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ADD EDNS check feature, TCP server bugfix

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This commit is contained in:
Nick Peng
2018-12-20 00:16:32 +08:00
parent 3d8155e67b
commit 40740f531b
8 changed files with 230 additions and 52 deletions
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8
etc/smartdns/smartdns.conf
View File

@@ -66,17 +66,17 @@ log-level info
# audit-num 2
# remote udp dns server list
# server [IP]:[PORT] [-blacklist-ip]
# server [IP]:[PORT] [-blacklist-ip] [-check-edns]
# default port is 53
# server 8.8.8.8 -blacklist-ip
# server 8.8.8.8 -blacklist-ip -check-edns
# remote tcp dns server list
# server-tcp [IP]:[PORT] [-blacklist-ip]
# server-tcp [IP]:[PORT] [-blacklist-ip] [-check-edns]
# default port is 53
# server-tcp 8.8.8.8
# remote tls dns server list
# server-tls [IP]:[PORT] [-blacklist-ip]
# server-tls [IP]:[PORT] [-blacklist-ip] [-check-edns]
# default port is 853
# server-tls 8.8.8.8
# server-tls 1.0.0.1

175
src/dns.c
View File

@@ -184,6 +184,9 @@ int dns_rr_add_end(struct dns_packet *packet, int type, dns_type_t rtype, int le
count = &head->nrcount;
start = &packet->additional;
break;
case DNS_RRS_OPT:
count = &packet->optcount;
start = &packet->optional;
default:
return -1;
break;
@@ -638,10 +641,23 @@ int dns_get_SOA(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, struct
return 0;
}
int dns_set_OPT_payload_size(struct dns_packet *packet, int payload_size)
{
if (payload_size < 512) {
payload_size = 512;
}
packet->payloadsize = payload_size;
return 0;
}
int dns_get_OPT_payload_size(struct dns_packet *packet)
{
return packet->payloadsize;
}
int dns_add_OPT_ECS(struct dns_packet *packet, dns_rr_type type, struct dns_opt_ecs *ecs)
{
// TODO
unsigned char opt_data[DNS_MAX_OPT_LEN];
struct dns_opt *opt = (struct dns_opt *)opt_data;
int len = 0;
@@ -655,18 +671,21 @@ int dns_add_OPT_ECS(struct dns_packet *packet, dns_rr_type type, struct dns_opt_
len += (ecs->source_prefix / 8);
len += (ecs->source_prefix % 8 > 0) ? 1 : 0;
return dns_add_OPT(packet, type, DNS_OPT_T_ECS, len, opt);
return dns_add_RAW(packet, DNS_RRS_OPT, DNS_OPT_T_ECS, "", 0, opt_data, len);
}
int dns_get_OPT_ECS(struct dns_rrs *rrs, unsigned short *opt_code, unsigned short *opt_len, struct dns_opt_ecs *ecs)
{
// TODO
unsigned char opt_data[DNS_MAX_OPT_LEN];
struct dns_opt *opt = (struct dns_opt *)opt_data;
int len = sizeof(opt_data);
int len = DNS_MAX_OPT_LEN;
int ttl = 0;
if (dns_get_OPT(rrs, opt_code, opt_len, opt, &len) != 0) {
if (dns_get_RAW(rrs, 0, 0, &ttl, opt_data, &len) != 0) {
return -1;
}
if (len < sizeof(*opt)) {
return -1;
}
@@ -801,6 +820,20 @@ static int _dns_encode_head(struct dns_context *context)
return len;
}
static int _dns_encode_head_count(struct dns_context *context)
{
int len = 12;
struct dns_head *head = &context->packet->head;
unsigned char *ptr = context->data;
ptr += 4;
dns_write_short(&ptr, head->qdcount);
dns_write_short(&ptr, head->ancount);
dns_write_short(&ptr, head->nscount);
dns_write_short(&ptr, head->nrcount);
return len;
}
static int _dns_decode_domain(struct dns_context *context, char *output, int size)
{
int output_len = 0;
@@ -880,7 +913,6 @@ static int _dns_decode_domain(struct dns_context *context, char *output, int siz
static int _dns_encode_domain(struct dns_context *context, char *domain)
{
int num = 0;
int total_len = 0;
unsigned char *ptr_num = context->ptr++;
/*[len]string[len]string...[0]0 */
@@ -897,15 +929,12 @@ static int _dns_encode_domain(struct dns_context *context, char *domain)
num++;
