#include "hash.h"
#include "odp-util.h"
#include "ofp-util.h"
-#include "packets.h"
#include "ovs-thread.h"
+#include "packets.h"
+#include "vlog.h"
+
+VLOG_DEFINE_THIS_MODULE(classifier);
+struct trie_ctx;
static struct cls_subtable *find_subtable(const struct classifier *,
const struct minimask *);
static struct cls_subtable *insert_subtable(struct classifier *,
unsigned int del_priority);
static struct cls_rule *find_match_wc(const struct cls_subtable *,
- const struct flow *,
+ const struct flow *, struct trie_ctx *,
+ unsigned int n_tries,
struct flow_wildcards *);
static struct cls_rule *find_equal(struct cls_subtable *,
const struct miniflow *, uint32_t hash);
static struct cls_rule *next_rule_in_list__(struct cls_rule *);
static struct cls_rule *next_rule_in_list(struct cls_rule *);
+
+static unsigned int minimask_get_prefix_len(const struct minimask *,
+ const struct mf_field *);
+static void trie_init(struct classifier *, int trie_idx,
+ const struct mf_field *);
+static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
+ unsigned int *checkbits);
+
+static void trie_destroy(struct trie_node *);
+static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen);
+static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen);
+static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs,
+ unsigned int nbits);
+static bool mask_prefix_bits_set(const struct flow_wildcards *,
+ uint8_t be32ofs, unsigned int nbits);
+\f
+/* flow/miniflow/minimask/minimatch utilities.
+ * These are only used by the classifier, so place them here to allow
+ * for better optimization. */
+
+static inline uint64_t
+miniflow_get_map_in_range(const struct miniflow *miniflow,
+ uint8_t start, uint8_t end, unsigned int *offset)
+{
+ uint64_t map = miniflow->map;
+ *offset = 0;
+
+ if (start > 0) {
+ uint64_t msk = (UINT64_C(1) << start) - 1; /* 'start' LSBs set */
+ *offset = count_1bits(map & msk);
+ map &= ~msk;
+ }
+ if (end < FLOW_U32S) {
+ uint64_t msk = (UINT64_C(1) << end) - 1; /* 'end' LSBs set */
+ map &= msk;
+ }
+ return map;
+}
+
+/* Returns a hash value for the bits of 'flow' where there are 1-bits in
+ * 'mask', given 'basis'.
+ *
+ * The hash values returned by this function are the same as those returned by
+ * miniflow_hash_in_minimask(), only the form of the arguments differ. */
+static inline uint32_t
+flow_hash_in_minimask(const struct flow *flow, const struct minimask *mask,
+ uint32_t basis)
+{
+ const uint32_t *flow_u32 = (const uint32_t *)flow;
+ const uint32_t *p = mask->masks.values;
+ uint32_t hash;
+ uint64_t map;
+
+ hash = basis;
+ for (map = mask->masks.map; map; map = zero_rightmost_1bit(map)) {
+ hash = mhash_add(hash, flow_u32[raw_ctz(map)] & *p++);
+ }
+
+ return mhash_finish(hash, (p - mask->masks.values) * 4);
+}
+
+/* Returns a hash value for the bits of 'flow' where there are 1-bits in
+ * 'mask', given 'basis'.
+ *
+ * The hash values returned by this function are the same as those returned by
+ * flow_hash_in_minimask(), only the form of the arguments differ. */
+static inline uint32_t
+miniflow_hash_in_minimask(const struct miniflow *flow,
+ const struct minimask *mask, uint32_t basis)
+{
+ const uint32_t *p = mask->masks.values;
+ uint32_t hash = basis;
+ uint32_t flow_u32;
+
+ MINIFLOW_FOR_EACH_IN_MAP(flow_u32, flow, mask->masks.map) {
+ hash = mhash_add(hash, flow_u32 & *p++);
+ }
+
+ return mhash_finish(hash, (p - mask->masks.values) * 4);
+}
+
+/* Returns a hash value for the bits of range [start, end) in 'flow',
+ * where there are 1-bits in 'mask', given 'hash'.
