From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mauricio Vasquez B Subject: [RFC PATCH bpf-next v3 4/7] bpf: add bpf queue and stack maps Date: Tue, 18 Sep 2018 06:52:51 +0200 Message-ID: <153724637114.7866.8418882266337744689.stgit@kernel> References: <153724634652.7866.6354309647800281793.stgit@kernel> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Yonghong Song To: Alexei Starovoitov , Daniel Borkmann , netdev@vger.kernel.org Return-path: Received: from fm1nodo1.polito.it ([130.192.180.16]:44164 "EHLO antispam.polito.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726779AbeIRKYJ (ORCPT ); Tue, 18 Sep 2018 06:24:09 -0400 In-Reply-To: <153724634652.7866.6354309647800281793.stgit@kernel> Sender: netdev-owner@vger.kernel.org List-ID: Implement two new kind of maps that support the peek, push and pop operations. A use case for this is to keep track of a pool of elements, like network ports in a SNAT. Signed-off-by: Mauricio Vasquez B --- include/linux/bpf.h | 3 include/linux/bpf_types.h | 2 include/uapi/linux/bpf.h | 30 ++++ kernel/bpf/Makefile | 2 kernel/bpf/core.c | 3 kernel/bpf/helpers.c | 98 ++++++++++++++ kernel/bpf/queue_stack_maps.c | 291 +++++++++++++++++++++++++++++++++++++++++ kernel/bpf/verifier.c | 5 + net/core/filter.c | 6 + 9 files changed, 437 insertions(+), 3 deletions(-) create mode 100644 kernel/bpf/queue_stack_maps.c diff --git a/include/linux/bpf.h b/include/linux/bpf.h index c63a44381d3f..8e924b5c5a0e 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -807,6 +807,9 @@ static inline int bpf_fd_reuseport_array_update_elem(struct bpf_map *map, extern const struct bpf_func_proto bpf_map_lookup_elem_proto; extern const struct bpf_func_proto bpf_map_update_elem_proto; extern const struct bpf_func_proto bpf_map_delete_elem_proto; +extern const struct bpf_func_proto bpf_map_push_elem_proto; +extern const struct bpf_func_proto bpf_map_pop_elem_proto; +extern const struct bpf_func_proto bpf_map_peek_elem_proto; extern const struct bpf_func_proto bpf_get_prandom_u32_proto; extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 33f7f574b983..903a446f14c3 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -67,3 +67,5 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_XSKMAP, xsk_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, reuseport_array_ops) #endif #endif +BPF_MAP_TYPE(BPF_MAP_TYPE_QUEUE, queue_map_ops) +BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 4cda584c6640..c899386dcb2b 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -128,6 +128,8 @@ enum bpf_map_type { BPF_MAP_TYPE_SOCKHASH, BPF_MAP_TYPE_CGROUP_STORAGE, BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, + BPF_MAP_TYPE_QUEUE, + BPF_MAP_TYPE_STACK, }; enum bpf_prog_type { @@ -460,6 +462,29 @@ union bpf_attr { * Return * 0 on success, or a negative error in case of failure. * + * int bpf_map_push_elem(struct bpf_map *map, const void *value, u32 len, + * u64 flags) + * Description + * Push an element *value* in *map*. *flags* is one of: + * + * **BPF_EXIST** + * If the queue/stack is full, the oldest element is removed to + * make room for this. + * Return + * 0 on success, or a negative error in case of failure. + * + * int bpf_map_pop_elem(struct bpf_map *map, void *value, u32 len) + * Description + * Pop an element from *map*. + * Return + * 0 on success, or a negative error in case of failure. + * + * int bpf_map_peek_elem(struct bpf_map *map, void *value, u32 len) + * Description + * Get an element from *map* without removing it. + * Return + * 0 on success, or a negative error in case of failure. + * * int bpf_probe_read(void *dst, u32 size, const void *src) * Description * For tracing programs, safely attempt to read *size* bytes from @@ -2227,7 +2252,10 @@ union bpf_attr { FN(get_current_cgroup_id), \ FN(get_local_storage), \ FN(sk_select_reuseport), \ - FN(skb_ancestor_cgroup_id), + FN(skb_ancestor_cgroup_id), \ + FN(map_push_elem), \ + FN(map_pop_elem), \ + FN(map_peek_elem), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index e656bce87c8f..2d77bc5b2aca 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -3,7 +3,7 @@ obj-y := core.o obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o -obj-$(CONFIG_BPF_SYSCALL) += local_storage.o +obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o obj-$(CONFIG_BPF_SYSCALL) += disasm.o obj-$(CONFIG_BPF_SYSCALL) += btf.o ifeq ($(CONFIG_NET),y) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 3f5bf1af0826..8d2db076d123 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1783,6 +1783,9 @@ BPF_CALL_0(bpf_user_rnd_u32) const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; const struct bpf_func_proto bpf_map_update_elem_proto __weak; const struct bpf_func_proto bpf_map_delete_elem_proto __weak; +const struct bpf_func_proto bpf_map_push_elem_proto __weak; +const struct bpf_func_proto bpf_map_pop_elem_proto __weak; +const struct bpf_func_proto bpf_map_peek_elem_proto __weak; const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 1991466b8327..5f364e6acaf1 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -76,6 +76,104 @@ const struct bpf_func_proto bpf_map_delete_elem_proto = { .arg2_type = ARG_PTR_TO_MAP_KEY, }; +BPF_CALL_4(bpf_map_push_elem, struct bpf_map *, map, void *, value, u32 size, + u64, flags) +{ + if (map->value_size != size) + return -EINVAL; + + return map->ops->map_update_elem(map, NULL, value, flags); +} + +const struct bpf_func_proto bpf_map_push_elem_proto = { + .func = bpf_map_push_elem, + .gpl_only = false, + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, + .arg4_type = ARG_ANYTHING, +}; + +BPF_CALL_3(bpf_map_pop_elem, struct bpf_map *, map, void *, value, u32, size) +{ + void *ptr; + + if (map->value_size != size) + return -EINVAL; + + ptr = map->ops->map_lookup_and_delete_elem(map, NULL); + if (!ptr) + return -ENOENT; + + switch (size) { + case 1: + *(u8 *) value = *(u8 *) ptr; + break; + case 2: + *(u16 *) value = *(u16 *) ptr; + break; + case 4: + *(u32 *) value = *(u32 *) ptr; + break; + case 8: + *(u64 *) value = *(u64 *) ptr; + break; + } + + return 0; +} + +const struct bpf_func_proto bpf_map_pop_elem_proto = { + .func = bpf_map_pop_elem, + .gpl_only = false, + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_UNINIT_MEM, + .arg3_type = ARG_CONST_SIZE, +}; + +BPF_CALL_3(bpf_map_peek_elem, struct bpf_map *, map, void *, value, u32, size) +{ + void *ptr; + + if (map->value_size != size) + return -EINVAL; + + ptr = map->ops->map_lookup_elem(map, NULL); + if (!ptr) + return -ENOENT; + + switch (size) { + case 1: + *(u8 *) value = *(u8 *) ptr; + break; + case 2: + *(u16 *) value = *(u16 *) ptr; + break; + case 4: + *(u32 *) value = *(u32 *) ptr; + break; + case 8: + *(u64 *) value = *(u64 *) ptr; + break; + } + + return 0; +} + +const struct bpf_func_proto bpf_map_peek_elem_proto = { + .func = bpf_map_pop_elem, + .gpl_only = false, + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_UNINIT_MEM, + .arg3_type = ARG_CONST_SIZE, +}; + const struct bpf_func_proto bpf_get_prandom_u32_proto = { .func = bpf_user_rnd_u32, .gpl_only = false, diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c new file mode 100644 index 000000000000..10c081f3f02b --- /dev/null +++ b/kernel/bpf/queue_stack_maps.c @@ -0,0 +1,291 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * queue_stack_maps.c: BPF queue and stack maps + * + * Copyright (c) 2018 Politecnico di Torino + */ +#include +#include +#include +#include "percpu_freelist.h" + +#define QUEUE_STACK_CREATE_FLAG_MASK \ + (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY) + + +struct bpf_queue_stack { + struct bpf_map map; + raw_spinlock_t lock; + u32 head, tail; + u32 index_mask; + u32 count; + + char elements[0] __aligned(8); +}; + +static struct bpf_queue_stack *bpf_queue_stack(struct bpf_map *map) +{ + return container_of(map, struct