#!/usr/bin/env perl
#
# Because ifconfig output is... overly verbose.
#
# Output information from ifconfig -a like so:
#   interface:mtu ipv4/cidr mac_address ipv6_addr(if applicable)
#   ipv6 is not yet in place due to a: lazy, b: can't use it yet.
#

use strict;
use Socket;
use Sys::Hostname;
$ENV{'PATH'}='/sbin:/usr/sbin:/bin:/usr/bin';

my ($fqdn_regexp) = qr/([0-9,a-z,A-Z,\-,\_]+)\.([0-9,a-z,A-Z,\-,\_]+)\.(com|gov)/;

#
# converts a 1-word (4 byte) signed or unsigned integer into a dotted decimal
# ip address.
#
sub int2ip {
  my $n=int(pop);
  return(sprintf("%d.%d.%d.%d", ($n>>24)&0xff,($n>>16)&0xff,
    ($n>>8)&0xff,$n&0xff));
};

#
# Convert a host/ip/netmask/cidr/etc.... to a hash of information
# Example: host.domain.tld/24 will get the ip and calculate the netmask info
#  equally if host.domain.tld corresponds with 1.2.3.4 the following is valid
#  1.2.3.4/255.255.255.0 would obtain the same information.
#
# die()'s if anything isn't kosher.
#
# Ultra long function, probably needs to be looked at for condensing/splitting.
#
sub cidr2raw {
  my $rawinput = pop;
  my ($lhs, $rhs, $j, $uip) = (undef, undef, undef, undef);
  my ($ucidr) = 0;
  my ($network, $bits, $netmask, $broadcast, $low, $high);

  if ($rawinput =~ qr/(.*)\/(.*)/){
      $lhs = $1; $rhs = $2;
  }else{
    die "Input: $rawinput not expected.\n";
  };

  #
  # Handle ip/hostname for left hand side.
  if ($lhs =~ qr/(\d+)\.(\d+)\.(\d+)\.(\d+)/){
    foreach my $dotted (($1,$2,$3,$4)){
      if (($dotted > 255) or ($dotted < 0)){
        die "FATAL: ipv4 address entered, $lhs entered is impossible, $dotted is not between 0-255.\n";
      };
    };
    $uip = "$1.$2.$3.$4";
  };
  #
  # Handle the netmask/cidr for the right hand side,
  #
  # All input netmasks are converted to a cidr address for notation
  if ($rhs =~ qr/^(\d+)$/){ # /cidr
    $ucidr = $1;
    die "FATAL: Invalid CIDR <$ucidr>.$!\n" if (($ucidr > 32) or ($ucidr < 0));
  }elsif ($rhs =~ qr/(0[xX])?([0-9,a-f,A-F]{7})/){ # /0xhexnetmask
    my $trimmed = $2;
    my $insane = 0;
    foreach my $byte (split('', unpack("B32", pack("H*", $trimmed)))){
      ($byte) ? $ucidr++ : $insane++;
      die "FATAL: $rhs is not a valid hex netmask.$!\n" if ($insane and $byte);
    };
  }elsif ($rhs =~ qr/(\d+)\.(\d+)\.(\d+)\.(\d+)/){ # /255.255.255.0 form
    my @a = ($1, $2, $3, $4);
    my $insane = 0;
    foreach my $t (@a){
      die "FATAL: Netmask out of range. Input <$rhs> Invalid <$t>$!\n" if (($t < 0) or ($t > 255));
    };
    foreach my $byte (split('', unpack("B32", pack("C4", @a)))){
      ($byte) ? $ucidr++ : $insane++;
      die "FATAL: $rhs is not a valid netmask.$!\n" if ($insane and $byte);
    };
  }else{
    die "FATAL: Unknown or invalid netmask value entered. <$rhs>\n";
  };

  #
  # Network math GO! This is the meat of the function.
  my (@uip) = split(/\./, $uip);
  $network = 0;
  for ($j = 0; $j <= $#uip; $j++){
    $network += int($uip[$j])<<((3-$j)*8);
  };

