colo-compare: track connection and enqueue packet

In this patch we use kernel jhash table to track
connection, and then enqueue net packet like this:

+ CompareState ++
|               |
+---------------+   +---------------+         +---------------+
|conn list      +--->conn           +--------->conn           |
+---------------+   +---------------+         +---------------+
|               |     |           |             |          |
+---------------+ +---v----+  +---v----+    +---v----+ +---v----+
                  |primary |  |secondary    |primary | |secondary
                  |packet  |  |packet  +    |packet  | |packet  +
                  +--------+  +--------+    +--------+ +--------+
                      |           |             |          |
                  +---v----+  +---v----+    +---v----+ +---v----+
                  |primary |  |secondary    |primary | |secondary
                  |packet  |  |packet  +    |packet  | |packet  +
                  +--------+  +--------+    +--------+ +--------+
                      |           |             |          |
                  +---v----+  +---v----+    +---v----+ +---v----+
                  |primary |  |secondary    |primary | |secondary
                  |packet  |  |packet  +    |packet  | |packet  +
                  +--------+  +--------+    +--------+ +--------+

We use conn_list to record connection info.
When we want to enqueue a packet, firstly get the
connection from connection_track_table. then push
the packet to g_queue(pri/sec) in it's own conn.

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

@@ -16,6 +16,29 @@
 #include "trace.h"
 #include "net/colo.h"
 
+uint32_t connection_key_hash(const void *opaque)
+{
+    const ConnectionKey *key = opaque;
+    uint32_t a, b, c;
+
+    /* Jenkins hash */
+    a = b = c = JHASH_INITVAL + sizeof(*key);
+    a += key->src.s_addr;
+    b += key->dst.s_addr;
+    c += (key->src_port | key->dst_port << 16);
+    __jhash_mix(a, b, c);
+
+    a += key->ip_proto;
+    __jhash_final(a, b, c);
+
+    return c;
+}
+
+int connection_key_equal(const void *key1, const void *key2)
+{
+    return memcmp(key1, key2, sizeof(ConnectionKey)) == 0;
+}
+
 int parse_packet_early(Packet *pkt)
 {
     int network_length;
@@ -59,6 +82,61 @@ int parse_packet_early(Packet *pkt)
     return 0;
 }
 
+void fill_connection_key(Packet *pkt, ConnectionKey *key)
+{
+    uint32_t tmp_ports;
+
+    memset(key, 0, sizeof(*key));
+    key->ip_proto = pkt->ip->ip_p;
+
+    switch (key->ip_proto) {
+    case IPPROTO_TCP:
+    case IPPROTO_UDP:
+    case IPPROTO_DCCP:
+    case IPPROTO_ESP:
+    case IPPROTO_SCTP:
+    case IPPROTO_UDPLITE:
+        tmp_ports = *(uint32_t *)(pkt->transport_header);
+        key->src = pkt->ip->ip_src;
+        key->dst = pkt->ip->ip_dst;
+        key->src_port = ntohs(tmp_ports & 0xffff);
+        key->dst_port = ntohs(tmp_ports >> 16);
+        break;
+    case IPPROTO_AH:
+        tmp_ports = *(uint32_t *)(pkt->transport_header + 4);
+        key->src = pkt->ip->ip_src;
+        key->dst = pkt->ip->ip_dst;
+        key->src_port = ntohs(tmp_ports & 0xffff);
+        key->dst_port = ntohs(tmp_ports >> 16);
+        break;
+    default:
+        break;
+    }
+}
+
+Connection *connection_new(ConnectionKey *key)
+{
+    Connection *conn = g_slice_new(Connection);
+
+    conn->ip_proto = key->ip_proto;
+    conn->processing = false;
+    g_queue_init(&conn->primary_list);
+    g_queue_init(&conn->secondary_list);
+
+    return conn;
+}
+
+void connection_destroy(void *opaque)
+{
+    Connection *conn = opaque;
+
+    g_queue_foreach(&conn->primary_list, packet_destroy, NULL);
+    g_queue_free(&conn->primary_list);
+    g_queue_foreach(&conn->secondary_list, packet_destroy, NULL);
+    g_queue_free(&conn->secondary_list);
+    g_slice_free(Connection, conn);
+}
+
 Packet *packet_new(const void *data, int size)
 {
     Packet *pkt = g_slice_new(Packet);
@@ -84,3 +162,33 @@ void connection_hashtable_reset(GHashTable *connection_track_table)
 {
     g_hash_table_remove_all(connection_track_table);
 }
+
+/* if not found, create a new connection and add to hash table */
+Connection *connection_get(GHashTable *connection_track_table,
+                           ConnectionKey *key,
+                           GQueue *conn_list)
+{
+    Connection *conn = g_hash_table_lookup(connection_track_table, key);
+
+    if (conn == NULL) {
+        ConnectionKey *new_key = g_memdup(key, sizeof(*key));
+
+        conn = connection_new(key);
+
+        if (g_hash_table_size(connection_track_table) > HASHTABLE_MAX_SIZE) {
+            trace_colo_proxy_main("colo proxy connection hashtable full,"
+                                  " clear it");
+            connection_hashtable_reset(connection_track_table);
+            /*
+             * clear the conn_list
+             */
+            while (!g_queue_is_empty(conn_list)) {
+                connection_destroy(g_queue_pop_head(conn_list));
+            }
+        }
+
+        g_hash_table_insert(connection_track_table, new_key, conn);
+    }
+
+    return conn;
+}