// SPDX-License-Identifier: GPL-2.0-only /* PIPAPO: PIle PAcket POlicies: set for arbitrary concatenations of ranges * * Copyright (c) 2019-2020 Red Hat GmbH * * Author: Stefano Brivio <sbrivio@redhat.com> */ /** * DOC: Theory of Operation * * * Problem * ------- * * Match packet bytes against entries composed of ranged or non-ranged packet * field specifiers, mapping them to arbitrary references. For example: * * :: * * --- fields ---> * | [net],[port],[net]... => [reference] * entries [net],[port],[net]... => [reference] * | [net],[port],[net]... => [reference] * V ... * * where [net] fields can be IP ranges or netmasks, and [port] fields are port * ranges. Arbitrary packet fields can be matched. * * * Algorithm Overview * ------------------ * * This algorithm is loosely inspired by [Ligatti 2010], and fundamentally * relies on the consideration that every contiguous range in a space of b bits * can be converted into b * 2 netmasks, from Theorem 3 in [Rottenstreich 2010], * as also illustrated in Section 9 of [Kogan 2014]. * * Classification against a number of entries, that require matching given bits * of a packet field, is performed by grouping those bits in sets of arbitrary * size, and classifying packet bits one group at a time. * * Example: * to match the source port (16 bits) of a packet, we can divide those 16 bits * in 4 groups of 4 bits each. Given the entry: * 0000 0001 0101 1001 * and a packet with source port: * 0000 0001 1010 1001 * first and second groups match, but the third doesn't. We conclude that the * packet doesn't match the given entry. * * Translate the set to a sequence of lookup tables, one per field. Each table * has two dimensions: bit groups to be matched for a single packet field, and * all the possible values of said groups (buckets). Input entries are * represented as one or more rules, depending on the number of composing * netmasks for the given field specifier, and a group match is indicated as a * set bit, with number corresponding to the rule index, in all the buckets * whose value matches the entry for a given group. * * Rules are mapped between fields through an array of x, n pairs, with each * item mapping a matched rule to one or more rules. The position of the pair in * the array indicates the matched rule to be mapped to the next field, x * indicates the first rule index in the next field, and n the amount of * next-field rules the current rule maps to. * * The mapping array for the last field maps to the desired references. * * To match, we perform table lookups using the values of grouped packet bits, * and use a sequence of bitwise operations to progressively evaluate rule * matching. * * A stand-alone, reference implementation, also including notes about possible * future optimisations, is available at: * https://pipapo.lameexcu.se/ * * Insertion * --------- * * - For each packet field: * * - divide the b packet bits we want to classify into groups of size t, * obtaining ceil(b / t) groups * * Example: match on destination IP address, with t = 4: 32 bits, 8 groups * of 4 bits each * * - allocate a lookup table with one column ("bucket") for each possible * value of a group, and with one row for each group * * Example: 8 groups, 2^4 buckets: * * :: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * 0 * 1 * 2 * 3 * 4 * 5 * 6 * 7 * * - map the bits we want to classify for the current field, for a given * entry, to a single rule for non-ranged and netmask set items, and to one * or multiple rules for ranges. Ranges are expanded to composing netmasks * by pipapo_expand(). * * Example: 2 entries, 10.0.0.5:1024 and 192.168.1.0-192.168.2.1:2048 * - rule #0: 10.0.0.5 * - rule #1: 192.168.1.0/24 * - rule #2: 192.168.2.0/31 * * - insert references to the rules in the lookup table, selecting buckets * according to bit values of a rule in the given group. This is done by * pipapo_insert(). * * Example: given: * - rule #0: 10.0.0.5 mapping to buckets * < 0 10 0 0 0 0 0 5 > * - rule #1: 192.168.1.0/24 mapping to buckets * < 12 0 10 8 0 1 < 0..15 > < 0..15 > > * - rule #2: 192.168.2.0/31 mapping to buckets * < 12 0 10 8 0 2 0 < 0..1 > > * * these bits are set in the lookup table: * * :: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * 0 0 1,2 * 1 1,2 0 * 2 0 1,2 * 3 0 1,2 * 4 0,1,2 * 5 0 1 2 * 6 0,1,2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 * 7 1,2 1,2 1 1 1 0,1 1 1 1 1 1 1 1 1 1 1 * * - if this is not the last field in the set, fill a mapping array that maps * rules from the lookup table to rules belonging to the same entry in * the next lookup table, done by pipapo_map(). * * Note that as rules map to contiguous ranges of rules, given how netmask * expansion and insertion is performed, &union nft_pipapo_map_bucket stores * this information as pairs of first rule index, rule count. * * Example: 2 entries, 10.0.0.5:1024 and 192.168.1.0-192.168.2.1:2048, * given lookup table #0 for field 0 (see example above): * * :: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * 0 0 1,2 * 1 1,2 0 * 2 0 1,2 * 3 0 1,2 * 4 0,1,2 * 5 0 1 2 * 6 0,1,2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 * 7 1,2 1,2 1 1 1 0,1 1 1 1 1 1 1 1 1 1 1 * * and lookup table #1 for field 1 with: * - rule #0: 1024 mapping to buckets * < 0 0 4 0 > * - rule #1: 2048 mapping to buckets * < 0 0 5 0 > * * :: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * 0 0,1 * 1 0,1 * 2 0 1 * 3 0,1 * * we need to map rules for 10.0.0.5 in lookup table #0 (rule #0) to 1024 * in lookup table #1 (rule #0) and rules for 192.168.1.0-192.168.2.1 * (rules #1, #2) to 2048 in lookup table #2 (rule #1): * * :: * * rule indices in current field: 0 1 2 * map to rules in next field: 0 1 1 * * - if this is the last field in the set, fill a mapping array that maps * rules from the last lookup table to element pointers, also done by * pipapo_map(). * * Note that, in this implementation, we have two elements (start, end) for * each entry. The pointer to the end element is stored in this array, and * the pointer to the start element is linked from it. * * Example: entry 10.0.0.5:1024 has a corresponding &struct nft_pipapo_elem * pointer, 0x66, and element for 192.168.1.0-192.168.2.1:2048 is at 0x42. * From the rules of lookup table #1 as mapped above: * * :: * * rule indices in last field: 0 1 * map to elements: 0x66 0x42 * * * Matching * -------- * * We use a result bitmap, with the size of a single lookup table bucket, to * represent the matching state that applies at every algorithm step. This is * done by pipapo_lookup(). * * - For each packet field: * * - start with an all-ones result bitmap (res_map in pipapo_lookup()) * * - perform a lookup into the table corresponding to the current field, * for each group, and at every group, AND the current result bitmap with * the value from the lookup table bucket * * :: * * Example: 192.168.1.5 < 12 0 10 8 0 1 0 5 >, with lookup table from * insertion examples. * Lookup table buckets are at least 3 bits wide, we'll assume 8 bits for * convenience in this example. Initial result bitmap is 0xff, the steps * below show the value of the result bitmap after each group is processed: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * 0 0 1,2 * result bitmap is now: 0xff & 0x6 [bucket 12] = 0x6 * * 1 1,2 0 * result bitmap is now: 0x6 & 0x6 [bucket 0] = 0x6 * * 2 0 1,2 * result bitmap is now: 0x6 & 0x6 [bucket 10] = 0x6 * * 3 0 1,2 * result bitmap is now: 0x6 & 0x6 [bucket 8] = 0x6 * * 4 0,1,2 * result bitmap is now: 0x6 & 0x7 [bucket 0] = 0x6 * * 5 0 1 2 * result bitmap is now: 0x6 & 0x2 [bucket 1] = 0x2 * * 6 0,1,2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 * result bitmap is now: 0x2 & 0x7 [bucket 0] = 0x2 * * 7 1,2 1,2 1 1 1 0,1 1 1 1 1 1 1 1 1 1 1 * final result bitmap for this field is: 0x2 & 0x3 [bucket 5] = 0x2 * * - at the next field, start with a new, all-zeroes result bitmap. For each * bit set in the previous result