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/*
* Copyright (c) 2017-2019 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __HICN_HASHTB_H__
#define __HICN_HASHTB_H__
#include <stdint.h>
#include <vppinfra/bihash_8_8.h>
#include <vppinfra/bihash_24_8.h>
#include "params.h"
#include "parser.h"
#include "error.h"
/* Handy abbreviations for success status, and for boolean values */
#ifndef TRUE
#define TRUE 1
#endif
#ifndef FALSE
#define FALSE 0
#endif
/*
* Lookup is finding a hashtable record whose name matches the name being
* looked up. Most of the lookup work is based on the hash value of the two
* names. Note that the intel cache line size is 64 bytes, and some platforms
* load in 2 cache lines together. - first step is to match a record at the
* bucket/slot level (htab has an array of htbucket_t/htbc_elmt, where each
* bucket has 7 slots to hold indices for entries.) Matching at this level
* implies - the hashes of the lookup name and the record map to the same
* bucket - the high 32 bits of the hashes (slot bce_hash_msb32s) match. Read
* cost (on the hash table size, i.e. ignoring reading the name being looked
* up): - First step normally requires 1 cache line load to pull in the
* 64-byte htbucket_t with the 7 element slot table holding the hash_msb32s.
* - In the event (hopefully rare for a hash table with appropriate number of
* buckets) that more than 7 elements hash to the same bucket, lookup may
* well need to look not only at the static htbc_elmt_t but at the chain of
* dynamically allocated htbc_elmt_t's linked to the static htbc_elmt_t,
* where each of these holds slot entries for additional elements. - Before
* reaching that point, it is initially required is to read in the hash table
* record fields (ht_bucket_buf, htnode buf, etc) holding pointers to the
* arrays, but these cache lines are common to all lookups so will likely
* already be in the cache. - second step is to match at the record level
* (htnode/htkb level) once a slot-level match happens. Matching at this
* level implies the following match - the hash values (the full 64 bits vs.
* bucket+32 msb, above) With siphash, two names hashing to the same 64-bit
* value is quite rare. - the name which, on the hash table side, is stored
* as a list of htkb_t (key buffers). [In some cases, the full name is not
* compared, and a match is assumed based on hash value match. Read cost: -
* htnode_t, in one cache line, holds hash value and index for the htkb at
* the head of the key buffer list - each key buffer (htkb_t) is cache line
* aligned/sized, and holds 60 bytes of the name and requires a cache line
* read. Simplification is that a fib lookup requires 3 cache lines: - bucket
* - htnode - single key buffer (for cases where a name comparision is done)
*
* Some hashtables (for which rare false positives are tolerable) store hash
* values but no keys. (In ISM NDN forwarder, this was used for dcm_dpf: data
* cache manager's dataplane filter, where speed was critical and very rare
* false positives would be detected in the full dcm check.) - No key buffers
* are used (or even allocated at hash table creation).
*/
#define HICN_HASH_INVALID_IDX ~0
/*
* for hicn_hashtb_next_node() iterator, this otherwise illegal context value
* indicates first call of iteration. Note: must not be 0, which is a legal
* context value.
*/
#define HICN_HASH_WALK_CTX_INITIAL (~((u64)0))
/*
* Key memory allocation scheme.
*
* The key is the bytestring that a hashtable entry is storing, e.g. a fib
* prefix or packet name. The hash of the name is used not just to pick the
* bucket, but also as a surrogate for the actual key value.
*
* Client calls pass key/name as contiguous memory for lookup/add/delete but
* hashable stores its copy of the key/name as a list of one or more hash_key
* structs. - key memory is managed as a list of keys (cache line
* sized/aligned buffers). - If (keysize < 128) then use key struct's full
* 128 bytes - If not, first key struct is head of a linked list of elements
* where the first bytes are used for the key and the last 4 bytes are the
* index of the next entry (or an end marker). - key memory is generally the
* single largest use of memory in the hash table, especially for PIT, as
* names are bigger than node structs (which is also per name/entry).
*
*/
/* Compute hash node index from node pointer */
#define NODE_IDX_FROM_NODE(p, h) \
(u32)((p) - ((h)->ht_nodes))
#define HICN_HASH_KEY_BYTES 20
typedef struct
{
struct
{
u8 key[HICN_HASH_KEY_BYTES];
} ks; /* Entire key in one block */
} hicn_hash_key_t;
/*
* Ratio of extra key blocks to allocate, in case the embedded ones aren't
* sufficient. This is the fraction of the number of entries allocated.
*/
#define HICN_HASHTB_KEY_RATIO 8
/*
* hash node, used to store a hash table entry; indexed by an entry in a
* bucket. the node contains an embedded key; long keys are stored as chains
* of keys.
