dns_server: fix edns subnet not working issue.

src/dns.c

@@ -875,6 +875,22 @@ int dns_get_PTR(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, char *
 	return _dns_get_RAW(rrs, domain, maxsize, ttl, cname, &len);
 }
 
+int dns_add_TXT(struct dns_packet *packet, dns_rr_type type, const char *domain, int ttl, const char *text)
+{
+	int rr_len = strnlen(text, DNS_MAX_CNAME_LEN);
+	char data[DNS_MAX_CNAME_LEN];
+	data[0] = rr_len;
+	rr_len++;
+	memcpy(data + 1, text, rr_len);
+	data[rr_len] = 0;
+	return _dns_add_RAW(packet, type, DNS_T_TXT, domain, ttl, data, rr_len);
+}
+
+int dns_get_TXT(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, char *text, int txt_size)
+{
+	return -1;
+}
+
 int dns_add_NS(struct dns_packet *packet, dns_rr_type type, const char *domain, int ttl, const char *cname)
 {
 	int rr_len = strnlen(cname, DNS_MAX_CNAME_LEN) + 1;

src/dns.h

@@ -262,6 +262,9 @@ int dns_get_A(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, unsigned
 int dns_add_PTR(struct dns_packet *packet, dns_rr_type type, const char *domain, int ttl, const char *cname);
 int dns_get_PTR(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, char *cname, int cname_size);
 
+int dns_add_TXT(struct dns_packet *packet, dns_rr_type type, const char *domain, int ttl, const char *text);
+int dns_get_TXT(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, char *text, int txt_size);
+
 int dns_add_AAAA(struct dns_packet *packet, dns_rr_type type, const char *domain, int ttl,
 				 unsigned char addr[DNS_RR_AAAA_LEN]);
 int dns_get_AAAA(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, unsigned char addr[DNS_RR_AAAA_LEN]);

src/dns_client.c

@@ -3378,16 +3378,7 @@ static int _dns_client_setup_server_packet(struct dns_server_info *server_info,
 	*packet_data = default_packet;
 	*packet_data_len = default_packet_len;
 
-	if (query->qtype != DNS_T_AAAA && query->qtype != DNS_T_A) {
+	if (server_info->ecs_ipv4.enable == true || server_info->ecs_ipv6.enable == true) {
-		/* no need to encode packet */
-		return 0;
-	}
-
-	if (server_info->ecs_ipv4.enable == true && query->qtype == DNS_T_A) {
-		repack = 1;
-	}
-
-	if (server_info->ecs_ipv6.enable == true && query->qtype == DNS_T_AAAA) {
 		repack = 1;
 	}
 
@@ -3429,12 +3420,16 @@ static int _dns_client_setup_server_packet(struct dns_server_info *server_info,
 
 	dns_set_OPT_payload_size(packet, DNS_IN_PACKSIZE);
 	/* dns_add_OPT_TCP_KEEPALIVE(packet, 600); */
-	if ((query->qtype == DNS_T_A && server_info->ecs_ipv4.enable) ||
+	if ((query->qtype == DNS_T_A && server_info->ecs_ipv4.enable)) {
-		(query->qtype == DNS_T_AAAA && server_info->ecs_ipv6.enable == 0 && server_info->ecs_ipv4.enable)) {
 		dns_add_OPT_ECS(packet, &server_info->ecs_ipv4.ecs);
-	} else if ((query->qtype == DNS_T_AAAA && server_info->ecs_ipv6.enable) ||
+	} else if ((query->qtype == DNS_T_AAAA && server_info->ecs_ipv6.enable)) {
-			   (query->qtype == DNS_T_A && server_info->ecs_ipv4.enable == 0 && server_info->ecs_ipv6.enable)) {
 		dns_add_OPT_ECS(packet, &server_info->ecs_ipv6.ecs);
+	} else {
+		if (server_info->ecs_ipv6.enable) {
+			dns_add_OPT_ECS(packet, &server_info->ecs_ipv6.ecs);
+		} else if (server_info->ecs_ipv4.enable) {
+			dns_add_OPT_ECS(packet, &server_info->ecs_ipv4.ecs);
+		}
 	}
 
 	/* encode packet */
@@ -3671,20 +3666,20 @@ static int _dns_client_query_setup_default_ecs(struct dns_query_struct *query)
 		if (client.ecs_ipv4.enable) {
 			add_ipv4_ecs = 1;
 		} else if (client.ecs_ipv6.enable) {
-			add_ipv4_ecs = 1;
+			add_ipv6_ecs = 1;
 		}
 	}
 
-	if (add_ipv4_ecs) {
-		memcpy(&query->ecs, &client.ecs_ipv4, sizeof(query->ecs));
-		return 0;
-	}
-
 	if (add_ipv6_ecs) {
 		memcpy(&query->ecs, &client.ecs_ipv6, sizeof(query->ecs));
 		return 0;
 	}
 
+	if (add_ipv4_ecs) {
+		memcpy(&query->ecs, &client.ecs_ipv4, sizeof(query->ecs));
+		return 0;
+	}
+
 	return 0;
 }
 

test/cases/test-subnet.cc

@@ -245,6 +245,148 @@ cache-persist no)""");
 	EXPECT_EQ(client.GetAnswer()[0].GetData(), "2001:db8::1");
 }
 
