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