ZeroTierOne/node/Dictionary.hpp
2024-09-26 08:52:29 -04:00

507 lines
14 KiB
C++

/*
* Copyright (c)2019 ZeroTier, Inc.
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file in the project's root directory.
*
* Change Date: 2026-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2.0 of the Apache License.
*/
/****/
#ifndef ZT_DICTIONARY_HPP
#define ZT_DICTIONARY_HPP
#include "Address.hpp"
#include "Buffer.hpp"
#include "Constants.hpp"
#include "Utils.hpp"
#include <stdint.h>
namespace ZeroTier {
/**
* A small (in code and data) packed key=value store
*
* This stores data in the form of a compact blob that is sort of human
* readable (depending on whether you put binary data in it) and is backward
* compatible with older versions. Binary data is escaped such that the
* serialized form of a Dictionary is always a valid null-terminated C string.
*
* Keys are restricted: no binary data, no CR/LF, and no equals (=). If a key
* contains these characters it may not be retrievable. This is not checked.
*
* Lookup is via linear search and will be slow with a lot of keys. It's
* designed for small things.
*
* There is code to test and fuzz this in selftest.cpp. Fuzzing a blob of
* pointer tricks like this is important after any modifications.
*
* This is used for network configurations and for saving some things on disk
* in the ZeroTier One service code.
*
* @tparam C Dictionary max capacity in bytes
*/
template <unsigned int C> class Dictionary {
public:
Dictionary()
{
memset(_d, 0, sizeof(_d));
}
Dictionary(const char* s)
{
this->load(s);
}
Dictionary(const char* s, unsigned int len)
{
for (unsigned int i = 0; i < C; ++i) {
if ((s) && (i < len)) {
if (! (_d[i] = *s)) {
s = (const char*)0;
}
else {
++s;
}
}
else {
_d[i] = (char)0;
}
}
_d[C - 1] = (char)0;
}
Dictionary(const Dictionary& d)
{
memcpy(_d, d._d, C);
}
inline Dictionary& operator=(const Dictionary& d)
{
memcpy(_d, d._d, C);
return *this;
}
inline operator bool() const
{
return (_d[0] != 0);
}
/**
* Load a dictionary from a C-string
*
* @param s Dictionary in string form
* @return False if 's' was longer than our capacity
*/
inline bool load(const char* s)
{
for (unsigned int i = 0; i < C; ++i) {
if (s) {
if (! (_d[i] = *s)) {
s = (const char*)0;
}
else {
++s;
}
}
else {
_d[i] = (char)0;
}
}
_d[C - 1] = (char)0;
return (! s);
}
/**
* Delete all entries
*/
inline void clear()
{
memset(_d, 0, sizeof(_d));
}
/**
* @return Size of dictionary in bytes not including terminating NULL
*/
inline unsigned int sizeBytes() const
{
for (unsigned int i = 0; i < C; ++i) {
if (! _d[i]) {
return i;
}
}
return C - 1;
}
/**
* Get an entry
*
* Note that to get binary values, dest[] should be at least one more than
* the maximum size of the value being retrieved. That's because even if
* the data is binary a terminating 0 is still appended to dest[] after it.
*
* If the key is not found, dest[0] is set to 0 to make dest[] an empty
* C string in that case. The dest[] array will *never* be unterminated
* after this call.
*
* Security note: if 'key' is ever directly based on anything that is not
* a hard-code or internally-generated name, it must be checked to ensure
* that the buffer is NULL-terminated since key[] does not take a secondary
* size parameter. In NetworkConfig all keys are hard-coded strings so this
* isn't a problem in the core.
*
* @param key Key to look up
* @param dest Destination buffer
* @param destlen Size of destination buffer
* @return -1 if not found, or actual number of bytes stored in dest[] minus trailing 0
*/
inline int get(const char* key, char* dest, unsigned int destlen) const
{
const char* p = _d;
const char* const eof = p + C;
const char* k;
bool esc;
int j;
if (! destlen) { // sanity check
return -1;
}
while (*p) {
k = key;
while ((*k) && (*p)) {
if (*p != *k) {
break;
}
++k;
if (++p == eof) {
dest[0] = (char)0;
return -1;
}
}
if ((! *k) && (*p == '=')) {
j = 0;
esc = false;
++p;
while ((*p != 0) && (*p != 13) && (*p != 10)) {
if (esc) {
esc = false;
switch (*p) {
case 'r':
dest[j++] = 13;
break;
case 'n':
dest[j++] = 10;
break;
case '0':
dest[j++] = (char)0;
break;
case 'e':
dest[j++] = '=';
break;
default:
dest[j++] = *p;
break;
}
if (j == (int)destlen) {
dest[j - 1] = (char)0;
return j - 1;
}
}
else if (*p == '\\') {
esc = true;
}
else {
dest[j++] = *p;
if (j == (int)destlen) {
dest[j - 1] = (char)0;
return j - 1;
}
}
if (++p == eof) {
dest[0] = (char)0;
return -1;
}
}
dest[j] = (char)0;
return j;
}
else {
while ((*p) && (*p != 13) && (*p != 10)) {
if (++p == eof) {
dest[0] = (char)0;
return -1;
}
}
if (*p) {
if (++p == eof) {
dest[0] = (char)0;
return -1;