+ *
+ * The hash values returned by this function are the same as those returned by
+ * minimatch_hash_range(), only the form of the arguments differ. */
+static inline uint32_t
+flow_hash_in_minimask_range(const struct flow *flow,
+ const struct minimask *mask,
+ uint8_t start, uint8_t end, uint32_t *basis)
+{
+ const uint32_t *flow_u32 = (const uint32_t *)flow;
+ unsigned int offset;
+ uint64_t map = miniflow_get_map_in_range(&mask->masks, start, end,
+ &offset);
+ const uint32_t *p = mask->masks.values + offset;
+ uint32_t hash = *basis;
+
+ for (; map; map = zero_rightmost_1bit(map)) {
+ hash = mhash_add(hash, flow_u32[raw_ctz(map)] & *p++);
+ }
+
+ *basis = hash; /* Allow continuation from the unfinished value. */
+ return mhash_finish(hash, (p - mask->masks.values) * 4);
+}
+
+/* Fold minimask 'mask''s wildcard mask into 'wc's wildcard mask. */
+static inline void
+flow_wildcards_fold_minimask(struct flow_wildcards *wc,
+ const struct minimask *mask)
+{
+ flow_union_with_miniflow(&wc->masks, &mask->masks);
+}
+
+/* Fold minimask 'mask''s wildcard mask into 'wc's wildcard mask
+ * in range [start, end). */
+static inline void
+flow_wildcards_fold_minimask_range(struct flow_wildcards *wc,
+ const struct minimask *mask,
+ uint8_t start, uint8_t end)
+{
+ uint32_t *dst_u32 = (uint32_t *)&wc->masks;
+ unsigned int offset;
+ uint64_t map = miniflow_get_map_in_range(&mask->masks, start, end,
+ &offset);
+ const uint32_t *p = mask->masks.values + offset;
+
+ for (; map; map = zero_rightmost_1bit(map)) {
+ dst_u32[raw_ctz(map)] |= *p++;
+ }
+}
+
+/* Returns a hash value for 'flow', given 'basis'. */
+static inline uint32_t
+miniflow_hash(const struct miniflow *flow, uint32_t basis)
+{
+ const uint32_t *p = flow->values;
+ uint32_t hash = basis;
+ uint64_t hash_map = 0;
+ uint64_t map;
+
+ for (map = flow->map; map; map = zero_rightmost_1bit(map)) {
+ if (*p) {
+ hash = mhash_add(hash, *p);
+ hash_map |= rightmost_1bit(map);
+ }
+ p++;
+ }
+ hash = mhash_add(hash, hash_map);
+ hash = mhash_add(hash, hash_map >> 32);
+
+ return mhash_finish(hash, p - flow->values);
+}
+
+/* Returns a hash value for 'mask', given 'basis'. */
+static inline uint32_t
+minimask_hash(const struct minimask *mask, uint32_t basis)
+{
+ return miniflow_hash(&mask->masks, basis);
+}
+
+/* Returns a hash value for 'match', given 'basis'. */
+static inline uint32_t
+minimatch_hash(const struct minimatch *match, uint32_t basis)
+{
+ return miniflow_hash(&match->flow, minimask_hash(&match->mask, basis));
+}
+
+/* Returns a hash value for the bits of range [start, end) in 'minimatch',
+ * given 'basis'.
+ *
+ * The hash values returned by this function are the same as those returned by
+ * flow_hash_in_minimask_range(), only the form of the arguments differ. */
+static inline uint32_t
+minimatch_hash_range(const struct minimatch *match, uint8_t start, uint8_t end,
+ uint32_t *basis)
+{
+ unsigned int offset;
+ const uint32_t *p, *q;
+ uint32_t hash = *basis;
+ int n, i;
+
+ n = count_1bits(miniflow_get_map_in_range(&match->mask.masks, start, end,
+ &offset));
+ q = match->mask.masks.values + offset;
+ p = match->flow.values + offset;
+
+ for (i = 0; i < n; i++) {
+ hash = mhash_add(hash, p[i] & q[i]);
+ }
+ *basis = hash; /* Allow continuation from the unfinished value. */
+ return mhash_finish(hash, (offset + n) * 4);
+}
+
\f
/* cls_rule. */
hmap_init(&cls->subtables);
list_init(&cls->subtables_priority);
hmap_init(&cls->partitions);
- ovs_rwlock_init(&cls->rwlock);
+ fat_rwlock_init(&cls->rwlock);
cls->n_flow_segments = 0;
if (flow_segments) {
while (cls->n_flow_segments < CLS_MAX_INDICES
cls->flow_segments[cls->n_flow_segments++] = *flow_segments++;
}
}
+ cls->n_tries = 0;
}
/* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
if (cls) {
struct cls_subtable *partition, *next_partition;
struct cls_subtable *subtable, *next_subtable;
+ int i;
+
+ for (i = 0; i < cls->n_tries; i++) {
+ trie_destroy(cls->tries[i].root);
+ }
HMAP_FOR_EACH_SAFE (subtable, next_subtable, hmap_node,
&cls->subtables) {
free(partition);
}
hmap_destroy(&cls->partitions);
