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>
14 int xsk_map_inc(struct xsk_map *map)
16 bpf_map_inc(&map->map);
20 void xsk_map_put(struct xsk_map *map)
22 bpf_map_put(&map->map);
25 static struct xsk_map_node *xsk_map_node_alloc(struct xsk_map *map,
26 struct xdp_sock **map_entry)
28 struct xsk_map_node *node;
31 node = kzalloc(sizeof(*node), GFP_ATOMIC | __GFP_NOWARN);
33 return ERR_PTR(-ENOMEM);
35 err = xsk_map_inc(map);
42 node->map_entry = map_entry;
46 static void xsk_map_node_free(struct xsk_map_node *node)
48 xsk_map_put(node->map);
52 static void xsk_map_sock_add(struct xdp_sock *xs, struct xsk_map_node *node)
54 spin_lock_bh(&xs->map_list_lock);
55 list_add_tail(&node->node, &xs->map_list);
56 spin_unlock_bh(&xs->map_list_lock);
59 static void xsk_map_sock_delete(struct xdp_sock *xs,
60 struct xdp_sock **map_entry)
62 struct xsk_map_node *n, *tmp;
64 spin_lock_bh(&xs->map_list_lock);
65 list_for_each_entry_safe(n, tmp, &xs->map_list, node) {
66 if (map_entry == n->map_entry) {
71 spin_unlock_bh(&xs->map_list_lock);
74 static struct bpf_map *xsk_map_alloc(union bpf_attr *attr)
76 struct bpf_map_memory mem;
81 if (!capable(CAP_NET_ADMIN))
82 return ERR_PTR(-EPERM);
84 if (attr->max_entries == 0 || attr->key_size != 4 ||
85 attr->value_size != 4 ||
86 attr->map_flags & ~(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY))
87 return ERR_PTR(-EINVAL);
89 numa_node = bpf_map_attr_numa_node(attr);
90 size = struct_size(m, xsk_map, attr->max_entries);
92 err = bpf_map_charge_init(&mem, size);
96 m = bpf_map_area_alloc(size, numa_node);
98 bpf_map_charge_finish(&mem);
99 return ERR_PTR(-ENOMEM);
102 bpf_map_init_from_attr(&m->map, attr);
103 bpf_map_charge_move(&m->map.memory, &mem);
104 spin_lock_init(&m->lock);
109 static void xsk_map_free(struct bpf_map *map)
111 struct xsk_map *m = container_of(map, struct xsk_map, map);
113 bpf_clear_redirect_map(map);
115 bpf_map_area_free(m);
118 static int xsk_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
120 struct xsk_map *m = container_of(map, struct xsk_map, map);
121 u32 index = key ? *(u32 *)key : U32_MAX;
122 u32 *next = next_key;
124 if (index >= m->map.max_entries) {
129 if (index == m->map.max_entries - 1)
135 static int xsk_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
137 const int ret = BPF_REG_0, mp = BPF_REG_1, index = BPF_REG_2;
138 struct bpf_insn *insn = insn_buf;
140 *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
141 *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
142 *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(sizeof(struct xsk_sock *)));
143 *insn++ = BPF_ALU64_IMM(BPF_ADD, mp, offsetof(struct xsk_map, xsk_map));
144 *insn++ = BPF_ALU64_REG(BPF_ADD, ret, mp);
145 *insn++ = BPF_LDX_MEM(BPF_SIZEOF(struct xsk_sock *), ret, ret, 0);
146 *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
147 *insn++ = BPF_MOV64_IMM(ret, 0);
148 return insn - insn_buf;
151 static void *xsk_map_lookup_elem(struct bpf_map *map, void *key)
153 WARN_ON_ONCE(!rcu_read_lock_held());
154 return __xsk_map_lookup_elem(map, *(u32 *)key);
157 static void *xsk_map_lookup_elem_sys_only(struct bpf_map *map, void *key)
159 return ERR_PTR(-EOPNOTSUPP);
162 static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
165 struct xsk_map *m = container_of(map, struct xsk_map, map);
166 struct xdp_sock *xs, *old_xs, **map_entry;
167 u32 i = *(u32 *)key, fd = *(u32 *)value;
168 struct xsk_map_node *node;
172 if (unlikely(map_flags > BPF_EXIST))
174 if (unlikely(i >= m->map.max_entries))
177 sock = sockfd_lookup(fd, &err);
181 if (sock->sk->sk_family != PF_XDP) {
186 xs = (struct xdp_sock *)sock->sk;
188 map_entry = &m->xsk_map[i];
189 node = xsk_map_node_alloc(m, map_entry);
192 return PTR_ERR(node);
195 spin_lock_bh(&m->lock);
196 old_xs = READ_ONCE(*map_entry);
200 } else if (old_xs && map_flags == BPF_NOEXIST) {
203 } else if (!old_xs && map_flags == BPF_EXIST) {
207 xsk_map_sock_add(xs, node);
208 WRITE_ONCE(*map_entry, xs);
210 xsk_map_sock_delete(old_xs, map_entry);
211 spin_unlock_bh(&m->lock);
216 spin_unlock_bh(&m->lock);
218 xsk_map_node_free(node);
222 static int xsk_map_delete_elem(struct bpf_map *map, void *key)
224 struct xsk_map *m = container_of(map, struct xsk_map, map);
225 struct xdp_sock *old_xs, **map_entry;
228 if (k >= map->max_entries)
231 spin_lock_bh(&m->lock);
232 map_entry = &m->xsk_map[k];
233 old_xs = xchg(map_entry, NULL);
235 xsk_map_sock_delete(old_xs, map_entry);
236 spin_unlock_bh(&m->lock);
241 void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs,
242 struct xdp_sock **map_entry)
244 spin_lock_bh(&map->lock);
245 if (READ_ONCE(*map_entry) == xs) {
246 WRITE_ONCE(*map_entry, NULL);
247 xsk_map_sock_delete(xs, map_entry);
249 spin_unlock_bh(&map->lock);
252 static bool xsk_map_meta_equal(const struct bpf_map *meta0,
253 const struct bpf_map *meta1)
255 return meta0->max_entries == meta1->max_entries &&
256 bpf_map_meta_equal(meta0, meta1);
259 static int xsk_map_btf_id;
260 const struct bpf_map_ops xsk_map_ops = {
261 .map_meta_equal = xsk_map_meta_equal,
262 .map_alloc = xsk_map_alloc,
263 .map_free = xsk_map_free,
264 .map_get_next_key = xsk_map_get_next_key,
265 .map_lookup_elem = xsk_map_lookup_elem,
266 .map_gen_lookup = xsk_map_gen_lookup,
267 .map_lookup_elem_sys_only = xsk_map_lookup_elem_sys_only,
268 .map_update_elem = xsk_map_update_elem,
269 .map_delete_elem = xsk_map_delete_elem,
270 .map_check_btf = map_check_no_btf,
271 .map_btf_name = "xsk_map",
272 .map_btf_id = &xsk_map_btf_id,