packet.cpp

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00001 /* $Id$ */
00002 
00003 /*
00004  * This file is part of OpenTTD.
00005  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
00006  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
00008  */
00009 
00014 #ifdef ENABLE_NETWORK
00015 
00016 #include "../../stdafx.h"
00017 #include "../../string_func.h"
00018 
00019 #include "packet.h"
00020 
00025 Packet::Packet(NetworkSocketHandler *cs)
00026 {
00027   assert(cs != NULL);
00028 
00029   this->cs     = cs;
00030   this->next   = NULL;
00031   this->pos    = 0; // We start reading from here
00032   this->size   = 0;
00033   this->buffer = MallocT<byte>(SEND_MTU);
00034 }
00035 
00040 Packet::Packet(PacketType type)
00041 {
00042   this->cs                   = NULL;
00043   this->next                 = NULL;
00044 
00045   /* Skip the size so we can write that in before sending the packet */
00046   this->pos                  = 0;
00047   this->size                 = sizeof(PacketSize);
00048   this->buffer               = MallocT<byte>(SEND_MTU);
00049   this->buffer[this->size++] = type;
00050 }
00051 
00055 Packet::~Packet()
00056 {
00057   free(this->buffer);
00058 }
00059 
00063 void Packet::PrepareToSend()
00064 {
00065   assert(this->cs == NULL && this->next == NULL);
00066 
00067   this->buffer[0] = GB(this->size, 0, 8);
00068   this->buffer[1] = GB(this->size, 8, 8);
00069 
00070   this->pos  = 0; // We start reading from here
00071 }
00072 
00073 /*
00074  * The next couple of functions make sure we can send
00075  *  uint8, uint16, uint32 and uint64 endian-safe
00076  *  over the network. The least significant bytes are
00077  *  sent first.
00078  *
00079  *  So 0x01234567 would be sent as 67 45 23 01.
00080  *
00081  * A bool is sent as a uint8 where zero means false
00082  *  and non-zero means true.
00083  */
00084 
00089 void Packet::Send_bool(bool data)
00090 {
00091   this->Send_uint8(data ? 1 : 0);
00092 }
00093 
00098 void Packet::Send_uint8(uint8 data)
00099 {
00100   assert(this->size < SEND_MTU - sizeof(data));
00101   this->buffer[this->size++] = data;
00102 }
00103 
00108 void Packet::Send_uint16(uint16 data)
00109 {
00110   assert(this->size < SEND_MTU - sizeof(data));
00111   this->buffer[this->size++] = GB(data, 0, 8);
00112   this->buffer[this->size++] = GB(data, 8, 8);
00113 }
00114 
00119 void Packet::Send_uint32(uint32 data)
00120 {
00121   assert(this->size < SEND_MTU - sizeof(data));
00122   this->buffer[this->size++] = GB(data,  0, 8);
00123   this->buffer[this->size++] = GB(data,  8, 8);
00124   this->buffer[this->size++] = GB(data, 16, 8);
00125   this->buffer[this->size++] = GB(data, 24, 8);
00126 }
00127 
00132 void Packet::Send_uint64(uint64 data)
00133 {
00134   assert(this->size < SEND_MTU - sizeof(data));
00135   this->buffer[this->size++] = GB(data,  0, 8);
00136   this->buffer[this->size++] = GB(data,  8, 8);
00137   this->buffer[this->size++] = GB(data, 16, 8);
00138   this->buffer[this->size++] = GB(data, 24, 8);
00139   this->buffer[this->size++] = GB(data, 32, 8);
00140   this->buffer[this->size++] = GB(data, 40, 8);
00141   this->buffer[this->size++] = GB(data, 48, 8);
00142   this->buffer[this->size++] = GB(data, 56, 8);
00143 }
00144 
00150 void Packet::Send_string(const char *data)
00151 {
00152   assert(data != NULL);
00153   /* The <= *is* valid due to the fact that we are comparing sizes and not the index. */
00154   assert(this->size + strlen(data) + 1 <= SEND_MTU);
00155   while ((this->buffer[this->size++] = *data++) != '\0') {}
00156 }
00157 
00158 
00159 /*
00160  * Receiving commands
00161  * Again, the next couple of functions are endian-safe
00162  *  see the comment before Send_bool for more info.
