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dns_cache.c
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dns_cache.c
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/*
* resolver related functions
*
* Copyright (C) 2006 iptelorg GmbH
*
* This file is part of Kamailio, a free SIP server.
*
* Kamailio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version
*
* Kamailio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*!
* \file
* \brief Kamailio core :: DNS cache handling
* \ingroup core
* Module: \ref core
*/
#ifdef USE_DNS_CACHE
#ifdef DNS_SRV_LB
#include <stdlib.h> /* FIXME: rand() */
#endif
#include <string.h>
#include "globals.h"
#include "cfg_core.h"
#include "dns_cache.h"
#include "dns_wrappers.h"
#include "compiler_opt.h"
#include "mem/shm_mem.h"
#include "hashes.h"
#include "clist.h"
#include "locking.h"
#include "atomic_ops.h"
#include "ut.h"
#include "timer.h"
#include "timer_ticks.h"
#include "error.h"
#include "rpc.h"
#include "rand/fastrand.h"
#ifdef USE_DNS_CACHE_STATS
#include "pt.h"
#endif
#define DNS_CACHE_DEBUG /* extra sanity checks and debugging */
#ifndef MAX
#define MAX(a,b) ( ((a)>(b))?(a):(b))
#endif
#define MAX_DNS_RECORDS 255 /* maximum dns records number received in a
dns answer*/
#define DNS_HASH_SIZE 1024 /* must be <= 65535 */
#define DEFAULT_DNS_TIMER_INTERVAL 120 /* 2 min. */
#define DNS_HE_MAX_ADDR 10 /* maxium addresses returne in a hostent struct */
#define MAX_CNAME_CHAIN 10
#define SPACE_FORMAT " " /* format of view output */
#define DNS_SRV_ZERO_W_CHANCE 1000 /* one in a 1000*weight_sum chance for
selecting a 0-weight record */
int dns_cache_init=1; /* if 0, the DNS cache is not initialized at startup */
static gen_lock_t* dns_hash_lock=0;
static volatile unsigned int *dns_cache_mem_used=0; /* current mem. use */
unsigned int dns_timer_interval=DEFAULT_DNS_TIMER_INTERVAL; /* in s */
int dns_flags=0; /* default flags used for the dns_*resolvehost
(compatibility wrappers) */
#ifdef USE_DNS_CACHE_STATS
struct t_dns_cache_stats* dns_cache_stats=0;
#endif
#define LOCK_DNS_HASH() lock_get(dns_hash_lock)
#define UNLOCK_DNS_HASH() lock_release(dns_hash_lock)
#define FIX_TTL(t) \
(((t)<cfg_get(core, core_cfg, dns_cache_min_ttl))? \
cfg_get(core, core_cfg, dns_cache_min_ttl): \
(((t)>cfg_get(core, core_cfg, dns_cache_max_ttl))? \
cfg_get(core, core_cfg, dns_cache_max_ttl): \
(t)))
struct dns_hash_head{
struct dns_hash_entry* next;
struct dns_hash_entry* prev;
};
#ifdef DNS_LU_LST
struct dns_lu_lst* dns_last_used_lst=0;
#endif
static struct dns_hash_head* dns_hash=0;
static struct timer_ln* dns_timer_h=0;
#ifdef DNS_WATCHDOG_SUPPORT
static atomic_t *dns_servers_up = NULL;
#endif
static const char* dns_str_errors[]={
"no error",
"no more records", /* not an error, but and end condition */
"unknown error",
"internal error",
"bad SRV entry",
"unresolvable SRV request",
"bad A or AAAA entry",
"unresolvable A or AAAA request",
