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044755b30f
curl/lib/hostip.c
Daniel Stenberg 8927ddec16 In order to not get problems with DNS cache pruning, we no longer store 
any name resolved data in any curl handle struct. That way, we won't mind
if the cache entries are pruned for the next time we need them. We'll just
resolve them again instead.

This changes the Curl_resolv() proto. It modifies the SessionHandle struct
but perhaps most importantly, it'll make the internals somewhat dependent
on the DNS cache not being disabled as that will cripple operations somewhat.
Especially for persistant connections.
2002-04-25 19:00:57 +00:00

620 lines
16 KiB
C
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/*****************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2002, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* In order to be useful for every potential user, curl and libcurl are
* dual-licensed under the MPL and the MIT/X-derivate licenses.
*
* 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 MPL or the MIT/X-derivate
* licenses. You may pick one of these licenses.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* $Id$
*****************************************************************************/
#include "setup.h"
#include <string.h>
#include <errno.h>
#define _REENTRANT
#if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
#include <winsock.h>
#else
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h> /* required for free() prototypes */
#endif
#ifdef VMS
#include <in.h>
#include <inet.h>
#include <stdlib.h>
#endif
#endif
#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "hash.h"
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
#if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL)
#include "inet_ntoa_r.h"
#endif
/* The last #include file should be: */
#ifdef MALLOCDEBUG
#include "memdebug.h"
#endif
static curl_hash hostname_cache;
static int host_cache_initialized;
void Curl_global_host_cache_init(void)
{
if (!host_cache_initialized) {
curl_hash_init(&hostname_cache, 7, Curl_freeaddrinfo);
host_cache_initialized = 1;
}
}
curl_hash *Curl_global_host_cache_get(void)
{
return &hostname_cache;
}
void Curl_global_host_cache_dtor(void)
{
if (host_cache_initialized) {
curl_hash_clean(&hostname_cache);
host_cache_initialized = 0;
}
}
struct curl_dns_cache_entry {
Curl_addrinfo *addr;
time_t timestamp;
};
/* count the number of characters that an integer takes up */
static int _num_chars(int i)
{
int chars = 0;
/* While the number divided by 10 is greater than one,
* re-divide the number by 10, and increment the number of
* characters by 1.
*
* this relies on the fact that for every multiple of 10,
* a new digit is added onto every number
*/
do {
chars++;
i = (int) i / 10;
} while (i >= 1);
return chars;
}
/* Create a hostcache id */
static char *
_create_hostcache_id(char *server, int port, ssize_t *entry_len)
{
char *id = NULL;
/* Get the length of the new entry id */
*entry_len = *entry_len + /* Hostname length */
1 + /* The ':' seperator */
_num_chars(port); /* The number of characters the port will take up */
/* Allocate the new entry id */
id = malloc(*entry_len + 1);
if (!id) {
return NULL;
}
/* Create the new entry */
/* If sprintf() doesn't return the entry length, that signals failure */
if (sprintf(id, "%s:%d", server, port) != *entry_len) {
/* Free the allocated id, set length to zero and return NULL */
*entry_len = 0;
free(id);
return NULL;
}
return id;
}
struct _curl_hostcache_prune_data {
int cache_timeout;
int now;
};
static int
_curl_hostcache_timestamp_remove(void *datap, void *hc)
{
struct _curl_hostcache_prune_data *data =
(struct _curl_hostcache_prune_data *) datap;
struct curl_dns_cache_entry *c = (struct curl_dns_cache_entry *) hc;
if (data->now - c->timestamp < data->cache_timeout) {
return 0;
}
return 1;
}
static void
_curl_hostcache_prune(curl_hash *hostcache, int cache_timeout, int now)
