Linux 網絡編程四（socket多線程升級版）

時間 2019-11-15

原文原文鏈接

//網絡編程--客戶端
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <pthread.h>
#include <netinet/in.h>
#include <arpa/inet.h>

/*
 強調：當客戶端鏈接服務器時，服務器會產生一個新的文件描述符（套接字）與客戶端交互，這個新的套接字不是服務器端的監聽套接字
 套接字是全雙工的，在一個網絡管道中的兩端，每端均可以進行讀寫操做。
 */

typedef struct _recvmodel
{
    int st;
    struct sockaddr_in * addr;
} RecvModel;

//send message
void * send_thread(void *arg)
{
    if (arg == NULL)
    {
        printf("param is not allow NULL!\n");
        return NULL;
    }
    int st = *(int *) arg;
    char buf[1024] = { 0 };
    while (1)
    {
        read(STDIN_FILENO, buf, sizeof(buf));
        if (send(st, buf, strlen(buf), 0) == -1)
        {
            printf("send failed ! error message %s\n", strerror(errno));
            return NULL;
        }
        memset(buf, 0, sizeof(buf));
    }
    return NULL;
}

//recv message
void * recv_thread(void * arg)
{
    if (arg == NULL)
    {
        printf("param is not allow NULL!\n");
        return NULL;
    }
    RecvModel * model = (RecvModel *) arg;
    int flag = 0;
    char buf[1024] = { 0 };
    while (1)
    {
        flag = recv(model->st, buf, sizeof(buf), 0);
        if (flag == 0)
        {
            printf("對方已經關閉鏈接！\n");
            return NULL;
        } else if (flag == -1)
        {
            printf("recv failed ! error message : %s\n", strerror(errno));
            return NULL;
        }
        printf("from %s:%s", inet_ntoa(model->addr->sin_addr), buf);
        memset(buf, 0, sizeof(buf));
    }
    return NULL;
}

int main(int arg, char *args[])
{
    //打開socket
    int st = socket(AF_INET, SOCK_STREAM, 0);
    if (st == -1)
    {
        printf("open socket failed! error message:%s\n", strerror(errno));
        return -1;
    }
    //定義IP地址結構
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    //設置TCP/IP鏈接
    addr.sin_family=AF_INET;
    //設置端口號
    addr.sin_port = htons(8080);
    //設置容許鏈接地址
    addr.sin_addr.s_addr = inet_addr("192.168.1.102");
    //connect server
    int numx = connect(st, (struct sockaddr *) &addr, sizeof(addr));
    if (numx == -1)
    {
        printf("connect server failed ! error message :%s\n", strerror(errno));
        goto END;
    }

    RecvModel model;
    model.st = st;
    model.addr = &addr;
    //開啓多線程--線程1接收消息，線程2發送消息
    pthread_t thr1, thr2;
    if (pthread_create(&thr1, NULL, send_thread, &st) != 0)
    {
        printf("create thread failed ! \n");
        goto END;
    }
    if (pthread_create(&thr2, NULL, recv_thread, &model) != 0)
    {
        printf("create thread failed ! \n");
        goto END;
    }
    pthread_join(thr1, NULL);
    pthread_join(thr2, NULL);
    END: close(st);
    return 0;
}

//網絡編程--服務端
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <pthread.h>
#include <netinet/in.h>
#include <arpa/inet.h>

typedef struct _recvmodel
{
    int st;
    struct sockaddr_in * addr;
} RecvModel;

//send message
void * send_thread(void *arg)
{
    if (arg == NULL)
    {
        printf("param is not allow NULL!\n");
        return NULL;
    }
    int st = *(int *) arg;
    char buf[1024] = { 0 };
    while (1)
    {
        read(STDIN_FILENO, buf, sizeof(buf));
        if (send(st, buf, strlen(buf), 0) == -1)
        {
            printf("send failed ! error message %s\n", strerror(errno));
            return NULL;
        }
        memset(buf, 0, sizeof(buf));
    }
    return NULL;
}

