- use_dns_cache can be enabled/disabled runtime

- dns_cache_init is introduced: if set to 0, the dns cache is not
initialized, and cannot be enabled later (default is 1)
- dst_blacklist_init is introduced: if set to 0, the dst blacklist is
not initialized (similar to dns_cache_init) (default is 1)

diff --git a/NEWS b/NEWS
index d3efae4..5020868 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -197,6 +197,13 @@ new config variables:
   tcp_source_ipv6 = IPv6 address
     Set the given source IP for all outbound TCP connections.
     If setting the IP fails the TCP connection will use the default.
+  dns_cache_init = on | off (default on) - if off, the dns cache is not
+    initialized at startup and cannot be enabled runtime, that saves some
+    memory.
+  dst_blacklist_init = on | off (default on) - if off, the blacklist
+    is not initialized at startup and cannot be enabled runtime,
+    that saves some memory.
+
 
 
 2.0.0 changes

diff --git a/cfg.lex b/cfg.lex
index b1f90d8..4bf115f 100644 (file)
--- a/cfg.lex
+++ b/cfg.lex
@@ -250,6 +250,7 @@ DNS_SERVERS_NO      dns_servers_no
 DNS_USE_SEARCH dns_use_search_list
 DNS_SEARCH_FMATCH      dns_search_full_match
 /* dns cache */
+DNS_CACHE_INIT dns_cache_init
 DNS_USE_CACHE  use_dns_cache
 DNS_USE_FAILOVER       use_dns_failover
 DNS_CACHE_FLAGS                dns_cache_flags
@@ -260,6 +261,7 @@ DNS_CACHE_MEM               dns_cache_mem
 DNS_CACHE_GC_INT       dns_cache_gc_interval
 DNS_CACHE_DEL_NONEXP   dns_cache_del_nonexp|dns_cache_delete_nonexpired
 /* blacklist */
+DST_BLST_INIT  dst_blacklist_init
 USE_DST_BLST           use_dst_blacklist
 DST_BLST_MEM           dst_blacklist_mem
 DST_BLST_TTL           dst_blacklist_expire|dst_blacklist_ttl
@@ -506,6 +508,8 @@ EAT_ABLE    [\ \t\b\r]
                                                                return DNS_USE_SEARCH; }
 <INITIAL>{DNS_SEARCH_FMATCH}   { count(); yylval.strval=yytext;
                                                                return DNS_SEARCH_FMATCH; }
+<INITIAL>{DNS_CACHE_INIT}      { count(); yylval.strval=yytext;
+                                                               return DNS_CACHE_INIT; }
 <INITIAL>{DNS_USE_CACHE}       { count(); yylval.strval=yytext;
                                                                return DNS_USE_CACHE; }
 <INITIAL>{DNS_USE_FAILOVER}    { count(); yylval.strval=yytext;
@@ -524,6 +528,8 @@ EAT_ABLE    [\ \t\b\r]
                                                                return DNS_CACHE_GC_INT; }
 <INITIAL>{DNS_CACHE_DEL_NONEXP}        { count(); yylval.strval=yytext;
                                                                return DNS_CACHE_DEL_NONEXP; }
+<INITIAL>{DST_BLST_INIT}       { count(); yylval.strval=yytext;
+                                                               return DST_BLST_INIT; }
 <INITIAL>{USE_DST_BLST}        { count(); yylval.strval=yytext;
                                                                return USE_DST_BLST; }
 <INITIAL>{DST_BLST_MEM}        { count(); yylval.strval=yytext;