{
struct _curl_hostcache_prune_data user;
user.cache_timeout = cache_timeout;
user.now = now;
curl_hash_clean_with_criterium(hostcache,
(void *) &user,
_curl_hostcache_timestamp_remove);
}
/* Macro to save redundant free'ing of entry_id */
#define _hostcache_return(__v) \
{ \
free(entry_id); \
return (__v); \
}
Curl_addrinfo *Curl_resolv(struct SessionHandle *data,
char *hostname,
int port)
{
char *entry_id = NULL;
struct curl_dns_cache_entry *p = NULL;
ssize_t entry_len;
time_t now;
char *bufp;
/* If the host cache timeout is 0, we don't do DNS cach'ing
so fall through */
if (data->set.dns_cache_timeout == 0) {
return Curl_getaddrinfo(data, hostname, port, &bufp);
}
time(&now);
/* Remove outdated entries from the hostcache */
_curl_hostcache_prune(data->hostcache,
data->set.dns_cache_timeout,
now);
/* Create an entry id, based upon the hostname and port */
entry_len = strlen(hostname);
entry_id = _create_hostcache_id(hostname, port, &entry_len);
/* If we can't create the entry id, don't cache, just fall-through
to the plain Curl_getaddrinfo() */
if (!entry_id) {
return Curl_getaddrinfo(data, hostname, port, &bufp);
}
/* See if its already in our dns cache */
if (entry_id &&
curl_hash_find(data->hostcache, entry_id, entry_len+1, (void **) &p)) {
_hostcache_return(p->addr);
}
/* Create a new cache entry */
p = (struct curl_dns_cache_entry *)
malloc(sizeof(struct curl_dns_cache_entry));
if (!p) {
_hostcache_return(NULL);
}
p->addr = Curl_getaddrinfo(data, hostname, port, &bufp);
if (!p->addr) {
free(p);
_hostcache_return(NULL);
}
p->timestamp = now;
/* Save it in our host cache */
curl_hash_update(data->hostcache, entry_id, entry_len+1, (const void *) p);
_hostcache_return(p->addr);
}
/*
* This is a wrapper function for freeing name information in a protocol
* independent way. This takes care of using the appropriate underlaying
* proper function.
*/
void Curl_freeaddrinfo(void *freethis)
{
struct curl_dns_cache_entry *p = (struct curl_dns_cache_entry *) freethis;
#ifdef ENABLE_IPV6
freeaddrinfo(p->addr);
#else
free(p->addr);
#endif
free(p);
}
/* --- resolve name or IP-number --- */
#ifdef ENABLE_IPV6
#ifdef MALLOCDEBUG
/* These two are strictly for memory tracing and are using the same
* style as the family otherwise present in memdebug.c. I put these ones
* here since they require a bunch of struct types I didn't wanna include
* in memdebug.c
*/
int curl_getaddrinfo(char *hostname, char *service,
struct addrinfo *hints,
struct addrinfo **result,
int line, const char *source)
{
int res=(getaddrinfo)(hostname, service, hints, result);
if(0 == res) {
/* success */
if(logfile)
fprintf(logfile, "ADDR %s:%d getaddrinfo() = %p\n",
source, line, (void *)*result);
}
else {
if(logfile)
fprintf(logfile, "ADDR %s:%d getaddrinfo() failed\n",
source, line);
}
return res;
}
void curl_freeaddrinfo(struct addrinfo *freethis,
int line, const char *source)
{
(freeaddrinfo)(freethis);
if(logfile)
fprintf(logfile, "ADDR %s:%d freeaddrinfo(%p)\n",
source, line, (void *)freethis);
}
#endif
/*
* Return name information about the given hostname and port number. If
* successful, the 'addrinfo' is returned and the forth argument will point to
* memory we need to free after use. That meory *MUST* be freed with
* Curl_freeaddrinfo(), nothing else.
*/
Curl_addrinfo *Curl_getaddrinfo(struct SessionHandle *data,
char *hostname,
int port,
char **bufp)
{
struct addrinfo hints, *res;
int error;
char sbuf[NI_MAXSERV];
int s, pf = PF_UNSPEC;
/* see if we have an IPv6 stack */
s = socket(PF_INET6, SOCK_DGRAM, 0);
if (s < 0)
/* Some non-IPv6 stacks have been found to make very slow name resolves
* when PF_UNSPEC is used, so thus we switch to a mere PF_INET lookup if
* the stack seems to be a non-ipv6 one. */
pf = PF_INET;
else
/* This seems to be an IPv6-capable stack, use PF_UNSPEC for the widest
* possible checks. And close the socket again.
