1 // SPDX-License-Identifier: GPL-2.0
2 /* XSKMAP used for AF_XDP sockets
3 * Copyright(c) 2018 Intel Corporation.
7 #include <linux/capability.h>
8 #include <net/xdp_sock.h>
9 #include <linux/slab.h>
10 #include <linux/sched.h>
12 int xsk_map_inc(struct xsk_map *map)
14 bpf_map_inc(&map->map);
18 void xsk_map_put(struct xsk_map *map)
20 bpf_map_put(&map->map);
23 static struct xsk_map_node *xsk_map_node_alloc(struct xsk_map *map,
24 struct xdp_sock **map_entry)
26 struct xsk_map_node *node;
29 node = kzalloc(sizeof(*node), GFP_ATOMIC | __GFP_NOWARN);
31 return ERR_PTR(-ENOMEM);
33 err = xsk_map_inc(map);
40 node->map_entry = map_entry;
44 static void xsk_map_node_free(struct xsk_map_node *node)
46 xsk_map_put(node->map);
50 static void xsk_map_sock_add(struct xdp_sock *xs, struct xsk_map_node *node)
52 spin_lock_bh(&xs->map_list_lock);
53 list_add_tail(&node->node, &xs->map_list);
54 spin_unlock_bh(&xs->map_list_lock);
57 static void xsk_map_sock_delete(struct xdp_sock *xs,
58 struct xdp_sock **map_entry)
60 struct xsk_map_node *n, *tmp;
62 spin_lock_bh(&xs->map_list_lock);
63 list_for_each_entry_safe(n, tmp, &xs->map_list, node) {
64 if (map_entry == n->map_entry) {
69 spin_unlock_bh(&xs->map_list_lock);
72 static struct bpf_map *xsk_map_alloc(union bpf_attr *attr)
74 struct bpf_map_memory mem;
75 int cpu, err, numa_node;
79 if (!capable(CAP_NET_ADMIN))
80 return ERR_PTR(-EPERM);
82 if (attr->max_entries == 0 || attr->key_size != 4 ||
83 attr->value_size != 4 ||
84 attr->map_flags & ~(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY))
85 return ERR_PTR(-EINVAL);
87 numa_node = bpf_map_attr_numa_node(attr);
88 size = struct_size(m, xsk_map, attr->max_entries);
89 cost = size + array_size(sizeof(*m->flush_list), num_possible_cpus());
91 err = bpf_map_charge_init(&mem, cost);
95 m = bpf_map_area_alloc(size, numa_node);
97 bpf_map_charge_finish(&mem);
98 return ERR_PTR(-ENOMEM);
101 bpf_map_init_from_attr(&m->map, attr);
102 bpf_map_charge_move(&m->map.memory, &mem);
103 spin_lock_init(&m->lock);
105 m->flush_list = alloc_percpu(struct list_head);
106 if (!m->flush_list) {
107 bpf_map_charge_finish(&m->map.memory);
108 bpf_map_area_free(m);
109 return ERR_PTR(-ENOMEM);
112 for_each_possible_cpu(cpu)
113 INIT_LIST_HEAD(per_cpu_ptr(m->flush_list, cpu));
118 static void xsk_map_free(struct bpf_map *map)
120 struct xsk_map *m = container_of(map, struct xsk_map, map);
122 bpf_clear_redirect_map(map);
124 free_percpu(m->flush_list);
125 bpf_map_area_free(m);
128 static int xsk_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
130 struct xsk_map *m = container_of(map, struct xsk_map, map);
131 u32 index = key ? *(u32 *)key : U32_MAX;
132 u32 *next = next_key;
134 if (index >= m->map.max_entries) {
139 if (index == m->map.max_entries - 1)
145 static u32 xsk_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
147 const int ret = BPF_REG_0, mp = BPF_REG_1, index = BPF_REG_2;
148 struct bpf_insn *insn = insn_buf;
150 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
151 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
152 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(sizeof(struct xsk_sock *)));
153 *insn++ = BPF_ALU64_IMM(BPF_ADD, mp, offsetof(struct xsk_map, xsk_map));
154 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, mp);
155 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(struct xsk_sock *), ret, ret, 0);
156 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
157 *insn++ = BPF_MOV64_IMM(ret, 0);
158 return insn - insn_buf;
161 static void *xsk_map_lookup_elem(struct bpf_map *map, void *key)
163 WARN_ON_ONCE(!rcu_read_lock_held());
164 return __xsk_map_lookup_elem(map, *(u32 *)key);
167 static void *xsk_map_lookup_elem_sys_only(struct bpf_map *map, void *key)
169 return ERR_PTR(-EOPNOTSUPP);
172 static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
175 struct xsk_map *m = container_of(map, struct xsk_map, map);
176 struct xdp_sock *xs, *old_xs, **map_entry;
177 u32 i = *(u32 *)key, fd = *(u32 *)value;
178 struct xsk_map_node *node;
182 if (unlikely(map_flags > BPF_EXIST))
184 if (unlikely(i >= m->map.max_entries))
187 sock = sockfd_lookup(fd, &err);
191 if (sock->sk->sk_family != PF_XDP) {
196 xs = (struct xdp_sock *)sock->sk;
198 if (!xsk_is_setup_for_bpf_map(xs)) {
203 map_entry = &m->xsk_map[i];
204 node = xsk_map_node_alloc(m, map_entry);
207 return PTR_ERR(node);
210 spin_lock_bh(&m->lock);
211 old_xs = READ_ONCE(*map_entry);
215 } else if (old_xs && map_flags == BPF_NOEXIST) {
218 } else if (!old_xs && map_flags == BPF_EXIST) {
222 xsk_map_sock_add(xs, node);
223 WRITE_ONCE(*map_entry, xs);
225 xsk_map_sock_delete(old_xs, map_entry);
226 spin_unlock_bh(&m->lock);
231 spin_unlock_bh(&m->lock);
233 xsk_map_node_free(node);
237 static int xsk_map_delete_elem(struct bpf_map *map, void *key)
239 struct xsk_map *m = container_of(map, struct xsk_map, map);
240 struct xdp_sock *old_xs, **map_entry;
243 if (k >= map->max_entries)
246 spin_lock_bh(&m->lock);
247 map_entry = &m->xsk_map[k];
248 old_xs = xchg(map_entry, NULL);
250 xsk_map_sock_delete(old_xs, map_entry);
251 spin_unlock_bh(&m->lock);
256 void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs,
257 struct xdp_sock **map_entry)
259 spin_lock_bh(&map->lock);
260 if (READ_ONCE(*map_entry) == xs) {
261 WRITE_ONCE(*map_entry, NULL);
262 xsk_map_sock_delete(xs, map_entry);
264 spin_unlock_bh(&map->lock);
267 const struct bpf_map_ops xsk_map_ops = {
268 .map_alloc = xsk_map_alloc,
269 .map_free = xsk_map_free,
270 .map_get_next_key = xsk_map_get_next_key,
271 .map_lookup_elem = xsk_map_lookup_elem,
272 .map_gen_lookup = xsk_map_gen_lookup,
273 .map_lookup_elem_sys_only = xsk_map_lookup_elem_sys_only,
274 .map_update_elem = xsk_map_update_elem,
275 .map_delete_elem = xsk_map_delete_elem,
276 .map_check_btf = map_check_no_btf,