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/list.h> 20 #include <linux/netdevice.h> 21 #include <linux/printk.h> 22 #include <linux/rtnetlink.h> 23 #include <linux/rwsem.h> 24 25 /* Protects bpf_prog_offload_devs and offload members of all progs. 26 * RTNL lock cannot be taken when holding this lock. 27 */ 28 static DECLARE_RWSEM(bpf_devs_lock); 29 static LIST_HEAD(bpf_prog_offload_devs); 30 31 int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr) 32 { 33 struct bpf_dev_offload *offload; 34 35 if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS && 36 attr->prog_type != BPF_PROG_TYPE_XDP) 37 return -EINVAL; 38 39 if (attr->prog_flags) 40 return -EINVAL; 41 42 offload = kzalloc(sizeof(*offload), GFP_USER); 43 if (!offload) 44 return -ENOMEM; 45 46 offload->prog = prog; 47 48 offload->netdev = dev_get_by_index(current->nsproxy->net_ns, 49 attr->prog_ifindex); 50 if (!offload->netdev) 51 goto err_free; 52 53 down_write(&bpf_devs_lock); 54 if (offload->netdev->reg_state != NETREG_REGISTERED) 55 goto err_unlock; 56 prog->aux->offload = offload; 57 list_add_tail(&offload->offloads, &bpf_prog_offload_devs); 58 dev_put(offload->netdev); 59 up_write(&bpf_devs_lock); 60 61 return 0; 62 err_unlock: 63 up_write(&bpf_devs_lock); 64 dev_put(offload->netdev); 65 err_free: 66 kfree(offload); 67 return -EINVAL; 68 } 69 70 static int __bpf_offload_ndo(struct bpf_prog *prog, enum bpf_netdev_command cmd, 71 struct netdev_bpf *data) 72 { 73 struct bpf_dev_offload *offload = prog->aux->offload; 74 struct net_device *netdev; 75 76 ASSERT_RTNL(); 77 78 if (!offload) 79 return -ENODEV; 80 netdev = offload->netdev; 81 if (!netdev->netdev_ops->ndo_bpf) 82 return -EOPNOTSUPP; 83 84 data->command = cmd; 85 86 return netdev->netdev_ops->ndo_bpf(netdev, data); 87 } 88 89 int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env) 90 { 91 struct netdev_bpf data = {}; 92 int err; 93 94 data.verifier.prog = env->prog; 95 96 rtnl_lock(); 97 err = __bpf_offload_ndo(env->prog, BPF_OFFLOAD_VERIFIER_PREP, &data); 98 if (err) 99 goto exit_unlock; 100 101 env->prog->aux->offload->dev_ops = data.verifier.ops; 102 env->prog->aux->offload->dev_state = true; 103 exit_unlock: 104 rtnl_unlock(); 105 return err; 106 } 107 108 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env, 109 int insn_idx, int prev_insn_idx) 110 { 111 struct bpf_dev_offload *offload; 112 int ret = -ENODEV; 113 114 down_read(&bpf_devs_lock); 115 offload = env->prog->aux->offload; 116 if (offload) 117 ret = offload->dev_ops->insn_hook(env, insn_idx, prev_insn_idx); 118 up_read(&bpf_devs_lock); 119 120 return ret; 121 } 122 123 static void __bpf_prog_offload_destroy(struct bpf_prog *prog) 124 { 125 struct bpf_dev_offload *offload = prog->aux->offload; 126 struct netdev_bpf data = {}; 127 128 data.offload.prog = prog; 129 130 if (offload->dev_state) 131 WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data)); 132 133 list_del_init(&offload->offloads); 134 kfree(offload); 135 prog->aux->offload = NULL; 136 } 137 138 void bpf_prog_offload_destroy(struct bpf_prog *prog) 139 { 140 rtnl_lock(); 141 down_write(&bpf_devs_lock); 142 if (prog->aux->offload) 143 __bpf_prog_offload_destroy(prog); 144 up_write(&bpf_devs_lock); 145 rtnl_unlock(); 146 } 147 148 static int bpf_prog_offload_translate(struct bpf_prog *prog) 149 { 150 struct netdev_bpf data = {}; 151 int ret; 152 153 data.offload.prog = prog; 154 155 rtnl_lock(); 156 ret = __bpf_offload_ndo(prog, BPF_OFFLOAD_TRANSLATE, &data); 157 rtnl_unlock(); 158 159 return ret; 160 } 161 162 static unsigned int bpf_prog_warn_on_exec(const void *ctx, 163 const struct bpf_insn *insn) 164 { 165 WARN(1, "attempt to execute device eBPF program on the host!"); 166 return 0; 167 } 168 169 int bpf_prog_offload_compile(struct bpf_prog *prog) 170 { 171 prog->bpf_func = bpf_prog_warn_on_exec; 172 173 return bpf_prog_offload_translate(prog); 174 } 175 176 const struct bpf_prog_ops bpf_offload_prog_ops = { 177 }; 178 179 static int bpf_offload_notification(struct notifier_block *notifier, 180 ulong event, void *ptr) 181 { 182 struct net_device *netdev = netdev_notifier_info_to_dev(ptr); 183 struct bpf_dev_offload *offload, *tmp; 184 185 ASSERT_RTNL(); 186 187 switch (event) { 188 case NETDEV_UNREGISTER: 189 /* ignore namespace changes */ 190 if (netdev->reg_state != NETREG_UNREGISTERING) 191 break; 192 193 down_write(&bpf_devs_lock); 194 list_for_each_entry_safe(offload, tmp, &bpf_prog_offload_devs, 195 offloads) { 196 if (offload->netdev == netdev) 197 __bpf_prog_offload_destroy(offload->prog); 198 } 199 up_write(&bpf_devs_lock); 200 break; 201 default: 202 break; 203 } 204 return NOTIFY_OK; 205 } 206 207 static struct notifier_block bpf_offload_notifier = { 208 .notifier_call = bpf_offload_notification, 209 }; 210 211 static int __init bpf_offload_init(void) 212 { 213 register_netdevice_notifier(&bpf_offload_notifier); 214 return 0; 215 } 216 217 subsys_initcall(bpf_offload_init); 218