www.pudn.com > lwip-1.3.0.rar > netdb.c
/**
* @file
* API functions for name resolving
*
*/
/*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Simon Goldschmidt
*
*/
#include "lwip/netdb.h"
#if LWIP_DNS && LWIP_SOCKET
#include "lwip/err.h"
#include "lwip/mem.h"
#include "lwip/ip_addr.h"
#include "lwip/api.h"
/** helper struct for gethostbyname_r to access the char* buffer */
struct gethostbyname_r_helper {
struct ip_addr *addrs;
struct ip_addr addr;
char *aliases;
};
/** h_errno is exported in netdb.h for access by applications. */
#if LWIP_DNS_API_DECLARE_H_ERRNO
int h_errno;
#endif /* LWIP_DNS_API_DECLARE_H_ERRNO */
/** define "hostent" variables storage: 0 if we use a static (but unprotected)
* set of variables for lwip_gethostbyname, 1 if we use a local storage */
#ifndef LWIP_DNS_API_HOSTENT_STORAGE
#define LWIP_DNS_API_HOSTENT_STORAGE 0
#endif
/** define "hostent" variables storage */
#if LWIP_DNS_API_HOSTENT_STORAGE
#define HOSTENT_STORAGE
#else
#define HOSTENT_STORAGE static
#endif /* LWIP_DNS_API_STATIC_HOSTENT */
/**
* Returns an entry containing addresses of address family AF_INET
* for the host with name name.
* Due to dns_gethostbyname limitations, only one address is returned.
*
* @param name the hostname to resolve
* @return an entry containing addresses of address family AF_INET
* for the host with name name
*/
struct hostent*
lwip_gethostbyname(const char *name)
{
err_t err;
struct ip_addr addr;
/* buffer variables for lwip_gethostbyname() */
HOSTENT_STORAGE struct hostent s_hostent;
HOSTENT_STORAGE char *s_aliases;
HOSTENT_STORAGE struct ip_addr s_hostent_addr;
HOSTENT_STORAGE struct ip_addr *s_phostent_addr;
/* query host IP address */
err = netconn_gethostbyname(name, &addr);
if (err != ERR_OK) {
LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
h_errno = HOST_NOT_FOUND;
return NULL;
}
/* fill hostent */
s_hostent_addr = addr;
s_phostent_addr = &s_hostent_addr;
s_hostent.h_name = (char*)name;
s_hostent.h_aliases = &s_aliases;
s_hostent.h_addrtype = AF_INET;
s_hostent.h_length = sizeof(struct ip_addr);
s_hostent.h_addr_list = (char**)&s_phostent_addr;
#if DNS_DEBUG
/* dump hostent */
LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name == %s\n", s_hostent.h_name));
LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases == 0x%08lX\n",(u32_t)(s_hostent.h_aliases)));
if (s_hostent.h_aliases != NULL) {
u8_t idx;
for ( idx=0; s_hostent.h_aliases[idx]; idx++) {
LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == 0x%08lX\n", idx, s_hostent.h_aliases[idx]));
LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == %s\n", idx, s_hostent.h_aliases[idx]));
}
}
LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addrtype == %lu\n", (u32_t)(s_hostent.h_addrtype)));
LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_length == %lu\n", (u32_t)(s_hostent.h_length)));
LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list == 0x%08lX\n", s_hostent.h_addr_list));
if (s_hostent.h_addr_list != NULL) {
u8_t idx;
for ( idx=0; s_hostent.h_addr_list[idx]; idx++) {
LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i] == 0x%08lX\n", idx, s_hostent.h_addr_list[idx]));
LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]-> == %s\n", idx, inet_ntoa(*((struct in_addr*)(s_hostent.h_addr_list[idx])))));
}
}
#endif /* DNS_DEBUG */
#if LWIP_DNS_API_HOSTENT_STORAGE
/* this function should return the "per-thread" hostent after copy from s_hostent */
return sys_thread_hostent(&s_hostent);
#else
return &s_hostent;
#endif /* LWIP_DNS_API_HOSTENT_STORAGE */
}
/**
* Thread-safe variant of lwip_gethostbyname: instead of using a static
* buffer, this function takes buffer and errno pointers as arguments
* and uses these for the result.
