1 /* 2 * Copyright (C) 2017 Netronome Systems, Inc. 3 * 4 * This software is licensed under the GNU General License Version 2, 5 * June 1991 as shown in the file COPYING in the top-level directory of this 6 * source tree. 7 * 8 * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" 9 * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, 10 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 11 * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE 12 * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME 13 * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 14 */ 15 16 #include <linux/bpf.h> 17 #include <linux/bpf_verifier.h> 18 #include <linux/bug.h> 19 #include <linux/kdev_t.h> 20 #include <linux/list.h> 21 #include <linux/netdevice.h> 22 #include <linux/printk.h> 23 #include <linux/proc_ns.h> 24 #include <linux/rtnetlink.h> 25 #include <linux/rwsem.h> 26 27 /* Protects bpf_prog_offload_devs and offload members of all progs. 28 * RTNL lock cannot be taken when holding this lock. 29 */ 30 static DECLARE_RWSEM(bpf_devs_lock); 31 static LIST_HEAD(bpf_prog_offload_devs); 32 33 int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr) 34 { 35 struct bpf_dev_offload *offload; 36 37 if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS && 38 attr->prog_type != BPF_PROG_TYPE_XDP) 39 return -EINVAL; 40 41 if (attr->prog_flags) 42 return -EINVAL; 43 44 offload = kzalloc(sizeof(*offload), GFP_USER); 45 if (!offload) 46 return -ENOMEM; 47 48 offload->prog = prog; 49 50 offload->netdev = dev_get_by_index(current->nsproxy->net_ns, 51 attr->prog_ifindex); 52 if (!offload->netdev) 53 goto err_free; 54 55 down_write(&bpf_devs_lock); 56 if (offload->netdev->reg_state != NETREG_REGISTERED) 57 goto err_unlock; 58 prog->aux->offload = offload; 59 list_add_tail(&offload->offloads, &bpf_prog_offload_devs); 60 dev_put(offload->netdev); 61 up_write(&bpf_devs_lock); 62 63 return 0; 64 err_unlock: 65 up_write(&bpf_devs_lock); 66 dev_put(offload->netdev); 67 err_free: 68 kfree(offload); 69 return -EINVAL; 70 } 71 72 static int __bpf_offload_ndo(struct bpf_prog *prog, enum bpf_netdev_command cmd, 73 struct netdev_bpf *data) 74 { 75 struct bpf_dev_offload *offload = prog->aux->offload; 76 struct net_device *netdev; 77 78 ASSERT_RTNL(); 79 80 if (!offload) 81 return -ENODEV; 82 netdev = offload->netdev; 83 if (!netdev->netdev_ops->ndo_bpf) 84 return -EOPNOTSUPP; 85 86 data->command = cmd; 87 88 return netdev->netdev_ops->ndo_bpf(netdev, data); 89 } 90 91 int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env) 92 { 93 struct netdev_bpf data = {}; 94 int err; 95 96 data.verifier.prog = env->prog; 97 98 rtnl_lock(); 99 err = __bpf_offload_ndo(env->prog, BPF_OFFLOAD_VERIFIER_PREP, &data); 100 if (err) 101 goto exit_unlock; 102 103 env->prog->aux->offload->dev_ops = data.verifier.ops; 104 env->prog->aux->offload->dev_state = true; 105 exit_unlock: 106 rtnl_unlock(); 107 return err; 108 } 109 110 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env, 111 int insn_idx, int prev_insn_idx) 112 { 113 struct bpf_dev_offload *offload; 114 int ret = -ENODEV; 115 116 down_read(&bpf_devs_lock); 117 offload = env->prog->aux->offload; 118 if (offload) 119 ret = offload->dev_ops->insn_hook(env, insn_idx, prev_insn_idx); 120 up_read(&bpf_devs_lock); 121 122 return ret; 123 } 124 125 static void __bpf_prog_offload_destroy(struct bpf_prog *prog) 126 { 127 struct bpf_dev_offload *offload = prog->aux->offload; 128 struct netdev_bpf data = {}; 129 130 data.offload.prog = prog; 131 132 if (offload->dev_state) 