/*
- * Copyright (c) 2014 Nicira, Inc.
+ * Copyright (c) 2014, 2015, 2016 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <stddef.h>
#include <stdint.h>
-struct recirc_id_pool;
+#include "cmap.h"
+#include "list.h"
+#include "ofp-actions.h"
+#include "ofproto-dpif-mirror.h"
+#include "ovs-thread.h"
+#include "uuid.h"
+
+struct ofproto_dpif;
+struct rule;
/*
- * Recirculation ID pool.
- * ======================
+ * Freezing and recirculation
+ * ==========================
+ *
+ * Freezing is a technique for halting and checkpointing packet translation in
+ * a way that it can be restarted again later. This file has a couple of data
+ * structures related to freezing in general; their names begin with "frozen".
+ *
+ * Recirculation is the use of freezing to allow a frame to re-enter the
+ * datapath packet processing path to achieve more flexible packet processing,
+ * such as modifying header fields after MPLS POP action and selecting a slave
+ * port for bond ports.
+ *
+ *
+ * Data path and user space interface
+ * -----------------------------------
+ *
+ * Recirculation uses two uint32_t fields, recirc_id and dp_hash, and a RECIRC
+ * action. recirc_id is used to select the next packet processing steps among
+ * multiple instances of recirculation. When a packet initially enters the
+ * datapath it is assigned with recirc_id 0, which indicates no recirculation.
+ * Recirc_ids are managed by the user space, opaque to the datapath.
+ *
+ * On the other hand, dp_hash can only be computed by the datapath, opaque to
+ * the user space, as the datapath is free to choose the hashing algorithm
+ * without informing user space about it. The dp_hash value should be
+ * wildcarded for newly received packets. HASH action specifies whether the
+ * hash is computed, and if computed, how many fields are to be included in the
+ * hash computation. The computed hash value is stored into the dp_hash field
+ * prior to recirculation.
+ *
+ * The RECIRC action sets the recirc_id field and then reprocesses the packet
+ * as if it was received again on the same input port. RECIRC action works
+ * like a function call; actions listed after the RECIRC action will be
+ * executed after recirculation. RECIRC action can be nested, but datapath
+ * implementation limits the number of nested recirculations to prevent
+ * unreasonable nesting depth or infinite loop.
+ *
+ * User space recirculation context
+ * ---------------------------------
+ *
+ * Recirculation is usually hidden from the OpenFlow controllers. Action
+ * translation code deduces when recirculation is necessary and issues a
+ * datapath recirculation action. All OpenFlow actions to be performed after
+ * recirculation are derived from the OpenFlow pipeline and are stored with the
+ * recirculation ID. When the OpenFlow tables are changed in a way affecting
+ * the recirculation flows, new recirculation ID with new metadata and actions
+ * is allocated and the old one is timed out.
*
- * Recirculation ID needs to be unique for each datapath. Recirculation
- * ID pool keeps track recirculation ids.
+ * Recirculation ID pool
+ * ----------------------
*
- * Typically, there is one recirculation ID pool for each backer.
+ * Recirculation ID needs to be unique for all datapaths. Recirculation ID
+ * pool keeps track of recirculation ids and stores OpenFlow pipeline
+ * translation context so that flow processing may continue after
+ * recirculation.
*
- * In theory, Recirculation ID can be any uint32_t value, except 0.
- * The implementation usually limits it to a smaller range to ease
- * debugging.
+ * A Recirculation ID can be any uint32_t value, except for that the value 0 is
+ * reserved for 'no recirculation' case.
*
* Thread-safety
- * =============
+ * --------------
*
* All APIs are thread safe.
- *
*/
-struct recirc_id_pool *recirc_id_pool_create(void);
-void recirc_id_pool_destroy(struct recirc_id_pool *pool);
-uint32_t recirc_id_alloc(struct recirc_id_pool *pool);
-void recirc_id_free(struct recirc_id_pool *pool, uint32_t recirc_id);
+
+/* Metadata for restoring pipeline context after recirculation. Helpers
+ * are inlined below to keep them together with the definition for easier
+ * updates. */
+BUILD_ASSERT_DECL(FLOW_WC_SEQ == 35);
+
+struct frozen_metadata {
+ /* Metadata in struct flow. */
+ const struct flow_tnl *tunnel; /* Encapsulating tunnel parameters. */
+ ovs_be64 metadata; /* OpenFlow Metadata. */
+ uint64_t regs[FLOW_N_XREGS]; /* Registers. */
+ ofp_port_t in_port; /* Incoming port. */
+};
+
+static inline void
+frozen_metadata_from_flow(struct frozen_metadata *md,
+ const struct flow *flow)
+{
+ memset(md, 0, sizeof *md);
+ md->tunnel = &flow->tunnel;
+ md->metadata = flow->metadata;
+ memcpy(md->regs, flow->regs, sizeof md->regs);
+ md->in_port = flow->in_port.ofp_port;
+}
+
+static inline void
+frozen_metadata_to_flow(const struct frozen_metadata *md,
+ struct flow *flow)
+{
+ if (md->tunnel && flow_tnl_dst_is_set(md->tunnel)) {
+ flow->tunnel = *md->tunnel;
+ } else {
+ memset(&flow->tunnel, 0, sizeof flow->tunnel);
+ }
+ flow->metadata = md->metadata;
+ memcpy(flow->regs, md->regs, sizeof flow->regs);
+ flow->in_port.ofp_port = md->in_port;
+}
+
+/* State that flow translation can save, to restore when translation
+ * resumes. */
+struct frozen_state {
+ /* Initial table for processing when thawing. */
+ uint8_t table_id;
+
+ /* Pipeline context for processing when thawing. */
+ struct uuid ofproto_uuid; /* Bridge to resume from. */
+ struct frozen_metadata metadata; /* Flow metadata. */
+ union mf_subvalue *stack; /* Stack if any. */
+ size_t n_stack;
+ mirror_mask_t mirrors; /* Mirrors already output. */
+ bool conntracked; /* Conntrack occurred prior to freeze. */
+
+ /* Actions to be translated when thawing. */
+ struct ofpact *ofpacts;
+ size_t ofpacts_len; /* Size of 'ofpacts', in bytes. */
+ struct ofpact *action_set;
+ size_t action_set_len; /* Size of 'action_set', in bytes. */
+};
+
+/* This maps a recirculation ID to saved state that flow translation can
+ * restore when recirculation occurs. */
+struct recirc_id_node {
+ /* Index data. */
+ struct ovs_list exp_node OVS_GUARDED;
+ struct cmap_node id_node;
+ struct cmap_node metadata_node;
+ uint32_t id;
+ uint32_t hash;
+ struct ovs_refcount refcount;
+
+ /* Saved state.
