1d20a1676SBjörn Töpel // SPDX-License-Identifier: GPL-2.0 2d20a1676SBjörn Töpel /* XSKMAP used for AF_XDP sockets 3d20a1676SBjörn Töpel * Copyright(c) 2018 Intel Corporation. 4d20a1676SBjörn Töpel */ 5d20a1676SBjörn Töpel 6d20a1676SBjörn Töpel #include <linux/bpf.h> 7b6459415SJakub Kicinski #include <linux/filter.h> 8d20a1676SBjörn Töpel #include <linux/capability.h> 9d20a1676SBjörn Töpel #include <net/xdp_sock.h> 10d20a1676SBjörn Töpel #include <linux/slab.h> 11d20a1676SBjörn Töpel #include <linux/sched.h> 12*c317ab71SMenglong Dong #include <linux/btf_ids.h> 13d20a1676SBjörn Töpel 14d20a1676SBjörn Töpel #include "xsk.h" 15d20a1676SBjörn Töpel 16d20a1676SBjörn Töpel static struct xsk_map_node *xsk_map_node_alloc(struct xsk_map *map, 17782347b6SToke Høiland-Jørgensen struct xdp_sock __rcu **map_entry) 18d20a1676SBjörn Töpel { 19d20a1676SBjörn Töpel struct xsk_map_node *node; 20d20a1676SBjörn Töpel 2128e1dcdeSRoman Gushchin node = bpf_map_kzalloc(&map->map, sizeof(*node), 2228e1dcdeSRoman Gushchin GFP_ATOMIC | __GFP_NOWARN); 23d20a1676SBjörn Töpel if (!node) 24d20a1676SBjörn Töpel return ERR_PTR(-ENOMEM); 25d20a1676SBjörn Töpel 26bb1b25caSZhu Yanjun bpf_map_inc(&map->map); 27d20a1676SBjörn Töpel 28d20a1676SBjörn Töpel node->map = map; 29d20a1676SBjörn Töpel node->map_entry = map_entry; 30d20a1676SBjörn Töpel return node; 31d20a1676SBjörn Töpel } 32d20a1676SBjörn Töpel 33d20a1676SBjörn Töpel static void xsk_map_node_free(struct xsk_map_node *node) 34d20a1676SBjörn Töpel { 35bb1b25caSZhu Yanjun bpf_map_put(&node->map->map); 36d20a1676SBjörn Töpel kfree(node); 37d20a1676SBjörn Töpel } 38d20a1676SBjörn Töpel 39d20a1676SBjörn Töpel static void xsk_map_sock_add(struct xdp_sock *xs, struct xsk_map_node *node) 40d20a1676SBjörn Töpel { 41d20a1676SBjörn Töpel spin_lock_bh(&xs->map_list_lock); 42d20a1676SBjörn Töpel list_add_tail(&node->node, &xs->map_list); 43d20a1676SBjörn Töpel spin_unlock_bh(&xs->map_list_lock); 44d20a1676SBjörn Töpel } 45d20a1676SBjörn Töpel 46d20a1676SBjörn Töpel static void xsk_map_sock_delete(struct xdp_sock *xs, 47782347b6SToke Høiland-Jørgensen struct xdp_sock __rcu **map_entry) 48d20a1676SBjörn Töpel { 49d20a1676SBjörn Töpel struct xsk_map_node *n, *tmp; 50d20a1676SBjörn Töpel 51d20a1676SBjörn Töpel spin_lock_bh(&xs->map_list_lock); 52d20a1676SBjörn Töpel list_for_each_entry_safe(n, tmp, &xs->map_list, node) { 53d20a1676SBjörn Töpel if (map_entry == n->map_entry) { 54d20a1676SBjörn Töpel list_del(&n->node); 55d20a1676SBjörn Töpel xsk_map_node_free(n); 56d20a1676SBjörn Töpel } 57d20a1676SBjörn Töpel } 58d20a1676SBjörn Töpel spin_unlock_bh(&xs->map_list_lock); 59d20a1676SBjörn Töpel } 60d20a1676SBjörn Töpel 61d20a1676SBjörn Töpel static struct bpf_map *xsk_map_alloc(union bpf_attr *attr) 62d20a1676SBjörn Töpel { 63d20a1676SBjörn Töpel struct xsk_map *m; 64819a4f32SRoman Gushchin int numa_node; 65d20a1676SBjörn Töpel u64 size; 66d20a1676SBjörn Töpel 67d20a1676SBjörn Töpel if (!capable(CAP_NET_ADMIN)) 68d20a1676SBjörn Töpel return ERR_PTR(-EPERM); 69d20a1676SBjörn Töpel 70d20a1676SBjörn Töpel if (attr->max_entries == 0 || attr->key_size != 4 || 71d20a1676SBjörn Töpel attr->value_size != 4 || 72d20a1676SBjörn Töpel attr->map_flags & ~(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)) 73d20a1676SBjörn Töpel return ERR_PTR(-EINVAL); 