improve DNS resolver:

- supports IPv6 DNS servers
- supports nameserver lists with both IPv4 and IPv6 servers

include/belle-sip/resolver.h

@@ -99,14 +99,14 @@ BELLESIP_EXPORT void belle_sip_resolver_context_cancel(belle_sip_resolver_contex
  * Lookups the source address from local interface that can be used to connect to a destination address.
  * local_port is only used to be assigned into the result source address.
 **/
-void belle_sip_get_src_addr_for(const struct sockaddr *dest, socklen_t destlen, struct sockaddr *src, socklen_t *srclen, int local_port);
+BELLESIP_EXPORT void belle_sip_get_src_addr_for(const struct sockaddr *dest, socklen_t destlen, struct sockaddr *src, socklen_t *srclen, int local_port);
 
 /**
  * This function will transform a V4 to V6 mapped address to a pure V4 and write it into result, or will just copy it otherwise.
  * The memory for v6 and result may be the same, in which case processing is done in place or no copy is done.
  * The pointer to result must have sufficient storage, typically a struct sockaddr_storage.
 **/ 
-void belle_sip_address_remove_v4_mapping(const struct sockaddr *v6, struct sockaddr *result, socklen_t *result_len);
+BELLESIP_EXPORT void belle_sip_address_remove_v4_mapping(const struct sockaddr *v6, struct sockaddr *result, socklen_t *result_len);
 
 BELLE_SIP_END_DECLS
 

include/belle-sip/sipstack.h

@@ -93,6 +93,20 @@ BELLESIP_EXPORT const char * belle_sip_stack_get_dns_user_hosts_file(const belle
 **/
 BELLESIP_EXPORT void belle_sip_stack_set_dns_user_hosts_file(belle_sip_stack_t *stack, const char *hosts_file);
 
+
+/**
+ * Get the overriding DNS resolv.conf file.
+ * @return The path to the overriding DNS resolv.conf file.
+**/
+BELLESIP_EXPORT const char * belle_sip_stack_get_dns_resolv_conf_file(const belle_sip_stack_t *stack);
+
+/**
+ * Can be used to load an overriding DNS resolv.conf file for tests.
+ * @param stack
+ * @param hosts_file The path to the overriding DNS resolv.conf file to load.
+**/
+BELLESIP_EXPORT void belle_sip_stack_set_dns_resolv_conf_file(belle_sip_stack_t *stack, const char *hosts_file);
+
 /**
  * Returns the time interval in seconds after which a connection must be closed when inactive.
 **/

src/belle_sip_internal.h

@@ -502,6 +502,7 @@ struct belle_sip_stack{
 	int resolver_send_error;	/* used to simulate network error*/
 	int dscp;
 	char *dns_user_hosts_file; /* used to load additional hosts file for tests */
+	char *dns_resolv_conf; /*used to load custom resolv.conf, for tests*/
 	unsigned char dns_srv_enabled;
 };
 

src/belle_sip_resolver.c

@@ -152,10 +152,7 @@ void belle_sip_resolver_context_init(belle_sip_resolver_context_t *obj, belle_si
 }
 
 static struct dns_resolv_conf *resconf(belle_sip_simple_resolver_context_t *ctx) {
-#if !_WIN32 && !HAVE_RESINIT
-/*#if !_WIN32 && (!HAVE_RESINIT || !TARGET_OS_IPHONE)*/
 	const char *path;
-#endif
 	int error;
 
