curl/lib/hostip.h

#ifndef __HOSTIP_H
#define __HOSTIP_H
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2010, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * $Id$
 ***************************************************************************/

#include "setup.h"
#include "hash.h"
#include "curl_addrinfo.h"

#ifdef HAVE_SETJMP_H
#include <setjmp.h>
#endif

#ifdef NETWARE
#undef in_addr_t
#define in_addr_t unsigned long
#endif

/*
 * Setup comfortable CURLRES_* defines to use in the host*.c sources.
 */

#ifdef USE_ARES
#include <ares_version.h>
#endif

#ifdef USE_ARES
#define CURLRES_ASYNCH
#define CURLRES_ARES
#endif

#ifdef USE_THREADING_GETHOSTBYNAME
#define CURLRES_ASYNCH
#define CURLRES_THREADED
#endif

#ifdef USE_THREADING_GETADDRINFO
#define CURLRES_ASYNCH
#define CURLRES_THREADED
#endif

#ifdef ENABLE_IPV6
#define CURLRES_IPV6
#else
#define CURLRES_IPV4
#endif

#ifndef CURLRES_ASYNCH
#define CURLRES_SYNCH
#endif

/* Allocate enough memory to hold the full name information structs and
 * everything. OSF1 is known to require at least 8872 bytes. The buffer
 * required for storing all possible aliases and IP numbers is according to
 * Stevens' Unix Network Programming 2nd edition, p. 304: 8192 bytes!
 */
#define CURL_HOSTENT_SIZE 9000

#define CURL_TIMEOUT_RESOLVE 300 /* when using asynch methods, we allow this
                                    many seconds for a name resolve */

#ifdef CURLRES_ARES
#define CURL_ASYNC_SUCCESS ARES_SUCCESS
#if ARES_VERSION >= 0x010500
/* c-ares 1.5.0 or later, the callback proto is modified */
#define HAVE_CARES_CALLBACK_TIMEOUTS 1
#endif
#else
#define CURL_ASYNC_SUCCESS CURLE_OK
#define ares_cancel(x) do {} while(0)
#define ares_destroy(x) do {} while(0)
#endif

struct addrinfo;
struct hostent;
struct SessionHandle;
struct connectdata;

/*
 * Curl_global_host_cache_init() initializes and sets up a global DNS cache.
 * Global DNS cache is general badness. Do not use. This will be removed in
 * a future version. Use the share interface instead!
 *
 * Returns a struct curl_hash pointer on success, NULL on failure.
 */
struct curl_hash *Curl_global_host_cache_init(void);
void Curl_global_host_cache_dtor(void);

struct Curl_dns_entry {
  Curl_addrinfo *addr;
  /* timestamp == 0 -- entry not in hostcache
     timestamp != 0 -- entry is in hostcache */
  time_t timestamp;
  long inuse;      /* use-counter, make very sure you decrease this
                      when you're done using the address you received */
};

/*
 * Curl_resolv() returns an entry with the info for the specified host
 * and port.
 *
 * The returned data *MUST* be "unlocked" with Curl_resolv_unlock() after
 * use, or we'll leak memory!
 */
/* return codes */
#define CURLRESOLV_TIMEDOUT -2
#define CURLRESOLV_ERROR    -1
#define CURLRESOLV_RESOLVED  0
#define CURLRESOLV_PENDING   1
int Curl_resolv(struct connectdata *conn, const char *hostname,
                int port, struct Curl_dns_entry **dnsentry);
int Curl_resolv_timeout(struct connectdata *conn, const char *hostname,
                        int port, struct Curl_dns_entry **dnsentry,
                        long timeoutms);

/*
 * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've
 * been set and returns TRUE if they are OK.
 */
bool Curl_ipvalid(struct SessionHandle *data);

/*
 * Curl_getaddrinfo() is the generic low-level name resolve API within this
 * source file. There are several versions of this function - for different
 * name resolve layers (selected at build-time). They all take this same set
 * of arguments
 */
Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
                                const char *hostname,
                                int port,
                                int *waitp);

CURLcode Curl_is_resolved(struct connectdata *conn,
                          struct Curl_dns_entry **dns);
CURLcode Curl_wait_for_resolv(struct connectdata *conn,
                              struct Curl_dns_entry **dnsentry);

/* Curl_resolv_getsock() is a generic function that exists in multiple
   versions depending on what name resolve technology we've built to use. The
   function is called from the multi_getsock() function.  'sock' is a pointer
   to an array to hold the file descriptors, with 'numsock' being the size of
   that array (in number of entries). This function is supposed to return
   bitmask indicating what file descriptors (referring to array indexes in the
   'sock' array) to wait for, read/write. */
int Curl_resolv_getsock(struct connectdata *conn, curl_socket_t *sock,
                        int numsocks);

/* unlock a previously resolved dns entry */
void Curl_resolv_unlock(struct SessionHandle *data,
                        struct Curl_dns_entry *dns);

/* for debugging purposes only: */
void Curl_scan_cache_used(void *user, void *ptr);

/* make a new dns cache and return the handle */
struct curl_hash *Curl_mk_dnscache(void);

/* prune old entries from the DNS cache */
void Curl_hostcache_prune(struct SessionHandle *data);

/* Return # of adresses in a Curl_addrinfo struct */
int Curl_num_addresses (const Curl_addrinfo *addr);

#if defined(CURLDEBUG) && defined(HAVE_GETNAMEINFO)
int curl_dogetnameinfo(GETNAMEINFO_QUAL_ARG1 GETNAMEINFO_TYPE_ARG1 sa,
                       GETNAMEINFO_TYPE_ARG2 salen,
                       char *host, GETNAMEINFO_TYPE_ARG46 hostlen,
                       char *serv, GETNAMEINFO_TYPE_ARG46 servlen,
                       GETNAMEINFO_TYPE_ARG7 flags,
                       int line, const char *source);
#endif

/*
 * Curl_addrinfo_callback() is used when we build with any asynch specialty.
 * Handles end of async request processing. Inserts ai into hostcache when
 * status is CURL_ASYNC_SUCCESS. Twiddles fields in conn to indicate async
 * request completed wether successfull or failed.
 */
CURLcode Curl_addrinfo_callback(struct connectdata *conn,
                                int status,
                                Curl_addrinfo *ai);

/*
 * Curl_printable_address() returns a printable version of the 1st address
 * given in the 'ip' argument. The result will be stored in the buf that is
 * bufsize bytes big.
 */
const char *Curl_printable_address(const Curl_addrinfo *ip,
                                   char *buf, size_t bufsize);

/*
 * Curl_cache_addr() stores a 'Curl_addrinfo' struct in the DNS cache.
 *
 * Returns the Curl_dns_entry entry pointer or NULL if the storage failed.
 */
struct Curl_dns_entry *
Curl_cache_addr(struct SessionHandle *data, Curl_addrinfo *addr,
                const char *hostname, int port);

/*
 * Curl_destroy_thread_data() cleans up async resolver data.
 * Complementary of ares_destroy.
 */
struct Curl_async; /* forward-declaration */
void Curl_destroy_thread_data(struct Curl_async *async);

#ifndef INADDR_NONE
#define CURL_INADDR_NONE (in_addr_t) ~0
#else
#define CURL_INADDR_NONE INADDR_NONE
#endif

#ifdef HAVE_SIGSETJMP
/* Forward-declaration of variable defined in hostip.c. Beware this
 * is a global and unique instance. This is used to store the return
 * address that we can jump back to from inside a signal handler.
 * This is not thread-safe stuff.
 */
extern sigjmp_buf curl_jmpenv;
#endif

#endif