From b95a5c4db09bc7c253636cb84dc9b12c577fd5a0 Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Sat, 21 Jan 2017 17:26:11 +0100 Subject: [PATCH 1/3] bpf: add a longest prefix match trie map implementation This trie implements a longest prefix match algorithm that can be used to match IP addresses to a stored set of ranges. Internally, data is stored in an unbalanced trie of nodes that has a maximum height of n, where n is the prefixlen the trie was created with. Tries may be created with prefix lengths that are multiples of 8, in the range from 8 to 2048. The key used for lookup and update operations is a struct bpf_lpm_trie_key, and the value is a uint64_t. The code carries more information about the internal implementation. Signed-off-by: Daniel Mack Reviewed-by: David Herrmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/uapi/linux/bpf.h | 7 + kernel/bpf/Makefile | 2 +- kernel/bpf/lpm_trie.c | 503 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 511 insertions(+), 1 deletion(-) create mode 100644 kernel/bpf/lpm_trie.c diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 54a5894bb4ea39..bd306848541017 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -63,6 +63,12 @@ struct bpf_insn { __s32 imm; /* signed immediate constant */ }; +/* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */ +struct bpf_lpm_trie_key { + __u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */ + __u8 data[0]; /* Arbitrary size */ +}; + /* BPF syscall commands, see bpf(2) man-page for details. */ enum bpf_cmd { BPF_MAP_CREATE, @@ -89,6 +95,7 @@ enum bpf_map_type { BPF_MAP_TYPE_CGROUP_ARRAY, BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH, + BPF_MAP_TYPE_LPM_TRIE, }; enum bpf_prog_type { diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 1276474ac3cd9d..e1ce4f4fd7fd47 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -1,7 +1,7 @@ obj-y := core.o obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o -obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o +obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o ifeq ($(CONFIG_PERF_EVENTS),y) obj-$(CONFIG_BPF_SYSCALL) += stackmap.o endif diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c new file mode 100644 index 00000000000000..ba19241d1979bc --- /dev/null +++ b/kernel/bpf/lpm_trie.c @@ -0,0 +1,503 @@ +/* + * Longest prefix match list implementation + * + * Copyright (c) 2016,2017 Daniel Mack + * Copyright (c) 2016 David Herrmann + * + * This file is subject to the terms and conditions of version 2 of the GNU + * General Public License. See the file COPYING in the main directory of the + * Linux distribution for more details. + */ + +#include +#include +#include +#include +#include +#include + +/* Intermediate node */ +#define LPM_TREE_NODE_FLAG_IM BIT(0) + +struct lpm_trie_node; + +struct lpm_trie_node { + struct rcu_head rcu; + struct lpm_trie_node __rcu *child[2]; + u32 prefixlen; + u32 flags; + u8 data[0]; +}; + +struct lpm_trie { + struct bpf_map map; + struct lpm_trie_node __rcu *root; + size_t n_entries; + size_t max_prefixlen; + size_t data_size; + raw_spinlock_t lock; +}; + +/* This trie implements a longest prefix match algorithm that can be used to + * match IP addresses to a stored set of ranges. + * + * Data stored in @data of struct bpf_lpm_key and struct lpm_trie_node is + * interpreted as big endian, so data[0] stores the most significant byte. + * + * Match ranges are internally stored in instances of struct lpm_trie_node + * which each contain their prefix length as well as two pointers that may + * lead to more nodes containing more specific matches. Each node also stores + * a value that is defined by and returned to userspace via the update_elem + * and lookup functions. + * + * For instance, let's start with a trie that was created with a prefix length + * of 32, so it can be used for IPv4 addresses, and one single element that + * matches 192.168.0.0/16. The data array would hence