bitmap, fill the new result bitmap * (fill_map in pipapo_lookup()) with the rule indices from the * corresponding buckets of the mapping field for this field, done by * pipapo_refill() * * Example: with mapping table from insertion examples, with the current * result bitmap from the previous example, 0x02: * * :: * * rule indices in current field: 0 1 2 * map to rules in next field: 0 1 1 * * the new result bitmap will be 0x02: rule 1 was set, and rule 1 will be * set. * * We can now extend this example to cover the second iteration of the step * above (lookup and AND bitmap): assuming the port field is * 2048 < 0 0 5 0 >, with starting result bitmap 0x2, and lookup table * for "port" field from pre-computation example: * * :: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * 0 0,1 * 1 0,1 * 2 0 1 * 3 0,1 * * operations are: 0x2 & 0x3 [bucket 0] & 0x3 [bucket 0] & 0x2 [bucket 5] * & 0x3 [bucket 0], resulting bitmap is 0x2. * * - if this is the last field in the set, look up the value from the mapping * array corresponding to the final result bitmap * * Example: 0x2 resulting bitmap from 192.168.1.5:2048, mapping array for * last field from insertion example: * * :: * * rule indices in last field: 0 1 * map to elements: 0x66 0x42 * * the matching element is at 0x42. * * * References * ---------- * * [Ligatti 2010] * A Packet-classification Algorithm for Arbitrary Bitmask Rules, with * Automatic Time-space Tradeoffs * Jay Ligatti, Josh Kuhn, and Chris Gage. * Proceedings of the IEEE International Conference on Computer * Communication Networks (ICCCN), August 2010. * https://www.cse.usf.edu/~ligatti/papers/grouper-conf.pdf * * [Rottenstreich 2010] * Worst-Case TCAM Rule Expansion * Ori Rottenstreich and Isaac Keslassy. * 2010 Proceedings IEEE INFOCOM, San Diego, CA, 2010. * http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.212.4592&rep=rep1&type=pdf * * [Kogan 2014] * SAX-PAC (Scalable And eXpressive PAcket Classification) * Kirill Kogan, Sergey Nikolenko, Ori Rottenstreich, William Culhane, * and Patrick Eugster. * Proceedings of the 2014 ACM conference on SIGCOMM, August 2014. * https://www.sigcomm.org/sites/default/files/ccr/papers/2014/August/2619239-2626294.pdf */ #include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/netlink.h> #include <linux/netfilter.h> #include <linux/netfilter/nf_tables.h> #include <net/netfilter/nf_tables_core.h> #include <uapi/linux/netfilter/nf_tables.h> #include <linux/bitmap.h> #include <linux/bitops.h> #include "nft_set_pipapo_avx2.h" #include "nft_set_pipapo.h" /** * pipapo_refill() - For each set bit, set bits from selected mapping table item * @map: Bitmap to be scanned for set bits * @len: Length of bitmap in longs * @rules: Number of rules in field * @dst: Destination bitmap * @mt: Mapping table containing bit set specifiers * @match_only: Find a single bit and return, don't fill * * Iteration over set bits with __builtin_ctzl(): Daniel Lemire, public domain. * * For each bit set in map, select the bucket from mapping table with index * corresponding to the position of the bit set. Use start bit and amount of * bits specified in bucket to fill region in dst. * * Return: -1 on no match, bit position on 'match_only', 0 otherwise. */ int pipapo_refill(unsigned long *map, unsigned int len, unsigned int rules, unsigned long *dst, const union nft_pipapo_map_bucket *mt, bool match_only) { unsigned long bitset; unsigned int k; int ret = -1; for (k = 0; k < len; k++) { bitset = map[k]; while (bitset) { unsigned long t = bitset & -bitset; int r = __builtin_ctzl(bitset); int i = k * BITS_PER_LONG + r; if (unlikely(i >= rules)) { map[k] = 0; return -1; } if (match_only) { bitmap_clear(map, i, 1); return i; } ret = 0; bitmap_set(dst, mt[i].to, mt[i].n); bitset ^= t; } map[k] = 0; } return ret; } /** * pipapo_get_slow() - Get matching element reference given key data * @m: storage containing the set elements * @data: Key data to be matched against existing elements * @genmask: If set, check that element is active in given genmask * @tstamp: timestamp to check for expired elements * * For more details, see DOC: Theory of Operation. * * This is the main lookup function. It matches key data against either * the working match set or the uncommitted copy, depending on what the * caller passed to us. * nft_pipapo_get (lookup from userspace/control plane) and nft_pipapo_lookup * (datapath lookup) pass the active copy. * The insertion path will pass the uncommitted working copy. * * Return: pointer to &struct nft_pipapo_elem on match, NULL otherwise. */ static struct nft_pipapo_elem *pipapo_get_slow(const struct nft_pipapo_match *m, const u8 *data, u8 genmask, u64 tstamp) { unsigned long *res_map, *fill_map, *map; struct nft_pipapo_scratch *scratch; const struct nft_pipapo_field *f; bool map_index; int i; local_bh_disable(); scratch = *raw_cpu_ptr(m->scratch); if (unlikely(!scratch)) goto out; __local_lock_nested_bh(&scratch->bh_lock); map_index = scratch->map_index; map = NFT_PIPAPO_LT_ALIGN(&scratch->__map[0]); res_map = map + (map_index ? m->bsize_max : 0); fill_map = map + (map_index ? 0 : m->bsize_max); pipapo_resmap_init(m, res_map); nft_pipapo_for_each_field(f, i, m) { bool last = i == m->field_count - 1; int b; /* For each bit group: select lookup table bucket depending on * packet bytes value, then AND bucket value */ if (likely(f->bb == 8)) pipapo_and_field_buckets_8bit(f, res_map, data); else pipapo_and_field_buckets_4bit(f, res_map, data); NFT_PIPAPO_GROUP_BITS_ARE_8_OR_4; data += f->groups / NFT_PIPAPO_GROUPS_PER_BYTE(f); /* Now populate the bitmap for the next field, unless this is * the last field, in which case return the matched 'ext' * pointer if any. * * Now res_map contains the matching bitmap, and fill_map is the * bitmap for the next field. */ next_match: b = pipapo_refill(res_map, f->bsize, f->rules, fill_map, f->mt, last); if (b < 0) { scratch->map_index = map_index; __local_unlock_nested_bh(&scratch->bh_lock); local_bh_enable(); return NULL; } if (last) { struct nft_pipapo_elem *e; e = f->mt[b].e; if (unlikely(__nft_set_elem_expired(&e->ext, tstamp) || !nft_set_elem_active(&e->ext, genmask))) goto next_match; /* Last field: we're just returning the key without * filling the initial bitmap for the next field, so the * current inactive bitmap is clean and can be reused as * *next* bitmap (not initial) for the next packet. */ scratch->map_index = map_index; __local_unlock_nested_bh(&scratch->bh_lock); local_bh_enable(); return e; } /* Swap bitmap indices: res_map is the initial bitmap for the * next field, and fill_map is guaranteed to be all-zeroes at * this point. */ map_index = !map_index; swap(res_map, fill_map); data += NFT_PIPAPO_GROUPS_PADDING(f); } __local_unlock_nested_bh(&scratch->bh_lock); out: local_bh_enable(); return NULL; } /** * pipapo_get() - Get matching element reference given key data * @m: Storage containing the set elements * @data: Key data to be matched against existing elements * @genmask: If set, check that element is active in given genmask * @tstamp: Timestamp to check for expired elements * * This is a dispatcher function, either calling out the generic C * implementation or, if available, the AVX2 one. * This helper is only called from the control plane, with either RCU * read lock or transaction mutex held. * * Return: pointer to &struct nft_pipapo_elem on match, NULL otherwise. */ static struct nft_pipapo_elem *pipapo_get(const struct nft_pipapo_match *m, const u8 *data, u8 genmask, u64 tstamp) { struct nft_pipapo_elem *e; local_bh_disable(); #if defined(CONFIG_X86_64) && !defined(CONFIG_UML) if (boot_cpu_has(X86_FEATURE_AVX2) && irq_fpu_usable()) { e = pipapo_get_avx2(m, data, genmask, tstamp); local_bh_enable(); return e; } #endif e = pipapo_get_slow(m, data, genmask, tstamp); local_bh_enable(); return e; } /** * nft_pipapo_lookup() - Dataplane fronted for main lookup function * @net: Network namespace * @set: nftables API set representation * @key: pointer to nft registers containing key data * * This function is called from the data path. It will search for * an element matching the given key in the current active copy. * Unlike other set types, this uses 0 instead of nft_genmask_cur(). * * This is because new (future) elements are not reachable from * priv->match, they get added to priv->clone instead. * When the commit phase flips the generation bitmask, the * 'now old' entries are skipped but without the 'now current' * elements becoming visible. Using nft_genmask_cur() thus creates * inconsistent state: matching old entries get skipped but thew * newly matching entries are unreachable. * * GENMASK_ANY doesn't work for the same reason: old-gen entries get * skipped, new-gen entries are only reachable from priv->clone. * * nft_pipapo_commit swaps ->clone and ->match shortly after the * genbit flip. As ->clone doesn't contain the old entries in the first * place, lookup will only find the now-current ones. * * Return: ntables API extension pointer or NULL if no match. */ const struct nft_set_ext * nft_pipapo_lookup(const struct net *net, const struct nft_set *set, const u32 *key) { struct nft_pipapo *priv = nft_set_priv(set); const struct nft_pipapo_match *m; const struct nft_pipapo_elem *e; m = rcu_dereference(priv->match); e = pipapo_get_slow(m, (const u8 *)key, 0, get_jiffies_64()); return e ? &e->ext : NULL; } /** * nft_pipapo_get() - Get matching element reference given key data * @net: Network namespace * @set: nftables API set representation * @elem: nftables API element representation containing key data * @flags: Unused * * This function is called from the control plane path under * RCU read lock. * * Return: set element private pointer or ERR_PTR(-ENOENT). */ static struct nft_elem_priv * nft_pipapo_get(const struct net *net, const struct nft_set *set, const struct nft_set_elem *elem, unsigned int flags) { struct nft_pipapo *priv = nft_set_priv(set); struct nft_pipapo_match *m = rcu_dereference(priv->match); struct nft_pipapo_elem *e; e = pipapo_get(m, (const u8 *)elem->key.val.data, nft_genmask_cur(net), get_jiffies_64()); if (!e) return ERR_PTR(-ENOENT); return &e->priv; } /** * pipapo_realloc_mt() - Reallocate mapping table if needed upon resize * @f: Field containing mapping table * @old_rules: Amount of existing mapped rules * @rules: Amount of new rules to map * * Return: 0 on success, negative error code on failure. */ static int pipapo_realloc_mt(struct nft_pipapo_field *f, unsigned int old_rules, unsigned int rules) { union nft_pipapo_map_bucket *new_mt = NULL, *old_mt = f->mt; const unsigned int extra = PAGE_SIZE / sizeof(*new_mt); unsigned int rules_alloc = rules; might_sleep(); if (unlikely(rules == 0)) goto out_free; /* growing and enough space left, no action needed */ if (rules > old_rules && f->rules_alloc > rules) return 0; /* downsize and extra slack has not grown too large */ if (rules < old_rules) { unsigned int remove = f->rules_alloc - rules; if (remove < (2u * extra)) return 0; } /* If set needs more than one page of memory for rules then * allocate another extra page to avoid frequent reallocation. */ if (rules > extra && check_add_overflow(rules, extra, &rules_alloc)) return -EOVERFLOW; if (rules_alloc > (INT_MAX / sizeof(*new_mt))) return -ENOMEM; new_mt = kvmalloc_objs(*new_mt, rules_alloc, GFP_KERNEL_ACCOUNT); if (!new_mt) return -ENOMEM; if (old_mt) memcpy(new_mt, old_mt, min(old_rules, rules) * sizeof(*new_mt)); if (rules > old_rules) { memset(new_mt + old_rules, 0, (rules - old_rules) * sizeof(*new_mt)); } out_free: f->rules_alloc = rules_alloc; f->mt = new_mt; kvfree(old_mt); return 0; } /** * lt_calculate_size() - Get storage size for lookup table with overflow check * @groups: Amount of bit groups * @bb: Number of bits grouped together in lookup table buckets * @bsize: Size of each bucket in lookup table, in longs * * Return: allocation size including alignment overhead, negative on overflow */ static ssize_t lt_calculate_size(unsigned int groups, unsigned int bb, unsigned int bsize) { ssize_t ret = groups * NFT_PIPAPO_BUCKETS(bb) * sizeof(long); if (check_mul_overflow(ret, bsize, &ret)) return -1; if (check_add_overflow(ret, NFT_PIPAPO_ALIGN_HEADROOM, &ret)) return -1; if (ret > INT_MAX) return -1; return ret; } /** * pipapo_resize() - Resize lookup or mapping table, or both * @f: Field containing lookup and mapping tables * @old_rules: Previous amount of rules in field * @rules: New amount of rules * * Increase, decrease or maintain tables size depending on new amount of rules, * and copy data over. In case the new size is smaller, throw away data for * highest-numbered rules. * * Return: 0 on success, -ENOMEM on allocation failure. */ static int pipapo_resize(struct nft_pipapo_field *f, unsigned int old_rules, unsigned int rules) { long *new_lt = NULL, *new_p, *old_lt = f->lt, *old_p; unsigned int new_bucket_size, copy; int group, bucket, err; ssize_t lt_size; if (rules >= NFT_PIPAPO_RULE0_MAX) return -ENOSPC; new_bucket_size = DIV_ROUND_UP(rules, BITS_PER_LONG); #ifdef NFT_PIPAPO_ALIGN new_bucket_size = roundup(new_bucket_size, NFT_PIPAPO_ALIGN / sizeof(*new_lt)); #endif if (new_bucket_size == f->bsize) goto mt; if (new_bucket_size > f->bsize) copy = f->bsize; else copy = new_bucket_size; lt_size = lt_calculate_size(f->groups, f->bb, new_bucket_size); if (lt_size < 0) return -ENOMEM; new_lt = kvzalloc(lt_size, GFP_KERNEL_ACCOUNT); if (!new_lt) return -ENOMEM; new_p = NFT_PIPAPO_LT_ALIGN(new_lt); old_p = NFT_PIPAPO_LT_ALIGN(old_lt); for (group = 0; group < f->groups; group++) { for (bucket = 0; bucket < NFT_PIPAPO_BUCKETS(f->bb); bucket++) { memcpy(new_p, old_p, copy * sizeof(*new_p)); new_p += copy; old_p += copy; if (new_bucket_size > f->bsize) new_p += new_bucket_size - f->bsize; else old_p += f->bsize - new_bucket_size; } } mt: err = pipapo_realloc_mt(f, old_rules, rules); if (err) { kvfree(new_lt); return err; } if (new_lt) { f->bsize = new_bucket_size; f->lt = new_lt; kvfree(old_lt); } return 0; } /** * pipapo_bucket_set() - Set rule bit in bucket given group and group value * @f: Field containing lookup table * @rule: Rule index * @group: Group index * @v: Value of bit group */ static void pipapo_bucket_set(struct nft_pipapo_field *f, int rule, int group, int v) { unsigned long *pos; pos = NFT_PIPAPO_LT_ALIGN(f->lt); pos += f->bsize * NFT_PIPAPO_BUCKETS(f->bb) * group; pos += f->bsize * v; __set_bit(rule, pos); } /** * pipapo_lt_4b_to_8b() - Switch lookup table group width from 4 bits to 8 bits * @old_groups: Number of current groups * @bsize: Size of one bucket, in longs * @old_lt: Pointer to the current lookup table * @new_lt: Pointer to the new, pre-allocated lookup table * * Each bucket with index b in the new lookup table, belonging to group g, is * filled with the bit intersection between: * - bucket with index given by the upper 4 bits of b, from group g, and * - bucket with index given by the lower 4 bits of b, from group g + 1 * * That is, given buckets from the new lookup table N(x, y) and the old lookup * table O(x, y), with x bucket index, and y group index: * * N(b, g) := O(b / 16, g) & O(b % 16, g + 1) * * This ensures equivalence of the matching results on lookup. Two examples in * pictures: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 ... 254 255 * 0 ^ * 1 | ^ * ... ( & ) | * / \ | * / \ .