*
* The memory block for a node includes space for storing outgoing faces for
* interests, additional memory located off the end of the htnode data structure.
*
*/
/* Size this so that we can offer 64B aligned on 64-bits for storing outgoing
* faces information
*/
#define HICN_HASH_NODE_APP_DATA_SIZE 64
/* How to align in the right way */
typedef struct __attribute__ ((packed)) hicn_hash_node_s
{
/* Bucket id containing the corresponding hash entry. */
u32 bucket_id;
/* Hash entry index in the bucket */
u32 entry_idx;
/* Total size of the key */
u16 hn_keysize;
/* 1 byte of flags for application use */
u8 hn_flags;
u8 _hn_reserved1; /* TBD, to align what follows back to
* 32 */
hicn_hash_key_t hn_key; /* Key value embedded in the node, may chain
* to more key buffers if necessary */
/* 32B + HICN_HASH_NODE_APP_DATA_SIZE */
/* Followed by app-specific data (fib or pit or cs entry, e.g.) */
u8 hn_data[HICN_HASH_NODE_APP_DATA_SIZE];
} hicn_hash_node_t;
#define HICN_HASH_NODE_FLAGS_DEFAULT 0x00
#define HICN_HASH_NODE_CS_FLAGS 0x01
#define HICN_HASH_NODE_OVERFLOW_BUCKET 0x02
/*
* hicn_hash_entry_t Structure holding all or part of a hash value, a node
* index, and other key pieces of info.
*
* - 128 bytes/bucket with 19 bytes/entry gives 6 entries, or 5 entries plus
* next bucket ptr if overflow Changes in this structure will affect
* hicn_hash_bucket_t
*/
typedef struct __attribute__ ((packed)) hicn_hash_entry_s
{
/* MSB of the hash value */
u64 he_msb64;
/* Index of node block */
u32 he_node;
/*
* Lock to prevent hash_node deletion while there are still interest
* or data referring to it
*/
u32 locks;
/* Index of dpo (4B) */
index_t dpo_ctx_id;
/* A few flags, including 'this points to a chain of buckets' */
u8 he_flags;
/*
* Index of the virtual function table corresponding to the dpo_ctx
* strategy
*/
u8 vft_id;
} hicn_hash_entry_t; //size 22B
STATIC_ASSERT (sizeof (index_t) <= 4, "sizeof index_t is greater than 4B");
#define HICN_HASH_ENTRY_FLAGS_DEFAULT 0x00
/* If entry is PIT this flag is 0 */
#define HICN_HASH_ENTRY_FLAG_CS_ENTRY 0x01
/*
* This entry heads a chain of overflow buckets (we expect to see this only
* in the last entry in a bucket.) In this case, the index is to an overflow
* bucket rather than to a single node block.
*/
#define HICN_HASH_ENTRY_FLAG_OVERFLOW 0x04
/* This entry has been marked for deletion */
#define HICN_HASH_ENTRY_FLAG_DELETED 0x08
/* Use fast he_timeout units for expiration, slow if not */
#define HICN_HASH_ENTRY_FLAG_FAST_TIMEOUT 0x10
/*
* hash bucket: Contains an array of entries. Cache line sized/aligned, so no
* room for extra fields unless bucket size is increased to 2 cache lines or
* the entry struct shrinks.
*/
/*
* Overflow bucket ratio as a fraction of the fixed/configured count; a pool
* of hash buckets used if a row in the fixed table overflows.
*/
#define HICN_HASHTB_BUCKET_ENTRIES 5
typedef struct __attribute__ ((packed))
{
hicn_hash_entry_t hb_entries[HICN_HASHTB_BUCKET_ENTRIES];
u64 align1;
u64 align2;
u16 align3;
} hicn_hash_bucket_t;
/* Overall target fill-factor for the hashtable */
#define HICN_HASHTB_FILL_FACTOR 4
#define HICN_HASHTB_MIN_ENTRIES (1 << 4) // includes dummy node 0 entry
#define HICN_HASHTB_MAX_ENTRIES (1 << 24)
#define HICN_HASHTB_MIN_BUCKETS (1 << 10)
/*
* htab_t
*
* Hash table main structure.
*
* Contains - pointers to dynamically allocated arrays of cache-line
* sized/aligned structures (buckets, nodes, keys). Put frequently accessed
* fields in the first cache line.