00163  */
00164 
00165 
00171 bool Packet::CanReadFromPacket(uint bytes_to_read)
00172 {
00173   /* Don't allow reading from a quit client/client who send bad data */
00174   if (this->cs->HasClientQuit()) return false;
00175 
00176   /* Check if variable is within packet-size */
00177   if (this->pos + bytes_to_read > this->size) {
00178     this->cs->NetworkSocketHandler::CloseConnection();
00179     return false;
00180   }
00181 
00182   return true;
00183 }
00184 
00188 void Packet::ReadRawPacketSize()
00189 {
00190   assert(this->cs != NULL && this->next == NULL);
00191   this->size  = (PacketSize)this->buffer[0];
00192   this->size += (PacketSize)this->buffer[1] << 8;
00193 }
00194 
00198 void Packet::PrepareToRead()
00199 {
00200   this->ReadRawPacketSize();
00201 
00202   /* Put the position on the right place */
00203   this->pos = sizeof(PacketSize);
00204 }
00205 
00210 bool Packet::Recv_bool()
00211 {
00212   return this->Recv_uint8() != 0;
00213 }
00214 
00219 uint8 Packet::Recv_uint8()
00220 {
00221   uint8 n;
00222 
00223   if (!this->CanReadFromPacket(sizeof(n))) return 0;
00224 
00225   n = this->buffer[this->pos++];
00226   return n;
00227 }
00228 
00233 uint16 Packet::Recv_uint16()
00234 {
00235   uint16 n;
00236 
00237   if (!this->CanReadFromPacket(sizeof(n))) return 0;
00238 
00239   n  = (uint16)this->buffer[this->pos++];
00240   n += (uint16)this->buffer[this->pos++] << 8;
00241   return n;
00242 }
00243 
00248 uint32 Packet::Recv_uint32()
00249 {
00250   uint32 n;
00251 
00252   if (!this->CanReadFromPacket(sizeof(n))) return 0;
00253 
00254   n  = (uint32)this->buffer[this->pos++];
00255   n += (uint32)this->buffer[this->pos++] << 8;
00256   n += (uint32)this->buffer[this->pos++] << 16;
00257   n += (uint32)this->buffer[this->pos++] << 24;
00258   return n;
00259 }
00260 
00265 uint64 Packet::Recv_uint64()
00266 {
00267   uint64 n;
00268 
00269   if (!this->CanReadFromPacket(sizeof(n))) return 0;
00270 
00271   n  = (uint64)this->buffer[this->pos++];
00272   n += (uint64)this->buffer[this->pos++] << 8;
00273   n += (uint64)this->buffer[this->pos++] << 16;
00274   n += (uint64)this->buffer[this->pos++] << 24;
00275   n += (uint64)this->buffer[this->pos++] << 32;
00276   n += (uint64)this->buffer[this->pos++] << 40;
00277   n += (uint64)this->buffer[this->pos++] << 48;
00278   n += (uint64)this->buffer[this->pos++] << 56;
00279   return n;
00280 }
00281 
00288 void Packet::Recv_string(char *buffer, size_t size, bool allow_newlines)
00289 {
00290   PacketSize pos;
00291   char *bufp = buffer;
00292   const char *last = buffer + size - 1;
00293 
00294   /* Don't allow reading from a closed socket */
00295   if (cs->HasClientQuit()) return;
00296 
00297   pos = this->pos;
00298   while (--size > 0 && pos < this->size && (*buffer++ = this->buffer[pos++]) != '\0') {}
00299 
00300   if (size == 0 || pos == this->size) {
00301     *buffer = '\0';
00302     /* If size was sooner to zero then the string in the stream
00303      *  skip till the \0, so than packet can be read out correctly for the rest */
00304     while (pos < this->size && this->buffer[pos] != '\0') pos++;
00305     pos++;
00306   }
00307   this->pos = pos;
00308 
00309   str_validate(bufp, last, allow_newlines);
00310 }
00311 
00312 #endif /* ENABLE_NETWORK */

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