5_11.cpp

// 修改TCP接收缓冲区的服务器程序
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<assert.h>
#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<errno.h>
#include<string.h>

#define BUFFER_SIZE 1024

int main(int argc, char* argv[]){
    if(argc <= 2){
        printf("usage: %s IP PORT BUFFER\n", basename(argv[0]));
        return 1;
    }

    const char* ip = argv[1];
    int port = atoi(argv[2]);

    struct sockaddr_in address;
    bzero(&address, sizeof(address));
    address.sin_family = AF_INET;
    inet_pton(AF_INET, ip, &address.sin_addr);
    address.sin_port = htons(port);

    int sock = socket(PF_INET, SOCK_STREAM, 0);
    assert(sock >= 0);
    int recvbuf = atoi(argv[3]);
    int len = sizeof(recvbuf);
    setsockopt(sock, SOL_SOCKET, SO_RCVBUF, &recvbuf, sizeof(recvbuf));
    getsockopt(sock, SOL_SOCKET, SO_RCVBUF, &recvbuf, (socklen_t*)&len);
    printf("the tcp receive buffer size after setting is %d\n", recvbuf);

    int ret = bind(sock, (struct sockaddr*)&address, sizeof(address));
    assert(ret != -1);

    ret = listen(sock, 5);
    assert(ret != -1);

    struct sockaddr_in client;
    socklen_t client_addrlength = sizeof(client);
    int connfd = accept(sock, (struct sockaddr*)&client, &client_addrlength);
    if(connfd < 0){
        printf("errno is : %d\n", errno);
    }
    else{
        char buffer[BUFFER_SIZE];
        memset(buffer, '\0', BUFFER_SIZE);
        while(recv(connfd, buffer, BUFFER_SIZE-1, 0) > 0){}
        close(connfd);
    }
    close(sock);
    return 0;
}