;
 338
 339   *res = ai;
 340
 341   return 0;
 342 memerr:
 343   if (ai != NULL) {
 344     mem_free(ai);
 345   }
 346   if (sa != NULL) {
 347     mem_free(sa);
 348   }
 349   return EAI_MEMORY;
 350 }
 351
 352 #endif /* LWIP_DNS && LWIP_SOCKET */