- ovs_rwlock_destroy(&cls->rwlock);
+ fat_rwlock_destroy(&cls->rwlock);
+ }
+}
+
+/* We use uint64_t as a set for the fields below. */
+BUILD_ASSERT_DECL(MFF_N_IDS <= 64);
+
+/* Set the fields for which prefix lookup should be performed. */
+void
+classifier_set_prefix_fields(struct classifier *cls,
+ const enum mf_field_id *trie_fields,
+ unsigned int n_fields)
+{
+ uint64_t fields = 0;
+ int i, trie;
+
+ for (i = 0, trie = 0; i < n_fields && trie < CLS_MAX_TRIES; i++) {
+ const struct mf_field *field = mf_from_id(trie_fields[i]);
+ if (field->flow_be32ofs < 0 || field->n_bits % 32) {
+ /* Incompatible field. This is the only place where we
+ * enforce these requirements, but the rest of the trie code
+ * depends on the flow_be32ofs to be non-negative and the
+ * field length to be a multiple of 32 bits. */
+ continue;
+ }
+
+ if (fields & (UINT64_C(1) << trie_fields[i])) {
+ /* Duplicate field, there is no need to build more than
+ * one index for any one field. */
+ continue;
+ }
+ fields |= UINT64_C(1) << trie_fields[i];
+
+ if (trie >= cls->n_tries || field != cls->tries[trie].field) {
+ trie_init(cls, trie, field);
+ }
+ trie++;
+ }
+
+ /* Destroy the rest. */
+ for (i = trie; i < cls->n_tries; i++) {
+ trie_init(cls, i, NULL);
+ }
+ cls->n_tries = trie;
+}
+
+static void
+trie_init(struct classifier *cls, int trie_idx,
+ const struct mf_field *field)
+{
+ struct cls_trie *trie = &cls->tries[trie_idx];
+ struct cls_subtable *subtable;
+
+ if (trie_idx < cls->n_tries) {
+ trie_destroy(trie->root);
+ }
+ trie->root = NULL;
+ trie->field = field;
+
+ /* Add existing rules to the trie. */
+ LIST_FOR_EACH (subtable, list_node, &cls->subtables_priority) {
+ unsigned int plen;
+
+ plen = field ? minimask_get_prefix_len(&subtable->mask, field) : 0;
+ /* Initialize subtable's prefix length on this field. */
+ subtable->trie_plen[trie_idx] = plen;
+
+ if (plen) {
+ struct cls_rule *head;
+
+ HMAP_FOR_EACH (head, hmap_node, &subtable->rules) {
+ struct cls_rule *rule;
+
+ FOR_EACH_RULE_IN_LIST (rule, head) {
+ trie_insert(trie, rule, plen);
+ }
+ }
+ }
}
}
hash_metadata(ovs_be64 metadata_)
{
uint64_t metadata = (OVS_FORCE uint64_t) metadata_;
- return hash_2words(metadata, metadata >> 32);
+ return hash_uint64(metadata);
}
static struct cls_partition *
old_rule = insert_rule(cls, subtable, rule);
if (!old_rule) {
+ int i;
+
if (minimask_get_metadata_mask(&rule->match.mask) == OVS_BE64_MAX) {
ovs_be64 metadata = miniflow_get_metadata(&rule->match.flow);
rule->partition = create_partition(cls, subtable, metadata);
subtable->n_rules++;
cls->n_rules++;
+
+ for (i = 0; i < cls->n_tries; i++) {
+ if (subtable->trie_plen[i]) {
+ trie_insert(&cls->tries[i], rule, subtable->trie_plen[i]);
+ }
+ }
} else {
rule->partition = old_rule->partition;
}
subtable = find_subtable(cls, &rule->match.mask);
+ for (i = 0; i < cls->n_tries; i++) {
+ if (subtable->trie_plen[i]) {
+ trie_remove(&cls->tries[i], rule, subtable->trie_plen[i]);
+ }
+ }
+
/* Remove rule node from indices. */
for (i = 0; i < subtable->n_indices; i++) {
hindex_remove(&subtable->indices[i], &rule->index_nodes[i]);
} else {
update_subtables_after_removal(cls, subtable, rule->priority);
}
+
cls->n_rules--;
}
+/* Prefix tree context. Valid when 'lookup_done' is true. Can skip all
+ * subtables which have more than 'match_plen' bits in their corresponding
+ * field at offset 'be32ofs'. If skipped, 'maskbits' prefix bits should be
+ * unwildcarded to quarantee datapath flow matches only packets it should. */
+struct trie_ctx {
+ const struct cls_trie *trie;
+ bool lookup_done; /* Status of the lookup. */
+ uint8_t be32ofs; /* U32 offset of the field in question. */
+ unsigned int match_plen; /* Longest prefix than could possibly match. */
+ unsigned int maskbits; /* Prefix length needed to avoid false matches. */
+};
+
+static void
+trie_ctx_init(struct trie_ctx *ctx, const struct cls_trie *trie)
+{
+ ctx->trie = trie;
+ ctx->be32ofs = trie->field->flow_be32ofs;
+ ctx->lookup_done = false;
+}
+
/* Finds and returns the highest-priority rule in 'cls' that matches 'flow'.
