update code

dns_client.c

@@ -0,0 +1,196 @@
+#include "dns_client.h"
+#include "atomic.h"
+#include "fast_ping.h"
+#include "hashtable.h"
+#include <arpa/inet.h>
+#include <errno.h>
+#include <linux/filter.h>
+#include <netdb.h>
+#include <netinet/icmp6.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/ip_icmp.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#define DNS_MAX_HOSTNAME 256
+
+#define DNS_INPACKET_SIZE 512
+
+#define DNS_MAX_EVENTS 64
+
+#define DNS_HOSTNAME_LEN 128  
+
+struct dns_query_server {
+    int fd;
+    int type;
+    char host[DNS_HOSTNAME_LEN];
+    list_head list;
+};
+
+struct dns_client {
+    pthread_t tid;
+    int run;
+    int epoll_fd;
+
+    list_head dns_server_list;
+
+    pthread_mutex_t map_lock;
+    DECLARE_HASHTABLE(hostmap, 6);
+
+    int udp;
+    int tcp;
+};
+struct dns_query_struct {
+    char host[DNS_MAX_HOSTNAME];
+    struct hlist_node host_node;
+};
+
+static struct dns_client client;
+
+static void tv_sub(struct timeval *out, struct timeval *in)
+{
+    if ((out->tv_usec -= in->tv_usec) < 0) { /* out -= in */
+        --out->tv_sec;
+        out->tv_usec += 1000000;
+    }
+    out->tv_sec -= in->tv_sec;
+}
+
+void _dns_client_period_run()
+{
+}
+
+static int _dns_client_process(struct dns_query_struct *dns_query, struct timeval *now)
+{
+    int len;
+    u_char inpacket[DNS_INPACKET_SIZE];
+    struct sockaddr_storage from;
+    socklen_t from_len = sizeof(from);
+
+    len = recvfrom(client.udp, inpacket, sizeof(inpacket), 0, (struct sockaddr *)&from, (socklen_t *)&from_len);
+    if (len < 0) {
+        fprintf(stderr, "recvfrom failed, %s\n", strerror(errno));
+        goto errout;
+    }
+
+    return 0;
+errout:
+    return -1;
+}
+
+static void *_dns_client_work(void *arg)
+{
+    struct epoll_event events[DNS_MAX_EVENTS + 1];
+    int num;
+    int i;
+    struct timeval last = { 0 };
+    struct timeval now = { 0 };
+    struct timeval diff = { 0 };
+    uint millisec = 0;
+
+    while (client.run) {
+        diff = now;
+        tv_sub(&diff, &last);
+        millisec = diff.tv_sec * 1000 + diff.tv_usec / 1000;
+        if (millisec >= 100) {
+            _dns_client_period_run();
+            last = now;
+        }
+
+        num = epoll_wait(client.epoll_fd, events, DNS_MAX_EVENTS, 100);
+        if (num < 0) {
+            gettimeofday(&now, 0);
+            usleep(100000);
+            continue;
+        }
+
+        if (num == 0) {
+            gettimeofday(&now, 0);
+            continue;
+        }
+
+        gettimeofday(&now, 0);
+        for (i = 0; i < num; i++) {
+            struct epoll_event *event = &events[i];
+            struct dns_query_struct *dns_query = (struct dns_query_struct *)event->data.ptr;
+            _dns_client_process(dns_query, &now);
+        }
+    }
+
+    close(client.epoll_fd);
+    client.epoll_fd = -1;
+
+    return NULL;
+}
+
+int dns_client_init()
+{
+    pthread_attr_t attr;
+    int epollfd = -1;
+    int ret;
+
+    if (client.epoll_fd > 0) {
+        return -1;
+    }
+
+    memset(&client, 0, sizeof(client));
+    pthread_attr_init(&attr);
+
+    epollfd = epoll_create1(EPOLL_CLOEXEC);
+    if (epollfd < 0) {
+        fprintf(stderr, "create epoll failed, %s\n", strerror(errno));
+        goto errout;
+    }
+
+    client.run = 1;
+    ret = pthread_create(&client.tid, &attr, _dns_client_work, NULL);
+    if (ret != 0) {
+        fprintf(stderr, "create client work thread failed, %s\n", strerror(errno));
+        goto errout;
+    }
+
+    pthread_mutex_init(&client.map_lock, 0);
+    hash_init(client.hostmap);
+    client.epoll_fd = epollfd;
+
+    return 0;
+errout:
+    if (client.tid > 0) {
+        void *retval = NULL;
+        client.run = 0;
+        pthread_join(client.tid, &retval);
+    }
+
+    if (epollfd) {
+        close(epollfd);
+    }
+
+    pthread_mutex_destroy(&client.map_lock);
+
+    return -1;
+}
+
+int dns_client_query(char *host)
+{
+    return 0;
+errout:
+    return -1;
+}
+
+void dns_client_exit()
+{
+    if (client.tid > 0) {
+        void *ret = NULL;
+        client.run = 0;
+        pthread_join(client.tid, &ret);
+    }
+
+    pthread_mutex_destroy(&client.map_lock);
+}