mirror of https://github.com/OpenTTD/OpenTTD.git
Codechange: move logic whether there is enough space in a packet to write data into the Packet
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c545cc9d70
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@ -68,6 +68,16 @@ void Packet::PrepareToSend()
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this->pos = 0; // We start reading from here
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}
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/**
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* Is it safe to write to the packet, i.e. didn't we run over the buffer?
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* @param bytes_to_write The amount of bytes we want to try to write.
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* @return True iff the given amount of bytes can be written to the packet.
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*/
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bool Packet::CanWriteToPacket(size_t bytes_to_write)
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{
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return this->size + bytes_to_write < SEND_MTU;
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}
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/*
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* The next couple of functions make sure we can send
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* uint8, uint16, uint32 and uint64 endian-safe
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@ -95,7 +105,7 @@ void Packet::Send_bool(bool data)
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*/
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void Packet::Send_uint8(uint8 data)
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{
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assert(this->size < SEND_MTU - sizeof(data));
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assert(this->CanWriteToPacket(sizeof(data)));
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this->buffer[this->size++] = data;
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}
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@ -105,7 +115,7 @@ void Packet::Send_uint8(uint8 data)
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*/
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void Packet::Send_uint16(uint16 data)
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{
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assert(this->size < SEND_MTU - sizeof(data));
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assert(this->CanWriteToPacket(sizeof(data)));
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this->buffer[this->size++] = GB(data, 0, 8);
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this->buffer[this->size++] = GB(data, 8, 8);
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}
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@ -116,7 +126,7 @@ void Packet::Send_uint16(uint16 data)
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*/
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void Packet::Send_uint32(uint32 data)
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{
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assert(this->size < SEND_MTU - sizeof(data));
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assert(this->CanWriteToPacket(sizeof(data)));
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this->buffer[this->size++] = GB(data, 0, 8);
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this->buffer[this->size++] = GB(data, 8, 8);
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this->buffer[this->size++] = GB(data, 16, 8);
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@ -129,7 +139,7 @@ void Packet::Send_uint32(uint32 data)
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*/
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void Packet::Send_uint64(uint64 data)
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{
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assert(this->size < SEND_MTU - sizeof(data));
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assert(this->CanWriteToPacket(sizeof(data)));
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this->buffer[this->size++] = GB(data, 0, 8);
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this->buffer[this->size++] = GB(data, 8, 8);
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this->buffer[this->size++] = GB(data, 16, 8);
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@ -148,8 +158,8 @@ void Packet::Send_uint64(uint64 data)
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void Packet::Send_string(const char *data)
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{
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assert(data != nullptr);
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/* The <= *is* valid due to the fact that we are comparing sizes and not the index. */
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assert(this->size + strlen(data) + 1 <= SEND_MTU);
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/* Length of the string + 1 for the '\0' termination. */
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assert(this->CanWriteToPacket(strlen(data) + 1));
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while ((this->buffer[this->size++] = *data++) != '\0') {}
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}
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@ -162,18 +172,21 @@ void Packet::Send_string(const char *data)
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/**
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* Is it safe to read from the packet, i.e. didn't we run over the buffer ?
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* @param bytes_to_read The amount of bytes we want to try to read.
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* Is it safe to read from the packet, i.e. didn't we run over the buffer?
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* In case \c close_connection is true, the connection will be closed when one would
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* overrun the buffer. When it is false, the connection remains untouched.
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* @param bytes_to_read The amount of bytes we want to try to read.
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* @param close_connection Whether to close the connection if one cannot read that amount.
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* @return True if that is safe, otherwise false.