"invalid ip in A or AAAA record",
"blacklisted ip",
"name too long ", /* try again with a shorter name */
"ip AF mismatch", /* address family mismatch */
"unresolvable NAPTR request",
"bug - critical error"
};
/* param: err (negative error number) */
const char* dns_strerror(int err)
{
err=-err;
if ((err>=0) && (err<sizeof(dns_str_errors)/sizeof(char*)))
return dns_str_errors[err];
return "bug -- bad error number";
}
/* "internal" only, don't use unless you really know waht you're doing */
inline static void dns_destroy_entry(struct dns_hash_entry* e)
{
#ifdef DNS_CACHE_DEBUG
memset(e, 0, e->total_size);
#endif
shm_free(e); /* nice having it in one block isn't it? :-) */
}
/* "internal" only, same as above, asumes shm_lock() held (tm optimization) */
inline static void dns_destroy_entry_shm_unsafe(struct dns_hash_entry* e)
{
#ifdef DNS_CACHE_DEBUG
memset(e, 0, e->total_size);
#endif
shm_free_unsafe(e); /* nice having it in one block isn't it? :-) */
}
/* dec. the internal refcnt and if 0 deletes the entry */
void dns_hash_put(struct dns_hash_entry* e)
{
if(e && atomic_dec_and_test(&e->refcnt)){
/* atomic_sub_long(dns_cache_total_used, e->total_size); */
dns_destroy_entry(e);
}
}
/* same as above but uses dns_destroy_unsafe (assumes shm_lock held -- tm
* optimization) */
void dns_hash_put_shm_unsafe(struct dns_hash_entry* e)
{
if(e && atomic_dec_and_test(&e->refcnt)){
/* atomic_sub_long(dns_cache_total_used, e->total_size); */
dns_destroy_entry_shm_unsafe(e);
}
}
inline static int dns_cache_clean(unsigned int no, int expired_only);
inline static int dns_cache_free_mem(unsigned int target, int expired_only);
static ticks_t dns_timer(ticks_t ticks, struct timer_ln* tl, void* data)
{
#ifdef DNS_WATCHDOG_SUPPORT
/* do not clean the hash table if the servers are down */
if (atomic_get(dns_servers_up) == 0)
return (ticks_t)(-1);
#endif
if (*dns_cache_mem_used>12*(cfg_get(core, core_cfg, dns_cache_max_mem)/16)){ /* ~ 75% used */
dns_cache_free_mem(cfg_get(core, core_cfg, dns_cache_max_mem)/2, 1);
}else{
dns_cache_clean(-1, 1); /* all the table, only expired entries */
/* TODO: better strategy? */
}
return (ticks_t)(-1);
}
void destroy_dns_cache()
{
if (dns_timer_h){
timer_del(dns_timer_h);
timer_free(dns_timer_h);
dns_timer_h=0;
}
#ifdef DNS_WATCHDOG_SUPPORT
if (dns_servers_up){
shm_free(dns_servers_up);
dns_servers_up=0;
}
#endif
if (dns_hash_lock){
lock_destroy(dns_hash_lock);
lock_dealloc(dns_hash_lock);
dns_hash_lock=0;
}
if (dns_hash){
shm_free(dns_hash);
dns_hash=0;
}
#ifdef DNS_LU_LST
if (dns_last_used_lst){
shm_free(dns_last_used_lst);
dns_last_used_lst=0;
}
#endif
#ifdef USE_DNS_CACHE_STATS
if (dns_cache_stats)
shm_free(dns_cache_stats);
#endif
if (dns_cache_mem_used){
shm_free((void*)dns_cache_mem_used);
dns_cache_mem_used=0;
}
}
/* set the value of dns_flags */
void fix_dns_flags(str *gname, str *name)
{
/* restore the original value of dns_cache_flags first
