415 lines
13 KiB
C
Executable file
415 lines
13 KiB
C
Executable file
/**
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* @file
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* API functions for name resolving
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*
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*/
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/*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* This file is part of the lwIP TCP/IP stack.
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*
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* Author: Simon Goldschmidt
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*
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*/
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#include "lwip/netdb.h"
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#if LWIP_DNS && LWIP_SOCKET
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#include "lwip/err.h"
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#include "lwip/mem.h"
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#include "lwip/memp.h"
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#include "lwip/ip_addr.h"
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#include "lwip/api.h"
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#include "lwip/dns.h"
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#include <string.h>
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#include <stdlib.h>
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#ifdef MEMLEAK_DEBUG
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static const char mem_debug_file[] ICACHE_RODATA_ATTR STORE_ATTR = __FILE__;
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#endif
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/** helper struct for gethostbyname_r to access the char* buffer */
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struct gethostbyname_r_helper {
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ip_addr_t *addr_list[2];
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ip_addr_t addr;
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char *aliases;
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};
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/** h_errno is exported in netdb.h for access by applications. */
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#if LWIP_DNS_API_DECLARE_H_ERRNO
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int h_errno;
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#endif /* LWIP_DNS_API_DECLARE_H_ERRNO */
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/** define "hostent" variables storage: 0 if we use a static (but unprotected)
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* set of variables for lwip_gethostbyname, 1 if we use a local storage */
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#ifndef LWIP_DNS_API_HOSTENT_STORAGE
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#define LWIP_DNS_API_HOSTENT_STORAGE 0
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#endif
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/** define "hostent" variables storage */
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#if LWIP_DNS_API_HOSTENT_STORAGE
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#define HOSTENT_STORAGE
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#else
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#define HOSTENT_STORAGE static
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#endif /* LWIP_DNS_API_STATIC_HOSTENT */
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/**
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* Returns an entry containing addresses of address family AF_INET
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* for the host with name name.
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* Due to dns_gethostbyname limitations, only one address is returned.
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*
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* @param name the hostname to resolve
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* @return an entry containing addresses of address family AF_INET
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* for the host with name name
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*/
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struct hostent*
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lwip_gethostbyname(const char *name)
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{
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err_t err;
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ip_addr_t addr;
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/* buffer variables for lwip_gethostbyname() */
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HOSTENT_STORAGE struct hostent s_hostent;
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HOSTENT_STORAGE char *s_aliases;
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HOSTENT_STORAGE ip_addr_t s_hostent_addr;
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HOSTENT_STORAGE ip_addr_t *s_phostent_addr[2];
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HOSTENT_STORAGE char s_hostname[DNS_MAX_NAME_LENGTH + 1];
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/* query host IP address */
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err = netconn_gethostbyname(name, &addr);
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if (err != ERR_OK) {
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LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
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h_errno = HOST_NOT_FOUND;
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return NULL;
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}
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/* fill hostent */
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s_hostent_addr = addr;
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s_phostent_addr[0] = &s_hostent_addr;
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s_phostent_addr[1] = NULL;
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strncpy(s_hostname, name, DNS_MAX_NAME_LENGTH);
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s_hostname[DNS_MAX_NAME_LENGTH] = 0;
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s_hostent.h_name = s_hostname;
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s_aliases = NULL;
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s_hostent.h_aliases = &s_aliases;
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s_hostent.h_addrtype = AF_INET;
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s_hostent.h_length = sizeof(ip_addr_t);
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s_hostent.h_addr_list = (char**)&s_phostent_addr;
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#if DNS_DEBUG
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/* dump hostent */
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LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name == %s\n", s_hostent.h_name));
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LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases == %p\n", (void*)s_hostent.h_aliases));
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/* h_aliases are always empty */
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LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addrtype == %d\n", s_hostent.h_addrtype));
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LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_length == %d\n", s_hostent.h_length));
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LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list == %p\n", (void*)s_hostent.h_addr_list));
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if (s_hostent.h_addr_list != NULL) {
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u8_t idx;
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for (idx=0; s_hostent.h_addr_list[idx]; idx++) {
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LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i] == %p\n", idx, s_hostent.h_addr_list[idx]));
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LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]-> == %s\n", idx, ipaddr_ntoa((ip_addr_t*)s_hostent.h_addr_list[idx])));
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}
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}
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#endif /* DNS_DEBUG */
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#if LWIP_DNS_API_HOSTENT_STORAGE
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/* this function should return the "per-thread" hostent after copy from s_hostent */
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return sys_thread_hostent(&s_hostent);
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#else
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return &s_hostent;
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#endif /* LWIP_DNS_API_HOSTENT_STORAGE */
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}
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/**
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* Thread-safe variant of lwip_gethostbyname: instead of using a static
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* buffer, this function takes buffer and errno pointers as arguments
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* and uses these for the result.
