session: support local sessions and deprecate redirects

Memfd backed shared memory segments can only be negotiated over sockets.
For such scenarios, the existing redirect mechanism that establishes
cut-through sessions does not work anymore as the two peer application
do not share such a socket.

This patch adds support for local sessions, as opposed to sessions
backed by a transport connection, in a way that is almost transparent to
the two applications by reusing the existing binary api messages.
Moreover, all segment allocations are now entirely done through the
segment manager valloc, so segment overlaps due to independent
allocations previously required for redirects are completely avoided.
The one notable characteristic of local sessions (cut-through from app
perspective) notification messages is that they carry pointers to two
event queues, one for each app peer, instead of one. For
transport-backed sessions one of the queues can be inferred but for
local session they cannot.

Change-Id: Ia443fb63e2d9d8e43490275062a708f039038175
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 24 insertions, 52 deletions

diff --git a/src/vnet/session/session_lookup.c b/src/vnet/session/session_lookup.c
index 77f6f4be78d..9ce0b1a22eb 100644
--- a/src/vnet/session/session_lookup.c
+++ b/src/vnet/session/session_lookup.c
@@ -388,17 +388,18 @@ session_lookup_action_index_is_valid (u32 action_index)
   return 1;
 }
 
-static u32
-session_lookup_action_to_app_index (u32 action_index)
+static u64
+session_lookup_action_to_handle (u32 action_index)
 {
   switch (action_index)
     {
     case SESSION_RULES_TABLE_ACTION_DROP:
-      return APP_DROP_INDEX;
+      return SESSION_DROP_HANDLE;
     case SESSION_RULES_TABLE_ACTION_ALLOW:
     case SESSION_RULES_TABLE_INVALID_INDEX:
-      return APP_INVALID_INDEX;
+      return SESSION_INVALID_HANDLE;
     default:
+      /* application index */
       return action_index;
     }
 }
@@ -420,12 +421,13 @@ session_lookup_action_to_session (u32 action_index, u8 fib_proto,
 				  u8 transport_proto)
 {
   u32 app_index;
-  app_index = session_lookup_action_to_app_index (action_index);
+  app_index = session_lookup_action_to_handle (action_index);
   /* Nothing sophisticated for now, action index is app index */
   return session_lookup_app_listen_session (app_index, fib_proto,
 					    transport_proto);
 }
 
+/** UNUSED */
 stream_session_t *
 session_lookup_rules_table_session4 (session_table_t * st, u8 proto,
 				     ip4_address_t * lcl, u16 lcl_port,
@@ -435,12 +437,13 @@ session_lookup_rules_table_session4 (session_table_t * st, u8 proto,
   u32 action_index, app_index;
   action_index = session_rules_table_lookup4 (srt, lcl, rmt, lcl_port,
 					      rmt_port);
-  app_index = session_lookup_action_to_app_index (action_index);
+  app_index = session_lookup_action_to_handle (action_index);
   /* Nothing sophisticated for now, action index is app index */
   return session_lookup_app_listen_session (app_index, FIB_PROTOCOL_IP4,
 					    proto);
 }
 
+/** UNUSED */
 stream_session_t *
 session_lookup_rules_table_session6 (session_table_t * st, u8 proto,
 				     ip6_address_t * lcl, u16 lcl_port,
@@ -450,7 +453,7 @@ session_lookup_rules_table_session6 (session_table_t * st, u8 proto,
   u32 action_index, app_index;
   action_index = session_rules_table_lookup6 (srt, lcl, rmt, lcl_port,
 					      rmt_port);
-  app_index = session_lookup_action_to_app_index (action_index);
+  app_index = session_lookup_action_to_handle (action_index);
   return session_lookup_app_listen_session (app_index, FIB_PROTOCOL_IP6,
 					    proto);
 }
@@ -463,7 +466,7 @@ session_lookup_rules_table_session6 (session_table_t * st, u8 proto,
  * @param use_rules flag that indicates if the session rules of the table
  * 		    should be used
  * @return invalid handle if nothing is found, the handle of a valid listener
- * 	   or an action_index if a rule is hit
+ * 	   or an action derived handle if a rule is hit
  */
 u64
 session_lookup_endpoint_listener (u32 table_index, session_endpoint_t * sep,
@@ -494,7 +497,7 @@ session_lookup_endpoint_listener (u32 table_index, session_endpoint_t * sep,
 	  ai = session_rules_table_lookup4 (srt, &lcl4, &sep->ip.ip4, 0,
 					    sep->port);
 	  if (session_lookup_action_index_is_valid (ai))
-	    return session_lookup_action_to_app_index (ai);
+	    return session_lookup_action_to_handle (ai);
 	}
     }
   else
@@ -515,7 +518,7 @@ session_lookup_endpoint_listener (u32 table_index, session_endpoint_t * sep,
 	  ai = session_rules_table_lookup6 (srt, &lcl6, &sep->ip.ip6, 0,
 					    sep->port);
 	  if (session_lookup_action_index_is_valid (ai))
-	    return session_lookup_action_to_app_index (ai);
+	    return session_lookup_action_to_handle (ai);
 	}
     }
   return SESSION_INVALID_HANDLE;
@@ -535,9 +538,9 @@ session_lookup_endpoint_listener (u32 table_index, session_endpoint_t * sep,
  *
  * @param table_index table where the lookup should be done
  * @param sep session endpoint to be looked up
- * @return index that can be interpreted as an app index or drop action.
+ * @return session handle that can be interpreted as an adjacency
  */
-u32
+u64
 session_lookup_local_endpoint (u32 table_index, session_endpoint_t * sep)
 {
   session_rules_table_t *srt;
@@ -563,7 +566,7 @@ session_lookup_local_endpoint (u32 table_index, session_endpoint_t * sep)
       ai = session_rules_table_lookup4 (srt, &lcl4, &sep->ip.ip4, 0,
 					sep->port);
       if (session_lookup_action_index_is_valid (ai))
-	return session_lookup_action_to_app_index (ai);
+	return session_lookup_action_to_handle (ai);
 
