c语言的tcp和udp客户端和服务器

都是最简单的用来记忆。

this is my 的git地址：https://github.com/yanjinyun/cLanguageTcpUdp

tcp最简单的服务器：

复制代码
int main(int argc, const char *argv[])
{
    int listenfd, acceptfd;
    struct sockaddr_in sin, cin;
    socklen_t clen;
    char buf[1024];

    signal(SIGCHLD, SIG_IGN);

    listenfd = socket(PF_INET, SOCK_STREAM, 0);

    sin.sin_family = PF_INET;
    sin.sin_port = htons(atoi(argv[2]));
    sin.sin_addr.s_addr = inet_addr(argv[1]);
    bind(listenfd, (struct sockaddr *)&sin, sizeof(sin));

    listen(listenfd, 5);

    while(1)
    {
        clen = sizeof(cin);
        printf("listen ......\n");
        acceptfd = accept(listenfd, (struct sockaddr *)&cin, &clen);
        printf("client %s %d connect\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port));

        if(fork() == 0)
        {
            close(listenfd);

            while(1)
            {
                bzero(buf, sizeof(buf));
                if(recv(acceptfd, buf, sizeof(buf), 0) == 0)
                {
                    printf("client %s %d exit\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port));
                    exit(0);
                }
                printf("recv(%s %d): %s\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), buf);
            }
        }

        close(acceptfd);
    }

    return 0;
}
复制代码

tcp最简单的客户端：

复制代码
int main(int argc, const char *argv[])
{
    int cfd = socket(PF_INET, SOCK_STREAM, 0);
    struct sockaddr_in cin;
    char buf[1024];

    cin.sin_family = PF_INET;
    cin.sin_port = htons(atoi(argv[2]));
    cin.sin_addr.s_addr = inet_addr(argv[1]);
    connect(cfd, (struct sockaddr *)&cin, sizeof(cin));

    printf("connect ip(%s) port(%s) server ok\n", argv[1], argv[2]);

    if(fork() == 0)
    {
        while(1)
        {
            bzero(buf, sizeof(buf));
            recv(cfd, buf, sizeof(buf), 0);
            printf("recv: %s\n", buf);
        }
    }

    while(1)
    {
        fgets(buf, sizeof(buf), stdin);
        buf[strlen(buf)-1] = '\0';
        send(cfd, buf, strlen(buf)+1, 0);
    }

    return 0;
}
复制代码

udp的最简单的服务器：

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int main(int argc, const char *argv[])
{
    int sfd;
    struct sockaddr_in sin, cin;
    char buf1[1024], buf2[1024], buf3[1024];
    socklen_t clen;
 
    sfd = socket(PF_INET, SOCK_DGRAM, 0);
 
    sin.sin_family = PF_INET;
    sin.sin_port = htons(atoi(argv[2]));
    sin.sin_addr.s_addr = inet_addr(argv[1]);
    bind(sfd, (struct sockaddr *)&sin, sizeof(sin));
 
    if(fork() == 0)
    {
        while(1)
        {
            clen = sizeof(cin);
            bzero(buf1, sizeof(buf1));
            recvfrom(sfd, buf1, sizeof(buf1), 0, (struct sockaddr *)&cin, &clen);
            printf("recvfrom: %s %d %s\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), buf1);
        }
    }
 
    while(1)
    {
        fscanf(stdin, "%s%s%s", buf1, buf2, buf3);
        cin.sin_family = PF_INET;
        cin.sin_port = htons(atoi(buf2));
        cin.sin_addr.s_addr = inet_addr(buf1);
        sendto(sfd, buf3, strlen(buf3)+1, 0, (struct sockaddr *)&cin, sizeof(cin));
    }
 
    return 0;
}

udp最简单的客户端：

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int main(int argc, const char *argv[])
{
    int sfd;
    struct sockaddr_in cin;
    char buf1[1024], buf2[1024], buf3[1024];
    socklen_t clen;
 
    sfd = socket(PF_INET, SOCK_DGRAM, 0);
 
    if(fork() == 0)
    {
        while(1)
        {
            clen = sizeof(cin);
            bzero(buf1, sizeof(buf1));
            recvfrom(sfd, buf1, sizeof(buf1), 0, (struct sockaddr *)&cin, &clen);
            printf("recvfrom: %s %d %s\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), buf1);
        }
    }
 