 	if (ctx->resconf)
@@ -165,44 +162,62 @@ static struct dns_resolv_conf *resconf(belle_sip_simple_resolver_context_t *ctx)
 		belle_sip_error("%s dns_resconf_open error: %s", __FUNCTION__, dns_strerror(error));
 		return NULL;
 	}
-
+	
+	path=belle_sip_stack_get_dns_resolv_conf_file(ctx->base.stack);
+	if (!path){
 #ifdef _WIN32
-	error = dns_resconf_loadwin(ctx->resconf);
-	if (error) {
-		belle_sip_error("%s dns_resconf_loadwin error", __FUNCTION__);
-	}
+		error = dns_resconf_loadwin(ctx->resconf);
+		if (error) {
+			belle_sip_error("%s dns_resconf_loadwin error", __FUNCTION__);
+		}
 #elif ANDROID
-	error = dns_resconf_loadandroid(ctx->resconf);
-	if (error) {
-		belle_sip_error("%s dns_resconf_loadandroid error", __FUNCTION__);
-	}
+		error = dns_resconf_loadandroid(ctx->resconf);
+		if (error) {
+			belle_sip_error("%s dns_resconf_loadandroid error", __FUNCTION__);
+		}
 #elif HAVE_RESINIT
 /*#elif HAVE_RESINIT && TARGET_OS_IPHONE*/
-	error = dns_resconf_loadfromresolv(ctx->resconf);
-	if (error) {
-		belle_sip_error("%s dns_resconf_loadfromresolv error", __FUNCTION__);
-	}
+		error = dns_resconf_loadfromresolv(ctx->resconf);
+		if (error) {
+			belle_sip_error("%s dns_resconf_loadfromresolv error", __FUNCTION__);
+		}
 #else
-	path = "/etc/resolv.conf";
-	error = dns_resconf_loadpath(ctx->resconf, path);
-	if (error) {
-		belle_sip_error("%s dns_resconf_loadpath error [%s]: %s", __FUNCTION__, path, dns_strerror(error));
-		return NULL;
-	}
+		path = "/etc/resolv.conf";
+		error = dns_resconf_loadpath(ctx->resconf, path);
+		if (error) {
+			belle_sip_error("%s dns_resconf_loadpath error [%s]: %s", __FUNCTION__, path, dns_strerror(error));
+			return NULL;
+		}
 
-	path = "/etc/nsswitch.conf";
-	error = dns_nssconf_loadpath(ctx->resconf, path);
-	if (error) {
-		belle_sip_message("%s dns_nssconf_loadpath error [%s]: %s", __FUNCTION__, path, dns_strerror(error));
-	}
+		path = "/etc/nsswitch.conf";
+		error = dns_nssconf_loadpath(ctx->resconf, path);
+		if (error) {
+			belle_sip_message("%s dns_nssconf_loadpath error [%s]: %s", __FUNCTION__, path, dns_strerror(error));
+		}
 #endif
+	}else{
+		error = dns_resconf_loadpath(ctx->resconf, path);
+		if (error) {
+			belle_sip_error("%s dns_resconf_loadpath() of custom file error [%s]: %s", __FUNCTION__, path, dns_strerror(error));
+			return NULL;
+		}
+	}
+	
 	if (error==0){
 		char ip[64];
 		char serv[10];
-		struct sockaddr *ns_addr=(struct sockaddr*)&ctx->resconf->nameserver[0];
-		getnameinfo(ns_addr,sizeof(struct sockaddr_storage),ip,sizeof(ip),serv,sizeof(serv),NI_NUMERICHOST|NI_NUMERICSERV);
-		belle_sip_message("Loaded DNS server: %s",ip);
-		ctx->resconf->iface.ss_family=ns_addr->sa_family;
+		int using_ipv6=FALSE;
+		int i;
+		
+		belle_sip_message("Resolver is using DNS server(s):");
+		for(i=0;i<sizeof(ctx->resconf->nameserver)/sizeof(ctx->resconf->nameserver[0]);++i){
+			struct sockaddr *ns_addr=(struct sockaddr*)&ctx->resconf->nameserver[i];
+			if (ns_addr->sa_family==AF_UNSPEC) break;
+			getnameinfo(ns_addr,sizeof(struct sockaddr_storage),ip,sizeof(ip),serv,sizeof(serv),NI_NUMERICHOST|NI_NUMERICSERV);
+			belle_sip_message("\t%s",ip);
+			if (ns_addr->sa_family==AF_INET6) using_ipv6=TRUE;
+		}
+		ctx->resconf->iface.ss_family=using_ipv6 ? AF_INET6 : AF_INET;
 	}else{
 		belle_sip_error("Error loading dns server addresses.");
 	}

src/dns.c

@@ -115,6 +115,8 @@
 #include <resolv.h>
 #endif
 
+//#define DNS_DEBUG 1
+
 /*
  * C O M P I L E R  A N N O T A T I O N S
  *
@@ -184,7 +186,7 @@
  *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
-int dns_debug = 0;
+int dns_debug = 2;
 