contain + * [0xc0, 0xa8, 0x00, 0x00] in big-endian notation. This documentation will + * stick to IP-address notation for readability though. + * + * As the trie is empty initially, the new node (1) will be places as root + * node, denoted as (R) in the example below. As there are no other node, both + * child pointers are %NULL. + * + * +----------------+ + * | (1) (R) | + * | 192.168.0.0/16 | + * | value: 1 | + * | [0] [1] | + * +----------------+ + * + * Next, let's add a new node (2) matching 192.168.0.0/24. As there is already + * a node with the same data and a smaller prefix (ie, a less specific one), + * node (2) will become a child of (1). In child index depends on the next bit + * that is outside of what (1) matches, and that bit is 0, so (2) will be + * child[0] of (1): + * + * +----------------+ + * | (1) (R) | + * | 192.168.0.0/16 | + * | value: 1 | + * | [0] [1] | + * +----------------+ + * | + * +----------------+ + * | (2) | + * | 192.168.0.0/24 | + * | value: 2 | + * | [0] [1] | + * +----------------+ + * + * The child[1] slot of (1) could be filled with another node which has bit #17 + * (the next bit after the ones that (1) matches on) set to 1. For instance, + * 192.168.128.0/24: + * + * +----------------+ + * | (1) (R) | + * | 192.168.0.0/16 | + * | value: 1 | + * | [0] [1] | + * +----------------+ + * | | + * +----------------+ +------------------+ + * | (2) | | (3) | + * | 192.168.0.0/24 | | 192.168.128.0/24 | + * | value: 2 | | value: 3 | + * | [0] [1] | | [0] [1] | + * +----------------+ +------------------+ + * + * Let's add another node (4) to the game for 192.168.1.0/24. In order to place + * it, node (1) is looked at first, and because (4) of the semantics laid out + * above (bit #17 is 0), it would normally be attached to (1) as child[0]. + * However, that slot is already allocated, so a new node is needed in between. + * That node does not have a value attached to it and it will never be + * returned to users as result of a lookup. It is only there to differentiate + * the traversal further. It will get a prefix as wide as necessary to + * distinguish its two children: + * + * +----------------+ + * | (1) (R) | + * | 192.168.0.0/16 | + * | value: 1 | + * | [0] [1] | + * +----------------+ + * | | + * +----------------+ +------------------+ + * | (4) (I) | | (3) | + * | 192.168.0.0/23 | | 192.168.128.0/24 | + * | value: --- | | value: 3 | + * | [0] [1] | | [0] [1] | + * +----------------+ +------------------+ + * | | + * +----------------+ +----------------+ + * | (2) | | (5) | + * | 192.168.0.0/24 | | 192.168.1.0/24 | + * | value: 2 | | value: 5 | + * | [0] [1] | | [0] [1] | + * +----------------+ +----------------+ + * + * 192.168.1.1/32 would be a child of (5) etc. + * + * An intermediate node will be turned into a 'real' node on demand. In the + * example above, (4) would be re-used if 192.168.0.0/23 is added to the trie. + * + * A fully populated trie would have a height of 32 nodes, as the trie was + * created with a prefix length of 32. + * + * The lookup starts at the root node. If the current node matches and if there + * is a child that can be used to become more specific, the trie is traversed + * downwards. The last node in the traversal that is a non-intermediate one is + * returned. + */ + +static inline int extract_bit(const u8 *data, size_t index) +{ + return !!