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tftp: prevent it from hanging if ack packets get lost

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send ACK reply for duplicate data packets in case our ack response
got lost. make sure packets are in sequence and ignore out of
oder packets (except the ones we'v already acked).
This commit is contained in:
cinap_lenrek 2012-09-20 09:33:40 +02:00
parent 9d182f906d
commit 9a06f93b71
3 changed files with 38 additions and 32 deletions
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15
sys/src/boot/pc/pxe.c
View file

@ -249,16 +249,21 @@ read(void *f, void *data, int len)
switch(nhgets(t->pkt)){
case Tftp_DATA:
seq = nhgets(t->pkt+2);
if(seq <= t->seq){
putc('@');
if(seq > t->seq){
putc('?');
continue;
}
hnputs(t->pkt, Tftp_ACK);
while(udpwrite(t->dip, t->gip, t->sport, t->dport, 4, t->pkt))
putc('!');
t->seq = seq;
if(seq < t->seq){
putc('@');
continue;
}
t->seq = seq+1;
n -= 4;
t->rp = t->pkt + 4;
t->ep = t->pkt + n;
t->ep = t->rp + n;
t->eof = n < Segsize;
break;
case Tftp_ERROR:
@ -300,7 +305,7 @@ tftpopen(Tftp *t, char *path, IP4 sip, IP4 dip, IP4 gip)
t->sport = xport++;
t->dport = 0;
t->rp = t->ep = 0;
t->seq = -1;
t->seq = 1;
t->eof = 0;
t->nul = 0;
if(r = udpopen(t->sip))

3
sys/src/cmd/ip/tftpd.c
View file

@ -340,9 +340,6 @@ options(int fd, char *buf, int bufsz, char *file, ushort oper, char *p, int dlen
if (nopts == 0)
return 0; /* no options actually seen */
if (bp + 3 >= ep)
return -1;
if (write(fd, buf, bp - buf) < bp - buf) {
syslog(dbg, flog, "tftpd network write error on oack to %s: %r",
raddr);

52
sys/src/cmd/ip/tftpfs.c
View file

@ -147,7 +147,7 @@ filereq(uchar *buf, char *path)
static void
download(void *aux)
{
int fd, cfd, last, block, n, ndata;
int fd, cfd, last, block, seq, n, ndata;
char *err, adir[40];
uchar *data;
Channel *c;
@ -197,6 +197,7 @@ download(void *aux)
notify(catch);
seq = 1;
last = 0;
while(!last){
alarm(5000);
@ -218,34 +219,37 @@ download(void *aux)
if(n < 4)
continue;
block = nhgets(msg.buf+2);
if((n -= 4) > 0){
data = erealloc9p(data, ndata + n);
memcpy(data + ndata, msg.buf+4, n);
ndata += n;
rloop: /* hanlde read request while downloading */
if((r != nil) && (r->ifcall.type == Tread) && (r->ifcall.offset < ndata)){
readbuf(r, data, ndata);
respond(r, nil);
r = nil;
}
if((r == nil) && (nbrecv(c, &r) == 1)){
if(r == nil){
chanfree(c);
c = nil;
goto out;
}
goto rloop;
}
}
if(n < Segsize)
last = 1;
if(block > seq)
continue;
hnputs(msg.buf, Tftp_ACK);
hnputs(msg.buf+2, block);
if(write(fd, &msg, sizeof(Udphdr) + 4) < 0){
err = "send acknowledge: %r";
goto out;
}
if(block < seq)
continue;
seq = block+1;
n -= 4;
if(n < Segsize)
last = 1;
data = erealloc9p(data, ndata + n);
memcpy(data + ndata, msg.buf+4, n);
ndata += n;
rloop: /* hanlde read request while downloading */
if((r != nil) && (r->ifcall.type == Tread) && (r->ifcall.offset < ndata)){
readbuf(r, data, ndata);
respond(r, nil);
r = nil;
}
if((r == nil) && (nbrecv(c, &r) == 1)){
if(r == nil){
chanfree(c);
c = nil;
goto out;
}
goto rloop;
}
break;
}
}