#!/bin/sh

# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
#
# SPDX-License-Identifier: MPL-2.0
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0.  If a copy of the MPL was not distributed with this
# file, you can obtain one at https://mozilla.org/MPL/2.0/.
#
# See the COPYRIGHT file distributed with this work for additional
# information regarding copyright ownership.

set -e

. ../conf.sh

# Set known locale for the tests

if locale -a | grep -qE "^C\\.(UTF-8|utf8)"; then
  LC_ALL="C.UTF-8"
elif locale -a | grep -qE "^en_US\\.(UTF-8|utf8)"; then
  LC_ALL="en_US.UTF-8"
fi
export LC_ALL

# This set of tests check the behavior of the IDNA options in "dig".
#
# The tests run "dig" against an authoritative server configured with a minimal
# root zone and nothing else.  As a result, all queries will result in an
# NXDOMAIN.  The server will return the qname sent, which "dig" will display
# according to the options selected.  This returned string is compared with
# the qname originally sent.
#
# In the comments below, the following nomenclature (taken from RFC 5890) is
# used:
#
# A-label: Label comprising ASCII characters that starts xn-- and whose
#          characters after the xn-- are a valid output of the Punycode
#          algorithm.
#
# Fake A-label: An A-label whose characters after the xn-- are not valid
#          Punycode output.
#
# U-label: Unicode (native character) form of a label.
#
# For the purpose of this test script, U-labels do not include labels that
# comprise purely ASCII characters, which are referred to as "ASCII-labels"
# here. Valid ASCII-labels comprise letters, digits and hyphens and do not
# start with a hyphen.
#
# References:
# 1. http://www.unicode.org/reports/tr46/#Deviations
# 2. http://www.unicode.org/reports/tr46/#IDNAComparison

DIGCMD="$DIG -p ${PORT} @10.53.0.1"

# Initialize test count and status return
n=0
status=0

# Function for extracting the qname from the response
#
# This is the first field in the line after the line starting
# ";; QUESTION SECTION:".
#
# The string returned includes the trailing period.

qname() {
  awk 'BEGIN { qs = 0; } \
        /;; QUESTION SECTION:/ { qs = 1; next; } \
        qs == 1 {sub(";", "", $1) ; print $1; exit 0; }' \
    $1
}

# Function for performing a test where "dig" is expected to succeed.
#
#   $1 - Description of the test
#   $2 - Dig command additional options
#   $3 - Name being queried
#   $4 - The name that is expected to be displayed by "dig".  Note that names
#        displayed by "dig" will always have a trailing period, so this
#        parameter should have that period as well.

idna_test() {
  n=$((n + 1))
  description=$1
  if [ "$2" != "" ]; then
    description="${description}: $2"
  fi
  echo_i "$description ($n)"

  ret=0
  {
    $DIGCMD $2 $3 >dig.out.$n 2>&1
    rc=$?
  } || true
  if [ $rc -ne 0 ]; then
    echo_i "failed: dig command returned non-zero status"
    ret=1
  else
    actual=$(qname dig.out.$n)
    if [ "$4" != "$actual" ]; then
      echo_i "failed: expected answer $4, actual result $actual"
      ret=1
    fi
  fi
  status=$((status + ret))
}

# Function for performing a test where "dig" is expected to fail
#
#   $1 - Description of the test
#   $2 - Dig command additional options
#   $3 - Name being queried

idna_fail() {
  n=$((n + 1))
  description=$1
  if [ "$2" != "" ]; then
    description="${description}: $2"
  fi
  echo_i "$description ($n)"

  ret=0
  {
    $DIGCMD $2 $3 >dig.out.$n 2>&1
    rc=$?
  } || true
  if [ $rc -eq 0 ]; then
    echo_i "failed: dig command unexpectedly succeeded"
    ret=1
  fi
  status=$((status + ret))
}

# Function to check that case is preserved for an all-ASCII label.
#
# Without IDNA support, case-preservation is the expected behavior.
#
# With IDNA support... not really.  IDNA maps uppercase ASCII characters to
# their lower-case equivalent.  When IDNA support in "dig" was updated to
# non-transitional IDNA 2008, the switch "+idnin" was added and made the default
# behaviour. This meant that the command "dig LocalhosT" (no command switches)
# sends the qname "localhost", a change in behavior from earlier versions.
#
# This was felt to be confusing to the significant number of users who are
# not interested in IDNA. For this reason, after "dig" passes the input qname
# through the IDNA conversion, is does a case-insensitive comparison with the
# result.  If the two are the same, "dig" can conclude that the qname is
# entirely ASCII and is uses the entered string instead of the converted string
# as the qname.

