From 9556ab31953b08ec4031e947d2357bde5f848100 Mon Sep 17 00:00:00 2001
From: Iryna Antsyferova <iryna.antsyferova@iopsys.eu>
Date: Tue, 25 Jun 2024 13:08:35 +0200
Subject: [PATCH] Implmenet dns cache support
---
res/res_pjsip.exports.in | 1 +
res/res_pjsip/pjsip_resolver.c | 68 +++++++++++++++++++++++++++
res/res_pjsip_outbound_registration.c | 25 ++++++++++
3 files changed, 94 insertions(+)
diff --git a/res/res_pjsip.exports.in b/res/res_pjsip.exports.in
index 58868e398f..4a0f2181bf 100644
--- a/res/res_pjsip.exports.in
+++ b/res/res_pjsip.exports.in
@@ -6,6 +6,7 @@
LINKER_SYMBOL_PREFIXast_copy_pj_str;
LINKER_SYMBOL_PREFIXast_copy_pj_str2;
LINKER_SYMBOL_PREFIXast_pjsip_rdata_get_endpoint;
+ LINKER_SYMBOL_PREFIXpjsip_resolver_*;
local:
*;
};
diff --git a/res/res_pjsip/pjsip_resolver.c b/res/res_pjsip/pjsip_resolver.c
index eb370117e5..792062087c 100644
--- a/res/res_pjsip/pjsip_resolver.c
+++ b/res/res_pjsip/pjsip_resolver.c
@@ -32,9 +32,14 @@
#include "include/res_pjsip_private.h"
#include "asterisk/taskprocessor.h"
#include "asterisk/threadpool.h"
+#include "asterisk/pjsip_resolver.h"
#ifdef HAVE_PJSIP_EXTERNAL_RESOLVER
+/*! DNS cache function pointers */
+dns_cache_get_addr_t get_dns_cache_addr = NULL;
+dns_cache_update_t update_dns_cache = NULL;
+
/*! \brief Structure which contains transport+port information for an active query */
struct sip_target {
/*! \brief The transport to be used */
@@ -59,8 +64,18 @@ struct host_track_entry {
AST_LIST_ENTRY(host_track_entry) next;
};
+/*! \brief Structure which contains cached resolved server addresses */
+struct dns_cache_entry {
+ char *host;
+ pjsip_server_addresses addresses;
+ int ttl;
+ time_t entry_time;
+ AST_LIST_ENTRY(dns_cache_entry) next;
+};
+
/*! \brief the list of all tracked hosts */
AST_LIST_HEAD(, host_track_entry) sip_resolve_track;
+AST_LIST_HEAD(, dns_cache_entry) sip_dns_cache;
/*! \brief compare the target host info with track record */
static int host_track_target_cmp(pjsip_host_info *host, struct host_track_entry *hostc)
@@ -266,6 +281,10 @@ struct sip_resolve {
pjsip_resolver_callback *callback;
/*! \brief User provided data */
void *token;
+ /*! \brief Hostname requested to resolve */
+ char host[NI_MAXHOST];
+ /*! \brief Minimum TTL for the queries resulting in viable server addresses */
+ int ttl;
};
/*! \brief Our own defined transports, reduces the size of sip_available_transports */
@@ -410,6 +429,18 @@ static int sip_resolve_invoke_user_callback(void *data)
sip_resolve_target_track(&resolve->target, &resolve->addresses);
+ if (update_dns_cache && get_dns_cache_addr && resolve->addresses.count != 0) {
+ ast_debug(2, "Updating DNS cache...\n");
+
+ if (!(*update_dns_cache)(resolve->host, &resolve->addresses, resolve->ttl)) {
+ ast_debug(2, "Getting addr from DNS cache\n");
+
+ if ((*get_dns_cache_addr)(resolve->host, &resolve->addresses)) {
+ ast_log(LOG_ERROR, "Failed to get addr from cache after updating!");
+ }
+ }
+ }
+
ast_debug(2, "[%p] Invoking user callback with '%d' addresses\n", resolve, resolve->addresses.count);
resolve->callback(resolve->addresses.count ? PJ_SUCCESS : PJLIB_UTIL_EDNSNOANSWERREC, resolve->token, &resolve->addresses);
@@ -541,6 +572,12 @@ static void sip_resolve_callback(const struct ast_dns_query_set *query_set)
ast_dns_record_get_data_size(record));
}
+ int min_ttl = ast_dns_result_get_lowest_ttl(result);
+ if (min_ttl > 0 && resolve->ttl < min_ttl) {
+ ast_debug(2, "Updating DNS TTL for query set from %d to %d\n", resolve->ttl, min_ttl);
+ resolve->ttl = min_ttl;
+ }
+
address_count++;
} else if (ast_dns_record_get_rr_type(record) == T_SRV) {
