int
packetcopy(Packet *p, uint8_t *buf, int offset, int n)
{
uint8_t *b;
NOTFREE(p);
b = packetpeek(p, buf, offset, n);
if(b == nil)
return -1;
if(b != buf)
memmove(buf, b, n);
return 0;
}
static void
muxrpc(VtConn *z, Packet *p)
{
uchar tag, buf[2], *top;
Rwait *r;
if((top = packetpeek(p, buf, 0, 2)) == nil){
fprint(2, "libventi: short packet in vtrpc\n");
packetfree(p);
return;
}
tag = top[1];
if((r = z->wait[tag]) == nil){
fprint(2, "libventi: unexpected packet tag %d in vtrpc\n", tag);
abort();
packetfree(p);
return;
}
r->p = p;
r->done = 1;
rwakeup(&r->r);
}
Packet*
_vtrpc(VtConn *z, Packet *p, VtFcall *tx)
{
int i;
uchar tag, buf[2], *top;
Rwait *r, *rr;
/* must malloc because stack could be private */
r = vtmallocz(sizeof(Rwait));
qlock(&z->lk);
r->r.l = &z->lk;
tag = gettag(z, r);
if(tx){
/* vtfcallrpc can't print packet because it doesn't have tag */
tx->tag = tag;
if(chattyventi)
fprint(2, "%s -> %F\n", argv0, tx);
}
/* slam tag into packet */
top = packetpeek(p, buf, 0, 2);
if(top == nil){
packetfree(p);
return nil;
}
if(top == buf){
werrstr("first two bytes must be in same packet fragment");
packetfree(p);
vtfree(r);
return nil;
}
top[1] = tag;
qunlock(&z->lk);
if(vtsend(z, p) < 0){
vtfree(r);
return nil;
}
qlock(&z->lk);
/* wait for the muxer to give us our packet */
r->sleeping = 1;
z->nsleep++;
while(z->muxer && !r->done)
rsleep(&r->r);
z->nsleep--;
r->sleeping = 0;
/* if not done, there's no muxer: start muxing */
if(!r->done){
if(z->muxer)
abort();
z->muxer = 1;
while(!r->done){
qunlock(&z->lk);
if((p = vtrecv(z)) == nil){
werrstr("unexpected eof on venti connection");
z->muxer = 0;
vtfree(r);
return nil;
}
qlock(&z->lk);
muxrpc(z, p);
}
z->muxer = 0;
/* if there is anyone else sleeping, wake first unfinished to mux */
if(z->nsleep)
for(i=0; i<256; i++){
rr = z->wait[i];
if(rr && rr->sleeping && !rr->done){
rwakeup(&rr->r);
break;
}
}
}
p = r->p;
puttag(z, r, tag);
vtfree(r);
qunlock(&z->lk);
return p;
}