context->ptr++;
domain++;
total_len++;
}
*ptr_num = num;
if (total_len > 0) {
/* if domain is '\0', [domain] is '\0' */
*(context->ptr) = 0;
context->ptr++;
}
/* if domain is '\0', [domain] is '\0' */
*(context->ptr) = 0;
context->ptr++;
return 0;
}
@@ -1238,8 +1267,97 @@ static int _dns_decode_opt_ecs(struct dns_context *context, struct dns_opt_ecs *
int _dns_encode_OPT(struct dns_context *context, struct dns_rrs *rrs)
{
// TODO
int ret;
int opt_code = 0;
int qclass = 0;
char domain[DNS_MAX_CNAME_LEN];
struct dns_data_context data_context;
int rr_len = 0;
int ttl;
data_context.data = rrs->data;
data_context.ptr = rrs->data;
data_context.maxsize = rrs->len;
ret = _dns_get_rr_head(&data_context, domain, DNS_MAX_CNAME_LEN, &opt_code, &qclass, &ttl, &rr_len);
if (ret < 0) {
return -1;
}
if (_dns_left_len(context) < (4 + rr_len)) {
return -1;
}
dns_write_short(&context->ptr, opt_code);
dns_write_short(&context->ptr, rr_len);
memcpy(context->ptr, data_context.ptr, rr_len);
context->ptr += rr_len;
return 0;
}
int _dns_get_opts_data_len(struct dns_packet *packet, struct dns_rrs *rrs, int count)
{
int i = 0;
int len = 0;
int opt_code = 0;
int qclass = 0;
int ttl;
int ret;
char domain[DNS_MAX_CNAME_LEN];
struct dns_data_context data_context;
int rr_len = 0;
for (i = 0; i < count && rrs; i++, rrs = dns_get_rrs_next(packet, rrs)) {
data_context.data = rrs->data;
data_context.ptr = rrs->data;
data_context.maxsize = rrs->len;
ret = _dns_get_rr_head(&data_context, domain, DNS_MAX_CNAME_LEN, &opt_code, &qclass, &ttl, &rr_len);
if (ret < 0) {
return -1;
}
len += rr_len;
}
return len;
}
int _dns_encode_opts(struct dns_packet *packet, struct dns_context *context, struct dns_rrs *rrs, int count)
{
int i = 0;
int len = 0;
int ret = 0;
unsigned int rcode = 0;
int rr_len = 0;
int payloadsize = packet->payloadsize;
rr_len = _dns_get_opts_data_len(packet, rrs, count);
if (rr_len < 0) {
return -1;
}
if (payloadsize < DNS_DEFAULT_PACKET_SIZE) {
payloadsize = DNS_DEFAULT_PACKET_SIZE;
}
ret = _dns_encode_rr_head(context, "0", DNS_T_OPT, payloadsize, rcode, rr_len);
if (ret < 0) {
return -1;
}
if (_dns_left_len(context) < rr_len) {
return -1;
}
for (i = 0; i < count && rrs; i++, rrs = dns_get_rrs_next(packet, rrs)) {
len = _dns_encode_OPT(context, rrs);
if (len < 0) {
return -1;
}
}
return 0;
}
@@ -1453,6 +1571,8 @@ static int _dns_decode_an(struct dns_context *context, dns_rr_type type)
tlog(TLOG_ERROR, "opt length mitchmatch, %s\n", domain);
return -1;
}
dns_set_OPT_payload_size(packet, qclass);
} break;
default:
context->ptr += rr_len;
@@ -1517,12 +1637,6 @@ static int _dns_encode_an(struct dns_context *context, struct dns_rrs *rrs)
return -1;
}
break;
case DNS_T_OPT:
ret = _dns_encode_OPT(context, rrs);
if (ret < 0) {
return -1;
}
break;
default:
break;
}
@@ -1621,6 +1735,15 @@ static int _dns_encode_body(struct dns_context *context)
}
}
rrs = dns_get_rrs_start(packet, DNS_RRS_OPT, &count);
if (count > 0 || packet->payloadsize > 0) {
len = _dns_encode_opts(packet, context, rrs, count);
if (len < 0) {
return -1;
}
head->nrcount++;
}
return 0;
}
@@ -1641,6 +1764,9 @@ int dns_packet_init(struct dns_packet *packet, int size, struct dns_head *head)
packet->answers = DNS_RR_END;
packet->nameservers = DNS_RR_END;
packet->additional = DNS_RR_END;
packet->optional = DNS_RR_END;
packet->optcount = 0;
packet->payloadsize = 0;
return 0;
}
@@ -1695,6 +1821,11 @@ int dns_encode(unsigned char *data, int size, struct dns_packet *packet)
return -1;
}
ret = _dns_encode_head_count(&context);
if (ret < 0) {
return -1;
}
return context.ptr - context.data;
}