* (DNS_IPV4_ONLY may have been set only because dns_try_ipv6
* was disabled, and the flag must be cleared when
* dns_try_ipv6 is enabled) (Miklos)
*/
dns_flags = cfg_get(core, core_cfg, dns_cache_flags) & 7;
if (cfg_get(core, core_cfg, dns_try_ipv6)==0){
dns_flags|=DNS_IPV4_ONLY;
}
if (dns_flags & DNS_IPV4_ONLY){
dns_flags&=~(DNS_IPV6_ONLY|DNS_IPV6_FIRST);
}
if (cfg_get(core, core_cfg, dns_srv_lb)){
#ifdef DNS_SRV_LB
dns_flags|=DNS_SRV_RR_LB;
#else
LM_WARN("SRV loadbalaning is set, but"
" support for it is not compiled -- ignoring\n");
#endif
}
if (cfg_get(core, core_cfg, dns_try_naptr)) {
#ifndef USE_NAPTR
LM_WARN("NAPTR support is enabled, but"
" support for it is not compiled -- ignoring\n");
#endif
dns_flags|=DNS_TRY_NAPTR;
}
}
/* fixup function for use_dns_failover
* verifies that use_dns_cache is set to 1
*/
int use_dns_failover_fixup(void *handle, str *gname, str *name, void **val)
{
if ((int)(long)(*val) && !cfg_get(core, handle, use_dns_cache)) {
LM_ERR("DNS cache is turned off, failover cannot be enabled. "
"(set use_dns_cache to 1)\n");
return -1;
}
return 0;
}
/* fixup function for use_dns_cache
* verifies that dns_cache_init is set to 1
*/
int use_dns_cache_fixup(void *handle, str *gname, str *name, void **val)
{
if ((int)(long)(*val) && !dns_cache_init) {
LM_ERR("DNS cache is turned off by dns_cache_init=0, "
"it cannot be enabled runtime.\n");
return -1;
}
if (((int)(long)(*val)==0) && cfg_get(core, handle, use_dns_failover)) {
LM_ERR("DNS failover depends on use_dns_cache, set use_dns_failover "
"to 0 before disabling the DNS cache\n");
return -1;
}
return 0;
}
/* KByte to Byte conversion */
int dns_cache_max_mem_fixup(void *handle, str *gname, str *name, void **val)
{
unsigned int u;
u = ((unsigned int)(long)(*val))<<10;
(*val) = (void *)(long)u;
return 0;
}
int init_dns_cache()
{
int r;
int ret;
if (dns_cache_init==0) {
/* the DNS cache is turned off */
default_core_cfg.use_dns_cache=0;
default_core_cfg.use_dns_failover=0;
return 0;
}
ret=0;
/* sanity check */
if (E_DNS_CRITICAL>=sizeof(dns_str_errors)/sizeof(char*)){
LM_CRIT("bad dns error table\n");
ret=E_BUG;
goto error;
}
dns_cache_mem_used=shm_malloc(sizeof(*dns_cache_mem_used));
if (dns_cache_mem_used==0){
ret=E_OUT_OF_MEM;
goto error;
}
#ifdef DNS_LU_LST
dns_last_used_lst=shm_malloc(sizeof(*dns_last_used_lst));
if (dns_last_used_lst==0){
ret=E_OUT_OF_MEM;
goto error;
}
clist_init(dns_last_used_lst, next, prev);
#endif
dns_hash=shm_malloc(sizeof(struct dns_hash_head)*DNS_HASH_SIZE);
if (dns_hash==0){
ret=E_OUT_OF_MEM;
goto error;
}
for (r=0; r<DNS_HASH_SIZE; r++)
clist_init(&dns_hash[r], next, prev);
dns_hash_lock=lock_alloc();
if (dns_hash_lock==0){
ret=E_OUT_OF_MEM;
goto error;
}
if (lock_init(dns_hash_lock)==0){
lock_dealloc(dns_hash_lock);
dns_hash_lock=0;
ret=-1;
goto error;
}
#ifdef DNS_WATCHDOG_SUPPORT
dns_servers_up=shm_malloc(sizeof(atomic_t));
if (dns_servers_up==0){
ret=E_OUT_OF_MEM;