diff --git a/cfg.y b/cfg.y
index 79ee1de..5d1c465 100644 (file)
--- a/cfg.y
+++ b/cfg.y
@@ -292,6 +292,7 @@ static struct socket_id* mk_listen_id(char*, int, int);
 %token DNS_SERVERS_NO
 %token DNS_USE_SEARCH
 %token DNS_SEARCH_FMATCH
+%token DNS_CACHE_INIT
 %token DNS_USE_CACHE
 %token DNS_USE_FAILOVER
 %token DNS_CACHE_FLAGS
@@ -302,6 +303,7 @@ static struct socket_id* mk_listen_id(char*, int, int);
 %token DNS_CACHE_GC_INT
 %token DNS_CACHE_DEL_NONEXP
 /*blacklist*/
+%token DST_BLST_INIT
 %token USE_DST_BLST
 %token DST_BLST_MEM
 %token DST_BLST_TTL
@@ -630,7 +632,9 @@ assign_stm:
        | DNS_USE_SEARCH error { yyerror("boolean value expected"); }
        | DNS_SEARCH_FMATCH EQUAL NUMBER   { default_core_cfg.dns_search_fmatch=$3; }
        | DNS_SEARCH_FMATCH error { yyerror("boolean value expected"); }
-       | DNS_USE_CACHE EQUAL NUMBER   { IF_DNS_CACHE(use_dns_cache=$3); }
+       | DNS_CACHE_INIT EQUAL NUMBER   { IF_DNS_CACHE(dns_cache_init=$3); }
+       | DNS_CACHE_INIT error { yyerror("boolean value expected"); }
+       | DNS_USE_CACHE EQUAL NUMBER   { IF_DNS_CACHE(default_core_cfg.use_dns_cache=$3); }
        | DNS_USE_CACHE error { yyerror("boolean value expected"); }
        | DNS_USE_FAILOVER EQUAL NUMBER   { IF_DNS_FAILOVER(default_core_cfg.use_dns_failover=$3);}
        | DNS_USE_FAILOVER error { yyerror("boolean value expected"); }
@@ -648,6 +652,8 @@ assign_stm:
        | DNS_CACHE_GC_INT error { yyerror("boolean value expected"); }
        | DNS_CACHE_DEL_NONEXP EQUAL NUMBER   { IF_DNS_CACHE(default_core_cfg.dns_cache_del_nonexp=$3); }
        | DNS_CACHE_DEL_NONEXP error { yyerror("boolean value expected"); }
+       | DST_BLST_INIT EQUAL NUMBER   { IF_DST_BLACKLIST(dst_blacklist_init=$3); }
+       | DST_BLST_INIT error { yyerror("boolean value expected"); }
        | USE_DST_BLST EQUAL NUMBER   { IF_DST_BLACKLIST(default_core_cfg.use_dst_blacklist=$3); }
        | USE_DST_BLST error { yyerror("boolean value expected"); }
        | DST_BLST_MEM EQUAL NUMBER   { IF_DST_BLACKLIST(default_core_cfg.blst_max_mem=$3); }

diff --git a/cfg_core.c b/cfg_core.c
index a1e4bd8..72e68ea 100644 (file)
--- a/cfg_core.c
+++ b/cfg_core.c
@@ -67,6 +67,7 @@ struct cfg_group_core default_core_cfg = {
        0,  /* dns_reinit */
        /* DNS cache */
 #ifdef USE_DNS_CACHE
+       1,  /* use_dns_cache -- on by default */
        0,  /* dns_cache_flags */
        0,  /* use_dns_failover -- off by default */
        0,  /* dns_srv_lb -- off by default */
@@ -84,7 +85,7 @@ cfg_def_t core_cfg_def[] = {
        {"debug",       CFG_VAR_INT,    0, 0, 0, 0, "debug level"},
 #ifdef USE_DST_BLACKLIST
        /* blacklist */
-       {"use_dst_blacklist",   CFG_VAR_INT,    0, 0, 0, 0,
+       {"use_dst_blacklist",   CFG_VAR_INT,    0, 1, use_dst_blacklist_fixup, 0,
                "enable/disable destination blacklisting"},
        {"dst_blacklist_expire",        CFG_VAR_INT,    0, 0, 0, 0,
                "how much time (in s) a blacklisted destination is kept in the list"},
@@ -126,6 +127,8 @@ cfg_def_t core_cfg_def[] = {
                "set to 1 in order to reinitialize the DNS resolver"},
        /* DNS cache */
 #ifdef USE_DNS_CACHE
+       {"use_dns_cache",       CFG_VAR_INT,    0, 1, use_dns_cache_fixup, 0,
+               "enable/disable the dns cache"},
        {"dns_cache_flags",     CFG_VAR_INT,    0, 4, 0, fix_dns_flags,
                "dns cache specific resolver flags "
                "(1=ipv4 only, 2=ipv6 only, 4=prefer ipv6"},

