diff options
Diffstat (limited to 'net/xdp')
-rw-r--r-- | net/xdp/Makefile | 2 | ||||
-rw-r--r-- | net/xdp/xsk.h | 16 | ||||
-rw-r--r-- | net/xdp/xskmap.c | 267 |
3 files changed, 284 insertions, 1 deletions
diff --git a/net/xdp/Makefile b/net/xdp/Makefile index 71e2bdafb2ce..90b5460d6166 100644 --- a/net/xdp/Makefile +++ b/net/xdp/Makefile @@ -1,3 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only -obj-$(CONFIG_XDP_SOCKETS) += xsk.o xdp_umem.o xsk_queue.o +obj-$(CONFIG_XDP_SOCKETS) += xsk.o xdp_umem.o xsk_queue.o xskmap.o obj-$(CONFIG_XDP_SOCKETS_DIAG) += xsk_diag.o diff --git a/net/xdp/xsk.h b/net/xdp/xsk.h index 4cfd106bdb53..d6a0979050e6 100644 --- a/net/xdp/xsk.h +++ b/net/xdp/xsk.h @@ -17,9 +17,25 @@ struct xdp_mmap_offsets_v1 { struct xdp_ring_offset_v1 cr; }; +/* Nodes are linked in the struct xdp_sock map_list field, and used to + * track which maps a certain socket reside in. + */ + +struct xsk_map_node { + struct list_head node; + struct xsk_map *map; + struct xdp_sock **map_entry; +}; + static inline struct xdp_sock *xdp_sk(struct sock *sk) { return (struct xdp_sock *)sk; } +bool xsk_is_setup_for_bpf_map(struct xdp_sock *xs); +void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs, + struct xdp_sock **map_entry); +int xsk_map_inc(struct xsk_map *map); +void xsk_map_put(struct xsk_map *map); + #endif /* XSK_H_ */ diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c new file mode 100644 index 000000000000..1dc7208c71ba --- /dev/null +++ b/net/xdp/xskmap.c @@ -0,0 +1,267 @@ +// SPDX-License-Identifier: GPL-2.0 +/* XSKMAP used for AF_XDP sockets + * Copyright(c) 2018 Intel Corporation. + */ + +#include <linux/bpf.h> +#include <linux/capability.h> +#include <net/xdp_sock.h> +#include <linux/slab.h> +#include <linux/sched.h> + +#include "xsk.h" + +int xsk_map_inc(struct xsk_map *map) +{ + bpf_map_inc(&map->map); + return 0; +} + +void xsk_map_put(struct xsk_map *map) +{ + bpf_map_put(&map->map); +} + +static struct xsk_map_node *xsk_map_node_alloc(struct xsk_map *map, + struct xdp_sock **map_entry) +{ + struct xsk_map_node *node; + int err; + + node = kzalloc(sizeof(*node), GFP_ATOMIC | __GFP_NOWARN); + if (!node) + return ERR_PTR(-ENOMEM); + + err = xsk_map_inc(map); + if (err) { + kfree(node); + return ERR_PTR(err); + } + + node->map = map; + node->map_entry = map_entry; + return node; +} + +static void xsk_map_node_free(struct xsk_map_node *node) +{ + xsk_map_put(node->map); + kfree(node); +} + +static void xsk_map_sock_add(struct xdp_sock *xs, struct xsk_map_node *node) +{ + spin_lock_bh(&xs->map_list_lock); + list_add_tail(&node->node, &xs->map_list); + spin_unlock_bh(&xs->map_list_lock); +} + +static void xsk_map_sock_delete(struct xdp_sock *xs, + struct xdp_sock **map_entry) +{ + struct xsk_map_node *n, *tmp; + + spin_lock_bh(&xs->map_list_lock); + list_for_each_entry_safe(n, tmp, &xs->map_list, node) { + if (map_entry == n->map_entry) { + list_del(&n->node); + xsk_map_node_free(n); + } + } + spin_unlock_bh(&xs->map_list_lock); +} + +static struct bpf_map *xsk_map_alloc(union bpf_attr *attr) +{ + struct bpf_map_memory mem; + int err, numa_node; + struct xsk_map *m; + u64 size; + + if (!capable(CAP_NET_ADMIN)) + return ERR_PTR(-EPERM); + + if (attr->max_entries == 0 || attr->key_size != 4 || + attr->value_size != 4 || + attr->map_flags & ~(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)) + return ERR_PTR(-EINVAL); + + numa_node = bpf_map_attr_numa_node(attr); + size = struct_size(m, xsk_map, attr->max_entries); + + err = bpf_map_charge_init(&mem, size); + if (err < 0) + return ERR_PTR(err); + + m = bpf_map_area_alloc(size, numa_node); + if (!m) { + bpf_map_charge_finish(&mem); + return ERR_PTR(-ENOMEM); + } + + bpf_map_init_from_attr(&m->map, attr); + bpf_map_charge_move(&m->map.memory, &mem); + spin_lock_init(&m->lock); + + return &m->map; +} + +static void xsk_map_free(struct bpf_map *map) +{ + struct xsk_map *m = container_of(map, struct