* Returns a null pointer if no rules in 'cls' match 'flow'. If multiple rules
* of equal priority match 'flow', returns one arbitrarily.
struct cls_subtable *subtable;
struct cls_rule *best;
tag_type tags;
+ struct trie_ctx trie_ctx[CLS_MAX_TRIES];
+ int i;
/* Determine 'tags' such that, if 'subtable->tag' doesn't intersect them,
* then 'flow' cannot possibly match in 'subtable':
hash_metadata(flow->metadata)));
tags = partition ? partition->tags : TAG_ARBITRARY;
+ /* Initialize trie contexts for match_find_wc(). */
+ for (i = 0; i < cls->n_tries; i++) {
+ trie_ctx_init(&trie_ctx[i], &cls->tries[i]);
+ }
best = NULL;
LIST_FOR_EACH (subtable, list_node, &cls->subtables_priority) {
struct cls_rule *rule;
continue;
}
- rule = find_match_wc(subtable, flow, wc);
+ rule = find_match_wc(subtable, flow, trie_ctx, cls->n_tries, wc);
if (rule) {
best = rule;
LIST_FOR_EACH_CONTINUE (subtable, list_node,
continue;
}
- rule = find_match_wc(subtable, flow, wc);
+ rule = find_match_wc(subtable, flow, trie_ctx, cls->n_tries,
+ wc);
if (rule && rule->priority > best->priority) {
best = rule;
}
break;
}
}
+
return best;
}
+/* Returns true if 'target' satisifies 'match', that is, if each bit for which
+ * 'match' specifies a particular value has the correct value in 'target'. */
+static bool
+minimatch_matches_miniflow(const struct minimatch *match,
+ const struct miniflow *target)
+{
+ const uint32_t *flowp = (const uint32_t *)match->flow.values;
+ const uint32_t *maskp = (const uint32_t *)match->mask.masks.values;
+ uint32_t target_u32;
+
+ MINIFLOW_FOR_EACH_IN_MAP(target_u32, target, match->mask.masks.map) {
+ if ((*flowp++ ^ target_u32) & *maskp++) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static inline struct cls_rule *
+find_match_miniflow(const struct cls_subtable *subtable,
+ const struct miniflow *flow,
+ uint32_t hash)
+{
+ struct cls_rule *rule;
+
+ HMAP_FOR_EACH_WITH_HASH (rule, hmap_node, hash, &subtable->rules) {
+ if (minimatch_matches_miniflow(&rule->match, flow)) {
+ return rule;
+ }
+ }
+
+ return NULL;
+}
+
+/* Finds and returns the highest-priority rule in 'cls' that matches
+ * 'miniflow'. Returns a null pointer if no rules in 'cls' match 'flow'.
+ * If multiple rules of equal priority match 'flow', returns one arbitrarily.
+ *
+ * This function is optimized for the userspace datapath, which only ever has
+ * one priority value for it's flows!
+ */
+struct cls_rule *classifier_lookup_miniflow_first(const struct classifier *cls,
+ const struct miniflow *flow)
+{
+ struct cls_subtable *subtable;
+
+ LIST_FOR_EACH (subtable, list_node, &cls->subtables_priority) {
+ struct cls_rule *rule;
+
+ rule = find_match_miniflow(subtable, flow,
+ miniflow_hash_in_minimask(flow,
+ &subtable->mask,
+ 0));
+ if (rule) {
+ return rule;
+ }
+ }
+
+ return NULL;
+}
+
/* Finds and returns a rule in 'cls' with exactly the same priority and
* matching criteria as 'target'. Returns a null pointer if 'cls' doesn't
* contain an exact match. */
? tag_create_deterministic(hash)
: TAG_ALL);
+ for (i = 0; i < cls->n_tries; i++) {
+ subtable->trie_plen[i] = minimask_get_prefix_len(mask,
+ cls->tries[i].field);
+ }
+
return subtable;
}
}
}
+struct range {
+ uint8_t start;
+ uint8_t end;
+};
+
+/* Return 'true' if can skip rest of the subtable based on the prefix trie
+ * lookup results. */
+static inline bool
+check_tries(struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
+ const unsigned int field_plen[CLS_MAX_TRIES],
+ const struct range ofs, const struct flow *flow,
+ struct flow_wildcards *wc)
+{
+ int j;
+
+ /* Check if we could avoid fully unwildcarding the next level of
+ * fields using the prefix tries. The trie checks are done only as
+ * needed to avoid folding in additional bits to the wildcards mask. */
+ for (j = 0; j < n_tries; j++) {
+ /* Is the trie field relevant for this subtable? */
+ if (field_plen[j]) {
+ struct trie_ctx *ctx = &trie_ctx[j];
+ uint8_t be32ofs = ctx->be32ofs;
+
+ /* Is the trie field within the current range of fields? */
+ if (be32ofs >= ofs.start && be32ofs < ofs.end) {
+ /* On-demand trie lookup. */
+ if (!ctx->lookup_done) {
+ ctx->match_plen = trie_lookup(ctx->trie, flow,
+ &ctx->maskbits);
+ ctx->lookup_done = true;
+ }
+ /* Possible to skip the rest of the subtable if subtable's
+ * prefix on the field is longer than what is known to match
+ * based on the trie lookup. */
+ if (field_plen[j] > ctx->match_plen) {
+ /* RFC: We want the trie lookup to never result in
+ * unwildcarding any bits that would not be unwildcarded
+ * otherwise. Since the trie is shared by the whole
+ * classifier, it is possible that the 'maskbits' contain
+ * bits that are irrelevant for the partition of the
+ * classifier relevant for the current flow. */
+
+ /* Can skip if the field is already unwildcarded. */
+ if (mask_prefix_bits_set(wc, be32ofs, ctx->maskbits)) {
+ return true;
+ }
+ /* Check that the trie result will not unwildcard more bits
+ * than this stage will. */
+ if (ctx->maskbits <= field_plen[j]) {
+ /* Unwildcard the bits and skip the rest. */
+ mask_set_prefix_bits(wc, be32ofs, ctx->maskbits);
+ /* Note: Prerequisite already unwildcarded, as the only
+ * prerequisite of the supported trie lookup fields is
+ * the ethertype, which is currently always
+ * unwildcarded.
