C4/SIP/Sip.pm

   1 #
   2 # Sip.pm: General Sip utility functions
   3 #
   4
   5 package Sip;
   6
   7 use strict;
   8 use warnings;
   9 use English;
  10 use Exporter;
  11
  12 use Sys::Syslog qw(syslog);
  13 use POSIX qw(strftime);
  14 use Socket qw(:crlf);
  15
  16 use Sip::Constants qw(SIP_DATETIME);
  17 use Sip::Checksum qw(checksum);
  18
  19 use vars qw($VERSION @ISA @EXPORT_OK %EXPORT_TAGS);
  20
  21 BEGIN {
  22         $VERSION = 1.00;
  23         @ISA = qw(Exporter);
  24
  25         @EXPORT_OK = qw(y_or_n timestamp add_field maybe_add add_count
  26                     denied sipbool boolspace write_msg read_SIP_packet
  27                     $error_detection $protocol_version $field_delimiter
  28                     $last_response);
  29
  30         %EXPORT_TAGS = (
  31                     all => [qw(y_or_n timestamp add_field maybe_add
  32                                add_count denied sipbool boolspace write_msg
  33                                read_SIP_packet
  34                                $error_detection $protocol_version
  35                                $field_delimiter $last_response)]);
  36 }
  37
  38 our $error_detection = 0;
  39 our $protocol_version = 1;
  40 our $field_delimiter = '|';     # Protocol Default
  41
  42 # We need to keep a copy of the last message we sent to the SC,
  43 # in case there's a transmission error and the SC sends us a
  44 # REQUEST_ACS_RESEND.  If we receive a REQUEST_ACS_RESEND before
  45 # we've ever sent anything, then we are to respond with a
  46 # REQUEST_SC_RESEND (p.16)
  47
  48 our $last_response = '';
  49
  50 sub timestamp {
  51     my $time = $_[0] || time();
  52     return strftime(SIP_DATETIME, localtime($time));
  53 }
  54
  55 #
  56 # add_field(field_id, value)
  57 #    return constructed field value
  58 #
  59 sub add_field {
  60     my ($field_id, $value) = @_;
  61     my ($i, $ent);
  62
  63     if (!defined($value)) {
  64         syslog("LOG_DEBUG", "add_field: Undefined value being added to '%s'",
  65                $field_id);
  66                 $value = '';
  67     }
  68
  69     # Replace any occurences of the field delimiter in the
  70     # field value with the HTML character entity
  71     $ent = sprintf("&#%d;", ord($field_delimiter));
  72
  73     while (($i = index($value, $field_delimiter)) != ($[-1)) {
  74                 substr($value, $i, 1) = $ent;
  75     }
  76
  77     return $field_id . $value . $field_delimiter;
  78 }
  79 #
  80 # maybe_add(field_id, value):
  81 #    If value is defined and non-empty, then return the
  82 #    constructed field value, otherwise return the empty string
  83 #
  84 sub maybe_add {
  85     my ($fid, $value) = @_;
  86     return (defined($value) && $value) ? add_field($fid, $value) : '';
  87 }
  88
  89 #
  90 # add_count()  produce fixed four-character count field,
  91 # or a string of four spaces if the count is invalid for some
  92 # reason
  93 #
  94 sub add_count {
  95     my ($label, $count) = @_;
  96
  97     # If the field is unsupported, it will be undef, return blanks
  98     # as per the spec.
  99     if (!defined($count)) {
 100                 return ' ' x 4;
 101     }
 102
 103     $count = sprintf("%04d", $count);
 104     if (length($count) != 4) {
 105                 syslog("LOG_WARNING", "handle_patron_info: %s wrong size: '%s'",
 106                $label, $count);
 107                 $count = ' ' x 4;
 108     }
 109     return $count;
 110 }
 111
 112 #
 113 # denied($bool)
 114 # if $bool is false, return true.  This is because SIP statuses
 115 # are inverted:  we report that something has been denied, not that
 116 # it's permitted.  For example, 'renewal priv. denied' of 'Y' means
 117 # that the user's not permitted to renew.  I assume that the ILS has
 118 # real positive tests.