(data[index / 8] & (1 << (7 - (index % 8)))); +} + +/** + * longest_prefix_match() - determine the longest prefix + * @trie: The trie to get internal sizes from + * @node: The node to operate on + * @key: The key to compare to @node + * + * Determine the longest prefix of @node that matches the bits in @key. + */ +static size_t longest_prefix_match(const struct lpm_trie *trie, + const struct lpm_trie_node *node, + const struct bpf_lpm_trie_key *key) +{ + size_t prefixlen = 0; + size_t i; + + for (i = 0; i < trie->data_size; i++) { + size_t b; + + b = 8 - fls(node->data[i] ^ key->data[i]); + prefixlen += b; + + if (prefixlen >= node->prefixlen || prefixlen >= key->prefixlen) + return min(node->prefixlen, key->prefixlen); + + if (b < 8) + break; + } + + return prefixlen; +} + +/* Called from syscall or from eBPF program */ +static void *trie_lookup_elem(struct bpf_map *map, void *_key) +{ + struct lpm_trie *trie = container_of(map, struct lpm_trie, map); + struct lpm_trie_node *node, *found = NULL; + struct bpf_lpm_trie_key *key = _key; + + /* Start walking the trie from the root node ... */ + + for (node = rcu_dereference(trie->root); node;) { + unsigned int next_bit; + size_t matchlen; + + /* Determine the longest prefix of @node that matches @key. + * If it's the maximum possible prefix for this trie, we have + * an exact match and can return it directly. + */ + matchlen = longest_prefix_match(trie, node, key); + if (matchlen == trie->max_prefixlen) { + found = node; + break; + } + + /* If the number of bits that match is smaller than the prefix + * length of @node, bail out and return the node we have seen + * last in the traversal (ie, the parent). + */ + if (matchlen < node->prefixlen) + break; + + /* Consider this node as return candidate unless it is an + * artificially added intermediate one. + */ + if (!(node->flags & LPM_TREE_NODE_FLAG_IM)) + found = node; + + /* If the node match is fully satisfied, let's see if we can + * become more specific. Determine the next bit in the key and + * traverse down. + */ + next_bit = extract_bit(key->data, node->prefixlen); + node = rcu_dereference(node->child[next_bit]); + } + + if (!found) + return NULL; + + return found->data + trie->data_size; +} + +static struct lpm_trie_node *lpm_trie_node_alloc(const struct lpm_trie *trie, + const void *value) +{ + struct lpm_trie_node *node; + size_t size = sizeof(struct lpm_trie_node) + trie->data_size; + + if (value) + size += trie->map.value_size; + + node = kmalloc(size, GFP_ATOMIC | __GFP_NOWARN); + if (!node) + return NULL; + + node->flags = 0; + + if (value) + memcpy(node->data + trie->data_size, value, + trie->map.value_size); + + return node; +} + +/* Called from syscall or from eBPF program */ +static int trie_update_elem(struct bpf_map *map, + void *_key, void *value, u64 flags) +{ + struct lpm_trie *trie = container_of(map, struct lpm_trie, map); + struct lpm_trie_node *node, *im_node, *new_node = NULL; + struct lpm_trie_node __rcu **slot; + struct bpf_lpm_trie_key *key = _key; + unsigned long irq_flags; + unsigned int next_bit; + size_t matchlen = 0; + int ret = 0; + + if (unlikely(flags > BPF_EXIST)) + return -EINVAL; + + if (key->prefixlen > trie->max_prefixlen) + return -EINVAL; + + raw_spin_lock_irqsave(&trie->lock, irq_flags); + + /* Allocate and fill a new node */ + + if (trie->n_entries == trie->map.max_entries) { + ret = -ENOSPC; + goto out; + } + + new_node = lpm_trie_node_alloc(trie, value); + if (!new_node) { + ret = -ENOMEM; + goto out; + } + + trie->n_entries++; + + new_node->prefixlen = key->prefixlen; + RCU_INIT_POINTER(new_node->child[0], NULL); + RCU_INIT_POINTER(new_node->child[1], NULL); + memcpy(new_node->data, key->data, trie->data_size); + + /* Now find a slot to attach the new node. To do that, walk the tree + * from the root and match as many bits as possible for each node until + * we either find an empty slot or a slot that needs to be replaced by + * an intermediate node. + */ + slot = &trie->root; + + while ((node = rcu_dereference_protected(*slot, + lockdep_is_held(&trie->lock)))) { + matchlen = longest_prefix_match(trie, node, key); + + if (node->prefixlen != matchlen || + node->prefixlen == key->prefixlen || + node->prefixlen == trie->max_prefixlen) + break; + + next_bit = extract_bit(key->data, node->prefixlen); + slot = &node->child[next_bit]; + } + + /* If the slot is empty (a free child pointer or an empty root), + * simply assign the @new_node to that slot and be done. + */ + if (!node) { + rcu_assign_pointer(*slot, new_node); + goto out; + } + + /* If the slot we picked already exists, replace it with @new_node + * which already has the correct data array set. + */ + if (node->prefixlen == matchlen) { + new_node->child[0] = node->child[0]; + new_node->child[1] = node->child[1]; + + if (!