+ *
+ * This state should not be modified after inserting a node in the pool,
+ * hence the 'const' to emphasize that. */
+ const struct frozen_state state;
+
+ /* Storage for tunnel metadata. */
+ struct flow_tnl state_metadata_tunnel;
+};
+
+void recirc_init(void);
+
+/* This is only used for bonds and will go away when bonds implementation is
+ * updated to use this mechanism instead of internal rules. */
+uint32_t recirc_alloc_id(struct ofproto_dpif *);
+
+uint32_t recirc_alloc_id_ctx(const struct frozen_state *);
+uint32_t recirc_find_id(const struct frozen_state *);
+void recirc_free_id(uint32_t recirc_id);
+void recirc_free_ofproto(struct ofproto_dpif *, const char *ofproto_name);
+
+const struct recirc_id_node *recirc_id_node_find(uint32_t recirc_id);
+
+static inline struct recirc_id_node *
+recirc_id_node_from_state(const struct frozen_state *state)
+{
+ return CONTAINER_OF(state, struct recirc_id_node, state);
+}
+
+static inline bool recirc_id_node_try_ref_rcu(const struct recirc_id_node *n_)
+{
+ struct recirc_id_node *node = CONST_CAST(struct recirc_id_node *, n_);
+
+ return node ? ovs_refcount_try_ref_rcu(&node->refcount) : false;
+}
+
+void recirc_id_node_unref(const struct recirc_id_node *);
+
+void recirc_run(void);
+
+/* Recirculation IDs on which references are held. */
+struct recirc_refs {
+ unsigned n_recircs;
+ union {
+ uint32_t recirc[2]; /* When n_recircs == 1 or 2 */
+ uint32_t *recircs; /* When 'n_recircs' > 2 */
+ };
+};
+
+#define RECIRC_REFS_EMPTY_INITIALIZER ((struct recirc_refs) \
+ { 0, { { 0, 0 } } })
+/* Helpers to abstract the recirculation union away. */
+static inline void
+recirc_refs_init(struct recirc_refs *rr)
+{
+ *rr = RECIRC_REFS_EMPTY_INITIALIZER;
+}
+
+static inline void
+recirc_refs_add(struct recirc_refs *rr, uint32_t id)
+{
+ if (OVS_LIKELY(rr->n_recircs < ARRAY_SIZE(rr->recirc))) {
+ rr->recirc[rr->n_recircs++] = id;
+ } else {
+ if (rr->n_recircs == ARRAY_SIZE(rr->recirc)) {
+ uint32_t *recircs = xmalloc(sizeof rr->recirc + sizeof id);
+
+ memcpy(recircs, rr->recirc, sizeof rr->recirc);
+ rr->recircs = recircs;
+ } else {
+ rr->recircs = xrealloc(rr->recircs,
+ (rr->n_recircs + 1) * sizeof id);
+ }
+ rr->recircs[rr->n_recircs++] = id;
+ }
+}
+
+static inline void
+recirc_refs_swap(struct recirc_refs *a, struct recirc_refs *b)
+{
+ struct recirc_refs tmp;
+
+ tmp = *a;
+ *a = *b;
+ *b = tmp;
+}
+
+static inline void
+recirc_refs_unref(struct recirc_refs *rr)
+{
+ if (OVS_LIKELY(rr->n_recircs <= ARRAY_SIZE(rr->recirc))) {
+ for (int i = 0; i < rr->n_recircs; i++) {
+ recirc_free_id(rr->recirc[i]);
+ }
+ } else {
+ for (int i = 0; i < rr->n_recircs; i++) {
+ recirc_free_id(rr->recircs[i]);
+ }
+ free(rr->recircs);
+ }
+ rr->n_recircs = 0;
+}
+
#endif
projects / cascardo / ovs.git / blobdiff