1  import socket
 2  import os
 3  import random
 4  import string
 5  
 6  from . import sam
 7  
 8  def get_free_port():
 9      """Get a free port on your local host"""
10      s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
11      s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
12      s.bind(('', 0))
13      free_port = s.getsockname()[1]
14      s.close()
15      return free_port
16  
17  def is_address_accessible(address):
18      """Check if address is accessible or down"""
19      s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
20      is_accessible = s.connect_ex(address) == 0
21      s.close()
22      return is_accessible
23  
24  def address_from_string(address_string):
25      """Address tuple from host:port string"""
26      address = address_string.split(":")
27      return (address[0], int(address[1]))
28  
29  def get_sam_address():
30      """
31      Get SAM address from environment variable I2P_SAM_ADDRESS, or use a default
32      value
33      """
34      value = os.getenv("I2P_SAM_ADDRESS")
35      return address_from_string(value) if value else sam.DEFAULT_ADDRESS
36  
37  def generate_session_id(length=6):
38      """Generate random session id"""
39      rand = random.SystemRandom()
40      sid = [rand.choice(string.ascii_letters) for _ in range(length)]
41      return "reticulum-" + "".join(sid)
42