*/
typedef struct hicn_hashtb_s
{
/* 8B - main array of hash buckets */
hicn_hash_bucket_t *ht_buckets;
/* 8B - just-in-case block of overflow buckets */
hicn_hash_bucket_t *ht_overflow_buckets;
/* 8B - block of nodes associated with entries in buckets */
hicn_hash_node_t *ht_nodes;
/* Flags */
u32 ht_flags;
/* Count of buckets allocated in the main array */
u32 ht_bucket_count;
/* Count of overflow buckets allocated */
u32 ht_overflow_bucket_count;
u32 ht_overflow_buckets_used;
/* Count of nodes allocated */
u32 ht_node_count;
u32 ht_nodes_used;
/* Count of overflow key structs allocated */
u32 ht_key_count;
u32 ht_keys_used;
} hicn_hashtb_t, *hicn_hashtb_h;
/*
* Offset to aligned start of additional data (PIT/CS, FIB) embedded in each
* node.
*/
extern u32 ht_node_data_offset_aligned;
/* Flags for hashtable */
#define HICN_HASHTB_FLAGS_DEFAULT 0x00
/*
* Don't use the last entry in each bucket - only use it for overflow. We use
* this for the FIB, currently, so that we can support in-place FIB changes
* that would be difficult if there were hash entry copies as part of
* overflow handling.
*/
#define HICN_HASHTB_FLAG_USE_SEVEN 0x04
#define HICN_HASHTB_FLAG_KEY_FMT_PFX 0x08
#define HICN_HASHTB_FLAG_KEY_FMT_NAME 0x10
/*
* Max prefix name components we'll support in our incremental hashing;
* currently used only for LPM in the FIB.
*/
#define HICN_HASHTB_MAX_NAME_COMPS HICN_PARAM_FIB_ENTRY_PFX_COMPS_MAX
/*
* APIs and inlines
*/
/* Compute hash node index from node pointer */
static inline u32
hicn_hashtb_node_idx_from_node (hicn_hashtb_h h, hicn_hash_node_t * p)
{
return (p - h->ht_nodes);
}
/* Retrieve a hashtable node by node index */
static inline hicn_hash_node_t *
hicn_hashtb_node_from_idx (hicn_hashtb_h h, u32 idx)
{
return (pool_elt_at_index (h->ht_nodes, idx));
}
/* Allocate a brand-new hashtable */
int
hicn_hashtb_alloc (hicn_hashtb_h * ph, u32 max_elems, size_t app_data_size);
/* Free a hashtable, including its embedded arrays */
int hicn_hashtb_free (hicn_hashtb_h * ph);
/* Hash a bytestring, currently using bihash */
u64 hicn_hashtb_hash_bytestring (const u8 * key, u32 keylen);
always_inline hicn_hash_entry_t *
hicn_hashtb_get_entry (hicn_hashtb_h h, u32 entry_idx, u32 bucket_id,
u8 bucket_overflow)
{
hicn_hash_bucket_t *bucket;
if (bucket_overflow)
bucket = pool_elt_at_index (h->ht_overflow_buckets, bucket_id);
else
bucket = (hicn_hash_bucket_t *) (h->ht_buckets + bucket_id);
return &(bucket->hb_entries[entry_idx]);
}
/* Hash a name, currently using bihash */
always_inline u64
hicn_hashtb_hash_name (const u8 * key, u16 keylen)
{
if (key != NULL && keylen == HICN_V4_NAME_LEN)
{
clib_bihash_kv_8_8_t kv;
kv.key = ((u64 *) key)[0];
return clib_bihash_hash_8_8 (&kv);
}
else if (key != NULL && keylen == HICN_V6_NAME_LEN)
{
clib_bihash_kv_24_8_t kv;
kv.key[0] = ((u64 *) key)[0];
kv.key[1] = ((u64 *) key)[1];
kv.key[2] = ((u32 *) key)[4];
return clib_bihash_hash_24_8 (&kv);
}
else
{
return (-1LL);
}
}
/*
* Prepare a hashtable node for insertion, supplying the key and computed
* hash info. This sets up the node->key relationship, possibly allocating
* overflow key buffers.
*/
void
hicn_hashtb_init_node (hicn_hashtb_h h, hicn_hash_node_t * node,
const u8 * key, u32 keylen);
/*
* Insert a node into the hashtable. We expect the caller has used the init
* api to set the node key and hash info, and populated the extra data area
* (if any) - or done the equivalent work itself.
*/
int
hicn_hashtb_insert (hicn_hashtb_h h, hicn_hash_node_t * node,
hicn_hash_entry_t ** hash_entry, u64 hash,
u32 * node_id,
index_t * dpo_ctx_id, u8 * vft_id, u8 * is_cs,
u8 * hash_entry_id, u32 * bucket_id,
u8 * bucket_is_overflow);
/*
* Basic api to lookup a specific hash+key tuple. This does the entire lookup
* operation, retrieving node structs and comparing keys, so it's not
* optimized for prefetching or high performance.
