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Receive DNS packet with IP-TTL.

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This commit is contained in:
Nick Peng
2018-12-22 23:52:53 +08:00
parent 1edb286a82
commit 11552f906f
9 changed files with 158 additions and 38 deletions
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84
src/dns_client.c
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@@ -109,6 +109,7 @@ struct dns_server_info {
/* client socket */
int fd;
int ttl;
SSL *ssl;
SSL_CTX *ssl_ctx;
dns_server_status status;
@@ -225,8 +226,21 @@ int _dns_client_server_exist(struct addrinfo *gai, dns_server_type_t server_type
return -1;
}
void _dns_client_server_update_ttl(struct ping_host_struct *ping_host, const char *host, FAST_PING_RESULT result, struct sockaddr *addr, socklen_t addr_len, int seqno,
int ttl, struct timeval *tv, void *userptr)
{
struct dns_server_info *server_info = userptr;
if (result != PING_RESULT_RESPONSE || server_info == NULL) {
return;
}
double rtt = tv->tv_sec * 1000.0 + tv->tv_usec / 1000.0;
tlog(TLOG_INFO, "from %15s: seq=%d ttl=%d time=%.3f\n", host, seqno, ttl, rtt);
server_info->ttl = ttl;
}
/* add dns server information */
int _dns_client_server_add(char *server_ip, struct addrinfo *gai, dns_server_type_t server_type, int result_flag)
int _dns_client_server_add(char *server_ip, struct addrinfo *gai, dns_server_type_t server_type, unsigned int result_flag, int ttl)
{
struct dns_server_info *server_info = NULL;
@@ -238,6 +252,11 @@ int _dns_client_server_add(char *server_ip, struct addrinfo *gai, dns_server_typ
if (server_info == NULL) {
goto errout;
}
if (server_type != DNS_SERVER_UDP) {
result_flag &= (~DNSSERVER_FLAG_CHECK_TTL);
}
memset(server_info, 0, sizeof(*server_info));
server_info->ai_family = gai->ai_family;
server_info->ai_addrlen = gai->ai_addrlen;
@@ -245,6 +264,7 @@ int _dns_client_server_add(char *server_ip, struct addrinfo *gai, dns_server_typ
server_info->fd = 0;
server_info->status = DNS_SERVER_STATUS_INIT;
server_info->result_flag = result_flag;
server_info->ttl = ttl;
if (gai->ai_addrlen > sizeof(server_info->in6)) {
tlog(TLOG_ERROR, "addr len invalid, %d, %zd, %d", gai->ai_addrlen, sizeof(server_info->addr), server_info->ai_family);
@@ -253,13 +273,13 @@ int _dns_client_server_add(char *server_ip, struct addrinfo *gai, dns_server_typ
memcpy(&server_info->addr, gai->ai_addr, gai->ai_addrlen);
/* start ping task */
#if 0
server_info->ping_host = fast_ping_start(server_ip, 0, 60000, 1000, NULL, server_info);
if (server_info->ping_host == NULL) {
tlog(TLOG_ERROR, "start ping failed.");
goto errout;
if (ttl == 0 && (result_flag & DNSSERVER_FLAG_CHECK_TTL)) {
server_info->ping_host = fast_ping_start(server_ip, 0, 60000, 1000, _dns_client_server_update_ttl, server_info);
if (server_info->ping_host == NULL) {
tlog(TLOG_ERROR, "start ping failed.");
goto errout;
}
}
#endif
/* add to list */
pthread_mutex_lock(&client.server_list_lock);
@@ -352,7 +372,7 @@ int _dns_client_server_remove(char *server_ip, struct addrinfo *gai, dns_server_
return -1;
}
int _dns_client_server_operate(char *server_ip, int port, dns_server_type_t server_type, int result_flag, int operate)