 #if DNS_DEBUG
 
@@ -5790,7 +5792,17 @@ int dns_so_submit(struct dns_socket *so, struct dns_packet *Q, struct sockaddr *
 	if ((error = dns_so_newanswer(so, DNS_SO_MINBUF)))
 		goto syerr;
 
-	memcpy(&so->remote, host, dns_sa_len(host));
+	if (so->local.ss_family==AF_INET6 && host->sa_family==AF_INET){
+		uint32_t *addr=(uint32_t*)dns_sa_addr(AF_INET6,&so->remote);
+		/* add v4mapping*/
+		so->remote.ss_family=AF_INET6;
+		addr[0]=0;
+		addr[1]=0;
+		addr[2]=ntohl(0xffff);
+		addr[3]=((struct sockaddr_in*)host)->sin_addr.s_addr;
+		*dns_sa_port(AF_INET6,&so->remote)=((struct sockaddr_in*)host)->sin_port;
+		
+	}else memcpy(&so->remote, host, dns_sa_len(host));
 
 	so->query	= Q;
 	so->qout	= 0;
@@ -5916,31 +5928,47 @@ static int dns_so_tcp_recv(struct dns_socket *so) {
 #pragma clang diagnostic pop
 #endif
 
+#define USE_CONNECT 0
 
 int dns_so_check(struct dns_socket *so) {
 	int error;
 	long n;
+#if !USE_CONNECT
+	struct sockaddr_storage saddr;
+	socklen_t slen=sizeof(saddr);
+#endif
 
 retry:
 	switch (so->state) {
 	case DNS_SO_UDP_INIT:
 		so->state++;
 	case DNS_SO_UDP_CONN:
+#if USE_CONNECT
 		if (0 != connect(so->udp, (struct sockaddr *)&so->remote, dns_sa_len(&so->remote)))
 			goto soerr;
-
+#endif
 		so->state++;
 	case DNS_SO_UDP_SEND:
+#if USE_CONNECT
 		if (0 > (n = send(so->udp, (void *)so->query->data, so->query->end, 0)))
 			goto soerr;
-
+#else
+		if (0 > (n = sendto(so->udp, (void *)so->query->data, so->query->end, 0, (struct sockaddr *)&so->remote, dns_sa_len(&so->remote))))
+			goto soerr;
+#endif
 		so->stat.udp.sent.bytes += n;
 		so->stat.udp.sent.count++;
 
 		so->state++;
 	case DNS_SO_UDP_RECV:
+#if USE_CONNECT
 		if (0 > (n = recv(so->udp, (void *)so->answer->data, so->answer->size, 0)))
 			goto soerr;
+#else
+		if (0 > (n = recvfrom(so->udp, (void *)so->answer->data, so->answer->size, 0, (struct sockaddr*)&saddr,&slen)))
+			goto soerr;
+		/*TODO check if saddr matches one of the DNS server we previously sent a question, for security*/
+#endif
 
 		so->stat.udp.rcvd.bytes += n;
 		so->stat.udp.rcvd.count++;
@@ -6609,7 +6637,7 @@ static int dns_res_exec(struct dns_resolver *R) {
 	char host[DNS_D_MAXNAME + 1];
 	size_t len;
 	struct dns_rr rr;
-	struct sockaddr_in sin;
+	struct sockaddr_storage saddr={0};
 	int error;
 	struct dns_rr_i dns_rr_it;
 	int dns_grep_error;
@@ -6882,7 +6910,7 @@ exec:
 			goto error;
 
 		F->hints_j.name		= host;
-		F->hints_j.type		= DNS_T_A;
+		F->hints_j.type		= DNS_T_ALL;
 		F->hints_j.section	= DNS_S_ALL & ~DNS_S_QD;
 
 		if (!dns_rr_grep(&rr, 1, &F->hints_j, F->hints, &error)) {
@@ -6892,23 +6920,28 @@ exec:
 			goto(R->sp, DNS_R_FOREACH_NS);
 		}
 
