#!usr/bin/perl 
use warnings;
use strict;

my $line = '2016-04-17 10:12:27:682011 GMT tcp 115.239.248.245:1751 -> 192.168.0.17:8080 52976f9f34d5c286ecf70cac6fba4506 04159c6111bca4f83d7d606a617acc5d6a58328d3a631adf3795f66a5d6265f4d1ec99977a5ae8cb2f3133c9503e5086a5f2ac92be196bb0c9a9f653f9669495 (312 bytes)';

my ($protocol, $ip, $port, $size)= (split /[\s:()]+/,$line)[6,7,8,-2];

print join ",",($protocol, $ip, $port, $size);
print "\n";

__END__
Prints:
tcp,115.239.248.245,1751,312

To test easily to find the index numbers:
my @x = split /[\s:()]+/,$line;
print join "\n", @x;
use the line number from text editor to see indicies without counting