From a6c4aed18a027ce8e107fdf9184e9ea43a86f843 Mon Sep 17 00:00:00 2001
From: Leonardo Bras <leobras@redhat.com>
Date: Thu, 4 Aug 2022 04:10:43 -0300
Subject: [PATCH 8/9] QIOChannelSocket: Add support for MSG_ZEROCOPY + IPV6
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RH-Author: Leonardo Brás <leobras@redhat.com>
RH-MergeRequest: 201: Zero-copy-send fixes + improvements
RH-Commit: [8/8] 6e26ee7c9ebaedb07623313cb0678816867751dd
RH-Bugzilla: 2110203
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@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 cf0d67c51b..6010ad7017 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