sdlbomber/network.c

#include "bomber.h"
#include "announce.h"
#include "game.h"
#include "menu.h"
#include "network.h"
#include "utils.h"

#define MAXMSG 4096

int udpsocket;
const unsigned char gameversion[4]={0xda,0x01,0x00,0x04};

struct netnode netnodes[64];

static int informsize;
static unsigned char regpacket[64];

static struct sockaddr_in myname={0},mastername={0};
static socklen_t senderlength;
static struct sockaddr_in sender={0};

static unsigned char mesg[MAXMSG]="";
uchar needwhole=0;
int mydatacount;
int myslot;
network_type network = NETWORK_NONE;

static unsigned char hist[ACTIONHIST][MAXNETNODES];
int actionput,actioncount;
unsigned char actionblock[ACTIONHIST*MAXNETNODES];

int myaction;
unsigned char actions[MAXNETNODES];

unsigned char latestactions[MAXNETNODES];
long latestcounts[MAXNETNODES];



/* Network I/O, building/checking packets */

#if defined (TEST_LATENCY)
#define NUMQ 512
struct message {
	int time;
	struct sockaddr_in *to;
	int tosize;
	unsigned char msg[512];
	int len;
} message[NUMQ]={0};


outmsgs() {
	int i;

	for(i=0;i<NUMQ;++i) {
		if(message[i].time) {
			--message[i].time;
			if(message[i].time) continue;
			sendto(udpsocket,message[i].msg,message[i].len,0,
				message[i].to,sizeof(struct sockaddr_in));
		}
	}
}
#endif

static int putmsg(struct sockaddr_in *toname,unsigned char *msg,int len) {
	int status;

#if defined (TEST_LATENCY)
	int i;

	for(i=0;i<NUMQ;++i) {
		if(!message[i].time) {
			message[i].time=10;
			message[i].to=toname;
			memcpy(message[i].msg,msg,len);
			message[i].len=len;
			break;
		}
	}
	return 0;
#else
	status=sendto(udpsocket,msg,len,0,
		(struct sockaddr *)toname,sizeof(struct sockaddr_in));
	return status;
#endif

}

static int getmsg(int msec) {
	int size;

	memset(&sender,0,sizeof(sender));
	senderlength=sizeof(sender);
	if(msec) {
		struct timeval timeout;
		fd_set readfds;
		int res;

		memset(&timeout,0,sizeof(timeout));
		timeout.tv_sec=msec/1000;
		timeout.tv_usec=(msec%1000)*1000;
		FD_ZERO(&readfds);
		FD_SET(udpsocket,&readfds);
		res=select(udpsocket+1,&readfds,0,0,&timeout);
		if(res<=0) return -1;
	}
	size=recvfrom(udpsocket,mesg,MAXMSG,0,
		(struct sockaddr *)&sender,&senderlength);
	return size;
}

static int isvalidunique(unsigned char *p) {
	return 0 == memcmp(p, &network_unique, 4);
}

static int isvalidversion(unsigned char *p) {
	return 0 == memcmp(p, gameversion, 4);
}

static unsigned char* writeuint32(unsigned char *p, Uint32 i) {
	p[0]=i>>24L;
	p[1]=i>>16L;
	p[2]=i>>8L;
	p[3]=i;
	return p+4;
}

static Uint32 readuint32(unsigned char *p) {
	return (p[0]<<24L) | (p[1]<<16L) | (p[2]<<8) | p[3];
}

static unsigned char* writeunique(unsigned char *p) {
	memcpy(p, &network_unique, 4);
	return p + 4;
}

static unsigned char* writeversion(unsigned char *p) {
	memcpy(p, &gameversion, 4);
	return p + 4;
}

static int isvalidmsg() {
	int i;
	void *host;
	void *port;

	if (!isvalidunique(mesg+1)) return -1;
	host=&sender.sin_addr.s_addr;
	port=&sender.sin_port;
	for(i=1;i<MAXNETNODES;++i)
		if(netnodes[i].used &&
				!memcmp(&netnodes[i].netname.sin_addr.s_addr,host,4) &&
				!memcmp(&netnodes[i].netname.sin_port,port,2))
			return i;
	return -1;
}

/* Handling game actions */

static void addactions(void) {
	memmove(hist[actionput],actions,MAXNETNODES);
	++actionput;
	if(actionput==ACTIONHIST)
		actionput=0;
	++actioncount;
}

static void buildactions(void) {
	unsigned char *p;
	int i,j;
	p=actionblock;
	i=0;
	while(i<20) {
		if(actioncount-i>0) {
			j=actionput-i-1;
			if(j<0) j+=ACTIONHIST;
			memmove(p,hist[j],MAXNETNODES);
		} else {
			memset(p,0,MAXNETNODES);
		}
		p+=MAXNETNODES;
		++i;
	}
}

static void sendactions(int which) {
	unsigned char msg[512];

	msg[0] = PKT_STEP;
	writeunique(msg+1);
	writeuint32(msg+5, actioncount);
	memcpy(msg+9,actionblock,MAXNETNODES*ACTIONHIST);
	putmsg(&netnodes[which].netname,msg,MAXNETNODES*ACTIONHIST+9);
}