11
src/dns.h
View File

@@ -12,6 +12,7 @@
#define DNS_MAX_OPT_LEN 256
#define DNS_IN_PACKSIZE (512 * 4)
#define DNS_PACKSIZE (512 * 8)
#define DNS_DEFAULT_PACKET_SIZE 512
typedef enum dns_qr {
DNS_QR_QUERY = 0,
@@ -23,7 +24,8 @@ typedef enum dns_rr_type {
DNS_RRS_AN = 1,
DNS_RRS_NS = 2,
DNS_RRS_NR = 3,
DNS_RRS_END = 4,
DNS_RRS_OPT = 4,
DNS_RRS_END,
} dns_rr_type;
typedef enum dns_class { DNS_C_IN = 1, DNS_C_ANY = 255 } dns_class_t;
@@ -104,6 +106,9 @@ struct dns_packet {
unsigned short answers;
unsigned short nameservers;
unsigned short additional;
unsigned short optcount;
unsigned short optional;
unsigned short payloadsize;
int size;
int len;
unsigned char data[0];
@@ -180,8 +185,8 @@ int dns_get_AAAA(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, unsig
int dns_add_SOA(struct dns_packet *packet, dns_rr_type type, char *domain, int ttl, struct dns_soa *soa);
int dns_get_SOA(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, struct dns_soa *soa);
int dns_add_OPT(struct dns_packet *packet, dns_rr_type type, unsigned short opt_code, unsigned short opt_len, struct dns_opt *opt);
int dns_get_OPT(struct dns_rrs *rrs, unsigned short *opt_code, unsigned short *opt_len, struct dns_opt *opt, int *opt_maxlen);
int dns_set_OPT_payload_size(struct dns_packet *packet, int payload_size);
int dns_get_OPT_payload_size(struct dns_packet *packet);
int dns_add_OPT_ECS(struct dns_packet *packet, dns_rr_type type, struct dns_opt_ecs *ecs);
int dns_get_OPT_ECS(struct dns_rrs *rrs, unsigned short *opt_code, unsigned short *opt_len, struct dns_opt_ecs *ecs);