133 WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data)); 134 135 /* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */ 136 bpf_prog_free_id(prog, true); 137 138 list_del_init(&offload->offloads); 139 kfree(offload); 140 prog->aux->offload = NULL; 141 } 142 143 void bpf_prog_offload_destroy(struct bpf_prog *prog) 144 { 145 rtnl_lock(); 146 down_write(&bpf_devs_lock); 147 if (prog->aux->offload) 148 __bpf_prog_offload_destroy(prog); 149 up_write(&bpf_devs_lock); 150 rtnl_unlock(); 151 } 152 153 static int bpf_prog_offload_translate(struct bpf_prog *prog) 154 { 155 struct netdev_bpf data = {}; 156 int ret; 157 158 data.offload.prog = prog; 159 160 rtnl_lock(); 161 ret = __bpf_offload_ndo(prog, BPF_OFFLOAD_TRANSLATE, &data); 162 rtnl_unlock(); 163 164 return ret; 165 } 166 167 static unsigned int bpf_prog_warn_on_exec(const void *ctx, 168 const struct bpf_insn *insn) 169 { 170 WARN(1, "attempt to execute device eBPF program on the host!"); 171 return 0; 172 } 173 174 int bpf_prog_offload_compile(struct bpf_prog *prog) 175 { 176 prog->bpf_func = bpf_prog_warn_on_exec; 177 178 return bpf_prog_offload_translate(prog); 179 } 180 181 struct ns_get_path_bpf_prog_args { 182 struct bpf_prog *prog; 183 struct bpf_prog_info *info; 184 }; 185 186 static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data) 187 { 188 struct ns_get_path_bpf_prog_args *args = private_data; 189 struct bpf_prog_aux *aux = args->prog->aux; 190 struct ns_common *ns; 191 struct net *net; 192 193 rtnl_lock(); 194 down_read(&bpf_devs_lock); 195 196 if (aux->offload) { 197 args->info->ifindex = aux->offload->netdev->ifindex; 198 net = dev_net(aux->offload->netdev); 199 get_net(net); 200 ns = &net->ns; 201 } else { 202 args->info->ifindex = 0; 203 ns = NULL; 204 } 205 206 up_read(&bpf_devs_lock); 207 rtnl_unlock(); 208 209 return ns; 210 } 211 212 int bpf_prog_offload_info_fill(struct bpf_prog_info *info, 213 struct bpf_prog *prog) 214 { 215 struct ns_get_path_bpf_prog_args args = { 216 .prog = prog, 217 .info = info, 218 }; 219 struct inode *ns_inode; 220 struct path ns_path; 221 void *res; 222 223 res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args); 224 if (IS_ERR(res)) { 225 if (!info->ifindex) 226 return -ENODEV; 227 return PTR_ERR(res); 228 } 229 230 ns_inode = ns_path.dentry->d_inode; 231 info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev); 232 info->netns_ino = ns_inode->i_ino; 233 path_put(&ns_path); 234 235 return 0; 236 } 237 238 const struct bpf_prog_ops bpf_offload_prog_ops = { 239 }; 240 241 static int bpf_offload_notification(struct notifier_block *notifier, 242 ulong event, void *ptr) 243 { 244 struct net_device *netdev = netdev_notifier_info_to_dev(ptr); 245 struct bpf_dev_offload *offload, *tmp; 246 247 ASSERT_RTNL(); 248 249 switch (event) { 250 case NETDEV_UNREGISTER: 251 /* ignore namespace changes */ 252 if (netdev->reg_state != NETREG_UNREGISTERING) 253 break; 254 255 down_write(&bpf_devs_lock); 256 list_for_each_entry_safe(offload, tmp, &bpf_prog_offload_devs, 257 offloads) { 258 if (offload->netdev == netdev) 259 __bpf_prog_offload_destroy(offload->prog); 260 } 261 up_write(&bpf_devs_lock); 262 break; 263 default: 264 break; 265 } 266 return NOTIFY_OK; 267 } 268 269 static struct notifier_block bpf_offload_notifier = { 270 .notifier_call = bpf_offload_notification, 271 }; 272 273 static int __init bpf_offload_init(void) 274 { 275 register_netdevice_notifier(&bpf_offload_notifier); 276 return 0; 277 } 278 279 subsys_initcall(bpf_offload_init); 280