goto error;
}
atomic_set(dns_servers_up, 1);
#endif
/* fix options */
default_core_cfg.dns_cache_max_mem<<=10; /* Kb */ /* TODO: test with 0 */
if (default_core_cfg.use_dns_cache==0)
default_core_cfg.use_dns_failover=0; /* cannot work w/o dns_cache support */
/* fix flags */
fix_dns_flags(NULL, NULL);
dns_timer_h=timer_alloc();
if (dns_timer_h==0){
ret=E_OUT_OF_MEM;
goto error;
}
if (dns_timer_interval){
timer_init(dns_timer_h, dns_timer, 0, 0); /* "slow" timer */
if (timer_add(dns_timer_h, S_TO_TICKS(dns_timer_interval))<0){
LM_CRIT("failed to add the timer\n");
timer_free(dns_timer_h);
dns_timer_h=0;
goto error;
}
}
return 0;
error:
destroy_dns_cache();
return ret;
}
#ifdef USE_DNS_CACHE_STATS
int init_dns_cache_stats(int iproc_num)
{
/* do not initialize the stats array if the DNS cache will not be used */
if (dns_cache_init==0) return 0;
/* if it is already initialized */
if (dns_cache_stats)
shm_free(dns_cache_stats);
dns_cache_stats=shm_malloc(sizeof(*dns_cache_stats) * iproc_num);
if (dns_cache_stats==0){
return E_OUT_OF_MEM;
}
memset(dns_cache_stats, 0, sizeof(*dns_cache_stats) * iproc_num);
return 0;
}
#endif
/* hash function, type is not used (obsolete)
* params: char* s, int len, int type
* returns the hash value
*/
#define dns_hash_no(s, len, type) \
(get_hash1_case_raw((s),(len)) % DNS_HASH_SIZE)
#ifdef DNS_CACHE_DEBUG
#define DEBUG_LU_LST
#ifdef DEBUG_LU_LST
#include <stdlib.h> /* abort() */
#define check_lu_lst(l) ((((l)->next==(l)) || ((l)->prev==(l))) && \
((l)!=dns_last_used_lst))
#define dbg_lu_lst(txt, l) \
LM_CRIT("%s: crt(%p, %p, %p)," \
" prev(%p, %p, %p), next(%p, %p, %p)\n", txt, \
(l), (l)->next, (l)->prev, \
(l)->prev, (l)->prev->next, (l)->prev->prev, \
(l)->next, (l)->next->next, (l)->next->prev \
)
#define debug_lu_lst( txt, l) \
do{ \
if (check_lu_lst((l))){ \
dbg_lu_lst(txt " crt:", (l)); \
abort(); \
} \
if (check_lu_lst((l)->next)){ \
dbg_lu_lst(txt " next:", (l)); \
abort(); \
} \
if (check_lu_lst((l)->prev)){ \
dbg_lu_lst(txt " prev:", (l)); \
abort(); \
} \
}while(0)
#endif
#endif /* DNS_CACHE_DEBUG */
/* must be called with the DNS_LOCK hold
* remove and entry from the hash, dec. its refcnt and if not referenced
* anymore deletes it */
inline static void _dns_hash_remove(struct dns_hash_entry* e)
{
clist_rm(e, next, prev);
#ifdef DNS_CACHE_DEBUG
e->next=e->prev=0;
#endif
#ifdef DNS_LU_LST
#ifdef DEBUG_LU_LST
debug_lu_lst("_dns_hash_remove: pre rm:", &e->last_used_lst);
#endif
clist_rm(&e->last_used_lst, next, prev);
#ifdef DEBUG_LU_LST
debug_lu_lst("_dns_hash_remove: post rm:", &e->last_used_lst);
#endif
#ifdef DNS_CACHE_DEBUG
e->last_used_lst.next=e->last_used_lst.prev=0;
#endif
#endif
*dns_cache_mem_used-=e->total_size;
dns_hash_put(e);
}
/* non locking version (the dns hash must _be_ locked externally)
* returns 0 when not found, or the entry on success (an entry with a
* similar name but with a CNAME type will always match).
