From: Kevin Cernekee <cernekee@chromium.org>
Date: Wed, 20 Sep 2017 20:42:05 +0000 (-0700)
Subject: slirp: Add a special case for the NULL socket
X-Git-Tag: v2.11.0-rc0~82^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=13146a83951e045c810c37c5c11c2a016ebc0663;p=thirdparty%2Fqemu.git

slirp: Add a special case for the NULL socket

NULL sockets are used for NDP, BOOTP, and other critical operations.
If the topmost mbuf in a NULL session is blocked pending resolution,
it may cause problems if it blocks other packets with a NULL socket.
So do not add mbufs with a NULL socket field to the same session.

Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
---

diff --git a/slirp/if.c b/slirp/if.c
index 6262d774956..590753c6582 100644
--- a/slirp/if.c
+++ b/slirp/if.c
@@ -73,14 +73,16 @@ if_output(struct socket *so, struct mbuf *ifm)
 	 * We mustn't put this packet back on the fastq (or we'll send it out of order)
 	 * XXX add cache here?
 	 */
-	for (ifq = (struct mbuf *) slirp->if_batchq.qh_rlink;
-	     (struct quehead *) ifq != &slirp->if_batchq;
-	     ifq = ifq->ifq_prev) {
-		if (so == ifq->ifq_so) {
-			/* A match! */
-			ifm->ifq_so = so;
-			ifs_insque(ifm, ifq->ifs_prev);
-			goto diddit;
+	if (so) {
+		for (ifq = (struct mbuf *) slirp->if_batchq.qh_rlink;
+		     (struct quehead *) ifq != &slirp->if_batchq;
+		     ifq = ifq->ifq_prev) {
+			if (so == ifq->ifq_so) {
+				/* A match! */
+				ifm->ifq_so = so;
+				ifs_insque(ifm, ifq->ifs_prev);
+				goto diddit;
+			}
 		}
 	}