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, 72 insertions, 57 deletions

diff --git a/src/vnet/dhcp/dhcp_proxy.c b/src/vnet/dhcp/dhcp_proxy.c
index 8e31c3db..ba7f354e 100644
--- a/src/vnet/dhcp/dhcp_proxy.c
+++ b/src/vnet/dhcp/dhcp_proxy.c
@@ -44,7 +44,7 @@ dhcp_proxy_rx_table_unlock (fib_protocol_t proto,
         mfib_table_unlock(fib_index, proto);
 }
 
-static u32
+ u32
 dhcp_proxy_rx_table_get_table_id (fib_protocol_t proto,
                                   u32 fib_index)
 {
@@ -72,7 +72,7 @@ dhcp_proxy_walk (fib_protocol_t proto,
                  void *ctx)
 {
   dhcp_proxy_main_t * dpm = &dhcp_proxy_main;
-  dhcp_server_t * server;
+  dhcp_proxy_t * server;
   u32 server_index, i;
 
   vec_foreach_index (i, dpm->dhcp_server_index_by_rx_fib_index[proto])
@@ -124,31 +124,68 @@ dhcp_vss_walk (fib_protocol_t proto,
     }
 }
 
+static u32
+dhcp_proxy_server_find (dhcp_proxy_t *proxy,
+                        fib_protocol_t proto,
+                        ip46_address_t *addr,
+                        u32 server_table_id)
+{
+    dhcp_server_t *server;
+    u32 ii, fib_index;
+
+    vec_foreach_index(ii, proxy->dhcp_servers)
+    {
+        server = &proxy->dhcp_servers[ii];
+        fib_index = fib_table_find(proto, server_table_id);
+
+        if (ip46_address_is_equal(&server->dhcp_server,
+                                  addr) &&
+            (server->server_fib_index == fib_index))
+        {
+            return (ii);
+        }
+    }
+    return (~0);
+}
+
 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)
 {
   dhcp_proxy_main_t * dpm = &dhcp_proxy_main;
-  dhcp_server_t * server = 0;
-  int rc = 0;
+  dhcp_proxy_t *proxy = 0;
 
-  server = dhcp_get_server(dpm, rx_fib_index, proto);
+  proxy = dhcp_get_proxy(dpm, rx_fib_index, proto);
 
-  if (NULL == server)
-  {
-      rc = VNET_API_ERROR_NO_SUCH_ENTRY;
-  }
-  else
+  if (NULL != proxy)
   {
-      /* Use the default server again.  */
-      dpm->dhcp_server_index_by_rx_fib_index[proto][rx_fib_index] = ~0;
+      dhcp_server_t *server;
+      u32 index;
 
-      fib_table_unlock (server->server_fib_index, proto);
+      index = dhcp_proxy_server_find(proxy, proto, addr, server_table_id);
 
-      pool_put (dpm->dhcp_servers[proto], server);
+      if (~0 != index)
+      {
+          server = &proxy->dhcp_servers[index];
+          fib_table_unlock (server->server_fib_index, proto);
+
+          vec_del1(proxy->dhcp_servers, index);
+
+          if (0 == vec_len(proxy->dhcp_servers))
+          {
+              /* no servers left, delete the proxy config */
+              dpm->dhcp_server_index_by_rx_fib_index[proto][rx_fib_index] = ~0;
+              vec_free(proxy->dhcp_servers);
+              pool_put (dpm->dhcp_servers[proto], proxy);
+              return (1);
+          }
+      }
   }
 
-  return (rc);
+  /* the proxy still exists */
+  return (0);
 }
 
 int
@@ -159,48 +196,42 @@ dhcp_proxy_server_add (fib_protocol_t proto,
                        u32 server_table_id)
 {
   dhcp_proxy_main_t * dpm = &dhcp_proxy_main;
-  dhcp_server_t * server = 0;
+  dhcp_proxy_t * proxy = 0;
   int new = 0;
 
-  server = dhcp_get_server(dpm, rx_fib_index, proto);
+  proxy = dhcp_get_proxy(dpm, rx_fib_index, proto);
 
-  if (NULL == server)
+  if (NULL == proxy)
   {
       vec_validate_init_empty(dpm->dhcp_server_index_by_rx_fib_index[proto],
                               rx_fib_index,
                               ~0);
 
-      pool_get (dpm->dhcp_servers[proto], server);
-      memset (server, 0, sizeof (*server));
+      pool_get (dpm->dhcp_servers[proto], proxy);
+      memset (proxy, 0, sizeof (*proxy));
       new = 1;
 
       dpm->dhcp_server_index_by_rx_fib_index[proto][rx_fib_index] =
-          server - dpm->dhcp_servers[proto];
+          proxy - dpm->dhcp_servers[proto];
 
-      server->rx_fib_index = rx_fib_index;
-      server->server_fib_index = 
-          fib_table_find_or_create_and_lock(proto, server_table_id);
+      proxy->dhcp_src_address = *src_address;
+      proxy->rx_fib_index = rx_fib_index;
   }
   else
   {
-      /* modify, may need to swap server FIBs */
-      u32 tmp_index;
-
-      tmp_index = fib_table_find(proto, server_table_id);
-
-      if (tmp_index != server->server_fib_index)
+      if (~0 != dhcp_proxy_server_find(proxy, proto, addr, server_table_id))
       {
-          tmp_index = server->server_fib_index;
-
-          /* certainly swapping if the fib doesn't exist */
-          server->server_fib_index = 
-              fib_table_find_or_create_and_lock(proto, server_table_id);
-          fib_table_unlock (tmp_index, proto);
+          return (new);
       }
   }
 
-  server->dhcp_server = *addr;
-  server->dhcp_src_address = *src_address;
+  dhcp_server_t server = {
+      .dhcp_server = *addr,
+      .server_fib_index = fib_table_find_or_create_and_lock(proto,
+                                                            server_table_id),
+  };
+
+  vec_add1(proxy->dhcp_servers, server);
 
   return (new);
 }
@@ -213,31 +244,15 @@ typedef struct dhcp4_proxy_dump_walk_ctx_t_
 } dhcp_proxy_dump_walk_cxt_t;
 
 static int
-dhcp_proxy_dump_walk (dhcp_server_t *server,
+dhcp_proxy_dump_walk (dhcp_proxy_t *proxy,
                       void *arg)
 {
   dhcp_proxy_dump_walk_cxt_t *ctx = arg;
-  fib_table_t *s_fib;
-  u32 rx_table_id;
-  dhcp_vss_t *v;
-
-  v = dhcp_get_vss_info(&dhcp_proxy_main,
-                        server->rx_fib_index,
-                        ctx->proto);
-
-  s_fib = fib_table_get(server->server_fib_index, ctx->proto);
-  rx_table_id = dhcp_proxy_rx_table_get_table_id(server->rx_fib_index,
-                                                 ctx->proto);
 
   dhcp_send_details(ctx->proto,
                     ctx->opaque,
                     ctx->context,
-                    &server->dhcp_server,
-                    &server->dhcp_src_address,
-                    s_fib->ft_table_id,
-                    rx_table_id,
-                    (v ? v->fib_id : 0),
-                    (v ? v->oui : 0));
+                    proxy);
 
   return (1);
 }