Provided by: libnet-traceroute-pureperl-perl_0.10-1_all 
NAME
Net::Traceroute:PurePerl - traceroute(1) functionality in perl via raw sockets
VERSION
This document describes version 0.10 of Net::Traceroute::PurePerl.
SYNOPSIS
use Net::Traceroute::PurePerl;
my $t = new Net::Traceroute::PurePerl(
backend => 'PurePerl', # this optional
host => 'www.openreach.com',
debug => 0,
max_ttl => 12,
query_timeout => 2,
packetlen => 40,
protocol => 'udp', # Or icmp
);
$t->traceroute;
$t->pretty_print;
DESCRIPTION
This module implements traceroute(1) functionality for perl5. It allows you to trace the
path IP packets take to a destination. It is implemented by using raw sockets to act just
like the regular traceroute.
You must also be root to use the raw sockets.
INSTALLATION
Basic Installation
Net::Traceroute::PurePerl may be installed through the CPAN shell in the usual CPAN shell
manner. This typically is:
$ perl -MCPAN -e 'install Net::Traceroute::PurePerl'
You can also read this README from the CPAN shell:
$ perl -MCPAN -e shell
cpan> readme Net::Traceroute::PurePerl
And you can install the module from the CPAN prompt as well:
cpan> install Net::Traceroute::PurePerl
Manual Installation
Net::Traceroute::PurePerl can also be installed manually.
ftp://ftp-mirror.internap.com/pub/CPAN/authors/id/A/AH/AHOYING/ <ftp://ftp-
mirror.internap.com/pub/CPAN/authors/id/A/AH/AHOYING/> or a similarly named directory at
your favorite CPAN mirror should hold the latest version.
Downloading and unpacking the distribution are left up to the reader.
To build and test it:
perl Makefile.PL
make
make test
The test program, t/01_trace.t, makes an excellent sample program. It was adapted from the
code used to test and develop this module. There may be additional sample programs in the
examples folder.
When you are ready to install the module:
make install
It should now be ready to use.
OVERVIEW
A new Net::Traceroute::PurePerl object must be created with the new method. This will not
perform the traceroute immediately, unlike Net::Traceroute. It will return a "template"
object that can be used to set parameters for several subsequent traceroutes.
Methods are available for accessing information about a given traceroute attempt. There
are also methods that view/modify the options that are passed to the object's constructor.
To trace a route, UDP or ICMP packets are sent with a small TTL (time-to-live) field in an
attempt to get intervening routers to generate ICMP TIME_EXCEEDED messages.
VERSION CHANGES
This version of Net::Traceroute::PurePerl is a complete rewrite of the internal traceroute
code used in the 0.02 release. As such a number of new capabilities have been introduced,
and probably a number of bugs as well.
The public methods have remained unchanged, and this should be a drop in replacement for
the older version.
This version no longer resolves router IPs to host names in the traceroute code. If you
need the IP resolved you have to do it from your code, or use the pretty_print method with
a positive value passed as an argument.
The current version does not correctly detect network unreachable and other nonstandard
ICMP errors. This can lead to problems on networks where these errors are sent instead of
a port unreachable or ttl exceeded packet.
CONSTRUCTOR
$obj = Net::Traceroute::PurePerl->new(
[base_port => $base_port,]
[debug => $debuglvl,]
[max_ttl => $max_ttl,]
[host => $host,]
[queries => $queries,]
[query_timeout => $query_timeout,]
[source_address => $srcaddr,]
[packetlen => $packetlen,]
[concurrent_hops => $concurrent,]
[first_hop => $first_hop,]
[device => $device,]
[protocol => $protocol,]
);
This is the constructor for a new Net::Traceroute object. If given "host", it will NOT
actually perform the traceroute. You MUST call the traceroute method later.
