#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <stdio.h>
#include <sys/socket.h>
#include <linux/in.h>
#include <string.h>
#include <sasl/sasl.h>

int sfp;
struct sockaddr_in s_add,c_add;
int sin_size;

typedef struct kClient {
	int fp;
	int auth_complete;
	int begin_auth;
	sasl_conn_t *conn;
} kClient;

int listen_port() {
	unsigned short portnum=2345;

	sfp = socket(AF_INET, SOCK_STREAM, 0);
	if(-1 == sfp) {
		printf("socket fail ! \n");
		return -1;
	}

	/* 填充服务器端口地址信息，以便下面使用此地址和端口监听 */
	bzero(&s_add,sizeof(struct sockaddr_in));
	s_add.sin_family=AF_INET;
	s_add.sin_addr.s_addr=htonl(INADDR_ANY); /* 这里地址使用全0，即所有 */
	s_add.sin_port=htons(portnum);
	/* 使用bind进行绑定端口 */
	if(-1 == bind(sfp,(struct sockaddr *)(&s_add), sizeof(struct sockaddr)))
	{
		printf("bind fail !\n");
		return -1;
	}
	/* 开始监听相应的端口 */
	if(-1 == listen(sfp,5))
	{
		printf("listen fail !\n");
		return -1;
	}
	printf("Hello,welcome to my server !\n");
	return 0;
}

kClient *createClient(int fp) {
	kClient *c = malloc(sizeof(kClient));
	c->fp = fp;
	c->auth_complete = -1;
	c->begin_auth = 0;
	c->conn = NULL;
	return c;
}

int auth_client(kClient *c) {
	if (!c->begin_auth && sasl_server_new("sample", "DOMAIN.COM",
				"DOMAIN.COM", "127.0.0.1", "127.0.0.1", NULL,
				0, &c->conn) == SASL_OK) {
		printf("Allocating sasl connection state");
		return 1;
	}
	const char *mech = "GSSAPI";
	int recbytes;
	char buffer[1024]={0};
	if ((recbytes = read(c->fp, buffer, 1024)) == -1) {
		printf("read failed\n");
		close(c->fp);
		return 1;
	}
	buffer[recbytes] = '\0';
	char *out;
	unsigned len = 0;
	int result = sasl_server_start(c->conn, mech, buffer, recbytes, &out, &len);
	if (result != SASL_OK && result != SASL_CONTINUE) {
		printf("auth failed ,%s\n", sasl_errdetail(c->conn));
		write(c->fp, "auth failed\n", 11);
		close(c->fp);
	}
	while (result == SASL_CONTINUE) {
		if (write(c->fp, out, len) == -1) {
			printf("write failed\n");
			return 1;
		}
		if (recbytes = read(c->fp, buffer, 1024)) {
			printf("write failed\n");
			return 1;
		}
		result = sasl_server_step(c->conn, buffer, recbytes, &out, &len);
		if (result != SASL_OK && result != SASL_CONTINUE) {
			printf("auth failed ,%s\n", sasl_errdetail(c->conn));
			write(c->fp, "auth failed\n", 11);
			close(c->fp);
			return 1;
		}
	}
	return 0;
}

void readQuery(kClient *c) {
	char buffer[1024]={0};
	int recbytes;
	/* 这里使用write向客户端发送信息，也可以尝试使用其他函数实现 */
	if(-1 == write(c->fp,"need_auth",9))
	{
		printf("write fail!\n");
		close(c->fp);
		return;
	}
	printf("write ok!\n");
	while (1) {
		if(-1 == (recbytes = read(c->fp,buffer,1024))) {
			printf("read data fail !\n");
			close(c->fp);
		}
		if (c->auth_complete != 1 && auth_client(c) != 0) {
			printf("auth failed!\n");
			break;
		}
		if(-1 == write(c->fp,"need_auth",9)) {
			printf("write fail!\n");
			break;
		}
	}
	close(c->fp);
}


int init_sasl() {
	int result = sasl_server_init(NULL, "sample");
	if (result != SASL_OK) {
		printf("Initializing libsasl");
		return 1;
	}
	return 0;
}

int main()
{
	if (listen_port() != 0 && init_sasl() != 0)
	{
		return 1;
	}
	while(1)
	{
		sin_size = sizeof(struct sockaddr_in);
		int nfp = accept(sfp, (struct sockaddr *)(&c_add), &sin_size);
		if(-1 == nfp)
		{
			printf("accept fail !\r\n");
			return -1;
		}

		printf("accept ok!\nServer start get connect from %#x : %#x\n", ntohl(c_add.sin_addr.s_addr), ntohs(c_add.sin_port));
		kClient *c = createClient(nfp);
		readQuery(c);
	}
	close(sfp);
	return 0;
}