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#include "stx.h"
#include "common.h"
/*****************************************
* Basic types definitions
*/
typedef struct _stx_dns_data {
struct in_addr *addrs;
int num_addrs;
int cur;
time_t expires;
} stx_dns_data_t;
#define MAX_HOST_ADDRS 1024
static struct in_addr addr_list[MAX_HOST_ADDRS];
stx_cache_t *_stx_dns_cache = NULL;
extern int _stx_dns_ttl;
extern int _stx_dns_getaddrlist(const char *hostname, struct in_addr *addrs,
int *num_addrs, st_utime_t timeout);
static unsigned long hash_hostname(const void *key)
{
const char *name = (const char *)key;
unsigned long hash = 0;
while (*name)
hash = (hash << 4) - hash + *name++; /* hash = hash * 15 + *name++ */
return hash;
}
static void cleanup_entry(void *key, void *data)
{
if (key)
free(key);
if (data) {
if (((stx_dns_data_t *)data)->addrs)
free(((stx_dns_data_t *)data)->addrs);
free(data);
}
}
static int lookup_entry(const char *host, struct in_addr *addrs,
int *num_addrs, int rotate)
{
stx_cache_entry_t *entry;
stx_dns_data_t *data;
int n;
entry = stx_cache_entry_lookup(_stx_dns_cache, host);
if (entry) {
data = (stx_dns_data_t *)stx_cache_entry_getdata(entry);
if (st_time() <= data->expires) {
if (*num_addrs == 1) {
if (rotate) {
*addrs = data->addrs[data->cur++];
if (data->cur >= data->num_addrs)
data->cur = 0;
} else {
*addrs = data->addrs[0];
}
} else {
n = STX_MIN(*num_addrs, data->num_addrs);
memcpy(addrs, data->addrs, n * sizeof(*addrs));
*num_addrs = n;
}
stx_cache_entry_release(_stx_dns_cache, entry);
return 1;
}
/*
* Cache entry expired: decrement its refcount and purge it from cache.
*/
stx_cache_entry_release(_stx_dns_cache, entry);
stx_cache_entry_delete(_stx_dns_cache, entry);
}
return 0;
}
static void insert_entry(const char *host, struct in_addr *addrs, int count)
{
stx_cache_entry_t *entry;
stx_dns_data_t *data;
char *key;
size_t n;
if (_stx_dns_ttl > 0) {
key = strdup(host);
data = (stx_dns_data_t *)malloc(sizeof(stx_dns_data_t));
n = count * sizeof(*addrs);
if (data) {
data->addrs = (struct in_addr *)malloc(n);
if (data->addrs)
memcpy(data->addrs, addrs, n);
data->num_addrs = count;
data->cur = 0;
data->expires = st_time() + _stx_dns_ttl;
}
entry = stx_cache_entry_create(key, data, strlen(host) + 1 +
sizeof(stx_dns_data_t) + n +
stx_cache_entry_sizeof());
if (key && data && data->addrs && entry &&
stx_cache_entry_insert(_stx_dns_cache, entry) == 0) {
stx_cache_entry_release(_stx_dns_cache, entry);
return;
}
if (entry)
stx_cache_entry_delete(_stx_dns_cache, entry);
else
cleanup_entry(key, data);
}
}
int _stx_dns_cache_getaddrlist(const char *hostname, struct in_addr *addrs,
int *num_addrs, st_utime_t timeout,
int rotate)
{
char host[128];
int n, count;
if (!_stx_dns_cache)
return _stx_dns_getaddrlist(hostname, addrs, num_addrs, timeout);
for (n = 0; n < sizeof(host) - 1 && hostname[n]; n++) {
host[n] = tolower(hostname[n]);
}
host[n] = '\0';
if (lookup_entry(host, addrs, num_addrs, rotate))
return 0;
count = MAX_HOST_ADDRS;
if (_stx_dns_getaddrlist(host, addr_list, &count, timeout) < 0)
return -1;
n = STX_MIN(*num_addrs, count);
memcpy(addrs, addr_list, n * sizeof(*addrs));
*num_addrs = n;
insert_entry(host, addr_list, count);
return 0;
}
int stx_dns_cache_init(size_t max_size, size_t max_bytes, size_t hash_size)
{
_stx_dns_cache = stx_cache_create(max_size, max_bytes, hash_size,
hash_hostname,
(long (*)(const void *, const void *))strcmp,
cleanup_entry);
if (!_stx_dns_cache)
return -1;
return 0;
}
void stx_dns_cache_getinfo(stx_cache_info_t *info)
{
if (_stx_dns_cache)
stx_cache_getinfo(_stx_dns_cache, info);
else
memset(info, 0, sizeof(stx_cache_info_t));
}
int stx_dns_getaddrlist(const char *hostname, struct in_addr *addrs,
int *num_addrs, st_utime_t timeout)
{
return _stx_dns_cache_getaddrlist(hostname, addrs, num_addrs, timeout, 0);
}
int stx_dns_getaddr(const char *hostname, struct in_addr *addr,
st_utime_t timeout)
{
int n = 1;
return _stx_dns_cache_getaddrlist(hostname, addr, &n, timeout, 1);
}
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