*/
sclose(s);
memset(&hints, 0, sizeof(hints));
hints.ai_family = pf;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_CANONNAME;
snprintf(sbuf, sizeof(sbuf), "%d", port);
error = getaddrinfo(hostname, sbuf, &hints, &res);
if (error) {
infof(data, "getaddrinfo(3) failed for %s\n", hostname);
return NULL;
}
*bufp=(char *)res; /* make it point to the result struct */
return res;
}
#else /* following code is IPv4-only */
#ifndef HAVE_GETHOSTBYNAME_R
/**
* Performs a "deep" copy of a hostent into a buffer (returns a pointer to the
* copy). Make absolutely sure the destination buffer is big enough!
*
* Keith McGuigan
* 10/3/2001 */
static struct hostent* pack_hostent(char** buf, struct hostent* orig)
{
char* bufptr;
struct hostent* copy;
int i;
char* str;
int len;
bufptr = *buf;
copy = (struct hostent*)bufptr;
bufptr += sizeof(struct hostent);
copy->h_name = bufptr;
len = strlen(orig->h_name) + 1;
strncpy(bufptr, orig->h_name, len);
bufptr += len;
/* we align on even 64bit boundaries for safety */
#define MEMALIGN(x) ((x)+(8-(((unsigned long)(x))&0x7)))
/* This must be aligned properly to work on many CPU architectures! */
bufptr = MEMALIGN(bufptr);
copy->h_aliases = (char**)bufptr;
/* Figure out how many aliases there are */
for (i = 0; orig->h_aliases[i] != NULL; ++i);
/* Reserve room for the array */
bufptr += (i + 1) * sizeof(char*);
/* Clone all known aliases */
for(i = 0; (str = orig->h_aliases[i]); i++) {
len = strlen(str) + 1;
strncpy(bufptr, str, len);
copy->h_aliases[i] = bufptr;
bufptr += len;
}
/* Terminate the alias list with a NULL */
copy->h_aliases[i] = NULL;
copy->h_addrtype = orig->h_addrtype;
copy->h_length = orig->h_length;
/* align it for (at least) 32bit accesses */
bufptr = MEMALIGN(bufptr);
copy->h_addr_list = (char**)bufptr;
/* Figure out how many addresses there are */
for (i = 0; orig->h_addr_list[i] != NULL; ++i);
/* Reserve room for the array */
bufptr += (i + 1) * sizeof(char*);
i = 0;
len = orig->h_length;
str = orig->h_addr_list[i];
while (str != NULL) {
memcpy(bufptr, str, len);
copy->h_addr_list[i] = bufptr;
bufptr += len;
str = orig->h_addr_list[++i];
}
copy->h_addr_list[i] = NULL;
*buf=(char *)realloc(*buf, (int)bufptr-(int)(*buf));
return copy;
}
#endif
static char *MakeIP(unsigned long num,char *addr, int addr_len)
{
#if defined(HAVE_INET_NTOA) || defined(HAVE_INET_NTOA_R)
struct in_addr in;
in.s_addr = htonl(num);
#if defined(HAVE_INET_NTOA_R)
inet_ntoa_r(in,addr,addr_len);
#else
strncpy(addr,inet_ntoa(in),addr_len);
#endif
#else
unsigned char *paddr;
num = htonl(num); /* htonl() added to avoid endian probs */
paddr = (unsigned char *)&num;
sprintf(addr, "%u.%u.%u.%u", paddr[0], paddr[1], paddr[2], paddr[3]);
#endif
return (addr);
}
/* The original code to this function was once stolen from the Dancer source
code, written by Bjorn Reese, it has since been patched and modified
considerably. */
#ifndef INADDR_NONE
#define INADDR_NONE (in_addr_t) ~0
#endif
Curl_addrinfo *Curl_getaddrinfo(struct SessionHandle *data,
char *hostname,
int port,
char **bufp)
{
struct hostent *h = NULL;
in_addr_t in;
int ret; /* this variable is unused on several platforms but used on some */
#define CURL_NAMELOOKUP_SIZE 9000
/* 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 editor, p. 304: 8192 bytes! */
port=0; /* unused in IPv4 code */
ret = 0; /* to prevent the compiler warning */
