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ares awareness/usage/support added. If configure --enable-ares is used, we

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build libcurl to use ares for asynch name resolves.
This commit is contained in:
Daniel Stenberg
2003-08-05 14:40:59 +00:00
parent f85935f0f9
commit b73612392d
11 changed files with 629 additions and 182 deletions
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471
lib/hostip.c
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@@ -65,6 +65,7 @@
#include "hostip.h"
#include "hash.h"
#include "share.h"
#include "url.h"
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
@@ -81,10 +82,13 @@
static curl_hash hostname_cache;
static int host_cache_initialized;
static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
char *hostname,
int port,
char **bufp);
static Curl_addrinfo *my_getaddrinfo(struct connectdata *conn,
char *hostname,
int port,
int *waitp);
#if !defined(HAVE_GETHOSTBYNAME_R) || defined(USE_ARES)
static struct hostent* pack_hostent(char** buf, struct hostent* orig);
#endif
void Curl_global_host_cache_init(void)
{
@@ -135,15 +139,14 @@ 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 */
*entry_len = *entry_len + /* Hostname length */
1 + /* ':' seperator */
_num_chars(port); /* number of characters the port will take up */
/* Allocate the new entry id */
id = malloc(*entry_len + 1);
if (!id) {
if (!id)
return NULL;
}
/* Create the new entry */
/* If sprintf() doesn't return the entry length, that signals failure */
@@ -192,57 +195,26 @@ hostcache_prune(curl_hash *hostcache, int cache_timeout, int now)
hostcache_timestamp_remove);
}
#if defined(CURLDEBUG) && defined(AGGRESIVE_TEST)
/* Called from Curl_done() to check that there's no DNS cache entry with
a non-zero counter left. */
void Curl_scan_cache_used(void *user, void *ptr)
{
struct Curl_dns_entry *e = ptr;
(void)user; /* prevent compiler warning */
if(e->inuse) {
fprintf(stderr, "*** WARNING: locked DNS cache entry detected: %s\n",
e->entry_id);
/* perform a segmentation fault to draw attention */
*(void **)0 = 0;
}
}
#endif
/* Macro to save redundant free'ing of entry_id */
#define HOSTCACHE_RETURN(dns) \
{ \
free(entry_id); \
if(data->share) \
{ \
Curl_share_unlock(data, CURL_LOCK_DATA_DNS); \
} \
return dns; \
}
#ifdef HAVE_SIGSETJMP
/* Beware this is a global and unique instance */
sigjmp_buf curl_jmpenv;
#endif
struct Curl_dns_entry *Curl_resolv(struct SessionHandle *data,
char *hostname,
int port)
{
char *entry_id = NULL;
struct Curl_dns_entry *dns = NULL;
ssize_t entry_len;
time_t now;
char *bufp;
#ifdef HAVE_SIGSETJMP
/* this allows us to time-out from the name resolver, as the timeout
will generate a signal and we will siglongjmp() from that here */
if(!data->set.no_signal && sigsetjmp(curl_jmpenv, 1)) {
/* this is coming from a siglongjmp() */
failf(data, "name lookup timed out");
return NULL;
}
#endif
/* When calling Curl_resolv() has resulted in a response with a returned
address, we call this function to store the information in the dns
cache etc */
static struct Curl_dns_entry *
cache_resolv_response(struct SessionHandle *data,
Curl_addrinfo *addr,
char *hostname,
int port)
{
char *entry_id;
int entry_len;
struct Curl_dns_entry *dns;
time_t now;
/* Create an entry id, based upon the hostname and port */
entry_len = strlen(hostname);
@@ -251,45 +223,112 @@ struct Curl_dns_entry *Curl_resolv(struct SessionHandle *data,
if (!entry_id)
return NULL;
/* Create a new cache entry */
dns = (struct Curl_dns_entry *) malloc(sizeof(struct Curl_dns_entry));
if (!dns) {
Curl_freeaddrinfo(addr);
free(entry_id);
return NULL;
}
dns->inuse = 0;
dns->addr = addr;
/* Store it in our dns cache */
Curl_hash_add(data->hostcache, entry_id, entry_len+1,
(const void *) dns);
time(&now);
dns->timestamp = now;
dns->inuse++; /* mark entry as in-use */
/* Remove outdated and unused entries from the hostcache */
hostcache_prune(data->hostcache,
data->set.dns_cache_timeout,
now);
/* free the allocated entry_id again */
free(entry_id);
return dns;
}
/* Resolve a name and return a pointer in the 'entry' argument if one
is available.
