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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /net/xdp/xskmap.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/xdp/xskmap.c')
-rw-r--r-- | net/xdp/xskmap.c | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c new file mode 100644 index 000000000..acc8e52a4 --- /dev/null +++ b/net/xdp/xskmap.c @@ -0,0 +1,272 @@ +// SPDX-License-Identifier: GPL-2.0 +/* XSKMAP used for AF_XDP sockets + * Copyright(c) 2018 Intel Corporation. + */ + +#include <linux/bpf.h> +#include <linux/filter.h> +#include <linux/capability.h> +#include <net/xdp_sock.h> +#include <linux/slab.h> +#include <linux/sched.h> +#include <linux/btf_ids.h> + +#include "xsk.h" + +static struct xsk_map_node *xsk_map_node_alloc(struct xsk_map *map, + struct xdp_sock __rcu **map_entry) +{ + struct xsk_map_node *node; + + node = bpf_map_kzalloc(&map->map, sizeof(*node), + GFP_ATOMIC | __GFP_NOWARN); + if (!node) + return ERR_PTR(-ENOMEM); + + bpf_map_inc(&map->map); + + node->map = map; + node->map_entry = map_entry; + return node; +} + +static void xsk_map_node_free(struct xsk_map_node *node) +{ + bpf_map_put(&node->map->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 __rcu **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 xsk_map *m; + int numa_node; + 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); + + m = bpf_map_area_alloc(size, numa_node); + if (!m) + return ERR_PTR(-ENOMEM); + + bpf_map_init_from_attr(&m->map, attr); + 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); + + 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 int 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; +} + +/* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or + * by local_bh_disable() (from XDP calls inside NAPI). The + * rcu_read_lock_bh_held() below makes lockdep accept both. + */ +static void *__xsk_map_lookup_elem(struct bpf_map *map, u32 key) +{ + struct xsk_map *m = container_of(map, struct xsk_map, map); + + if (key >= map->max_entries) + return NULL; + + return rcu_dereference_check(m->xsk_map[key], rcu_read_lock_bh_held()); +} + +static void *xsk_map_lookup_elem(struct bpf_map *map, void *key) +{ + 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 __rcu **map_entry; + struct xdp_sock *xs, *old_xs; + 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; + + 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 = rcu_dereference_protected(*map_entry, lockdep_is_held(&m->lock)); + 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); + rcu_assign_pointer(*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 __rcu **map_entry; + struct xdp_sock *old_xs; + int k = *(u32 *)key; + + if (k >= map->max_entries) + return -EINVAL; + + spin_lock_bh(&m->lock); + map_entry = &m->xsk_map[k]; + old_xs = unrcu_pointer(xchg(map_entry, NULL)); + if (old_xs) + xsk_map_sock_delete(old_xs, map_entry); + spin_unlock_bh(&m->lock); + + return 0; +} + +static int xsk_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags) +{ + return __bpf_xdp_redirect_map(map, ifindex, flags, 0, + __xsk_map_lookup_elem); +} + +void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs, + struct xdp_sock __rcu **map_entry) +{ + spin_lock_bh(&map->lock); + if (rcu_access_pointer(*map_entry) == xs) { + rcu_assign_pointer(*map_entry, NULL); + xsk_map_sock_delete(xs, map_entry); + } + spin_unlock_bh(&map->lock); +} + +static bool xsk_map_meta_equal(const struct bpf_map *meta0, + const struct bpf_map *meta1) +{ + return meta0->max_entries == meta1->max_entries && + bpf_map_meta_equal(meta0, meta1); +} + +BTF_ID_LIST_SINGLE(xsk_map_btf_ids, struct, xsk_map) +const struct bpf_map_ops xsk_map_ops = { + .map_meta_equal = xsk_map_meta_equal, + .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, + .map_btf_id = &xsk_map_btf_ids[0], + .map_redirect = xsk_map_redirect, +}; |