bpf_queue_stack, map); +} + +static bool queue_stack_map_is_empty(struct bpf_queue_stack *qs) +{ + return qs->count == 0; +} + +static bool queue_stack_map_is_full(struct bpf_queue_stack *qs) +{ + return qs->count == qs->map.max_entries; +} + +/* Called from syscall */ +static int queue_stack_map_alloc_check(union bpf_attr *attr) +{ + /* check sanity of attributes */ + if (attr->max_entries == 0 || attr->key_size != 0 || + (attr->value_size != 1 && attr->value_size != 2 && + attr->value_size != 4 && attr->value_size != 8) || + attr->map_flags & ~QUEUE_STACK_CREATE_FLAG_MASK) + return -EINVAL; + + if (attr->value_size > KMALLOC_MAX_SIZE) + /* if value_size is bigger, the user space won't be able to + * access the elements. + */ + return -E2BIG; + + return 0; +} + +static struct bpf_map *queue_stack_map_alloc(union bpf_attr *attr) +{ + int ret, numa_node = bpf_map_attr_numa_node(attr); + u32 max_entries, value_size, index_mask; + u64 queue_size, cost, mask64; + struct bpf_queue_stack *qs; + + max_entries = attr->max_entries; + value_size = attr->value_size; + + /* From arraymap.c: + * On 32 bit archs roundup_pow_of_two() with max_entries that has + * upper most bit set in u32 space is undefined behavior due to + * resulting 1U << 32, so do it manually here in u64 space. + */ + mask64 = fls_long(max_entries - 1); + mask64 = 1ULL << mask64; + mask64 -= 1; + + index_mask = mask64; + + /* Round up queue size to nearest power of 2 */ + max_entries = index_mask + 1; + /* Check for overflows. */ + if (max_entries < attr->max_entries) + return ERR_PTR(-E2BIG); + + queue_size = sizeof(*qs) + (u64) value_size * max_entries; + + cost = queue_size; + if (cost >= U32_MAX - PAGE_SIZE) + return ERR_PTR(-E2BIG); + + cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; + + ret = bpf_map_precharge_memlock(cost); + if (ret < 0) + return ERR_PTR(ret); + + qs = bpf_map_area_alloc(queue_size, numa_node); + if (!qs) + return ERR_PTR(-ENOMEM); + + memset(qs, 0, sizeof(*qs)); + + bpf_map_init_from_attr(&qs->map, attr); + + qs->map.pages = cost; + qs->index_mask = index_mask; + + raw_spin_lock_init(&qs->lock); + + return &qs->map; +} + +/* Called when map->refcnt goes to zero, either from workqueue or from syscall */ +static void queue_stack_map_free(struct bpf_map *map) +{ + struct bpf_queue_stack *qs = bpf_queue_stack(map); + + /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, + * so the programs (can be more than one that used this map) were + * disconnected from events. Wait for outstanding critical sections in + * these programs to complete + */ + synchronize_rcu(); + + bpf_map_area_free(qs); +} + +static void *__queue_map_lookup(struct bpf_map *map, bool delete) +{ + struct bpf_queue_stack *qs = bpf_queue_stack(map); + unsigned long flags; + void *ptr = NULL; + + raw_spin_lock_irqsave(&qs->lock, flags); + + if (queue_stack_map_is_empty(qs)) + goto out; + + ptr = &qs->elements[qs->tail * qs->map.value_size]; + + if (delete) { + qs->tail = (qs->tail + 1) & qs->index_mask; + qs->count--; + } + +out: + raw_spin_unlock_irqrestore(&qs->lock, flags); + return ptr; +} + + +static void *__stack_map_lookup(struct bpf_map *map, bool delete) +{ + struct bpf_queue_stack *qs = bpf_queue_stack(map); + unsigned long flags; + void *ptr = NULL; + u32 index; + + raw_spin_lock_irqsave(&qs->lock, flags); + + if (queue_stack_map_is_empty(qs)) + goto out; + + index = (qs->head - 1) & qs->index_mask; + ptr = &qs->elements[index * qs->map.value_size]; + + if (delete) { + qs->head = (qs->head - 1) & qs->index_mask; + qs->count--; + } + +out: + raw_spin_unlock_irqrestore(&qs->lock, flags); + return ptr; +} + +/* Called from syscall or from eBPF program */ +static void *queue_map_lookup_elem(struct bpf_map *map, void *key) +{ + return __queue_map_lookup(map, false); +} + +/* Called from syscall or from eBPF program */ +static void *stack_map_lookup_elem(struct bpf_map *map, void *key) +{ + return __stack_map_lookup(map, false); +} + +/* Called from syscall or from eBPF program */ +static void *queue_map_lookup_and_delete_elem(struct bpf_map *map, void *key) +{ + return __queue_map_lookup(map, true); +} + +/* Called from syscall or from eBPF program */ +static void *stack_map_lookup_and_delete_elem(struct bpf_map *map, void *key) +{ + return __stack_map_lookup(map, true); +} + +/* Called from syscall or from eBPF program */ +static int queue_stack_map_update_elem(struct bpf_map *map, void *key, + void *value, u64 flags) +{ + struct bpf_queue_stack *qs = bpf_queue_stack(map); + unsigned long irq_flags; + int err = 0; + void *dst; + + /* BPF_EXIST is used to force making room for a new element in case the + * map is full + */ + bool replace = (flags & BPF_EXIST); + + /* Check supported flags for queue and stqueue_map_is_preallocack maps */ + if (flags & BPF_NOEXIST || flags > BPF_EXIST) + return -EINVAL; + + raw_spin_lock_irqsave(&qs->lock, irq_flags); + + if (queue_stack_map_is_full(qs)) { + if (!replace) { + err = -E2BIG; + goto out; + } + /* advance tail pointer to overwrite oldest element */ + qs->tail = (qs->tail + 1) & qs->index_mask; + qs->count--; + } + + dst = &qs->elements[qs->head * qs->map.value_size]; + + switch (qs->map.value_size) { + case 1: + *(u8 *) dst = *(u8 *) value; + break; + case 2: + *(u16 *) dst = *(u16 *) value; + break; + case 4: + *(u32 *) dst = *(u32 *) value; + break; + case 8: + *(u64 *) dst = *(u64 *) value; + break; + } + + qs->head = (qs->head + 1) & qs->index_mask; + qs->count++; + +out: + raw_spin_unlock_irqrestore(&qs->lock, irq_flags); + return err; +} + +/* Called from syscall or from eBPF program */ +static int queue_stack_map_delete_elem(struct bpf_map *map, void *key) +{ + return -EINVAL; +} + +/* Called from syscall */ +static int queue_stack_map_get_next_key(struct bpf_map *map, void *key, + void *next_key) +{ + return -EINVAL; +} + +const struct bpf_map_ops queue_map_ops = { + .map_alloc_check = queue_stack_map_alloc_check, + .map_alloc = queue_stack_map_alloc, + .map_free = queue_stack_map_free, + .map_lookup_elem = queue_map_lookup_elem, + .map_lookup_and_delete_elem = queue_map_lookup_and_delete_elem, + .map_update_elem = queue_stack_map_update_elem, + .map_delete_elem = queue_stack_map_delete_elem, + .map_get_next_key = queue_stack_map_get_next_key, +}; + +const struct bpf_map_ops stack_map_ops = { + .map_alloc_check = queue_stack_map_alloc_check, + .map_alloc = queue_stack_map_alloc, + .map_free = queue_stack_map_free, + .map_lookup_elem = stack_map_lookup_elem, + .map_lookup_and_delete_elem = stack_map_lookup_and_delete_elem, + .map_update_elem = queue_stack_map_update_elem, + .map_delete_elem = queue_stack_map_delete_elem, + .map_get_next_key = queue_stack_map_get_next_key, +}; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index f4ff0c569e54..b9e005188f0e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2369,7 +2369,10 @@ record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, if (func_id != BPF_FUNC_tail_call && func_id != BPF_FUNC_map_lookup_elem && func_id != BPF_FUNC_map_update_elem && - func_id != BPF_FUNC_map_delete_elem) + func_id != BPF_FUNC_map_delete_elem && + func_id != BPF_FUNC_map_push_elem && + func_id != BPF_FUNC_map_pop_elem && + func_id != BPF_FUNC_map_peek_elem) return 0; if (meta->map_ptr == NULL) { diff --git a/net/core/filter.c b/net/core/filter.c index feb578506009..c7b73376c23a 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4839,6 +4839,12 @@ bpf_base_func_proto(enum bpf_func_id func_id) return &bpf_map_update_elem_proto; case BPF_FUNC_map_delete_elem: return &bpf_map_delete_elem_proto; + case BPF_FUNC_map_push_elem: + return &bpf_map_push_elem_proto; + case BPF_FUNC_map_pop_elem: + return &bpf_map_pop_elem_proto; + case BPF_FUNC_map_peek_elem: + return &bpf_map_peek_elem_proto; case BPF_FUNC_get_prandom_u32: return &bpf_get_prandom_u32_proto; case BPF_FUNC_get_smp_processor_id: