net/colo.c: add colo.c to define and handle packet

The net/colo.c is used by colo-compare and filter-rewriter.
this can share common data structure like net packet,
and other functions.

Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

net/colo.c

@@ -0,0 +1,86 @@
+/*
+ * COarse-grain LOck-stepping Virtual Machines for Non-stop Service (COLO)
+ * (a.k.a. Fault Tolerance or Continuous Replication)
+ *
+ * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
+ * Copyright (c) 2016 FUJITSU LIMITED
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * Author: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "trace.h"
+#include "net/colo.h"
+
+int parse_packet_early(Packet *pkt)
+{
+    int network_length;
+    static const uint8_t vlan[] = {0x81, 0x00};
+    uint8_t *data = pkt->data;
+    uint16_t l3_proto;
+    ssize_t l2hdr_len = eth_get_l2_hdr_length(data);
+
+    if (pkt->size < ETH_HLEN) {
+        trace_colo_proxy_main("pkt->size < ETH_HLEN");
+        return 1;
+    }
+
+    /*
+     * TODO: support vlan.
+     */
+    if (!memcmp(&data[12], vlan, sizeof(vlan))) {
+        trace_colo_proxy_main("COLO-proxy don't support vlan");
+        return 1;
+    }
+
+    pkt->network_header = data + l2hdr_len;
+
+    const struct iovec l2vec = {
+        .iov_base = (void *) data,
+        .iov_len = l2hdr_len
+    };
+    l3_proto = eth_get_l3_proto(&l2vec, 1, l2hdr_len);
+
+    if (l3_proto != ETH_P_IP) {
+        return 1;
+    }
+
+    network_length = pkt->ip->ip_hl * 4;
+    if (pkt->size < l2hdr_len + network_length) {
+        trace_colo_proxy_main("pkt->size < network_header + network_length");
+        return 1;
+    }
+    pkt->transport_header = pkt->network_header + network_length;
+
+    return 0;
+}
+
+Packet *packet_new(const void *data, int size)
+{
+    Packet *pkt = g_slice_new(Packet);
+
+    pkt->data = g_memdup(data, size);
+    pkt->size = size;
+
+    return pkt;
+}
+
+void packet_destroy(void *opaque, void *user_data)
+{
+    Packet *pkt = opaque;
+
+    g_free(pkt->data);
+    g_slice_free(Packet, pkt);
+}
+
+/*
+ * Clear hashtable, stop this hash growing really huge
+ */
+void connection_hashtable_reset(GHashTable *connection_track_table)
+{
+    g_hash_table_remove_all(connection_track_table);
+}