-		sin.sin_family	= AF_INET;
+		saddr.ss_family	= rr.type==DNS_T_AAAA ? AF_INET6 : AF_INET;
 
-		if ((error = dns_a_parse((struct dns_a *)&sin.sin_addr, &rr, F->hints)))
-			goto error;
+		if (saddr.ss_family==AF_INET){
+			if ((error = dns_a_parse((struct dns_a *)dns_sa_addr(saddr.ss_family, &saddr), &rr, F->hints)))
+				goto error;
+		}else{
+			if ((error = dns_aaaa_parse((struct dns_aaaa *)dns_sa_addr(saddr.ss_family, &saddr), &rr, F->hints)))
+				goto error;
+		}
 
-		if (R->sp == 0)
-			sin.sin_port = dns_hints_port(R->hints, AF_INET, (struct sockaddr *)&sin.sin_addr);
-		else
-			sin.sin_port = htons(53);
+		*dns_sa_port(saddr.ss_family, &saddr) = (R->sp == 0) ? dns_hints_port(R->hints, saddr.ss_family, (struct sockaddr *)&saddr) : htons(53);
+		
 
 		if (DNS_DEBUG) {
 			char addr[INET_ADDRSTRLEN + 1];
-			dns_a_print(addr, sizeof addr, (struct dns_a *)&sin.sin_addr);
+			if (saddr.ss_family==AF_INET)
+				dns_a_print(addr, sizeof addr, (struct dns_a *)dns_sa_addr(saddr.ss_family, &saddr));
+			else dns_aaaa_print(addr, sizeof addr, (struct dns_aaaa *)dns_sa_addr(saddr.ss_family, &saddr));
 			DNS_SHOW(F->query, "ASKING: %s/%s @ DEPTH: %u)", host, addr, R->sp);
 		}
 
-		if ((error = dns_so_submit(&R->so, F->query, (struct sockaddr *)&sin)))
+		if ((error = dns_so_submit(&R->so, F->query, (struct sockaddr *)&saddr)))
 			goto error;
 
 		F->state++;

src/sipstack.c

@@ -77,6 +77,7 @@ BELLE_SIP_INSTANCIATE_VPTR(belle_sip_hop_t,belle_sip_object_t,belle_sip_hop_dest
 static void belle_sip_stack_destroy(belle_sip_stack_t *stack){
 	belle_sip_message("stack [%p] destroyed.",stack);
 	if (stack->dns_user_hosts_file) belle_sip_free(stack->dns_user_hosts_file);
+	if (stack->dns_resolv_conf) belle_sip_free(stack->dns_resolv_conf);
 	belle_sip_object_unref(stack->ml);
 }
 
@@ -197,6 +198,15 @@ void belle_sip_stack_set_dns_user_hosts_file(belle_sip_stack_t *stack, const cha
 	stack->dns_user_hosts_file = hosts_file?belle_sip_strdup(hosts_file):NULL;
 }
 
+const char * belle_sip_stack_get_dns_resolv_conf_file(const belle_sip_stack_t *stack){
+	return stack->dns_resolv_conf;
+}
+
+void belle_sip_stack_set_dns_resolv_conf_file(belle_sip_stack_t *stack, const char *resolv_conf_file){
+	if (stack->dns_resolv_conf) belle_sip_free(stack->dns_resolv_conf);
+	stack->dns_resolv_conf = resolv_conf_file?belle_sip_strdup(resolv_conf_file):NULL;
+}
+
 const char* belle_sip_version_to_string() {
 #ifdef BELLESIP_VERSION
 	return BELLESIP_VERSION;

tester/belle_sip_resolver_tester.c

@@ -407,7 +407,120 @@ static void no_query_needed(void) {
 	destroy_endpoint(client);
 }
 