-( & )-. * / bucket \ | | * group 0 / 1 2 3 \ 4 5 6 7 8 9 10 11 12 13 |14 15 | * 0 / \ | | * 1 \ | | * 2 | --' * 3 '- * ... */ static void pipapo_lt_4b_to_8b(int old_groups, int bsize, unsigned long *old_lt, unsigned long *new_lt) { int g, b, i; for (g = 0; g < old_groups / 2; g++) { int src_g0 = g * 2, src_g1 = g * 2 + 1; for (b = 0; b < NFT_PIPAPO_BUCKETS(8); b++) { int src_b0 = b / NFT_PIPAPO_BUCKETS(4); int src_b1 = b % NFT_PIPAPO_BUCKETS(4); int src_i0 = src_g0 * NFT_PIPAPO_BUCKETS(4) + src_b0; int src_i1 = src_g1 * NFT_PIPAPO_BUCKETS(4) + src_b1; for (i = 0; i < bsize; i++) { *new_lt = old_lt[src_i0 * bsize + i] & old_lt[src_i1 * bsize + i]; new_lt++; } } } } /** * pipapo_lt_8b_to_4b() - Switch lookup table group width from 8 bits to 4 bits * @old_groups: Number of current groups * @bsize: Size of one bucket, in longs * @old_lt: Pointer to the current lookup table * @new_lt: Pointer to the new, pre-allocated lookup table * * Each bucket with index b in the new lookup table, belonging to group g, is * filled with the bit union of: * - all the buckets with index such that the upper four bits of the lower byte * equal b, from group g, with g odd * - all the buckets with index such that the lower four bits equal b, from * group g, with g even * * That is, given buckets from the new lookup table N(x, y) and the old lookup * table O(x, y), with x bucket index, and y group index: * * - with g odd: N(b, g) := U(O(x, g) for each x : x = (b & 0xf0) >> 4) * - with g even: N(b, g) := U(O(x, g) for each x : x = b & 0x0f) * * where U() denotes the arbitrary union operation (binary OR of n terms). This * ensures equivalence of the matching results on lookup. */ static void pipapo_lt_8b_to_4b(int old_groups, int bsize, unsigned long *old_lt, unsigned long *new_lt) { int g, b, bsrc, i; memset(new_lt, 0, old_groups * 2 * NFT_PIPAPO_BUCKETS(4) * bsize * sizeof(unsigned long)); for (g = 0; g < old_groups * 2; g += 2) { int src_g = g / 2; for (b = 0; b < NFT_PIPAPO_BUCKETS(4); b++) { for (bsrc = NFT_PIPAPO_BUCKETS(8) * src_g; bsrc < NFT_PIPAPO_BUCKETS(8) * (src_g + 1); bsrc++) { if (((bsrc & 0xf0) >> 4) != b) continue; for (i = 0; i < bsize; i++) new_lt[i] |= old_lt[bsrc * bsize + i]; } new_lt += bsize; } for (b = 0; b < NFT_PIPAPO_BUCKETS(4); b++) { for (bsrc = NFT_PIPAPO_BUCKETS(8) * src_g; bsrc < NFT_PIPAPO_BUCKETS(8) * (src_g + 1); bsrc++) { if ((bsrc & 0x0f) != b) continue; for (i = 0; i < bsize; i++) new_lt[i] |= old_lt[bsrc * bsize + i]; } new_lt += bsize; } } } /** * pipapo_lt_bits_adjust() - Adjust group size for lookup table if needed * @f: Field containing lookup table */ static void pipapo_lt_bits_adjust(struct nft_pipapo_field *f) { unsigned int groups, bb; unsigned long *new_lt; ssize_t lt_size; lt_size = f->groups * NFT_PIPAPO_BUCKETS(f->bb) * f->bsize * sizeof(*f->lt); if (f->bb == NFT_PIPAPO_GROUP_BITS_SMALL_SET && lt_size > NFT_PIPAPO_LT_SIZE_HIGH) { groups = f->groups * 2; bb = NFT_PIPAPO_GROUP_BITS_LARGE_SET; lt_size = lt_calculate_size(groups, bb, f->bsize); if (lt_size < 0) return; } else if (f->bb == NFT_PIPAPO_GROUP_BITS_LARGE_SET && lt_size < NFT_PIPAPO_LT_SIZE_LOW) { groups = f->groups / 2; bb = NFT_PIPAPO_GROUP_BITS_SMALL_SET; lt_size = lt_calculate_size(groups, bb, f->bsize); if (lt_size < 0) return; /* Don't increase group width if the resulting lookup table size * would exceed the upper size threshold for a "small" set. */ if (lt_size > NFT_PIPAPO_LT_SIZE_HIGH) return; } else { return; } new_lt = kvzalloc(lt_size, GFP_KERNEL_ACCOUNT); if (!new_lt) return; NFT_PIPAPO_GROUP_BITS_ARE_8_OR_4; if (f->bb == 4 && bb == 8) { pipapo_lt_4b_to_8b(f->groups, f->bsize, NFT_PIPAPO_LT_ALIGN(f->lt), NFT_PIPAPO_LT_ALIGN(new_lt)); } else if (f->bb == 8 && bb == 4) { pipapo_lt_8b_to_4b(f->groups, f->bsize, NFT_PIPAPO_LT_ALIGN(f->lt), NFT_PIPAPO_LT_ALIGN(new_lt)); } else { BUG(); } f->groups = groups; f->bb = bb; kvfree(f->lt); f->lt = new_lt; } /** * pipapo_insert() - Insert new rule in field given input key and mask length * @f: Field containing lookup table * @k: Input key for classification, without nftables padding * @mask_bits: Length of mask; matches field length for non-ranged entry * * Insert a new rule reference in lookup buckets corresponding to k and * mask_bits. * * Return: 1 on success (one rule inserted), negative error code on failure. */ static int pipapo_insert(struct nft_pipapo_field *f, const uint8_t *k, int mask_bits) { unsigned int rule = f->rules, group, ret, bit_offset = 0; ret = pipapo_resize(f, f->rules, f->rules + 1); if (ret) return ret; f->rules++; for (group = 0; group < f->groups; group++) { int i, v; u8 mask; v = k[group / (BITS_PER_BYTE / f->bb)]; v &= GENMASK(BITS_PER_BYTE - bit_offset - 1, 0); v >>= (BITS_PER_BYTE - bit_offset) - f->bb; bit_offset += f->bb; bit_offset %= BITS_PER_BYTE; if (mask_bits >= (group + 1) * f->bb) { /* Not masked */ pipapo_bucket_set(f, rule, group, v); } else if (mask_bits <= group * f->bb) { /* Completely masked */ for (i = 0; i < NFT_PIPAPO_BUCKETS(f->bb); i++) pipapo_bucket_set(f, rule, group, i); } else { /* The mask limit falls on this group */ mask = GENMASK(f->bb - 1, 0); mask >>= mask_bits - group * f->bb; for (i = 0; i < NFT_PIPAPO_BUCKETS(f->bb); i++) { if ((i & ~mask) == (v & ~mask)) pipapo_bucket_set(f, rule, group, i); } } } pipapo_lt_bits_adjust(f); return 1; } /** * pipapo_step_diff() - Check if setting @step bit in netmask would change it * @base: Mask we are expanding * @step: Step bit for given expansion step * @len: Total length of mask space (set and unset bits), bytes * * Convenience function for mask expansion. * * Return: true if step bit changes mask (i.e. isn't set), false otherwise. */ static bool pipapo_step_diff(u8 *base, int step, int len) { /* Network order, byte-addressed */ #ifdef __BIG_ENDIAN__ return !(BIT(step % BITS_PER_BYTE) & base[step / BITS_PER_BYTE]); #else return !(BIT(step % BITS_PER_BYTE) & base[len - 1 - step / BITS_PER_BYTE]); #endif } /** * pipapo_step_after_end() - Check if mask exceeds range end with given step * @base: Mask we are expanding * @end: End of range * @step: Step bit for given expansion step, highest bit to be set * @len: Total length of mask space (set and unset bits), bytes * * Convenience function for mask expansion. * * Return: true if mask exceeds range setting step bits, false otherwise. */ static bool pipapo_step_after_end(const u8 *base, const u8 *end, int step, int len) { u8 tmp[NFT_PIPAPO_MAX_BYTES]; int i; memcpy(tmp, base, len); /* Network order, byte-addressed */ for (i = 0; i <= step; i++) #ifdef __BIG_ENDIAN__ tmp[i / BITS_PER_BYTE] |= BIT(i % BITS_PER_BYTE); #else tmp[len - 1 - i / BITS_PER_BYTE] |= BIT(i % BITS_PER_BYTE); #endif return memcmp(tmp, end, len) > 0; } /** * pipapo_base_sum() - Sum step bit to given len-sized netmask base with carry * @base: Netmask base * @step: Step bit to sum * @len: Netmask length, bytes */ static void pipapo_base_sum(u8 *base, int step, int len) { bool carry = false; int i; /* Network order, byte-addressed */ #ifdef __BIG_ENDIAN__ for (i = step / BITS_PER_BYTE; i < len; i++) { #else for (i = len - 1 - step / BITS_PER_BYTE; i >= 0; i--) { #endif if (carry) base[i]++; else base[i] += 1 << (step % BITS_PER_BYTE); if (base[i]) break; carry = true; } } /** * pipapo_expand() - Expand to composing netmasks, insert into lookup table * @f: Field containing lookup table * @start: Start of range * @end: End of range * @len: Length of value in bits * * Expand range to composing netmasks and insert corresponding rule references * in lookup buckets. * * Return: number of inserted rules on success, negative error code on failure. */ static int pipapo_expand(struct nft_pipapo_field *f, const u8 *start, const u8 *end, int len) { int step, masks = 0, bytes = DIV_ROUND_UP(len, BITS_PER_BYTE); u8 base[NFT_PIPAPO_MAX_BYTES]; memcpy(base, start, bytes); while (memcmp(base, end, bytes) <= 0) { int err; step = 0; while (pipapo_step_diff(base, step, bytes)) { if (pipapo_step_after_end(base, end, step, bytes)) break; step++; if (step >= len) { if (!masks) { err = pipapo_insert(f, base, 0); if (err < 0) return err; masks = 1; } goto out; } } err = pipapo_insert(f, base, len - step); if (err < 0) return err; masks++; pipapo_base_sum(base, step, bytes); } out: return masks; } /** * pipapo_map() - Insert rules in mapping tables, mapping them between fields * @m: Matching data, including mapping table * @map: Table of rule maps: array of first rule and