(node->flags & LPM_TREE_NODE_FLAG_IM)) + trie->n_entries--; + + rcu_assign_pointer(*slot, new_node); + kfree_rcu(node, rcu); + + goto out; + } + + /* If the new node matches the prefix completely, it must be inserted + * as an ancestor. Simply insert it between @node and *@slot. + */ + if (matchlen == key->prefixlen) { + next_bit = extract_bit(node->data, matchlen); + rcu_assign_pointer(new_node->child[next_bit], node); + rcu_assign_pointer(*slot, new_node); + goto out; + } + + im_node = lpm_trie_node_alloc(trie, NULL); + if (!im_node) { + ret = -ENOMEM; + goto out; + } + + im_node->prefixlen = matchlen; + im_node->flags |= LPM_TREE_NODE_FLAG_IM; + memcpy(im_node->data, node->data, trie->data_size); + + /* Now determine which child to install in which slot */ + if (extract_bit(key->data, matchlen)) { + rcu_assign_pointer(im_node->child[0], node); + rcu_assign_pointer(im_node->child[1], new_node); + } else { + rcu_assign_pointer(im_node->child[0], new_node); + rcu_assign_pointer(im_node->child[1], node); + } + + /* Finally, assign the intermediate node to the determined spot */ + rcu_assign_pointer(*slot, im_node); + +out: + if (ret) { + if (new_node) + trie->n_entries--; + + kfree(new_node); + kfree(im_node); + } + + raw_spin_unlock_irqrestore(&trie->lock, irq_flags); + + return ret; +} + +static int trie_delete_elem(struct bpf_map *map, void *key) +{ + /* TODO */ + return -ENOSYS; +} + +static struct bpf_map *trie_alloc(union bpf_attr *attr) +{ + size_t cost, cost_per_node; + struct lpm_trie *trie; + int ret; + + if (!capable(CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + + /* check sanity of attributes */ + if (attr->max_entries == 0 || + attr->map_flags != BPF_F_NO_PREALLOC || + attr->key_size < sizeof(struct bpf_lpm_trie_key) + 1 || + attr->key_size > sizeof(struct bpf_lpm_trie_key) + 256 || + attr->value_size == 0) + return ERR_PTR(-EINVAL); + + trie = kzalloc(sizeof(*trie), GFP_USER | __GFP_NOWARN); + if (!trie) + return ERR_PTR(-ENOMEM); + + /* copy mandatory map attributes */ + trie->map.map_type = attr->map_type; + trie->map.key_size = attr->key_size; + trie->map.value_size = attr->value_size; + trie->map.max_entries = attr->max_entries; + trie->data_size = attr->key_size - + offsetof(struct bpf_lpm_trie_key, data); + trie->max_prefixlen = trie->data_size * 8; + + cost_per_node = sizeof(struct lpm_trie_node) + + attr->value_size + trie->data_size; + cost = sizeof(*trie) + attr->max_entries * cost_per_node; + trie->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; + + ret = bpf_map_precharge_memlock(trie->map.pages); + if (ret) { + kfree(trie); + return ERR_PTR(ret); + } + + raw_spin_lock_init(&trie->lock); + + return &trie->map; +} + +static void trie_free(struct bpf_map *map) +{ + struct lpm_trie *trie = container_of(map, struct lpm_trie, map); + struct lpm_trie_node __rcu **slot; + struct lpm_trie_node *node; + + raw_spin_lock(&trie->lock); + + /* Always start at the root and walk down to a node that has no + * children. Then free that node, nullify its reference in the parent + * and start over. + */ + + for (;;) { + slot = &trie->root; + + for (;;) { + node = rcu_dereference_protected(*slot, + lockdep_is_held(&trie->lock)); + if (!node) + goto unlock; + + if (rcu_access_pointer(node->child[0])) { + slot = &node->child[0]; + continue; + } + + if (rcu_access_pointer(node->child[1])) { + slot = &node->child[1]; + continue; + } + + kfree(node); + RCU_INIT_POINTER(*slot, NULL); + break; + } + } + +unlock: + raw_spin_unlock(&trie->lock); +} + +static const struct bpf_map_ops trie_ops = { + .map_alloc = trie_alloc, + .map_free = trie_free, + .map_lookup_elem = trie_lookup_elem, + .map_update_elem = trie_update_elem, + .map_delete_elem = trie_delete_elem, +}; + +static struct bpf_map_type_list trie_type __read_mostly = { + .ops = &trie_ops, + .type = BPF_MAP_TYPE_LPM_TRIE, +}; + +static int __init register_trie_map(void) +{ + bpf_register_map_type(&trie_type); + return 0; +} +late_initcall(register_trie_map); From 4d3381f5a322dd5db2477e224821790478488173 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sat, 21 Jan 2017 17:26:12 +0100 Subject: [PATCH 2/3] bpf: Add tests for the lpm trie map The first part of this program runs randomized tests against the lpm-bpf-map. It implements a "Trivial Longest Prefix Match" (tlpm) based on simple, linear, single linked lists. The implementation should be pretty straightforward. Based on tlpm, this inserts randomized data into bpf-lpm-maps and verifies the trie-based bpf-map implementation behaves the same way as tlpm. The second part uses 'real world' IPv4 and IPv6 addresses and tests the trie with those. Signed-off-by: David Herrmann Signed-off-by: Daniel Mack Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- tools/testing/selftests/bpf/.gitignore | 1 + tools/testing/selftests/bpf/Makefile | 4 +- tools/testing/selftests/bpf/test_lpm_map.c | 358 +++++++++++++++++++++ 3 files changed, 361 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/test_lpm_map.c diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore index 071431bedde8fc..d3b1c9bca40717 100644 --- a/tools/testing/selftests/bpf/.gitignore +++ b/tools/testing/selftests/bpf/.gitignore @@ -1,3 +1,4 @@ test_verifier test_maps test_lru_map +test_lpm_map diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 7a5f24543a5f06..064a3e5f28363b 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -1,8 +1,8 @@ CFLAGS += -Wall -O2 -I../../../../usr/include -test_objs = test_verifier test_maps test_lru_map +test_objs = test_verifier test_maps test_lru_map test_lpm_map -TEST_PROGS := test_verifier test_maps test_lru_map test_kmod.sh +TEST_PROGS := test_verifier test_maps test_lru_map test_lpm_map test_kmod.sh TEST_FILES := $(test_objs) all: $(test_objs) diff --git a/tools/testing/selftests/bpf/test_lpm_map.c b/tools/testing/selftests/bpf/test_lpm_map.c new file mode 100644 index 00000000000000..26775c00273fb6 --- /dev/null +++ b/tools/testing/selftests/bpf/test_lpm_map.c @@ -0,0 +1,358 @@ +/* + * Randomized tests for eBPF longest-prefix-match maps + * + * This program runs randomized tests against the lpm-bpf-map. It implements a + * "Trivial Longest Prefix Match" (tlpm) based on simple, linear, singly linked + * lists. The implementation should be pretty straightforward. + * + * Based on tlpm, this inserts randomized data into bpf-lpm-maps and verifies + * the trie-based bpf-map implementation behaves the same way as tlpm. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "bpf_sys.h" +#include "bpf_util.h" + +struct tlpm_node { + struct tlpm_node *next; + size_t n_bits; + uint8_t key[]; +}; + +static struct tlpm_node *tlpm_add(struct tlpm_node *list, + const uint8_t *key, + size_t n_bits) +{ + struct tlpm_node *node; + size_t n; + + /* add new entry with @key/@n_bits to @list and return new head */ + + n = (n_bits + 7) / 8; + node = malloc(sizeof(*node) + n); + assert(node); + + node->next = list; + node->n_bits = n_bits; + memcpy(node->key, key, n); + + return node; +} + +static void tlpm_clear(struct tlpm_node *list) +{ + struct tlpm_node *node; + + /* free all entries in @list */ + + while ((node = list)) { + list = list->next; + free(node); + } +} + +static struct tlpm_node *tlpm_match(struct tlpm_node *list, + const uint8_t *key, + size_t n_bits) +{ + struct tlpm_node *best = NULL; + size_t i; + + /* Perform longest prefix-match on @key/@n_bits. That is, iterate all + * entries and match each prefix against @key. Remember the "best" + * entry we find (i.e., the longest prefix that matches) and return it + * to the caller when done. + */ + + for ( ; list; list = list->next) { + for (i = 0; i < n_bits && i < list->n_bits; ++i) { + if ((key[i / 8] & (1 << (7 - i % 8))) != + (list->key[i / 8] & (1 << (7 - i % 8)))) + break; + } + + if (i >= list->n_bits) { + if (!best || i > best->n_bits) + best = list; + } + } + + return best; +} + +static void test_lpm_basic(void) +{ + struct tlpm_node *list = NULL, *t1, *t2; + + /* very basic, static tests to verify tlpm works as expected */ + + assert(!tlpm_match(list, (uint8_t[]){ 0xff }, 8)); + + t1 = list = tlpm_add(list, (uint8_t[]){ 0xff }, 8); + assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff }, 8)); + assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 16)); + assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0x00 }, 16)); + assert(!tlpm_match(list, (uint8_t[]){ 0x7f }, 8)); + assert(!tlpm_match(list, (uint8_t[]){ 0xfe }, 8)); + assert(!tlpm_match(list, (uint8_t[]){ 0xff }, 7)); + + t2 = list = tlpm_add(list, (uint8_t[]){ 0xff, 0xff }, 16); + assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff }, 8)); + assert(t2 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 16)); + assert(t1 == tlpm_match(list, (uint8_t[]){ 0xff, 0xff }, 15)); + assert(!tlpm_match(list, (uint8_t[]){ 0x7f, 0xff }, 16)); + + tlpm_clear(list); +} + +static void test_lpm_order(void) +{ + struct tlpm_node *t1, *t2, *l1 = NULL, *l2 = NULL; + size_t i, j; + + /* Verify the tlpm implementation works correctly regardless of the + * order of entries. Insert a random set of entries into @l1, and copy + * the same data in reverse order into @l2. Then verify a lookup of + * random keys will yield the same result in both sets. + */ + + for (i = 0; i < (1 << 12); ++i) + l1 = tlpm_add(l1, (uint8_t[]){ + rand() % 0xff, + rand() % 0xff, + }, rand() % 16 + 1); + + for (t1 = l1; t1; t1 = t1->next) + l2 = tlpm_add(l2, t1->key, t1->n_bits); + + for (i = 0; i < (1 << 8); ++i) { + uint8_t key[] = { rand() % 0xff, rand() % 0xff }; + + t1 = tlpm_match(l1, key, 16); + t2 = tlpm_match(l2, key, 16); + + assert(!t1 == !t2); + if (t1) { + assert(t1->n_bits == t2->n_bits); + for (j = 0; j < t1->n_bits; ++j) + assert((t1->key[j / 8] & (1 << (7 - j % 8))) == + (t2->key[j / 8] & (1 << (7 - j % 8)))); + } + } + + tlpm_clear(l1); + tlpm_clear(l2); +} + +static void test_lpm_map(int keysize) +{ + size_t i, j, n_matches, n_nodes, n_lookups; + struct tlpm_node *t, *list = NULL; + struct bpf_lpm_trie_key *key; + uint8_t *data, *value; + int r, map; + + /* Compare behavior of tlpm vs. bpf-lpm. Create a randomized set of + * prefixes and insert it into both tlpm and bpf-lpm. Then run some + * randomized lookups and verify both maps return the same result. + */ + + n_matches = 0; + n_nodes = 1 << 8; + n_lookups = 1 << 16; + + data = alloca(keysize); + memset(data, 0, keysize); + + value = alloca(keysize + 1); + memset(value, 0, keysize + 1); + + key = alloca(sizeof(*key) + keysize); + memset(key, 0, sizeof(*key) + keysize); + + map = bpf_map_create(BPF_MAP_TYPE_LPM_TRIE, + sizeof(*key) + keysize, + keysize + 1, + 4096, + BPF_F_NO_PREALLOC); + assert(map >= 0); + + for (i = 0; i < n_nodes; ++i) { + for (j = 0; j < keysize; ++j) + value[j] = rand() & 0xff; + value[keysize] = rand() % (8 * keysize + 1); + + list = tlpm_add(list, value, value[keysize]); + + key->prefixlen = value[keysize]; + memcpy(key->data, value, keysize); + r = bpf_map_update(map, key, value, 0); + assert(!r); + } + + for (i = 0; i < n_lookups; ++i) { + for (j = 0; j < keysize; ++j) + data[j] = rand() & 0xff; + + t = tlpm_match(list, data, 8 * keysize); + + key->prefixlen = 8 * keysize; + memcpy(key->data, data, keysize); + r = bpf_map_lookup(map, key, value); + assert(!r || errno == ENOENT); + assert(!t == !!r); + + if (t) { + ++n_matches; + assert(t->n_bits == value[keysize]); + for (j = 0; j < t->n_bits; ++j) + assert((t->key[j / 8] & (1 << (7 - j % 8))) == + (value[j / 8] & (1 << (7 - j % 8)))); + } + } + + close(map); + tlpm_clear(list); + + /* With 