       /*
        * Check if session endpoint is a listener
@@ -572,7 +575,7 @@ session_lookup_local_endpoint (u32 table_index, session_endpoint_t * sep)
 			   sep->transport_proto);
       rv = clib_bihash_search_inline_16_8 (&st->v4_session_hash, &kv4);
       if (rv == 0)
-	return (u32) kv4.value;
+	return kv4.value;
 
       /*
        * Zero out the ip. Logic is that connect to local ips, say
@@ -581,7 +584,7 @@ session_lookup_local_endpoint (u32 table_index, session_endpoint_t * sep)
       kv4.key[0] = 0;
       rv = clib_bihash_search_inline_16_8 (&st->v4_session_hash, &kv4);
       if (rv == 0)
-	return (u32) kv4.value;
+	return kv4.value;
 
       /*
        * Zero out the port and check if we have proxy
@@ -589,7 +592,7 @@ session_lookup_local_endpoint (u32 table_index, session_endpoint_t * sep)
       kv4.key[1] = 0;
       rv = clib_bihash_search_inline_16_8 (&st->v4_session_hash, &kv4);
       if (rv == 0)
-	return (u32) kv4.value;
+	return kv4.value;
     }
   else
     {
@@ -601,13 +604,13 @@ session_lookup_local_endpoint (u32 table_index, session_endpoint_t * sep)
       ai = session_rules_table_lookup6 (srt, &lcl6, &sep->ip.ip6, 0,
 					sep->port);
       if (session_lookup_action_index_is_valid (ai))
-	return session_lookup_action_to_app_index (ai);
+	return session_lookup_action_to_handle (ai);
 
       make_v6_listener_kv (&kv6, &sep->ip.ip6, sep->port,
 			   sep->transport_proto);
       rv = clib_bihash_search_inline_48_8 (&st->v6_session_hash, &kv6);
       if (rv == 0)
-	return (u32) kv6.value;
+	return kv6.value;
 
       /*
        * Zero out the ip. Same logic as above.
@@ -615,7 +618,7 @@ session_lookup_local_endpoint (u32 table_index, session_endpoint_t * sep)
       kv6.key[0] = kv6.key[1] = 0;
       rv = clib_bihash_search_inline_48_8 (&st->v6_session_hash, &kv6);
       if (rv == 0)
-	return (u32) kv6.value;
+	return kv6.value;
 
       /*
        * Zero out the port. Same logic as above.
@@ -623,9 +626,9 @@ session_lookup_local_endpoint (u32 table_index, session_endpoint_t * sep)
       kv6.key[4] = kv6.key[5] = 0;
       rv = clib_bihash_search_inline_48_8 (&st->v6_session_hash, &kv6);
       if (rv == 0)
-	return (u32) kv6.value;
+	return kv6.value;
     }
-  return APP_INVALID_INDEX;
+  return SESSION_INVALID_HANDLE;
 }
 
 static stream_session_t *
@@ -1234,37 +1237,6 @@ session_lookup_safe6 (u32 fib_index, ip6_address_t * lcl, ip6_address_t * rmt,
   return 0;
 }
 
-u64
-session_lookup_local_listener_make_handle (session_endpoint_t * sep)
-{
-  return ((u64) SESSION_LOCAL_TABLE_PREFIX << 32
-	  | (u32) sep->port << 16 | (u32) sep->transport_proto << 8
-	  | (u32) sep->is_ip4);
-}
-
-u8
-session_lookup_local_is_handle (u64 handle)
-{
-  if (handle >> 32 == SESSION_LOCAL_TABLE_PREFIX)
-    return 1;
-  return 0;
-}
-
-int
-session_lookup_local_listener_parse_handle (u64 handle,
-					    session_endpoint_t * sep)
-{
-  u32 local_table_handle;
-  if (handle >> 32 != SESSION_LOCAL_TABLE_PREFIX)
-    return -1;
-  local_table_handle = handle & 0xFFFFFFFFULL;
-  sep->is_ip4 = local_table_handle & 0xff;
-  local_table_handle >>= 8;
-  sep->transport_proto = local_table_handle & 0xff;
-  sep->port = local_table_handle >> 8;
-  return 0;
-}
-
 clib_error_t *
 vnet_session_rule_add_del (session_rule_add_del_args_t * args)
 {