ascii_case_preservation_test() {
  text="Checking valid ASCII label"
  idna_test "$text" "+noidn" LocalhosT LocalhosT.
  idna_test "$text" "+noidnin +noidnout" LocalhosT LocalhosT.
  idna_test "$text" "+noidnin +idnout" LocalhosT LocalhosT.
  idna_test "$text" "+idnin   +noidnout" LocalhosT LocalhosT.
  idna_test "$text" "+idnin   +idnout" LocalhosT LocalhosT.
  idna_test "$text" "+idn" LocalhosT LocalhosT.
}

# Function to perform the tests if IDNA is enabled.

idna_enabled_test() {
  echo_i "IDNA is enabled, all IDNA tests will be performed"
  # Check that case is preserved on an ASCII label.

  ascii_case_preservation_test

  # Test of a valid U-label
  #
  # +noidnin +noidnout: The label is sent as a unicode octet stream and dig
  #                     will display the string in the \nnn format.
  # +noidnin +idnout:   As for the previous case.
  # +idnin   +noidnout: The label is converted to the xn-- format.  "dig"
  #                     displays the returned xn-- text.
  # +idnin   +idnout:   The label is converted to the xn-- format.  "dig"
  #                     converts the returned xn-- string back to the original
  #                     unicode text.
  #
  # Note that ASCII characters are converted to lower-case.

  text="Checking valid non-ASCII label"
  idna_test "$text" "+noidn" "München" "M\195\188nchen."
  idna_test "$text" "+noidnin +noidnout" "München" "M\195\188nchen."
  idna_test "$text" "+noidnin +idnout" "München" "M\195\188nchen."
  idna_test "$text" "+idnin   +noidnout" "München" "xn--mnchen-3ya."
  idna_test "$text" "+idnin   +idnout" "München" "münchen."
  idna_test "$text" "+idn" "München" "münchen."

  # Tests of transitional processing of a valid U-label
  #
  # IDNA2003 introduced national character sets but, unfortunately, didn't
  # support several characters properly.  One of those was the German
  # character "ß" (the "Eszett" or "sharp s"), which was interpreted as "ss".
  # So the domain “faß.de” domain (for example) was processed as “fass.de”.
  #
  # This was corrected in IDNA2008, although some vendors that adopted this
  # standard chose to keep the existing IDNA2003 translation for this
  # character to prevent problems (e.g. people visiting www.faß.example would,
  # under IDNA2003, go to www.fass.example but under IDNA2008 would end up at
  # www.fa\195\159.example - a different web site).
  #
  # BIND has adopted a (mostly) hard transition, so this test checks that
  # the transitional mapping is not used for characters that are valid in
  # IDNA2008. The tests are essentially the same as for the valid U-label.

  text="Checking that non-transitional IDNA processing is used"
  idna_test "$text" "+noidn" "faß.de" "fa\195\159.de."
  idna_test "$text" "+noidnin +noidnout" "faß.de" "fa\195\159.de."
  idna_test "$text" "+noidnin +idnout" "faß.de" "fa\195\159.de."
  idna_test "$text" "+idnin   +noidnout" "faß.de" "xn--fa-hia.de."
  idna_test "$text" "+idnin   +idnout" "faß.de" "faß.de."
  idna_test "$text" "+idn" "faß.de" "faß.de."

  # Another problem character.  The final character in the first label mapped
  # onto the Greek sigma character ("σ") in IDNA2003.

  text="Second check that non-transitional IDNA processing is used"
  idna_test "$text" "+noidn" "βόλος.com" "\206\178\207\140\206\187\206\191\207\130.com."
  idna_test "$text" "+noidnin +noidnout" "βόλος.com" "\206\178\207\140\206\187\206\191\207\130.com."
  idna_test "$text" "+noidnin +idnout" "βόλος.com" "\206\178\207\140\206\187\206\191\207\130.com."
  idna_test "$text" "+idnin   +noidnout" "βόλος.com" "xn--nxasmm1c.com."
  idna_test "$text" "+idnin   +idnout" "βόλος.com" "βόλος.com."
  idna_test "$text" "+idn" "βόλος.com" "βόλος.com."