amount of rules * in next field a given rule maps to, for each field * @e: For last field, nft_set_ext pointer matching rules map to */ static void pipapo_map(struct nft_pipapo_match *m, union nft_pipapo_map_bucket map[NFT_PIPAPO_MAX_FIELDS], struct nft_pipapo_elem *e) { struct nft_pipapo_field *f; int i, j; for (i = 0, f = m->f; i < m->field_count - 1; i++, f++) { for (j = 0; j < map[i].n; j++) { f->mt[map[i].to + j].to = map[i + 1].to; f->mt[map[i].to + j].n = map[i + 1].n; } } /* Last field: map to ext instead of mapping to next field */ for (j = 0; j < map[i].n; j++) f->mt[map[i].to + j].e = e; } /** * pipapo_free_scratch() - Free per-CPU map at original address * @m: Matching data * @cpu: CPU number */ static void pipapo_free_scratch(const struct nft_pipapo_match *m, unsigned int cpu) { struct nft_pipapo_scratch *s; s = *per_cpu_ptr(m->scratch, cpu); kvfree(s); } /** * pipapo_realloc_scratch() - Reallocate scratch maps for partial match results * @clone: Copy of matching data with pending insertions and deletions * @bsize_max: Maximum bucket size, scratch maps cover two buckets * * Return: 0 on success, -ENOMEM on failure. */ static int pipapo_realloc_scratch(struct nft_pipapo_match *clone, unsigned long bsize_max) { int i; for_each_possible_cpu(i) { struct nft_pipapo_scratch *scratch; scratch = kvzalloc_node(struct_size(scratch, __map, bsize_max * 2) + NFT_PIPAPO_ALIGN_HEADROOM, GFP_KERNEL_ACCOUNT, cpu_to_node(i)); if (!scratch) { /* On failure, there's no need to undo previous * allocations: this means that some scratch maps have * a bigger allocated size now (this is only called on * insertion), but the extra space won't be used by any * CPU as new elements are not inserted and m->bsize_max * is not updated. */ return -ENOMEM; } pipapo_free_scratch(clone, i); local_lock_init(&scratch->bh_lock); *per_cpu_ptr(clone->scratch, i) = scratch; } return 0; } static bool nft_pipapo_transaction_mutex_held(const struct nft_set *set) { #ifdef CONFIG_PROVE_LOCKING const struct net *net = read_pnet(&set->net); return lockdep_is_held(&nft_pernet(net)->commit_mutex); #else return true; #endif } static struct nft_pipapo_match *pipapo_clone(struct nft_pipapo_match *old); /** * pipapo_maybe_clone() - Build clone for pending data changes, if not existing * @set: nftables API set representation * * Return: newly created or existing clone, if any. NULL on allocation failure */ static struct nft_pipapo_match *pipapo_maybe_clone(const struct nft_set *set) { struct nft_pipapo *priv = nft_set_priv(set); struct nft_pipapo_match *m; if (priv->clone) return priv->clone; m = rcu_dereference_protected(priv->match, nft_pipapo_transaction_mutex_held(set)); priv->clone = pipapo_clone(m); return priv->clone; } /** * nft_pipapo_insert() - Validate and insert ranged elements * @net: Network namespace * @set: nftables API set representation * @elem: nftables API element representation containing key data * @elem_priv: Filled with pointer to &struct nft_set_ext in inserted element * * Return: 0 on success, error pointer on failure. */ static int nft_pipapo_insert(const struct net *net, const struct nft_set *set, const struct nft_set_elem *elem, struct nft_elem_priv **elem_priv) { const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv); union nft_pipapo_map_bucket rulemap[NFT_PIPAPO_MAX_FIELDS]; const u8 *start = (const u8 *)elem->key.val.data, *end; struct nft_pipapo_match *m = pipapo_maybe_clone(set); u8 genmask = nft_genmask_next(net); struct nft_pipapo_elem *e, *dup; u64 tstamp = nft_net_tstamp(net); struct nft_pipapo_field *f; const u8 *start_p, *end_p; int i, bsize_max, err = 0; if (!m) return -ENOMEM; if (nft_set_ext_exists(ext, NFT_SET_EXT_KEY_END)) end = (const u8 *)nft_set_ext_key_end(ext)->data; else end = start; dup = pipapo_get(m, start, genmask, tstamp); if (dup) { /* Check if we already have the same exact entry */ const struct nft_data *dup_key, *dup_end; dup_key = nft_set_ext_key(&dup->ext); if (nft_set_ext_exists(&dup->ext, NFT_SET_EXT_KEY_END)) dup_end = nft_set_ext_key_end(&dup->ext); else dup_end = dup_key; if (!memcmp(start, dup_key->data, set->klen) && !memcmp(end, dup_end->data, set->klen)) { *elem_priv = &dup->priv; return -EEXIST; } return -ENOTEMPTY; } /* Look for partially overlapping entries */ dup = pipapo_get(m, end, nft_genmask_next(net), tstamp); if (dup) { *elem_priv = &dup->priv; return -ENOTEMPTY; } /* Validate */ start_p = start; end_p = end; /* some helpers return -1, or 0 >= for valid rule pos, * so we cannot support more than INT_MAX rules at this time. */ BUILD_BUG_ON(NFT_PIPAPO_RULE0_MAX > INT_MAX); nft_pipapo_for_each_field(f, i, m) { if (f->rules >= NFT_PIPAPO_RULE0_MAX) return -ENOSPC; if (memcmp(start_p, end_p, f->groups / NFT_PIPAPO_GROUPS_PER_BYTE(f)) > 0) return -EINVAL; start_p += NFT_PIPAPO_GROUPS_PADDED_SIZE(f); end_p += NFT_PIPAPO_GROUPS_PADDED_SIZE(f); } /* Insert */ bsize_max = m->bsize_max; nft_pipapo_for_each_field(f, i, m) { int ret; rulemap[i].to = f->rules; ret = memcmp(start, end, f->groups / NFT_PIPAPO_GROUPS_PER_BYTE(f)); if (!ret) ret = pipapo_insert(f, start, f->groups * f->bb); else ret = pipapo_expand(f, start, end, f->groups * f->bb); if (ret < 0) return ret; if (f->bsize > bsize_max) bsize_max = f->bsize; rulemap[i].n = ret; start += NFT_PIPAPO_GROUPS_PADDED_SIZE(f); end += NFT_PIPAPO_GROUPS_PADDED_SIZE(f); } if (!*get_cpu_ptr(m->scratch) || bsize_max > m->bsize_max) { put_cpu_ptr(m->scratch); err = pipapo_realloc_scratch(m, bsize_max); if (err) return err; m->bsize_max = bsize_max; } else { put_cpu_ptr(m->scratch); } e = nft_elem_priv_cast(elem->priv); *elem_priv = &e->priv; pipapo_map(m, rulemap, e); return 0; } /** * pipapo_clone() - Clone matching data to create new working copy * @old: Existing matching data * * Return: copy of matching data passed as 'old' or NULL. */ static struct nft_pipapo_match *pipapo_clone(struct nft_pipapo_match *old) { struct nft_pipapo_field *dst, *src; struct nft_pipapo_match *new; int i; new = kmalloc_flex(*new, f, old->field_count, GFP_KERNEL_ACCOUNT); if (!new) return NULL; new->field_count = old->field_count; new->bsize_max = old->bsize_max; new->scratch = alloc_percpu(*new->scratch); if (!new->scratch) goto out_scratch; for_each_possible_cpu(i) *per_cpu_ptr(new->scratch, i) = NULL; if (pipapo_realloc_scratch(new, old->bsize_max)) goto out_scratch_realloc; rcu_head_init(&new->rcu); src = old->f; dst = new->f; for (i = 0; i < old->field_count; i++) { unsigned long *new_lt; ssize_t lt_size; memcpy(dst, src, offsetof(struct nft_pipapo_field, lt)); lt_size = lt_calculate_size(src->groups, src->bb, src->bsize); if (lt_size < 0) goto out_lt; new_lt = kvzalloc(lt_size, GFP_KERNEL_ACCOUNT); if (!new_lt) goto out_lt; dst->lt = new_lt; memcpy(NFT_PIPAPO_LT_ALIGN(new_lt), NFT_PIPAPO_LT_ALIGN(src->lt), src->bsize * sizeof(*dst->lt) * src->groups * NFT_PIPAPO_BUCKETS(src->bb)); if (src->rules > 0) { if (src->rules_alloc > (INT_MAX / sizeof(*src->mt))) goto out_mt; dst->mt = kvmalloc_objs(*src->mt, src->rules_alloc, GFP_KERNEL_ACCOUNT); if (!dst->mt) goto out_mt; memcpy(dst->mt, src->mt, src->rules * sizeof(*src->mt)); } else { dst->mt = NULL; dst->rules_alloc = 0; } src++; dst++; } return new; out_mt: kvfree(dst->lt); out_lt: for (dst--; i > 0; i--) { kvfree(dst->mt); kvfree(dst->lt); dst--; } out_scratch_realloc: for_each_possible_cpu(i) pipapo_free_scratch(new, i); out_scratch: free_percpu(new->scratch); kfree(new); return NULL; } /** * pipapo_rules_same_key() - Get number of rules originated from the same entry * @f: Field containing mapping table * @first: Index of first rule in set of rules mapping to same entry * * Using the fact that all rules in a field that originated from the same entry * will map to the same set of rules in the next field, or to the same element * reference, return the cardinality of the set of rules that originated from * the same entry as the rule with index @first, @first rule included. * * In