From cb6dc39a5e5d2d981b4b1e983042b3fbb529d5d1 Mon Sep 17 00:00:00 2001
From: Leonardo Bras <leobras@redhat.com>
Date: Thu, 4 Aug 2022 04:10:43 -0300
Subject: [PATCH 06/11] QIOChannelSocket: Add support for MSG_ZEROCOPY + IPV6
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RH-Author: Leonardo Brás <leobras@redhat.com>
RH-MergeRequest: 111: zero-copy-send fixes & improvements
RH-Commit: [6/6] 2eb1aba8ebf267a6f67cfba2e489dc88619c7fd4 (LeoBras/centos-qemu-kvm)
RH-Bugzilla: 2107466
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

For using MSG_ZEROCOPY, there are two steps:
1 - io_writev() the packet, which enqueues the packet for sending, and
2 - io_flush(), which gets confirmation that all packets got correctly sent

Currently, if MSG_ZEROCOPY is used to send packets over IPV6, no error will
be reported in (1), but it will fail in the first time (2) happens.

This happens because (2) currently checks for cmsg_level & cmsg_type
associated with IPV4 only, before reporting any error.

Add checks for cmsg_level & cmsg_type associated with IPV6, and thus enable
support for MSG_ZEROCOPY + IPV6

Fixes: 2bc58ffc29 ("QIOChannelSocket: Implement io_writev zero copy flag & io_flush for CONFIG_LINUX")
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
(cherry picked from commit 5258a7e2c0677d16e9e1d06845f60171adf0b290)
Signed-off-by: Leonardo Bras <leobras@redhat.com>
---
 io/channel-socket.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/io/channel-socket.c b/io/channel-socket.c
index eb7baa2184..efd5f60808 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -747,8 +747,8 @@ static int qio_channel_socket_flush(QIOChannel *ioc,
         }
 
         cm = CMSG_FIRSTHDR(&msg);
-        if (cm->cmsg_level != SOL_IP &&
-            cm->cmsg_type != IP_RECVERR) {
+        if (cm->cmsg_level != SOL_IP   && cm->cmsg_type != IP_RECVERR &&
+            cm->cmsg_level != SOL_IPV6 && cm->cmsg_type != IPV6_RECVERR) {
             error_setg_errno(errp, EPROTOTYPE,
                              "Wrong cmsg in errqueue");
             return -1;
-- 
2.31.1