1 /* 2 * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 */ 9 10 #include <linux/module.h> 11 #include <linux/init.h> 12 #include <linux/kernel.h> 13 #include <linux/skbuff.h> 14 #include <linux/rtnetlink.h> 15 #include <linux/filter.h> 16 #include <linux/bpf.h> 17 18 #include <net/netlink.h> 19 #include <net/pkt_sched.h> 20 21 #include <linux/tc_act/tc_bpf.h> 22 #include <net/tc_act/tc_bpf.h> 23 24 #define BPF_TAB_MASK 15 25 #define ACT_BPF_NAME_LEN 256 26 27 struct tcf_bpf_cfg { 28 struct bpf_prog *filter; 29 struct sock_filter *bpf_ops; 30 const char *bpf_name; 31 u32 bpf_fd; 32 u16 bpf_num_ops; 33 bool is_ebpf; 34 }; 35 36 static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act, 37 struct tcf_result *res) 38 { 39 struct tcf_bpf *prog = act->priv; 40 int action, filter_res; 41 bool at_ingress = G_TC_AT(skb->tc_verd) & AT_INGRESS; 42 43 if (unlikely(!skb_mac_header_was_set(skb))) 44 return TC_ACT_UNSPEC; 45 46 spin_lock(&prog->tcf_lock); 47 48 prog->tcf_tm.lastuse = jiffies; 49 bstats_update(&prog->tcf_bstats, skb); 50 51 /* Needed here for accessing maps. */ 52 rcu_read_lock(); 53 if (at_ingress) { 54 __skb_push(skb, skb->mac_len); 55 filter_res = BPF_PROG_RUN(prog->filter, skb); 56 __skb_pull(skb, skb->mac_len); 57 } else { 58 filter_res = BPF_PROG_RUN(prog->filter, skb); 59 } 60 rcu_read_unlock(); 61 62 /* A BPF program may overwrite the default action opcode. 63 * Similarly as in cls_bpf, if filter_res == -1 we use the 64 * default action specified from tc. 65 * 66 * In case a different well-known TC_ACT opcode has been 67 * returned, it will overwrite the default one. 68 * 69 * For everything else that is unkown, TC_ACT_UNSPEC is 70 * returned. 71 */ 72 switch (filter_res) { 73 case TC_ACT_PIPE: 74 case TC_ACT_RECLASSIFY: 75 case TC_ACT_OK: 76 action = filter_res; 77 break; 78 case TC_ACT_SHOT: 79 action = filter_res; 80 prog->tcf_qstats.drops++; 81 break; 82 case TC_ACT_UNSPEC: 83 action = prog->tcf_action; 84 break; 85 default: 86 action = TC_ACT_UNSPEC; 87 break; 88 } 89 90 spin_unlock(&prog->tcf_lock); 91 return action; 92 } 93 94 static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog) 95 { 96 return !prog->bpf_ops; 97 } 98 99 static int tcf_bpf_dump_bpf_info(const struct tcf_bpf *prog, 100 struct sk_buff *skb) 101 { 102 struct nlattr *nla; 103 104 if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, prog->bpf_num_ops)) 105 return -EMSGSIZE; 106 107 nla = nla_reserve(skb, TCA_ACT_BPF_OPS, prog->bpf_num_ops * 108 sizeof(struct sock_filter)); 109 if (nla == NULL) 110 return -EMSGSIZE; 111 112 memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); 113 114 return 0; 115 } 116 117 static int tcf_bpf_dump_ebpf_info(const struct tcf_bpf *prog, 118 struct sk_buff *skb) 119 { 120 if (nla_put_u32(skb, TCA_ACT_BPF_FD, prog->bpf_fd)) 121 return -EMSGSIZE; 122 123 if (prog->bpf_name && 124 nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name)) 125 return -EMSGSIZE; 126 127 return 0; 128 } 129 130 static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act, 131 int bind, int ref) 132 { 133 unsigned char *tp = skb_tail_pointer(skb); 134 struct tcf_bpf *prog = act->priv; 135 struct