74d20a1676SBjörn Töpel 75d20a1676SBjörn Töpel numa_node = bpf_map_attr_numa_node(attr); 76d20a1676SBjörn Töpel size = struct_size(m, xsk_map, attr->max_entries); 77d20a1676SBjörn Töpel 78d20a1676SBjörn Töpel m = bpf_map_area_alloc(size, numa_node); 79819a4f32SRoman Gushchin if (!m) 80d20a1676SBjörn Töpel return ERR_PTR(-ENOMEM); 81d20a1676SBjörn Töpel 82d20a1676SBjörn Töpel bpf_map_init_from_attr(&m->map, attr); 83d20a1676SBjörn Töpel spin_lock_init(&m->lock); 84d20a1676SBjörn Töpel 85d20a1676SBjörn Töpel return &m->map; 86d20a1676SBjörn Töpel } 87d20a1676SBjörn Töpel 88d20a1676SBjörn Töpel static void xsk_map_free(struct bpf_map *map) 89d20a1676SBjörn Töpel { 90d20a1676SBjörn Töpel struct xsk_map *m = container_of(map, struct xsk_map, map); 91d20a1676SBjörn Töpel 92d20a1676SBjörn Töpel synchronize_net(); 93d20a1676SBjörn Töpel bpf_map_area_free(m); 94d20a1676SBjörn Töpel } 95d20a1676SBjörn Töpel 96d20a1676SBjörn Töpel static int xsk_map_get_next_key(struct bpf_map *map, void *key, void *next_key) 97d20a1676SBjörn Töpel { 98d20a1676SBjörn Töpel struct xsk_map *m = container_of(map, struct xsk_map, map); 99d20a1676SBjörn Töpel u32 index = key ? *(u32 *)key : U32_MAX; 100d20a1676SBjörn Töpel u32 *next = next_key; 101d20a1676SBjörn Töpel 102d20a1676SBjörn Töpel if (index >= m->map.max_entries) { 103d20a1676SBjörn Töpel *next = 0; 104d20a1676SBjörn Töpel return 0; 105d20a1676SBjörn Töpel } 106d20a1676SBjörn Töpel 107d20a1676SBjörn Töpel if (index == m->map.max_entries - 1) 108d20a1676SBjörn Töpel return -ENOENT; 109d20a1676SBjörn Töpel *next = index + 1; 110d20a1676SBjörn Töpel return 0; 111d20a1676SBjörn Töpel } 112d20a1676SBjörn Töpel 1134a8f87e6SDaniel Borkmann static int xsk_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf) 114d20a1676SBjörn Töpel { 115d20a1676SBjörn Töpel const int ret = BPF_REG_0, mp = BPF_REG_1, index = BPF_REG_2; 116d20a1676SBjörn Töpel struct bpf_insn *insn = insn_buf; 117d20a1676SBjörn Töpel 118d20a1676SBjörn Töpel *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0); 119d20a1676SBjörn Töpel *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5); 120d20a1676SBjörn Töpel *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(sizeof(struct xsk_sock *))); 121d20a1676SBjörn Töpel *insn++ = BPF_ALU64_IMM(BPF_ADD, mp, offsetof(struct xsk_map, xsk_map)); 122d20a1676SBjörn Töpel *insn++ = BPF_ALU64_REG(BPF_ADD, ret, mp); 123d20a1676SBjörn Töpel *insn++ = BPF_LDX_MEM(BPF_SIZEOF(struct xsk_sock *), ret, ret, 0); 124d20a1676SBjörn Töpel *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); 125d20a1676SBjörn Töpel *insn++ = BPF_MOV64_IMM(ret, 0); 126d20a1676SBjörn Töpel return insn - insn_buf; 127d20a1676SBjörn Töpel } 128d20a1676SBjörn Töpel 129782347b6SToke Høiland-Jørgensen /* Elements are kept alive by RCU; either by rcu_read_lock() (from syscall) or 130782347b6SToke Høiland-Jørgensen * by local_bh_disable() (from XDP calls inside NAPI). The 131782347b6SToke Høiland-Jørgensen * rcu_read_lock_bh_held() below makes lockdep accept both. 132782347b6SToke Høiland-Jørgensen */ 133e6a4750fSBjörn Töpel static void *__xsk_map_lookup_elem(struct bpf_map *map, u32 key) 134e6a4750fSBjörn Töpel { 135e6a4750fSBjörn Töpel struct xsk_map *m = container_of(map, struct xsk_map, map); 136e6a4750fSBjörn Töpel 137e6a4750fSBjörn