*
* @param name the hostname to resolve
* @param ret pre-allocated struct where to store the result
* @param buf pre-allocated buffer where to store additional data
* @param buflen the size of buf
* @param result pointer to a hostent pointer that is set to ret on success
* and set to zero on error
* @param h_errnop pointer to an int where to store errors (instead of modifying
* the global h_errno)
* @return 0 on success, non-zero on error, additional error information
* is stored in *h_errnop instead of h_errno to be thread-safe
*/
int
lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
size_t buflen, struct hostent **result, int *h_errnop)
{
err_t err;
struct gethostbyname_r_helper *h;
char *hostname;
size_t namelen;
int lh_errno;
if (h_errnop == NULL) {
/* ensure h_errnop is never NULL */
h_errnop = &lh_errno;
}
if (result == NULL) {
/* not all arguments given */
*h_errnop = EINVAL;
return -1;
}
/* first thing to do: set *result to nothing */
*result = NULL;
if ((name == NULL) || (ret == NULL) || (buf == 0)) {
/* not all arguments given */
*h_errnop = EINVAL;
return -1;
}
namelen = strlen(name);
if (buflen < (sizeof(struct gethostbyname_r_helper) + namelen + 1 + (MEM_ALIGNMENT - 1))) {
/* buf can't hold the data needed + a copy of name */
*h_errnop = ERANGE;
return -1;
}
h = (struct gethostbyname_r_helper*)LWIP_MEM_ALIGN(buf);
hostname = ((char*)h) + sizeof(struct gethostbyname_r_helper);
/* query host IP address */
err = netconn_gethostbyname(name, &(h->addr));
if (err != ERR_OK) {
LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
*h_errnop = ENSRNOTFOUND;
return -1;
}
/* copy the hostname into buf */
MEMCPY(hostname, name, namelen);
hostname[namelen] = 0;
/* fill hostent */
h->addrs = &(h->addr);
h->aliases = NULL;
ret->h_name = (char*)hostname;
ret->h_aliases = &(h->aliases);
ret->h_addrtype = AF_INET;
ret->h_length = sizeof(struct ip_addr);
ret->h_addr_list = (char**)&(h->addrs);
/* set result != NULL */
*result = ret;
/* return success */
return 0;
}
/**
* Frees one or more addrinfo structures returned by getaddrinfo(), along with
* any additional storage associated with those structures. If the ai_next field
* of the structure is not null, the entire list of structures is freed.
*
* @param ai struct addrinfo to free
*/
void
lwip_freeaddrinfo(struct addrinfo *ai)
{
struct addrinfo *next;
while (ai != NULL) {
if (ai->ai_addr != NULL) {
mem_free(ai->ai_addr);
}
if (ai->ai_canonname != NULL) {
mem_free(ai->ai_canonname);
}
next = ai->ai_next;
mem_free(ai);
ai = next;
}
}
/**
* Translates the name of a service location (for example, a host name) and/or
* a service name and returns a set of socket addresses and associated
* information to be used in creating a socket with which to address the
* specified service.
* Memory for the result is allocated internally and must be freed by calling
* lwip_freeaddrinfo()!
*
* Due to a limitation in dns_gethostbyname, only the first address of a
* host is returned.
* Also, service names are not supported (only port numbers)!
*
* @param nodename descriptive name or address string of the host
* (may be NULL -> local address)
* @param servname port number as string of NULL
* @param hints structure containing input values that set socktype and protocol
* @param res pointer to a pointer where to store the result (set to NULL on failure)
* @return 0 on success, non-zero on failure
*/
int
lwip_getaddrinfo(const char *nodename, const char *servname,
const struct addrinfo *hints, struct addrinfo **res)
{
err_t err;
struct ip_addr addr;
struct addrinfo *ai;
struct sockaddr_in *sa = NULL;
int port_nr = 0;
if (res == NULL) {
return EAI_FAIL;
}
*res = NULL;
if ((nodename == NULL) && (servname == NULL)) {
return EAI_NONAME;
}
if (servname != NULL) {
/* service name specified: convert to port number
* @todo?: currently, only ASCII integers (port numbers) are supported! */
port_nr = atoi(servname);
if ((port_nr <= 0) || (port_nr > 0xffff)) {
return EAI_SERVICE;
}
}
if (nodename != NULL) {
/* service location specified, try to resolve */
err = netconn_gethostbyname(nodename, &addr);
if (err != ERR_OK) {
return EAI_FAIL;
}
} else {
/* service location specified, use loopback address */
addr.addr = INADDR_LOOPBACK;
}
ai = mem_malloc(sizeof(struct addrinfo));
if (ai == NULL) {
goto memerr;
}
memset(ai, 0, sizeof(struct addrinfo));
sa = mem_malloc(sizeof(struct sockaddr_in));
if (sa == NULL) {
goto memerr;
}
memset(sa, 0, sizeof(struct sockaddr_in));
/* set up sockaddr */
sa->sin_addr.s_addr = addr.addr;
sa->sin_family = AF_INET;
sa->sin_len = sizeof(struct sockaddr_in);
sa->sin_port = htons(port_nr);
/* set up addrinfo */
ai->ai_family = AF_INET;
if (hints != NULL) {
/* copy socktype & protocol from hints if specified */
ai->ai_socktype = hints->ai_socktype;
ai->ai_protocol = hints->ai_protocol;
}
if (nodename != NULL) {
/* copy nodename to canonname if specified */
size_t namelen = strlen(nodename);
ai->ai_canonname = mem_malloc(namelen + 1);
if (ai->ai_canonname == NULL) {
goto memerr;
}
MEMCPY(ai->ai_canonname, nodename, namelen);
ai->ai_canonname[namelen] = 0;
}
ai->ai_addrlen = sizeof(struct sockaddr_in);
ai->ai_addr = (struct sockaddr*)sa;
*res = ai;
return 0;
memerr:
if (ai != NULL) {
mem_free(ai);
}
if (sa != NULL) {
mem_free(sa);
}
return EAI_MEMORY;
}
#endif /* LWIP_DNS && LWIP_SOCKET */