tcp/udp 例程

TCP
server.c

/* Copyright(C) 2012 for free
 * All right reserved
 */
/**
 * @file server.c
 * @synopsis  tcp 测试例程
 * @version 1.0
 * @date 2012-07-06
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <ctype.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define MAXLINE 80
#define SERV_PORT 8000

int main(int argc,char *argv[])
{
    struct sockaddr_in servaddr, cliaddr;
    socklen_t cliaddr_len;
    int sockfd, connfd;
    char buf[MAXLINE];
    char str[INET_ADDRSTRLEN];
    int i, n;

    sockfd = socket(AF_INET, SOCK_STREAM, 0);

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(SERV_PORT);

    i = 1;
    setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&i,sizeof(i));
    bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

    listen(sockfd, 20);

    printf("Accepting connections ...\n");
    while (1) {
        memset(buf,0,sizeof(buf));
        cliaddr_len = sizeof(cliaddr);
        connfd = accept(sockfd,
                (struct sockaddr *)&cliaddr, &cliaddr_len);

        n = read(connfd, buf, MAXLINE);
        printf("received from %s at PORT %d : %s\n",
               inet_ntop(AF_INET, &cliaddr.sin_addr, str, sizeof(str)),
               ntohs(cliaddr.sin_port),buf);

        for (i = 0; i < n; i++)
            buf[i] = toupper(buf[i]);
        write(connfd, buf, n);
        close(connfd);
    }

    close(sockfd);
    return 0;
}

client.c

/* Copyright(C) 2012 for free
* All right reserved
*/
/**
* @file client.c
* @synopsis  tcp 测试例程
* @version 1.0
* @date 2012-07-06
*/
#include
#include
#include
#include
#include
#include
#include

#define MAXLINE 80
#define SERV_PORT 8000

int main(int argc, char *argv[])
{
struct sockaddr_in servaddr;
char buf[MAXLINE];
int sockfd, n;
char *str;

if (argc != 2) {
fputs("usage: ./client message\n",stderr);
exit(1);
}
str = argv[1];

sockfd = socket(AF_INET, SOCK_STREAM, 0);

bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr);
servaddr.sin_port = htons(SERV_PORT);

connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

write(sockfd, str, strlen(str));

n = read(sockfd, buf, MAXLINE);
printf("Response from server:\n");
write(STDOUT_FILENO, buf, n);
printf("\n");

close(sockfd);
return 0;
}

UDP
server.c

/* Copyright(C) 2012 for free
 * All right reserved
 */
/**
 * @file server.c
 * @synopsis  udp 测试例程
 * @version 1.0
 * @date 2012-07-06
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define MAXLINE 80
#define SERV_PORT 8000

int main(int argc,char *argv[])
{
    struct sockaddr_in servaddr, cliaddr;
    socklen_t cliaddr_len;
    int sockfd;
    char buf[MAXLINE];
    char str[INET_ADDRSTRLEN];
    int i, n;

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(SERV_PORT);

    bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

    printf("Accepting connections ...\n");
    while (1) {
        memset(buf,0,sizeof(buf));
        cliaddr_len = sizeof(cliaddr);
        n = recvfrom(sockfd, buf, MAXLINE, 0, (struct sockaddr *)&cliaddr, &cliaddr_len);
        if (n == -1)
            perror("recvfrom error");
        printf("received from %s at PORT %d is:%s\n",
               inet_ntop(AF_INET, &cliaddr.sin_addr, str, sizeof(str)),
               ntohs(cliaddr.sin_port),buf);
        for (i = 0; i < n; i++)
            buf[i] = toupper(buf[i]);
        n = sendto(sockfd, buf, n, 0, (struct sockaddr *)&cliaddr, sizeof(cliaddr));
        if (n == -1)
            perror("sendto error");
    }

    close(sockfd);
    return 0;
}

client.c

/* Copyright(C) 2012 for free
 * All right reserved
 */
/**
 * @file client.c
 * @synopsis  upd 测试例程
 * @version 1.0
 * @date 2012-07-06
 */
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define MAXLINE 80
#define SERV_PORT 8000

int main(int argc, char *argv[])
{
    struct sockaddr_in servaddr;
    int sockfd, n;
    char buf[MAXLINE];

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr);
    servaddr.sin_port = htons(SERV_PORT);

    printf("please input character:\n");
    while (fgets(buf, MAXLINE, stdin) != NULL) {
        n = sendto(sockfd, buf, strlen(buf), 0, (struct sockaddr *)&servaddr, sizeof(servaddr));
        if (n == -1)
            perror("sendto error");

        n = recvfrom(sockfd, buf, MAXLINE, 0, NULL, 0);
        if (n == -1)
            perror("recvfrom error");

        write(STDOUT_FILENO, buf, n);
        printf("please input character:\n");
    }

    close(sockfd);
    return 0;
}