+ */
+ return true;
+ }
+ }
+ }
+ }
+ }
+ return false;
+}
+
static inline struct cls_rule *
find_match(const struct cls_subtable *subtable, const struct flow *flow,
uint32_t hash)
static struct cls_rule *
find_match_wc(const struct cls_subtable *subtable, const struct flow *flow,
- struct flow_wildcards * wc)
+ struct trie_ctx trie_ctx[CLS_MAX_TRIES], unsigned int n_tries,
+ struct flow_wildcards *wc)
{
uint32_t basis = 0, hash;
struct cls_rule *rule = NULL;
- uint8_t prev_u32ofs = 0;
int i;
+ struct range ofs;
if (!wc) {
return find_match(subtable, flow,
flow_hash_in_minimask(flow, &subtable->mask, 0));
}
+ ofs.start = 0;
/* Try to finish early by checking fields in segments. */
for (i = 0; i < subtable->n_indices; i++) {
struct hindex_node *inode;
+ ofs.end = subtable->index_ofs[i];
- hash = flow_hash_in_minimask_range(flow, &subtable->mask, prev_u32ofs,
- subtable->index_ofs[i], &basis);
- prev_u32ofs = subtable->index_ofs[i];
+ if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow,
+ wc)) {
+ goto range_out;
+ }
+ hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
+ ofs.end, &basis);
+ ofs.start = ofs.end;
inode = hindex_node_with_hash(&subtable->indices[i], hash);
if (!inode) {
/* No match, can stop immediately, but must fold in the mask
* covered so far. */
- flow_wildcards_fold_minimask_range(wc, &subtable->mask, 0,
- prev_u32ofs);
- return NULL;
+ goto range_out;
}
/* If we have narrowed down to a single rule already, check whether
}
}
}
-
+ ofs.end = FLOW_U32S;
+ /* Trie check for the final range. */
+ if (check_tries(trie_ctx, n_tries, subtable->trie_plen, ofs, flow, wc)) {
+ goto range_out;
+ }
if (!rule) {
/* Multiple potential matches exist, look for one. */
- hash = flow_hash_in_minimask_range(flow, &subtable->mask, prev_u32ofs,
- FLOW_U32S, &basis);
+ hash = flow_hash_in_minimask_range(flow, &subtable->mask, ofs.start,
+ ofs.end, &basis);
rule = find_match(subtable, flow, hash);
} else {
/* We already narrowed the matching candidates down to just 'rule',
rule = NULL;
}
out:
+ /* Must unwildcard all the fields, as they were looked at. */
flow_wildcards_fold_minimask(wc, &subtable->mask);
return rule;
+
+ range_out:
+ /* Must unwildcard the fields looked up so far, if any. */
+ if (ofs.start) {
+ flow_wildcards_fold_minimask_range(wc, &subtable->mask, 0, ofs.start);
+ }
+ return NULL;
}
static struct cls_rule *
struct cls_rule *old = NULL;
int i;
uint32_t basis = 0, hash;
- uint8_t prev_u32ofs = 0;
+ uint8_t prev_be32ofs = 0;
/* Add new node to segment indices. */
for (i = 0; i < subtable->n_indices; i++) {
- hash = minimatch_hash_range(&new->match, prev_u32ofs,
+ hash = minimatch_hash_range(&new->match, prev_be32ofs,
subtable->index_ofs[i], &basis);
hindex_insert(&subtable->indices[i], &new->index_nodes[i], hash);
- prev_u32ofs = subtable->index_ofs[i];
+ prev_be32ofs = subtable->index_ofs[i];
}
- hash = minimatch_hash_range(&new->match, prev_u32ofs, FLOW_U32S, &basis);
+ hash = minimatch_hash_range(&new->match, prev_be32ofs, FLOW_U32S, &basis);
head = find_equal(subtable, &new->match.flow, hash);
if (!head) {
hmap_insert(&subtable->rules, &new->hmap_node, hash);
struct cls_rule *next = next_rule_in_list__(rule);
return next->priority < rule->priority ? next : NULL;
}
+\f
+/* A longest-prefix match tree. */
+struct trie_node {
+ uint32_t prefix; /* Prefix bits for this node, MSB first. */
+ uint8_t nbits; /* Never zero, except for the root node. */
+ unsigned int n_rules; /* Number of rules that have this prefix. */
+ struct trie_node *edges[2]; /* Both NULL if leaf. */
+};
+
+/* Max bits per node. Must fit in struct trie_node's 'prefix'.