Töpel if (key >= map->max_entries) 138e6a4750fSBjörn Töpel return NULL; 139e6a4750fSBjörn Töpel 140782347b6SToke Høiland-Jørgensen return rcu_dereference_check(m->xsk_map[key], rcu_read_lock_bh_held()); 141e6a4750fSBjörn Töpel } 142e6a4750fSBjörn Töpel 143d20a1676SBjörn Töpel static void *xsk_map_lookup_elem(struct bpf_map *map, void *key) 144d20a1676SBjörn Töpel { 145d20a1676SBjörn Töpel return __xsk_map_lookup_elem(map, *(u32 *)key); 146d20a1676SBjörn Töpel } 147d20a1676SBjörn Töpel 148d20a1676SBjörn Töpel static void *xsk_map_lookup_elem_sys_only(struct bpf_map *map, void *key) 149d20a1676SBjörn Töpel { 150d20a1676SBjörn Töpel return ERR_PTR(-EOPNOTSUPP); 151d20a1676SBjörn Töpel } 152d20a1676SBjörn Töpel 153d20a1676SBjörn Töpel static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value, 154d20a1676SBjörn Töpel u64 map_flags) 155d20a1676SBjörn Töpel { 156d20a1676SBjörn Töpel struct xsk_map *m = container_of(map, struct xsk_map, map); 157782347b6SToke Høiland-Jørgensen struct xdp_sock __rcu **map_entry; 158782347b6SToke Høiland-Jørgensen struct xdp_sock *xs, *old_xs; 159d20a1676SBjörn Töpel u32 i = *(u32 *)key, fd = *(u32 *)value; 160d20a1676SBjörn Töpel struct xsk_map_node *node; 161d20a1676SBjörn Töpel struct socket *sock; 162d20a1676SBjörn Töpel int err; 163d20a1676SBjörn Töpel 164d20a1676SBjörn Töpel if (unlikely(map_flags > BPF_EXIST)) 165d20a1676SBjörn Töpel return -EINVAL; 166d20a1676SBjörn Töpel if (unlikely(i >= m->map.max_entries)) 167d20a1676SBjörn Töpel return -E2BIG; 168d20a1676SBjörn Töpel 169d20a1676SBjörn Töpel sock = sockfd_lookup(fd, &err); 170d20a1676SBjörn Töpel if (!sock) 171d20a1676SBjörn Töpel return err; 172d20a1676SBjörn Töpel 173d20a1676SBjörn Töpel if (sock->sk->sk_family != PF_XDP) { 174d20a1676SBjörn Töpel sockfd_put(sock); 175d20a1676SBjörn Töpel return -EOPNOTSUPP; 176d20a1676SBjörn Töpel } 177d20a1676SBjörn Töpel 178d20a1676SBjörn Töpel xs = (struct xdp_sock *)sock->sk; 179d20a1676SBjörn Töpel 180d20a1676SBjörn Töpel map_entry = &m->xsk_map[i]; 181d20a1676SBjörn Töpel node = xsk_map_node_alloc(m, map_entry); 182d20a1676SBjörn Töpel if (IS_ERR(node)) { 183d20a1676SBjörn Töpel sockfd_put(sock); 184d20a1676SBjörn Töpel return PTR_ERR(node); 185d20a1676SBjörn Töpel } 186d20a1676SBjörn Töpel 187d20a1676SBjörn Töpel spin_lock_bh(&m->lock); 188782347b6SToke Høiland-Jørgensen old_xs = rcu_dereference_protected(*map_entry, lockdep_is_held(&m->lock)); 189d20a1676SBjörn Töpel if (old_xs == xs) { 190d20a1676SBjörn Töpel err = 0; 191d20a1676SBjörn Töpel goto out; 192d20a1676SBjörn Töpel } else if (old_xs && map_flags == BPF_NOEXIST) { 193d20a1676SBjörn Töpel err = -EEXIST; 194d20a1676SBjörn Töpel goto out; 195d20a1676SBjörn Töpel } else if (!old_xs && map_flags == BPF_EXIST) { 196d20a1676SBjörn Töpel err = -ENOENT; 197d20a1676SBjörn Töpel goto out; 198d20a1676SBjörn Töpel } 199d20a1676SBjörn Töpel xsk_map_sock_add(xs, node); 200782347b6SToke Høiland-Jørgensen rcu_assign_pointer(*map_entry, xs); 201d20a1676SBjörn Töpel if (old_xs) 202d20a1676SBjörn Töpel xsk_map_sock_delete(old_xs, map_entry); 203d20a1676SBjörn Töpel spin_unlock_bh(&m->lock); 204d20a1676SBjörn Töpel sockfd_put(sock); 205d20a1676SBjörn Töpel return 0; 206d20a1676SBjörn Töpel 207d20a1676SBjörn Töpel out: 208d20a1676SBjörn Töpel spin_unlock_bh(&m->lock); 