/* =========================================================================== Copyright (C) 1999-2005 Id Software, Inc. Copyright (C) 2000-2009 Darklegion Development This file is part of Tremulous. Tremulous 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; either version 2 of the License, or (at your option) any later version. Tremulous 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. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Tremulous; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA =========================================================================== */ #include "q_shared.h" #include "qcommon.h" /* packet header ------------- 4 outgoing sequence. high bit will be set if this is a fragmented message [2 qport (only for client to server)] [2 fragment start byte] [2 fragment length. if < FRAGMENT_SIZE, this is the last fragment] if the sequence number is -1, the packet should be handled as an out-of-band message instead of as part of a netcon. All fragments will have the same sequence numbers. The qport field is a workaround for bad address translating routers that sometimes remap the client's source port on a packet during gameplay. If the base part of the net address matches and the qport matches, then the channel matches even if the IP port differs. The IP port should be updated to the new value before sending out any replies. */ #define MAX_PACKETLEN 1400 // max size of a network packet #define FRAGMENT_SIZE (MAX_PACKETLEN - 100) #define PACKET_HEADER 10 // two ints and a short #define FRAGMENT_BIT (1<<31) cvar_t *showpackets; cvar_t *showdrop; cvar_t *qport; static char *netsrcString[2] = { "client", "server" }; /* =============== Netchan_Init =============== */ void Netchan_Init( int port ) { port &= 0xffff; showpackets = Cvar_Get ("showpackets", "0", CVAR_TEMP ); showdrop = Cvar_Get ("showdrop", "0", CVAR_TEMP ); qport = Cvar_Get ("net_qport", va("%i", port), CVAR_INIT ); } /* ============== Netchan_Setup called to open a channel to a remote system ============== */ void Netchan_Setup(netsrc_t sock, netchan_t *chan, netadr_t adr, int qport, int challenge) { Com_Memset (chan, 0, sizeof(*chan)); chan->sock = sock; chan->remoteAddress = adr; chan->qport = qport; chan->incomingSequence = 0; chan->outgoingSequence = 1; chan->challenge = challenge; } // TTimo: unused, commenting out to make gcc happy #if 0 /* ============== Netchan_ScramblePacket A probably futile attempt to make proxy hacking somewhat more difficult. ============== */ #define SCRAMBLE_START 6 static void Netchan_ScramblePacket( msg_t *buf ) { unsigned seed; int i, j, c, mask, temp; int seq[MAX_PACKETLEN]; seed = ( LittleLong( *(unsigned *)buf->data ) * 3 ) ^ ( buf->cursize * 123 ); c = buf->cursize; if ( c <= SCRAMBLE_START ) { return; } if ( c > MAX_PACKETLEN ) { Com_Error( ERR_DROP, "MAX_PACKETLEN" ); } // generate a sequence of "random" numbers for (i = 0 ; i < c ; i++) { seed = (119 * seed + 1); seq[i] = seed; } // transpose each character for ( mask = 1 ; mask < c-SCRAMBLE_START ; mask = ( mask << 1 ) + 1 ) { } mask >>= 1; for (i = SCRAMBLE_START ; i < c ; i++) { j = SCRAMBLE_START + ( seq[i] & mask ); temp = buf->data[j]; buf->data[j] = buf->data[i]; buf->data[i] = temp; } // byte xor the data after the header for (i = SCRAMBLE_START ; i < c ; i++) { buf->data[i] ^= seq[i]; } } static void Netchan_UnScramblePacket( msg_t *buf ) { unsigned seed; int i, j, c, mask, temp; int seq[MAX_PACKETLEN]; seed = ( LittleLong( *(unsigned *)buf->data ) * 3 ) ^ ( buf->cursize * 123 ); c = buf->cursize; if ( c <= SCRAMBLE_START ) { return; } if ( c > MAX_PACKETLEN ) { Com_Error( ERR_DROP, "MAX_PACKETLEN" ); } // generate a sequence of "random" numbers for (i = 0 ; i < c ; i++) { seed = (119 * seed + 1); seq[i] = seed; } // byte xor the data after the header for (i = SCRAMBLE_START ; i < c ; i++) { buf->data[i] ^= seq[i]; } // transpose each character in reverse order for ( mask = 1 ; mask < c-SCRAMBLE_START ; mask = ( mask << 1 ) + 1 ) { } mask >>= 1; for (i = c-1 ; i >= SCRAMBLE_START ; i--) { j = SCRAMBLE_START + ( seq[i] & mask ); temp = buf->data[j]; buf->data[j] = buf->data[i]; buf->data[i] = temp; } } #endif /* ================= Netchan_TransmitNextFragment Send one fragment of the current message ================= */ void Netchan_TransmitNextFragment( netchan_t *chan ) { msg_t send; byte send_buf[MAX_PACKETLEN]; int fragmentLength; int outgoingSequence; // write the packet header MSG_InitOOB (&send, send_buf, sizeof(send_buf)); // <-- only do the oob here outgoingSequence = chan->outgoingSequence | FRAGMENT_BIT; MSG_WriteLong(&send, outgoingSequence); // send the qport if we are a client if ( chan->sock == NS_CLIENT ) { MSG_WriteShort( &send, qport->integer ); } MSG_WriteLong(&send, NETCHAN_GENCHECKSUM(chan->challenge, chan->outgoingSequence)); // copy the reliable message to the packet first fragmentLength = FRAGMENT_SIZE; if ( chan->unsentFragmentStart + fragmentLength > chan->unsentLength ) { fragmentLength = chan->unsentLength - chan->unsentFragmentStart; } MSG_WriteShort( &send, chan->unsentFragmentStart ); MSG_WriteShort( &send, fragmentLength ); MSG_WriteData( &send, chan->unsentBuffer + chan->unsentFragmentStart, fragmentLength ); // send the datagram NET_SendPacket( chan->sock, send.cursize, send.data, chan->remoteAddress ); if ( showpackets->integer ) { Com_Printf ("%s send %4i : s=%i fragment=%i,%i\n" , netsrcString[ chan->sock ] , send.cursize , chan->outgoingSequence , chan->unsentFragmentStart, fragmentLength); } chan->unsentFragmentStart += fragmentLength; // this exit condition is a little tricky, because a packet // that is exactly the fragment length still needs to send // a second packet of zero length so that the other side // can tell there aren't more to follow if ( chan->unsentFragmentStart == chan->unsentLength && fragmentLength != FRAGMENT_SIZE ) { chan->outgoingSequence++; chan->unsentFragments = qfalse; } } /* =============== Netchan_Transmit Sends a message to a connection, fragmenting if necessary A 0 length will still generate a packet. ================ */ void Netchan_Transmit( netchan_t *chan, int length, const byte *data ) { msg_t send; byte send_buf[MAX_PACKETLEN]; if ( length > MAX_MSGLEN ) { Com_Error( ERR_DROP, "Netchan_Transmit: length = %i", length ); } chan->unsentFragmentStart = 0; // fragment large reliable messages if ( length >= FRAGMENT_SIZE ) { chan->unsentFragments = qtrue; chan->unsentLength = length; Com_Memcpy( chan->unsentBuffer, data, length ); // only send the first fragment now Netchan_TransmitNextFragment( chan ); return; } // write the packet header MSG_InitOOB (&send, send_buf, sizeof(send_buf)); MSG_WriteLong( &send, chan->outgoingSequence ); // send the qport if we are a client if(chan->sock == NS_CLIENT) MSG_WriteShort(&send, qport->integer); MSG_WriteLong(&send, NETCHAN_GENCHECKSUM(chan->challenge, chan->outgoingSequence)); chan->outgoingSequence++; MSG_WriteData( &send, data, length ); // send the datagram NET_SendPacket( chan->sock, send.cursize, send.data, chan->remoteAddress ); if ( showpackets->integer ) { Com_Printf( "%s send %4i : s=%i ack=%i\n" , netsrcString[ chan->sock ] , send.cursize , chan->outgoingSequence - 1 , chan->incomingSequence ); } } /* ================= Netchan_Process Returns qfalse if the message should not be processed due to being out of order or a fragment. Msg must be large enough to hold MAX_MSGLEN, because if this is the final fragment of a multi-part message, the entire thing will be copied out. ================= */ qboolean Netchan_Process( netchan_t *chan, msg_t *msg ) { int sequence; int qport; int fragmentStart, fragmentLength; int checksum; qboolean fragmented; // XOR unscramble all data in the packet after the header // Netchan_UnScramblePacket( msg ); // get sequence numbers MSG_BeginReadingOOB( msg ); sequence = MSG_ReadLong( msg ); // check for fragment information if ( sequence & FRAGMENT_BIT ) { sequence &= ~FRAGMENT_BIT; fragmented = qtrue; } else { fragmented = qfalse; } // read the qport if we are a server if ( chan->sock == NS_SERVER ) { qport = MSG_ReadShort( msg ); } checksum = MSG_ReadLong(msg); // UDP spoofing protection if(NETCHAN_GENCHECKSUM(chan->challenge, sequence) != checksum) return qfalse; // read the fragment information if ( fragmented ) { fragmentStart = MSG_ReadShort( msg ); fragmentLength = MSG_ReadShort( msg ); } else { fragmentStart = 0; // stop warning message fragmentLength = 0; } if ( showpackets->integer ) { if ( fragmented ) { Com_Printf( "%s recv %4i : s=%i fragment=%i,%i\n" , netsrcString[ chan->sock ] , msg->cursize , sequence , fragmentStart, fragmentLength ); } else { Com_Printf( "%s recv %4i : s=%i\n" , netsrcString[ chan->sock ] , msg->cursize , sequence ); } } // // discard out of order or duplicated packets // if ( sequence <= chan->incomingSequence ) { if ( showdrop->integer || showpackets->integer ) { Com_Printf( "%s:Out of order packet %i at %i\n" , NET_AdrToString( chan->remoteAddress ) , sequence , chan->incomingSequence ); } return qfalse; } // // dropped packets don't keep the message from being used // chan->dropped = sequence - (chan->incomingSequence+1); if ( chan->dropped > 0 ) { if ( showdrop->integer || showpackets->integer ) { Com_Printf( "%s:Dropped %i packets at %i\n" , NET_AdrToString( chan->remoteAddress ) , chan->dropped , sequence ); } } // // if this is the final framgent of a reliable message, // bump incoming_reliable_sequence // if ( fragmented ) { // TTimo // make sure we add the fragments in correct order // either a packet was dropped, or we received this one too soon // we don't reconstruct the fragments. we will wait till this fragment gets to us again // (NOTE: we could probably try to rebuild by out of order chunks if needed) if ( sequence != chan->fragmentSequence ) { chan->fragmentSequence = sequence; chan->fragmentLength = 0; } // if we missed a fragment, dump the message if ( fragmentStart != chan->fragmentLength ) { if ( showdrop->integer || showpackets->integer ) { Com_Printf( "%s:Dropped a message fragment\n" , NET_AdrToString( chan->remoteAddress )); } // we can still keep the part that we have so far, // so we don't need to clear chan->fragmentLength return qfalse; } // copy the fragment to the fragment buffer if ( fragmentLength < 0 || msg->readcount + fragmentLength > msg->cursize || chan->fragmentLength + fragmentLength > sizeof( chan->fragmentBuffer ) ) { if ( showdrop->integer || showpackets->integer ) { Com_Printf ("%s:illegal fragment length\n" , NET_AdrToString (chan->remoteAddress ) ); } return qfalse; } Com_Memcpy( chan->fragmentBuffer + chan->fragmentLength, msg->data + msg->readcount, fragmentLength ); chan->fragmentLength += fragmentLength; // if this wasn't the last fragment, don't process anything if ( fragmentLength == FRAGMENT_SIZE ) { return qfalse; } if ( chan->fragmentLength > msg->maxsize ) { Com_Printf( "%s:fragmentLength %i > msg->maxsize\n" , NET_AdrToString (chan->remoteAddress ), chan->fragmentLength ); return qfalse; } // copy the full message over the partial fragment // make sure the sequence number is still there *(int *)msg->data = LittleLong( sequence ); Com_Memcpy( msg->data + 4, chan->fragmentBuffer, chan->fragmentLength ); msg->cursize = chan->fragmentLength + 4; chan->fragmentLength = 0; msg->readcount = 4; // past the sequence number msg->bit = 32; // past the sequence number // TTimo // clients were not acking fragmented messages chan->incomingSequence = sequence; return qtrue; } // // the message can now be read from the current message pointer // chan->incomingSequence = sequence; return qtrue; } //============================================================================== /* ============================================================================= LOOPBACK BUFFERS FOR LOCAL PLAYER ============================================================================= */ // there needs to be enough loopback messages to hold a complete // gamestate of maximum size #define MAX_LOOPBACK 16 typedef struct { byte data[MAX_PACKETLEN]; int datalen; } loopmsg_t; typedef struct { loopmsg_t msgs[MAX_LOOPBACK]; int get, send; } loopback_t; loopback_t loopbacks[2]; qboolean NET_GetLoopPacket (netsrc_t sock, netadr_t *net_from, msg_t *net_message) { int i; loopback_t *loop; loop = &loopbacks[sock]; if (loop->send - loop->get > MAX_LOOPBACK) loop->get = loop->send - MAX_LOOPBACK; if (loop->get >= loop->send) return qfalse; i = loop->get & (MAX_LOOPBACK-1); loop->get++; Com_Memcpy (net_message->data, loop->msgs[i].data, loop->msgs[i].datalen); net_message->cursize = loop->msgs[i].datalen; Com_Memset (net_from, 0, sizeof(*net_from)); net_from->type = NA_LOOPBACK; return qtrue; } void NET_SendLoopPacket (netsrc_t sock, int length, const void *data, netadr_t to) { int i; loopback_t *loop; loop = &loopbacks[sock^1]; i = loop->send & (MAX_LOOPBACK-1); loop->send++; Com_Memcpy (loop->msgs[i].data, data, length); loop->msgs[i].datalen = length; } //============================================================================= typedef struct packetQueue_s { struct packetQueue_s *next; int length; byte *data; netadr_t to; int release; } packetQueue_t; packetQueue_t *packetQueue = NULL; static void NET_QueuePacket( int length, const void *data, netadr_t to, int offset ) { packetQueue_t *new, *next = packetQueue; if(offset > 999) offset = 999; new = S_Malloc(sizeof(packetQueue_t)); new->data = S_Malloc(length); Com_Memcpy(new->data, data, length); new->length = length; new->to = to; new->release = Sys_Milliseconds() + (int)((float)offset / com_timescale->value); new->next = NULL; if(!packetQueue) { packetQueue = new; return; } while(next) { if(!next->next) { next->next = new; return; } next = next->next; } } void NET_FlushPacketQueue(void) { packetQueue_t *last; int now; while(packetQueue) { now = Sys_Milliseconds(); if(packetQueue->release >= now) break; Sys_SendPacket(packetQueue->length, packetQueue->data, packetQueue->to); last = packetQueue; packetQueue = packetQueue->next; Z_Free(last->data); Z_Free(last); } } void NET_SendPacket( netsrc_t sock, int length, const void *data, netadr_t to ) { // sequenced packets are shown in netchan, so just show oob if ( showpackets->integer && *(int *)data == -1 ) { Com_Printf ("send packet %4i\n", length); } if ( to.type == NA_LOOPBACK ) { NET_SendLoopPacket (sock, length, data, to); return; } if ( to.type == NA_BAD ) { return; } if ( sock == NS_CLIENT && cl_packetdelay->integer > 0 ) { NET_QueuePacket( length, data, to, cl_packetdelay->integer ); } else if ( sock == NS_SERVER && sv_packetdelay->integer > 0 ) { NET_QueuePacket( length, data, to, sv_packetdelay->integer ); } else { Sys_SendPacket( length, data, to ); } } /* =============== NET_OutOfBandPrint Sends a text message in an out-of-band datagram ================ */ void QDECL NET_OutOfBandPrint( netsrc_t sock, netadr_t adr, const char *format, ... ) { va_list argptr; char string[MAX_MSGLEN]; // set the header string[0] = -1; string[1] = -1; string[2] = -1; string[3] = -1; va_start( argptr, format ); Q_vsnprintf( string+4, sizeof(string)-4, format, argptr ); va_end( argptr ); // send the datagram NET_SendPacket( sock, strlen( string ), string, adr ); } /* =============== NET_OutOfBandPrint Sends a data message in an out-of-band datagram (only used for "connect") ================ */ void QDECL NET_OutOfBandData( netsrc_t sock, netadr_t adr, byte *format, int len ) { byte string[MAX_MSGLEN*2]; int i; msg_t mbuf; // set the header string[0] = 0xff; string[1] = 0xff; string[2] = 0xff; string[3] = 0xff; for(i=0;itype = NA_LOOPBACK; // as NA_LOOPBACK doesn't require ports report port was given. return 1; } Q_strncpyz( base, s, sizeof( base ) ); if(*base == '[' || Q_CountChar(base, ':') > 1) { // This is an ipv6 address, handle it specially. search = strchr(base, ']'); if(search) { *search = '\0'; search++; if(*search == ':') port = search + 1; } if(*base == '[') search = base + 1; else search = base; } else { // look for a port number port = strchr( base, ':' ); if ( port ) { *port = '\0'; port++; } search = base; } if(!Sys_StringToAdr(search, a, family)) { a->type = NA_BAD; return 0; } if(port) { a->port = BigShort((short) atoi(port)); return 1; } else { a->port = BigShort(PORT_SERVER); return 2; } }