+
+sub openpgp2ssh {
+ my $instr = shift;
+ my $fpr = shift;
+
+ my $packettag;
+ my $dummy;
+ my $tag;
+
+ while (! eof($instr)) {
+ read($instr, $packettag, 1);
+ $packettag = ord($packettag);
+
+ my $packetlen;
+ if ( ! (0x80 & $packettag)) {
+ die "This is not an OpenPGP packet\n";
+ }
+ if (0x40 & $packettag) {
+ print STDERR "This is a new-style packet header\n";
+ $tag = (0x3f & $packettag);
+ my $nextlen = 0;
+ read($instr, $nextlen, 1);
+ $nextlen = ord($nextlen);
+ if ($nextlen < 192) {
+ $packetlen = $nextlen;
+ } elsif ($nextlen < 224) {
+ my $newoct;
+ read($instr, $newoct, 1);
+ $newoct = ord($newoct);
+ $packetlen = (($nextlen - 192) << 8) + ($newoct) + 192;
+ } elsif ($nextlen == 255) {
+ read($instr, $nextlen, 4);
+ $packetlen = unpack('%L', $nextlen);
+ } else {
+ # packet length is undefined.
+ }
+ } else {
+ my $lentype;
+ print STDERR "This is an old-style packet header\n";
+ $lentype = 0x03 & $packettag;
+ $tag = ( 0x3c & $packettag ) >> 2;
+ if ($lentype == 0) {
+ read($instr, $packetlen, 1) or die "could not read packet length\n";
+ $packetlen = unpack('C', $packetlen);
+ } elsif ($lentype == 1) {
+ read($instr, $packetlen, 2) or die "could not read packet length\n";
+ $packetlen = unpack('n', $packetlen);
+ } elsif ($lentype == 2) {
+ read($instr, $packetlen, 4) or die "could not read packet length\n";
+ $packetlen = unpack('N', $packetlen);
+ } else {
+ # packet length is undefined.
+ }
+ }
+
+ if (! defined($packetlen)) {
+ die "Undefined packet lengths are not supported.\n";
+ }
+ printf(STDERR "Packet is %d long\n", $packetlen);
+
+ if ($tag == $packet_types->{pubkey} ||
+ $tag == $packet_types->{pub_subkey} ||
+ $tag == $packet_types->{seckey} ||
+ $tag == $packet_types->{sec_subkey}) {
+ printf(STDERR "Packet type %d\n", $tag);
+ read($instr, $dummy, $packetlen) or die "Could not seek!\n";
+ } else {
+ printf(STDERR "We do not care about this packet.\n");
+ read($instr, $dummy, $packetlen) or die "Could not seek!\n";
+ }
+ }
+
+ print $tag;