255 random nodes in the map, we are pretty likely to match + * something on every lookup. For statistics, use this: + * + * printf(" nodes: %zu\n" + * "lookups: %zu\n" + * "matches: %zu\n", n_nodes, n_lookups, n_matches); + */ +} + +/* Test the implementation with some 'real world' examples */ + +static void test_lpm_ipaddr(void) +{ + struct bpf_lpm_trie_key *key_ipv4; + struct bpf_lpm_trie_key *key_ipv6; + size_t key_size_ipv4; + size_t key_size_ipv6; + int map_fd_ipv4; + int map_fd_ipv6; + __u64 value; + + key_size_ipv4 = sizeof(*key_ipv4) + sizeof(__u32); + key_size_ipv6 = sizeof(*key_ipv6) + sizeof(__u32) * 4; + key_ipv4 = alloca(key_size_ipv4); + key_ipv6 = alloca(key_size_ipv6); + + map_fd_ipv4 = bpf_map_create(BPF_MAP_TYPE_LPM_TRIE, + key_size_ipv4, sizeof(value), + 100, BPF_F_NO_PREALLOC); + assert(map_fd_ipv4 >= 0); + + map_fd_ipv6 = bpf_map_create(BPF_MAP_TYPE_LPM_TRIE, + key_size_ipv6, sizeof(value), + 100, BPF_F_NO_PREALLOC); + assert(map_fd_ipv6 >= 0); + + /* Fill data some IPv4 and IPv6 address ranges */ + value = 1; + key_ipv4->prefixlen = 16; + inet_pton(AF_INET, "192.168.0.0", key_ipv4->data); + assert(bpf_map_update(map_fd_ipv4, key_ipv4, &value, 0) == 0); + + value = 2; + key_ipv4->prefixlen = 24; + inet_pton(AF_INET, "192.168.0.0", key_ipv4->data); + assert(bpf_map_update(map_fd_ipv4, key_ipv4, &value, 0) == 0); + + value = 3; + key_ipv4->prefixlen = 24; + inet_pton(AF_INET, "192.168.128.0", key_ipv4->data); + assert(bpf_map_update(map_fd_ipv4, key_ipv4, &value, 0) == 0); + + value = 5; + key_ipv4->prefixlen = 24; + inet_pton(AF_INET, "192.168.1.0", key_ipv4->data); + assert(bpf_map_update(map_fd_ipv4, key_ipv4, &value, 0) == 0); + + value = 4; + key_ipv4->prefixlen = 23; + inet_pton(AF_INET, "192.168.0.0", key_ipv4->data); + assert(bpf_map_update(map_fd_ipv4, key_ipv4, &value, 0) == 0); + + value = 0xdeadbeef; + key_ipv6->prefixlen = 64; + inet_pton(AF_INET6, "2a00:1450:4001:814::200e", key_ipv6->data); + assert(bpf_map_update(map_fd_ipv6, key_ipv6, &value, 0) == 0); + + /* Set tprefixlen to maximum for lookups */ + key_ipv4->prefixlen = 32; + key_ipv6->prefixlen = 128; + + /* Test some lookups that should come back with a value */ + inet_pton(AF_INET, "192.168.128.23", key_ipv4->data); + assert(bpf_map_lookup(map_fd_ipv4, key_ipv4, &value) == 0); + assert(value == 3); + + inet_pton(AF_INET, "192.168.0.1", key_ipv4->data); + assert(bpf_map_lookup(map_fd_ipv4, key_ipv4, &value) == 0); + assert(value == 2); + + inet_pton(AF_INET6, "2a00:1450:4001:814::", key_ipv6->data); + assert(bpf_map_lookup(map_fd_ipv6, key_ipv6, &value) == 0); + assert(value == 0xdeadbeef); + + inet_pton(AF_INET6, "2a00:1450:4001:814::1", key_ipv6->data); + assert(bpf_map_lookup(map_fd_ipv6, key_ipv6, &value) == 0); + assert(value == 0xdeadbeef); + + /* Test some lookups that should not match any entry */ + inet_pton(AF_INET, "10.0.0.1", key_ipv4->data); + assert(bpf_map_lookup(map_fd_ipv4, key_ipv4, &value) == -1 && + errno == ENOENT); + + inet_pton(AF_INET, "11.11.11.11", key_ipv4->data); + assert(bpf_map_lookup(map_fd_ipv4, key_ipv4, &value) == -1 && + errno == ENOENT); + + inet_pton(AF_INET6, "2a00:ffff::", key_ipv6->data); + assert(bpf_map_lookup(map_fd_ipv6, key_ipv6, &value) == -1 && + errno == ENOENT); + + close(map_fd_ipv4); + close(map_fd_ipv6); +} + +int main(void) +{ + struct rlimit limit = { RLIM_INFINITY, RLIM_INFINITY }; + int i, ret; + + /* we want predictable, pseudo random tests */ + srand(0xf00ba1); + + /* allow unlimited locked memory */ + ret = setrlimit(RLIMIT_MEMLOCK, &limit); + if (ret < 0) + perror("Unable to lift memlock rlimit"); + + test_lpm_basic(); + test_lpm_order(); + + /* Test with 8, 16, 24, 32, ... 