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*
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* @param name the hostname to resolve
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* @param ret pre-allocated struct where to store the result
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* @param buf pre-allocated buffer where to store additional data
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* @param buflen the size of buf
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* @param result pointer to a hostent pointer that is set to ret on success
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* and set to zero on error
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* @param h_errnop pointer to an int where to store errors (instead of modifying
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* the global h_errno)
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* @return 0 on success, non-zero on error, additional error information
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* is stored in *h_errnop instead of h_errno to be thread-safe
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*/
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int
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lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
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size_t buflen, struct hostent **result, int *h_errnop)
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{
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err_t err;
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struct gethostbyname_r_helper *h;
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char *hostname;
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size_t namelen;
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int lh_errno;
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if (h_errnop == NULL) {
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/* ensure h_errnop is never NULL */
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h_errnop = &lh_errno;
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}
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if (result == NULL) {
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/* not all arguments given */
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*h_errnop = EINVAL;
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return -1;
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}
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/* first thing to do: set *result to nothing */
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*result = NULL;
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if ((name == NULL) || (ret == NULL) || (buf == NULL)) {
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/* not all arguments given */
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*h_errnop = EINVAL;
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return -1;
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}
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namelen = strlen(name);
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if (buflen < (sizeof(struct gethostbyname_r_helper) + namelen + 1 + (MEM_ALIGNMENT - 1))) {
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/* buf can't hold the data needed + a copy of name */
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*h_errnop = ERANGE;
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return -1;
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}
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h = (struct gethostbyname_r_helper*)LWIP_MEM_ALIGN(buf);
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hostname = ((char*)h) + sizeof(struct gethostbyname_r_helper);
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/* query host IP address */
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err = netconn_gethostbyname(name, &h->addr);
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if (err != ERR_OK) {
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LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
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*h_errnop = HOST_NOT_FOUND;
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return -1;
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}
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/* copy the hostname into buf */
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MEMCPY(hostname, name, namelen);
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hostname[namelen] = 0;
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/* fill hostent */
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h->addr_list[0] = &h->addr;
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h->addr_list[1] = NULL;
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h->aliases = NULL;
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ret->h_name = hostname;
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ret->h_aliases = &h->aliases;
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ret->h_addrtype = AF_INET;
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ret->h_length = sizeof(ip_addr_t);
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ret->h_addr_list = (char**)&h->addr_list;
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/* set result != NULL */
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*result = ret;
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/* return success */
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return 0;
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}
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/**
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* Frees one or more addrinfo structures returned by getaddrinfo(), along with
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* any additional storage associated with those structures. If the ai_next field
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* of the structure is not null, the entire list of structures is freed.
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*
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* @param ai struct addrinfo to free
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*/
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void
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lwip_freeaddrinfo(struct addrinfo *ai)
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{
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struct addrinfo *next;
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while (ai != NULL) {
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next = ai->ai_next;
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memp_free(MEMP_NETDB, ai);
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ai = next;
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}
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}
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/**
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* Translates the name of a service location (for example, a host name) and/or
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* a service name and returns a set of socket addresses and associated
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* information to be used in creating a socket with which to address the
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* specified service.
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* Memory for the result is allocated internally and must be freed by calling
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* lwip_freeaddrinfo()!
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*
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* Due to a limitation in dns_gethostbyname, only the first address of a
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* host is returned.
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* Also, service names are not supported (only port numbers)!