+ * Also tested with 16, 8, and 5 to stress the implementation. */
+#define TRIE_PREFIX_BITS 32
+
+/* Return at least 'plen' bits of the 'prefix', starting at bit offset 'ofs'.
+ * Prefixes are in the network byte order, and the offset 0 corresponds to
+ * the most significant bit of the first byte. The offset can be read as
+ * "how many bits to skip from the start of the prefix starting at 'pr'". */
+static uint32_t
+raw_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
+{
+ uint32_t prefix;
+
+ pr += ofs / 32; /* Where to start. */
+ ofs %= 32; /* How many bits to skip at 'pr'. */
+
+ prefix = ntohl(*pr) << ofs; /* Get the first 32 - ofs bits. */
+ if (plen > 32 - ofs) { /* Need more than we have already? */
+ prefix |= ntohl(*++pr) >> (32 - ofs);
+ }
+ /* Return with possible unwanted bits at the end. */
+ return prefix;
+}
+
+/* Return min(TRIE_PREFIX_BITS, plen) bits of the 'prefix', starting at bit
+ * offset 'ofs'. Prefixes are in the network byte order, and the offset 0
+ * corresponds to the most significant bit of the first byte. The offset can
+ * be read as "how many bits to skip from the start of the prefix starting at
+ * 'pr'". */
+static uint32_t
+trie_get_prefix(const ovs_be32 pr[], unsigned int ofs, unsigned int plen)
+{
+ if (!plen) {
+ return 0;
+ }
+ if (plen > TRIE_PREFIX_BITS) {
+ plen = TRIE_PREFIX_BITS; /* Get at most TRIE_PREFIX_BITS. */
+ }
+ /* Return with unwanted bits cleared. */
+ return raw_get_prefix(pr, ofs, plen) & ~0u << (32 - plen);
+}
+
+/* Return the number of equal bits in 'nbits' of 'prefix's MSBs and a 'value'
+ * starting at "MSB 0"-based offset 'ofs'. */
+static unsigned int
+prefix_equal_bits(uint32_t prefix, unsigned int nbits, const ovs_be32 value[],
+ unsigned int ofs)
+{
+ uint64_t diff = prefix ^ raw_get_prefix(value, ofs, nbits);
+ /* Set the bit after the relevant bits to limit the result. */
+ return raw_clz64(diff << 32 | UINT64_C(1) << (63 - nbits));
+}
+
+/* Return the number of equal bits in 'node' prefix and a 'prefix' of length
+ * 'plen', starting at "MSB 0"-based offset 'ofs'. */
+static unsigned int
+trie_prefix_equal_bits(const struct trie_node *node, const ovs_be32 prefix[],
+ unsigned int ofs, unsigned int plen)
+{
+ return prefix_equal_bits(node->prefix, MIN(node->nbits, plen - ofs),
+ prefix, ofs);
+}
+
+/* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' can
+ * be greater than 31. */
+static unsigned int
+be_get_bit_at(const ovs_be32 value[], unsigned int ofs)
+{
+ return (((const uint8_t *)value)[ofs / 8] >> (7 - ofs % 8)) & 1u;
+}
+
+/* Return the bit at ("MSB 0"-based) offset 'ofs' as an int. 'ofs' must
+ * be between 0 and 31, inclusive. */
+static unsigned int
+get_bit_at(const uint32_t prefix, unsigned int ofs)
+{
+ return (prefix >> (31 - ofs)) & 1u;
+}
+
+/* Create new branch. */
+static struct trie_node *
+trie_branch_create(const ovs_be32 *prefix, unsigned int ofs, unsigned int plen,
+ unsigned int n_rules)
+{
+ struct trie_node *node = xmalloc(sizeof *node);
+
+ node->prefix = trie_get_prefix(prefix, ofs, plen);
+
+ if (plen <= TRIE_PREFIX_BITS) {
+ node->nbits = plen;
+ node->edges[0] = NULL;
+ node->edges[1] = NULL;
+ node->n_rules = n_rules;
+ } else { /* Need intermediate nodes. */
+ struct trie_node *subnode = trie_branch_create(prefix,
+ ofs + TRIE_PREFIX_BITS,
+ plen - TRIE_PREFIX_BITS,
+ n_rules);
+ int bit = get_bit_at(subnode->prefix, 0);