  $bits = 0; $j = 0;
  for ($j = 31 - $ucidr; $j >= 0; $j--){
    $bits |= 1<<$j;
  };

  $netmask = 0xffffffff^$bits;
  $low = ($network&$netmask);
  $high = ($network&$netmask)+$bits-1;
  $broadcast = ($network&$netmask)|$bits;

  #
  # Throw the info back, they get a hash with zie info they may/may not need.
  # All up to the caller what they want to use.
  #
  return ("inet4" => $uip,
          "netmask" => int2ip($netmask),
          "broadcast" => int2ip($broadcast),
          "cidr" => $ucidr,
          "router" => int2ip($low+1),
          "network" => int2ip($low),
          "high" => int2ip($high),
          );
};

my @ifout;
if ($ENV{'TESTING'} ne '') {
    while(<>){
        chomp($_);
        last if ($_ eq '');
        push(@ifout, $_);
#        sleep 1;
#        print STDERR $_ . "\n";
    }
}else{
    open IFCONFIG, "ifconfig -a |";
    @ifout = <IFCONFIG>;
    close IFCONFIG;
}

# This seems wrong but it makes parsing easier due to solaris
# non root ifconfig not displaying the mac address. Reverse the output.
#
@ifout = reverse(@ifout);

my @output = ();

my ($ifname, $ifether, $ifmtu, $ifipv4, $ifnetmask, $ifipv6) = (undef,undef,undef,undef,undef,undef);
sub printiface{
  # assume a /32 if we don't know it
  unless (defined($ifnetmask)) {
    warn "$ifname has indeterminant netmask assuming /32\n";
    $ifnetmask = '32';
  }

  unless (defined($ifnetmask)) {
    $ifether = 'unknown';
  }

  unless ($ifname =~ m/lo.*/){
    my %netinfo = cidr2raw("$ifipv4\/$ifnetmask");
    $ifnetmask = $netinfo{"cidr"};
    $ifether = lc($ifether);
    my $line = sprintf "%-16s %-18s %-17s\n", "$ifname\@$ifmtu", "$ifipv4\/$ifnetmask", $ifether;
    push @output, $line;
  }

  # reset vars
  ($ifname, $ifether, $ifmtu, $ifipv4, $ifnetmask, $ifipv6) = (undef,undef,undef,undef,undef,undef);
};

foreach my $line (@ifout) {
  if ($line =~ /inet\s+(\d+[.]\d+[.]\d+[.]\d+)\s+/){
    $ifipv4 = $1;
  }
  if ($line =~ m/ether\s([:,0-9,a-f,A-F]{11,})/){
    $ifether =$1;
  }
  if ($line =~ m/^([\w,\:\d+]+)\s+.*HWaddr\s([:,0-9,a-f,A-F]{11,})/){
    $ifname = $1;
    $ifether = $2;
  }
  if ($line =~ m/^(.*)\:\s+.*mtu\s(\d+)/){
    $ifname = $1;
    $ifmtu = $2;
  }
  if ($line =~ m/MTU[:](\d+)/){
    $ifmtu = $1;
  }
  if ($line =~ m/inet\saddr\:(\d+[.]\d+[.]\d+[.]\d+)/){
    $ifipv4 = $1;
  }
  if ($line =~ m/netmask\s+(0[xX])?([a-f,A-F,0-9]{8})/){
    $ifnetmask = $2;
  }
  if ($line =~ m/Mask[:](\d+\.\d+\.\d+\.\d+)/){
    $ifnetmask = $1;
  }
  if ($line =~ m/netmask\s+(\d+[.]\d+[.]\d+[.]\d+)/){
    $ifnetmask = $1;
  }
  if ($line =~ m/netmask\s+0\s+broadcast/){
    $ifnetmask = '0';
  }

  print ":$ifether:$ifname:$ifmtu:$ifipv4:$ifnetmask:$ifipv6:\n" if ($ENV{'DEBUG'} ne '');
  printiface() if ($ifname and $ifmtu and $ifipv4 );
};

if (scalar(@output) < 1){
  warn "No interfaces? Scripts busted yo.\n";
}else{
  foreach my $line (reverse(@output)){
    print $line;
  }
}