124 lines
2.4 KiB
C++
124 lines
2.4 KiB
C++
// SPDX-License-Identifier: BSD-2-Clause
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// Copyright CM4all GmbH
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// author: Max Kellermann <mk@cm4all.com>
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#include "HostParser.hxx"
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#include "util/CharUtil.hxx"
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#include <cstring>
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static inline bool
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IsValidHostnameChar(char ch) noexcept
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{
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return IsAlphaNumericASCII(ch) ||
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ch == '-' || ch == '.' ||
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ch == '*'; /* for wildcards */
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}
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static inline bool
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IsValidScopeChar(char ch) noexcept
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{
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return IsAlphaNumericASCII(ch) ||
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ch == '-' || ch == '_';
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}
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static const char *
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FindScopeEnd(const char *p) noexcept
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{
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if (*p == '%' && IsValidScopeChar(p[1])) {
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p += 2;
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while (IsValidScopeChar(*p))
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++p;
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}
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return p;
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}
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static inline bool
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IsValidIPv6Char(char ch) noexcept
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{
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return IsDigitASCII(ch) ||
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(ch >= 'a' && ch <= 'f') ||
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(ch >= 'A' && ch <= 'F') ||
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ch == ':';
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}
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static const char *
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FindIPv6End(const char *p) noexcept
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{
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while (IsValidIPv6Char(*p))
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++p;
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/* allow "%scope" after numeric IPv6 address */
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p = FindScopeEnd(p);
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return p;
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}
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static constexpr std::string_view
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SV(const char *begin, const char *end) noexcept
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{
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#if __cplusplus >= 202002 && !defined(__clang__)
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return {begin, end};
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#else
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/* kludge for libc++ which does not yet implement the C++20
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iterator constructor */
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return {begin, std::size_t(end - begin)};
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#endif
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}
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ExtractHostResult
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ExtractHost(const char *src) noexcept
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{
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ExtractHostResult result{{}, src};
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const char *hostname;
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if (IsValidHostnameChar(*src)) {
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const char *colon = nullptr;
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hostname = src++;
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while (IsValidHostnameChar(*src) || *src == ':') {
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if (*src == ':') {
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if (colon != nullptr) {
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/* found a second colon: assume it's an IPv6
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address */
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result.end = FindIPv6End(src + 1);
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result.host = SV(hostname, result.end);
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return result;
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} else
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/* remember the position of the first colon */
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colon = src;
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}
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++src;
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}
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if (colon != nullptr)
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/* hostname ends at colon */
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src = colon;
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result.end = src;
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result.host = SV(hostname, result.end);
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} else if (src[0] == ':' && src[1] == ':') {
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/* IPv6 address beginning with "::" */
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result.end = FindIPv6End(src + 2);
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result.host = SV(src, result.end);
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} else if (src[0] == '[') {
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/* "[hostname]:port" (IPv6?) */
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hostname = ++src;
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const char *end = std::strchr(hostname, ']');
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if (end == nullptr || end == hostname)
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/* failed, return nullptr */
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return result;
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result.host = SV(hostname, end);
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result.end = end + 1;
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} else {
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/* failed, return nullptr */
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}
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return result;
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}
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