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lwIP
2.2.1
Lightweight IP stack
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#include "lwip/netdb.h"#include "lwip/err.h"#include "lwip/errno.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 |
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 LWIP_DNS_API_HOSTENT_STORAGE 0 |
LWIP_DNS_API_HOSTENT_STORAGE: if set to 0 (default), lwip_gethostbyname() returns the same global variable for all calls (in all threads). When set to 1, your port should provide a function struct hostent* sys_thread_hostent( struct hostent* h); which have to do a copy of "h" and return a pointer ont the "per-thread" copy.
| 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.