Linux 网络编程学习-简单实现TCP通讯

以后，争取每天写一个工作除外的程序，练习练习代码能力。主要是方便自己看，不是学习系列,误伤莫怪。
上代码了

root@bt:~/c/network# cat server.c
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
int main(int argc, char *argv[])
{
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;
    int port;
    int sin_size;
    int sockfd, new_sockfd;
    char hello[]="hello,world for inetd";
    if(argc != 2) {
        fprintf(stderr, "[Usage:] %s postan", argv[0]);
        exit(1);
    }
    port = atoi(argv[1]);
    printf("port=%dn", port);
    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        fprintf(stderr, "socket error %san", strerror(errno));
        exit(1);
    }
    int n = 1;
    setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &n ,sizeof(n));
    bzero(&server_addr, sizeof(struct sockaddr_in));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    server_addr.sin_port = htons(port);
    if(bind(sockfd, (struct sockaddr *)(&server_addr), sizeof(struct sockaddr)) == -1){
        fprintf(stderr,"bind error %san", strerror(errno));
        exit(1);
    }
    if(listen(sockfd, 5) == -1) {
        fprintf(stderr, "listen error %san", strerror(errno));
        exit(1);
    }
    while ( 1 ) {
        sin_size = sizeof(struct sockaddr);
        if((new_sockfd=accept(sockfd, (struct sockaddr *)(&client_addr), &sin_size)) == -1) {
            fprintf(stderr, "accept error %san", strerror(errno));
            exit(1);
        }
        fprintf(stderr, "server get connection from %sn", inet_ntoa(client_addr.sin_addr));
        if(write(new_sockfd, hello, strlen(hello)) == -1) {
            fprintf(stderr, "write to client error %san", strerror(errno));
            close(new_sockfd);
            continue;
        }
        close(new_sockfd);
    }
    close(sockfd);
    return 0;
}

root@bt:~/c/network# cat client.c
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
int main(int argc, char **argv)
{
    struct sockaddr_in server_addr;
    int	sockfd, port, nbytes;
    char	buffer[1024];
    struct hostent *host;
    if(argc != 3) {
        fprintf(stderr, "Usage:%s hostname port", argv[0]);
        exit(1);
    }
    if((host=gethostbyname(argv[1])) == NULL) {
        fprintf(stderr, "gethostbyname error %sna", strerror(errno));
        exit(1);
    }
    if((port=atoi(argv[2])) < 0) {
        fprintf(stderr, "port input errorna");
        exit(1);
    }
    if((sockfd=socket(AF_INET, SOCK_STREAM, 0)) == -1 ){
        fprintf(stderr, "socket error %sna", strerror(errno));
        exit(1);
    }
    bzero(&server_addr, sizeof(struct sockaddr_in));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr=inet_addr(argv[1]);
    server_addr.sin_port = htons(port);
    if(connect(sockfd, (struct sockaddr *)(&server_addr), sizeof(struct sockaddr )) == -1) {
        fprintf(stderr, "connect error %sna", strerror(errno));
        exit(1);
    }
    if((nbytes=read(sockfd, buffer, 1024)) == -1) {
        fprintf(stderr, "read sockfd error %sna", strerror(errno));
        exit(1);
    }
    buffer[nbytes]='0';
    printf("buffer=[%s]n", buffer);
    close(sockfd);
    return 0;
}

root@bt:~/c/network# cat Makefile
all:server client
server:server.c
    gcc $^ -o $@
client:client.c
    gcc $^ -o $@