xsk_map, map); + + bpf_clear_redirect_map(map); + synchronize_net(); + bpf_map_area_free(m); +} + +static int xsk_map_get_next_key(struct bpf_map *map, void *key, void *next_key) +{ + struct xsk_map *m = container_of(map, struct xsk_map, map); + u32 index = key ? *(u32 *)key : U32_MAX; + u32 *next = next_key; + + if (index >= m->map.max_entries) { + *next = 0; + return 0; + } + + if (index == m->map.max_entries - 1) + return -ENOENT; + *next = index + 1; + return 0; +} + +static u32 xsk_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf) +{ + const int ret = BPF_REG_0, mp = BPF_REG_1, index = BPF_REG_2; + struct bpf_insn *insn = insn_buf; + + *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0); + *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5); + *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(sizeof(struct xsk_sock *))); + *insn++ = BPF_ALU64_IMM(BPF_ADD, mp, offsetof(struct xsk_map, xsk_map)); + *insn++ = BPF_ALU64_REG(BPF_ADD, ret, mp); + *insn++ = BPF_LDX_MEM(BPF_SIZEOF(struct xsk_sock *), ret, ret, 0); + *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); + *insn++ = BPF_MOV64_IMM(ret, 0); + return insn - insn_buf; +} + +static void *xsk_map_lookup_elem(struct bpf_map *map, void *key) +{ + WARN_ON_ONCE(!rcu_read_lock_held()); + return __xsk_map_lookup_elem(map, *(u32 *)key); +} + +static void *xsk_map_lookup_elem_sys_only(struct bpf_map *map, void *key) +{ + return ERR_PTR(-EOPNOTSUPP); +} + +static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value, + u64 map_flags) +{ + struct xsk_map *m = container_of(map, struct xsk_map, map); + struct xdp_sock *xs, *old_xs, **map_entry; + u32 i = *(u32 *)key, fd = *(u32 *)value; + struct xsk_map_node *node; + struct socket *sock; + int err; + + if (unlikely(map_flags > BPF_EXIST)) + return -EINVAL; + if (unlikely(i >= m->map.max_entries)) + return -E2BIG; + + sock = sockfd_lookup(fd, &err); + if (!sock) + return err; + + if (sock->sk->sk_family != PF_XDP) { + sockfd_put(sock); + return -EOPNOTSUPP; + } + + xs = (struct xdp_sock *)sock->sk; + + if (!xsk_is_setup_for_bpf_map(xs)) { + sockfd_put(sock); + return -EOPNOTSUPP; + } + + map_entry = &m->xsk_map[i]; + node = xsk_map_node_alloc(m, map_entry); + if (IS_ERR(node)) { + sockfd_put(sock); + return PTR_ERR(node); + } + + spin_lock_bh(&m->lock); + old_xs = READ_ONCE(*map_entry); + if (old_xs == xs) { + err = 0; + goto out; + } else if (old_xs && map_flags == BPF_NOEXIST) { + err = -EEXIST; + goto out; + } else if (!old_xs && map_flags == BPF_EXIST) { + err = -ENOENT; + goto out; + } + xsk_map_sock_add(xs, node); + WRITE_ONCE(*map_entry, xs); + if (old_xs) + xsk_map_sock_delete(old_xs, map_entry); + spin_unlock_bh(&m->lock); + sockfd_put(sock); + return 0; + +out: + spin_unlock_bh(&m->lock); + sockfd_put(sock); + xsk_map_node_free(node); + return err; +} + +static int xsk_map_delete_elem(struct bpf_map *map, void *key) +{ + struct xsk_map *m = container_of(map, struct xsk_map, map); + struct xdp_sock *old_xs, **map_entry; + int k = *(u32 *)key; + + if (k >= map->max_entries) + return -EINVAL; + + spin_lock_bh(&m->lock); + map_entry = &m->xsk_map[k]; + old_xs = xchg(map_entry, NULL); + if (old_xs) + xsk_map_sock_delete(old_xs, map_entry); + spin_unlock_bh(&m->lock); + + return 0; +} + +void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs, + struct xdp_sock **map_entry) +{ + spin_lock_bh(&map->lock); + if (READ_ONCE(*map_entry) == xs) { + WRITE_ONCE(*map_entry, NULL); + xsk_map_sock_delete(xs, map_entry); + } + spin_unlock_bh(&map->lock); +} + +const struct bpf_map_ops xsk_map_ops = { + .map_alloc = xsk_map_alloc, + .map_free = xsk_map_free, + .map_get_next_key = xsk_map_get_next_key, + .map_lookup_elem = xsk_map_lookup_elem, + .map_gen_lookup = xsk_map_gen_lookup, + .map_lookup_elem_sys_only = xsk_map_lookup_elem_sys_only, + .map_update_elem = xsk_map_update_elem, + .map_delete_elem = xsk_map_delete_elem, + .map_check_btf = map_check_no_btf, +}; |