diff --git a/cfg_core.h b/cfg_core.h
index 06b1d43..d8cbb1c 100644 (file)
--- a/cfg_core.h
+++ b/cfg_core.h
@@ -67,6 +67,7 @@ struct cfg_group_core {
        int dns_reinit;
        /* DNS cache */
 #ifdef USE_DNS_CACHE
+       int use_dns_cache;
        int dns_cache_flags;
        int use_dns_failover;
        int dns_srv_lb;

diff --git a/dns_cache.c b/dns_cache.c
index 62399ac..f7ffd63 100644 (file)
--- a/dns_cache.c
+++ b/dns_cache.c
@@ -41,6 +41,7 @@
  *  2007-08-17  dns_cache_del_nonexp config option is introduced (Miklos)
  *  2008-02-04  DNS cache options are adapted for the configuration
  *             framework (Miklos)
+ *  2008-02-11  dns_cache_init cfg parameter is introduced (Miklos)
  */
 
 #ifdef USE_DNS_CACHE
@@ -87,7 +88,7 @@
 #define MAX_CNAME_CHAIN  10
 #define SPACE_FORMAT "    " /* format of view output */
 
-
+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 */
@@ -299,7 +300,7 @@ void fix_dns_flags(str *name)
  */
 int use_dns_failover_fixup(void *handle, str *name, void **val)
 {
-       if ((int)(long)(*val) && !use_dns_cache) {
+       if ((int)(long)(*val) && !cfg_get(core, handle, use_dns_cache)) {
                LOG(L_ERR, "ERROR: use_dns_failover_fixup(): "
                        "DNS cache is turned off, failover cannot be enabled. "
                        "(set use_dns_cache to 1)\n");
@@ -308,6 +309,26 @@ int use_dns_failover_fixup(void *handle, str *name, void **val)
        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 *name, void **val)
+{
+       if ((int)(long)(*val) && !dns_cache_init) {
+               LOG(L_ERR, "ERROR: use_dns_cache_fixup(): "
+                       "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)) {
+               LOG(L_ERR, "ERROR: use_dns_failover_fixup(): "
+                       "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 *name, void **val)
 {
@@ -323,6 +344,13 @@ 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*)){
@@ -374,6 +402,8 @@ int init_dns_cache()
 
        /* 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);
 
@@ -399,7 +429,11 @@ error:
 }
 
 #ifdef USE_DNS_CACHE_STATS
-int init_dns_cache_stats(int iproc_num) {
+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);
@@ -2225,7 +2259,7 @@ struct hostent* dns_resolvehost(char* name)
 {
        str host;
 
-       if ((use_dns_cache==0) || (dns_hash==0)){ /* not init yet */
+       if ((cfg_get(core, core_cfg, use_dns_cache)==0) || (dns_hash==0)){ /* not init yet */
                return _resolvehost(name);
        }
        host.s=name;
@@ -2250,7 +2284,7 @@ struct hostent* dns_sip_resolvehost(str* name, unsigned short* port,
        struct ip_addr ip;
        int ret;
 
-       if ((use_dns_cache==0) || (dns_hash==0)){
+       if ((cfg_get(core, core_cfg, use_dns_cache==0)) || (dns_hash==0)){
                /* not init or off => use normal, non-cached version */
                return _sip_resolvehost(name, port, proto);
        }
@@ -2282,7 +2316,7 @@ struct hostent* dns_srv_sip_resolvehost(str* name, unsigned short* port,
        str srv_name;
        char srv_proto;
 