+static void set_custom_resolv_conf(belle_sip_stack_t *stack, const char *ns[3]){
+	FILE *f=fopen("tmp_resolv.conf","w");
+	CU_ASSERT_PTR_NOT_NULL(f);
+	if (f){
+		int i;
+		for (i=0; i<3; ++i){
+			if (ns[i]!=NULL){
+				fprintf(f,"nameserver %s\n",ns[i]);
+			}
+		}
+		fclose(f);
+	}
+	belle_sip_stack_set_dns_resolv_conf_file(stack,"tmp_resolv.conf");
+}
+
+static void dns_fallback(void) {
+	struct addrinfo *ai;
+	int timeout;
+	endpoint_t *client = create_endpoint();
+	const char *nameservers[]={
+		"94.23.19.176", /*linphone.org ; this is not a name server, it will not respond*/
+		"8.8.8.8", /* public nameserver, should work*/
+		NULL
+	};
+
+	CU_ASSERT_PTR_NOT_NULL_FATAL(client);
+	timeout = belle_sip_stack_get_dns_timeout(client->stack);
+	set_custom_resolv_conf(client->stack,nameservers);
+	client->resolver_ctx = belle_sip_stack_resolve_a(client->stack, IPV4_SIP_DOMAIN, SIP_PORT, AF_INET, a_resolve_done, client);
+	CU_ASSERT_NOT_EQUAL(client->resolver_ctx, NULL);
+	CU_ASSERT_TRUE(wait_for(client->stack, &client->resolve_done, 1, timeout));
+	CU_ASSERT_PTR_NOT_EQUAL(client->ai_list, NULL);
+	if (client->ai_list) {
+		struct sockaddr_in *sock_in = (struct sockaddr_in *)client->ai_list->ai_addr;
+		CU_ASSERT_EQUAL(ntohs(sock_in->sin_port), SIP_PORT);
+		ai = belle_sip_ip_address_to_addrinfo(AF_INET, IPV4_SIP_IP, SIP_PORT);
+		if (ai) {
+			CU_ASSERT_EQUAL(sock_in->sin_addr.s_addr, ((struct sockaddr_in *)ai->ai_addr)->sin_addr.s_addr);
+			freeaddrinfo(ai);
+		}
+	}
+
+	destroy_endpoint(client);
+}
+
+static void ipv6_dns_server(void) {
+	struct addrinfo *ai;
+	int timeout;
+	endpoint_t *client;
+	const char *nameservers[]={
+		"2a01:e00::2",
+		NULL
+	};
+	
+	if (!belle_sip_tester_ipv6_available()){
+		belle_sip_warning("Test skipped, IPv6 connectivity not available.");
+		return;
+	}
+	
+	client = create_endpoint();
+	CU_ASSERT_PTR_NOT_NULL_FATAL(client);
+	timeout = belle_sip_stack_get_dns_timeout(client->stack);
+	set_custom_resolv_conf(client->stack,nameservers);
+	client->resolver_ctx = belle_sip_stack_resolve_a(client->stack, IPV4_SIP_DOMAIN, SIP_PORT, AF_INET, a_resolve_done, client);
+	CU_ASSERT_NOT_EQUAL(client->resolver_ctx, NULL);
+	CU_ASSERT_TRUE(wait_for(client->stack, &client->resolve_done, 1, timeout));
+	CU_ASSERT_PTR_NOT_EQUAL(client->ai_list, NULL);
+	if (client->ai_list) {
+		struct sockaddr_in *sock_in = (struct sockaddr_in *)client->ai_list->ai_addr;
+		CU_ASSERT_EQUAL(ntohs(sock_in->sin_port), SIP_PORT);
+		ai = belle_sip_ip_address_to_addrinfo(AF_INET, IPV4_SIP_IP, SIP_PORT);
+		if (ai) {
+			CU_ASSERT_EQUAL(sock_in->sin_addr.s_addr, ((struct sockaddr_in *)ai->ai_addr)->sin_addr.s_addr);
+			freeaddrinfo(ai);
+		}
+	}
+
+	destroy_endpoint(client);
+}
 
