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replace hostent lookup with better performing in-memory copy.

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the central dns resolver function proxy_gethostbyname() used
to iterate over the gethostent() db (/etc/hosts) on each dns
request.
since this is not threadsafe, we synchronized access to it
previously using mutexes. the parsing of this file is slow,
and blocking all threads to do it even moreso.
since gethostent_r() is only available on a few platforms,
i decided to read the hostent db once and then use a quick
in-memory lookup on further usage.

+ some further refactoring.
This commit is contained in:
rofl0r
2012-11-08 01:18:19 +01:00
parent c698d48c03
commit af5c6f0c6a
11 changed files with 208 additions and 39 deletions
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28
src/core.c
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@ -34,8 +34,6 @@
#include <sys/time.h>
#include <stdarg.h>
#include <assert.h>
#include "mutex.h"
pthread_mutex_t hostdb_lock;
#include "core.h"
#include "common.h"
@ -666,12 +664,14 @@ int connect_proxy_chain(int sock, ip_type target_ip,
return -1;
}
#include "hostentdb.h"
struct hostent_list hl;
void core_initialize(void) {
MUTEX_INIT(&hostdb_lock);
hdb_init(&hl);
}
void core_unload(void) {
MUTEX_DESTROY(&hostdb_lock);
}
static void gethostbyname_data_setstring(struct gethostbyname_data* data, char* name) {
@ -682,9 +682,6 @@ static void gethostbyname_data_setstring(struct gethostbyname_data* data, char*
struct hostent *proxy_gethostbyname(const char *name, struct gethostbyname_data* data) {
PFUNC();
char buff[256];
size_t l = strlen(name);
struct hostent *hp;
data->resolved_addr_p[0] = (char *) &data->resolved_addr;
data->resolved_addr_p[1] = NULL;
@ -709,16 +706,13 @@ struct hostent *proxy_gethostbyname(const char *name, struct gethostbyname_data*
memset(buff, 0, sizeof(buff));
// this iterates over the "known hosts" db, usually /etc/hosts
MUTEX_LOCK(&hostdb_lock);
while((hp = gethostent()))
if(!strcmp(hp->h_name, name) && hp->h_addrtype == AF_INET && hp->h_length == sizeof(in_addr_t)) {
data->resolved_addr = *((in_addr_t*)(hp->h_addr_list[0]));
MUTEX_UNLOCK(&hostdb_lock);
goto retname;
}
MUTEX_UNLOCK(&hostdb_lock);
data->resolved_addr = at_get_ip_for_host((char*) name, l).as_int;
ip_type hdb_res = hdb_get(&hl, (char*) name);
if(hdb_res.as_int != ip_type_invalid.as_int) {
data->resolved_addr = hdb_res.as_int;
goto retname;
}
data->resolved_addr = at_get_ip_for_host((char*) name, strlen(name)).as_int;
if(data->resolved_addr == (in_addr_t) ip_type_invalid.as_int) return NULL;
retname: