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dns_cache: Fix several issues related to cache memory.
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@pymumu
pymumu committed Nov 30, 2023
1 parent d094a70 commit 7997300
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Showing 5 changed files with 84 additions and 24 deletions.
4 changes: 2 additions & 2 deletions package/luci-compat/files/luci/model/cbi/smartdns/smartdns.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -135,7 +135,7 @@ o = s:taboption("advanced", Flag, "tls_server", translate("DOT Server"), transla
o.rmempty = false
o.default = o.disabled
o.cfgvalue = function(...)
return Flag.cfgvalue(...) or "1"
return Flag.cfgvalue(...) or "0"
end

o = s:taboption("advanced", Value, "tls_server_port", translate("DOT Server Port"), translate("Smartdns DOT server port."))
Expand All @@ -150,7 +150,7 @@ o = s:taboption("advanced", Flag, "doh_server", translate("DOH Server"), transla
o.rmempty = false
o.default = o.disabled
o.cfgvalue = function(...)
return Flag.cfgvalue(...) or "1"
return Flag.cfgvalue(...) or "0"
end

o = s:taboption("advanced", Value, "doh_server_port", translate("DOH Server Port"), translate("Smartdns DOH server port."))
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35 changes: 34 additions & 1 deletion src/dns_cache.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
#define DNS_CACHE_HITNUM_STEP 3
#define DNS_CACHE_HITNUM_STEP_MAX 6
#define DNS_CACHE_READ_TIMEOUT 60
#define DNS_CACHE_FAIL_TIMEOUT (60 * 5)
#define EXPIRED_DOMAIN_PREFETCH_TIME (3600 * 8)

struct dns_cache_head {
Expand Down Expand Up @@ -168,9 +169,18 @@ static void dns_cache_expired(struct tw_base *base, struct tw_timer_list *timer,
}

if (dns_cache_head.timeout_callback) {
if (dns_cache_head.timeout_callback(dns_cache) != 0) {
dns_cache_tmout_action_t tmout_act = dns_cache_head.timeout_callback(dns_cache);
switch (tmout_act) {
case DNS_CACHE_TMOUT_ACTION_OK:
break;
case DNS_CACHE_TMOUT_ACTION_DEL:
dns_cache_release(dns_cache);
return;
case DNS_CACHE_TMOUT_ACTION_RETRY:
dns_timer_mod(&dns_cache->timer, DNS_CACHE_FAIL_TIMEOUT);
return;
default:
break;
}
}

Expand Down Expand Up @@ -201,6 +211,7 @@ static int _dns_cache_replace(struct dns_cache_key *cache_key, int rcode, int tt
/* update cache data */
pthread_mutex_lock(&dns_cache_head.lock);
dns_cache->del_pending = 0;
dns_cache->info.rcode = rcode;
dns_cache->info.qtype = cache_key->qtype;
dns_cache->info.query_flag = cache_key->query_flag;
dns_cache->info.ttl = ttl;
Expand Down Expand Up @@ -364,6 +375,23 @@ int dns_cache_insert(struct dns_cache_key *cache_key, int rcode, int ttl, int sp
return _dns_cache_insert(&info, cache_data, &dns_cache_head.cache_list, timeout);
}

int dns_cache_update_timer(struct dns_cache_key *key, int timeout)
{
struct dns_cache *dns_cache = dns_cache_lookup(key);
if (dns_cache == NULL) {
return -1;
}

pthread_mutex_lock(&dns_cache_head.lock);
dns_timer_mod(&dns_cache->timer, timeout);
dns_cache->del_pending = 0;
pthread_mutex_unlock(&dns_cache_head.lock);

dns_cache_release(dns_cache);

return 0;
}

struct dns_cache *dns_cache_lookup(struct dns_cache_key *cache_key)
{
uint32_t key = 0;
Expand Down Expand Up @@ -466,6 +494,11 @@ int dns_cache_is_visited(struct dns_cache *dns_cache)
return dns_cache->info.is_visited;
}

int dns_cache_total_num(void)
{
return atomic_read(&dns_cache_head.num);
}

void dns_cache_delete(struct dns_cache *dns_cache)
{
pthread_mutex_lock(&dns_cache_head.lock);
Expand Down
12 changes: 11 additions & 1 deletion src/dns_cache.h
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Original file line number Diff line number Diff line change
Expand Up @@ -124,7 +124,13 @@ const char *dns_cache_get_dns_group_name(struct dns_cache *dns_cache);

struct dns_cache_data *dns_cache_new_data_packet(void *packet, size_t packet_len);

typedef int (*dns_cache_callback)(struct dns_cache *dns_cache);
typedef enum DNS_CACHE_TMOUT_ACTION {
DNS_CACHE_TMOUT_ACTION_OK = 0,
DNS_CACHE_TMOUT_ACTION_DEL = 1,
DNS_CACHE_TMOUT_ACTION_RETRY = 2,
} dns_cache_tmout_action_t;

typedef dns_cache_tmout_action_t (*dns_cache_callback)(struct dns_cache *dns_cache);

int dns_cache_init(int size, dns_cache_callback timeout_callback);

Expand All @@ -136,6 +142,10 @@ int dns_cache_insert(struct dns_cache_key *key, int rcode, int ttl, int speed, i

struct dns_cache *dns_cache_lookup(struct dns_cache_key *key);

int dns_cache_total_num(void);

int dns_cache_update_timer(struct dns_cache_key *key, int timeout);

void dns_cache_delete(struct dns_cache *dns_cache);

void dns_cache_get(struct dns_cache *dns_cache);
Expand Down
51 changes: 34 additions & 17 deletions src/dns_server.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1012,7 +1012,8 @@ static int _dns_add_rrs(struct dns_server_post_context *context)
}

if (request->rcode != DNS_RC_NOERROR) {
tlog(TLOG_INFO, "result: %s, qtype: %d, rtcode: %d", domain, context->qtype, request->rcode);
tlog(TLOG_INFO, "result: %s, qtype: %d, rtcode: %d, id: %d", domain, context->qtype, request->rcode,
request->id);
}

return ret;
Expand Down Expand Up @@ -1694,6 +1695,16 @@ static int _dns_cache_specify_packet(struct dns_server_post_context *context)
return _dns_cache_packet(context);
}

static int _dns_cache_try_keep_old_cache(struct dns_request *request)
{
struct dns_cache_key cache_key;
cache_key.dns_group_name = request->dns_group_name;
cache_key.domain = request->domain;
cache_key.qtype = request->qtype;
cache_key.query_flag = request->server_flags;
return dns_cache_update_timer(&cache_key, DNS_SERVER_TMOUT_TTL);
}

static int _dns_cache_reply_packet(struct dns_server_post_context *context)
{
struct dns_request *request = context->request;
Expand All @@ -1707,6 +1718,8 @@ static int _dns_cache_reply_packet(struct dns_server_post_context *context)
context->reply_ttl = DNS_SERVER_FAIL_TTL;
/* Do not cache record if cannot connect to remote */
if (request->remote_server_fail == 0 && context->packet->head.rcode == DNS_RC_SERVFAIL) {
/* Try keep old cache if server fail */
_dns_cache_try_keep_old_cache(request);
return 0;
}

Expand Down Expand Up @@ -3712,8 +3725,9 @@ static int dns_server_resolve_callback(const char *domain, dns_result_type rtype
}

if (rtype == DNS_QUERY_RESULT) {
tlog(TLOG_DEBUG, "query result from server %s:%d, type: %d", dns_client_get_server_ip(server_info),
dns_client_get_server_port(server_info), dns_client_get_server_type(server_info));
tlog(TLOG_DEBUG, "query result from server %s:%d, type: %d, rcode: %d, id: %d",
dns_client_get_server_ip(server_info), dns_client_get_server_port(server_info),
dns_client_get_server_type(server_info), packet->head.rcode, request->id);

if (request->passthrough == 1 && atomic_read(&request->notified) == 0) {
struct dns_server_post_context context;
Expand Down Expand Up @@ -6663,13 +6677,13 @@ static int _dns_server_second_ping_check(struct dns_request *request)
return ret;
}

static int _dns_server_prefetch_domain(struct dns_cache *dns_cache)
static dns_cache_tmout_action_t _dns_server_prefetch_domain(struct dns_cache *dns_cache)
{
/* If there are still hits, continue pre-fetching */
struct dns_server_query_option server_query_option;
int hitnum = dns_cache_hitnum_dec_get(dns_cache);
if (hitnum <= 0) {
return -1;
return DNS_CACHE_TMOUT_ACTION_DEL;
}