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*
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* @param nodename descriptive name or address string of the host
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* (may be NULL -> local address)
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* @param servname port number as string of NULL
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* @param hints structure containing input values that set socktype and protocol
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* @param res pointer to a pointer where to store the result (set to NULL on failure)
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* @return 0 on success, non-zero on failure
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*
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* @todo: implement AI_V4MAPPED, AI_ADDRCONFIG
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*/
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int
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lwip_getaddrinfo(const char *nodename, const char *servname,
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const struct addrinfo *hints, struct addrinfo **res)
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{
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err_t err;
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ip_addr_t addr;
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struct addrinfo *ai;
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struct sockaddr_storage *sa = NULL;
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int port_nr = 0;
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size_t total_size;
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size_t namelen = 0;
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int ai_family;
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if (res == NULL) {
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return EAI_FAIL;
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}
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*res = NULL;
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if ((nodename == NULL) && (servname == NULL)) {
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return EAI_NONAME;
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}
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if (hints != NULL) {
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ai_family = hints->ai_family;
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if ((ai_family != AF_UNSPEC)
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#if LWIP_IPV4
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&& (ai_family != AF_INET)
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#endif /* LWIP_IPV4 */
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#if LWIP_IPV6
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&& (ai_family != AF_INET6)
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#endif /* LWIP_IPV6 */
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) {
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return EAI_FAMILY;
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}
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} else {
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ai_family = AF_UNSPEC;
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}
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if (servname != NULL) {
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/* service name specified: convert to port number
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* @todo?: currently, only ASCII integers (port numbers) are supported (AI_NUMERICSERV)! */
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port_nr = atoi(servname);
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if ((port_nr <= 0) || (port_nr > 0xffff)) {
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return EAI_SERVICE;
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}
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}
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if (nodename != NULL) {
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/* service location specified, try to resolve */
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if ((hints != NULL) && (hints->ai_flags & AI_NUMERICHOST)) {
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/* no DNS lookup, just parse for an address string */
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if (!ipaddr_aton(nodename, &addr)) {
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return EAI_NONAME;
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}
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#if LWIP_IPV4 && LWIP_IPV6
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if ((IP_IS_V6_VAL(addr) && ai_family == AF_INET) ||
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(!IP_IS_V6_VAL(addr) && ai_family == AF_INET6)) {
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return EAI_NONAME;
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}
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#endif /* LWIP_IPV4 && LWIP_IPV6 */
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} else {
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#if LWIP_IPV4 && LWIP_IPV6
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/* AF_UNSPEC: prefer IPv4 */
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u8_t type = NETCONN_DNS_IPV4_IPV6;
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if (ai_family == AF_INET) {
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type = NETCONN_DNS_IPV4;
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} else if (ai_family == AF_INET6) {
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type = NETCONN_DNS_IPV6;
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}
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#endif /* LWIP_IPV4 && LWIP_IPV6 */
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err = netconn_gethostbyname_addrtype(nodename, &addr, type);
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if (err != ERR_OK) {
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return EAI_FAIL;
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}
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}
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} else {
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/* service location specified, use loopback address */
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if ((hints != NULL) && (hints->ai_flags & AI_PASSIVE)) {
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ip_addr_set_any(ai_family == AF_INET6, &addr);
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} else {
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ip_addr_set_loopback(ai_family == AF_INET6, &addr);
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}
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}
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total_size = sizeof(struct addrinfo) + sizeof(struct sockaddr_storage);
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if (nodename != NULL) {
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namelen = strlen(nodename);
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if (namelen > DNS_MAX_NAME_LENGTH) {
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/* invalid name length */
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return EAI_FAIL;
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}
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LWIP_ASSERT("namelen is too long", total_size + namelen + 1 > total_size);
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total_size += namelen + 1;
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}
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/* If this fails, please report to lwip-devel! :-) */
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LWIP_ASSERT("total_size <= NETDB_ELEM_SIZE: please report this!",
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total_size <= NETDB_ELEM_SIZE);
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ai = (struct addrinfo *)memp_malloc(MEMP_NETDB);
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if (ai == NULL) {
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return EAI_MEMORY;
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}
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memset(ai, 0, total_size);
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sa = (struct sockaddr_storage *)(void*)((u8_t*)ai + sizeof(struct addrinfo));
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if (IP_IS_V6_VAL(addr)) {
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#if LWIP_IPV6
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struct sockaddr_in6 *sa6 = (struct sockaddr_in6*)sa;
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/* set up sockaddr */
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inet6_addr_from_ip6addr(&sa6->sin6_addr, ip_2_ip6(&addr));
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sa6->sin6_family = AF_INET6;
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sa6->sin6_len = sizeof(struct sockaddr_in6);
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sa6->sin6_port = htons((u16_t)port_nr);
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ai->ai_family = AF_INET6;
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#endif /* LWIP_IPV6 */
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} else {
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#if LWIP_IPV4
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struct sockaddr_in *sa4 = (struct sockaddr_in*)sa;
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/* set up sockaddr */
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inet_addr_from_ipaddr(&sa4->sin_addr, ip_2_ip4(&addr));
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sa4->sin_family = AF_INET;
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sa4->sin_len = sizeof(struct sockaddr_in);
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sa4->sin_port = htons((u16_t)port_nr);
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ai->ai_family = AF_INET;
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#endif /* LWIP_IPV4 */
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}
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/* set up addrinfo */
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if (hints != NULL) {
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/* copy socktype & protocol from hints if specified */
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ai->ai_socktype = hints->ai_socktype;
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ai->ai_protocol = hints->ai_protocol;
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}
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if (nodename != NULL) {
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/* copy nodename to canonname if specified */
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ai->ai_canonname = ((char*)ai + sizeof(struct addrinfo) + sizeof(struct sockaddr_storage));
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MEMCPY(ai->ai_canonname, nodename, namelen);
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ai->ai_canonname[namelen] = 0;
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}
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ai->ai_addrlen = sizeof(struct sockaddr_storage);
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ai->ai_addr = (struct sockaddr*)sa;
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*res = ai;
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return 0;
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}
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#endif /* LWIP_DNS && LWIP_SOCKET */
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