+TEST_F(SubNet, v4_server_subnet_txt)
+{
+	smartdns::MockServer server_upstream;
+	smartdns::Server server;
+
+	server_upstream.Start("udp://0.0.0.0:61053", [&](struct smartdns::ServerRequestContext *request) {
+		if (request->qtype != DNS_T_TXT) {
+			return smartdns::SERVER_REQUEST_SOA;
+		}
+		struct dns_opt_ecs ecs;
+		struct dns_rrs *rrs = NULL;
+		int rr_count = 0;
+		int i = 0;
+		int ret = 0;
+		int has_ecs = 0;
+
+		rr_count = 0;
+		rrs = dns_get_rrs_start(request->packet, DNS_RRS_OPT, &rr_count);
+		if (rr_count <= 0) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		for (i = 0; i < rr_count && rrs; i++, rrs = dns_get_rrs_next(request->packet, rrs)) {
+			memset(&ecs, 0, sizeof(ecs));
+			ret = dns_get_OPT_ECS(rrs, NULL, NULL, &ecs);
+			if (ret != 0) {
+				continue;
+			}
+			has_ecs = 1;
+			break;
+		}
+
+		if (has_ecs == 0) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		if (ecs.family != DNS_OPT_ECS_FAMILY_IPV4) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		if (memcmp(ecs.addr, "\x08\x08\x08\x00", 4) != 0) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		if (ecs.source_prefix != 24) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		dns_add_TXT(request->response_packet, DNS_RRS_AN, request->domain.c_str(), 6, "hello world");
+		return smartdns::SERVER_REQUEST_OK;
+	});
+
+	server.Start(R"""(bind [::]:60053
+server 127.0.0.1:61053 -subnet 8.8.8.8/24
+log-num 0
+log-console yes
+dualstack-ip-selection no
+log-level debug
+rr-ttl-min 0
+cache-persist no)""");
+	smartdns::Client client;
+	ASSERT_TRUE(client.Query("a.com TXT", 60053));
+	std::cout << client.GetResult() << std::endl;
+	ASSERT_EQ(client.GetAnswerNum(), 1);
+	EXPECT_EQ(client.GetStatus(), "NOERROR");
+	EXPECT_EQ(client.GetAnswer()[0].GetName(), "a.com");
+	EXPECT_EQ(client.GetAnswer()[0].GetTTL(), 6);
+	EXPECT_EQ(client.GetAnswer()[0].GetType(), "TXT");
+	EXPECT_EQ(client.GetAnswer()[0].GetData(), "\"hello world\"");
+}
+
+TEST_F(SubNet, v6_default_subnet_txt)
+{
+	smartdns::MockServer server_upstream;
+	smartdns::Server server;
+
+	server_upstream.Start("udp://0.0.0.0:61053", [&](struct smartdns::ServerRequestContext *request) {
+		if (request->qtype != DNS_T_TXT) {
+			return smartdns::SERVER_REQUEST_SOA;
+		}
+		struct dns_opt_ecs ecs;
+		struct dns_rrs *rrs = NULL;
+		int rr_count = 0;
+		int i = 0;
+		int ret = 0;
+		int has_ecs = 0;
+
+		rr_count = 0;
+		rrs = dns_get_rrs_start(request->packet, DNS_RRS_OPT, &rr_count);
+		if (rr_count <= 0) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		for (i = 0; i < rr_count && rrs; i++, rrs = dns_get_rrs_next(request->packet, rrs)) {
+			memset(&ecs, 0, sizeof(ecs));
+			ret = dns_get_OPT_ECS(rrs, NULL, NULL, &ecs);
+			if (ret != 0) {
+				continue;
+			}
+			has_ecs = 1;
+			break;
+		}
+		if (has_ecs == 0) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		if (ecs.family != DNS_OPT_ECS_FAMILY_IPV6) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		if (memcmp(ecs.addr, "\xff\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00", 16) != 0) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		if (ecs.source_prefix != 64) {
+			return smartdns::SERVER_REQUEST_ERROR;
+		}
+
+		dns_add_TXT(request->response_packet, DNS_RRS_AN, request->domain.c_str(), 6, "hello world");
+		return smartdns::SERVER_REQUEST_OK;
+	});
+
+	server.Start(R"""(bind [::]:60053
+server 127.0.0.1:61053
+log-num 0
+log-console yes
+dualstack-ip-selection no
+rr-ttl-min 0
+edns-client-subnet ffff:ffff:ffff:ffff:ffff::/64
+log-level debug
+cache-persist no)""");
+	smartdns::Client client;
+	ASSERT_TRUE(client.Query("a.com TXT", 60053));
+	std::cout << client.GetResult() << std::endl;
+	ASSERT_EQ(client.GetAnswerNum(), 1);
+	EXPECT_EQ(client.GetStatus(), "NOERROR");
+	EXPECT_EQ(client.GetAnswer()[0].GetName(), "a.com");
+	EXPECT_EQ(client.GetAnswer()[0].GetTTL(), 6);
+	EXPECT_EQ(client.GetAnswer()[0].GetType(), "TXT");
+	EXPECT_EQ(client.GetAnswer()[0].GetData(), "\"hello world\"");
+}
+
 TEST_F(SubNet, per_server)
 {
 	smartdns::MockServer server_upstream1;