* it doesn't increase the internal refcnt
* returns the entry when found, 0 when not found and sets *err to !=0
* on error (e.g. recursive cnames)
* WARNING: - internal use only
* - always check if the returned entry type is CNAME */
inline static struct dns_hash_entry* _dns_hash_find(str* name, int type,
int* h, int* err)
{
struct dns_hash_entry* e;
struct dns_hash_entry* tmp;
struct dns_hash_entry* ret;
ticks_t now;
int cname_chain;
str cname;
#ifdef DNS_WATCHDOG_SUPPORT
int servers_up;
servers_up = atomic_get(dns_servers_up);
#endif
cname_chain=0;
ret=0;
now=get_ticks_raw();
*err=0;
again:
*h=dns_hash_no(name->s, name->len, type);
#ifdef DNS_CACHE_DEBUG
DBG("dns_hash_find(%.*s(%d), %d), h=%d\n", name->len, name->s,
name->len, type, *h);
#endif
clist_foreach_safe(&dns_hash[*h], e, tmp, next){
if (
#ifdef DNS_WATCHDOG_SUPPORT
/* remove expired elements only when the dns servers are up */
servers_up &&
#endif
/* automatically remove expired elements */
((e->ent_flags & DNS_FLAG_PERMANENT) == 0) &&
((s_ticks_t)(now-e->expire)>=0)
) {
_dns_hash_remove(e);
}else if ((e->type==type) && (e->name_len==name->len) &&
(strncasecmp(e->name, name->s, e->name_len)==0)){
e->last_used=now;
#ifdef DNS_LU_LST
/* add it at the end */
#ifdef DEBUG_LU_LST
debug_lu_lst("_dns_hash_find: pre rm:", &e->last_used_lst);
#endif
clist_rm(&e->last_used_lst, next, prev);
clist_append(dns_last_used_lst, &e->last_used_lst, next, prev);
#ifdef DEBUG_LU_LST
debug_lu_lst("_dns_hash_find: post append:", &e->last_used_lst);
#endif
#endif
return e;
}else if ((e->type==T_CNAME) &&
!((e->rr_lst==0) || (e->ent_flags & DNS_FLAG_BAD_NAME)) &&
(e->name_len==name->len) &&
(strncasecmp(e->name, name->s, e->name_len)==0)){
/*if CNAME matches and CNAME is entry is not a neg. cache entry
(could be produced by a specific CNAME lookup)*/
e->last_used=now;
#ifdef DNS_LU_LST
/* add it at the end */
#ifdef DEBUG_LU_LST
debug_lu_lst("_dns_hash_find: cname: pre rm:", &e->last_used_lst);
#endif
clist_rm(&e->last_used_lst, next, prev);
clist_append(dns_last_used_lst, &e->last_used_lst, next, prev);
#ifdef DEBUG_LU_LST
debug_lu_lst("_dns_hash_find: cname: post append:",
&e->last_used_lst);
#endif
#endif
ret=e; /* if this is an unfinished cname chain, we try to
return the last cname */
/* this is a cname => retry using its value */
if (cname_chain> MAX_CNAME_CHAIN){
LM_ERR("cname chain too long or recursive (\"%.*s\")\n",
name->len, name->s);
ret=0; /* error*/
*err=-1;
break;
}
cname_chain++;
cname.s=((struct cname_rdata*)e->rr_lst->rdata)->name;
cname.len= ((struct cname_rdata*)e->rr_lst->rdata)->name_len;
name=&cname;
goto again;
}
}
return ret;
}
/* frees cache entries, if expired_only=0 only expired entries will be
* removed, else all of them
* it will process maximum no entries (to process all of them use -1)
* returns the number of deleted entries
* This should be called from a timer process*/
inline static int dns_cache_clean(unsigned int no, int expired_only)
{
struct dns_hash_entry* e;
ticks_t now;
unsigned int n;
