4 files changed, 51 insertions(+), 9 deletions(-)

M ip/devip.c
M ip/ip.h
M ip/ipifc.c
M ip/pktmedium.c

@@ 32,6 32,7 @@ enum
 	Qlocal,
 	Qremote,
 	Qstatus,
+	Qsnoop,
 
 	Logtype=	5,
 	Masktype=	(1<<Logtype)-1,


@@ 84,7 85,7 @@ ip3gen(Chan *c, int i, Dir *dp)
 		devdir(c, q, "err", qlen(cv->eq), cv->owner, cv->perm, dp);
 		return 1;
 	case Qlisten:
-		devdir(c, q, "listen", qlen(cv->eq), cv->owner, cv->perm, dp);
+		devdir(c, q, "listen", 0, cv->owner, cv->perm, dp);
 		return 1;
 	case Qlocal:
 		p = "local";


@@ 92,6 93,11 @@ ip3gen(Chan *c, int i, Dir *dp)
 	case Qremote:
 		p = "remote";
 		break;
+	case Qsnoop:
+		if(strcmp(cv->p->name, "ipifc") != 0)
+			return -1;
+		devdir(c, q, "snoop", qlen(cv->sq), cv->owner, 0400, dp);
+		return 1;
 	case Qstatus:
 		p = "status";
 		break;


@@ 235,6 241,7 @@ ipgen(Chan *c, char*, Dirtab*, int, int s, Dir *dp)
 	case Qlocal:
 	case Qremote:
 	case Qstatus:
+	case Qsnoop:
 		return ip3gen(c, TYPE(c->qid), dp);
 	}
 	return -1;


@@ 391,6 398,15 @@ ipopen(Chan* c, int omode)
 		if(omode != OREAD)
 			error(Eperm);
 		break;
+	case Qsnoop:
+		if(omode != OREAD)
+			error(Eperm);
+		p = f->p[PROTO(c->qid)];
+		cv = p->conv[CONV(c->qid)];
+		if(strcmp(ATTACHER(c), cv->owner) != 0 && !iseve())
+			error(Eperm);
+		incref(&cv->snoopers);
+		break;
 	case Qclone:
 		p = f->p[PROTO(c->qid)];
 		qlock(p);


@@ 575,6 591,11 @@ ipclose(Chan* c)
 	case Qerr:
 		if(c->flag & COPEN)
 			closeconv(f->p[PROTO(c->qid)]->conv[CONV(c->qid)]);
+		break;
+	case Qsnoop:
+		if(c->flag & COPEN)
+			decref(&f->p[PROTO(c->qid)]->conv[CONV(c->qid)]->snoopers);
+		break;
 	}
 	free(((IPaux*)c->aux)->owner);
 	free(c->aux);


@@ 663,6 684,9 @@ ipread(Chan *ch, void *a, long n, vlong off)
 	case Qerr:
 		c = f->p[PROTO(ch->qid)]->conv[CONV(ch->qid)];
 		return qread(c->eq, a, n);
+	case Qsnoop:
+		c = f->p[PROTO(ch->qid)]->conv[CONV(ch->qid)];
+		return qread(c->sq, a, n);
 	case Qstats:
 		x = f->p[PROTO(ch->qid)];
 		if(x->stats == nil)

@@ 105,6 105,8 @@ struct Conv
 	Queue*	rq;			/* queued data waiting to be read */
 	Queue*	wq;			/* queued data waiting to be written */
 	Queue*	eq;			/* returned error packets */
+	Queue*	sq;			/* snooping queue */
+	Ref	snoopers;		/* number of processes with snoop open */
 
 	QLock	car;
 	Rendez	cr;

@@ 128,18 128,22 @@ ipifcbind(Conv *c, char **argv, int argc)
 		nexterror();
 	}
 
+	/* do medium specific binding */
 	(*m->bind)(ifc, argc, argv);
+
+	/* set the bound device name */
 	if(argc > 2)
 		strncpy(ifc->dev, argv[2], sizeof(ifc->dev));
 	else
 		sprint(ifc->dev, "%s%d", m->name, c->x);
 	ifc->dev[sizeof(ifc->dev)-1] = 0;
+
+	/* set up parameters */
 	ifc->m = m;
 	ifc->minmtu = ifc->m->minmtu;
 	ifc->maxmtu = ifc->m->maxmtu;
 	if(ifc->m->unbindonclose == 0)
 		ifc->conv->inuse++;
-
 	ifc->rp.mflag	= 0;		// default not managed
 	ifc->rp.oflag	= 0;
 	ifc->rp.maxraint	= 600000;	// millisecs


@@ 148,10 152,16 @@ ipifcbind(Conv *c, char **argv, int argc)
 	ifc->rp.reachtime	= 0;
 	ifc->rp.rxmitra	= 0;
 	ifc->rp.ttl	= MAXTTL;
-	ifc->rp.routerlt	= 3*(ifc->rp.maxraint);	
+	ifc->rp.routerlt	= 3*(ifc->rp.maxraint);
 
+	/* any ancillary structures (like routes) no longer pertain */
 	ifc->ifcid++;
 
+	/* reopen all the queues closed by a previous unbind */
+	qreopen(c->rq);
+	qreopen(c->eq);
+	qreopen(c->sq);
+
 	wunlock(ifc);
 	poperror();
 


@@ 188,9 198,10 @@ ipifcunbind(Ipifc *ifc)
 	ifc->arg = nil;
 	ifc->reassemble = 0;
 
-	/* hangup queues to stop queuing of packets */
-	qhangup(ifc->conv->rq, "unbind");
-	qhangup(ifc->conv->wq, "unbind");
+	/* close queues to stop queuing of packets */
+	qclose(ifc->conv->rq);
+	qclose(ifc->conv->wq);
+	qclose(ifc->conv->sq);
 
 	/* disassociate logical interfaces */
 	av[0] = "remove";


@@ 301,8 312,7 @@ ipifckick(void *x)
 }
 
 /*
- *  we'll have to have a kick routine at
- *  some point to deal with these
+ *  called when a new ipifc structure is created
  */
 static void
 ipifccreate(Conv *c)


@@ 310,6 320,7 @@ ipifccreate(Conv *c)
 	Ipifc *ifc;
 
 	c->rq = qopen(QMAX, 0, 0, 0);
+	c->sq = qopen(2*QMAX, 0, 0, 0);
 	c->wq = qopen(QMAX, Qkick, ipifckick, c);
 	ifc = (Ipifc*)c->ptcl;
 	ifc->conv = c;

@@ 52,6 52,8 @@ pktbwrite(Ipifc *ifc, Block *bp, int, uchar*)
 {
 	/* enqueue onto the conversation's rq */
 	bp = concatblock(bp);
+	if(ifc->conv->snoopers.ref > 0)
+		qpass(ifc->conv->sq, copyblock(bp, BLEN(bp)));
 	qpass(ifc->conv->rq, bp);
 }
 


@@ 63,8 65,11 @@ pktin(Fs *f, Ipifc *ifc, Block *bp)
 {
 	if(ifc->lifc == nil)
 		freeb(bp);
-	else
+	else {
+		if(ifc->conv->snoopers.ref > 0)
+			qpass(ifc->conv->sq, copyblock(bp, BLEN(bp)));
 		ipiput4(f, ifc, bp);
+	}
 }
 
 void