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/* $Id$ */
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#ifdef ENABLE_NETWORK
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#include "../../stdafx.h"
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#include "../../debug.h"
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#include "../../openttd.h"
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#include "../../variables.h"
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#include "../../table/strings.h"
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#include "../../functions.h"
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#include "os_abstraction.h"
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#include "config.h"
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#include "packet.h"
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#include "../network_data.h"
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#include "tcp.h"
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/**
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* @file tcp.c Basic functions to receive and send TCP packets.
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*/
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/**
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* Functions to help NetworkRecv_Packet/NetworkSend_Packet a bit
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* A socket can make errors. When that happens this handles what to do.
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* For clients: close connection and drop back to main-menu
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* For servers: close connection and that is it
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* @param cs the client to close the connection of
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* @return the new status
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*/
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NetworkRecvStatus CloseConnection(NetworkClientState *cs)
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{
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NetworkCloseClient(cs);
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/* Clients drop back to the main menu */
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if (!_network_server && _networking) {
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_switch_mode = SM_MENU;
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_networking = false;
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_switch_mode_errorstr = STR_NETWORK_ERR_LOSTCONNECTION;
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return NETWORK_RECV_STATUS_CONN_LOST;
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}
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return NETWORK_RECV_STATUS_OKAY;
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}
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/**
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* Whether the client has quit or not (used in packet.c)
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* @param cs the client to check
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* @return true if the client has quit
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*/
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bool HasClientQuit(NetworkClientState *cs)
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{
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return cs->has_quit;
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}
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/**
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* This function puts the packet in the send-queue and it is send as
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* soon as possible. This is the next tick, or maybe one tick later
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* if the OS-network-buffer is full)
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* @param packet the packet to send
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* @param cs the client to send to
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*/
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void NetworkSend_Packet(Packet *packet, NetworkClientState *cs)
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{
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Packet *p;
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assert(packet != NULL);
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packet->pos = 0;
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packet->next = NULL;
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NetworkSend_FillPacketSize(packet);
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/* Locate last packet buffered for the client */
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p = cs->packet_queue;
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if (p == NULL) {
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/* No packets yet */
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cs->packet_queue = packet;
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} else {
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/* Skip to the last packet */
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while (p->next != NULL) p = p->next;
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p->next = packet;
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}
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}
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/**
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* Sends all the buffered packets out for this client. It stops when:
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* 1) all packets are send (queue is empty)
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* 2) the OS reports back that it can not send any more
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* data right now (full network-buffer, it happens ;))
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* 3) sending took too long
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* @param cs the client to send the packets for
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*/
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bool NetworkSend_Packets(NetworkClientState *cs)
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{
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ssize_t res;
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Packet *p;
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/* We can not write to this socket!! */
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if (!cs->writable) return false;
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if (cs->socket == INVALID_SOCKET) return false;
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p = cs->packet_queue;
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while (p != NULL) {
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res = send(cs->socket, p->buffer + p->pos, p->size - p->pos, 0);
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if (res == -1) {
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int err = GET_LAST_ERROR();
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if (err != EWOULDBLOCK) {
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/* Something went wrong.. close client! */
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DEBUG(net, 0, "send failed with error %d", err);
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CloseConnection(cs);
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return false;
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}
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return true;
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}
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if (res == 0) {
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/* Client/server has left us :( */
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CloseConnection(cs);
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return false;
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}
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p->pos += res;
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/* Is this packet sent? */
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if (p->pos == p->size) {
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/* Go to the next packet */
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cs->packet_queue = p->next;
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free(p);
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p = cs->packet_queue;
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} else {
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return true;
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}
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}
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return true;
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}
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/**
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* Receives a packet for the given client
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* @param cs the client to (try to) receive a packet for
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* @param status the variable to store the status into
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* @return the received packet (or NULL when it didn't receive one)
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*/
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Packet *NetworkRecv_Packet(NetworkClientState *cs, NetworkRecvStatus *status)
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{
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ssize_t res;
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Packet *p;
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*status = NETWORK_RECV_STATUS_OKAY;
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if (cs->socket == INVALID_SOCKET) return NULL;
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if (cs->packet_recv == NULL) {
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cs->packet_recv = malloc(sizeof(Packet));
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if (cs->packet_recv == NULL) error("Failed to allocate packet");
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/* Set pos to zero! */
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cs->packet_recv->pos = 0;
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cs->packet_recv->size = 0; // Can be ommited, just for safety reasons
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}
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p = cs->packet_recv;
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/* Read packet size */
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if (p->pos < sizeof(PacketSize)) {
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while (p->pos < sizeof(PacketSize)) {
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/* Read the size of the packet */
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res = recv(cs->socket, p->buffer + p->pos, sizeof(PacketSize) - p->pos, 0);
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if (res == -1) {
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int err = GET_LAST_ERROR();
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if (err != EWOULDBLOCK) {
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/* Something went wrong... (104 is connection reset by peer) */
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if (err != 104) DEBUG(net, 0, "recv failed with error %d", err);
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*status = CloseConnection(cs);
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return NULL;
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}
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/* Connection would block, so stop for now */
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return NULL;
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}
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if (res == 0) {
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/* Client/server has left */
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*status = CloseConnection(cs);
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return NULL;
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}
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p->pos += res;
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}
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NetworkRecv_ReadPacketSize(p);
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if (p->size > SEND_MTU) {
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*status = CloseConnection(cs);
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return NULL;
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}
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}
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/* Read rest of packet */
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while (p->pos < p->size) {
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res = recv(cs->socket, p->buffer + p->pos, p->size - p->pos, 0);
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if (res == -1) {
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int err = GET_LAST_ERROR();
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if (err != EWOULDBLOCK) {
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/* Something went wrong... (104 is connection reset by peer) */
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if (err != 104) DEBUG(net, 0, "recv failed with error %d", err);
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*status = CloseConnection(cs);
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return NULL;
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}
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/* Connection would block */
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return NULL;
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}
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if (res == 0) {
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/* Client/server has left */
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*status = CloseConnection(cs);
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return NULL;
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}
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p->pos += res;
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}
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/* We have a complete packet, return it! */
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p->pos = 2;
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p->next = NULL; // Should not be needed, but who knows...
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/* Prepare for receiving a new packet */
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cs->packet_recv = NULL;
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return p;
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}
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#endif /* ENABLE_NETWORK */
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