pictures: * rules * field #0 0 1 2 3 4 * map to: 0 1 2-4 2-4 5-9 * . . ....... . ... * | | | | \ \ * | | | | \ \ * | | | | \ \ * ' ' ' ' ' \ * in field #1 0 1 2 3 4 5 ... * * if this is called for rule 2 on field #0, it will return 3, as also rules 2 * and 3 in field 0 map to the same set of rules (2, 3, 4) in the next field. * * For the last field in a set, we can rely on associated entries to map to the * same element references. * * Return: Number of rules that originated from the same entry as @first. */ static unsigned int pipapo_rules_same_key(struct nft_pipapo_field *f, unsigned int first) { struct nft_pipapo_elem *e = NULL; /* Keep gcc happy */ unsigned int r; for (r = first; r < f->rules; r++) { if (r != first && e != f->mt[r].e) return r - first; e = f->mt[r].e; } if (r != first) return r - first; return 0; } /** * pipapo_unmap() - Remove rules from mapping tables, renumber remaining ones * @mt: Mapping array * @rules: Original amount of rules in mapping table * @start: First rule index to be removed * @n: Amount of rules to be removed * @to_offset: First rule index, in next field, this group of rules maps to * @is_last: If this is the last field, delete reference from mapping array * * This is used to unmap rules from the mapping table for a single field, * maintaining consistency and compactness for the existing ones. * * In pictures: let's assume that we want to delete rules 2 and 3 from the * following mapping array: * * rules * 0 1 2 3 4 * map to: 4-10 4-10 11-15 11-15 16-18 * * the result will be: * * rules * 0 1 2 * map to: 4-10 4-10 11-13 * * for fields before the last one. In case this is the mapping table for the * last field in a set, and rules map to pointers to &struct nft_pipapo_elem: * * rules * 0 1 2 3 4 * element pointers: 0x42 0x42 0x33 0x33 0x44 * * the result will be: * * rules * 0 1 2 * element pointers: 0x42 0x42 0x44 */ static void pipapo_unmap(union nft_pipapo_map_bucket *mt, unsigned int rules, unsigned int start, unsigned int n, unsigned int to_offset, bool is_last) { int i; memmove(mt + start, mt + start + n, (rules - start - n) * sizeof(*mt)); memset(mt + rules - n, 0, n * sizeof(*mt)); if (is_last) return; for (i = start; i < rules - n; i++) mt[i].to -= to_offset; } /** * pipapo_drop() - Delete entry from lookup and mapping tables, given rule map * @m: Matching data * @rulemap: Table of rule maps, arrays of first rule and amount of rules * in next field a given entry maps to, for each field * * For each rule in lookup table buckets mapping to this set of rules, drop * all bits set in lookup table mapping. In pictures, assuming we want to drop * rules 0 and 1 from this lookup table: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * 0 0 1,2 * 1 1,2 0 * 2 0 1,2 * 3 0 1,2 * 4 0,1,2 * 5 0 1 2 * 6 0,1,2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 * 7 1,2 1,2 1 1 1 0,1 1 1 1 1 1 1 1 1 1 1 * * rule 2 becomes rule 0, and the result will be: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * 0 0 * 1 0 * 2 0 * 3 0 * 4 0 * 5 0 * 6 0 * 7 0 0 * * once this is done, call unmap() to drop all the corresponding rule references * from mapping tables. */ static void pipapo_drop(struct nft_pipapo_match *m, union nft_pipapo_map_bucket rulemap[]) { struct nft_pipapo_field *f; int i; nft_pipapo_for_each_field(f, i, m) { bool last = i == m->field_count - 1; int g; for (g = 0; g < f->groups; g++) { unsigned long *pos; int b; pos = NFT_PIPAPO_LT_ALIGN(f->lt) + g * NFT_PIPAPO_BUCKETS(f->bb) * f->bsize; for (b = 0; b < NFT_PIPAPO_BUCKETS(f->bb); b++) { bitmap_cut(pos, pos, rulemap[i].to, rulemap[i].n, f->bsize * BITS_PER_LONG); pos += f->bsize; } } pipapo_unmap(f->mt, f->rules, rulemap[i].to, rulemap[i].n, last ? 0 : rulemap[i + 1].n, last); if (pipapo_resize(f, f->rules, f->rules - rulemap[i].n)) { /* We can ignore this, a failure to shrink tables down * doesn't make tables invalid. */ ; } f->rules -= rulemap[i].n; pipapo_lt_bits_adjust(f); } } static void nft_pipapo_gc_deactivate(struct net *net, struct nft_set *set, struct nft_pipapo_elem *e) { nft_setelem_data_deactivate(net, set, &e->priv); } /** * pipapo_gc_scan() - Drop expired entries from set and link them to gc list * @set: nftables API set representation * @m: Matching data */ static void pipapo_gc_scan(struct nft_set *set, struct nft_pipapo_match *m) { struct nft_pipapo *priv = nft_set_priv(set); struct net *net = read_pnet(&set->net); unsigned int rules_f0, first_rule = 0; u64 tstamp = nft_net_tstamp(net); struct nft_pipapo_elem *e; struct nft_trans_gc *gc; gc = nft_trans_gc_alloc(set, 0, GFP_KERNEL); if (!gc) return; list_add(&gc->list, &priv->gc_head); while ((rules_f0 = pipapo_rules_same_key(m->f, first_rule))) { union nft_pipapo_map_bucket rulemap[NFT_PIPAPO_MAX_FIELDS]; const struct nft_pipapo_field *f; unsigned int i, start, rules_fx; start = first_rule; rules_fx = rules_f0; nft_pipapo_for_each_field(f, i, m) { rulemap[i].to = start; rulemap[i].n = rules_fx; if (i < m->field_count - 1) { rules_fx = f->mt[start].n; start = f->mt[start].to; } } /* Pick the last field, and its last index */ f--; i--; e = f->mt[rulemap[i].to].e; /* synchronous gc never fails, there is no need to set on * NFT_SET_ELEM_DEAD_BIT. */ if (__nft_set_elem_expired(&e->ext, tstamp)) { if (!nft_trans_gc_space(gc)) { gc = nft_trans_gc_alloc(set, 0, GFP_KERNEL); if (!gc) return; list_add(&gc->list, &priv->gc_head); } nft_pipapo_gc_deactivate(net, set, e); pipapo_drop(m, rulemap); nft_trans_gc_elem_add(gc, e); /* And check again current first rule, which is now the * first we haven't checked. */ } else { first_rule += rules_f0; } } priv->last_gc = jiffies; } /** * pipapo_gc_queue() - Free expired elements * @set: nftables API set representation */ static void pipapo_gc_queue(struct nft_set *set) { struct nft_pipapo *priv = nft_set_priv(set); struct nft_trans_gc *gc, *next; /* always do a catchall cycle: */ gc = nft_trans_gc_alloc(set, 0, GFP_KERNEL); if (gc) { gc = nft_trans_gc_catchall_sync(gc); if (gc) nft_trans_gc_queue_sync_done(gc); } /* always purge queued gc elements. */ list_for_each_entry_safe(gc, next, &priv->gc_head, list) { list_del(&gc->list); nft_trans_gc_queue_sync_done(gc); } } /** * pipapo_free_fields() - Free per-field tables contained in matching data * @m: Matching data */ static void pipapo_free_fields(struct nft_pipapo_match *m) { struct nft_pipapo_field *f; int i; nft_pipapo_for_each_field(f, i, m) { kvfree(f->lt); kvfree(f->mt); } } static void pipapo_free_match(struct nft_pipapo_match *m) { int i; for_each_possible_cpu(i) pipapo_free_scratch(m, i); free_percpu(m->scratch); pipapo_free_fields(m); kfree(m); } /** * pipapo_reclaim_match - RCU callback to free fields from old matching data * @rcu: RCU head */ static void pipapo_reclaim_match(struct rcu_head *rcu) { struct nft_pipapo_match *m; m = container_of(rcu, struct nft_pipapo_match, rcu); pipapo_free_match(m); } /** * nft_pipapo_commit() - Replace lookup data with current working copy * @set: nftables API set representation * * While at it, check if we should perform garbage collection on the working * copy before committing it for lookup, and don't replace the table if the * working copy doesn't have pending changes. * * We also need to create a new working copy for subsequent insertions and * deletions. * * After the live copy has been replaced by the clone, we can safely queue * expired elements that have been collected by pipapo_gc_scan() for * memory reclaim. */ static void nft_pipapo_commit(struct nft_set *set) { struct nft_pipapo *priv = nft_set_priv(set); struct nft_pipapo_match *old; if (!priv->clone) return; if (time_after_eq(jiffies, priv->last_gc + nft_set_gc_interval(set))) pipapo_gc_scan(set, priv->clone); old = rcu_replace_pointer(priv->match, priv->clone, nft_pipapo_transaction_mutex_held(set)); priv->clone = NULL; if (old) call_rcu(&old->rcu, pipapo_reclaim_match); pipapo_gc_queue(set); } static void nft_pipapo_abort(const