//recv message
void * recv_thread(void * arg)
{
    if (arg == NULL)
    {
        printf("param is not allow NULL!\n");
        return NULL;
    }
    RecvModel * model = (RecvModel *) arg;
    int flag = 0;
    char buf[1024] = { 0 };
    while (1)
    {
        flag = recv(model->st, buf, sizeof(buf), 0);
        if (flag == 0)
        {
            printf("對方已經關閉鏈接！\n");
            return NULL;
        } else if (flag == -1)
        {
            printf("recv failed ! error message : %s\n", strerror(errno));
            return NULL;
        }
        printf("from %s:%s", inet_ntoa(model->addr->sin_addr), buf);
        memset(buf, 0, sizeof(buf));
    }
    return NULL;
}

int main(int arg, char *args[])
{

    //short port = atoi(args[1]);
    //打開socket
    int st = socket(AF_INET, SOCK_STREAM, 0);
    if (st == -1)
    {
        printf("open socket failed! error message:%s\n", strerror(errno));
        return -1;
    }
    //設置系統地址可重用
    int on = 1;
    if (setsockopt(st, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
    {
        printf("setsockpot failed ! error message %s\n", strerror(errno));
        goto END;
    }
    //定義IP地址結構
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    //設置TCP/IP鏈接
    addr.sin_family = AF_INET;
    //設置端口號
    addr.sin_port = htons(8080);
    //設置容許鏈接地址
    addr.sin_addr.s_addr = htonl(INADDR_ANY);
    //bind ip
    if (bind(st, (struct sockaddr *) &addr, sizeof(addr)) == -1)
    {
        printf("bind ip failed ! error message :%s\n", strerror(errno));
        goto END;
    }
    //監聽鏈接
    if (listen(st, 20) == -1)
    {
        printf("listen failed ! error message :%s\n", strerror(errno));
        goto END;
    }
    //接收客戶端鏈接（阻塞）
    struct sockaddr_in client_addr;
    memset(&client_addr, 0, sizeof(client_addr));
    socklen_t client_addrlen = sizeof(client_addr);
 //強調：這裏的client_addrlen並非爲了在函數中設置client_addrlen的值，而是經過client_addrlen的值來判斷client_addr是一個什麼類型的結構，
 //因此這裏client_addrlen設置爲0是錯誤的，必須是struct sockaddr_in這個結構的大小，否則返回值不正確 int client_st = accept(st, (struct sockaddr *) &client_addr,
            &client_addrlen);
    if (client_st == -1)
    {
        printf("accept failed ! error message :%s\n", strerror(errno));
        goto END;
    }
    RecvModel model;
    model.st = client_st;
    model.addr = &client_addr;
    printf("accept by=%s\n",inet_ntoa(client_addr.sin_addr));
    //開啓多線程--線程1接收消息，線程2發送消息
    pthread_t thr1, thr2;
    if (pthread_create(&thr1, NULL, send_thread, &client_st) != 0)
    {
        printf("create thread failed ! \n");
        goto END;
    }
    if (pthread_create(&thr2, NULL, recv_thread, &model) != 0)
    {
        printf("create thread failed ! \n");
        goto END;
    }
    pthread_join(thr1, NULL);
    pthread_join(thr2, NULL);
    //關閉客戶端管道
    close(client_st);
    END: close(st);
    return 0;
}

.SUFFIXES:.c .o
CC=gcc
SRCS1=mserver.c
SRCS2=mclient.c
OBJS1=$(SRCS1:.c=.o)
OBJS2=$(SRCS2:.c=.o)
EXEC1=mserv
EXEC2=mcli

start:$(OBJS1) $(OBJS2)
    $(CC) -o $(EXEC1) $(OBJS1) -lpthread
    $(CC) -o $(EXEC2) $(OBJS2) -lpthread
    @echo "^_^ ------ OK ------ ^_^"
.c.o:
    $(CC) -Wall -g -o $@ -c $<
clean:
    rm -f $(OBJS1)
    rm -f $(OBJS2)
    rm -f $(EXEC1)
    rm -f $(EXEC2)

小結：這段升級版程序花費3小時，出現一個錯誤提示：" Transport endpoint is not connected"，我仔細查找資料，
網上說是socket套接字不對，可我程序中套接字是正確的，
我沒有辦法，可是我有一個成功的程序，就是初版socket程序，我將原來的socket程序複製到個人新程序中，一句句替換，終於發現這個問題
問題：我缺乏addr.sin_family = AF_INET;//將網絡地址類型設置爲TCP/IP協議；這句代碼。缺乏這段代碼是致使報錯的主要緣由。
另外注意我代碼中強調的內容--網絡管道是全雙工的