project_files/frontlib/socket.c
author Wuzzy <Wuzzy2@mail.ru>
Mon, 13 Nov 2017 22:14:45 +0100
changeset 12836 8610462e3d33
parent 10017 de822cd3df3a
permissions -rw-r--r--
Remove 2 unused number tags in Construction Mode GUI These numbers are shown aside the power tag, but the numbers never change. They don't serve any purpose and are just visual clutter and annoying, since they partially overlap. They are probably a leftover from copying code over from other scripts. With this changeset, only the power and turn time are left visible, as it is supposed to.

/*
 * Hedgewars, a free turn based strategy game
 * Copyright (C) 2012 Simeon Maxein <smaxein@googlemail.com>
 *
 * This program 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.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include "socket.h"
#include "util/logging.h"
#include "util/util.h"
#include <stdlib.h>
#include <SDL_net.h>
#include <time.h>

struct _flib_tcpsocket {
    TCPsocket sock;
    SDLNet_SocketSet sockset;
};

struct _flib_acceptor {
    TCPsocket sock;
    uint16_t port;
};

static uint32_t getPeerIp(TCPsocket sock) {
    IPaddress *addr = SDLNet_TCP_GetPeerAddress(sock);
    return SDLNet_Read32(&addr->host);
}

static bool connectionIsLocal(TCPsocket sock) {
    return getPeerIp(sock) == (uint32_t)((127UL<<24)+1); // 127.0.0.1
}

static flib_tcpsocket *createSocket(TCPsocket sdlsock) {
    flib_tcpsocket *result = flib_calloc(1, sizeof(flib_tcpsocket));
    if(result) {
        result->sock = sdlsock;
        result->sockset = SDLNet_AllocSocketSet(1);

        if(!result->sockset) {
            flib_log_e("Can't allocate socket: Out of memory!");
            SDLNet_FreeSocketSet(result->sockset);
            free(result);
            result = NULL;
        } else {
            SDLNet_AddSocket(result->sockset, (SDLNet_GenericSocket)result->sock);
        }
    }
    return result;
}

TCPsocket listen(uint16_t port) {
    IPaddress addr;
    addr.host = INADDR_ANY;
    SDLNet_Write16(port, &addr.port);
    TCPsocket sock = SDLNet_TCP_Open(&addr);
    if(!sock) {
        flib_log_w("Unable to listen on port %u: %s", (unsigned)port, SDLNet_GetError());
    }
    return sock;
}

flib_acceptor *flib_acceptor_create(uint16_t port) {
    flib_acceptor *result = flib_calloc(1, sizeof(flib_acceptor));
    if(result) {
        if(port > 0) {
            result->port = port;
            result->sock = listen(result->port);
        } else {
            /* SDL_net does not seem to have a way to listen on a random unused port
               and find out which port that is, so let's try to find one ourselves. */
            srand(time(NULL));
            for(int i=0; !result->sock && i<1000; i++) {
                // IANA suggests using ports in the range 49152-65535 for things like this
                result->port = 49152+(rand()%(65536-49152));
                result->sock = listen(result->port);
            }
        }
        if(!result->sock) {
            flib_log_e("Failed to create acceptor.");
            free(result);
            result = NULL;
        }
    }
    return result;
}

uint16_t flib_acceptor_listenport(flib_acceptor *acceptor) {
    if(!acceptor) {
        flib_log_e("Call to flib_acceptor_listenport with acceptor==null");
        return 0;
    }
    return acceptor->port;
}

void flib_acceptor_close(flib_acceptor *acceptor) {
    if(acceptor) {
        SDLNet_TCP_Close(acceptor->sock);
        free(acceptor);
    }
}

flib_tcpsocket *flib_socket_accept(flib_acceptor *acceptor, bool localOnly) {
    flib_tcpsocket *result = NULL;
    if(!acceptor) {
        flib_log_e("Call to flib_socket_accept with acceptor==null");
    } else {
        TCPsocket sock = NULL;
        while(!result && (sock = SDLNet_TCP_Accept(acceptor->sock))) {
            if(localOnly && !connectionIsLocal(sock)) {
                flib_log_i("Rejected nonlocal connection attempt from %s", flib_format_ip(getPeerIp(sock)));
            } else {
                result = createSocket(sock);
            }
            if(!result) {
                SDLNet_TCP_Close(sock);
            }
        }
    }
    return result;
}

flib_tcpsocket *flib_socket_connect(const char *host, uint16_t port) {
    flib_tcpsocket *result = NULL;
    if(!host || port==0) {
        flib_log_e("Invalid parameter in flib_socket_connect");
    } else {
        IPaddress ip;
        if(SDLNet_ResolveHost(&ip,host,port)==-1) {
           flib_log_e("SDLNet_ResolveHost: %s\n", SDLNet_GetError());
        } else {
            TCPsocket sock=SDLNet_TCP_Open(&ip);
            if(!sock) {
                flib_log_e("SDLNet_TCP_Open: %s\n", SDLNet_GetError());
            } else {
                result = createSocket(sock);
                if(result) {
                    sock = NULL;
                }
            }
            SDLNet_TCP_Close(sock);
        }
    }
    return result;
}

void flib_socket_close(flib_tcpsocket *sock) {
    if(sock) {
        SDLNet_DelSocket(sock->sockset, (SDLNet_GenericSocket)sock->sock);
        SDLNet_TCP_Close(sock->sock);
        SDLNet_FreeSocketSet(sock->sockset);
        free(sock);
    }
}

int flib_socket_nbrecv(flib_tcpsocket *sock, void *data, int maxlen) {
    if(!sock || (maxlen>0 && !data)) {
        flib_log_e("Call to flib_socket_nbrecv with sock==null or data==null");
        return -1;
    }
    int readySockets = SDLNet_CheckSockets(sock->sockset, 0);
    if(readySockets>0) {
        int size = SDLNet_TCP_Recv(sock->sock, data, maxlen);
        return size>0 ? size : -1;
    } else if(readySockets==0) {
        return 0;
    } else {
        flib_log_e("Error in select system call: %s", SDLNet_GetError());
        return -1;
    }
}

int flib_socket_send(flib_tcpsocket *sock, const void *data, int len) {
    if(!sock || (len>0 && !data)) {
        flib_log_e("Call to flib_socket_send with sock==null or data==null");
        return -1;
    }
    return SDLNet_TCP_Send(sock->sock, data, len);
}