-       if ((use_dns_cache==0) || (dns_hash==0)){
+       if ((cfg_get(core, core_cfg, use_dns_cache)==0) || (dns_hash==0)){
                /* not init or off => use normal, non-cached version */
                return _sip_resolvehost(name, port, proto);
        }
@@ -3172,7 +3206,7 @@ int dns_get_server_state(void)
 /* rpc functions */
 void dns_cache_mem_info(rpc_t* rpc, void* ctx)
 {
-       if (!use_dns_cache){
+       if (!cfg_get(core, core_cfg, use_dns_cache)){
                rpc->fault(ctx, 500, "dns cache support disabled (see use_dns_cache)");
                return;
        }
@@ -3186,7 +3220,7 @@ void dns_cache_debug(rpc_t* rpc, void* ctx)
        struct dns_hash_entry* e;
        ticks_t now;
 
-       if (!use_dns_cache){
+       if (!cfg_get(core, core_cfg, use_dns_cache)){
                rpc->fault(ctx, 500, "dns cache support disabled (see use_dns_cache)");
                return;
        }
@@ -3255,7 +3289,7 @@ void dns_cache_stats_get(rpc_t* rpc, void* c)
        };
 
 
-       if (!use_dns_cache) {
+       if (!cfg_get(core, core_cfg, use_dns_cache)) {
                rpc->fault(c, 500, "dns cache support disabled");
                return;
        }
@@ -3300,7 +3334,7 @@ void dns_cache_debug_all(rpc_t* rpc, void* ctx)
        int i;
        ticks_t now;
 
-       if (!use_dns_cache){
+       if (!cfg_get(core, core_cfg, use_dns_cache)){
                rpc->fault(ctx, 500, "dns cache support disabled (see use_dns_cache)");
                return;
        }
@@ -3380,7 +3414,7 @@ void dns_cache_view(rpc_t* rpc, void* ctx)
        ticks_t now;
        str s;
 
-       if (!use_dns_cache){
+       if (!cfg_get(core, core_cfg, use_dns_cache)){
                rpc->fault(ctx, 500, "dns cache support disabled (see use_dns_cache)");
                return;
        }
@@ -3488,7 +3522,7 @@ void dns_cache_flush(void)
 /* deletes all the entries from the cache */
 void dns_cache_delete_all(rpc_t* rpc, void* ctx)
 {
-       if (!use_dns_cache){
+       if (!cfg_get(core, core_cfg, use_dns_cache)){
                rpc->fault(ctx, 500, "dns cache support disabled (see use_dns_cache)");
                return;
        }
@@ -3637,7 +3671,7 @@ static void dns_cache_add_record(rpc_t* rpc, void* ctx, unsigned short type)
        ip_addr = 0;
        size = 0;
 
-       if (!use_dns_cache){
+       if (!cfg_get(core, core_cfg, use_dns_cache)){
                rpc->fault(ctx, 500, "dns cache support disabled (see use_dns_cache)");
                return;
        }
@@ -3844,7 +3878,7 @@ static void dns_cache_delete_record(rpc_t* rpc, void* ctx, unsigned short type)
        str name;
        int err, h, found=0;
 
-       if (!use_dns_cache){
+       if (!cfg_get(core, core_cfg, use_dns_cache)){
                rpc->fault(ctx, 500, "dns cache support disabled (see use_dns_cache)");
                return;
        }
@@ -3911,7 +3945,7 @@ void dns_set_server_state_rpc(rpc_t* rpc, void* ctx)
 {
        int     state;
 
-       if (!use_dns_cache){
+       if (!cfg_get(core, core_cfg, use_dns_cache)){
                rpc->fault(ctx, 500, "dns cache support disabled (see use_dns_cache)");
                return;
        }
@@ -3923,7 +3957,7 @@ void dns_set_server_state_rpc(rpc_t* rpc, void* ctx)
 /* prints the DNS server state */
 void dns_get_server_state_rpc(rpc_t* rpc, void* ctx)
 {
-       if (!use_dns_cache){
+       if (!cfg_get(core, core_cfg, use_dns_cache)){
                rpc->fault(ctx, 500, "dns cache support disabled (see use_dns_cache)");
                return;
        }

diff --git a/dns_cache.h b/dns_cache.h
index 8ba753d..f11865a 100644 (file)
--- a/dns_cache.h
+++ b/dns_cache.h
@@ -180,6 +180,7 @@ const char* dns_strerror(int err);
 
 void fix_dns_flags(str *name);
 int use_dns_failover_fixup(void *handle, str *name, void **val);
+int use_dns_cache_fixup(void *handle, str *name, void **val);
 int dns_cache_max_mem_fixup(void *handle, str *name, void **val);
 int init_dns_cache();
 #ifdef USE_DNS_CACHE_STATS

diff --git a/doc/dns.txt b/doc/dns.txt
index 1338ee2..b7f9f1b 100644 (file)
--- a/doc/dns.txt
+++ b/doc/dns.txt
@@ -258,6 +258,9 @@ DNS Cache and Failover Config Variables
       ones. The last-recently used entries are deleted first.
       Default: no
 
+   dns_cache_init = on | off - if off, the dns cache is not initialized
+      at startup and cannot be enabled runtime, that saves some memory.
+      Default: on
 
 DNS Cache Compile Options
 

diff --git a/doc/dst_blacklist.txt b/doc/dst_blacklist.txt
index be6872d..8130ff4 100644 (file)
--- a/doc/dst_blacklist.txt
+++ b/doc/dst_blacklist.txt
@@ -55,6 +55,9 @@ Config Variables
  dst_blacklist_gc_interval = time in s (default 60 s) - how often the 
   garbage collection will run (eliminating old, expired entries).
 
+ dst_blacklist_init = on | off (default on) - if off, the blacklist
+  is not initialized at startup and cannot be enabled runtime,
+  that saves some memory.
 
 Compile Options
 

diff --git a/dst_blacklist.c b/dst_blacklist.c
index 1ca0f81..0f19905 100644 (file)
--- a/dst_blacklist.c
+++ b/dst_blacklist.c
@@ -33,6 +33,7 @@
  *  2007-06-26  added hooks for search (andrei)
  *  2007-07-30  added dst_blacklist_del() and dst_blacklist_add_to()  (andrei)
  *  2007-07-30  dst blacklist measurements added (Gergo)
+ *  2008-02-11  dns_blacklist_init cfg parameter is introduced (Miklos)
  */
 
 
@@ -123,6 +124,7 @@ struct dst_blst_lst_head{
 #endif
 };
 
+int dst_blacklist_init=1; /* if 0, the dst blacklist is not initialized at startup */
 static struct timer_ln* blst_timer_h=0;
 
 static volatile unsigned int* blst_mem_used=0;
@@ -226,6 +228,12 @@ int register_blacklist_hook(struct blacklist_hook *h, int type)
        struct blacklist_hook* tmp;
        int new_max_hooks;
 
+       if (dst_blacklist_init==0) {
+               LOG(L_ERR, "register_blacklist_hook: blacklist is turned off, "
+                       "the hook cannot be registered\n");
+               goto error;
+       }
+
        switch(type){
                case DST_BLACKLIST_ADD_CB:
                        cb_lst=&blst_add_cb;
@@ -339,6 +347,7 @@ void destroy_dst_blacklist()
                blst_timer_h=0;
        }
 #ifdef BLST_LOCK_PER_BUCKET
+       if (dst_blst_hash)
                for(r=0; r<DST_BLST_HASH_SIZE; r++)
                        lock_destroy(&dst_blst_hash[r].lock);
 #elif defined BLST_LOCK_SET
@@ -390,6 +399,12 @@ int init_dst_blacklist()
        int r;
 #endif
 