 119 #
 120 sub denied {
 121     my $bool = shift;
 122     return boolspace(!$bool);
 123 }
 124
 125 sub sipbool {
 126     my $bool = shift;
 127     return $bool ? 'Y' : 'N';
 128 }
 129
 130 #
 131 # boolspace: ' ' is false, 'Y' is true. (don't ask)
 132 #
 133 sub boolspace {
 134     my $bool = shift;
 135     return $bool ? 'Y' : ' ';
 136 }
 137
 138
 139 # Read a packet from $file, using the correct record separator
 140 #
 141 sub read_SIP_packet {
 142     my $record;
 143         my $fh = shift or syslog("LOG_ERR", "read_SIP_packet: no filehandle argument!");
 144         my $len1 = 999;
 145         # local $/ = "\012";    # Internet Record Separator (lax version)
 146         {               # adapted from http://perldoc.perl.org/5.8.8/functions/readline.html
 147                 for (my $tries=1; $tries<=3; $tries++) {
 148                         undef $!;
 149                         $record = readline($fh);
 150                         if (defined($record)) {
 151                                 while(chomp($record)){1;}
 152                                 $len1 = length($record);
 153                                 syslog("LOG_DEBUG", "read_SIP_packet, INPUT MSG: '$record'");
 154                                 $record =~ s/^\s*[^A-z0-9]+//s;
 155                                 $record =~ s/[^A-z0-9]+$//s;
 156                                 $record =~ s/\015?\012//g;
 157                                 $record =~ s/\015?\012//s;
 158                                 $record =~ s/\015*\012*$//s;    # treat as one line to include the extra linebreaks we are trying to remove!
 159                                 while(chomp($record)){1;}
 160                                 if ($record) {
 161                                         last;   # success
 162                                 }
 163                         } else {
 164                                 if ($!) {
 165                                 syslog("LOG_DEBUG", "read_SIP_packet (try #$tries) ERROR: $!");
 166                                         # die "read_SIP_packet ERROR: $!";
 167                                         warn "read_SIP_packet ERROR: $!";
 168                                 }
 169                         }
 170                 }
 171         }
 172         if ($record) {
 173                 my $len2 = length($record);
 174                 syslog("LOG_INFO", "read_SIP_packet, INPUT MSG: '$record'") if $record;
 175                 ($len1 != $len2) and syslog("LOG_DEBUG", "read_SIP_packet, trimmed %s character(s) (after chomps).", $len1-$len2);
 176         } else {
 177                 syslog("LOG_WARNING", "read_SIP_packet input %s, end of input.", (defined($record)? "empty ($record)" : 'undefined'));
 178         }
 179     return $record;
 180 }
 181
 182 #
 183 # write_msg($msg, $file)
 184 #
 185 # Send $msg to the SC.  If error detection is active, then
 186 # add the sequence number (if $seqno is non-zero) and checksum
 187 # to the message, and save the whole thing as $last_response
 188 #
 189 # If $file is set, then it's a file handle: write to it, otherwise
 190 # just write to the default destination.
 191 #
 192
 193 sub write_msg {
 194     my ($self, $msg, $file) = @_;
 195     my $cksum;
 196
 197     if ($error_detection) {
 198                 if (defined($self->{seqno})) {
 199                     $msg .= 'AY' . $self->{seqno};
 200                 }
 201                 $msg .= 'AZ';
 202                 $cksum = checksum($msg);
 203                 $msg .= sprintf('%04.4X', $cksum);
 204     }
 205
 206     if ($file) {
 207                 print $file "$msg$CRLF";
 208                 syslog("LOG_DEBUG", "write_msg outputting to $file");
 209     } else {
 210                 print "$msg$CRLF";
 211     }
 212         syslog("LOG_INFO", "OUTPUT MSG: '$msg'");
 213
 214     $last_response = $msg;
 215 }
 216
 217 1;