Possible options are:
host - A host to traceroute to. If you don't set this, you get a Traceroute object with
no traceroute data in it. The module always uses IP addresses internally and will attempt
to lookup host names via inet_aton.
base_port - Base port number to use for the UDP queries. Traceroute assumes that nothing
is listening to port "base_port" to "base_port + (nhops * nqueries - 1)" where nhops is
the number of hops required to reach the destination address and nqueries is the number of
queries per hop. Default is what the system traceroute uses (normally 33434)
"Traceroute"'s "-p" option.
debuglvl - A number indicating how verbose debug information should be. Please include
debug=>9 output in bug reports.
max_ttl - Maximum number of hops to try before giving up. Default is what the system
traceroute uses (normally 30). "Traceroute"'s "-m" option.
queries - Number of times to send a query for a given hop. Defaults to whatever the
system traceroute uses (3 for most traceroutes). "Traceroute"'s "-q" option.
query_timeout - How many seconds to wait for a response to each query sent. Uses the
system traceroute's default value of 5 if unspecified. "Traceroute"'s "-w" option.
timeout - unused here
source_address - Select the source address that traceroute will use. "Traceroute"'s "-S"
option.
packetlen - Length of packets to use. Traceroute tries to make the IP packet exactly this
long.
trace_program - unused here
no_fragment - unused at the moment
use_alarm - unused in this version
protocol - Either ICMP or UDP. ICMP uses ICMP echo packets with incrementing sequence
numbers, while UDP uses USP packets with incrementing ports. It defaults to udp.
concurrent_hops - This is the maximum number of outstanding packets sent at one time.
Setting this to a high number may overflow your socket receive buffer and slightly delay
the processing of response packets, making the round trip time reported slightly higher,
however it will significantly decrease the amount of time it takes to run a traceroute.
Defaults to 6.
"Traceroute"'s "-N" option.
first_hop - This is the lowest TTL to use. Setting this will skip the first x routers in
the path, especially useful if they never change. Defaults to 1. "Traceroute"'s "-f"
option.
device - The device to send the packet from. Normally this is determined by the system's
routing table, but it can be overridden. It defaults to undef.
"Traceroute"'s "-I" option.
METHODS
traceroute
Run the traceroute. Will fill in the rest of the object for informational queries.
The traceroute method is a blocking call. It will not return until the max_ttl is
reached or the host is reached. As such, if your program is time dependent the call
should be wrapped in an eval with an ALARM set.
eval {
local $SIG{ALRM} = sub { die "alarm" };
alarm $timeout;
$success = $t->traceroute();
alarm 0;
}
warn "Traceroute timed out\n" if ($@ and $@ eq "alarm");
Returns 1 if the host was reached, or 0 if it wasn't.
Controlling traceroute invocation
Each of these methods return the current value of the option specified by the
corresponding constructor option. They will set the object's instance variable to the
given value if one is provided.
Changing an instance variable will only affect newly performed traceroutes. Setting a
different value on a traceroute object that has already performed a trace has no effect.
See the constructor documentation for information about methods that aren't documented
here.
base_port([PORT])
max_ttl([PORT])
queries([QUERIES])
query_timeout([TIMEOUT])
host([HOST])
source_address([SRC])
packetlen([LEN])
use_alarm([0|1])
protocl([PROTOCOL])
concurrent_hops([CONCURRENT])
first_hop([FIRST_HOP])
device([DEVICE])
Obtaining information about a Trace
These methods return information about a traceroute that has already been performed.
Any of the methods in this section that return a count of something or want an Nth type
count to identify something employ one based counting.
pretty_print
Prints to stdout a traceroute-like text. Tries to mimic traceroute(1)'s output as
close as possible with a few exceptions. First, the columns are easier to read, and
second, a new line is started if the host IP changes instead of printing the new IP
inline. The first column stays the same hop number, only the host changes.