Return codes:
-1 = error, no pointer
0 = OK, pointer provided
1 = waiting for response, no pointer
*/
int Curl_resolv(struct connectdata *conn,
char *hostname,
int port,
struct Curl_dns_entry **entry)
{
char *entry_id = NULL;
struct Curl_dns_entry *dns = NULL;
ssize_t entry_len;
int wait;
struct SessionHandle *data = conn->data;
/* default to failure */
int rc = -1;
*entry = NULL;
#ifdef HAVE_SIGSETJMP
/* this allows us to time-out from the name resolver, as the timeout
will generate a signal and we will siglongjmp() from that here */
if(!data->set.no_signal && sigsetjmp(curl_jmpenv, 1)) {
/* this is coming from a siglongjmp() */
failf(data, "name lookup timed out");
return -1;
}
#endif
/* 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, fail */
if (!entry_id)
return -1;
if(data->share)
Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
/* See if its already in our dns cache */
dns = Curl_hash_pick(data->hostcache, entry_id, entry_len+1);
/* free the allocated entry_id again */
free(entry_id);
if (!dns) {
Curl_addrinfo *addr = my_getaddrinfo(data, hostname, port, &bufp);
/* The entry was not in the cache. Resolve it to IP address */
/* If my_getaddrinfo() returns NULL, 'wait' might be set to a non-zero
value indicating that we need to wait for the response to the resolve
call */
Curl_addrinfo *addr = my_getaddrinfo(conn, hostname, port, &wait);
if (!addr) {
HOSTCACHE_RETURN(NULL);
if(wait)
/* the response to our resolve call will come asynchronously at
a later time, good or bad */
rc = 1;
}
/* Create a new cache entry */
dns = (struct Curl_dns_entry *) malloc(sizeof(struct Curl_dns_entry));
if (!dns) {
Curl_freeaddrinfo(addr);
HOSTCACHE_RETURN(NULL);
}
dns->inuse = 0;
dns->addr = addr;
/* Save it in our host cache */
Curl_hash_add(data->hostcache, entry_id, entry_len+1, (const void *) dns);
else
/* we got a response, store it in the cache */
dns = cache_resolv_response(data, addr, hostname, port);
}
time(&now);
dns->timestamp = now;
dns->inuse++; /* mark entry as in-use */
#ifdef CURLDEBUG
dns->entry_id = entry_id;
#endif
if(data->share)
Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
/* Remove outdated and unused entries from the hostcache */
hostcache_prune(data->hostcache,
data->set.dns_cache_timeout,
now);
*entry = dns;
HOSTCACHE_RETURN(dns);
return rc;
}
void Curl_resolv_unlock(struct SessionHandle *data, struct Curl_dns_entry *dns)
@@ -314,7 +353,7 @@ void Curl_freeaddrinfo(Curl_addrinfo *p)
#ifdef ENABLE_IPV6
freeaddrinfo(p);
#else
free(p);
free(p); /* works fine for the ARES case too */
#endif
}
@@ -332,7 +371,203 @@ void Curl_freednsinfo(void *freethis)
/* --- resolve name or IP-number --- */
#ifdef ENABLE_IPV6
/* 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_NAMELOOKUP_SIZE 9000
#ifdef USE_ARES
CURLcode Curl_multi_ares_fdset(struct connectdata *conn,
fd_set *read_fd_set,
fd_set *write_fd_set,
int *max_fdp)
{
int max = ares_fds(conn->data->state.areschannel,
read_fd_set, write_fd_set);
*max_fdp = max;
return CURLE_OK;
}
/* called to check if the name is resolved now */
CURLcode Curl_is_resolved(struct connectdata *conn, bool *done)
{
fd_set read_fds, write_fds;
static const struct timeval tv={0,0};
int count;
struct SessionHandle *data = conn->data;
int nfds = ares_fds(data->state.areschannel, &read_fds, &write_fds);
count = select(nfds, &read_fds, &write_fds, NULL,
(struct timeval *)&tv);
if(count)
ares_process(data->state.areschannel, &read_fds, &write_fds);
if(conn->async.done) {
*done = TRUE;
if(!conn->async.dns)
return CURLE_COULDNT_RESOLVE_HOST;
}
else
*done = FALSE;
return CURLE_OK;
}
/* This is a function that locks and waits until the name resolve operation
has completed.