+       if (dst_blacklist_init==0) {
+               /* the dst blacklist is turned off */
+               default_core_cfg.use_dst_blacklist=0;
+               return 0;
+       }
+
        ret=-1;
 #ifdef DST_BLACKLIST_HOOKS
        if (init_blacklist_hooks()!=0){
@@ -468,6 +483,9 @@ error:
 #ifdef USE_DST_BLACKLIST_STATS
 int init_dst_blacklist_stats(int iproc_num)
 {
+       /* do not initialize the stats array if the dst blacklist will not be used */
+       if (dst_blacklist_init==0) return 0;
+
        /* if it is already initialized */
        if (dst_blacklist_stats)
                shm_free(dst_blacklist_stats);
@@ -1095,6 +1113,20 @@ void dst_blst_add(rpc_t* rpc, void* ctx)
                rpc->fault(ctx, 400, "Failed to add the entry to the blacklist");
 }
 
+/* fixup function for use_dst_blacklist
+ * verifies that dst_blacklist_init is set to 1
+ */
+int use_dst_blacklist_fixup(void *handle, str *name, void **val)
+{
+       if ((int)(long)(*val) && !dst_blacklist_init) {
+               LOG(L_ERR, "ERROR: use_dst_blacklist_fixup(): "
+                       "dst blacklist is turned off by dst_blacklist_init=0, "
+                       "it cannot be enabled runtime.\n");
+               return -1;
+       }
+       return 0;
+}
+
 /* KByte to Byte conversion */
 int blst_max_mem_fixup(void *handle, str *name, void **val)
 {

diff --git a/dst_blacklist.h b/dst_blacklist.h
index 345274b..e2ca0b4 100644 (file)
--- a/dst_blacklist.h
+++ b/dst_blacklist.h
@@ -103,6 +103,7 @@ int dst_blacklist_del(struct dest_info* si, struct sip_msg* msg);
  */
 void dst_blst_flush(void);
 
+int use_dst_blacklist_fixup(void *handle, str *name, void **val);
 /* KByte to Byte conversion */
 int blst_max_mem_fixup(void *handle, str *name, void **val);
 

diff --git a/globals.h b/globals.h
index 04d5bc3..3750ae1 100644 (file)
--- a/globals.h
+++ b/globals.h
@@ -191,7 +191,7 @@ extern int rt_timer2_policy; /* "slow" timer, SCHED_OTHER */
 
 
 #ifdef USE_DNS_CACHE
-extern int use_dns_cache; /* 1 if the cache is enabled, 0 otherwise */
+extern int dns_cache_init; /* if 0, the DNS cache is not initialized at startup */
 extern unsigned int dns_timer_interval; /* gc timer interval in s */
 extern int dns_flags; /* default flags used for the  dns_*resolvehost
                     (compatibility wrappers) */
@@ -207,6 +207,7 @@ extern struct t_dns_cache_stats* dns_cache_stats;
 #endif /* USE_DNS_CACHE_STATS */
 #endif
 #ifdef USE_DST_BLACKLIST
+extern int dst_blacklist_init; /* if 0, the dst blacklist is not initialized at startup */
 extern unsigned int blst_timer_interval; /*blacklist gc timer interval (in s)*/
 
 #ifdef USE_DST_BLACKLIST_STATS

diff --git a/main.c b/main.c
index 162cd80..d12823f 100644 (file)
--- a/main.c
+++ b/main.c
@@ -371,9 +371,6 @@ int reply_to_via=0;
 int mcast_loopback = 0;
 int mcast_ttl = -1; /* if -1, don't touch it, use the default (usually 1) */
 #endif /* USE_MCAST */
-#ifdef USE_DNS_CACHE
-int use_dns_cache=1; /* 1 if the cache is enabled, 0 otherwise */
-#endif
 
 int tos = IPTOS_LOWDELAY;
 int pmtu_discovery = 0;
@@ -1652,12 +1649,10 @@ try_again:
                goto error;
        }
 #ifdef USE_DNS_CACHE
-       if (use_dns_cache && init_dns_cache()<0){
+       if (init_dns_cache()<0){
                LOG(L_CRIT, "could not initialize the dns cache, exiting...\n");
                goto error;
        }
-       if (use_dns_cache==0)
-               default_core_cfg.use_dns_failover=0; /* cannot work w/o dns_cache support */
 #ifdef USE_DNS_CACHE_STATS
        /* preinitializing before the nubmer of processes is determined */
        if (init_dns_cache_stats(1)<0){