+ node->nbits = TRIE_PREFIX_BITS;
+ node->edges[bit] = subnode;
+ node->edges[!bit] = NULL;
+ node->n_rules = 0;
+ }
+ return node;
+}
+
+static void
+trie_node_destroy(struct trie_node *node)
+{
+ free(node);
+}
+
+static void
+trie_destroy(struct trie_node *node)
+{
+ if (node) {
+ trie_destroy(node->edges[0]);
+ trie_destroy(node->edges[1]);
+ free(node);
+ }
+}
+
+static bool
+trie_is_leaf(const struct trie_node *trie)
+{
+ return !trie->edges[0] && !trie->edges[1]; /* No children. */
+}
+
+static void
+mask_set_prefix_bits(struct flow_wildcards *wc, uint8_t be32ofs,
+ unsigned int nbits)
+{
+ ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
+ unsigned int i;
+
+ for (i = 0; i < nbits / 32; i++) {
+ mask[i] = OVS_BE32_MAX;
+ }
+ if (nbits % 32) {
+ mask[i] |= htonl(~0u << (32 - nbits % 32));
+ }
+}
+
+static bool
+mask_prefix_bits_set(const struct flow_wildcards *wc, uint8_t be32ofs,
+ unsigned int nbits)
+{
+ ovs_be32 *mask = &((ovs_be32 *)&wc->masks)[be32ofs];
+ unsigned int i;
+ ovs_be32 zeroes = 0;
+
+ for (i = 0; i < nbits / 32; i++) {
+ zeroes |= ~mask[i];
+ }
+ if (nbits % 32) {
+ zeroes |= ~mask[i] & htonl(~0u << (32 - nbits % 32));
+ }
+
+ return !zeroes; /* All 'nbits' bits set. */
+}
+
+static struct trie_node **
+trie_next_edge(struct trie_node *node, const ovs_be32 value[],
+ unsigned int ofs)
+{
+ return node->edges + be_get_bit_at(value, ofs);
+}
+
+static const struct trie_node *
+trie_next_node(const struct trie_node *node, const ovs_be32 value[],
+ unsigned int ofs)
+{
+ return node->edges[be_get_bit_at(value, ofs)];
+}
+
+/* Return the prefix mask length necessary to find the longest-prefix match for
+ * the '*value' in the prefix tree 'node'.
+ * '*checkbits' is set to the number of bits in the prefix mask necessary to
+ * determine a mismatch, in case there are longer prefixes in the tree below
+ * the one that matched.
+ */
+static unsigned int
+trie_lookup_value(const struct trie_node *node, const ovs_be32 value[],
+ unsigned int *checkbits)
+{
+ unsigned int plen = 0, match_len = 0;
+ const struct trie_node *prev = NULL;
+
+ for (; node; prev = node, node = trie_next_node(node, value, plen)) {
+ unsigned int eqbits;
+ /* Check if this edge can be followed. */
+ eqbits = prefix_equal_bits(node->prefix, node->nbits, value, plen);
+ plen += eqbits;
+ if (eqbits < node->nbits) { /* Mismatch, nothing more to be found. */
+ /* Bit at offset 'plen' differed. */
+ *checkbits = plen + 1; /* Includes the first mismatching bit. */
+ return match_len;
+ }
+ /* Full match, check if rules exist at this prefix length. */
+ if (node->n_rules > 0) {
+ match_len = plen;
+ }
+ }
+ /* Dead end, exclude the other branch if it exists. */
+ *checkbits = !prev || trie_is_leaf(prev) ? plen : plen + 1;
+ return match_len;
+}
+
+static unsigned int
+trie_lookup(const struct cls_trie *trie, const struct flow *flow,
+ unsigned int *checkbits)
+{
+ const struct mf_field *mf = trie->field;
+
+ /* Check that current flow matches the prerequisites for the trie
+ * field. Some match fields are used for multiple purposes, so we
+ * must check that the trie is relevant for this flow. */
+ if (mf_are_prereqs_ok(mf, flow)) {
+ return trie_lookup_value(trie->root,
+ &((ovs_be32 *)flow)[mf->flow_be32ofs],
+ checkbits);
+ }
+ *checkbits = 0; /* Value not used in this case. */
+ return UINT_MAX;
+}
+
+/* Returns the length of a prefix match mask for the field 'mf' in 'minimask'.
