curl/lib/hostip.h
Daniel Stenberg 6fdbb01194 Lots of work and analysis by "xbx___" in bug #1431750
(http://curl.haxx.se/bug/view.cgi?id=1431750) helped me identify and fix two
different but related bugs:

1) Removing an easy handle from a multi handle before the transfer is done
   could leave a connection in the connection cache for that handle that is
   in a state that isn't suitable for re-use. A subsequent re-use could then
   read from a NULL pointer and segfault.

2) When an easy handle was removed from the multi handle, there could be an
   outstanding c-ares DNS name resolve request. When the response arrived,
   it caused havoc since the connection struct it "belonged" to could've
   been freed already.

Now Curl_done() is called when an easy handle is removed from a multi handle
pre-maturely (that is, before the transfer was complteted). Curl_done() also
makes sure to cancel all (if any) outstanding c-ares requests.
2006-02-23 12:20:48 +00:00

261 lines
8.2 KiB
C

#ifndef __HOSTIP_H
#define __HOSTIP_H
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2006, 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"
/*
* Setup comfortable CURLRES_* defines to use in the host*.c sources.
*/
#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
#ifdef CURLRES_IPV4
#if !defined(HAVE_GETHOSTBYNAME_R) || defined(CURLRES_ASYNCH)
/* If built for ipv4 and missing gethostbyname_r(), or if using async name
resolve, we need the Curl_addrinfo_copy() function (which itself needs the
Curl_hostent_relocate() function)) */
#define CURLRES_ADDRINFO_COPY
#endif
#endif /* IPv4-only */
#ifndef CURLRES_ASYNCH
#define CURLRES_SYNCH
#endif
#ifndef USE_LIBIDN
#define CURLRES_IDN
#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
#else
#define CURL_ASYNC_SUCCESS CURLE_OK
#define ares_cancel(x)
#endif
/*
* Curl_addrinfo MUST be used for all name resolved info.
*/
#ifdef CURLRES_IPV6
typedef struct addrinfo Curl_addrinfo;
#else
/* OK, so some ipv4-only include tree probably have the addrinfo struct, but
to work even on those that don't, we provide our own look-alike! */
struct Curl_addrinfo {
int ai_flags;
int ai_family;
int ai_socktype;
int ai_protocol;
size_t ai_addrlen;
struct sockaddr *ai_addr;
char *ai_canonname;
struct Curl_addrinfo *ai_next;
};
typedef struct Curl_addrinfo Curl_addrinfo;
#endif
struct addrinfo;
struct hostent;
struct SessionHandle;
struct connectdata;
void Curl_global_host_cache_init(void);
void Curl_global_host_cache_dtor(void);
struct curl_hash *Curl_global_host_cache_get(void);
#define Curl_global_host_cache_use(__p) ((__p)->set.global_dns_cache)
struct Curl_dns_entry {
Curl_addrinfo *addr;
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_ERROR -1
#define CURLRESOLV_RESOLVED 0
#define CURLRESOLV_PENDING 1
int Curl_resolv(struct connectdata *conn, char *hostname,
int port, struct Curl_dns_entry **dnsentry);
/*
* 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,
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_fdset() 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 curl_multi_fdset() function */
CURLcode Curl_resolv_fdset(struct connectdata *conn,
fd_set *read_fd_set,
fd_set *write_fd_set,
int *max_fdp);
/* 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);
/* free name info */
void Curl_freeaddrinfo(Curl_addrinfo *freeaddr);
/* 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);
#ifdef CURLDEBUG
void curl_dofreeaddrinfo(struct addrinfo *freethis,
int line, const char *source);
int curl_dogetaddrinfo(char *hostname, char *service,
struct addrinfo *hints,
struct addrinfo **result,
int line, const char *source);
int curl_dogetnameinfo(const struct sockaddr *sa, socklen_t salen,
char *host, size_t hostlen,
char *serv, size_t servlen, int flags,
int line, const char *source);
#endif
/* This is the callback function that is used when we build with asynch
resolve, ipv4 */
CURLcode Curl_addrinfo4_callback(void *arg,
int status,
struct hostent *hostent);
/* This is the callback function that is used when we build with asynch
resolve, ipv6 */
CURLcode Curl_addrinfo6_callback(void *arg,
int status,
struct addrinfo *ai);
/* [ipv4 only] Creates a Curl_addrinfo struct from a numerical-only IP
address */
Curl_addrinfo *Curl_ip2addr(in_addr_t num, char *hostname, int port);
/* [ipv4 only] Curl_he2ai() converts a struct hostent to a Curl_addrinfo chain
and returns it */
Curl_addrinfo *Curl_he2ai(struct hostent *, int port);
/* relocate a hostent struct */
void Curl_hostent_relocate(struct hostent *h, long offset);
/* Clone a Curl_addrinfo struct, works protocol independently */
Curl_addrinfo *Curl_addrinfo_copy(void *orig, int port);
/*
* 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,
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
#endif