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tox_extension_messages.c
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tox_extension_messages.c
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#include "tox_extension_messages.h"
#include <toxext/toxext.h>
#include <toxext/toxext_util.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
static uint8_t const uuid[16] = { 0x9e, 0x10, 0x03, 0x16, 0xd2, 0x6f,
0x45, 0x39, 0x8c, 0xdb, 0xae, 0x81,
0x00, 0x42, 0xf8, 0x64 };
enum Messages {
MESSAGE_NEGOTIATE,
MESSAGE_START,
MESSAGE_PART,
MESSAGE_FINISH,
MESSAGE_RECEIVED,
};
struct IncomingMessage {
uint8_t *message;
size_t size;
size_t capacity;
};
struct FriendData {
uint32_t friend_id;
/*
* Incoming message size is only available in the first part of a message.
* If we know the incoming message is too big we set this flag value to
* indicate that all incoming packets should be dropped until the next
* message starts
*/
bool drop_incoming_message;
struct IncomingMessage message;
uint64_t max_sending_size;
};
struct ToxExtensionMessages {
struct ToxExtExtension *extension_handle;
// Ideally we would use a better data structure for this but C doesn't have a ton available
struct FriendData *friend_datas;
size_t friend_datas_size;
uint64_t next_receipt_id;
tox_extension_messages_received_cb cb;
tox_extension_messages_receipt_cb receipt_cb;
tox_extension_messages_negotiate_cb negotiated_cb;
void *userdata;
uint64_t max_receiving_message_size;
};
static struct FriendData *
get_friend_data(struct ToxExtensionMessages *extension, uint32_t friend_id)
{
for (size_t i = 0; i < extension->friend_datas_size; ++i) {
if (extension->friend_datas[i].friend_id == friend_id) {
return &extension->friend_datas[i];
}
}
return NULL;
}
static struct FriendData *
get_or_insert_friend_data(struct ToxExtensionMessages *extension,
uint32_t friend_id)
{
struct FriendData *friend_data = get_friend_data(extension, friend_id);
if (friend_data) {
return friend_data;
}
struct FriendData *new_friend_datas = realloc(
extension->friend_datas,
(extension->friend_datas_size + 1) * sizeof(struct FriendData));
if (!new_friend_datas) {
/* FIXME: We should probably tell the sender that we dropped a message here */
return NULL;
}
extension->friend_datas = new_friend_datas;
extension->friend_datas_size++;
friend_data =
&extension->friend_datas[extension->friend_datas_size - 1];
friend_data->friend_id = friend_id;
friend_data->drop_incoming_message = false;
friend_data->message.message = NULL;
friend_data->message.size = 0;
friend_data->message.capacity = 0;
friend_data->max_sending_size = 0;
return friend_data;
}
static void clear_incoming_message(struct IncomingMessage *incoming_message)
{
free(incoming_message->message);
incoming_message->message = NULL;
incoming_message->size = 0;
incoming_message->capacity = 0;
}
struct MessagesPacket {
enum Messages message_type;
/* On start packets we flag how large the entire buffer will be */
size_t total_message_size;
uint8_t const *message_data;
size_t message_size;
size_t receipt_id;
uint64_t max_sending_message_size;
};
bool parse_messages_packet(uint8_t const *data, size_t size,
struct MessagesPacket *messages_packet)
{
uint8_t const *it = data;
uint8_t const *end = data + size;
if (it + 1 > end) {
return false;
}
messages_packet->message_type = *it;
it += 1;
if (messages_packet->message_type == MESSAGE_RECEIVED) {
messages_packet->receipt_id =
toxext_read_from_buf(uint64_t, it, 8);
return true;
}
else if (messages_packet->message_type == MESSAGE_START) {
if (it + 8 > end) {
return false;
}
messages_packet->total_message_size =
toxext_read_from_buf(uint64_t, it, 8);
it += 8;
}
else if (messages_packet->message_type == MESSAGE_FINISH) {
messages_packet->receipt_id =
toxext_read_from_buf(uint64_t, it, 8);
it += 8;
}
else if (messages_packet->message_type == MESSAGE_NEGOTIATE) {
messages_packet->max_sending_message_size =
toxext_read_from_buf(uint64_t, it, 8);
it += 8;
}
if (it > end) {
return false;
}
messages_packet->message_data = it;
messages_packet->message_size = end - it;
return true;
}
void tox_extension_messages_negotiate_size(
struct ToxExtensionMessages *extension,
struct ToxExtPacketList *response_packet_list)
{
uint8_t data[9];
data[0] = MESSAGE_NEGOTIATE;
toxext_write_to_buf(extension->max_receiving_message_size, data + 1, 8);
toxext_segment_append(response_packet_list, extension->extension_handle,
data, 9);
return;
}
void tox_extension_copy_in_message_data(struct MessagesPacket *parsed_packet,
struct IncomingMessage *incoming_message)
{
if (parsed_packet->message_size + incoming_message->size >
