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Handle TFTP ERROR from client

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If a PXE client only wants to find out the size of a file, it will
open the file and then abort the transfer by sending a TFTP ERROR packet.

The ERROR packet should cause qemu to terminate the session. If not,
the sessions will soon run out and cause timeouts in the client.

Also, if a TFTP session already exists with same IP/UDP port, it
should be terminated when a new RRQ is received, instead of creating a
duplicate (which will never be used).

A patch for gPXE to send the ERROR packet is also being submitted to
gPXE. Together they resolve slowness/hanging when booting pxegrub from
qemu's internal TFTP server. The patch from Milan Plzik to return
after sending OACK is also required for a complete fix.

Signed-off-by: Thomas Horsten <thomas@horsten.com>
Signed-off-by: Milan Plzik <milan.plzik@gmail.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Thomas Horsten 2010-01-07 17:01:28 +00:00 committed by Anthony Liguori
parent 1559ca00bc
commit bfe4e17242
1 changed files with 23 additions and 0 deletions
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23
slirp/tftp.c
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@ -264,6 +264,12 @@ static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
size_t prefix_len;
char *req_fname;
/* check if a session already exists and if so terminate it */
s = tftp_session_find(slirp, tp);
if (s >= 0) {
tftp_session_terminate(&slirp->tftp_sessions[s]);
}
s = tftp_session_allocate(slirp, tp);
if (s < 0) {
@ -385,6 +391,19 @@ static void tftp_handle_ack(Slirp *slirp, struct tftp_t *tp, int pktlen)
}
}
static void tftp_handle_error(Slirp *slirp, struct tftp_t *tp, int pktlen)
{
int s;
s = tftp_session_find(slirp, tp);
if (s < 0) {
return;
}
tftp_session_terminate(&slirp->tftp_sessions[s]);
}
void tftp_input(struct mbuf *m)
{
struct tftp_t *tp = (struct tftp_t *)m->m_data;
@ -397,5 +416,9 @@ void tftp_input(struct mbuf *m)
case TFTP_ACK:
tftp_handle_ack(m->slirp, tp, m->m_len);
break;
case TFTP_ERROR:
tftp_handle_error(m->slirp, tp, m->m_len);
break;
}
}