struct nft_set *set) { struct nft_pipapo *priv = nft_set_priv(set); if (!priv->clone) return; pipapo_free_match(priv->clone); priv->clone = NULL; } /** * nft_pipapo_activate() - Mark element reference as active given key, commit * @net: Network namespace * @set: nftables API set representation * @elem_priv: nftables API element representation containing key data * * On insertion, elements are added to a copy of the matching data currently * in use for lookups, and not directly inserted into current lookup data. Both * nft_pipapo_insert() and nft_pipapo_activate() are called once for each * element, hence we can't purpose either one as a real commit operation. */ static void nft_pipapo_activate(const struct net *net, const struct nft_set *set, struct nft_elem_priv *elem_priv) { struct nft_pipapo_elem *e = nft_elem_priv_cast(elem_priv); nft_clear(net, &e->ext); } /** * nft_pipapo_deactivate() - Search for element and make it inactive * @net: Network namespace * @set: nftables API set representation * @elem: nftables API element representation containing key data * * Return: deactivated element if found, NULL otherwise. */ static struct nft_elem_priv * nft_pipapo_deactivate(const struct net *net, const struct nft_set *set, const struct nft_set_elem *elem) { struct nft_pipapo_match *m = pipapo_maybe_clone(set); struct nft_pipapo_elem *e; /* removal must occur on priv->clone, if we are low on memory * we have no choice and must fail the removal request. */ if (!m) return NULL; e = pipapo_get(m, (const u8 *)elem->key.val.data, nft_genmask_next(net), nft_net_tstamp(net)); if (!e) return NULL; nft_set_elem_change_active(net, set, &e->ext); return &e->priv; } /** * nft_pipapo_flush() - make element inactive * @net: Network namespace * @set: nftables API set representation * @elem_priv: nftables API element representation containing key data * * This is functionally the same as nft_pipapo_deactivate(), with a slightly * different interface, and it's also called once for each element in a set * being flushed, so we can't implement, strictly speaking, a flush operation, * which would otherwise be as simple as allocating an empty copy of the * matching data. * * Note that we could in theory do that, mark the set as flushed, and ignore * subsequent calls, but we would leak all the elements after the first one, * because they wouldn't then be freed as result of API calls. * * Return: true if element was found and deactivated. */ static void nft_pipapo_flush(const struct net *net, const struct nft_set *set, struct nft_elem_priv *elem_priv) { struct nft_pipapo_elem *e = nft_elem_priv_cast(elem_priv); nft_set_elem_change_active(net, set, &e->ext); } /** * pipapo_get_boundaries() - Get byte interval for associated rules * @f: Field including lookup table * @first_rule: First rule (lowest index) * @rule_count: Number of associated rules * @left: Byte expression for left boundary (start of range) * @right: Byte expression for right boundary (end of range) * * Given the first rule and amount of rules that originated from the same entry, * build the original range associated with the entry, and calculate the length * of the originating netmask. * * In pictures: * * bucket * group 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 * 0 1,2 * 1 1,2 * 2 1,2 * 3 1,2 * 4 1,2 * 5 1 2 * 6 1,2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 * 7 1,2 1,2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 * * this is the lookup table corresponding to the IPv4 range * 192.168.1.0-192.168.2.1, which was expanded to the two composing netmasks, * rule #1: 192.168.1.0/24, and rule #2: 192.168.2.0/31. * * This function fills @left and @right with the byte values of the leftmost * and rightmost bucket indices for the lowest and highest rule indices, * respectively. If @first_rule is 1 and @rule_count is 2, we obtain, in * nibbles: * left: < 12, 0, 10, 8, 0, 1, 0, 0 > * right: < 12, 0, 10, 8, 0, 2, 2, 1 > * corresponding to bytes: * left: < 192, 168, 1, 0 > * right: < 192, 168, 2, 1 > * with mask length irrelevant here, unused on return, as the range is already * defined by its start and end points. The mask length is relevant for a single * ranged entry instead: if @first_rule is 1 and @rule_count is 1, we ignore * rule 2 above: @left becomes < 192, 168, 1, 0 >, @right becomes * < 192, 168, 1, 255 >, and the mask length, calculated from the distances * between leftmost and rightmost bucket indices for each group, would be 24. * * Return: mask length, in bits. */ static int pipapo_get_boundaries(struct nft_pipapo_field *f, int first_rule, int rule_count, u8 *left, u8 *right) { int g, mask_len = 0, bit_offset = 0; u8 *l = left, *r = right; for (g = 0; g < f->groups; g++) { int b, x0, x1; x0 = -1; x1 = -1; for (b = 0; b < NFT_PIPAPO_BUCKETS(f->bb); b++) { unsigned long *pos; pos = NFT_PIPAPO_LT_ALIGN(f->lt) + (g * NFT_PIPAPO_BUCKETS(f->bb) + b) * f->bsize; if (test_bit(first_rule, pos) && x0 == -1) x0 = b; if (test_bit(first_rule + rule_count - 1, pos)) x1 = b; } *l |= x0 << (BITS_PER_BYTE - f->bb - bit_offset); *r |= x1 << (BITS_PER_BYTE - f->bb - bit_offset); bit_offset += f->bb; if (bit_offset >= BITS_PER_BYTE) { bit_offset %= BITS_PER_BYTE; l++; r++; } if (x1 - x0 == 0) mask_len += 4; else if (x1 - x0 == 1) mask_len += 3; else if (x1 - x0 == 3) mask_len += 2; else if (x1 - x0 == 7) mask_len += 1; } return mask_len; } /** * pipapo_match_field() - Match rules against byte ranges * @f: Field including the lookup table * @first_rule: First of associated rules originating from same entry * @rule_count: Amount of associated rules * @start: Start of range to be matched * @end: End of range to be matched * * Return: true on match, false otherwise. */ static bool pipapo_match_field(struct nft_pipapo_field *f, int first_rule, int rule_count, const u8 *start, const u8 *end) { u8 right[NFT_PIPAPO_MAX_BYTES] = { 0 }; u8 left[NFT_PIPAPO_MAX_BYTES] = { 0 }; pipapo_get_boundaries(f, first_rule, rule_count, left, right); return !memcmp(start, left, f->groups / NFT_PIPAPO_GROUPS_PER_BYTE(f)) && !memcmp(end, right, f->groups / NFT_PIPAPO_GROUPS_PER_BYTE(f)); } /** * nft_pipapo_remove() - Remove element given key, commit * @net: Network namespace * @set: nftables API set representation * @elem_priv: nftables API element representation containing key data * * Similarly to nft_pipapo_activate(), this is used as commit operation by the * API, but it's called once per element in the pending transaction, so we can't * implement this as a single commit operation. Closest we can get is to remove * the matched element here, if any, and commit the updated matching data. */ static void nft_pipapo_remove(const struct net *net, const struct nft_set *set, struct nft_elem_priv *elem_priv) { struct nft_pipapo *priv = nft_set_priv(set); struct nft_pipapo_match *m = priv->clone; unsigned int rules_f0, first_rule = 0; struct nft_pipapo_elem *e; const u8 *data; e = nft_elem_priv_cast(elem_priv); data = (const u8 *)nft_set_ext_key(&e->ext); while ((rules_f0 = pipapo_rules_same_key(m->f, first_rule))) { union nft_pipapo_map_bucket rulemap[NFT_PIPAPO_MAX_FIELDS]; const u8 *match_start, *match_end; struct nft_pipapo_field *f; int i, start, rules_fx; match_start = data; if (nft_set_ext_exists(&e->ext, NFT_SET_EXT_KEY_END)) match_end = (const u8 *)nft_set_ext_key_end(&e->ext)->data; else match_end = data; start = first_rule; rules_fx = rules_f0; nft_pipapo_for_each_field(f, i, m) { bool last = i == m->field_count - 1; if (!pipapo_match_field(f, start, rules_fx, match_start, match_end)) break; rulemap[i].to = start; rulemap[i].n = rules_fx; rules_fx = f->mt[start].n; start = f->mt[start].to; match_start += NFT_PIPAPO_GROUPS_PADDED_SIZE(f); match_end += NFT_PIPAPO_GROUPS_PADDED_SIZE(f); if (last && f->mt[rulemap[i].to].e == e) { pipapo_drop(m, rulemap); return; } } first_rule += rules_f0; } WARN_ON_ONCE(1); /* elem_priv not found */ } /** * nft_pipapo_do_walk() - Walk