#!/usr/bin/python2

# (c) 2016 by Siegrist(SystemLoesungen) <PSS @ ZweierNet.ch> 
# Website: [https://wiki.zweiernet.ch/wiki/Sinetstat]
# 
# This program is free software. 
#
# The program is based on a python netstat script that was written by da667 available on https://github.com/da667/netstat
# who had it adapted from Ricardo Pascal, available on http://voorloopnul.com/blog/a-python-netstat-in-less-than-100-lines-of-code.
#
# This version has some improvements make it an acceptable alternative to the original netstat command.
# So it can explore IPv4 in IPv6 listening sockets and some other information over and above the original netstat.
#
# Simply try: 'sinetstat -h'
#


import pwd
import os
import re
import glob
import socket
import sys
import string
import fcntl
import struct
import argparse



VERSION = '1.01'

PROC_TCP4 = "/proc/net/tcp"
PROC_UDP4 = "/proc/net/udp"
PROC_TCP6 = "/proc/net/tcp6"
PROC_UDP6 = "/proc/net/udp6"

MAX_IPV4_ADDRESS = 0xffffffff
MAX_IPV6_ADDRESS = 0xffffffffffffffffffffffffffffffff
TCP_STATE = {
        '01':'ESTABLISHED',
        '02':'SYN_SENT',
        '03':'SYN_RECV',
        '04':'FIN_WAIT1',
        '05':'FIN_WAIT2',
        '06':'TIME_WAIT',
        '07':'CLOSE',
        '08':'CLOSE_WAIT',
        '09':'LAST_ACK',
        '0A':'LISTEN',
        '0B':'CLOSING'
        }

v4ports = []
opt_l = True



def grep_b(list, search):
    return [True for i in list if search in i]
    
def get_ip_address(ifname):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    return socket.inet_ntoa(fcntl.ioctl(
        s.fileno(),
        0x8915,  # SIOCGIFADDR
        struct.pack('256s', ifname[:15])
    )[20:24])

def _tcp4load():
    ''' Read the table of tcp connections & remove the header  '''
    with open(PROC_TCP4,'r') as f:
        content = f.readlines()
        content.pop(0)
    return content

def _tcp6load():
    ''' Read the table of tcpv6 connections & remove the header'''
    with open(PROC_TCP6,'r') as f:
        content = f.readlines()
        content.pop(0)
    return content

def _udp4load():
    '''Read the table of udp connections & remove the header '''
    with open(PROC_UDP4,'r') as f:
        content = f.readlines()
        content.pop(0)
    return content

def _udp6load():
    '''Read the table of udp connections & remove the header '''
    with open(PROC_UDP6,'r') as f:
        content = f.readlines()
        content.pop(0)
    return content

def _hex2dec(s):
    return str(int(s,16))

def _ip(s):
    ip = [(_hex2dec(s[6:8])),(_hex2dec(s[4:6])),(_hex2dec(s[2:4])),(_hex2dec(s[0:2]))]
    return '.'.join(ip)

def _ip6(s):
    ip = [s[6:8],s[4:6],s[2:4],s[0:2],s[12:14],s[14:16],s[10:12],s[8:10],s[22:24],s[20:22],s[18:20],s[16:18],s[30:32],s[28:30],s[26:28],s[24:26]]
    #print '66666:', ':'.join(ip), s
    return ':'.join(ip)

def _ip6q(s):
    ip = [s[6:8]+s[4:6],s[2:4]+s[0:2],s[12:14]+s[14:16],s[10:12]+s[8:10],s[22:24]+s[20:22],s[18:20]+s[16:18],s[30:32]+s[28:30],s[26:28]+s[24:26]]
    #print '666qqq:', ':'.join(ip), s
    return ':'.join(ip)

def _conv_v6(s):
    return s
	
	

def _remove_empty(array):
    return [x for x in array if x !='']

def _convert_ipv4_port(array):
    host,port = array.split(':')
    return _ip(host),_hex2dec(port)

def _convert_ipv6_port(array):
    host,port = array.split(':')
    return _ip6(host),_hex2dec(port)

def _convert_ipv6(array):
    host,port = array.split(':')
    return _ip6q(host)
    
def _addr_normal(s):
    return ':'.join(["%x" % x for x in [int(x, 16) for x in s.split(':')]])
    
def _countFollowingZeros(l):
    """Return number of elements containing 0 at the beginning of the list."""
    #print 'aaa:', l
    if len(l) == 0:
        return 0
    elif l[0] != 0:
        return 0
    else:
        return 1 + _countFollowingZeros(l[1:])

