initial commit

LICENSE

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+MIT License
+
+Copyright (c) 2023 Erik Scholz
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# NGC custom packet multiplexer
+
+uses a single leading byte in custom packets to determain which callback to call
+
+`ngc_ext.h` is the public c interface
+
+## TODO:
+
+- make c only
+  - merge .hpp into .h
+  - move .cpp to .c
+- public/private packet
+

ngc_ext.cpp

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+#include "./ngc_ext.hpp"
+
+//#include <cstdint>
+#include <new>
+
+using namespace NGC_EXT;
+
+// global scope
+
+NGC_EXT_CTX* NGC_EXT_new(void) {
+	auto* ctx = new NGC_EXT_CTX;
+	// TODO: this is likely not necessary
+	for (auto& it : ctx->callbacks) {
+		it = nullptr;
+	}
+	for (auto& it : ctx->user_data) {
+		it = nullptr;
+	}
+	return ctx;
+}
+
+void NGC_EXT_kill(NGC_EXT_CTX* ngc_ext_ctx) {
+	delete ngc_ext_ctx;
+}
+
+#define _EXT_HAVE(x, error) if ((length - curser) < (x)) { error; }
+void NGC_EXT_handle_group_custom_packet(
+	Tox* tox,
+	NGC_EXT_CTX* ngc_ext_ctx,
+
+	uint32_t group_number,
+	uint32_t peer_number,
+
+	const uint8_t* data,
+	size_t length
+	//void *user_data
+) {
+	size_t curser = 0;
+
+	_EXT_HAVE(1, return)
+
+	PacketType pkg_type = static_cast<PacketType>(*(data + curser));
+	curser++;
+
+	fprintf(stderr, "EX: custom_packet [%s] %lu\n", pkgid2str(pkg_type), length);
+
+	if (pkg_type == INVALID) {
+		fprintf(stderr, "(invalid)\n");
+		return;
+	}
+
+	auto handle_fn = ngc_ext_ctx->callbacks[pkg_type];
+	auto handle_ud = ngc_ext_ctx->user_data[pkg_type]; // can be null
+	if (handle_fn == nullptr) {
+		fprintf(stderr, "EX: !!! no handler for packet\n");
+		return;
+	}
+
+	handle_fn(tox, ngc_ext_ctx, group_number, peer_number, data+curser, length-curser, handle_ud);
+}
+#undef _EXT_HAVE
+
+namespace NGC_EXT {
+
+bool GroupKey::operator<(const GroupKey& rhs) const {
+	for (size_t i = 0; i < data.size(); i++) {
+		if (data[i] < rhs.data[i]) {
+			return true;
+		} else if (data[i] > rhs.data[i]) {
+			return false;
+		}
+	}
+	return false; // equal
+}
+
+bool GroupKey::operator==(const GroupKey& rhs) const {
+	for (size_t i = 0; i < data.size(); i++) {
+		if (data[i] != rhs.data[i]) {
+			return false;
+		}
+	}
+	return true;
+}
+
+bool PeerKey::operator<(const PeerKey& rhs) const {
+	for (size_t i = 0; i < data.size(); i++) {
+		if (data[i] < rhs.data[i]) {
+			return true;
+		} else if (data[i] > rhs.data[i]) {
+			return false;
+		}
+	}
+	return false; // equal
+}
+
+bool PeerKey::operator==(const PeerKey& rhs) const {
+	for (size_t i = 0; i < data.size(); i++) {
+		if (data[i] != rhs.data[i]) {
+			return false;
+		}
+	}
+	return true;
+}
+
+} // NGC_EXT
+

ngc_ext.h

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+#ifndef C_NGC_EXT_H
+#define C_NGC_EXT_H
+
+// this is a c header
+
+#include <tox/tox.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// copy from tox.h:
+#ifndef TOX_DEFINED
+#define TOX_DEFINED
+typedef struct Tox Tox;
+#endif /* TOX_DEFINED */
+
+typedef struct NGC_EXT_CTX NGC_EXT_CTX;
+
+NGC_EXT_CTX* NGC_EXT_new(void);
+void NGC_EXT_kill(NGC_EXT_CTX* ngc_ext_ctx);
+
+void NGC_EXT_handle_group_custom_packet(
+	Tox* tox,
+	NGC_EXT_CTX* ngc_ext_ctx,
+
+	uint32_t group_number,
+	uint32_t peer_number,
+
+	// bool private,
+
+	const uint8_t *data,
+	size_t length
+	//void *user_data
+);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // C_NGC_EXT_H
+