If 'entry' is non-NULL, make it point to the resolved dns entry
Return CURLE_COULDNT_RESOLVE_HOST if the host was not resolved, and
CURLE_OPERATION_TIMEDOUT if a time-out occurred.
*/
CURLcode Curl_wait_for_resolv(struct connectdata *conn,
struct Curl_dns_entry **entry)
{
CURLcode rc=CURLE_OK;
struct SessionHandle *data = conn->data;
/* Wait for the name resolve query to complete. */
while (1) {
int nfds=0;
fd_set read_fds, write_fds;
struct timeval *tvp, tv;
int count;
FD_ZERO(&read_fds);
FD_ZERO(&write_fds);
nfds = ares_fds(data->state.areschannel, &read_fds, &write_fds);
if (nfds == 0)
break;
tvp = ares_timeout(data->state.areschannel,
NULL, /* pass in our maximum time here */
&tv);
count = select(nfds, &read_fds, &write_fds, NULL, tvp);
if (count < 0 && errno != EINVAL)
break;
ares_process(data->state.areschannel, &read_fds, &write_fds);
}
/* Operation complete, if the lookup was successful we now have the entry
in the cache. */
/* this destroys the channel and we cannot use it anymore after this */
ares_destroy(data->state.areschannel);
if(entry)
*entry = conn->async.dns;
if(!conn->async.dns) {
/* a name was not resolved */
if(conn->async.done)
rc = CURLE_COULDNT_RESOLVE_HOST;
else
rc = CURLE_OPERATION_TIMEDOUT;
/* close the connection, since we can't return failure here without
cleaning up this connection properly */
Curl_disconnect(conn);
}
return rc;
}
/* this function gets called by ares when we got the name resolved */
static void host_callback(void *arg, /* "struct connectdata *" */
int status,
struct hostent *hostent)
{
struct connectdata *conn = (struct connectdata *)arg;
struct Curl_dns_entry *dns = NULL;
conn->async.done = TRUE;
conn->async.status = status;
if(ARES_SUCCESS == status) {
/* we got a resolved name in 'hostent' */
char *bufp = (char *)malloc(CURL_NAMELOOKUP_SIZE);
if(bufp) {
/* pack_hostent() copies to and shrinks the target buffer */
struct hostent *he = pack_hostent(&bufp, hostent);
dns = cache_resolv_response(conn->data, he,
conn->async.hostname, conn->async.port);
}
}
conn->async.dns = dns;
/* The input hostent struct will be freed by ares when we return from this
function */
}
/*
* Return name information about the given hostname and port number. If
* successful, the 'hostent' 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.
*/
static Curl_addrinfo *my_getaddrinfo(struct connectdata *conn,
char *hostname,
int port,
int *waitp)
{
int rc;
char *bufp;
struct SessionHandle *data = conn->data;
rc = ares_init(&data->state.areschannel);
*waitp = FALSE;
if(!rc) {
/* only if success */
bufp = strdup(hostname);
if(bufp) {
Curl_safefree(conn->async.hostname);
conn->async.hostname = bufp;
conn->async.port = port;
conn->async.done = FALSE; /* not done */
conn->async.status = 0; /* clear */
conn->async.dns = NULL; /* clear */
ares_gethostbyname(data->state.areschannel, hostname, PF_INET,
host_callback, conn);
*waitp = TRUE; /* please wait for the response */
}
else
ares_destroy(data->state.areschannel);
}
return NULL; /* no struct yet */
}
#else
/* For builds without ARES, Curl_resolv() can never return wait==TRUE,
so this function will never be called. If it still gets called, we
return failure at once. */
CURLcode Curl_wait_for_resolv(struct connectdata *conn,
struct Curl_dns_entry **entry)
{
(void)conn;
*entry=NULL;
return CURLE_COULDNT_RESOLVE_HOST;
}
#endif
#if defined(ENABLE_IPV6) && !defined(USE_ARES)
#ifdef CURLDEBUG
/* These two are strictly for memory tracing and are using the same
@@ -377,15 +612,16 @@ void curl_freeaddrinfo(struct addrinfo *freethis,
* memory we need to free after use. That meory *MUST* be freed with
* Curl_freeaddrinfo(), nothing else.