}
}
else {
break;
}
}
}
dest[0] = (char)0;
return -1;
}
/**
* Get the contents of a key into a buffer
*
* @param key Key to get
* @param dest Destination buffer
* @return True if key was found (if false, dest will be empty)
* @tparam BC Buffer capacity (usually inferred)
*/
template <unsigned int BC> inline bool get(const char* key, Buffer<BC>& dest) const
{
const int r = this->get(key, const_cast<char*>(reinterpret_cast<const char*>(dest.data())), BC);
if (r >= 0) {
dest.setSize((unsigned int)r);
return true;
}
else {
dest.clear();
return false;
}
}
/**
* Get a boolean value
*
* @param key Key to look up
* @param dfl Default value if not found in dictionary
* @return Boolean value of key or 'dfl' if not found
*/
bool getB(const char* key, bool dfl = false) const
{
char tmp[4];
if (this->get(key, tmp, sizeof(tmp)) >= 0) {
return ((*tmp == '1') || (*tmp == 't') || (*tmp == 'T'));
}
return dfl;
}
/**
* Get an unsigned int64 stored as hex in the dictionary
*
* @param key Key to look up
* @param dfl Default value or 0 if unspecified
* @return Decoded hex UInt value or 'dfl' if not found
*/
inline uint64_t getUI(const char* key, uint64_t dfl = 0) const
{
char tmp[128];
if (this->get(key, tmp, sizeof(tmp)) >= 1) {
return Utils::hexStrToU64(tmp);
}
return dfl;
}
/**
* Get an unsigned int64 stored as hex in the dictionary
*
* @param key Key to look up
* @param dfl Default value or 0 if unspecified
* @return Decoded hex UInt value or 'dfl' if not found
*/
inline int64_t getI(const char* key, int64_t dfl = 0) const
{
char tmp[128];
if (this->get(key, tmp, sizeof(tmp)) >= 1) {
return Utils::hexStrTo64(tmp);
}
return dfl;
}
/**
* Add a new key=value pair
*
* If the key is already present this will append another, but the first
* will always be returned by get(). This is not checked. If you want to
* ensure a key is not present use erase() first.
*
* Use the vlen parameter to add binary values. Nulls will be escaped.
*
* @param key Key -- nulls, CR/LF, and equals (=) are illegal characters
* @param value Value to set
* @param vlen Length of value in bytes or -1 to treat value[] as a C-string and look for terminating 0
* @return True if there was enough room to add this key=value pair
*/
inline bool add(const char* key, const char* value, int vlen = -1)
{
for (unsigned int i = 0; i < C; ++i) {
if (! _d[i]) {
unsigned int j = i;
if (j > 0) {
_d[j++] = (char)10;
if (j == C) {
_d[i] = (char)0;
return false;
}
}
const char* p = key;
while (*p) {
_d[j++] = *(p++);
if (j == C) {
_d[i] = (char)0;
return false;
}
}
_d[j++] = '=';
if (j == C) {
_d[i] = (char)0;
return false;
}
p = value;
int k = 0;
while (((vlen < 0) && (*p)) || (k < vlen)) {
switch (*p) {
case 0:
case 13:
case 10:
case '\\':
case '=':
_d[j++] = '\\';
if (j == C) {
_d[i] = (char)0;
return false;
}
switch (*p) {
case 0:
_d[j++] = '0';
break;
case 13:
_d[j++] = 'r';
break;
case 10:
_d[j++] = 'n';
break;
case '\\':
_d[j++] = '\\';
break;
case '=':
_d[j++] = 'e';
break;
}
if (j == C) {
_d[i] = (char)0;
return false;
}
break;
default:
_d[j++] = *p;
if (j == C) {
_d[i] = (char)0;
return false;
}
break;
}
++p;
++k;
}
_d[j] = (char)0;
return true;
}
}
return false;
}
/**
* Add a boolean as a '1' or a '0'
*/
inline bool add(const char* key, bool value)
{
return this->add(key, (value) ? "1" : "0", 1);
}
/**
* Add a 64-bit integer (unsigned) as a hex value
*/
inline bool add(const char* key, uint64_t value)
{
char tmp[32];
return this->add(key, Utils::hex(value, tmp), -1);
}
/**
* Add a 64-bit integer (unsigned) as a hex value
*/
inline bool add(const char* key, int64_t value)
{
char tmp[32];
if (value >= 0) {
return this->add(key, Utils::hex((uint64_t)value, tmp), -1);
}
else {
tmp[0] = '-';
return this->add(key, Utils::hex((uint64_t)(value * -1), tmp + 1), -1);
}
}
/**
* Add a 64-bit integer (unsigned) as a hex value
*/
inline bool add(const char* key, const Address& a)
{
char tmp[32];
return this->add(key, Utils::hex(a.toInt(), tmp), -1);
}
/**
* Add a binary buffer's contents as a value
*
* @tparam BC Buffer capacity (usually inferred)
*/
template <unsigned int BC> inline bool add(const char* key, const Buffer<BC>& value)
{
return this->add(key, (const char*)value.data(), (int)value.size());
}
/**
* @param key Key to check
* @return True if key is present
*/
inline bool contains(const char* key) const
{
char tmp[2];
return (this->get(key, tmp, 2) >= 0);
}
/**
* @return Value of C template parameter
*/
inline unsigned int capacity() const
{
return C;
}
inline const char* data() const
{
return _d;
}
inline char* unsafeData()
{
return _d;
}
private:
char _d[C];
};
} // namespace ZeroTier
#endif