tc_act_bpf opt = { 136 .index = prog->tcf_index, 137 .refcnt = prog->tcf_refcnt - ref, 138 .bindcnt = prog->tcf_bindcnt - bind, 139 .action = prog->tcf_action, 140 }; 141 struct tcf_t tm; 142 int ret; 143 144 if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) 145 goto nla_put_failure; 146 147 if (tcf_bpf_is_ebpf(prog)) 148 ret = tcf_bpf_dump_ebpf_info(prog, skb); 149 else 150 ret = tcf_bpf_dump_bpf_info(prog, skb); 151 if (ret) 152 goto nla_put_failure; 153 154 tm.install = jiffies_to_clock_t(jiffies - prog->tcf_tm.install); 155 tm.lastuse = jiffies_to_clock_t(jiffies - prog->tcf_tm.lastuse); 156 tm.expires = jiffies_to_clock_t(prog->tcf_tm.expires); 157 158 if (nla_put(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm)) 159 goto nla_put_failure; 160 161 return skb->len; 162 163 nla_put_failure: 164 nlmsg_trim(skb, tp); 165 return -1; 166 } 167 168 static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { 169 [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, 170 [TCA_ACT_BPF_FD] = { .type = NLA_U32 }, 171 [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING, .len = ACT_BPF_NAME_LEN }, 172 [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, 173 [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, 174 .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, 175 }; 176 177 static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg) 178 { 179 struct sock_filter *bpf_ops; 180 struct sock_fprog_kern fprog_tmp; 181 struct bpf_prog *fp; 182 u16 bpf_size, bpf_num_ops; 183 int ret; 184 185 bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); 186 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) 187 return -EINVAL; 188 189 bpf_size = bpf_num_ops * sizeof(*bpf_ops); 190 if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS])) 191 return -EINVAL; 192 193 bpf_ops = kzalloc(bpf_size, GFP_KERNEL); 194 if (bpf_ops == NULL) 195 return -ENOMEM; 196 197 memcpy(bpf_ops, nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size); 198 199 fprog_tmp.len = bpf_num_ops; 200 fprog_tmp.filter = bpf_ops; 201 202 ret = bpf_prog_create(&fp, &fprog_tmp); 203 if (ret < 0) { 204 kfree(bpf_ops); 205 return ret; 206 } 207 208 cfg->bpf_ops = bpf_ops; 209 cfg->bpf_num_ops = bpf_num_ops; 210 cfg->filter = fp; 211 cfg->is_ebpf = false; 212 213 return 0; 214 } 215 216 static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg) 217 { 218 struct bpf_prog *fp; 219 char *name = NULL; 220 u32 bpf_fd; 221 222 bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]); 223 224 fp = bpf_prog_get(bpf_fd); 225 if (IS_ERR(fp)) 226 return PTR_ERR(fp); 227 228 if (fp->type != BPF_PROG_TYPE_SCHED_ACT) { 229 bpf_prog_put(fp); 230 return -EINVAL; 231 } 232 233 if (tb[TCA_ACT_BPF_NAME]) { 234 name = kmemdup(nla_data(tb[TCA_ACT_BPF_NAME]), 235 nla_len(tb[TCA_ACT_BPF_NAME]), 236 GFP_KERNEL); 237 if (!name) { 238 bpf_prog_put(fp); 239 return -ENOMEM; 240 } 241 } 242 243 cfg->bpf_fd = bpf_fd; 244 cfg->bpf_name = name; 245 cfg->filter = fp; 246 cfg->is_ebpf = true; 247 248 return 0; 249 } 250 251 static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg) 252 { 253 if (cfg->is_ebpf) 254 bpf_prog_put(cfg->filter); 255 else 256 