def _compress_v6(addr):
    hextets = [int(x, 16) for x in addr.split(':')]
    #print hextets
    followingzeros = [0] * 8
    for i in xrange(len(hextets)):
        followingzeros[i] = _countFollowingZeros(hextets[i:])
    # compressionpos is the position where we can start removing zeros
    compressionpos = followingzeros.index(max(followingzeros))
    if max(followingzeros) > 1:
        # genererate string with the longest number of zeros cut out
        # now we need hextets as strings
        hextets = [x for x in _addr_normal(addr).split(':')]
        while compressionpos < len(hextets) and hextets[compressionpos] == '0':
            del(hextets[compressionpos])
        hextets.insert(compressionpos, '')
        if compressionpos + 1 >= len(hextets):
            hextets.append('')
        if compressionpos == 0:
            hextets = [''] + hextets
        return ':'.join(hextets)
    else:
        return _addr_normal(addr)


def _resolve_ip(host):
    """
    resolve ip und update dictionary res_cache {'ip': 'name'}.
    If resolution for a ip failed, 'name' is n_try ... 0.
    """
    try:
        hname = socket.gethostbyaddr(host)[0]
        return str(hname)
    except:
        return str(host)
    
    
    
    
def netstat_tcp4():
    '''
    Function to return a list with status of tcp4 connections on Linux systems.
    '''

    tcpcontent =_tcp4load()
    tcpresult = []
    for line in tcpcontent:
        line_array = _remove_empty(line.split(' '))     # Split lines and remove empty spaces.
        l_host,l_port = _convert_ipv4_port(line_array[1]) # Convert ipaddress and port from hex to decimal.
        r_host,r_port = _convert_ipv4_port(line_array[2])
        tcp_id = line_array[0]
        state = TCP_STATE[line_array[3]]
        if state != 'LISTEN' and o_listen == True:
            continue
        if ( state == 'LISTEN' or state == 'SYN_SENT' or state == 'SYN_RECV' ) and o_estab == True:
            continue
            
        try:
            uid = pwd.getpwuid(int(line_array[7]))[0]       # Get user from UID.
        except:
            uid = line_array[7]
        inode = line_array[9]                           # Need the inode to get process pid.
        if int(inode) > 0:
            pid = _get_pid_of_inode(inode)
            try:                                            # try read the process name.
                if o_wide == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00')).split(' ')[0]
                elif o_wider == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00'))
                else:
                    exe = os.readlink('/proc/'+pid+'/exe').split('/')[-1]
            except:
                exe = '-'
        else:
            pid = '-'
            exe = '-'
        
        if o_numeric == False:
            r_host = _resolve_ip(r_host)
        
        nline = '%-7s %-24s  %-24s  %-11s  %-8s  %-6s  %-s' % ('TCP4', l_host+': '+l_port, r_host+': '+r_port, state, uid, pid, exe)
        
        tcpresult.append(nline)
        
        # update v4inv6check list
        v4ports.append(l_port)
        
    return tcpresult

def netstat_tcp6():
    '''
    This function returns a list of tcp connections utilizing ipv6. 
    '''
    tcpcontent = _tcp6load()
    tcpresult = []
    for line in tcpcontent:
        line_array = _remove_empty(line.split(' '))
        l_host,l_port = _convert_ipv6_port(line_array[1])
        r_host,r_port = _convert_ipv6_port(line_array[2])
        tcp_id = line_array[0]
        state = TCP_STATE[line_array[3]]
        if state != 'LISTEN' and o_listen == True:
            continue
        if ( state == 'LISTEN' or state == 'SYN_SENT' or state == 'SYN_RECV' ) and o_estab == True:
            continue
            
        try:
            uid = pwd.getpwuid(int(line_array[7]))[0]       # Get user from UID.
        except:
            uid = line_array[7]
        inode = line_array[9]
        if int(inode) > 0:
            pid = _get_pid_of_inode(inode)
            try:                                            # try read the process name.
                if o_wide == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00')).split(' ')[0]
                elif o_wider == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00'))
                else:
                    exe = os.readlink('/proc/'+pid+'/exe').split('/')[-1]
            except:
                exe = '-'
        else:
            pid = '-'
            exe = '-'

        nline = '%-7s %-24s  %-24s  %-11s  %-8s  %-6s  %-s' % ('TCP6', _compress_v6(_convert_ipv6(line_array[1]))+': '+l_port, _compress_v6(_convert_ipv6(line_array[2]))+': '+r_port, state, uid, pid, exe)
        
        tcpresult.append(nline)
        	
    return tcpresult


def netstat_tcp4in6():
    '''
    Returns a list of tcp ipv4 in ipv6 listen sockets.
    '''    
    #print xx()
    
    tcpcontent = _tcp6load()
    tcpresult = []
    for line in tcpcontent:
        line_array = _remove_empty(line.split(' '))
        #if TCP_STATE[line_array[3]] != 'LISTEN':
        #	continue
        
