Implement a small program that reads /proc/net/tcp every 10 seconds and outputs any new connections.
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105 lines
2.8 KiB

package main
import (
"reflect"
//"./timer"
"time"
"fmt"
"strings"
"regexp"
"io/ioutil"
"encoding/hex"
)
var tcp_data string = read_tcp_file("/proc/net/tcp")
func main() {
var loops int = 0
// How to split on space-delimited fields, then colon-delimited fields?
// How to turn this byte into a string?
// /proc/net/tcp hex addresses need to be reversed two-character-wise
// and then converted byte by byte (2 char at a time)
//fmt.Println(convert_address(reverse_string(reverse_bytes("0100007F"))))
for _ = range time.Tick(10 * time.Second) {
fmt.Println("Waiting 10 seconds...")
for num, row := range get_tcp_rows(tcp_data) {
row_type := reflect.TypeOf(row)
fmt.Println(num, " ", row_type)
}
// if loops modulo 6 (1min) then
// for address in address_list do
// if (grep address address_list | wc -l >=3) then
// This is a port scan!
// fi
// done
// elseif (wc -l old_tcp_file < wc -l tcp_file) then
// for i in (wc -l tcp_file - wc -l old_tcp_flle) do
// print New Connection! reverse_strng(reverse_bytes(tcp_file[i])) // This oversimplifies row value selection for the sake
// // of pseudocode
// done
// else
// "No new connections. Waiting another 10 seconds..."
// fi
loops++
}
}
func check(e error) {
if e != nil {
panic(e)
}
}
// Aiming for an array of [string]string maps
// Am I looking for a map[string]interface here?
func get_tcp_rows(connections_file string) []string {
tcp_lines := strings.Split(connections_file, "\n")
regexpression := regexp.MustCompile(`[\r\n\t\f\v]+`)
tcp_columns := regexpression.Split(tcp_lines[0], -1)
var tcp_values map[string]string
for i, line := range tcp_lines[1:] {
trim_line := strings.TrimSpace(line)
values := regexpression.Split(trim_line, -1)
column := tcp_columns[i]
tcp_values[column] = values
}
return tcp_values
}
// Take a string, create a rune slice, and use a loop to reverse it character-wise.
func reverse_bytes(s string) string {
runes := []rune(s)
for i, j := len(runes)-2, len(runes)-1; j > 0; i, j = i-2, j-2 {
runes[i], runes[j] = runes[j], runes[i]
}
return string(runes)
}
func reverse_string(s string) string {
runes := []rune(s)
for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
runes[i], runes[j] = runes[j], runes[i]
}
return string(runes)
}
// Store data function
// Loads all fields and subfields into storage (memory? where?)
// State check function
// hash each line, use to determine new lines, convert to readable, and print
func convert_address(address string) []byte {
output, err := hex.DecodeString(address)
check(err)
return output
}
func read_tcp_file(connections_file_path string) string {
data, err := ioutil.ReadFile(connections_file_path)
check(err)
fmt.Println("Data file read successfully.\n")
return string(data)
}