*/
static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
static Curl_addrinfo *my_getaddrinfo(struct connectdata *conn,
char *hostname,
int port,
char **bufp)
int *waitp)
{
struct addrinfo hints, *res;
int error;
char sbuf[NI_MAXSERV];
int s, pf = PF_UNSPEC;
struct SessionHandle *data = conn->data;
/* see if we have an IPv6 stack */
s = socket(PF_INET6, SOCK_DGRAM, 0);
@@ -410,20 +646,18 @@ static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
infof(data, "getaddrinfo(3) failed for %s:%d\n", hostname, port);
return NULL;
}
*bufp=(char *)res; /* make it point to the result struct */
*waitp=0; /* don't wait, we have the response now */
return res;
}
#else /* following code is IPv4-only */
#ifndef HAVE_GETHOSTBYNAME_R
#if !defined(HAVE_GETHOSTBYNAME_R) || defined(USE_ARES)
static void hostcache_fixoffset(struct hostent *h, int offset);
/**
/*
* 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;
@@ -512,6 +746,25 @@ static struct hostent* pack_hostent(char** buf, struct hostent* orig)
}
#endif
static void hostcache_fixoffset(struct hostent *h, int offset)
{
int i=0;
h->h_name=(char *)((long)h->h_name+offset);
h->h_aliases=(char **)((long)h->h_aliases+offset);
while(h->h_aliases[i]) {
h->h_aliases[i]=(char *)((long)h->h_aliases[i]+offset);
i++;
}
h->h_addr_list=(char **)((long)h->h_addr_list+offset);
i=0;
while(h->h_addr_list[i]) {
h->h_addr_list[i]=(char *)((long)h->h_addr_list[i]+offset);
i++;
}
}
#ifndef USE_ARES
static char *MakeIP(unsigned long num, char *addr, int addr_len)
{
#if defined(HAVE_INET_NTOA) || defined(HAVE_INET_NTOA_R)
@@ -533,43 +786,24 @@ static char *MakeIP(unsigned long num, char *addr, int addr_len)
return (addr);
}
static void hostcache_fixoffset(struct hostent *h, int offset)
{
int i=0;
h->h_name=(char *)((long)h->h_name+offset);
h->h_aliases=(char **)((long)h->h_aliases+offset);
while(h->h_aliases[i]) {
h->h_aliases[i]=(char *)((long)h->h_aliases[i]+offset);
i++;
}
h->h_addr_list=(char **)((long)h->h_addr_list+offset);
i=0;
while(h->h_addr_list[i]) {
h->h_addr_list[i]=(char *)((long)h->h_addr_list[i]+offset);
i++;
}
}
/* 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. */
static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
static Curl_addrinfo *my_getaddrinfo(struct connectdata *conn,
char *hostname,
int port,
char **bufp)
int *waitp)
{
struct hostent *h = NULL;
in_addr_t in;
int ret; /* this variable is unused on several platforms but used on some */
struct SessionHandle *data = conn->data;
#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 */
(void)port; /* unused in IPv4 code */
ret = 0; /* to prevent the compiler warning */
*waitp = 0; /* don't wait, we act synchronously */
in=inet_addr(hostname);
if (in != CURL_INADDR_NONE) {
struct in_addr *addrentry;
@@ -581,7 +815,6 @@ static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
} *buf = (struct namebuf *)malloc(sizeof(struct namebuf));
if(!buf)
return NULL; /* major failure */
*bufp = (char *)buf;
h = &buf->hostentry;
h->h_addr_list = &buf->h_addr_list[0];
@@ -602,7 +835,6 @@ static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
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. */
@@ -638,7 +870,6 @@ static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
offset=(long)h-(long)buf;
hostcache_fixoffset(h, offset);
buf=(int *)h;
*bufp=(char *)buf;
}
else
#endif
@@ -687,7 +918,6 @@ static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
offset=(long)h-(long)buf;
hostcache_fixoffset(h, offset);
buf=(int *)h;
*bufp=(char *)buf;
}
else
#endif
@@ -730,13 +960,11 @@ static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
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
{
@@ -745,7 +973,6 @@ static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
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
}
@@ -753,3 +980,5 @@ static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data,
}
#endif /* end of IPv4-specific code */
#endif /* end of !USE_ARES */