over elements in m * @ctx: nftables API context * @set: nftables API set representation * @m: matching data pointing to key mapping array * @iter: Iterator * * As elements are referenced in the mapping array for the last field, directly * scan that array: there's no need to follow rule mappings from the first * field. @m is protected either by RCU read lock or by transaction mutex. */ static void nft_pipapo_do_walk(const struct nft_ctx *ctx, struct nft_set *set, const struct nft_pipapo_match *m, struct nft_set_iter *iter) { const struct nft_pipapo_field *f; unsigned int i, r; for (i = 0, f = m->f; i < m->field_count - 1; i++, f++) ; for (r = 0; r < f->rules; r++) { struct nft_pipapo_elem *e; if (r < f->rules - 1 && f->mt[r + 1].e == f->mt[r].e) continue; if (iter->count < iter->skip) goto cont; e = f->mt[r].e; iter->err = iter->fn(ctx, set, iter, &e->priv); if (iter->err < 0) return; cont: iter->count++; } } /** * nft_pipapo_walk() - Walk over elements * @ctx: nftables API context * @set: nftables API set representation * @iter: Iterator * * Test if destructive action is needed or not, clone active backend if needed * and call the real function to work on the data. */ static void nft_pipapo_walk(const struct nft_ctx *ctx, struct nft_set *set, struct nft_set_iter *iter) { struct nft_pipapo *priv = nft_set_priv(set); const struct nft_pipapo_match *m; switch (iter->type) { case NFT_ITER_UPDATE_CLONE: m = pipapo_maybe_clone(set); if (!m) { iter->err = -ENOMEM; return; } nft_pipapo_do_walk(ctx, set, m, iter); break; case NFT_ITER_UPDATE: if (priv->clone) m = priv->clone; else m = rcu_dereference_protected(priv->match, nft_pipapo_transaction_mutex_held(set)); nft_pipapo_do_walk(ctx, set, m, iter); break; case NFT_ITER_READ: rcu_read_lock(); m = rcu_dereference(priv->match); nft_pipapo_do_walk(ctx, set, m, iter); rcu_read_unlock(); break; default: iter->err = -EINVAL; WARN_ON_ONCE(1); break; } } /** * nft_pipapo_privsize() - Return the size of private data for the set * @nla: netlink attributes, ignored as size doesn't depend on them * @desc: Set description, ignored as size doesn't depend on it * * Return: size of private data for this set implementation, in bytes */ static u64 nft_pipapo_privsize(const struct nlattr * const nla[], const struct nft_set_desc *desc) { return sizeof(struct nft_pipapo); } /** * nft_pipapo_estimate() - Set size, space and lookup complexity * @desc: Set description, element count and field description used * @features: Flags: NFT_SET_INTERVAL needs to be there * @est: Storage for estimation data * * Return: true if set description is compatible, false otherwise */ static bool nft_pipapo_estimate(const struct nft_set_desc *desc, u32 features, struct nft_set_estimate *est) { if (!(features & NFT_SET_INTERVAL) || desc->field_count < NFT_PIPAPO_MIN_FIELDS) return false; est->size = pipapo_estimate_size(desc); if (!est->size) return false; est->lookup = NFT_SET_CLASS_O_LOG_N; est->space = NFT_SET_CLASS_O_N; return true; } /** * nft_pipapo_init() - Initialise data for a set instance * @set: nftables API set representation * @desc: Set description * @nla: netlink attributes * * Validate number and size of fields passed as NFTA_SET_DESC_CONCAT netlink * attributes, initialise internal set parameters, current instance of matching * data and a copy for subsequent insertions. * * Return: 0 on success, negative error code on failure. */ static int nft_pipapo_init(const struct nft_set *set, const struct nft_set_desc *desc, const struct nlattr * const nla[]) { struct nft_pipapo *priv = nft_set_priv(set); struct nft_pipapo_match *m; struct nft_pipapo_field *f; int err, i, field_count; BUILD_BUG_ON(offsetof(struct nft_pipapo_elem, priv) != 0); field_count = desc->field_count ? : 1; BUILD_BUG_ON(NFT_PIPAPO_MAX_FIELDS > 255); BUILD_BUG_ON(NFT_PIPAPO_MAX_FIELDS != NFT_REG32_COUNT); if (field_count > NFT_PIPAPO_MAX_FIELDS) return -EINVAL; m = kmalloc_flex(*m, f, field_count); if (!m) return -ENOMEM; m->field_count = field_count; m->bsize_max = 0; m->scratch = alloc_percpu(struct nft_pipapo_scratch *); if (!m->scratch) { err = -ENOMEM; goto out_scratch; } for_each_possible_cpu(i) *per_cpu_ptr(m->scratch, i) = NULL; rcu_head_init(&m->rcu); nft_pipapo_for_each_field(f, i, m) { unsigned int len = desc->field_len[i] ? : set->klen; /* f->groups is u8 */ BUILD_BUG_ON((NFT_PIPAPO_MAX_BYTES * BITS_PER_BYTE / NFT_PIPAPO_GROUP_BITS_LARGE_SET) >= 256); f->bb = NFT_PIPAPO_GROUP_BITS_INIT; f->groups = len * NFT_PIPAPO_GROUPS_PER_BYTE(f); priv->width += round_up(len, sizeof(u32)); f->bsize = 0; f->rules = 0; f->rules_alloc = 0; f->lt = NULL; f->mt = NULL; } INIT_LIST_HEAD(&priv->gc_head); rcu_assign_pointer(priv->match, m); return 0; out_scratch: kfree(m); return err; } /** * nft_set_pipapo_match_destroy() - Destroy elements from key mapping array * @ctx: context * @set: nftables API set representation * @m: matching data pointing to key mapping array */ static void nft_set_pipapo_match_destroy(const struct nft_ctx *ctx, const struct nft_set *set, struct nft_pipapo_match *m) { struct nft_pipapo_field *f; unsigned int i, r; for (i = 0, f = m->f; i < m->field_count - 1; i++, f++) ; for (r = 0; r < f->rules; r++) { struct nft_pipapo_elem *e; if (r < f->rules - 1 && f->mt[r + 1].e == f->mt[r].e) continue; e = f->mt[r].e; nf_tables_set_elem_destroy(ctx, set, &e->priv); } } /** * nft_pipapo_destroy() - Free private data for set and all committed elements * @ctx: context * @set: nftables API set representation */ static void nft_pipapo_destroy(const struct nft_ctx *ctx, const struct nft_set *set) { struct nft_pipapo *priv = nft_set_priv(set); struct nft_pipapo_match *m; WARN_ON_ONCE(!list_empty(&priv->gc_head)); m = rcu_dereference_protected(priv->match, true); if (priv->clone) { nft_set_pipapo_match_destroy(ctx, set, priv->clone); pipapo_free_match(priv->clone); priv->clone = NULL; } else { nft_set_pipapo_match_destroy(ctx, set, m); } pipapo_free_match(m); } /** * nft_pipapo_gc_init() - Initialise garbage collection * @set: nftables API set representation * * Instead of actually setting up a periodic work for garbage collection, as * this operation requires a swap of matching data with the working copy, we'll * do that opportunistically with other commit operations if the interval is * elapsed, so we just need to set the current jiffies timestamp here. */ static void nft_pipapo_gc_init(const struct nft_set *set) { struct nft_pipapo *priv = nft_set_priv(set); priv->last_gc = jiffies; } const struct nft_set_type nft_set_pipapo_type = { .features = NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_OBJECT | NFT_SET_TIMEOUT, .ops = { .lookup = nft_pipapo_lookup, .insert = nft_pipapo_insert, .activate = nft_pipapo_activate, .deactivate = nft_pipapo_deactivate, .flush = nft_pipapo_flush, .remove = nft_pipapo_remove, .walk = nft_pipapo_walk, .get = nft_pipapo_get, .privsize = nft_pipapo_privsize, .estimate = nft_pipapo_estimate, .init = nft_pipapo_init, .destroy = nft_pipapo_destroy, .gc_init = nft_pipapo_gc_init, .commit = nft_pipapo_commit, .abort = nft_pipapo_abort, .abort_skip_removal = true, .elemsize = offsetof(struct nft_pipapo_elem, ext), }, }; #if defined(CONFIG_X86_64) && !defined(CONFIG_UML) const struct nft_set_type nft_set_pipapo_avx2_type = { .features = NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_OBJECT | NFT_SET_TIMEOUT, .ops = { .lookup = nft_pipapo_avx2_lookup, .insert = nft_pipapo_insert, .activate = nft_pipapo_activate, .deactivate = nft_pipapo_deactivate, .flush = nft_pipapo_flush, .remove = nft_pipapo_remove, .walk = nft_pipapo_walk, .get = nft_pipapo_get, .privsize = nft_pipapo_privsize, .estimate = nft_pipapo_avx2_estimate, .init = nft_pipapo_init, .destroy = nft_pipapo_destroy, .gc_init = nft_pipapo_gc_init, .commit = nft_pipapo_commit, .abort = nft_pipapo_abort, .abort_skip_removal = true, .elemsize = offsetof(struct nft_pipapo_elem, ext), }, }; #endif
