Add config

conf.c

@@ -0,0 +1,191 @@
+#include "conf.h"
+#include "tlog.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define MAX_LINE_LEN 1024
+#define MAX_KEY_LEN 64
+
+#define DEFAULT_DNS_PORT 53
+#define DEFAULT_DNS_CACHE_SIZE 512
+
+int dns_conf_port = DEFAULT_DNS_PORT;
+int dns_conf_cachesize = DEFAULT_DNS_CACHE_SIZE;
+struct dns_servers dns_conf_servers[DNS_MAX_SERVERS];
+int dns_conf_server_num;
+
+int config_port(char *value)
+{
+	int port = atoi(value);
+	if (port <= 0 || port >= 65535) {
+		return -1;
+	}
+
+	dns_conf_port = port;
+
+	return 0;
+}
+
+int config_parse_ip(char *value, char *ip, unsigned short *port)
+{
+	int offset = 0;
+	char *colon = NULL;
+
+	if (strstr(value, "[")) {
+		/* ipv6 with port */
+		char *bracket_end = strstr(value, "]");
+		if (bracket_end == NULL) {
+			return -1;
+		}
+
+		offset = bracket_end - value - 1;
+		memcpy(ip, value + 1, offset);
+		ip[offset] = 0;
+
+		colon = bracket_end + 1;
+
+	} else if (strstr(value, "::")) {
+		/* ipv6 without port */
+		strncpy(ip, value, DNS_MAX_IPLEN);
+		colon = NULL;
+	} else {
+		/* ipv4 */
+		colon = strstr(value, ":");
+		if (colon == NULL) {
+			/* without port */
+			strncpy(ip, value, DNS_MAX_IPLEN);
+		} else {
+			/* with port */
+			offset = colon - value;
+			colon++;
+			memcpy(ip, value, offset);
+		}
+	}
+
+	if (colon) {
+		/* get port num */
+		*port = atoi(colon);
+	} else {
+		*port = DEFAULT_DNS_PORT;
+	}
+
+	return 0;
+}
+
+int config_server(char *value, dns_conf_server_type_t type)
+{
+	int index = dns_conf_server_num;
+	struct dns_servers *server;
+	if (index >= DNS_MAX_SERVERS) {
+		tlog(TLOG_ERROR, "exceeds max server number");
+		return -1;
+	}
+
+	server = &dns_conf_servers[index];
+    if (config_parse_ip(value, server->server, &server->port) != 0) {
+		return -1;
+    }
+
+	server->type = type;
+	dns_conf_server_num++;
+
+	return 0;
+}
+
+int config_server_udp(char *value)
+{
+	return config_server(value, DNS_CONF_TYPE_UDP);
+}
+
+int config_server_tcp(char *value)
+{
+	return config_server(value, DNS_CONF_TYPE_TCP);
+}
+
+int config_server_http(char *value)
+{
+	return config_server(value, DNS_CONF_TYPE_HTTP);
+}
+
+int config_cache_size(char *value)
+{
+	int cache_size = atoi(value);
+	if (cache_size < 0) {
+		return -1;
+	}
+
+	dns_conf_cachesize = cache_size;
+
+	return 0;
+}
+
+struct config_item {
+	const char *item;
+	int (*item_func)(char *value);
+};
+
+struct config_item config_item[] = {
+	{"port", config_port},
+	{"server", config_server_udp},
+    {"server-tcp", config_server_tcp},
+    {"server-http", config_server_http},
+	{"cache-size", config_cache_size},
+};
+int config_item_num = sizeof(config_item) / sizeof(struct config_item);
+
+int load_conf(const char *file)
+{
+	FILE *fp = NULL;
+	char line[MAX_LINE_LEN];
+	char key[MAX_KEY_LEN];
+	char value[MAX_LINE_LEN];
+	int filed_num = 0;
+	int line_num = 0;
+	int i;
+
+	fp = fopen(file, "r");
+	if (fp == NULL) {
+		tlog(TLOG_ERROR, "config file %s not exist.", file);
+		return -1;
+	}
+
+	while (fgets(line, MAX_LINE_LEN, fp)) {
+		line_num++;
+		filed_num = sscanf(line, "%63s %1023[^\r\n]s", key, value);
+		if (filed_num <= 0) {
+			continue;
+		}
+
+		if (key[0] == '#') {
+			continue;
+		}
+
+		if (filed_num != 2) {
+			goto errout;
+		}
+
+		for (i = 0; i < config_item_num; i++) {
+			if (strncmp(config_item[i].item, key, MAX_KEY_LEN) != 0) {
+				continue;
+			}
+
+			if (config_item[i].item_func(value) != 0) {
+				goto errout;
+			}
+
+			break;
+		}
+	}
+
+	fclose(fp);
+
+	return 0;
+errout:
+	printf("invalid config at line %d: %s", line_num, line);
+	if (fp) {
+		fclose(fp);
+	}
+	return -1;
+}