unsigned int deleted;
#ifdef DNS_LU_LST
struct dns_lu_lst* l;
struct dns_lu_lst* tmp;
#else
struct dns_hash_entry* t;
unsigned int h;
static unsigned int start=0;
#endif
n=0;
deleted=0;
now=get_ticks_raw();
LOCK_DNS_HASH();
#ifdef DNS_LU_LST
clist_foreach_safe(dns_last_used_lst, l, tmp, next){
e=(struct dns_hash_entry*)(((char*)l)-
(char*)&((struct dns_hash_entry*)(0))->last_used_lst);
if (((e->ent_flags & DNS_FLAG_PERMANENT) == 0)
&& (!expired_only || ((s_ticks_t)(now-e->expire)>=0))
) {
_dns_hash_remove(e);
deleted++;
}
n++;
if (n>=no) break;
}
#else
for(h=start; h!=(start+DNS_HASH_SIZE); h++){
clist_foreach_safe(&dns_hash[h%DNS_HASH_SIZE], e, t, next){
if (((e->ent_flags & DNS_FLAG_PERMANENT) == 0)
&& ((s_ticks_t)(now-e->expire)>=0)
) {
_dns_hash_remove(e);
deleted++;
}
n++;
if (n>=no) goto skip;
}
}
/* not fair, but faster then random() */
if (!expired_only){
for(h=start; h!=(start+DNS_HASH_SIZE); h++){
clist_foreach_safe(&dns_hash[h%DNS_HASH_SIZE], e, t, next){
if ((e->ent_flags & DNS_FLAG_PERMANENT) == 0) {
_dns_hash_remove(e);
deleted++;
}
n++;
if (n>=no) goto skip;
}
}
}
skip:
start=h;
#endif
UNLOCK_DNS_HASH();
return deleted;
}
/* frees cache entries, if expired_only=0 only expired entries will be
* removed, else all of them
* it will stop when the dns cache used memory reaches target (to process all
* of them use 0)
* returns the number of deleted entries */
inline static int dns_cache_free_mem(unsigned int target, int expired_only)
{
struct dns_hash_entry* e;
ticks_t now;
unsigned int deleted;
#ifdef DNS_LU_LST
struct dns_lu_lst* l;
struct dns_lu_lst* tmp;
#else
struct dns_hash_entry* t;
unsigned int h;
static unsigned int start=0;
#endif
deleted=0;
now=get_ticks_raw();
LOCK_DNS_HASH();
#ifdef DNS_LU_LST
clist_foreach_safe(dns_last_used_lst, l, tmp, next){
if (*dns_cache_mem_used<=target) break;
e=(struct dns_hash_entry*)(((char*)l)-
(char*)&((struct dns_hash_entry*)(0))->last_used_lst);
if (((e->ent_flags & DNS_FLAG_PERMANENT) == 0)
&& (!expired_only || ((s_ticks_t)(now-e->expire)>=0))
) {
_dns_hash_remove(e);
deleted++;
}
}
#else
for(h=start; h!=(start+DNS_HASH_SIZE); h++){
clist_foreach_safe(&dns_hash[h%DNS_HASH_SIZE], e, t, next){
if (*dns_cache_mem_used<=target)
goto skip;
if (((e->ent_flags & DNS_FLAG_PERMANENT) == 0)
&& ((s_ticks_t)(now-e->expire)>=0)
) {
_dns_hash_remove(e);
deleted++;
}
}
}
/* not fair, but faster then random() */
if (!expired_only){
for(h=start; h!=(start+DNS_HASH_SIZE); h++){
clist_foreach_safe(&dns_hash[h%DNS_HASH_SIZE], e, t, next){
if (*dns_cache_mem_used<=target)
goto skip;
if (((e->ent_flags & DNS_FLAG_PERMANENT) == 0)
&& ((s_ticks_t)(now-e->expire)>=0)
) {
_dns_hash_remove(e);
deleted++;
}
}
}
}
skip:
start=h;
#endif
UNLOCK_DNS_HASH();
return deleted;
}
/* locking version (the dns hash must _not_be locked externally)
* returns 0 when not found, the searched entry on success (with CNAMEs
* followed) or the last CNAME entry from an unfinished CNAME chain,
* if the search matches a CNAME. On error sets *err (e.g. recursive CNAMEs).