    while(1)
    {
        fscanf(stdin, "%s%s%s", buf1, buf2, buf3);
        cin.sin_family = PF_INET;
        cin.sin_port = htons(atoi(buf2));
        cin.sin_addr.s_addr = inet_addr(buf1);
        sendto(sfd, buf3, strlen(buf3)+1, 0, (struct sockaddr *)&cin, sizeof(cin));
    }
 
    return 0;
}

ftp最简单的服务器器：

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#define N 256
 
void list(int connectfd)
{
    DIR *dir;
    struct dirent *d;
    char buf[N];
 
    if((dir=opendir((const char *)get_current_dir_name())) == NULL)
    {
        perror("opendir");
        exit(1);
    }
    while((d=readdir(dir)) != NULL)
    {
        if(d->d_name[0] == '.')
        {
            continue;
        }
        strcpy(buf, d->d_name);
        send(connectfd, buf, N, 0);
    }
 
    closedir(dir);
}
 
void get(int connectfd, char *filename)
{
    char buf[N];
    FILE *fp;
    int n;
 
    if((fp=fopen(filename, "r")) == NULL)
    {
        strcpy(buf, "no");
        send(connectfd, buf, sizeof(buf), 0);
    }
 
    strcpy(buf, "yes");
    send(connectfd, buf, sizeof(buf), 0);
 
    while((n=fread(buf, 1, sizeof(buf), fp)) > 0)
    {
        send(connectfd, buf, n, 0);
    }
 
    fclose(fp);
}
 
void put(int connectfd, char *filename)
{
    char buf[N];
    FILE *fp;
    int n;
 
    if((fp=fopen(filename, "r")) == NULL)
    {
        strcpy(buf, "no");
        send(connectfd, buf, sizeof(buf), 0);
        fp = fopen(filename, "w");
        while((n=recv(connectfd, buf, sizeof(buf), 0)) > 0)
        {
            fwrite(buf, 1, n, fp);
        }
        fclose(fp);
 
        return;
    }
 
    strcpy(buf, "yes");
    send(connectfd, buf, sizeof(buf), 0);
}
 
int main(int argc, const char *argv[])
{
    FILE *fp;
    int n, listenfd, connectfd, i;
    struct sockaddr_in s, c;
    struct servent *sport;
    socklen_t clen;
    char *linep = NULL, buf[N], *arg[32];
 
    signal(SIGCHLD, SIG_IGN);
 
    if((fp=fopen("/etc/ftp.conf", "r")) == NULL)
    {
        perror("fopen");
        exit(1);
    }
 
    if(getline(&linep, &n, fp) == -1)
    {
        perror("getline");
        exit(0);
    }
    linep[strlen(linep)-1] = '\0';
    chdir(linep);
 
    if((sport=getservbyname("myftp", "tcp")) == NULL)
    {
        perror("getservbyname");
        exit(1);
    }
 
#ifdef DEBUG
    printf("%d %s\n", n, linep);
#endif
 
    if((listenfd=socket(PF_INET, SOCK_STREAM, 0)) == -1)
    {
        perror("socket");
        exit(1);
    }
     
    s.sin_family = PF_INET;
    s.sin_port = sport->s_port;
    s.sin_addr.s_addr = htonl(INADDR_ANY);
    if(bind(listenfd, (struct sockaddr *)&s, sizeof(s)) == -1)
    {
        perror("bind");
        exit(1);
    }
 
    listen(listenfd, 5);
 
    while(1)
    {
        clen = sizeof(c);
        if((connectfd=accept(listenfd, (struct sockaddr *)&c, &clen)) == -1)
        {
            perror("accept");
            exit(1);
        }
 
        if(fork() == 0)
        {
            close(listenfd);
 
            recv(connectfd, buf, sizeof(buf), 0);
 
            arg[0] = strtok(buf, " ");
            for(i=1; arg[i-1]!=NULL; i++)
            {
                arg[i]=strtok(NULL, " ");
            }
 
            if(strcmp(arg[0], "list") == 0)
            {
                list(connectfd);
            }
 
            if(strcmp(arg[0], "get") == 0)
            {
                get(connectfd, arg[1]);
            }
 
            if(strcmp(arg[0], "put") == 0)
            {
                put(connectfd, arg[1]);
            }
 
            close(connectfd);
            exit(0);
        }
 
        close(connectfd);
    }
}

　　

