shithub: musw

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implemented a keep alive mechanism.

also changed the newframe fn to take a Udphdr* instead of a Frame*.
the verifyframe fn now returns 1 if correct 0 otherwise.

--- a/dat.h

+++ b/dat.h

@@ -47,7 +47,8 @@

 enum {

 	ProtocolID	= 0x5753554d,	/* MUSW */

 	Framehdrsize	= 4+1+4+4+2+MD5dlen,

-	MTU		= 1024

+	MTU		= 1024,

+	ConnTimeout	= 10000		/* in ms */

 };

 typedef struct VModel VModel;

@@ -163,12 +164,14 @@

 	NCState state;

 	u32int lastseq;

 	u32int lastack;

+	ulong lastrecvts;	/* last time a packet was received (in ms) */

+	ulong lastnudgets;	/* last time a nudge was sent (in ms) */

 };

 struct Player

 {

 	char *name;

-	NetConn conn;

+	NetConn *conn;

 	ulong okdown, kdown;

 };

--- a/fns.h

+++ b/fns.h

@@ -52,7 +52,7 @@

 ulong dhgenkey(ulong, ulong, ulong);

 NetConn *newnetconn(NCState, Udphdr*);

 void delnetconn(NetConn*);

-Frame *newframe(Frame*, u8int, u32int, u32int, u16int, uchar*);

+Frame *newframe(Udphdr*, u8int, u32int, u32int, u16int, uchar*);

 void signframe(Frame*, ulong);

 int verifyframe(Frame*, ulong);

 void delframe(Frame*);

--- a/musw.c

+++ b/musw.c

@@ -268,7 +268,7 @@

 			case NShi:

 				unpack(frame->data, frame->len, "kk", &netconn.dh.p, &netconn.dh.g);

-				newf = newframe(frame, NCdhx, 0, 0, sizeof(ulong), nil);

+				newf = newframe(nil, NCdhx, frame->seq+1, frame->seq, sizeof(ulong), nil);

 				netconn.dh.sec = truerand();

 				pack(newf->data, newf->len, "k", dhgenkey(netconn.dh.g, netconn.dh.sec, netconn.dh.p));

@@ -290,7 +290,7 @@

 			}

 			break;

 		case NCSConnected:

-			if(verifyframe(frame, netconn.dh.priv) != 0){

+			if(!verifyframe(frame, netconn.dh.priv)){

 				if(debug)

 					fprint(2, "\tbad signature\n");

 				goto discard;

@@ -304,7 +304,7 @@

 					&universe->star.p);

 				break;

 			case NSnudge:

-				newf = newframe(frame, NCnudge, 0, 0, 0, nil);

+				newf = newframe(nil, NCnudge, frame->seq+1, frame->seq, 0, nil);

 				signframe(newf, netconn.dh.priv);

 				sendp(egress, newf);

--- a/muswd.c

+++ b/muswd.c

@@ -58,6 +58,32 @@

 }

 void

+nudgeconns(ulong curts)

+{

+	NetConn **ncp, **ncpe;

+	Frame *f;

+	ulong elapsed, elapsednudge;

+

+	ncpe = conns+nconns;

+

+	for(ncp = conns; ncp < ncpe; ncp++){

+		elapsed = curts - (*ncp)->lastrecvts;

+		elapsednudge = curts - (*ncp)->lastnudgets;

+

+		if((*ncp)->state == NCSConnected && elapsed > ConnTimeout){

+			popconn(*ncp);

+			delnetconn(*ncp);

+		}else if((*ncp)->state == NCSConnected && elapsednudge > 1000){ /* every second */

+			f = newframe(&(*ncp)->udp, NSnudge, 0, 0, 0, nil);

+			signframe(f, (*ncp)->dh.priv);

+			sendp(egress, f);

+

+			(*ncp)->lastnudgets = curts;

+		}

+	}

+}

+

+void

 threadnetrecv(void *arg)

 {

 	uchar buf[MTU];

@@ -105,7 +131,7 @@

 				nc = newnetconn(NCSConnecting, &frame->udp);

 				putconn(nc);

-				newf = newframe(frame, NShi, 0, 0, 2*sizeof(ulong), nil);

+				newf = newframe(&frame->udp, NShi, frame->seq+1, frame->seq, 2*sizeof(ulong), nil);

 				dhgenpg(&nc->dh.p, &nc->dh.g);

 				pack(newf->data, newf->len, "kk", nc->dh.p, nc->dh.g);

@@ -117,6 +143,8 @@

 				goto discard;

 		}

+		nc->lastrecvts = nanosec()/1e6;

+

 		switch(nc->state){

 		case NCSConnecting:

 			switch(frame->type){

@@ -127,7 +155,7 @@

 				if(debug)

 					fprint(2, "\trcvd pubkey %ld\n", nc->dh.pub);

-				newf = newframe(frame, NSdhx, 0, 0, sizeof(ulong), nil);

+				newf = newframe(&frame->udp, NSdhx, frame->seq+1, frame->seq, sizeof(ulong), nil);

 				nc->dh.sec = truerand();

 				nc->dh.priv = dhgenkey(nc->dh.pub, nc->dh.sec, nc->dh.p);

@@ -141,7 +169,7 @@

 			}

 			break;

 		case NCSConnected:

-			if(verifyframe(frame, nc->dh.priv) != 0){

+			if(!verifyframe(frame, nc->dh.priv)){

 				if(debug)

 					fprint(2, "\tbad signature\n");

 				goto discard;

@@ -250,6 +278,7 @@

 		}

 		broadcaststate();

+		nudgeconns(now/1e6);

 		iosleep(io, HZ2MS(70));

 	}

--- a/net.c

+++ b/net.c

@@ -66,23 +66,18 @@

 /* Frame */

 Frame *

-newframe(Frame *pf, u8int type, u32int seq, u32int ack, u16int len, uchar *data)

+newframe(Udphdr *hdr, u8int type, u32int seq, u32int ack, u16int len, uchar *data)

 {

 	Frame *f;

 	f = emalloc(sizeof(Frame)+len);

 	memset(f, 0, sizeof(Frame));

+	if(hdr != nil)

+		memmove(&f->udp, hdr, Udphdrsize);

 	f->id = ProtocolID;

 	f->type = type;

-	if(pf != nil){

-		memmove(&f->udp, &pf->udp, Udphdrsize);

-		f->seq = pf->seq+1;

-		f->ack = pf->seq;

-	}else{

-		memset(&f->udp, 0, Udphdrsize);

-		f->seq = seq;

-		f->ack = ack;

-	}

+	f->seq = seq;

+	f->ack = ack;

 	f->len = len;

 	if(data != nil)

 		memmove(f->data, data, f->len);

@@ -120,8 +115,7 @@

 	memset(f->sig, 0, MD5dlen);

 	n = pack(msg, sizeof msg, "f", f);

 	hmac_md5(msg, n, k, sizeof k, h1, nil);

-	memmove(f->sig, h0, MD5dlen);

-	return memcmp(h0, h1, MD5dlen);

+	return memcmp(h0, h1, MD5dlen) == 0;

 }

 void