if (have_naptr) {
@@ -735,6 +772,19 @@ static void sip_resolve(pjsip_resolver_t *resolver, pj_pool_t *pool, const pjsip
return;
}
+ if (get_dns_cache_addr) {
+ ast_debug(2, "Checking DNS cache...(%s)\n", host);
+ pjsip_server_addresses addresses = { .count = 0, };
+
+ if (!(*get_dns_cache_addr)(host, &addresses)) {
+ ast_debug(2, "Addr found in DNS cache\n");
+
+ cb(PJ_SUCCESS, token, &addresses);
+ return;
+ }
+ ast_debug(2, "No addr found in DNS cache\n");
+ }
+
resolve = ao2_alloc_options(sizeof(*resolve), sip_resolve_destroy, AO2_ALLOC_OPT_LOCK_NOLOCK);
if (!resolve) {
cb(PJ_ENOMEM, token, NULL);
@@ -744,6 +794,8 @@ static void sip_resolve(pjsip_resolver_t *resolver, pj_pool_t *pool, const pjsip
pj_memcpy(&resolve->target, target, sizeof(*target));
resolve->callback = cb;
resolve->token = token;
+ strncpy(resolve->host, host, NI_MAXHOST);
+ resolve->ttl = 0;
if (AST_VECTOR_INIT(&resolve->resolving, 4)) {
ao2_ref(resolve, -1);
@@ -869,6 +921,22 @@ static void sip_check_transport(pj_pool_t *pool, pjsip_transport_type_e transpor
}
}
+/* External API to set DNS cache function pointers */
+void pjsip_resolver_set_dns_cache(dns_cache_get_addr_t get_addr, dns_cache_update_t update_cache)
+{
+ ast_debug(3, "Setting DNS cache control function pointers\n");
+ get_dns_cache_addr = get_addr;
+ update_dns_cache = update_cache;
+}
+
+/* External API to clear DNS cache function pointers */
+void pjsip_resolver_clear_dns_cache(void)
+{
+ ast_debug(3, "Clearing DNS cache control function pointers\n");
+ get_dns_cache_addr = NULL;
+ update_dns_cache = NULL;
+}
+
/*! \brief External resolver implementation for PJSIP */
static pjsip_ext_resolver ext_resolver = {
.resolve = sip_resolve,
diff --git a/res/res_pjsip_outbound_registration.c b/res/res_pjsip_outbound_registration.c
index 6ed2141d69..9f91bc7eb9 100644
--- a/res/res_pjsip_outbound_registration.c
+++ b/res/res_pjsip_outbound_registration.c
@@ -286,6 +286,10 @@ static int set_outbound_initial_authentication_credentials(pjsip_regc *regc,
/*! \brief Some thread local storage used to determine if the running thread invoked the callback */
AST_THREADSTORAGE(register_callback_invoked);
+/*! DNS cache function pointer typedefs */
+typedef void (*dns_cache_update_addr_t)(void);
+typedef void (*dns_cache_clear_t)(void);
+
/*! \brief Amount of buffer time (in seconds) before expiration that we re-register at */
#define REREGISTER_BUFFER_TIME 10
@@ -505,6 +509,10 @@ static AO2_GLOBAL_OBJ_STATIC(current_states);
/*! subscription id for network change events */
static struct stasis_subscription *network_change_sub;
+/*! DNS cache function pointers */
+dns_cache_update_addr_t update_dns_cache_addr = NULL;
+dns_cache_clear_t clear_dns_cache = NULL;
+
/*! \brief hashing function for state objects */
static int registration_state_hash(const void *obj, const int flags)
{
@@ -3142,6 +3150,23 @@ static void network_change_stasis_cb(void *data, struct stasis_subscription *sub
reregister_all();
}
+/* External API to set DNS cache control function pointers */
+void pjsip_outbound_registration_set_dns_cache_control(dns_cache_update_addr_t update_addr,
+ dns_cache_clear_t clear_cache)
+{
+ ast_debug(3, "Setting DNS cache control function pointers\n");
+ update_dns_cache_addr = update_addr;
+ clear_dns_cache = clear_cache;
+}
+
+/* External API to clear DNS cache control function pointers */
+void pjsip_outbound_registration_clear_dns_cache_control(void)
+{
+ ast_debug(3, "Clearing DNS cache control function pointers\n");
+ update_dns_cache_addr = NULL;
+ clear_dns_cache = NULL;
+}
+
static int unload_module(void)
{
int remaining;
--
GitLab