From: djfiander <djfiander>
Date: Sat, 26 Aug 2006 18:50:42 +0000 (+0000)
Subject: Go back to using unpack to generate the checksums, except that
X-Git-Url: https://old-git.evergreen-ils.org/?a=commitdiff_plain;h=288e436728d4c70a01b411b8a0e3a1fd6f92d8af;p=SIPServer.git

Go back to using unpack to generate the checksums, except that
I'm using the 'U'TF encoding instead of the 'C'har encoding.
This seems to work, at least in my test environment.
---

diff --git a/Sip/Checksum.pm b/Sip/Checksum.pm
index 07bcd9f..093dfb4 100644
--- a/Sip/Checksum.pm
+++ b/Sip/Checksum.pm
@@ -9,15 +9,8 @@ our @EXPORT_OK = qw(checksum verify_cksum);
 
 sub checksum {
     my $pkt = shift;
-    my $cksum;
-
-    $cksum = 0;
-    foreach my $chr (map(ord, split(//, $pkt))) {
-	$cksum += $chr;
-    }
-    $cksum = (-$cksum) & 0xFFFF;
 
-    return $cksum;
+    return (-unpack('%16U*', $pkt) & 0xFFFF);
 }
 
 sub verify_cksum {
@@ -30,7 +23,7 @@ sub verify_cksum {
     # Convert the checksum back to hex and calculate the sum of the
     # pack without the checksum.
     $cksum = hex(substr($pkt, -4));
-    $shortsum = unpack("%16C*", substr($pkt, 0, -4));
+    $shortsum = unpack("%16U*", substr($pkt, 0, -4));
 
     # The checksum is valid if the hex sum, plus the checksum of the 
     # base packet short when truncated to 16 bits.