+static void ipv4_and_ipv6_dns_server(void) {
+	struct addrinfo *ai;
+	int timeout;
+	endpoint_t *client;
+	const char *nameservers[]={
+		"8.8.8.8",
+		"2a01:e00::2",
+		NULL
+	};
+	
+	if (!belle_sip_tester_ipv6_available()){
+		belle_sip_warning("Test skipped, IPv6 connectivity not available.");
+		return;
+	}
+	client = create_endpoint();
+	CU_ASSERT_PTR_NOT_NULL_FATAL(client);
+	timeout = belle_sip_stack_get_dns_timeout(client->stack);
+	set_custom_resolv_conf(client->stack,nameservers);
+	client->resolver_ctx = belle_sip_stack_resolve_a(client->stack, IPV4_SIP_DOMAIN, SIP_PORT, AF_INET, a_resolve_done, client);
+	CU_ASSERT_NOT_EQUAL(client->resolver_ctx, NULL);
+	CU_ASSERT_TRUE(wait_for(client->stack, &client->resolve_done, 1, timeout));
+	CU_ASSERT_PTR_NOT_EQUAL(client->ai_list, NULL);
+	if (client->ai_list) {
+		struct sockaddr_in *sock_in = (struct sockaddr_in *)client->ai_list->ai_addr;
+		CU_ASSERT_EQUAL(ntohs(sock_in->sin_port), SIP_PORT);
+		ai = belle_sip_ip_address_to_addrinfo(AF_INET, IPV4_SIP_IP, SIP_PORT);
+		if (ai) {
+			CU_ASSERT_EQUAL(sock_in->sin_addr.s_addr, ((struct sockaddr_in *)ai->ai_addr)->sin_addr.s_addr);
+			freeaddrinfo(ai);
+		}
+	}
+
+	destroy_endpoint(client);
+}
 
 test_t resolver_tests[] = {
 	{ "A query (IPv4)", ipv4_a_query },
@@ -424,6 +537,9 @@ test_t resolver_tests[] = {
 	{ "SRV + A query with no SRV result", srv_a_query_no_srv_result },
 	{ "Local SRV+A query", local_full_query },
 	{ "No query needed", no_query_needed },
+	{ "DNS fallback", dns_fallback },
+	{ "IPv6 DNS server", ipv6_dns_server },
+	{ "IPv4 and v6 DNS servers", ipv4_and_ipv6_dns_server }
 };
 
 test_suite_t resolver_test_suite = {

tester/belle_sip_tester.c

@@ -99,8 +99,33 @@ const char * belle_sip_tester_test_name(const char *suite_name, int test_index)
 	return test_suite[suite_index]->tests[test_index].name;
 }
 
+static int _belle_sip_tester_ipv6_available(void){
+	struct addrinfo *ai=belle_sip_ip_address_to_addrinfo(AF_INET6,"2a01:e00::2",53);
+	if (ai){
+		struct sockaddr_storage ss;
+		struct addrinfo src;
+		socklen_t slen=sizeof(ss);
+		char localip[128];
+		int port=0;
+		belle_sip_get_src_addr_for(ai->ai_addr,ai->ai_addrlen,(struct sockaddr*) &ss,&slen,4444);
+		src.ai_addr=(struct sockaddr*) &ss;
+		src.ai_addrlen=slen;
+		belle_sip_addrinfo_to_ip(&src,localip, sizeof(localip),&port);
+		freeaddrinfo(ai);
+		return strcmp(localip,"::1")!=0;
+	}
+	return FALSE;
+}
+
+static int ipv6_available=0;
+
+int belle_sip_tester_ipv6_available(void){
+	return ipv6_available;
+}
+
 void belle_sip_tester_init(void) {
 	belle_sip_object_enable_marshal_check(TRUE);
+	ipv6_available=_belle_sip_tester_ipv6_available();
 	add_test_suite(&cast_test_suite);
 	add_test_suite(&uri_test_suite);
 	add_test_suite(&headers_test_suite);
@@ -114,6 +139,8 @@ void belle_sip_tester_init(void) {
 	add_test_suite(&refresher_test_suite);
 }
 
+
+
 void belle_sip_tester_uninit(void) {
 	if (test_suite != NULL) {
 		free(test_suite);

tester/belle_sip_tester.h

@@ -56,7 +56,7 @@ extern test_suite_t register_test_suite;
 extern test_suite_t dialog_test_suite;
 extern test_suite_t refresher_test_suite;
 
-
+extern int belle_sip_tester_ipv6_available(void);
 extern int belle_sip_tester_nb_test_suites(void);
 extern int belle_sip_tester_nb_tests(const char *suite_name);
 extern const char * belle_sip_tester_test_suite_name(int suite_index);