incoming_message->capacity) {
/* FIXME: We should probably tell the sender that we dropped a message here */
clear_incoming_message(incoming_message);
return;
}
memcpy(incoming_message->message + incoming_message->size,
parsed_packet->message_data, parsed_packet->message_size);
incoming_message->size += parsed_packet->message_size;
}
void tox_extension_messages_handle_message_start(
struct ToxExtensionMessages *extension,
struct MessagesPacket *parsed_packet, struct FriendData *friend_data)
{
struct IncomingMessage *incoming_message = &friend_data->message;
if (extension->max_receiving_message_size <
parsed_packet->total_message_size) {
friend_data->drop_incoming_message = true;
return;
}
/*
* realloc here instead of malloc because we may have dropped half a message
* if a user went offline half way through sending
*/
uint8_t *resized_message = realloc(incoming_message->message,
parsed_packet->total_message_size);
if (!resized_message) {
/* FIXME: We should probably tell the sender that we dropped a message here */
clear_incoming_message(incoming_message);
return;
}
incoming_message->message = resized_message;
incoming_message->size = 0;
incoming_message->capacity = parsed_packet->total_message_size;
/*
* If we never got a finish packet we should still do our best to parse the
* next message. This means we need to reset the drop state as well
*/
friend_data->drop_incoming_message = false;
tox_extension_copy_in_message_data(parsed_packet, incoming_message);
}
void tox_extension_messages_handle_message_finish(
struct ToxExtensionMessages *extension, uint32_t friend_id,
struct MessagesPacket *parsed_packet, struct FriendData *friend_data,
struct ToxExtPacketList *response_packet_list)
{
struct IncomingMessage *incoming_message = &friend_data->message;
uint8_t const* message = NULL;
size_t size = 0;
bool end_of_dropped_message = friend_data->drop_incoming_message;
friend_data->drop_incoming_message = false;
/* We can skip the allocate/memcpy here */
if (incoming_message->size == 0) {
message = parsed_packet->message_data;
size = parsed_packet->message_size;
}
else {
tox_extension_copy_in_message_data(parsed_packet, incoming_message);
message = incoming_message->message;
size = incoming_message->size;
}
if (end_of_dropped_message ||
extension->max_receiving_message_size < size) {
/* FIXME: We should probably tell the sender that we dropped a message here */
clear_incoming_message(incoming_message);
return;
}
if (extension->cb) {
extension->cb(friend_id, message, size, extension->userdata);
}
uint8_t data[9];
data[0] = MESSAGE_RECEIVED;
toxext_write_to_buf(parsed_packet->receipt_id, data + 1, 8);
toxext_segment_append(response_packet_list, extension->extension_handle,
data, 9);
clear_incoming_message(incoming_message);
}
void tox_extension_messages_handle_message_part(
struct MessagesPacket *parsed_packet, struct FriendData *friend_data)
{
struct IncomingMessage *incoming_message = &friend_data->message;
if (friend_data->drop_incoming_message) {
/* FIXME: We should probably tell the sender that we dropped a message here */
clear_incoming_message(incoming_message);
return;
}
tox_extension_copy_in_message_data(parsed_packet, incoming_message);
}
static void
tox_extension_messages_recv(struct ToxExtExtension *extension,
uint32_t friend_id, void const *data, size_t size,
void *userdata,
struct ToxExtPacketList *response_packet_list)
{
(void)extension;
struct ToxExtensionMessages *ext_messages = userdata;
struct FriendData *friend_data =
get_friend_data(ext_messages, friend_id);
struct MessagesPacket parsed_packet;
if (!parse_messages_packet(data, size, &parsed_packet)) {
/* FIXME: We should probably tell the sender that they gave us invalid data here */
clear_incoming_message(&friend_data->message);
return;
}
switch (parsed_packet.message_type) {
case MESSAGE_NEGOTIATE:
friend_data->max_sending_size =
parsed_packet.max_sending_message_size;
ext_messages->negotiated_cb(friend_id, true,
friend_data->max_sending_size,
ext_messages->userdata);
return;
case MESSAGE_START:
tox_extension_messages_handle_message_start(
ext_messages, &parsed_packet, friend_data);
return;
case MESSAGE_PART: {
tox_extension_messages_handle_message_part(&parsed_packet,
friend_data);
return;
}
case MESSAGE_FINISH:
tox_extension_messages_handle_message_finish(
ext_messages, friend_id, &parsed_packet, friend_data,
response_packet_list);
return;
case MESSAGE_RECEIVED:
ext_messages->receipt_cb(friend_id, parsed_packet.receipt_id,
ext_messages->userdata);
return;
}
}
static void