*
* Returns zero and mails back a node on success, errno otherwise.
*/
int
hicn_hashtb_lookup_node (hicn_hashtb_h h, const u8 * key,
u32 keylen, u64 hashval, u8 is_data,
u32 * node_id, index_t * dpo_ctx_id, u8 * vft_id,
u8 * is_cs, u8 * hash_entry_id, u32 * bucket_id,
u8 * bucket_is_overflow);
/*
* Extended api to lookup a specific hash+key tuple. The implementation
* allows the caller to locate nodes that are marked for deletion; this is
* part of some hashtable applications, such as the FIB.
*
* This does the entire lookup operation, retrieving node structs and comparing
* keys, so it's not optimized for prefetching or high performance.
*
* Returns zero and mails back a node on success, errno otherwise.
*/
int
hicn_hashtb_lookup_node_ex (hicn_hashtb_h h, const u8 * key,
u32 keylen, u64 hashval, u8 is_data,
int include_deleted_p, u32 * node_id,
index_t * dpo_ctx_id, u8 * vft_id, u8 * is_cs,
u8 * hash_entry_id, u32 * bucket_id,
u8 * bucket_is_overflow);
/**
* @brief Compares the key in the node with the given key
*
* This function allows to split the hash verification from the comparison of
* the entire key. Useful to exploit prefertching.
* @result 1 if equals, 0 otherwise
*/
int hicn_node_compare (const u8 * key, u32 keylen, hicn_hash_node_t * node);
/*
* Remove a node from a hashtable using the node itself. The internal data
* structs are cleaned up, but the node struct itself is not: the caller must
* free the node itself.
*/
void hicn_hashtb_remove_node (hicn_hashtb_h h, hicn_hash_node_t * node,
u64 hashval);
/*
* Delete a node from a hashtable using the node itself, and delete/free the
* node. Caller's pointer is cleared on success.
*/
void hicn_hashtb_delete (hicn_hashtb_h h, hicn_hash_node_t ** pnode,
u64 hashval);
/*
* Utility to init a new entry in a hashtable bucket/row. We use this to add
* new a node+hash, and to clear out an entry during removal.
*/
void
hicn_hashtb_init_entry (hicn_hash_entry_t * entry,
u32 nodeidx, u64 hashval, u32 locks);
/*
* Return data area embedded in a hash node struct. We maintain an 'offset'
* value in case the common node body struct doesn't leave the data area
* aligned properly.
*/
static inline void *
hicn_hashtb_node_data (hicn_hash_node_t * node)
{
return ((u8 *) (node) + ht_node_data_offset_aligned);
}
/*
* Use some bits of the low half of the hash to locate a row/bucket in the
* table
*/
static inline u32
hicn_hashtb_bucket_idx (hicn_hashtb_h h, u64 hashval)
{
return ((u32) (hashval & (h->ht_bucket_count - 1)));
}
/*
* Return a hash node struct from the free list, or NULL. Note that the
* returned struct is _not_ cleared/zeroed - init is up to the caller.
*/
static inline hicn_hash_node_t *
hicn_hashtb_alloc_node (hicn_hashtb_h h)
{
hicn_hash_node_t *p = NULL;
if (h->ht_nodes_used < h->ht_node_count)
{
pool_get_aligned (h->ht_nodes, p, 8);
h->ht_nodes_used++;
}
return (p);
}
/*
* Release a hashtable node back to the free list when an entry is cleared
*/
void hicn_hashtb_free_node (hicn_hashtb_h h, hicn_hash_node_t * node);
/*
* Walk a hashtable, iterating through the nodes, keeping context in 'ctx'
* between calls.
*
* Set the context value to HICN_HASH_WALK_CTX_INITIAL to start an iteration.
*/
int
hicn_hashtb_next_node (hicn_hashtb_h h, hicn_hash_node_t ** pnode, u64 * ctx);
int
hicn_hashtb_key_to_str (hicn_hashtb_h h, const hicn_hash_node_t * node,
char *buf, int bufsize, int must_fit);
/*
* single hash full name can pass offset for two hashes calculation in case
* we use CS and PIT in a two steps hashes (prefix + seqno)
*/
always_inline int
hicn_hashtb_fullhash (const u8 * name, u16 namelen, u64 * name_hash)
{
*name_hash = hicn_hashtb_hash_name (name, namelen);
return (*name_hash != (-1LL) ? HICN_ERROR_NONE : HICN_ERROR_HASHTB_INVAL);
}
#endif /* // __HICN_HASHTB_H__ */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables: eval: (c-set-style "gnu") End:
*/
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