128 bit prefix length */ + for (i = 1; i <= 16; ++i) + test_lpm_map(i); + + test_lpm_ipaddr(); + + printf("test_lpm: OK\n"); + return 0; +} From b8a943e2942296aad37a8e7adc43db493413e54b Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sat, 21 Jan 2017 17:26:13 +0100 Subject: [PATCH 3/3] samples/bpf: add lpm-trie benchmark Extend the map_perf_test_{user,kern}.c infrastructure to stress test lpm-trie lookups. We hook into the kprobe on sys_gettid() and measure the latency depending on trie size and lookup count. On my Intel Haswell i7-6400U, a single gettid() syscall with an empty bpf program takes roughly 6.5us on my system. Lookups in empty tries take ~1.8us on first try, ~0.9us on retries. Lookups in tries with 8192 entries take ~7.1us (on the first _and_ any subsequent try). Signed-off-by: David Herrmann Reviewed-by: Daniel Mack Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- samples/bpf/map_perf_test_kern.c | 30 +++++++++++++++++++ samples/bpf/map_perf_test_user.c | 49 ++++++++++++++++++++++++++++++++ 2 files changed, 79 insertions(+) diff --git a/samples/bpf/map_perf_test_kern.c b/samples/bpf/map_perf_test_kern.c index 7ee1574c8ccff4..a91872a97742a6 100644 --- a/samples/bpf/map_perf_test_kern.c +++ b/samples/bpf/map_perf_test_kern.c @@ -57,6 +57,14 @@ struct bpf_map_def SEC("maps") percpu_hash_map_alloc = { .map_flags = BPF_F_NO_PREALLOC, }; +struct bpf_map_def SEC("maps") lpm_trie_map_alloc = { + .type = BPF_MAP_TYPE_LPM_TRIE, + .key_size = 8, + .value_size = sizeof(long), + .max_entries = 10000, + .map_flags = BPF_F_NO_PREALLOC, +}; + SEC("kprobe/sys_getuid") int stress_hmap(struct pt_regs *ctx) { @@ -135,5 +143,27 @@ int stress_percpu_lru_hmap_alloc(struct pt_regs *ctx) return 0; } +SEC("kprobe/sys_gettid") +int stress_lpm_trie_map_alloc(struct pt_regs *ctx) +{ + union { + u32 b32[2]; + u8 b8[8]; + } key; + unsigned int i; + + key.b32[0] = 32; + key.b8[4] = 192; + key.b8[5] = 168; + key.b8[6] = 0; + key.b8[7] = 1; + +#pragma clang loop unroll(full) + for (i = 0; i < 32; ++i) + bpf_map_lookup_elem(&lpm_trie_map_alloc, &key); + + return 0; +} + char _license[] SEC("license") = "GPL"; u32 _version SEC("version") = LINUX_VERSION_CODE; diff --git a/samples/bpf/map_perf_test_user.c b/samples/bpf/map_perf_test_user.c index 9505b4d112f426..680260a91f50c8 100644 --- a/samples/bpf/map_perf_test_user.c +++ b/samples/bpf/map_perf_test_user.c @@ -37,6 +37,7 @@ static __u64 time_get_ns(void) #define PERCPU_HASH_KMALLOC (1 << 3) #define LRU_HASH_PREALLOC (1 << 4) #define PERCPU_LRU_HASH_PREALLOC (1 << 5) +#define LPM_KMALLOC (1 << 6) static int test_flags = ~0; @@ -112,6 +113,18 @@ static void test_percpu_hash_kmalloc(int cpu) cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time)); } +static void test_lpm_kmalloc(int cpu) +{ + __u64 start_time; + int i; + + start_time = time_get_ns(); + for (i = 0; i < MAX_CNT; i++) + syscall(__NR_gettid); + printf("%d:lpm_perf kmalloc %lld events per sec\n", + cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time)); +} + static void loop(int cpu) { cpu_set_t cpuset; @@ -137,6 +150,9 @@ static void loop(int cpu) if (test_flags & PERCPU_LRU_HASH_PREALLOC) test_percpu_lru_hash_prealloc(cpu); + + if (test_flags & LPM_KMALLOC) + test_lpm_kmalloc(cpu); } static void run_perf_test(int tasks) @@ -162,6 +178,37 @@ static void run_perf_test(int tasks) } } +static void fill_lpm_trie(void) +{ + struct bpf_lpm_trie_key *key; + unsigned long value = 0; + unsigned int i; + int r; + + key = alloca(sizeof(*key) + 4); + key->prefixlen = 32; + + for (i = 0; i < 512; ++i) { + key->prefixlen = rand() % 33; + key->data[0] = rand() & 0xff; + key->data[1] = rand() & 0xff; + key->data[2] = rand() & 0xff; + key->data[3] = rand() & 0xff; + r = bpf_map_update_elem(map_fd[6], key, &value, 0); + assert(!r); + } + + key->prefixlen = 32; + key->data[0] = 192; + key->data[1] = 168; + key->data[2] = 0; + key->data[3] = 1; + value = 128; + + r = bpf_map_update_elem(map_fd[6], key, &value, 0); + assert(!r); +} + int main(int argc, char **argv) { struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; @@ -182,6 +229,8 @@ int main(int argc, char **argv) return 1; } + fill_lpm_trie(); + run_perf_test(num_cpu); return 0;