        l_host,l_port = _convert_ipv6_port(line_array[1])
        r_host,r_port = _convert_ipv6_port(line_array[2])
        if grep_b(v4ports,l_port):
            continue
        tcp_id = line_array[0]
        state = TCP_STATE[line_array[3]]
        if state != 'LISTEN' and o_listen == True:
            continue
        if ( state == 'LISTEN' or state == 'SYN_SENT' or state == 'SYN_RECV' ) and o_estab == True:
            continue
                
        try:
            uid = pwd.getpwuid(int(line_array[7]))[0]       # Get user from UID.
        except:
            uid = line_array[7]
        inode = line_array[9]
        if int(inode) > 0:
            pid = _get_pid_of_inode(inode)
            try:                                            # try read the process name.
                if o_wide == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00')).split(' ')[0]
                elif o_wider == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00'))
                else:
                    exe = os.readlink('/proc/'+pid+'/exe').split('/')[-1]
            except:
                exe = '-'
        else:
            pid = '-'
            exe = '-'
            
        if l_host == '00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:01':
        	if _check_v4inv6_port("127.0.0.1",l_port):
        	    nline = '%-7s %-24s  %-24s  %-11s  %-8s  %-6s  %-s' % ('TCP4in6', '127.0.0.1: '+l_port, _compress_v6(_convert_ipv6(line_array[2]))+': '+r_port, state, uid, pid, exe)
        	    tcpresult.append(nline)
        if l_host == "00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00":
        	if _check_v4inv6_port("0.0.0.0",l_port):
        	    nline = '%-7s %-24s  %-24s  %-11s  %-8s  %-6s  %-s' % ('TCP4in6', '0.0.0.0: '+l_port, _compress_v6(_convert_ipv6(line_array[2]))+': '+r_port, state, uid, pid, exe)
        	    tcpresult.append(nline)
        #else:
        #    for a in MYIFS.split():
        #       _check_v4inv6_port(get_ip_address(a),l_port) 
        
    return tcpresult


def netstat_udp4():
    '''
    Function to return a list with status of udp connections.
    '''

    udpcontent =_udp4load()
    udpresult = []
    for line in udpcontent:
        line_array = _remove_empty(line.split(' '))
        l_host,l_port = _convert_ipv4_port(line_array[1])
        r_host,r_port = _convert_ipv4_port(line_array[2])
        udp_id = line_array[0]
        udp_state = TCP_STATE[line_array[3]]
        if ( udp_state != 'ESTABLISHED' and o_estab == True ) or o_estab == False:
            continue
        if udp_state != 'ESTABLISHED':
            udp_state =' ' #UDP is stateless
        try:
            uid = pwd.getpwuid(int(line_array[7]))[0]       # Get user from UID.
        except:
            uid = line_array[7]
        inode = line_array[9]
        if int(inode) > 0:
            pid = _get_pid_of_inode(inode)
            try:                                            # try read the process name.
                if o_wide == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00')).split(' ')[0]
                elif o_wider == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00'))
                else:
                    exe = os.readlink('/proc/'+pid+'/exe').split('/')[-1]
            except:
                exe = '-'
        else:
            pid = '-'
            exe = '-'

        nline = '%-7s %-24s  %-24s  %-11s  %-8s  %-6s  %-s' % ('UDP4', l_host+': '+l_port, r_host+': '+r_port, udp_state, uid, pid, exe)
        
        udpresult.append(nline)
    return udpresult

def netstat_udp6():
    '''
    Function to return a list of udp connection utilizing ipv6
    '''

    udpcontent =_udp6load()
    udpresult = []
    for line in udpcontent:
        line_array = _remove_empty(line.split(' '))
        l_host,l_port = _convert_ipv6_port(line_array[1])
        r_host,r_port = _convert_ipv6_port(line_array[2])
        udp_id = line_array[0]
        udp_state = TCP_STATE[line_array[3]]
        if ( udp_state != 'ESTABLISHED' and o_estab == True ) or o_estab == False:
            continue
        if udp_state != 'ESTABLISHED':
            udp_state =' ' #UDP is stateless
        try:
            uid = pwd.getpwuid(int(line_array[7]))[0]       # Get user from UID.
        except:
            uid = line_array[7]
        inode = line_array[9]
        if int(inode) > 0:
            pid = _get_pid_of_inode(inode)
            try:                                            # try read the process name.
                if o_wide == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00')).split(' ')[0]
                elif o_wider == True:
                    with open('/proc/'+pid+'/cmdline','r') as f:
                        exe = ' '.join(f.read().split('\x00'))
                else:
                    exe = os.readlink('/proc/'+pid+'/exe').split('/')[-1]
            except:
                exe = '-'
        else:
            pid = '-'
            exe = '-'

