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