static void sendmine(int frame) {
	unsigned char msg[64];

	msg[0] = PKT_MYDATA;
	writeunique(msg+1);
	writeuint32(msg+5, frame);
	msg[9]=myaction;
	putmsg(&mastername,msg,10);
}

int networktraffic(void) {
	int i;
	int length;
	int whosent;
	unsigned char newactions[MAXNETNODES];
	long now;
	long count;

	switch (network) {
	case NETWORK_NONE:
		return -1;
	case NETWORK_MASTER:
		memcpy(newactions,latestactions,MAXNETNODES);
		newactions[0]=myaction;
		now=gtime();
		for(;;) {
			if(gtime()-now>15) break;
			length=getmsg(5);
			if(length>0 && *mesg!=PKT_MYDATA) fprintf(stderr, "Strange packet %d\n", (int) *mesg);
// check for unexpected old packets...
// for example JOIN on frame 0, respond with BEGIN if player already in game
// respond with uninvite INVITE on JOIN from others
			if(length<10) continue;
			whosent=isvalidmsg();
			if(whosent<=0) continue;
			count=readuint32(mesg+5);
			if(count>latestcounts[whosent]) {
				latestcounts[whosent]=count;
				newactions[whosent]=mesg[9];
			}
		}
		if(myaction==ACT_QUIT) {
			for(i=1;i<MAXNETNODES;++i)
				if(netnodes[i].used)
					newactions[i]=ACT_QUIT;
		}

		memmove(actions,newactions,sizeof(actions));
		addactions();
		buildactions();
		for(i=1;i<MAXNETNODES;++i)
			if(netnodes[i].used)
				sendactions(i);
		for(i=1;i<MAXNETNODES;++i)
			if(netnodes[i].used && actions[i]==ACT_QUIT)
				netnodes[i].used=0;
		return actioncount;
	case NETWORK_SLAVE:
		{
			long latest=-1;
			long lastsent;

			lastsent=now=gtime();
			++mydatacount;
			sendmine(mydatacount);
			for(;;) {
	/*
				if(gtime()-lastsent>=1)
				{
					lastsent=gtime();
					sendmine(mydatacount);
				}
	*/
				if(latest>=0 && gtime()-now>3) break;
				length=getmsg(3);
				if(length==MAXNETNODES*ACTIONHIST+9 &&
						sender.sin_addr.s_addr==mastername.sin_addr.s_addr &&
						sender.sin_port==mastername.sin_port) {
					i=readuint32(mesg+5);
					if(i<latest) continue;
					latest=i;
					memmove(actionblock,mesg+9,MAXNETNODES*ACTIONHIST);
				}
			}
			return latest;
		}
	}
	return -1;
}

/* Handling socket init */

int winsock=0;

void getsocket(void) {
	int status;
	socklen_t slen = sizeof(myname);
#if defined(__WIN32__) || defined(WIN32)
char dummydata[128];

	if(WSAStartup(0x0101,(void *)dummydata)) {
		printf("Windows dumped\n");
		exit(1);
	}
	winsock=1;
#endif

	udpsocket=socket(PF_INET,SOCK_DGRAM,IPPROTO_UDP);
	if(udpsocket==-1) {
		perror("socket()");
		exit(1);
	}
	memset(&myname,0,sizeof(myname));
	myname.sin_family=AF_INET;
	myname.sin_addr.s_addr=htonl(INADDR_ANY);
	myname.sin_port=htons(0);
	status=bind(udpsocket,(struct sockaddr *) &myname,sizeof(myname));
	if(-1 == status) {
		perror("bind()");
		exit(1);
	}
	status = getsockname(udpsocket, (struct sockaddr *) &myname, &slen);
	if(-1 == status) {
		perror("getsockname()");
		exit(1);
	}
}

void freesocket(void) {
#if defined(__WIN32__) || defined(WIN32)
	if(!winsock) return;
	WSACleanup();
#endif
}

/* Join / Host Games */

static void buildinform(unsigned char type) {
	unsigned char *put;
	int i;

	put=mesg;
	*put++=type;
	put = writeunique(put);
	++put; // slot specific for each slave
	for (i = 0; i < MAXNETNODES; ++i) {
		if(!netnodes[i].used) continue;
		*put++=i;
		memmove(put,netnodes[i].name,16);
		put+=16;
	}
	*put++=0xff;
	memcpy(put, configopts, sizeof(configopts));
	put += sizeof(configopts);
	informsize=put-mesg;
}

static void inform1(int which) {
	mesg[5]=which;
	putmsg(&netnodes[which].netname,mesg,informsize);
}

static void inform(unsigned char type) {
	int i;
	buildinform(type);
	for(i=1;i<MAXNETNODES;++i)
		if(netnodes[i].used)
			inform1(i);
}