* it increases the internal refcnt => when finished dns_hash_put() must
* be called on the returned entry
* WARNING: - the return might be a CNAME even if type!=CNAME, see above */
inline static struct dns_hash_entry* dns_hash_get(str* name, int type, int* h,
int* err)
{
struct dns_hash_entry* e;
LOCK_DNS_HASH();
e=_dns_hash_find(name, type, h, err);
if (e){
atomic_inc(&e->refcnt);
}
UNLOCK_DNS_HASH();
return e;
}
/* adds a fully created and init. entry (see dns_cache_mk_entry()) to the hash
* table
* returns 0 on success, -1 on error */
inline static int dns_cache_add(struct dns_hash_entry* e)
{
int h;
/* check space */
/* atomic_add_long(dns_cache_total_used, e->size); */
if ((*dns_cache_mem_used+e->total_size)>=cfg_get(core, core_cfg, dns_cache_max_mem)){
#ifdef USE_DNS_CACHE_STATS
dns_cache_stats[process_no].dc_lru_cnt++;
#endif
LM_WARN("cache full, trying to free...\n");
/* free ~ 12% of the cache */
dns_cache_free_mem(*dns_cache_mem_used/16*14,
!cfg_get(core, core_cfg, dns_cache_del_nonexp));
if ((*dns_cache_mem_used+e->total_size)>=cfg_get(core, core_cfg, dns_cache_max_mem)){
LM_ERR("max. cache mem size exceeded\n");
return -1;
}
}
atomic_inc(&e->refcnt);
h=dns_hash_no(e->name, e->name_len, e->type);
#ifdef DNS_CACHE_DEBUG
DBG("dns_cache_add: adding %.*s(%d) %d (flags=%0x) at %d\n",
e->name_len, e->name, e->name_len, e->type, e->ent_flags, h);
#endif
LOCK_DNS_HASH();
*dns_cache_mem_used+=e->total_size; /* no need for atomic ops, written
only from within a lock */
clist_append(&dns_hash[h], e, next, prev);
#ifdef DNS_LU_LST
clist_append(dns_last_used_lst, &e->last_used_lst, next, prev);
#endif
UNLOCK_DNS_HASH();
return 0;
}
/* same as above, but it must be called with the dns hash lock held
* returns 0 on success, -1 on error */
inline static int dns_cache_add_unsafe(struct dns_hash_entry* e)
{
int h;
/* check space */
/* atomic_add_long(dns_cache_total_used, e->size); */
if ((*dns_cache_mem_used+e->total_size)>=cfg_get(core, core_cfg, dns_cache_max_mem)){
#ifdef USE_DNS_CACHE_STATS
dns_cache_stats[process_no].dc_lru_cnt++;
#endif
LM_WARN("cache full, trying to free...\n");
/* free ~ 12% of the cache */
UNLOCK_DNS_HASH();
dns_cache_free_mem(*dns_cache_mem_used/16*14,
!cfg_get(core, core_cfg, dns_cache_del_nonexp));
LOCK_DNS_HASH();
if ((*dns_cache_mem_used+e->total_size)>=cfg_get(core, core_cfg, dns_cache_max_mem)){
LM_ERR("max. cache mem size exceeded\n");
return -1;
}
}
atomic_inc(&e->refcnt);
h=dns_hash_no(e->name, e->name_len, e->type);
#ifdef DNS_CACHE_DEBUG
DBG("dns_cache_add: adding %.*s(%d) %d (flags=%0x) at %d\n",
e->name_len, e->name, e->name_len, e->type, e->ent_flags, h);
#endif
*dns_cache_mem_used+=e->total_size; /* no need for atomic ops, written
only from within a lock */
clist_append(&dns_hash[h], e, next, prev);
#ifdef DNS_LU_LST
clist_append(dns_last_used_lst, &e->last_used_lst, next, prev);
#endif
return 0;
}
/* creates a "negative" entry which will be valid for ttl seconds */
inline static struct dns_hash_entry* dns_cache_mk_bad_entry(str* name,
int type,
int ttl,
int flags)
{
struct dns_hash_entry* e;
int size;
ticks_t now;
#ifdef DNS_CACHE_DEBUG
DBG("dns_cache_mk_bad_entry(%.*s, %d, %d, %d)\n", name->len, name->s,
type, ttl, flags);
#endif
size=sizeof(struct dns_hash_entry)+name->len-1+1;
e=shm_malloc(size);
if (e==0){
LM_ERR("out of memory\n");
return 0;
}
memset(e, 0, size); /* init with 0*/
e->total_size=size;
e->name_len=name->len;
e->type=type;
now=get_ticks_raw();
e->last_used=now;
e->expire=now+S_TO_TICKS(ttl);
memcpy(e->name, name->s, name->len);
e->ent_flags=flags;
return e;
}
/* create a a/aaaa hash entry from a name and ip address
* returns 0 on error */
inline static struct dns_hash_entry* dns_cache_mk_ip_entry(str* name,
struct ip_addr* ip)
{
struct dns_hash_entry* e;
int size;
ticks_t now;
/* everything is allocated in one block: dns_hash_entry + name +
* + dns_rr + rdata; dns_rr must start at an aligned adress,
* hence we need to round dns_hash_entry+name size to a sizeof(long)
* multiple.
