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