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*/
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bool Packet::CanReadFromPacket(uint bytes_to_read)
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bool Packet::CanReadFromPacket(size_t bytes_to_read, bool close_connection)
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{
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/* Don't allow reading from a quit client/client who send bad data */
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if (this->cs->HasClientQuit()) return false;
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/* Check if variable is within packet-size */
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if (this->pos + bytes_to_read > this->size) {
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this->cs->NetworkSocketHandler::CloseConnection();
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if (close_connection) this->cs->NetworkSocketHandler::CloseConnection();
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return false;
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}
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@ -235,7 +248,7 @@ uint8 Packet::Recv_uint8()
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{
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uint8 n;
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if (!this->CanReadFromPacket(sizeof(n))) return 0;
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if (!this->CanReadFromPacket(sizeof(n), true)) return 0;
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n = this->buffer[this->pos++];
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return n;
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@ -249,7 +262,7 @@ uint16 Packet::Recv_uint16()
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{
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uint16 n;
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if (!this->CanReadFromPacket(sizeof(n))) return 0;
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if (!this->CanReadFromPacket(sizeof(n), true)) return 0;
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n = (uint16)this->buffer[this->pos++];
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n += (uint16)this->buffer[this->pos++] << 8;
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@ -264,7 +277,7 @@ uint32 Packet::Recv_uint32()
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{
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uint32 n;
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if (!this->CanReadFromPacket(sizeof(n))) return 0;
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if (!this->CanReadFromPacket(sizeof(n), true)) return 0;
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n = (uint32)this->buffer[this->pos++];
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n += (uint32)this->buffer[this->pos++] << 8;
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@ -281,7 +294,7 @@ uint64 Packet::Recv_uint64()
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{
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uint64 n;
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if (!this->CanReadFromPacket(sizeof(n))) return 0;
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if (!this->CanReadFromPacket(sizeof(n), true)) return 0;
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n = (uint64)this->buffer[this->pos++];
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n += (uint64)this->buffer[this->pos++] << 8;
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@ -63,6 +63,7 @@ public:
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/* Sending/writing of packets */
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void PrepareToSend();
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bool CanWriteToPacket(size_t bytes_to_write);
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void Send_bool (bool data);
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void Send_uint8 (uint8 data);
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void Send_uint16(uint16 data);
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@ -75,7 +76,7 @@ public:
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bool ParsePacketSize();
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void PrepareToRead();
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bool CanReadFromPacket (uint bytes_to_read);
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bool CanReadFromPacket(size_t bytes_to_read, bool close_connection = false);
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bool Recv_bool ();
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uint8 Recv_uint8 ();
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uint16 Recv_uint16();
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@ -613,7 +613,7 @@ NetworkRecvStatus ServerNetworkAdminSocketHandler::SendCmdNames()
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/* Should SEND_MTU be exceeded, start a new packet
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* (magic 5: 1 bool "more data" and one uint16 "command id", one
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* byte for string '\0' termination and 1 bool "no more data" */
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if (p->size + strlen(cmdname) + 5 >= SEND_MTU) {
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if (p->CanWriteToPacket(strlen(cmdname) + 5)) {
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p->Send_bool(false);
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this->SendPacket(p);
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@ -933,7 +933,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_FRAME(Packet *p
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}
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#endif
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/* Receive the token. */
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if (p->pos != p->size) this->token = p->Recv_uint8();
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if (p->CanReadFromPacket(sizeof(uint8))) this->token = p->Recv_uint8();
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DEBUG(net, 5, "Received FRAME %d", _frame_counter_server);
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@ -220,23 +220,23 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_DETAIL_INFO(Packet *p, Networ
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static const uint MIN_CI_SIZE = 54;
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uint max_cname_length = NETWORK_COMPANY_NAME_LENGTH;
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if (Company::GetNumItems() * (MIN_CI_SIZE + NETWORK_COMPANY_NAME_LENGTH) >= (uint)SEND_MTU - packet.size) {
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if (!packet.CanWriteToPacket(Company::GetNumItems() * (MIN_CI_SIZE + NETWORK_COMPANY_NAME_LENGTH))) {
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/* Assume we can at least put the company information in the packets. */
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assert(Company::GetNumItems() * MIN_CI_SIZE < (uint)SEND_MTU - packet.size);
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assert(packet.CanWriteToPacket(Company::GetNumItems() * MIN_CI_SIZE));
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/* At this moment the company names might not fit in the
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* packet. Check whether that is really the case. */
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for (;;) {
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int free = SEND_MTU - packet.size;
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size_t required = 0;
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for (const Company *company : Company::Iterate()) {
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char company_name[NETWORK_COMPANY_NAME_LENGTH];
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SetDParam(0, company->index);
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GetString(company_name, STR_COMPANY_NAME, company_name + max_cname_length - 1);
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free -= MIN_CI_SIZE;
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free -= (int)strlen(company_name);
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required += MIN_CI_SIZE;
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required += strlen(company_name);
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}
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if (free >= 0) break;
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if (packet.CanWriteToPacket(required)) break;
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/* Try again, with slightly shorter strings. */
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assert(max_cname_length > 0);
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