NetAddr::IP Automated Subnet Allocation

amt has asked for the wisdom of the Perl Monks concerning the following question:

Gentlemen,

I am using NetAddr::IP to break down a range of addresses given, the base address, the stop address, and the subnet mask, in bit format.
The problem that I am having is with getting the address that is 1 higher than the broadcast address for the previous subnet work. Below you will see code, with comments inline.

sub subnet_recurse {

my $netaddr_ref = shift;
my $endaddr_ref = shift;
my $new_addmask;
[download]

The parameters are references to NetAddr::IP objects

print "<hr><b>base: " . $$netaddr_ref->network() "</b><br>";
my $hostnum = 0;

foreach ($$netaddr_ref->hostenum()){
 print "add$hostnum: " . $_ ."<br>";
 $hostnum++;
 }
print "<b>brdc:".$$netaddr_ref->broadcast()."</b><br><hr>";
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Print out the stuff that is given to me from the objects.

my $net_broadcast =  
 NetAddr::IP->new($$netaddr_ref->broadcast()->addr());
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Create new NetAddr::IP ojbect with the broadcast ip address

my $new_netaddr=NetAddr::IP->new($net_broadcast->addr())+1;
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Use overloaded "+" as defined by the specification

print "<b>brd: " . $net_broadcast->addr() ."</b><br>";

#print "<b>new: " . $new_netaddr->addr() . "</b><br>";
#if( $new_netaddr->within($$endaddr_ref) ){
#       subnet_recurse( \$new_netaddr, $endaddr_ref );
#} else { return; }
return;
}
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The resulting output is as follows:

host: 192.168.1.0/29
mask: 255.255.255.248
base: 192.168.1.0/29
add0: 192.168.1.1/32
add1: 192.168.1.2/32
add2: 192.168.1.3/32
add3: 192.168.1.4/32
add4: 192.168.1.5/32
add5: 192.168.1.6/32
brdc: 192.168.1.7/29
192.168.1.7/32brd: 192.168.1.7
[download]

This has held me up all day, and is starting to become frustrating. Thanks for any help in advance.

amt

Comment on NetAddr::IP Automated Subnet Allocation Select or Download Code

Replies are listed 'Best First'.
Re: NetAddr::IP Automated Subnet Allocation by ikegami (Patriarch) on Sep 02, 2004 at 22:49 UTC
Like the documentation indicates says + and ++ will wrap around within the subnet, so new_netaddr won't hold what you want: `(127.0.0.255/24)++ -> (127.0.0.0/24) (127.0.0.255/24)+1 -> (127.0.0.0/24)` [download] How about: (Tested) `my ($addr, $mask) = $net_broadcast->numeric(); my $new_netaddr = NetAddr::IP->new($addr+1, $mask);` [download] I haven't looked at why you have /32's instead of /29's in your output.	[reply] [d/l] [select]
Re^2: NetAddr::IP Automated Subnet Allocation by amt (Monk) on Sep 03, 2004 at 15:00 UTC
Your solution works, but I need to add 1 to the address of the broadcast address, so I can begin the next sub-network. Your solution returns the numberic() of the current address field, which is the base network address. amt	[reply]
Re^3: NetAddr::IP Automated Subnet Allocation by ikegami (Patriarch) on Sep 03, 2004 at 15:18 UTC
Your solution returns the numberic() of the current address field, which is the base network address. Not so. Did you type in `$net_addr` where you should have typed `$net_broadcast`? `use NetAddr::IP (); my $net_addr = NetAddr::IP->new('192.168.1.0/29'); my $net_broadcast = $net_addr->broadcast(); my $net_newaddr; { my ($addr, $mask) = $net_broadcast->numeric(); $net_newaddr = NetAddr::IP->new($addr+1, $mask); } print("$net_addr\n"); # prints 192.168.1.0/29 print("$net_broadcast\n"); # prints 192.168.1.7/29 print("$net_newaddr\n"); # prints 192.168.1.8/29` [download]	[reply] [d/l] [select]
Re: NetAddr::IP Automated Subnet Allocation by NetWallah (Canon) on Sep 03, 2004 at 01:48 UTC
Bravo ! ikegami's code works (++). Here is my minor variation: `my $IP2 = NetAddr::IP->new($IP1->broadcast->numeric()+1 , 24); # Usin +g 24-bit mask...` [download] What I'm curious about is why you pass Object REFEREENCES around, causing awkward syntax like $$netaddr_ref->hostenum()) Why not pass the object itself (Which happens to be a reference already) ? Earth first! (We'll rob the other planets later)	[reply] [d/l]
Re^2: NetAddr::IP Automated Subnet Allocation by amt (Monk) on Sep 03, 2004 at 13:08 UTC
i was passing references because of a previous misconception mixed with laziness. haha. thanks for the suggestions you two, it has already made my otherwise miserable hungover day, just a little bit better. like a ray of sunshine cutting through my drunken stupor, but I digress. amt	[reply]