REORG: quic: remove quic_cid_trees reference from proto_quic

Previous commit removed access/manipulation to QUIC CID global tree
outside of quic_cid module. This ensures that proper locking is always
performed.

This commit finalizes this cleanup by marking CID global tree as static
only to quic_cid source file. Initialization of this tree is removed
from proto_quic and now performed using dedicated initcalls
quic_alloc_global_cid_tree().

As a side change, complete CID global tree documentation, in particular
to explain CID global tree artificial splitting and ODCID handling.
Overall, the code is now clearer and safer.

diff --git a/include/haproxy/proto_quic.h b/include/haproxy/proto_quic.h
index b420f35459cb8503827dc9cdccb4daa54ff04f67..b6f473c6d20543d62741cdd78b305d3845d09fe4 100644 (file)
--- a/include/haproxy/proto_quic.h
+++ b/include/haproxy/proto_quic.h
@@ -28,12 +28,6 @@
 extern struct protocol proto_quic4;
 extern struct protocol proto_quic6;
 
-struct quic_cid_tree {
-       struct eb_root root;
-       __decl_thread(HA_RWLOCK_T lock);
-};
-
 extern struct quic_dghdlr *quic_dghdlrs;
-extern struct quic_cid_tree *quic_cid_trees;
 
 #endif /* _HAPROXY_PROTO_QUIC_H  */

diff --git a/include/haproxy/quic_cid-t.h b/include/haproxy/quic_cid-t.h
index ccce84497d3046c0280e2983b6ce86673b29198d..f19ce2626c075d53982ff06be4f20ac0b442280e 100644 (file)
--- a/include/haproxy/quic_cid-t.h
+++ b/include/haproxy/quic_cid-t.h
@@ -3,6 +3,12 @@
 
 #include <import/ebtree-t.h>
 #include <haproxy/quic_tp-t.h>
+#include <haproxy/thread.h>
+
+struct quic_cid_tree {
+       struct eb_root root;
+       __decl_thread(HA_RWLOCK_T lock);
+};
 
 /* QUIC connection ID maximum length for version 1. */
 #define QUIC_CID_MAXLEN               20 /* bytes */

diff --git a/include/haproxy/quic_cid.h b/include/haproxy/quic_cid.h
index ac0bde0b15e5db5db9131d8f9975cb6f67e367ed..87f675308d4acc84f3444f40af40c85039b9cd27 100644 (file)
--- a/include/haproxy/quic_cid.h
+++ b/include/haproxy/quic_cid.h
@@ -11,9 +11,12 @@
 #include <haproxy/buf-t.h>
 #include <haproxy/chunk.h>
 #include <haproxy/quic_conn-t.h>
+#include <haproxy/quic_cid-t.h>
 #include <haproxy/quic_rx-t.h>
 #include <haproxy/proto_quic.h>
 
+extern struct quic_cid_tree *quic_cid_trees;
+
 struct quic_connection_id *new_quic_cid(struct eb_root *root,
                                         struct quic_conn *qc,
                                         const struct quic_cid *orig,

diff --git a/src/proto_quic.c b/src/proto_quic.c
index 64fb45c693927730b2f46b3b9eaa7102dd21bf2f..d03123e1e853b5503691c13f198686ef5906dd17 100644 (file)
--- a/src/proto_quic.c
+++ b/src/proto_quic.c
@@ -52,10 +52,6 @@
 /* per-thread quic datagram handlers */
 struct quic_dghdlr *quic_dghdlrs;
 
-/* global CID trees */
-#define QUIC_CID_TREES_CNT 256
-struct quic_cid_tree *quic_cid_trees;
-
 /* Size of the internal buffer of QUIC RX buffer at the fd level */
 #define QUIC_RX_BUFSZ  (1UL << 18)
 
@@ -704,17 +700,6 @@ static int quic_alloc_dghdlrs(void)
                MT_LIST_INIT(&dghdlr->dgrams);
        }
 
