lwIP
2.1.0
Lightweight IP stack
|
#include "lwip/netdb.h"
#include "lwip/err.h"
#include "lwip/mem.h"
#include "lwip/memp.h"
#include "lwip/ip_addr.h"
#include "lwip/api.h"
#include "lwip/dns.h"
#include <string.h>
#include <stdlib.h>
Data Structures | |
struct | gethostbyname_r_helper |
Macros | |
#define | LWIP_DNS_API_HOSTENT_STORAGE 0 |
#define | HOSTENT_STORAGE static |
Functions | |
struct hostent * | lwip_gethostbyname (const char *name) |
int | lwip_gethostbyname_r (const char *name, struct hostent *ret, char *buf, size_t buflen, struct hostent **result, int *h_errnop) |
void | lwip_freeaddrinfo (struct addrinfo *ai) |
int | lwip_getaddrinfo (const char *nodename, const char *servname, const struct addrinfo *hints, struct addrinfo **res) |
Variables | |
int | h_errno |
API functions for name resolving
#define HOSTENT_STORAGE static |
define "hostent" variables storage
#define LWIP_DNS_API_HOSTENT_STORAGE 0 |
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
void lwip_freeaddrinfo | ( | struct addrinfo * | ai | ) |
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.
ai | struct addrinfo to free |
int lwip_getaddrinfo | ( | const char * | nodename, |
const char * | servname, | ||
const struct addrinfo * | hints, | ||
struct addrinfo ** | res | ||
) |
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)!
nodename | descriptive name or address string of the host (may be NULL -> local address) |
servname | port number as string of NULL |
hints | structure containing input values that set socktype and protocol |
res | pointer to a pointer where to store the result (set to NULL on failure) |
struct hostent* lwip_gethostbyname | ( | const char * | name | ) |
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.
name | the hostname to resolve |
int lwip_gethostbyname_r | ( | const char * | name, |
struct hostent * | ret, | ||
char * | buf, | ||
size_t | buflen, | ||
struct hostent ** | result, | ||
int * | h_errnop | ||
) |
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.
name | the hostname to resolve |
ret | pre-allocated struct where to store the result |
buf | pre-allocated buffer where to store additional data |
buflen | the size of buf |
result | pointer to a hostent pointer that is set to ret on success and set to zero on error |
h_errnop | pointer to an int where to store errors (instead of modifying the global h_errno) |
int h_errno |
h_errno is exported in netdb.h for access by applications.