        nline = '%-7s %-24s  %-24s  %-11s  %-8s  %-6s  %-s' % ('UDP6', _compress_v6(_convert_ipv6(line_array[1]))+': '+l_port, _compress_v6(_convert_ipv6(line_array[2]))+': '+r_port, udp_state, uid, pid, exe)
        
        udpresult.append(nline)
    return udpresult


def _get_pid_of_inode(inode):
    '''
    To retrieve the process pid, check every running process and look for one using
    the given inode.
    '''
    for item in glob.glob('/proc/[0-9]*/fd/[0-9]*'):
        try:
            if re.search(inode,os.readlink(item)):
                return item.split('/')[2]
        except:
            pass
    return None
    
def check_root():
    if os.getuid() == 0:
        return True
    else:
        return False
    
def _check_v4inv6_port(addr,portnr):
    '''
    check if a v4 port is listening over ip6. Strange, we do a SYN connect for every port not listening v4.
    thats because I think there is no image in the /proc filesystem
    '''
    #print 'aaacc:', addr, portnr
    is_onnected = False
    try:
        try:
            t_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        except:
            print("Error: Can't open socket!\n")
            return False
        t_socket.connect((addr, int(portnr)))
        is_onnected = True
    except:
        is_onnected = False    
    finally:
        if(is_onnected and portnr != t_socket.getsockname()[1]):
            #print("{}:{} Open \n".format(addr, portnr))
            t_socket.close()
            return True
        t_socket.close()
        return False


if __name__ == '__main__':
    if not check_root():
        print("This program needs root privileges !\nThats because of reading the /proc filesystem and using functions like getpwuid().\nSo I give up\n")
        sys.exit()
    
    
    #print
    # commandline params
    o_numeric = True
    o_listen = False
    o_estab = None
    o_wide = False
    o_wider = False
    o_udp = True
    o_tcp = True
    o_v6 = True
    o_v4 = True
    parser = argparse.ArgumentParser(description='netstat utility V'+VERSION+"\n2017 by sigi <https://wiki.zweiernet.ch/wiki/sinetstat>",
                                   formatter_class=argparse.RawDescriptionHelpFormatter )
    parser.add_argument('-l', help="Only listening sockets", action="store_true")
    parser.add_argument('-e', help="Only established sockets", action="store_true")
    parser.add_argument('-r', help="Resolve IP-Addresses", action="store_true")
    parser.add_argument('-w', help="Wide (show cmd)", action="store_true")
    parser.add_argument('-W', help="Wider (show cmd with arguments)", action="store_true")
    parser.add_argument('-t', help="Only TCP", action="store_true")
    parser.add_argument('-u', help="Only UDP", action="store_true")
    parser.add_argument('-4', dest='v4', help="Only IPv4", action="store_true")
    parser.add_argument('-6', dest='v6', help="Only IPv6", action="store_true")
    args = parser.parse_args()
    if args.r:
        o_numeric = False
    if args.l:
        o_listen = True
    if args.e:
        o_estab = True
        o_listen = False
    if args.w:
        o_wide = True
    if args.W:
        o_wider = True
        o_wide = False
    if args.t:
        o_udp = False 
    if args.u:
        o_tcp = False
    if args.v4:
        o_v6 = False
    if args.v6:
        o_v4 = False
    
    
    # Output
    print '%-7s %-24s  %-24s  %-11s  %-8s  %-6s  %-s' % ('Proto', 'Local Address', 'Remote Address', 'State', 'UID', 'PID', 'Program')
    print '%-7s %-24s  %-24s  %-11s  %-8s  %-6s  %-s' % ('-----', '-------------', '--------------', '-----', '---', '---', '-------')
    #print "\nTCP (v4) Results:\n"
    if o_v4 == True and o_tcp == True: 
        for conn_tcp in netstat_tcp4():
            print conn_tcp
    #print "\nTCP (v4inv6) Results:\n"
    if o_v4 == True and o_tcp == True:
        for conn_tcp46 in netstat_tcp4in6():
            print conn_tcp46
    #print "\nTCP (v6) Results:\n"
    if o_v6 == True and o_tcp == True:
        for conn_tcp6 in netstat_tcp6():
            print conn_tcp6
    #print "\nUDP (v4) Results:\n"
    if o_v4 == True and o_udp == True and not args.l:
        for conn_udp in netstat_udp4():
            print conn_udp
    #print "\nUDP (v6) Results:\n"
    if o_v6 == True and o_udp == True and not args.l:
        for conn_udp6 in netstat_udp6():
            print conn_udp6