if ( (in=inet_addr(hostname)) != INADDR_NONE ) {
struct in_addr *addrentry;
int *buf = (int *)malloc(128);
if(!buf)
return NULL; /* major failure */
*bufp = (char *)buf;
h = (struct hostent*)buf;
h->h_addr_list = (char**)(buf + sizeof(*h));
addrentry = (struct in_addr*)(h->h_addr_list + 2);
addrentry->s_addr = in;
h->h_addr_list[0] = (char*)addrentry;
h->h_addr_list[1] = NULL;
h->h_addrtype = AF_INET;
h->h_length = sizeof(*addrentry);
h->h_name = *(h->h_addr_list) + h->h_length;
/* bad one h->h_name = (char*)(h->h_addr_list + h->h_length); */
MakeIP(ntohl(in),h->h_name, 128 - (long)(h->h_name) + (long)buf);
}
#if defined(HAVE_GETHOSTBYNAME_R)
else {
int h_errnop;
int res=ERANGE;
int step_size=200;
int *buf = (int *)malloc(CURL_NAMELOOKUP_SIZE);
if(!buf)
return NULL; /* major failure */
*bufp=(char *)buf;
/* Workaround for gethostbyname_r bug in qnx nto. It is also _required_
for some of these functions. */
memset(buf, 0, CURL_NAMELOOKUP_SIZE);
#ifdef HAVE_GETHOSTBYNAME_R_5
/* Solaris, IRIX and more */
while(!h) {
h = gethostbyname_r(hostname,
(struct hostent *)buf,
(char *)buf + sizeof(struct hostent),
step_size - sizeof(struct hostent),
&h_errnop);
/* If the buffer is too small, it returns NULL and sets errno to
ERANGE. The errno is thread safe if this is compiled with
-D_REENTRANT as then the 'errno' variable is a macro defined to
get used properly for threads. */
if(h || (errno != ERANGE))
break;
step_size+=200;
}
#ifdef MALLOCDEBUG
infof(data, "gethostbyname_r() uses %d bytes\n", step_size);
#endif
if(h) {
buf=(int *)realloc(buf, step_size);
*bufp=(char *)buf;
}
else
#endif
#ifdef HAVE_GETHOSTBYNAME_R_6
/* Linux */
while((res=gethostbyname_r(hostname,
(struct hostent *)buf,
(char *)buf + sizeof(struct hostent),
step_size - sizeof(struct hostent),
&h, /* DIFFERENCE */
&h_errnop))==ERANGE) {
step_size+=200;
}
#ifdef MALLOCDEBUG
infof(data, "gethostbyname_r() uses %d bytes\n", step_size);
#endif
if(!res) {
buf=(int *)realloc(buf, step_size);
*bufp=(char *)buf;
}
else
#endif
#ifdef HAVE_GETHOSTBYNAME_R_3
/* AIX, Digital Unix, HPUX 10, more? */
if(CURL_NAMELOOKUP_SIZE >=
(sizeof(struct hostent)+sizeof(struct hostent_data)))
/* August 22nd, 2000: Albert Chin-A-Young brought an updated version
* that should work! September 20: Richard Prescott worked on the buffer
* size dilemma. */
ret = gethostbyname_r(hostname,
(struct hostent *)buf,
(struct hostent_data *)(buf + sizeof(struct hostent)));
else
ret = -1; /* failure, too smallish buffer size */
/* result expected in h */
h = (struct hostent*)buf;
h_errnop= errno; /* we don't deal with this, but set it anyway */
if(ret)
#endif
{
infof(data, "gethostbyname_r(2) failed for %s\n", hostname);
h = NULL; /* set return code to NULL */
free(buf);
*bufp=NULL;
}
#else
else {
if ((h = gethostbyname(hostname)) == NULL ) {
infof(data, "gethostbyname(2) failed for %s\n", hostname);
*bufp=NULL;
}
else
{
char *buf=(char *)malloc(CURL_NAMELOOKUP_SIZE);
/* we make a copy of the hostent right now, right here, as the
static one we got a pointer to might get removed when we don't
want/expect that */
h = pack_hostent(&buf, h);
*bufp=(char *)buf;
}
#endif
}
return (h);
}
#endif /* end of IPv4-specific code */
/*
* local variables:
* eval: (load-file "../curl-mode.el")
* end:
* vim600: fdm=marker
* vim: et sw=2 ts=2 sts=2 tw=78
*/
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