/* start prefetch domain */
Expand All @@ -6681,23 +6695,26 @@ static int _dns_server_prefetch_domain(struct dns_cache *dns_cache)
if (_dns_server_prefetch_request(dns_cache->info.domain, dns_cache->info.qtype, &server_query_option,
PREFETCH_FLAGS_NO_DUALSTACK) != 0) {
tlog(TLOG_ERROR, "prefetch domain %s, qtype %d, failed.", dns_cache->info.domain, dns_cache->info.qtype);
return -1;
return DNS_CACHE_TMOUT_ACTION_RETRY;
}

return 0;
return DNS_CACHE_TMOUT_ACTION_OK;
}

static int _dns_server_prefetch_expired_domain(struct dns_cache *dns_cache)
static dns_cache_tmout_action_t _dns_server_prefetch_expired_domain(struct dns_cache *dns_cache)
{
time_t ttl = _dns_server_expired_cache_ttl(dns_cache);
if (ttl <= 1) {
return -1;
return DNS_CACHE_TMOUT_ACTION_DEL;
}

/* start prefetch domain */
tlog(TLOG_DEBUG, "expired domain, prefetch by cache %s, qtype %d, ttl %llu, insert time %llu replace time %llu",
dns_cache->info.domain, dns_cache->info.qtype, (unsigned long long)ttl,
(unsigned long long)dns_cache->info.insert_time, (unsigned long long)dns_cache->info.replace_time);
tlog(TLOG_DEBUG,
"expired domain, total %d, prefetch by cache %s, qtype %d, ttl %llu, rcode %d, insert time %llu replace time "
"%llu",
dns_cache_total_num(), dns_cache->info.domain, dns_cache->info.qtype, (unsigned long long)ttl,
dns_cache->info.rcode, (unsigned long long)dns_cache->info.insert_time,
(unsigned long long)dns_cache->info.replace_time);

struct dns_server_query_option server_query_option;
server_query_option.dns_group_name = dns_cache_get_dns_group_name(dns_cache);
Expand All @@ -6707,16 +6724,16 @@ static int _dns_server_prefetch_expired_domain(struct dns_cache *dns_cache)
if (_dns_server_prefetch_request(dns_cache->info.domain, dns_cache->info.qtype, &server_query_option,
PREFETCH_FLAGS_EXPIRED) != 0) {
tlog(TLOG_DEBUG, "prefetch domain %s, qtype %d, failed.", dns_cache->info.domain, dns_cache->info.qtype);
return -1;
return DNS_CACHE_TMOUT_ACTION_RETRY;
}

return 0;
return DNS_CACHE_TMOUT_ACTION_OK;
}

static int _dns_server_cache_expired(struct dns_cache *dns_cache)
static dns_cache_tmout_action_t _dns_server_cache_expired(struct dns_cache *dns_cache)
{
if (dns_cache->info.rcode != DNS_RC_NOERROR) {
return -1;
return DNS_CACHE_TMOUT_ACTION_DEL;
}

if (dns_conf_prefetch == 1 && _dns_cache_is_specify_packet(dns_cache->info.qtype) != 0) {
Expand All @@ -6727,7 +6744,7 @@ static int _dns_server_cache_expired(struct dns_cache *dns_cache)
}
}

return -1;
return DNS_CACHE_TMOUT_ACTION_DEL;
}

static void _dns_server_tcp_idle_check(void)
Expand Down
6 changes: 3 additions & 3 deletions src/lib/timer_wheel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -158,7 +158,7 @@ void tw_add_timer(struct tw_base *base, struct tw_timer_list *timer)

pthread_spin_lock(&base->lock);
{
timer->expires += base->jiffies;
timer->expires += base->jiffies - 1;
_tw_add_timer(base, timer);
}
pthread_spin_unlock(&base->lock);
Expand Down Expand Up @@ -190,7 +190,7 @@ int tw_mod_timer_pending(struct tw_base *base, struct tw_timer_list *timer, unsi

pthread_spin_lock(&base->lock);
{
timer->expires = expires + base->jiffies;
timer->expires = expires + base->jiffies - 1;
ret = __mod_timer(base, timer, 1);
}
pthread_spin_unlock(&base->lock);
Expand All @@ -208,7 +208,7 @@ int tw_mod_timer(struct tw_base *base, struct tw_timer_list *timer, unsigned lon
goto unblock;
}

timer->expires = expires + base->jiffies;
timer->expires = expires + base->jiffies - 1;

ret = __mod_timer(base, timer, 0);
}
Expand Down

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