tox_extension_messages_neg(struct ToxExtExtension *extension,
uint32_t friend_id, bool compatible, void *userdata,
struct ToxExtPacketList *response_packet_list)
{
(void)extension;
struct ToxExtensionMessages *ext_messages = userdata;
get_or_insert_friend_data(ext_messages, friend_id);
if (!compatible) {
ext_messages->negotiated_cb(friend_id, compatible, 0,
ext_messages->userdata);
} else {
/*
* Do not call the negotiation callback yet. We need to continue with
* our own internal negotiation of max message size. We consider
* ourselves negotiated when our peer has told us what their max packet
* size is
*/
tox_extension_messages_negotiate_size(ext_messages,
response_packet_list);
}
}
struct ToxExtensionMessages *
tox_extension_messages_register(struct ToxExt *toxext,
tox_extension_messages_received_cb cb,
tox_extension_messages_receipt_cb receipt_cb,
tox_extension_messages_negotiate_cb neg_cb,
void *userdata, uint64_t max_receive_size)
{
assert(cb);
struct ToxExtensionMessages *extension =
malloc(sizeof(struct ToxExtensionMessages));
if (!extension) {
return NULL;
}
extension->extension_handle =
toxext_register(toxext, uuid, extension,
tox_extension_messages_recv,
tox_extension_messages_neg);
extension->friend_datas = NULL;
extension->friend_datas_size = 0;
extension->next_receipt_id = 0;
extension->cb = cb;
extension->receipt_cb = receipt_cb;
extension->negotiated_cb = neg_cb;
extension->userdata = userdata;
extension->max_receiving_message_size = max_receive_size;
if (!extension->extension_handle) {
free(extension);
return NULL;
}
return extension;
}
void tox_extension_messages_free(struct ToxExtensionMessages *extension)
{
for (size_t i = 0; i < extension->friend_datas_size; ++i) {
free(extension->friend_datas[i].message.message);
}
free(extension->friend_datas);
free(extension);
}
void tox_extension_messages_negotiate(struct ToxExtensionMessages *extension,
uint32_t friend_id)
{
toxext_negotiate_connection(extension->extension_handle, friend_id);
}
static uint8_t const *
tox_extension_messages_chunk(bool first_chunk, uint8_t const *data, size_t size,
uint64_t receipt_id, uint8_t *extension_data,
size_t *output_size)
{
uint8_t const *ret;
bool last_chunk = size <= TOXEXT_MAX_SEGMENT_SIZE - 9;
if (last_chunk) {
extension_data[0] = MESSAGE_FINISH;
toxext_write_to_buf(receipt_id, extension_data + 1, 8);
size_t advance_size = size;
*output_size = size + 9;
ret = data + advance_size;
memcpy(extension_data + 9, data, advance_size);
} else if (first_chunk) {
extension_data[0] = MESSAGE_START;
toxext_write_to_buf(size, extension_data + 1, 8);
size_t advance_size = TOXEXT_MAX_SEGMENT_SIZE - 9;
memcpy(extension_data + 9, data, advance_size);
*output_size = TOXEXT_MAX_SEGMENT_SIZE;
ret = data + advance_size;
} else {
extension_data[0] = MESSAGE_PART;
size_t advance_size = TOXEXT_MAX_SEGMENT_SIZE - 1;
memcpy(extension_data + 1, data, advance_size);
*output_size = TOXEXT_MAX_SEGMENT_SIZE;
ret = data + advance_size;
}
return ret;
}
uint64_t tox_extension_messages_append(struct ToxExtensionMessages *extension,
struct ToxExtPacketList *packet_list,
uint8_t const *data, size_t size,
uint32_t friend_id,
enum Tox_Extension_Messages_Error *err)
{
enum Tox_Extension_Messages_Error get_max_err;
uint64_t max_sending_size = tox_extension_messages_get_max_sending_size(
extension, friend_id, &get_max_err);
if (get_max_err != TOX_EXTENSION_MESSAGES_SUCCESS ||
size > max_sending_size) {
if (err) {
*err = TOX_EXTENSION_MESSAGES_INVALID_ARG;
}
return -1;
}
uint8_t const *end = data + size;
uint8_t const *next_chunk = data;
bool first_chunk = true;
uint64_t receipt_id = extension->next_receipt_id++;
do {
uint8_t extension_data[TOXEXT_MAX_SEGMENT_SIZE];
size_t size_for_chunk;
next_chunk = tox_extension_messages_chunk(
first_chunk, next_chunk, end - next_chunk, receipt_id,
extension_data, &size_for_chunk);
first_chunk = false;
toxext_segment_append(packet_list, extension->extension_handle,
extension_data, size_for_chunk);
} while (end > next_chunk);
if (err) {
*err = TOX_EXTENSION_MESSAGES_SUCCESS;
}
return receipt_id;
}
uint64_t tox_extension_messages_get_max_receiving_size(
struct ToxExtensionMessages *extension)
{
return extension->max_receiving_message_size;
}
uint64_t tox_extension_messages_get_max_sending_size(
struct ToxExtensionMessages *extension, uint32_t friend_id,
enum Tox_Extension_Messages_Error *err)
{
struct FriendData *friend_datas = get_friend_data(extension, friend_id);
if (!friend_datas) {
*err = TOX_EXTENSION_MESSAGES_INVALID_ARG;
return 0;
}
*err = TOX_EXTENSION_MESSAGES_SUCCESS;
return friend_datas->max_sending_size;
}