select实现tcp并发服务器

#include "test.h"

#define SER_IP "192.168.42.106"
#define SER_PORT 8888
 
int create_socket()
{
    int sfd = socket(AF_INET, SOCK_STREAM, 0);
    if(sfd == -1)
    {
        perror("socket error");
        exit(-1);
    }
    printf("sfd = %d\n", sfd);

    return sfd;
}

int start_reuse(int sfd)
{
    int reuse = -1; 
    if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) == -1)
    {
        perror("setsockopt error");
        exit(-1);
    }
    printf("端口号快速重用成功\n");

    return reuse;
}

void start_listen(int sfd)
{
    if (listen(sfd, 128) == -1)
    {
        perror("listen error");
        exit(-1);
    }
    printf("listen success\n");
}

int main(int argc, const char *argv[])
{
    int sfd = create_socket();

    int reuse = start_reuse(sfd);
 
    struct sockaddr_in sin;
    sin.sin_family = AF_INET;
    sin.sin_port = htons(SER_PORT);
    sin.sin_addr.s_addr = inet_addr(SER_IP);
    if (bind(sfd, (struct sockaddr*)&sin, sizeof(sin)) == -1)
    {
        perror("bind error");
        return -1;
    }

    start_listen(sfd);

    struct sockaddr_in cin;
    socklen_t socklen = sizeof(cin);
    int newfd = -1;
    char sbuf[128] = "";

    fd_set readfds, tempfds;
    FD_ZERO(&readfds);
    FD_SET(0, &readfds);
    FD_SET(sfd, &readfds);

    int maxfd = sfd;
    struct sockaddr_in cin_arr[1024];

    while(1)
    {
        tempfds = readfds;

        int res = select(maxfd + 1, &tempfds, NULL, NULL, NULL);
        if (res == -1)
        {
            perror("select error");
            exit(-1);
        }
        else if (res == 0)
        {
            printf("time out\n");
            exit(-1);
        }

        for (int i = 0; i < maxfd; i++)
        {
            if (!FD_ISSET(i, &tempfds))
            {
                continue;
            }

            if (i == sfd)
            {
                newfd = accept(sfd, (struct sockaddr*)&cin, &socklen);
                if (newfd == -1)
                {
                    perror("accept error");
                    exit(-1);
                }

                printf("newfd=%d 您已有新客户上线\n", newfd);
                printf("客户端IP: %s, 端口号: %d\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port));

                FD_SET(newfd, &readfds);
                cin_arr[newfd] = cin;
                if (newfd > maxfd)
                {
                    maxfd = newfd;
                }
            }
            else if (i == 0)
            {
                fgets(sbuf, sizeof(sbuf), stdin);
                sbuf[strlen(sbuf) - 1] = 0;
                printf("触发了键盘输入事件: %s\n", sbuf);

                for (int k = 4; k < maxfd; k++)
                {
                    send(k, sbuf, strlen(sbuf), 0);
                }
            }
            else
            {
                char rbuf[128] = "";
                bzero(rbuf, sizeof(rbuf));

                int res = recv(i, rbuf, sizeof(rbuf), 0);
                if (res == 0)
                {
                    printf("客户端已下线\n");
                    close(i);

                    FD_CLR(i, &readfds);
                    for (int j = maxfd; j >= 0; j--)
                    {
                        if (FD_ISSET(j, &readfds))
                        {
                            maxfd = j;
                            break;
                        }
                    }

                    continue;
                }

                printf("[%s:%d]: %s\n", inet_ntoa(cin_arr[i].sin_addr), ntohs(cin_arr[i].sin_port), rbuf);

                strcat(rbuf, "*_*");
                send(i, rbuf, strlen(rbuf), 0);
            }
        }
    }
    
    close(sfd);
 
    return 0;
}

poll实现tcp客户端

#include "test.h"

#define SER_IP "192.168.191.128"
#define SER_PORT 8888

#define CLI_IP "192.168.191.128"
#define CLI_PORT 9999
 
int create_socket()
{
    int sfd = socket(AF_INET, SOCK_STREAM, 0);
    if(sfd == -1)
    {
        perror("socket error");
        exit(-1);
    }
    printf("sfd = %d\n", sfd);

    return sfd;
}

int start_reuse(int sfd)
{
    int reuse = -1; 
    if (setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) == -1)
    {
        perror("setsockopt error");
        exit(-1);
    }
    printf("端口号快速重用成功\n");

    return reuse;
}

void start_listen(int sfd)
{
    if (listen(sfd, 128) == -1)
    {
        perror("listen error");
        exit(-1);
    }
    printf("listen success\n");
}

int main(int argc, const char *argv[])
{
    int sfd = create_socket();

    int reuse = start_reuse(sfd);
 
    struct sockaddr_in cin;
    cin.sin_family = AF_INET;
    cin.sin_port = htons(CLI_PORT);
    cin.sin_addr.s_addr = inet_addr(CLI_IP);
    if (bind(sfd, (struct sockaddr*)&cin, sizeof(cin)) == -1)
    {
        perror("bind error");
        return -1;
    }

    struct sockaddr_in sin;
    sin.sin_family = AF_INET;
    sin.sin_port = htons(SER_PORT);
    sin.sin_addr.s_addr = inet_addr(SER_IP);

    if (connect(sfd, (struct sockaddr*)&sin, sizeof(sin)) == -1)
    {
        perror("connect error");
        exit(-1);
    }
    printf("connect success\n");

    struct pollfd pfd[2];
    pfd[0].fd = 0;
    pfd[0].events = POLLIN;
    pfd[1].fd = sfd;
    pfd[1].events = POLLIN;

    char wbuf[128] = "";
    while(1)
    {
        int res = poll(pfd, 2, -1);
        if (res == -1)
        {
            perror("poll error");
            exit(-1);
        }
        else if (res == 0)
        {
            printf("time out\n");
            exit(-1);
        }

        if (pfd[0].revents == POLLIN)
        {
            bzero(wbuf, sizeof(wbuf));

            printf("请输入>>>");
            fgets(wbuf, sizeof(wbuf), stdin);
            wbuf[strlen(wbuf) - 1] = 0;
    
            send(sfd, wbuf, strlen(wbuf), 0);
            printf("发送成功\n");

            if (strcmp(wbuf, "quit") == 0)
            {
                break;
            }
        }
        
        if (pfd[1].revents == POLLIN)
        {
            bzero(wbuf, sizeof(wbuf));
            recv(sfd, wbuf, sizeof(wbuf), 0);

            printf("收到消息: %s\n", wbuf);
        }
    }
    
    close(sfd);
 
    return 0;
}