* Memory image:
* struct dns_hash_entry
* name (name_len+1 bytes)
* padding to multiple of sizeof(long)
* dns_rr
* rdata (no padding needed, since for ip is just an array of chars)
*/
size=ROUND_POINTER(sizeof(struct dns_hash_entry)+name->len-1+1)+
sizeof(struct dns_rr)+ ip->len;
e=shm_malloc(size);
if (e==0){
LM_ERR("out of memory\n");
return 0;
}
memset(e, 0, size); /* init with 0*/
e->total_size=size;
e->name_len=name->len;
e->type=(ip->af==AF_INET)?T_A:T_AAAA;
now=get_ticks_raw();
e->last_used=now;
e->expire=now-1; /* maximum expire */
memcpy(e->name, name->s, name->len); /* memset makes sure is 0-term. */
e->rr_lst=(void*)((char*)e+
ROUND_POINTER(sizeof(struct dns_hash_entry)+name->len-1+1));
e->rr_lst->rdata=(void*)((char*)e->rr_lst+sizeof(struct dns_rr));
e->rr_lst->expire=now-1; /* maximum expire */
/* no need to align rr_lst->rdata for a or aaaa records */
memcpy(e->rr_lst->rdata, ip->u.addr, ip->len);
return e;
}
/* creates an srv hash entry from the given parameters
* returns 0 on error */
static struct dns_hash_entry* dns_cache_mk_srv_entry(str* name,
unsigned short priority,
unsigned short weight,
unsigned short port,
str* rr_name,
int ttl)
{
struct dns_hash_entry* e;
int size;
ticks_t now;
/* everything is allocated in one block: dns_hash_entry + name +
* + dns_rr + rdata; dns_rr must start at an aligned adress,
* hence we need to round dns_hash_entry+name size to a sizeof(long),
* and similarly, dns_rr must be rounded to sizeof(short).
* multiple.
* Memory image:
* struct dns_hash_entry
* name (name_len+1 bytes)
* padding to multiple of sizeof(long)
* dns_rr
* padding to multiple of sizeof(short)
* rdata
*/
size=ROUND_POINTER(sizeof(struct dns_hash_entry)+name->len-1+1) +
ROUND_SHORT(sizeof(struct dns_rr)) +
sizeof(struct srv_rdata)-1 +
rr_name->len+1;
e=shm_malloc(size);
if (e==0){
LM_ERR("out of memory\n");
return 0;
}
memset(e, 0, size); /* init with 0*/
e->total_size=size;
e->name_len=name->len;
e->type=T_SRV;
now=get_ticks_raw();
e->last_used=now;
e->expire=now+S_TO_TICKS(ttl);
memcpy(e->name, name->s, name->len); /* memset makes sure is 0-term. */
e->rr_lst=(void*)((char*)e+
ROUND_POINTER(sizeof(struct dns_hash_entry)+name->len-1+1));
e->rr_lst->rdata=(void*)((char*)e->rr_lst+ROUND_SHORT(sizeof(struct dns_rr)));
e->rr_lst->expire=e->expire;
((struct srv_rdata*)e->rr_lst->rdata)->priority = priority;
((struct srv_rdata*)e->rr_lst->rdata)->weight = weight;
((struct srv_rdata*)e->rr_lst->rdata)->port = port;
((struct srv_rdata*)e->rr_lst->rdata)->name_len = rr_name->len;
memcpy(((struct srv_rdata*)e->rr_lst->rdata)->name, rr_name->s, rr_name->len);
return e;
}
/* create a dns hash entry from a name and a rdata list (pkg_malloc'ed)
* (it will use only the type records with the name "name" from the
* rdata list with one exception: if a matching CNAME with the same
* name is found, the search will stop and this will be the record used)
* returns 0 on error and removes the used elements from the rdata list*/
inline static struct dns_hash_entry* dns_cache_mk_rd_entry(str* name, int type,
struct rdata** rd_lst)
{
struct dns_hash_entry* e;
struct dns_rr* rr;
struct dns_rr** tail_rr;
struct rdata** p;