[Click] Help, about handler

[wubaochuan]

Hi Beyers, Cliff,
        Thank you for all your help.
        I can telnet Click's ControlSocket.
        Now I can connect to Click's element ControlSocket with a C 
program. I summarize the solution of my problem, maybe it is helpful to 
other newbies like me.
        First I run /*click test.click*/, and then run the C program 
/*client.c*/. The following is test.click and client.c.



test.click,
================start of test.click ==================
ControlSocket("TCP", 1234);
is::InfiniteSource(DATA \<00 00 c0 ae 67 ef  00 00 00 00 00 00  08 00
45 00 00 28  00 00 00 00  40 11 77 c3  01 00 00 01
02 00 00 02  13 69 13 69  00 14 d6 41  55 44 50 20
70 61 63 6b  65 74 21 0a>)//, LIMIT 5, STOP true)
    -> Strip(14)
    -> Align(4, 0)    // in case we're not on x86
    -> CheckIPHeader(BADSRC 18.26.4.255 2.255.255.255 1.255.255.255)
        -> Print(ok)
    -> Discard;
================end of test.click   ==================


client.c, a simple tcp client.
================start of client.c ===================
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>


int main()
{

    char buf[BUFSIZ];
    char bytes[20];
    int sockfd;
    int len;
    struct sockaddr_in address;
    int result;

    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd == -1)
    {
        perror("socket() error");
        exit(1);
    }

    address.sin_family = AF_INET;
    inet_pton(AF_INET, "10.3.16.138", &address.sin_addr.s_addr); // 
10.3.16.138 is IP of the machine which Click running on. You may change 
it to proper IP.
    address.sin_port = htons(1234); // Click's ControlSocket's port
    len = sizeof(address);

    result = connect(sockfd, (struct sockaddr *)&address, len);

    if (result == -1)
    {
        perror("connect() error");
        exit(1);
    }
    else
    {
       printf("connect success\n");
    }

    FILE *controlfile = fdopen(sockfd, "r+");
    fgets(buf, sizeof(buf)-1, controlfile);//  get 
"Click::ControlSocket/1.3"
    fputs("read is.count\n", controlfile); //  just as you input "read 
is.count" when telnet Click.
    fgets(buf, sizeof(buf)-1, controlfile);//  get "200 Read handler 
'is.count' OK"
    fgets(buf, sizeof(buf)-1, controlfile);//  get "DATA 7", "7" means 
there is 7 bytes more. maybe you can get other number, such as 6.
    sscanf(buf, "%*s%s", bytes); // put "7" into bytes[]
    fread(buf, sizeof(char), atoi(bytes), controlfile);// get the 
following 7B, which is the result of "read is.count"
    printf("%s\n", buf);

    close(sockfd);
    fclose(controlfile);
    return 0;
}

================end of client.c  ====================

After I run /*click test.click*/, the click process is listening on port 
1234, I can examine this using the following command: netstat -ntlp | 
grep 1234,
On my machine, the above command yields: tcp        0      0 
0.0.0.0:1234            0.0.0.0:*               LISTEN      9987/click
And then, I can telnet click using : /*telnet 10.3.16.138 1234, */just 
as the following:

root at wubaochuan-desktop:~# telnet 10.3.16.138 1234
Trying 10.3.16.138...
Connected to 10.3.16.138.
Escape character is '^]'.
Click::ControlSocket/1.3
read is.count
200 Read handler 'is.count' OK
DATA 8
13283904read is.count
200 Read handler 'is.count' OK
DATA 8
13341696
write is.reset
200 Write handler 'is.reset' OK
read is.count
200 Read handler 'is.count' OK
DATA 5
57792
quit
200 Goodbye!
Connection closed by foreign host.
root at wubaochuan-desktop:~#




Then I compiled client.c, and run it, I can get result of "read is.count".
ps: /*Unix network programming*/ is a good book. I am using Ubuntu 9.10 
Linux, the compiler is gcc4.4.1.




Thank you.


Yours
Chuan