ovsdb: Introduce experimental support for clustered databases.

This commit adds support for OVSDB clustering via Raft.  Please read
ovsdb(7) for information on how to set up a clustered database.  It is
simple and boils down to running "ovsdb-tool create-cluster" on one server
and "ovsdb-tool join-cluster" on each of the others and then starting
ovsdb-server in the usual way on all of them.

One you have a clustered database, you configure ovn-controller and
ovn-northd to use it by pointing them to all of the servers, e.g. where
previously you might have said "tcp:1.2.3.4" was the database server,
now you say that it is "tcp:1.2.3.4,tcp:5.6.7.8,tcp:9.10.11.12".

This also adds support for database clustering to ovs-sandbox.

Acked-by: Justin Pettit <jpettit@ovn.org>
Tested-by: aginwala <aginwala@asu.edu>
Signed-off-by: Ben Pfaff <blp@ovn.org>

1 files changed, 76 insertions, 0 deletions

diff --git a/lib/ovsdb-session.c b/lib/ovsdb-session.c
new file mode 100644
index 000000000..a8cb90f22
--- /dev/null
+++ b/lib/ovsdb-session.c
@@ -0,0 +1,76 @@
+/* Copyright (c) 2017 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+#include "ovsdb-session.h"
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+#include "svec.h"
+#include "util.h"
+#include "uuid.h"
+
+static const char *
+next_remote(const char *s)
+{
+    for (const char *delimiter = strchr(s, ','); delimiter;
+         delimiter = strchr(delimiter + 1, ',')) {
+        const char *p = delimiter + 1;
+        p += strspn(p, " \t");
+        size_t n_letters = strspn(p, "abcdefghijklmnopqrstuvwxyz");
+        if (n_letters && p[n_letters] == ':') {
+            return delimiter;
+        }
+    }
+    return NULL;
+}
+
+/* Parses string 's' into comma-delimited substrings and adds each of them into
+ * 'remotes'.  If one of the substrings is of the form "cid:<uuid>", fills
+ * '*cid' with the UUID (and omits it from 'remotes'), otherwise initializes
+ * '*cid' to UUID_ZERO. */
+void
+ovsdb_session_parse_remote(const char *s,
+                           struct svec *remotes, struct uuid *cid)
+{
+    *cid = UUID_ZERO;
+    for (;;) {
+        /* Skip white space. */
+        s += strspn(s, " \t");
+        if (*s == '\0') {
+            break;
+        }
+
+        /* Find the start of the next remote  */
+        const char *delimiter = next_remote(s);
+        if (!delimiter) {
+            svec_add(remotes, s);
+            break;
+        }
+        svec_add_nocopy(remotes, xmemdup0(s, delimiter - s));
+        s = delimiter + 1;
+    }
+
+    size_t i;
+    for (i = 0; i < remotes->n; i++) {
+        const char *name = remotes->names[i];
+        struct uuid uuid;
+        if (!strncmp(name, "cid:", 4) && uuid_from_string(&uuid, name + 4)) {
+            *cid = uuid;
+            svec_del(remotes, name);
+            break;
+        }
+    }
+}