//returns 0=ignore packet,1=we're rejected,2=INVITE,3=BEGIN
int scaninvite(int msec) {
	int i, size;
	unsigned char *take;
	Uint32 unique = 0;

	size = getmsg(msec);

	if (size < 6) return 0;
	if (*mesg!=PKT_INVITE && *mesg!=PKT_BEGIN) return 0;
	if (sender.sin_family != mastername.sin_family
	 || sender.sin_addr.s_addr != mastername.sin_addr.s_addr
	 || sender.sin_port != mastername.sin_port) return 0;

	myslot=mesg[5];
	if (6 == size || 0xff == mesg[5] || 0xff == mesg[6]) return 1;

	/* update unique */
	memcpy(&unique, mesg+1, 4);
	if (unique != network_unique)
		set_unique(ntohl(unique));

	memset(netnodes,0,sizeof(netnodes));
	size-=6;
	take=mesg+6;
	while(*take!=0xff && size>=17) {
		if((i=*take)<MAXNETNODES) {
			netnodes[i].used=1;
			memmove(netnodes[i].name,take+1,16);
		}
		take+=17;
		size-=17;
	}
	take++; size--; /* read 0xff */

	if(*mesg==PKT_INVITE) {
		return 2;
	} else { /* BEGIN */
		if (size != sizeof(configopts)) {
			fprintf(stderr, "PKT_BEGIN has wrong size: %i != %i\n", size, (int) sizeof(configopts));
			return 1; /* broken packet */
		}
		set_game_options(take);
		return 3;
	}
}

int send_join(struct sockaddr_in *netname, char playername[16]) {
	int res = 0;
	long now;

	set_unique(-1); /* reset unique and random */

	mastername = *netname;
	*regpacket=PKT_JOIN;
	writeversion(regpacket + 1);
	memmove(regpacket+5, playername, 16);
	now=longtime();
	while(longtime()-now<10) {
		putmsg(&mastername,regpacket,1+4+16);
		if (0 == (res=scaninvite(1000))) continue;
		return res;
	}
	return 0;
}

void send_quit() {
	long now;
	int size;

	*regpacket = PKT_QUIT;
	writeunique(regpacket+1);
	now=longtime();
	while(longtime()-now<10) {
		putmsg(&mastername,regpacket,5);
		size=getmsg(1000);
		if(size<6) continue;
		if(mesg[0] != PKT_ACK || mesg[1] != PKT_QUIT) continue;
		if (isvalidunique(mesg+2))
			break;
	}
}

int start_network_game() {
	if(!registergame(playername, myname.sin_port, gameversion)) return 0;
	memset(netnodes,0,sizeof(netnodes));
	netnodes[0].used=1;
	memmove(netnodes[0].name,playername,16);
	myslot=0;
	return 1;
}

int begin_network_game() {
	inform(PKT_BEGIN);
	network = NETWORK_MASTER;
	/* TODO: wait for ack */
	return 1;
}

void send_invites() {
	inform(PKT_INVITE);
}

void cancel_network_game() {
	int i;

	mesg[0] = PKT_INVITE;
	writeunique(mesg+1);
	mesg[5] = 0xff;

	for(i=1;i<MAXNETNODES;++i) {
		if(netnodes[i].used) {
			putmsg(&netnodes[i].netname,mesg,6);
		}
	}
}

int handle_joins() {
	int size;
	int i, j;
	unsigned char temp[64];

	size=getmsg(40);
	switch (*mesg) {
	case PKT_JOIN:
		if (size < 21 || !isvalidversion(mesg+1)) return 0;
		break;
	case PKT_QUIT:
		if (size < 5 || !isvalidunique(mesg+1)) return 0;
		break;
	default:
		return 0;
	}

	/* Find host in list:
	 *   i == MAXETNODES: host not found, otherwise the found host
	 * only if host not found:
	 *   j == -1: no free slot, otherwise first free slot
	 */
	j = -1;
	for (i = 1; i < MAXNETNODES; ++i) {
		if (!netnodes[i].used) {
			if (-1 == j) j = i;
			continue; /* don't compare with unused host */
		}
		if(memcmp(&netnodes[i].netname.sin_addr.s_addr,
			&sender.sin_addr.s_addr,4)) continue;
		if(memcmp(&netnodes[i].netname.sin_port,
			&sender.sin_port,2)) continue;
		/* found host */
		break;
	}

	if(*mesg==PKT_QUIT) {
		if(i < MAXNETNODES) /* if host found, reset entry */
			memset(netnodes+i,0,sizeof(struct netnode));
		/* send always ACK for QUITs */
		*temp=PKT_ACK;
		memmove(temp+1,mesg,5);
		putmsg(&sender,temp,6);
	} else {
		if (i==MAXNETNODES && j==-1) { /* reject */
			*mesg=PKT_INVITE;
			writeunique(mesg+1);
			mesg[5]=0xff;
			putmsg(&sender,mesg,6);
			return 0;
		}

		/* no explicit ack, send invites to all later */
		if(i==MAXNETNODES) i=j;
		memmove(&netnodes[i].netname.sin_addr.s_addr,
			&sender.sin_addr.s_addr,4);
		memmove(&netnodes[i].netname.sin_port,
			&sender.sin_port,2);
		netnodes[i].netname.sin_family=AF_INET;
		netnodes[i].used=1;
		memmove(netnodes[i].name,mesg+5,16);
		netnodes[i].name[15] = '\0';
	}
	return 1;
}