  # Tests of a valid A-label (i.e. starting xn--)
  #
  # +noidnout: The string is sent as-is to the server and the returned qname
  #            is displayed in the same form.
  # +idnout:   The string is sent as-is to the server and the returned qname
  #            is displayed as the corresponding U-label.
  #
  # The "+[no]idnin" flag has no effect in these cases.

  text="Checking valid A-label"
  idna_test "$text" "+noidn" "xn--nxasmq6b.com" "xn--nxasmq6b.com."
  idna_test "$text" "+noidnin +noidnout" "xn--nxasmq6b.com" "xn--nxasmq6b.com."
  idna_test "$text" "+noidnin +idnout" "xn--nxasmq6b.com" "βόλοσ.com."
  idna_test "$text" "+idnin +noidnout" "xn--nxasmq6b.com" "xn--nxasmq6b.com."
  idna_test "$text" "+idnin +idnout" "xn--nxasmq6b.com" "βόλοσ.com."
  idna_test "$text" "+idn" "xn--nxasmq6b.com" "βόλοσ.com."

  # Test of valid A-label in locale that cannot display it
  #
  # +noidnout: The string is sent as-is to the server and the returned qname
  #            is displayed in the same form.
  # +idnout:   The string is sent as-is to the server and the returned qname
  #            is displayed as the corresponding A-label.
  #
  # The "+[no]idnout" flag has no effect in these cases.
  saved_LC_ALL="${LC_ALL}"
  LC_ALL="C"
  text="Checking valid A-label in C locale"
  label="xn--nxasmq6b.com"
  if command -v idn2 >/dev/null && ! idn2 -d "$label" >/dev/null 2>/dev/null; then
    idna_test "$text" "+noidn" "$label" "$label."
    idna_test "$text" "+noidnin +noidnout" "$label" "$label."
    idna_test "$text" "+noidnin +idnout" "$label" "$label."
    idna_test "$text" "+idnin +noidnout" "$label" "$label."
    idna_test "$text" "+idnin +idnout" "$label" "$label."
    idna_test "$text" "+noidnin +idnout" "$label" "$label."
    idna_test "$text" "+idn" "$label" "$label."
  fi
  LC_ALL="${saved_LC_ALL}"

  # Tests of invalid A-labels
  #
  # +noidnin: The label is sent as-is to the server and dig will display the
  #           returned fake A-label in the same form.
  # +idnin:   "dig" should report that the label is not correct.
  #
  # +[no]idnout: If the label makes it to the server (via +noidnin), "dig"
  #           should report an error if +idnout is specified.
  #
  # +idn=lax: The label is sent and printed as-is.

  # The minimum length of a punycode A-label is 7 characters.  Check that
  # a shorter label is detected and rejected.

  text="Checking punycode label shorter than minimum valid length"
  idna_test "$text" "+noidn" "xn--xx" "xn--xx."
  idna_test "$text" "+noidnin +noidnout" "xn--xx" "xn--xx."
  idna_test "$text" "+noidnin   +idnout" "xn--xx" "xn--xx."
  idna_test "$text" "+idnin   +noidnout" "xn--xx" "xn--xx."
  idna_test "$text" "+idnin     +idnout" "xn--xx" "xn--xx."
  idna_test "$text" "+idn" "xn--xx" "xn--xx."

  # Fake A-label - the string does not translate to anything.
  # "xn--0000h" decodes to a single "code point" value of U+127252
  # (1,208,914) which is not a legal Unicode code point.
  # (https://www.farsightsecurity.com/blog/txt-record/punycode-20180711/)

  text="Checking fake A-label"
  idna_test "$text" "+noidn" "xn--0000h" "xn--0000h."
  idna_test "$text" "+noidnin +noidnout" "xn--0000h" "xn--0000h."
  idna_test "$text" "+noidnin   +idnout" "xn--0000h" "xn--0000h."
  idna_test "$text" "+idnin   +noidnout" "xn--0000h" "xn--0000h."
  idna_test "$text" "+idnin     +idnout" "xn--0000h" "xn--0000h."
  idna_test "$text" "+idn" "xn--0000h" "xn--0000h."

