dirfstat on tcp/udp/il connections is always 0

[presotto@plan9.att.com presotto@plan9.att.com]

Since dirfstat returns the size of the next message queued
for reading for pipes, it would be nice if the same happened
for IP protocols.  The following changes make it work.
Note that dirstat will still return 0 (the stream gets bound
to the fd on open...).

--------------------------------------------
In port/stream.c, replace streamstat() with:
--------------------------------------------

ulong
streamlen(Chan *c)
{
	Stream *s;
	Queue *q;
	Block *bp;
	ulong n;

	s = c->stream;
	n = 0;
	if(s) {
		q = RD(s->procq);
		if(q->flag & QHUNGUP)
			error(Ehungup);
		lock(q);
		for(bp=q->first; bp; bp = bp->next){
			n += BLEN(bp);
			if(bp->flags&S_DELIM)
				break;
		}
		unlock(q);
	}
	return n;
}
void
streamstat(Chan *c, char *db, char *name, long perm)
{
	Dir dir;

	devdir(c, c->qid, name, streamlen(c), eve, perm, &dir);
	convD2M(&dir, db);
}

--------------------------------------------
In port/net.c
--------------------------------------------

% diff net.c $old/net.c
93c93
< 		devdir(c, q, "data", streamlen(c), o, perm, dp);
---
> 		devdir(c, q, "data", 0, o, perm, dp);

--------------------------------------------
In port/portfns.h
--------------------------------------------

% diff portfns.h $old/portfns.h
267d266
< ulong		streamlen(Chan*);