[C] Open /proc/net/tcp then detect the specific word

[C] Open /proc/net/tcp then detect the specific word



#include <stdio.h>

#include <stdlib.h>



#define  TEMP_BUFFER_SIZE 0x10000

/*

   This function return a TCP port state.



   The function use '/proc/net/tcp' file and parse it.



   Example of /proc/net/tcp file that we are going to parse:

   sl local_address rem_address   st tx_queue rx_queue tr tm->when retrnsmt   uid  timeout inode

   0: C0A8FEFD:006F 00000000:0000 0A 00000000:00000000 00:00000000 00000000   0    0        542  1 7e109620 300 0 0 2 -1

   1: 7F000001:006F 00000000:0000 0A 00000000:00000000 00:00000000 00000000   0    0        541  1 7e109a80 300 0 0 2 -1

   2: C0A8FEFD:EA1B 00000000:0000 0A 00000000:00000000 00:00000000 00000000   0    0        556  1 7e1091c0 300 0 0 2 -1

   3: C0A8FEFD:EA1B C0A8FEFE:03E3 01 00000000:00000000 00:00000000 00000000   0    0        562  1 7e1084a0 21 0 0 10 -1

   4: C0A8FEFD:033A C0A8FEFE:C73A 01 00000000:00000000 00:00000000 00000000   0    0        1724 1 7e108d60 21 0 0 10 -1

   5: C0A8FEFD:1A04 C0A8FEFE:9223 06 00000000:00000000 03:00001682 00000000   0    0        0    3 7c0e2820



   The 'st' column is the State of the connection (return value of function):

    0:  ???

    1:  ESTABLISHED

    2:  SYN_SENT

    3:  SYN_RECV

    4:  FIN_WAIT1

    5:  FIN_WAIT2

    6:  TIME_WAIT

    7:  CLOSE

    8:  CLOSE_WAIT

    9:  LAST_ACK

    10: LISTEN

    11: CLOSING

*/

int main()

{

    char line_buffer[ TEMP_BUFFER_SIZE ];

    FILE *fp;

    int num;

    unsigned int local_address_ip;

    unsigned int rem_address_ip;

    unsigned int local_address_port;

    unsigned int rem_address_port;

    unsigned int line_id;

    unsigned int conn_state;



    /* Open the mtd file */

    if((fp=fopen( "/proc/net/tcp", "r" )) == NULL)

    {

        return 0;

    }



    /* Read first line of titles - ignored*/

    if (fgets( line_buffer, TEMP_BUFFER_SIZE-1, fp ) == NULL)

    {

        fclose( fp );

        return 0;

    }



    /* Read the file line by line*/

    while ( fgets( line_buffer, TEMP_BUFFER_SIZE-1, fp ) )

    {

        num = sscanf(line_buffer,"%d: %X:%X %X:%X %X",&line_id,&local_address_ip,&local_address_port,&rem_address_ip,&rem_address_port,&conn_state);



        printf("num (%d) line_buffer = %s\n",num,line_buffer);

        printf("line_id (0x%X),  local_address_ip (0x%X) ,  local_address_port (0x%X),   rem_address_ip (0x%X),  rem_address_port (0x%X),   conn_state (0x%X)\n\n",line_id,  local_address_ip,  local_address_port,   rem_address_ip,  rem_address_port,   conn_state);



        if (num < 6)

        {

            fclose( fp );

            return -1;

        }

        if (local_address_port == "0xAB19")

        {

            fclose( fp );

            return 1;

        }

    }



    /* close '/proc' file */

    fclose( fp );



    return 0;

}