-       quic_cid_trees = calloc(QUIC_CID_TREES_CNT, sizeof(*quic_cid_trees));
-       if (!quic_cid_trees) {
-               ha_alert("Failed to allocate global quic CIDs trees.\n");
-               return 0;
-       }
-
-       for (i = 0; i < QUIC_CID_TREES_CNT; ++i) {
-               HA_RWLOCK_INIT(&quic_cid_trees[i].lock);
-               quic_cid_trees[i].root = EB_ROOT_UNIQUE;
-       }
-
        return 1;
 }
 REGISTER_POST_CHECK(quic_alloc_dghdlrs);
@@ -729,8 +714,6 @@ static int quic_deallocate_dghdlrs(void)
                free(quic_dghdlrs);
        }
 
-       ha_free(&quic_cid_trees);
-
        return 1;
 }
 REGISTER_POST_DEINIT(quic_deallocate_dghdlrs);

diff --git a/src/quic_cid.c b/src/quic_cid.c
index 29140d410c0820fcc9024c150ee02e00b496d4db..85caf4a6f83c23f1154f819d4fb5f16b6540cdd3 100644 (file)
--- a/src/quic_cid.c
+++ b/src/quic_cid.c
@@ -1,6 +1,10 @@
+#include <stdlib.h>
+
 #include <import/eb64tree.h>
 #include <import/ebmbtree.h>
 
+#include <haproxy/bug.h>
+#include <haproxy/errors.h>
 #include <haproxy/pool.h>
 #include <haproxy/quic_cid.h>
 #include <haproxy/quic_conn.h>
@@ -9,6 +13,30 @@
 #include <haproxy/trace.h>
 #include <haproxy/xxhash.h>
 
+/* *** QUIC CID handling general principles
+ *
+ * . CID global storage
+ * CIDs generated by haproxy and reuse by the peer as DCID are stored in a
+ * global tree. Tree access must only be done under lock protection.
+ *
+ * . CID global tree splitting
+ * To reduce thread contention, global CID tree is in reality splitted into 256
+ * distinct tree instances. Each CID is assigned to a single tree instance
+ * based on its content. Use quic_cid_tree_idx() to retrieve the expected tree
+ * location for a CID.
+ *
+ * . ODCID handling
+ * ODCID are never stored in global CID tree. This allows to reduce tree size
+ * as clients are expected to switch quickly to a new haproxy assigned CID.
+ * This new CID value is derived by haproxy from the ODCID plus a bunch of
+ * other parameters. If ODCID is reused by the client, first lookup in global
+ * CID tree won't be successful. In this case, derive operation is performed
+ * again before a new tree lookup.
+ */
+
+#define QUIC_CID_TREES_CNT 256
+struct quic_cid_tree *quic_cid_trees;
+
 /* Initialize the stateless reset token attached to <conn_id> connection ID.
  * Returns 1 if succeeded, 0 if not.
  */
@@ -353,3 +381,29 @@ int qc_build_new_connection_id_frm(struct quic_conn *qc,
        TRACE_LEAVE(QUIC_EV_CONN_PRSHPKT, qc);
        return ret;
 }
+
+static int quic_alloc_global_cid_tree(void)
+{
+       int i;
+
+       quic_cid_trees = calloc(QUIC_CID_TREES_CNT, sizeof(*quic_cid_trees));
+       if (!quic_cid_trees) {
+               ha_alert("Failed to allocate global quic CIDs trees.\n");
+               return 0;
+       }
+
+       for (i = 0; i < QUIC_CID_TREES_CNT; ++i) {
+               HA_RWLOCK_INIT(&quic_cid_trees[i].lock);
+               quic_cid_trees[i].root = EB_ROOT_UNIQUE;
+       }
+
+       return 1;
+}
+REGISTER_POST_CHECK(quic_alloc_global_cid_tree);
+
+static int quic_deallocate_global_cid_tree(void)
+{
+       ha_free(&quic_cid_trees);
+       return 1;
+}
+REGISTER_POST_DEINIT(quic_deallocate_global_cid_tree);