28
src/dns_client.c
View File

@@ -48,7 +48,7 @@
#define DNS_MAX_HOSTNAME 256
#define DNS_MAX_EVENTS 64
#define DNS_HOSTNAME_LEN 128
#define DNS_TCP_BUFFER (8 * 1024)
#define DNS_TCP_BUFFER (16 * 1024)
/* dns client */
struct dns_client {
@@ -602,6 +602,7 @@ static int _dns_client_recv(struct dns_server_info *server_info, unsigned char *
int ret = 0;
struct dns_query_struct *query;
int request_num = 0;
int has_opt = 0;
packet->head.tc = 0;
@@ -620,9 +621,9 @@ static int _dns_client_recv(struct dns_server_info *server_info, unsigned char *
return -1;
}
tlog(TLOG_DEBUG, "qdcount = %d, ancount = %d, nscount = %d, nrcount = %d, len = %d, id = %d, tc = %d, rd = %d, ra = %d, rcode = %d\n", packet->head.qdcount,
tlog(TLOG_DEBUG, "qdcount = %d, ancount = %d, nscount = %d, nrcount = %d, len = %d, id = %d, tc = %d, rd = %d, ra = %d, rcode = %d, payloadsize = %d\n", packet->head.qdcount,
packet->head.ancount, packet->head.nscount, packet->head.nrcount, inpacket_len, packet->head.id, packet->head.tc, packet->head.rd, packet->head.ra,
packet->head.rcode);
packet->head.rcode, dns_get_OPT_payload_size(packet));
/* get question */
rrs = dns_get_rrs_start(packet, DNS_RRS_QD, &rr_count);
@@ -631,9 +632,13 @@ static int _dns_client_recv(struct dns_server_info *server_info, unsigned char *
tlog(TLOG_DEBUG, "domain: %s qtype: %d qclass: %d\n", domain, qtype, qclass);
}
if (dns_get_OPT_payload_size(packet) > 0) {
has_opt = 1;
}
/* get query reference */
query = _dns_client_get_request(packet->head.id, domain);
if (query == NULL) {
if (query == NULL || (query && has_opt == 0 && server_info->result_flag & DNSSERVER_FLAG_CHECK_EDNS)) {
return 0;
}
@@ -813,6 +818,10 @@ static int _dns_client_create_socket(struct dns_server_info *server_info)
time(&server_info->last_send);
time(&server_info->last_recv);
if (server_info->fd > 0) {
return -1;
}
if (server_info->type == DNS_SERVER_UDP) {
return _dns_client_create_socket_udp(server_info);
} else if (server_info->type == DNS_SERVER_TCP) {
@@ -1372,6 +1381,11 @@ static void *_dns_client_work(void *arg)
for (i = 0; i < num; i++) {
struct epoll_event *event = &events[i];
struct dns_server_info *server_info = (struct dns_server_info *)event->data.ptr;
if (server_info == NULL) {
tlog(TLOG_WARN, "server info is invalid.");
continue;
}
_dns_client_process(server_info, event, now);
}
}
@@ -1398,6 +1412,7 @@ static int _dns_client_send_data_to_buffer(struct dns_server_info *server_info,
struct epoll_event event;
if (DNS_TCP_BUFFER - server_info->send_buff.len < len) {
errno = ENOMEM;
return -1;
}
@@ -1434,6 +1449,10 @@ static int _dns_client_send_tcp(struct dns_server_info *server_info, void *packe
/* save data to buffer, and retry when EPOLLOUT is available */
return _dns_client_send_data_to_buffer(server_info, inpacket, len);
}
if (errno == EPIPE) {
shutdown(server_info->fd, SHUT_RDWR);
}
return -1;
} else if (send_len < len) {
/* save remain data to buffer, and retry when EPOLLOUT is available */
@@ -1552,6 +1571,7 @@ static int _dns_client_send_query(struct dns_query_struct *query, char *doamin)
/* add question */
dns_add_domain(packet, doamin, query->qtype, DNS_C_IN);
dns_set_OPT_payload_size(packet, 1024);
/* encode packet */
encode_len = dns_encode(inpacket, DNS_IN_PACKSIZE, packet);
if (encode_len <= 0) {

1
src/dns_client.h
View File

@@ -17,6 +17,7 @@ typedef enum dns_result_type {
} dns_result_type;
#define DNSSERVER_FLAG_BLACKLIST_IP (0x1 << 0)
#define DNSSERVER_FLAG_CHECK_EDNS (0x1 << 1)
int dns_client_init(void);

5
src/dns_conf.c
View File

@@ -52,6 +52,7 @@ int config_server(int argc, char *argv[], dns_server_type_t type, int default_po
/* clang-format off */
static struct option long_options[] = {
{"blacklist-ip", 0, 0, 'b'},
{"check-edns", 0, 0, 'e'},
{0, 0, 0, 0}
};
/* clang-format on */
@@ -73,6 +74,10 @@ int config_server(int argc, char *argv[], dns_server_type_t type, int default_po
result_flag |= DNSSERVER_FLAG_BLACKLIST_IP;
break;
}
case 'e': {
result_flag |= DNSSERVER_FLAG_CHECK_EDNS;
break;
}
}
}

10
src/dns_server.c
View File

@@ -551,6 +551,7 @@ void _dns_server_request_release(struct dns_request *request)
free(addr_map);
}
pthread_mutex_destroy(&request->ip_map_lock);
_dns_server_client_release(request->client);
memset(request, 0, sizeof(*request));
free(request);
}
@@ -903,7 +904,6 @@ static int dns_server_resolve_callback(char *domain, dns_result_type rtype, unsi
void *user_ptr)
{
struct dns_request *request = user_ptr;
struct dns_server_conn *client = request->client;
int ip_num = 0;
if (request == NULL) {
@@ -936,7 +936,6 @@ static int dns_server_resolve_callback(char *domain, dns_result_type rtype, unsi
_dns_server_request_remove(request);
}
_dns_server_request_release(request);
_dns_server_client_release(client);
}
return 0;
@@ -1944,6 +1943,13 @@ errout:
void _dns_server_close_socket(void)
{
struct dns_server_conn *client, *tmp;
list_for_each_entry_safe(client, tmp, &server.client_list, list)
{
_dns_server_client_close(client);
}
if (server.udp_server.fd > 0) {
close(server.udp_server.fd);
server.udp_server.fd = 0;

44
src/smartdns.c
View File

@@ -272,21 +272,36 @@ void smartdns_exit(void)
dns_server_load_exit();
}
void sig_handle(int sig)
void sig_exit(int signo)
{
switch (sig) {
case SIGINT:
dns_server_stop();
return;
break;
default:
break;
}
tlog(TLOG_ERROR, "process exit with signal %d\n", sig);
dns_server_stop();
}
void sig_error_exit(int signo, siginfo_t *siginfo, void *context)
{
tlog(TLOG_ERROR, "process exit with signal %d, code = %d, errno = %d, pid = %d, self = %d, addr = %p\n", signo,
siginfo->si_code, siginfo->si_errno, siginfo->si_pid, getpid(), siginfo->si_addr);
sleep(1);
_exit(0);
}
int sig_list[] = {SIGSEGV, SIGABRT, SIGPIPE, SIGBUS, SIGILL, SIGFPE};
int sig_num = sizeof(sig_list) / sizeof(int);
void reg_signal(void)
{
struct sigaction act, old;
int i = 0;
act.sa_sigaction = sig_error_exit;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_RESTART | SA_SIGINFO;
for (i = 0; i < sig_num; i++) {
sigaction(sig_list[i], &act, &old);
}
}
int main(int argc, char *argv[])
{
int ret;
@@ -330,12 +345,7 @@ int main(int argc, char *argv[])
}
if (signal_ignore == 0) {
signal(SIGABRT, sig_handle);
signal(SIGPIPE, SIG_IGN);
signal(SIGBUS, sig_handle);
signal(SIGSEGV, sig_handle);
signal(SIGILL, sig_handle);
signal(SIGFPE, sig_handle);
reg_signal();
}
if (dns_server_load_conf(config_file) != 0) {
@@ -351,7 +361,7 @@ int main(int argc, char *argv[])
goto errout;
}
signal(SIGINT, sig_handle);
signal(SIGINT, sig_exit);
atexit(smartdns_exit);
return smartdns_run();