Passing in an argument of 1 will make pretty_print resolve the names of the router
ips, otherwise they are printed as raw ip addresses, like "Traceroute"'s "-n" option.
stat
Returns the status of a given traceroute object. One of TRACEROUTE_OK,
TRACEROUTE_TIMEOUT, or TRACEROUTE_UNKNOWN (each defined as an integer). TRACEROUTE_OK
will only be returned if the host was actually reachable.
found
Returns 1 if the host was found, undef otherwise.
pathmtu
If your traceroute supports MTU discovery, this method will return the MTU in some
circumstances. You must set no_fragment, and must use a packetlen larger than the
path mtu for this to be set.
NOTE: This doesn't work with this version.
hops
Returns the number of hops that it took to reach the host.
hop_queries(HOP)
Returns the number of queries that were sent for a given hop. This should normally be
the same for every query.
hop_query_stat(HOP, QUERY)
Return the status of the given HOP's QUERY. The return status can be one of the
following (each of these is actually an integer constant function defined in
Net::Traceroute's export list):
QUERY can be zero, in which case the first succesful query will be returned.
TRACEROUTE_OK
Reached the host, no problems.
TRACEROUTE_TIMEOUT
This query timed out.
TRACEROUTE_UNKNOWN
Your guess is as good as mine. Shouldn't happen too often.
TRACEROUTE_UNREACH_NET
This hop returned an ICMP Network Unreachable.
TRACEROUTE_UNREACH_HOST
This hop returned an ICMP Host Unreachable.
TRACEROUTE_UNREACH_PROTO
This hop returned an ICMP Protocol unreachable.
TRACEROUTE_UNREACH_NEEDFRAG
Indicates that you can't reach this host without fragmenting your packet further.
Shouldn't happen in regular use.
TRACEROUTE_UNREACH_SRCFAIL
A source routed packet was rejected for some reason. Shouldn't happen.
TRACEROUTE_UNREACH_FILTER_PROHIB
A firewall or similar device has decreed that your traffic is disallowed by
administrative action. Suspect sheer, raving paranoia.
TRACEROUTE_BSDBUG
The destination machine appears to exhibit the 4.[23]BSD time exceeded bug.
hop_query_host(HOP, QUERY)
Return the dotted quad IP address of the host that responded to HOP's QUERY.
QUERY can be zero, in which case the first succesful query will be returned.
hop_query_time(HOP, QUERY)
Return the round trip time associated with the given HOP's query. If your system's
traceroute supports fractional second timing, so will Net::Traceroute.
QUERY can be zero, in which case the first succesful query will be returned.
BUGS and LIMITATIONS
I have not tested the cloning functions of Net::Traceroute::PurePerl. It ought to work,
but if not, BUG me.
This module requires root or administrative privileges to run. It opens a raw socket to
listen for TTL exceeded messages. Take appropriate precautions.
Windows only supports ICMP traceroutes. This may change in a future release, but it is a
real pain since Windows doesn't send ICMP error messages to applications for other
protocols unless the socket is in promiscous mode. :(
The current version does not correctly detect network unreachable and other nonstandard
ICMP errors. This can lead to problems on networks where these errors are sent instead of
a port unreachable or ttl exceeded packet.
The current version does not support Net::Traceroute's clone method. Calling clone will
create an object that is unusable at this point.
TODO
· Implement IPv6 capability.
· Implement TCP traceroute.
· Fix bugs listed above.
SEE ALSO
traceroute(1)
This module's traceroute code was heavily influenced by "Net::Ping".
See the examples folder and the test programs for more examples of this module in action.
AUTHOR
Tom Scanlan <tscanlan@openreach.com> owner Net::Traceroute::PurePerl
Andrew Hoying <ahoying@cpan.org> current co-maintainer of Net::Traceroute::PurePerl. Any
bugs in this release are mine, please send me the bug reports.
Daniel Hagerty <hag@ai.mit.edu> owner of Net::Traceroute and input on this fella
COPYRIGHT
Go right ahead and copy it. 2002 Tom Scanlan. Copyright 2006 by Andrew Hoying. Don't
blame me for damages, just the bugs.
Net::Traceroute::PurePerl is free software; you may redistribute it and or modify it under
the same terms as Perl itself.