#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;

char *server = "server";

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) {
        int result = sasl_server_new(server, "hadoop.test.hadoop.com", "TEST.HADOOP.COM", NULL, NULL, NULL, 0, &c->conn);
        if (result != SASL_OK) {
            printf("Allocating sasl connection state, %s\n", sasl_errdetail(c->conn));
            return 1;
        }
    }

    const char *mech = "GSSAPI";
    char buffer[1024] = {0};
    int client_len = readTicket(c, buffer);
    char *out;
    unsigned len = 0;
    buffer[client_len] = '\n';
    printf("ticket=%s, len=%d\n", buffer, client_len);
    int result = sasl_server_start(c->conn, mech, buffer, client_len, &out, &len);
    if (result != SASL_OK && result != SASL_CONTINUE) {
        printf("auth failed ,%s, result=%d\n", sasl_errdetail(c->conn), result);
        write(c->fp, "auth failed\n", 11);
        close(c->fp);
        return;
    }
    printf("sasl_server_start ok\n");
    while (result == SASL_CONTINUE) {
        writeTicket(c, out, len);
        client_len = readTicket(c, buffer);
        result = sasl_server_step(c->conn, buffer, client_len, &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;
        }
        printf("sasl_server_start ok");
    }
    return 0;
}

int readTicket(kClient *c, char *ticket) {
    char len_str[10] = {0};
    int recbytes;
    if (-1 == (recbytes = read(c->fp, len_str, 25))) {
        printf("read len fail !\n");
        close(c->fp);
        return 0;
    }
    int len = atoi(len_str);
    printf("read len=%s\n", len_str);
    if (-1 == (recbytes = read(c->fp, ticket, len))) {
        printf("read data fail !\n");
        close(c->fp);
        return 0;
    }
    return len;
}

void writeTicket(kClient *c, char *data, unsigned len) {
    char len_str[10] = {0};
    sprintf(len_str, "%d", len);
    if (-1 == write(c->fp, len_str, 10)) {
        printf("write failed\n");
        return 1;
    }
    if (-1 == write(c->fp, data, len)) {
        printf("write failed\n");
        return 1;
    }
}

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;
    }

    if (auth_client(c) != 0) {
        printf("auth failed!\n");
        return;
    }

    close(c->fp);
}

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

int main() {
    if (listen_port() != 0) {
        return 1;
    }
    init_sasl();
    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;
}