  # Too long a label. The punycode string is too long (at 64 characters).
  # BIND rejects such labels: with +idnin

  label="xn--xflod18hstflod18hstflod18hstflod18hstflod18hstflod18-1iejjjj"
  text="Checking punycode label longer than maximum valid length"
  idna_fail "$text" "+noidn" "$label"
  idna_fail "$text" "+noidnin +noidnout" "$label"
  idna_fail "$text" "+noidnin   +idnout" "$label"
  idna_fail "$text" "+idnin   +noidnout" "$label"
  idna_fail "$text" "+idnin     +idnout" "$label"
  idna_fail "$text" "+idn" "$label"

  # Tests of a valid unicode string but an invalid U-label (input)
  #
  # Symbols are not valid IDNA2008 names, but are allowed by IDNA2003.
  #
  # +noidnin: "dig" should send unicode octets to the server and display the
  #           returned qname in the same form.
  # +idnin:   "dig" should generate an error.
  #
  # The +[no]idnout options should not have any effect on the test.

  text="Checking invalid input U-label"
  idna_test "$text" "+noidn" "√.com" "\226\136\154.com."
  idna_test "$text" "+noidnin +noidnout" "√.com" "\226\136\154.com."
  idna_test "$text" "+noidnin +idnout" "√.com" "\226\136\154.com."
  idna_test "$text" "+idnin   +noidnout" "√.com" "xn--19g.com."
  idna_test "$text" "+idnin   +idnout" "√.com" "√.com."
  idna_test "$text" "+idn" "√.com" "√.com."

  # Tests of a valid unicode string but an invalid U-label (output)
  #
  # Symbols are not valid IDNA2008 names, but are allowed by IDNA2003.
  #
  # +noidnout: "dig" should send the ACE string to the server and display the
  #            returned qname.
  # +idnout:   "dig" should generate an error.
  #
  # The +[no]idnin options should not have any effect on the test.

  text="Checking invalid output U-label"
  idna_test "$text" "+noidn" "xn--19g" "xn--19g."
  idna_test "$text" "+noidnin +noidnout" "xn--19g" "xn--19g."
  idna_test "$text" "+noidnin +idnout" "xn--19g" "√."
  idna_test "$text" "+idnin   +noidnout" "xn--19g" "xn--19g."
  idna_test "$text" "+idnin   +idnout" "xn--19g" "√."
  idna_test "$text" "+idn" "xn--19g" "√."

  # Test that non-letter characters are preserved in the output.  When
  # UseSTD3ASCIIRules are enabled, it would mangle non-letter characters like
  # `_` (underscore) and `*` (wildcard.

  text="Checking valid non-letter characters"
  idna_test "$text" "+noidn" "*.xn--nxasmq6b.com" "*.xn--nxasmq6b.com."
  idna_test "$text" "+noidnin +noidnout" "*.xn--nxasmq6b.com" "*.xn--nxasmq6b.com."
  idna_test "$text" "+noidnin +idnout" "*.xn--nxasmq6b.com" "*.βόλοσ.com."
  idna_test "$text" "+idnin +noidnout" "*.xn--nxasmq6b.com" "*.xn--nxasmq6b.com."
  idna_test "$text" "+idnin +idnout" "*.xn--nxasmq6b.com" "*.βόλοσ.com."
  idna_test "$text" "+idn" "*.xn--nxasmq6b.com" "*.βόλοσ.com."

  idna_test "$text" "+noidn" "_tcp.xn--nxasmq6b.com" "_tcp.xn--nxasmq6b.com."
  idna_test "$text" "+noidnin +noidnout" "_tcp.xn--nxasmq6b.com" "_tcp.xn--nxasmq6b.com."
  idna_test "$text" "+noidnin +idnout" "_tcp.xn--nxasmq6b.com" "_tcp.βόλοσ.com."
  idna_test "$text" "+idnin +noidnout" "_tcp.xn--nxasmq6b.com" "_tcp.xn--nxasmq6b.com."
  idna_test "$text" "+idnin +idnout" "_tcp.xn--nxasmq6b.com" "_tcp.βόλοσ.com."
  idna_test "$text" "+idn=strict" "_tcp.xn--nxasmq6b.com" "_tcp.βόλοσ.com."
  idna_test "$text" "+idn=lax" "_tcp.xn--nxasmq6b.com" "_tcp.βόλοσ.com."
}

# Function to perform tests if IDNA is not enabled.

idna_disabled_test() {
  echo_i "IDNA is disabled, only case mapping tests will be performed"
  ascii_case_preservation_test
}

# Main test begins here

if $FEATURETEST --with-libidn2; then
  idna_enabled_test
else
  idna_disabled_test
fi

exit $status