　　

ftp最简单的客户端器：

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#define N 256
 
void list(int connectfd)
{
    DIR *dir;
    struct dirent *d;
    char buf[N];
 
    if((dir=opendir((const char *)get_current_dir_name())) == NULL)
    {
        perror("opendir");
        exit(1);
    }
    while((d=readdir(dir)) != NULL)
    {
        if(d->d_name[0] == '.')
        {
            continue;
        }
        strcpy(buf, d->d_name);
        send(connectfd, buf, N, 0);
    }
 
    closedir(dir);
}
 
void get(int connectfd, char *filename)
{
    char buf[N];
    FILE *fp;
    int n;
 
    if((fp=fopen(filename, "r")) == NULL)
    {
        strcpy(buf, "no");
        send(connectfd, buf, sizeof(buf), 0);
    }
 
    strcpy(buf, "yes");
    send(connectfd, buf, sizeof(buf), 0);
 
    while((n=fread(buf, 1, sizeof(buf), fp)) > 0)
    {
        send(connectfd, buf, n, 0);
    }
 
    fclose(fp);
}
 
void put(int connectfd, char *filename)
{
    char buf[N];
    FILE *fp;
    int n;
 
    if((fp=fopen(filename, "r")) == NULL)
    {
        strcpy(buf, "no");
        send(connectfd, buf, sizeof(buf), 0);
        fp = fopen(filename, "w");
        while((n=recv(connectfd, buf, sizeof(buf), 0)) > 0)
        {
            fwrite(buf, 1, n, fp);
        }
        fclose(fp);
 
        return;
    }
 
    strcpy(buf, "yes");
    send(connectfd, buf, sizeof(buf), 0);
}
 
int main(int argc, const char *argv[])
{
    FILE *fp;
    int n, listenfd, connectfd, i;
    struct sockaddr_in s, c;
    struct servent *sport;
    socklen_t clen;
    char *linep = NULL, buf[N], *arg[32];
 
    signal(SIGCHLD, SIG_IGN);
 
    if((fp=fopen("/etc/ftp.conf", "r")) == NULL)
    {
        perror("fopen");
        exit(1);
    }
 
    if(getline(&linep, &n, fp) == -1)
    {
        perror("getline");
        exit(0);
    }
    linep[strlen(linep)-1] = '\0';
    chdir(linep);
 
    if((sport=getservbyname("myftp", "tcp")) == NULL)
    {
        perror("getservbyname");
        exit(1);
    }
 
#ifdef DEBUG
    printf("%d %s\n", n, linep);
#endif
 
    if((listenfd=socket(PF_INET, SOCK_STREAM, 0)) == -1)
    {
        perror("socket");
        exit(1);
    }
     
    s.sin_family = PF_INET;
    s.sin_port = sport->s_port;
    s.sin_addr.s_addr = htonl(INADDR_ANY);
    if(bind(listenfd, (struct sockaddr *)&s, sizeof(s)) == -1)
    {
        perror("bind");
        exit(1);
    }
 
    listen(listenfd, 5);
 
    while(1)
    {
        clen = sizeof(c);
        if((connectfd=accept(listenfd, (struct sockaddr *)&c, &clen)) == -1)
        {
            perror("accept");
            exit(1);
        }
 
        if(fork() == 0)
        {
            close(listenfd);
 
            recv(connectfd, buf, sizeof(buf), 0);
 
            arg[0] = strtok(buf, " ");
            for(i=1; arg[i-1]!=NULL; i++)
            {
                arg[i]=strtok(NULL, " ");
            }
 
            if(strcmp(arg[0], "list") == 0)
            {
                list(connectfd);
            }
 
            if(strcmp(arg[0], "get") == 0)
            {
                get(connectfd, arg[1]);
            }
 
            if(strcmp(arg[0], "put") == 0)
            {
                put(connectfd, arg[1]);
            }
 
            close(connectfd);
            exit(0);
        }
 
        close(connectfd);
    }
}

 

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