DHCP Multiple Servers (VPP-602, VPP-605)

Multiple DHCP (4 and/or 6) servers can be added and removed through multiple calls to the 'set dhcp server' API.
All 4/6/ discover/solicit messages will then be replicated to all servers in the list. The expectation is that the servers/system is configured in such a way that this is viable.
If VSS information is providied for the clinet VRF which also has multiple servers configured, then the same VSS information is sent to each server. Likewise the source address of packets sent to from VPP to each server is the same.

Change-Id: I3287cb084c84b3f612b78bc69cfcb5b9c1f8934d
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 62 insertions, 23 deletions

diff --git a/src/vnet/dhcp/dhcp_proxy.h b/src/vnet/dhcp/dhcp_proxy.h
index 708e92f3c32..ef2bc0a1926 100644
--- a/src/vnet/dhcp/dhcp_proxy.h
+++ b/src/vnet/dhcp/dhcp_proxy.h
@@ -58,9 +58,10 @@ typedef struct dhcp_vss_t_ {
 } dhcp_vss_t;
 
 /**
- * @brief A DHCP proxy server represenation
+ * @brief A representation of a single DHCP Server within a given VRF config
  */
-typedef struct dhcp_server_t_ {
+typedef struct dhcp_server_t_
+{
     /**
      * @brief The address of the DHCP server to which to relay the client's
      *        messages
@@ -68,22 +69,47 @@ typedef struct dhcp_server_t_ {
     ip46_address_t dhcp_server;
 
     /**
-     * @brief The source address to use in relayed messaes
-     */
-    ip46_address_t dhcp_src_address;
-
-    /**
      * @brief The FIB index (not the external Table-ID) in which the server
      *        is reachable.
      */
     u32 server_fib_index;
+} dhcp_server_t;
+
+/**
+ * @brief A DHCP proxy represenation fpr per-client VRF config
+ */
+typedef struct dhcp_proxy_t_ {
+    /**
+     * @brief The set of DHCP servers to which messages are relayed.
+     *  If multiple servers are configured then discover/solict messages
+     * are relayed to each. A cookie is maintained for the relay, and only
+     * one message is replayed to the client, based on the presence of the
+     * cookie.
+     * The expectation is there are only 1 or 2 servers, hence no fancy DB.
+     */
+    dhcp_server_t *dhcp_servers;
+
+    /**
+     * @brief Hash table of pending requets key'd on the clients MAC address
+     */
+    uword *dhcp_pending;
+
+    /**
+     * @brief A lock for the pending request DB.
+     */
+    int lock;
+
+    /**
+     * @brief The source address to use in relayed messaes
+     */
+    ip46_address_t dhcp_src_address;
 
     /**
      * @brief The FIB index (not the external Table-ID) in which the client
      *        is resides.
      */
     u32 rx_fib_index;
-} dhcp_server_t;
+} dhcp_proxy_t;
 
 #define DHCP_N_PROTOS (FIB_PROTOCOL_IP6 + 1)
 
@@ -92,7 +118,7 @@ typedef struct dhcp_server_t_ {
  */
 typedef struct {
   /* Pool of DHCP servers */
-  dhcp_server_t *dhcp_servers[DHCP_N_PROTOS];
+  dhcp_proxy_t *dhcp_servers[DHCP_N_PROTOS];
 
   /* Pool of selected DHCP server. Zero is the default server */
   u32 * dhcp_server_index_by_rx_fib_index[DHCP_N_PROTOS];
@@ -114,12 +140,7 @@ extern dhcp_proxy_main_t dhcp_proxy_main;
 void dhcp_send_details (fib_protocol_t proto,
                         void *opaque,
                         u32 context,
-                        const ip46_address_t *server,
-                        const ip46_address_t *src,
-                        u32 server_fib_id,
-                        u32 rx_fib_id,
-                        u32 vss_fib_id,
-                        u32 vss_oui);
+                        dhcp_proxy_t *proxy);
 
 /**
  * @brief Show (on CLI) a VSS config during a show walk
@@ -157,16 +178,22 @@ int dhcp_proxy_server_add(fib_protocol_t proto,
 
 /**
  * @brief Delete a DHCP proxy config
- * @return 0 is deleted, otherwise an error code
+ * @return 1 if the proxy is deleted, 0 otherwise
  */
 int dhcp_proxy_server_del(fib_protocol_t proto,
-                          u32 rx_fib_index);
+                          u32 rx_fib_index,
+                          ip46_address_t *addr,
+                          u32 server_table_id);
+
+u32
+dhcp_proxy_rx_table_get_table_id (fib_protocol_t proto,
+                                  u32 fib_index);
 
 /**
  * @brief Callback function invoked for each DHCP proxy entry
  *  return 0 to break the walk, non-zero otherwise.
  */
-typedef int (*dhcp_proxy_walk_fn_t)(dhcp_server_t *server,
+typedef int (*dhcp_proxy_walk_fn_t)(dhcp_proxy_t *server,
                                     void *ctx);
 
 /**
@@ -192,6 +219,18 @@ void dhcp_vss_walk(fib_protocol_t proto,
                    void *ctx);
 
 /**
+ * @brief Lock a proxy object to prevent simultaneous access of its
+ *  pending store
+ */
+void dhcp_proxy_lock (dhcp_proxy_t *server);
+
+/**
+ * @brief Lock a proxy object to prevent simultaneous access of its
+ *  pending store
+ */
+void dhcp_proxy_unlock (dhcp_proxy_t *server);
+
+/**
  * @brief Get the VSS data for the FIB index
  */
 static inline dhcp_vss_t *
@@ -215,12 +254,12 @@ dhcp_get_vss_info (dhcp_proxy_main_t *dm,
 /**
  * @brief Get the DHCP proxy server data for the FIB index
  */
-static inline dhcp_server_t *
-dhcp_get_server (dhcp_proxy_main_t *dm,
-                 u32 rx_fib_index,
-                 fib_protocol_t proto)
+static inline dhcp_proxy_t *
+dhcp_get_proxy (dhcp_proxy_main_t *dm,
+                u32 rx_fib_index,
+                fib_protocol_t proto)
 {
-  dhcp_server_t *s = NULL;
+  dhcp_proxy_t *s = NULL;
 
   if (vec_len(dm->dhcp_server_index_by_rx_fib_index[proto]) > rx_fib_index &&
       dm->dhcp_server_index_by_rx_fib_index[proto][rx_fib_index] != ~0)