ngc_ext.hpp

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+#pragma once
+
+#include <tox/tox.h>
+
+#include "ngc_ext.h"
+
+#include <array>
+
+// public scope
+
+using handle_group_custom_packet_cb = void(*)(
+	Tox* tox,
+	NGC_EXT_CTX* ngc_ext_ctx, // TODO: useless?
+
+	uint32_t group_number,
+	uint32_t peer_number,
+
+	const uint8_t* data,
+	size_t length,
+	void* user_data
+);
+
+struct NGC_EXT_CTX {
+	std::array<handle_group_custom_packet_cb, 256> callbacks;
+	std::array<void*, 256> user_data;
+};
+
+namespace NGC_EXT {
+
+enum PacketType : uint8_t {
+	// TODO: why?
+	INVALID = 0u,
+
+	//TODO: make it possible to go further back
+	// request last (few) message_ids for a peer
+	// - peer_key bytes (peer key we want to know ids for)
+	// - 1 byte (uint8_t count ids, atleast 1)
+	HS1_REQUEST_LAST_IDS = 1u,
+
+	// respond to a request with 0 or more message ids, sorted by newest first
+	// - peer_key bytes (the msg_ids are from)
+	// - 1 byte (uint8_t count ids, can be 0)
+	// - array [
+	//   - msg_id bytes (the message id)
+	// - ]
+	HS1_RESPONSE_LAST_IDS,
+
+	// request the other side to initiate a FT
+	// - 1 byte (file_kind)
+	// - X bytes (file_kind dependent id, differnt sizes)
+	FT1_REQUEST = 8u,
+
+	// TODO: request result negative, speed up not found
+
+	// tell the other side you want to start a FT
+	// TODO: might use id layer instead. with it, it would look similar to friends_ft
+	// - 1 byte (file_kind)
+	// - 8 bytes (data size, can be 0 if unknown, BUT files have to be atleast 1 byte)
+	// - 1 byte (temporary_file_tf_id, for this peer only, technically just a prefix to distinguish between simultainious fts)
+	// - X bytes (file_kind dependent id, differnt sizes)
+	FT1_INIT,
+
+	// acknowlage init (like an accept)
+	// like tox ft control continue
+	// - 1 byte (transfer_id)
+	FT1_INIT_ACK,
+
+	// TODO: init deny, speed up non acceptance
+
+	// data fragment
+	// - 1 byte (temporary_file_tf_id)
+	// - 2 bytes (sequece id)
+	// - X bytes (the data fragment)
+	// (size is implicit)
+	FT1_DATA,
+
+	// acknowlage data fragments
+	// TODO: last 3 should be sufficient, 5 should be generous
+	// - 1 byte (temporary_file_tf_id)
+	// // this is implicit (pkg size)- 1 byte (number of sequence ids to ack, this kind of depends on window size)
+	// - array [ (of sequece ids)
+	//   - 2 bytes (sequece id)
+	// - ]
+	FT1_DATA_ACK,
+};
+
+// TODO: using alias would be fine
+struct GroupKey {
+	std::array<uint8_t, TOX_GROUP_CHAT_ID_SIZE> data;
+
+	GroupKey(void) = default;
+	GroupKey(const GroupKey& other) : data(other.data) {}
+	GroupKey(GroupKey&&) = delete;
+	GroupKey& operator=(const GroupKey& other) { data = other.data; return *this; }
+	bool operator<(const GroupKey& rhs) const;
+	bool operator==(const GroupKey& rhs) const;
+	size_t size(void) const { return data.size(); }
+};
+
+struct PeerKey {
+	std::array<uint8_t, TOX_GROUP_PEER_PUBLIC_KEY_SIZE> data;
+
+	PeerKey(void) = default;
+	PeerKey(const PeerKey& other) : data(other.data) {}
+	PeerKey(PeerKey&&) = delete;
+	PeerKey& operator=(const PeerKey& other) { data = other.data; return *this; }
+	bool operator<(const PeerKey& rhs) const;
+	bool operator==(const PeerKey& rhs) const;
+	size_t size(void) const { return data.size(); }
+};
+
+[[maybe_unused]] static const char* pkgid2str(PacketType type) {
+#define _EXT_CASE(x) case (x): return #x;
+	switch (type) {
+		_EXT_CASE(INVALID)
+
+		_EXT_CASE(HS1_REQUEST_LAST_IDS)
+		_EXT_CASE(HS1_RESPONSE_LAST_IDS)
+
+		_EXT_CASE(FT1_REQUEST)
+		_EXT_CASE(FT1_INIT)
+		_EXT_CASE(FT1_INIT_ACK)
+		_EXT_CASE(FT1_DATA)
+		_EXT_CASE(FT1_DATA_ACK)
+
+		default: return "<unk>";
+	}
+#undef _EXT_CASE
+}
+
+} // NGC_EXT
+