209d20a1676SBjörn Töpel sockfd_put(sock); 210d20a1676SBjörn Töpel xsk_map_node_free(node); 211d20a1676SBjörn Töpel return err; 212d20a1676SBjörn Töpel } 213d20a1676SBjörn Töpel 214d20a1676SBjörn Töpel static int xsk_map_delete_elem(struct bpf_map *map, void *key) 215d20a1676SBjörn Töpel { 216d20a1676SBjörn Töpel struct xsk_map *m = container_of(map, struct xsk_map, map); 217782347b6SToke Høiland-Jørgensen struct xdp_sock __rcu **map_entry; 218782347b6SToke Høiland-Jørgensen struct xdp_sock *old_xs; 219d20a1676SBjörn Töpel int k = *(u32 *)key; 220d20a1676SBjörn Töpel 221d20a1676SBjörn Töpel if (k >= map->max_entries) 222d20a1676SBjörn Töpel return -EINVAL; 223d20a1676SBjörn Töpel 224d20a1676SBjörn Töpel spin_lock_bh(&m->lock); 225d20a1676SBjörn Töpel map_entry = &m->xsk_map[k]; 226782347b6SToke Høiland-Jørgensen old_xs = unrcu_pointer(xchg(map_entry, NULL)); 227d20a1676SBjörn Töpel if (old_xs) 228d20a1676SBjörn Töpel xsk_map_sock_delete(old_xs, map_entry); 229d20a1676SBjörn Töpel spin_unlock_bh(&m->lock); 230d20a1676SBjörn Töpel 231d20a1676SBjörn Töpel return 0; 232d20a1676SBjörn Töpel } 233d20a1676SBjörn Töpel 234e6a4750fSBjörn Töpel static int xsk_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags) 235e6a4750fSBjörn Töpel { 236e624d4edSHangbin Liu return __bpf_xdp_redirect_map(map, ifindex, flags, 0, 237e624d4edSHangbin Liu __xsk_map_lookup_elem); 238e6a4750fSBjörn Töpel } 239e6a4750fSBjörn Töpel 240d20a1676SBjörn Töpel void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs, 241782347b6SToke Høiland-Jørgensen struct xdp_sock __rcu **map_entry) 242d20a1676SBjörn Töpel { 243d20a1676SBjörn Töpel spin_lock_bh(&map->lock); 244782347b6SToke Høiland-Jørgensen if (rcu_access_pointer(*map_entry) == xs) { 245782347b6SToke Høiland-Jørgensen rcu_assign_pointer(*map_entry, NULL); 246d20a1676SBjörn Töpel xsk_map_sock_delete(xs, map_entry); 247d20a1676SBjörn Töpel } 248d20a1676SBjörn Töpel spin_unlock_bh(&map->lock); 249d20a1676SBjörn Töpel } 250d20a1676SBjörn Töpel 251134fede4SMartin KaFai Lau static bool xsk_map_meta_equal(const struct bpf_map *meta0, 252134fede4SMartin KaFai Lau const struct bpf_map *meta1) 253134fede4SMartin KaFai Lau { 254134fede4SMartin KaFai Lau return meta0->max_entries == meta1->max_entries && 255134fede4SMartin KaFai Lau bpf_map_meta_equal(meta0, meta1); 256134fede4SMartin KaFai Lau } 257134fede4SMartin KaFai Lau 258*c317ab71SMenglong Dong BTF_ID_LIST_SINGLE(xsk_map_btf_ids, struct, xsk_map) 259d20a1676SBjörn Töpel const struct bpf_map_ops xsk_map_ops = { 260134fede4SMartin KaFai Lau .map_meta_equal = xsk_map_meta_equal, 261d20a1676SBjörn Töpel .map_alloc = xsk_map_alloc, 262d20a1676SBjörn Töpel .map_free = xsk_map_free, 263d20a1676SBjörn Töpel .map_get_next_key = xsk_map_get_next_key, 264d20a1676SBjörn Töpel .map_lookup_elem = xsk_map_lookup_elem, 265d20a1676SBjörn Töpel .map_gen_lookup = xsk_map_gen_lookup, 266d20a1676SBjörn Töpel .map_lookup_elem_sys_only = xsk_map_lookup_elem_sys_only, 267d20a1676SBjörn Töpel .map_update_elem = xsk_map_update_elem, 268d20a1676SBjörn Töpel .map_delete_elem = xsk_map_delete_elem, 269d20a1676SBjörn Töpel .map_check_btf = map_check_no_btf, 270*c317ab71SMenglong Dong .map_btf_id = &xsk_map_btf_ids[0], 271e6a4750fSBjörn Töpel .map_redirect = xsk_map_redirect, 272d20a1676SBjörn Töpel }; 273