int _dns_client_server_operate(char *server_ip, int port, dns_server_type_t server_type, int result_flag, int ttl, int operate)
{
char port_s[8];
int sock_type;
@@ -386,7 +406,7 @@ int _dns_client_server_operate(char *server_ip, int port, dns_server_type_t serv
}
if (operate == 0) {
ret = _dns_client_server_add(server_ip, gai, server_type, result_flag);
ret = _dns_client_server_add(server_ip, gai, server_type, result_flag, ttl);
if (ret != 0) {
goto errout;
}
@@ -405,14 +425,14 @@ errout:
return -1;
}
int dns_add_server(char *server_ip, int port, dns_server_type_t server_type, int result_flag)
int dns_add_server(char *server_ip, int port, dns_server_type_t server_type, int result_flag, int ttl)
{
return _dns_client_server_operate(server_ip, port, server_type, result_flag, 0);
return _dns_client_server_operate(server_ip, port, server_type, result_flag, ttl, 0);
}
int dns_remove_server(char *server_ip, int port, dns_server_type_t server_type)
{
return _dns_client_server_operate(server_ip, port, server_type, 0, 1);
return _dns_client_server_operate(server_ip, port, server_type, 0, 0, 1);
}
int dns_server_num(void)
@@ -684,6 +704,8 @@ static int _dns_client_create_socket_udp(struct dns_server_info *server_info)
{
int fd = 0;
struct epoll_event event;
const int on = 1;
const int val=255;
fd = socket(server_info->ai_family, SOCK_DGRAM, 0);
if (fd < 0) {
@@ -701,6 +723,8 @@ static int _dns_client_create_socket_udp(struct dns_server_info *server_info)
server_info->fd = fd;
server_info->status = DNS_SERVER_STATUS_CONNECTIONLESS;
setsockopt(server_info->fd, IPPROTO_IP, IP_RECVTTL, &on, sizeof(on));
setsockopt(server_info->fd, SOL_IP, IP_TTL, &val, sizeof(val));
return 0;
errout:
@@ -857,15 +881,45 @@ static int _dns_client_process_udp(struct dns_server_info *server_info, struct e
struct sockaddr_storage from;
socklen_t from_len = sizeof(from);
char from_host[DNS_MAX_CNAME_LEN];
struct msghdr msg;
struct iovec iov;
char ans_data[4096];
int ttl = 0;
struct cmsghdr *cmsg;
/* receive from udp */
len = recvfrom(server_info->fd, inpacket, sizeof(inpacket), 0, (struct sockaddr *)&from, (socklen_t *)&from_len);
memset(&msg, 0, sizeof(msg));
iov.iov_base = (char *)inpacket;
iov.iov_len = sizeof(inpacket);
msg.msg_name = &from;
msg.msg_namelen = sizeof(from);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = ans_data;
msg.msg_controllen = sizeof(ans_data);
len = recvmsg(server_info->fd, &msg, MSG_DONTWAIT);
if (len < 0) {
tlog(TLOG_ERROR, "recvfrom failed, %s\n", strerror(errno));
return -1;
}
from_len = msg.msg_namelen;
tlog(TLOG_DEBUG, "recv udp, from %s", gethost_by_addr(from_host, (struct sockaddr *)&from, from_len));
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == SOL_IP
&& cmsg->cmsg_type == IP_TTL
) {
uint8_t * ttlPtr = (uint8_t *)CMSG_DATA(cmsg);
ttl = *ttlPtr;
break;
}
}
tlog(TLOG_DEBUG, "recv udp, from %s, ttl: %d", gethost_by_addr(from_host, (struct sockaddr *)&from, from_len), ttl);
if ((ttl != server_info->ttl) && (server_info->result_flag & DNSSERVER_FLAG_CHECK_TTL)) {
tlog(TLOG_DEBUG, "TTL mismatch, from:%d, local %d, discard result", ttl, server_info->ttl);
return 0;
}
time(&server_info->last_recv);
if (_dns_client_recv(server_info, inpacket, len, (struct sockaddr *)&from, from_len) != 0) {