+ * Returns the u32 offset to the miniflow data in '*miniflow_index', if
+ * 'miniflow_index' is not NULL. */
+static unsigned int
+minimask_get_prefix_len(const struct minimask *minimask,
+ const struct mf_field *mf)
+{
+ unsigned int nbits = 0, mask_tz = 0; /* Non-zero when end of mask seen. */
+ uint8_t u32_ofs = mf->flow_be32ofs;
+ uint8_t u32_end = u32_ofs + mf->n_bytes / 4;
+
+ for (; u32_ofs < u32_end; ++u32_ofs) {
+ uint32_t mask;
+ mask = ntohl((OVS_FORCE ovs_be32)minimask_get(minimask, u32_ofs));
+
+ /* Validate mask, count the mask length. */
+ if (mask_tz) {
+ if (mask) {
+ return 0; /* No bits allowed after mask ended. */
+ }
+ } else {
+ if (~mask & (~mask + 1)) {
+ return 0; /* Mask not contiguous. */
+ }
+ mask_tz = ctz32(mask);
+ nbits += 32 - mask_tz;
+ }
+ }
+
+ return nbits;
+}
+
+/*
+ * This is called only when mask prefix is known to be CIDR and non-zero.
+ * Relies on the fact that the flow and mask have the same map, and since
+ * the mask is CIDR, the storage for the flow field exists even if it
+ * happened to be zeros.
+ */
+static const ovs_be32 *
+minimatch_get_prefix(const struct minimatch *match, const struct mf_field *mf)
+{
+ return match->flow.values +
+ count_1bits(match->flow.map & ((UINT64_C(1) << mf->flow_be32ofs) - 1));
+}
+
+/* Insert rule in to the prefix tree.
+ * 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
+ * in 'rule'. */
+static void
+trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
+{
+ const ovs_be32 *prefix = minimatch_get_prefix(&rule->match, trie->field);
+ struct trie_node *node;
+ struct trie_node **edge;
+ int ofs = 0;
+
+ /* Walk the tree. */
+ for (edge = &trie->root;
+ (node = *edge) != NULL;
+ edge = trie_next_edge(node, prefix, ofs)) {
+ unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
+ ofs += eqbits;
+ if (eqbits < node->nbits) {
+ /* Mismatch, new node needs to be inserted above. */
+ int old_branch = get_bit_at(node->prefix, eqbits);
+
+ /* New parent node. */
+ *edge = trie_branch_create(prefix, ofs - eqbits, eqbits,
+ ofs == mlen ? 1 : 0);
+
+ /* Adjust old node for its new position in the tree. */
+ node->prefix <<= eqbits;
+ node->nbits -= eqbits;
+ (*edge)->edges[old_branch] = node;
+
+ /* Check if need a new branch for the new rule. */
+ if (ofs < mlen) {
+ (*edge)->edges[!old_branch]
+ = trie_branch_create(prefix, ofs, mlen - ofs, 1);
+ }
+ return;
+ }
+ /* Full match so far. */
+
+ if (ofs == mlen) {
+ /* Full match at the current node, rule needs to be added here. */
+ node->n_rules++;
+ return;
+ }
+ }
+ /* Must insert a new tree branch for the new rule. */
+ *edge = trie_branch_create(prefix, ofs, mlen - ofs, 1);
+}
+
+/* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
+ * in 'rule'. */
+static void
+trie_remove(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
+{
+ const ovs_be32 *prefix = minimatch_get_prefix(&rule->match, trie->field);
+ struct trie_node *node;
+ struct trie_node **edges[sizeof(union mf_value) * 8];
+ int depth = 0, ofs = 0;
+
+ /* Walk the tree. */
+ for (edges[depth] = &trie->root;
+ (node = *edges[depth]) != NULL;
+ edges[++depth] = trie_next_edge(node, prefix, ofs)) {
+ unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
+ if (eqbits < node->nbits) {
+ /* Mismatch, nothing to be removed. This should never happen, as
+ * only rules in the classifier are ever removed. */
+ break; /* Log a warning. */
+ }
+ /* Full match so far. */
+ ofs += eqbits;
+
+ if (ofs == mlen) {
+ /* Full prefix match at the current node, remove rule here. */
+ if (!node->n_rules) {
+ break; /* Log a warning. */
+ }
+ node->n_rules--;
+
+ /* Check if can prune the tree. */
+ while (!node->n_rules && !(node->edges[0] && node->edges[1])) {
+ /* No rules and at most one child node, remove this node. */
+ struct trie_node *next;
+ next = node->edges[0] ? node->edges[0] : node->edges[1];
+
+ if (next) {
+ if (node->nbits + next->nbits > TRIE_PREFIX_BITS) {
+ break; /* Cannot combine. */
+ }
+ /* Combine node with next. */
+ next->prefix = node->prefix | next->prefix >> node->nbits;
+ next->nbits += node->nbits;
+ }
+ trie_node_destroy(node);
+ /* Update the parent's edge. */
+ *edges[depth] = next;
+ if (next || !depth) {
+ /* Branch not pruned or at root, nothing more to do. */
+ break;
+ }
+ node = *edges[--depth];
+ }
+ return;
+ }
+ }
+ /* Cannot go deeper. This should never happen, since only rules
+ * that actually exist in the classifier are ever removed. */
+ VLOG_WARN("Trying to remove non-existing rule from a prefix trie.");
+}
git://git.onelab.eu / sliver-openvswitch.git / blobdiff