dpif-netdev: use dpif_packet structure for packets

This commit introduces a new data structure used for receiving packets from
netdevs and passing them to dpifs.
The purpose of this change is to allow storing some private data for each
packet. The subsequent commits make use of it.

Signed-off-by: Daniele Di Proietto <ddiproietto@vmware.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>

lib/packet-dpif.c

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2014 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 "packet-dpif.h"
+
+#include "ofpbuf.h"
+
+struct dpif_packet *
+dpif_packet_new_with_headroom(size_t size, size_t headroom)
+{
+    struct dpif_packet *p = xmalloc(sizeof *p);
+    struct ofpbuf *b = &p->ofpbuf;
+
+    ofpbuf_init(b, size + headroom);
+    ofpbuf_reserve(b, headroom);
+
+    return p;
+}
+
+struct dpif_packet *
+dpif_packet_clone_from_ofpbuf(const struct ofpbuf *b)
+{
+    struct dpif_packet *p = xmalloc(sizeof *p);
+    size_t headroom = ofpbuf_headroom(b);
+
+    ofpbuf_init(&p->ofpbuf, ofpbuf_size(b) + headroom);
+    ofpbuf_reserve(&p->ofpbuf, headroom);
+
+    ofpbuf_put(&p->ofpbuf, ofpbuf_data(b), ofpbuf_size(b));
+
+    if (b->frame) {
+        uintptr_t data_delta
+            = (char *)ofpbuf_data(&p->ofpbuf) - (char *)ofpbuf_data(b);
+
+        p->ofpbuf.frame = (char *) b->frame + data_delta;
+    }
+    p->ofpbuf.l2_5_ofs = b->l2_5_ofs;
+    p->ofpbuf.l3_ofs = b->l3_ofs;
+    p->ofpbuf.l4_ofs = b->l4_ofs;
+
+    return p;
+}
+
+struct dpif_packet *
+dpif_packet_clone(struct dpif_packet *p)
+{
+    struct dpif_packet *newp;
+
+    newp = dpif_packet_clone_from_ofpbuf(&p->ofpbuf);
+
+    return newp;
+}