bpf_prog_destroy(cfg->filter); 257 258 kfree(cfg->bpf_ops); 259 kfree(cfg->bpf_name); 260 } 261 262 static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog, 263 struct tcf_bpf_cfg *cfg) 264 { 265 cfg->is_ebpf = tcf_bpf_is_ebpf(prog); 266 cfg->filter = prog->filter; 267 268 cfg->bpf_ops = prog->bpf_ops; 269 cfg->bpf_name = prog->bpf_name; 270 } 271 272 static int tcf_bpf_init(struct net *net, struct nlattr *nla, 273 struct nlattr *est, struct tc_action *act, 274 int replace, int bind) 275 { 276 struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; 277 struct tcf_bpf_cfg cfg, old; 278 struct tc_act_bpf *parm; 279 struct tcf_bpf *prog; 280 bool is_bpf, is_ebpf; 281 int ret; 282 283 if (!nla) 284 return -EINVAL; 285 286 ret = nla_parse_nested(tb, TCA_ACT_BPF_MAX, nla, act_bpf_policy); 287 if (ret < 0) 288 return ret; 289 290 is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS]; 291 is_ebpf = tb[TCA_ACT_BPF_FD]; 292 293 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf) || 294 !tb[TCA_ACT_BPF_PARMS]) 295 return -EINVAL; 296 297 parm = nla_data(tb[TCA_ACT_BPF_PARMS]); 298 299 memset(&cfg, 0, sizeof(cfg)); 300 301 ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) : 302 tcf_bpf_init_from_efd(tb, &cfg); 303 if (ret < 0) 304 return ret; 305 306 if (!tcf_hash_check(parm->index, act, bind)) { 307 ret = tcf_hash_create(parm->index, est, act, 308 sizeof(*prog), bind); 309 if (ret < 0) 310 goto destroy_fp; 311 312 ret = ACT_P_CREATED; 313 } else { 314 /* Don't override defaults. */ 315 if (bind) 316 goto destroy_fp; 317 318 tcf_hash_release(act, bind); 319 if (!replace) { 320 ret = -EEXIST; 321 goto destroy_fp; 322 } 323 } 324 325 prog = to_bpf(act); 326 spin_lock_bh(&prog->tcf_lock); 327 328 if (ret != ACT_P_CREATED) 329 tcf_bpf_prog_fill_cfg(prog, &old); 330 331 prog->bpf_ops = cfg.bpf_ops; 332 prog->bpf_name = cfg.bpf_name; 333 334 if (cfg.bpf_num_ops) 335 prog->bpf_num_ops = cfg.bpf_num_ops; 336 if (cfg.bpf_fd) 337 prog->bpf_fd = cfg.bpf_fd; 338 339 prog->tcf_action = parm->action; 340 prog->filter = cfg.filter; 341 342 spin_unlock_bh(&prog->tcf_lock); 343 344 if (ret == ACT_P_CREATED) 345 tcf_hash_insert(act); 346 else 347 tcf_bpf_cfg_cleanup(&old); 348 349 return ret; 350 351 destroy_fp: 352 tcf_bpf_cfg_cleanup(&cfg); 353 return ret; 354 } 355 356 static void tcf_bpf_cleanup(struct tc_action *act, int bind) 357 { 358 struct tcf_bpf_cfg tmp; 359 360 tcf_bpf_prog_fill_cfg(act->priv, &tmp); 361 tcf_bpf_cfg_cleanup(&tmp); 362 } 363 364 static struct tc_action_ops act_bpf_ops __read_mostly = { 365 .kind = "bpf", 366 .type = TCA_ACT_BPF, 367 .owner = THIS_MODULE, 368 .act = tcf_bpf, 369 .dump = tcf_bpf_dump, 370 .cleanup = tcf_bpf_cleanup, 371 .init = tcf_bpf_init, 372 }; 373 374 static int __init bpf_init_module(void) 375 { 376 return tcf_register_action(&act_bpf_ops, BPF_TAB_MASK); 377 } 378 379 static void __exit bpf_cleanup_module(void) 380 { 381 tcf_unregister_action(&act_bpf_ops); 382 } 383 384 module_init(bpf_init_module); 385 module_exit(bpf_cleanup_module); 386 387 MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); 388 MODULE_DESCRIPTION("TC BPF based action"); 389 MODULE_LICENSE("GPL v2"); 390