migration: Enable TLS for preempt channel

This patch is based on the async preempt channel creation.  It continues
wiring up the new channel with TLS handshake to destionation when enabled.

Note that only the src QEMU needs such operation; the dest QEMU does not
need any change for TLS support due to the fact that all channels are
established synchronously there, so all the TLS magic is already properly
handled by migration_tls_channel_process_incoming().

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20220707185518.27529-1-peterx@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 49 insertions, 8 deletions

diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 70b21e9d51..b9a37ef255 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -36,6 +36,7 @@
 #include "socket.h"
 #include "qemu-file.h"
 #include "yank_functions.h"
+#include "tls.h"
 
 /* Arbitrary limit on size of each discard command,
  * keeps them around ~200 bytes
@@ -1552,15 +1553,15 @@ bool postcopy_preempt_new_channel(MigrationIncomingState *mis, QEMUFile *file)
     return true;
 }
 
+/*
+ * Setup the postcopy preempt channel with the IOC.  If ERROR is specified,
+ * setup the error instead.  This helper will free the ERROR if specified.
+ */
 static void
-postcopy_preempt_send_channel_new(QIOTask *task, gpointer opaque)
+postcopy_preempt_send_channel_done(MigrationState *s,
+                                   QIOChannel *ioc, Error *local_err)
 {
-    MigrationState *s = opaque;
-    QIOChannel *ioc = QIO_CHANNEL(qio_task_get_source(task));
-    Error *local_err = NULL;
-
-    if (qio_task_propagate_error(task, &local_err)) {
-        /* Something wrong happened.. */
+    if (local_err) {
         migrate_set_error(s, local_err);
         error_free(local_err);
     } else {
@@ -1574,7 +1575,47 @@ postcopy_preempt_send_channel_new(QIOTask *task, gpointer opaque)
      * postcopy_qemufile_src to know whether it failed or not.
      */
     qemu_sem_post(&s->postcopy_qemufile_src_sem);
-    object_unref(OBJECT(ioc));
+}
+
+static void
+postcopy_preempt_tls_handshake(QIOTask *task, gpointer opaque)
+{
+    g_autoptr(QIOChannel) ioc = QIO_CHANNEL(qio_task_get_source(task));
+    MigrationState *s = opaque;
+    Error *local_err = NULL;
+
+    qio_task_propagate_error(task, &local_err);
+    postcopy_preempt_send_channel_done(s, ioc, local_err);
+}
+
+static void
+postcopy_preempt_send_channel_new(QIOTask *task, gpointer opaque)
+{
+    g_autoptr(QIOChannel) ioc = QIO_CHANNEL(qio_task_get_source(task));
+    MigrationState *s = opaque;
+    QIOChannelTLS *tioc;
+    Error *local_err = NULL;
+
+    if (qio_task_propagate_error(task, &local_err)) {
+        goto out;
+    }
+
+    if (migrate_channel_requires_tls_upgrade(ioc)) {
+        tioc = migration_tls_client_create(s, ioc, s->hostname, &local_err);
+        if (!tioc) {
+            goto out;
+        }
+        trace_postcopy_preempt_tls_handshake();
+        qio_channel_set_name(QIO_CHANNEL(tioc), "migration-tls-preempt");
+        qio_channel_tls_handshake(tioc, postcopy_preempt_tls_handshake,
+                                  s, NULL, NULL);
+        /* Setup the channel until TLS handshake finished */
+        return;
+    }
+
+out:
+    /* This handles both good and error cases */
+    postcopy_preempt_send_channel_done(s, ioc, local_err);
 }
 
 /* Returns 0 if channel established, -1 for error. */