1 /* 2 * Copyright (c) 2015 Patrick McHardy <kaber@trash.net> 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 version 2 as 6 * published by the Free Software Foundation. 7 * 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/init.h> 13 #include <linux/netlink.h> 14 #include <linux/netfilter.h> 15 #include <linux/netfilter/nf_tables.h> 16 #include <net/netfilter/nf_tables.h> 17 #include <net/netfilter/nf_tables_core.h> 18 19 struct nft_dynset { 20 struct nft_set *set; 21 struct nft_set_ext_tmpl tmpl; 22 enum nft_dynset_ops op:8; 23 enum nft_registers sreg_key:8; 24 enum nft_registers sreg_data:8; 25 bool invert; 26 u64 timeout; 27 struct nft_expr *expr; 28 struct nft_set_binding binding; 29 }; 30 31 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr, 32 struct nft_regs *regs) 33 { 34 const struct nft_dynset *priv = nft_expr_priv(expr); 35 struct nft_set_ext *ext; 36 u64 timeout; 37 void *elem; 38 39 if (!atomic_add_unless(&set->nelems, 1, set->size)) 40 return NULL; 41 42 timeout = priv->timeout ? : set->timeout; 43 elem = nft_set_elem_init(set, &priv->tmpl, 44 ®s->data[priv->sreg_key], 45 ®s->data[priv->sreg_data], 46 timeout, GFP_ATOMIC); 47 if (elem == NULL) 48 goto err1; 49 50 ext = nft_set_elem_ext(set, elem); 51 if (priv->expr != NULL && 52 nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0) 53 goto err2; 54 55 return elem; 56 57 err2: 58 nft_set_elem_destroy(set, elem, false); 59 err1: 60 if (set->size) 61 atomic_dec(&set->nelems); 62 return NULL; 63 } 64 65 static void nft_dynset_eval(const struct nft_expr *expr, 66 struct nft_regs *regs, 67 const struct nft_pktinfo *pkt) 68 { 69 const struct nft_dynset *priv = nft_expr_priv(expr); 70 struct nft_set *set = priv->set; 71 const struct nft_set_ext *ext; 72 const struct nft_expr *sexpr; 73 u64 timeout; 74 75 if (set->ops->update(set, ®s->data[priv->sreg_key], nft_dynset_new, 76 expr, regs, &ext)) { 77 sexpr = NULL; 78 if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR)) 79 sexpr = nft_set_ext_expr(ext); 80 81 if (priv->op == NFT_DYNSET_OP_UPDATE && 82 nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) { 83 timeout = priv->timeout ? : set->timeout; 84 *nft_set_ext_expiration(ext) = get_jiffies_64() + timeout; 85 } 86 87 if (sexpr != NULL) 88 sexpr->ops->eval(sexpr, regs, pkt); 89 90 if (priv->invert) 91 regs->verdict.code = NFT_BREAK; 92 return; 93 } 94 95 if (!priv->invert) 96 regs->verdict.code = NFT_BREAK; 97 } 98 99 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = { 100 [NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING, 101 .len = NFT_SET_MAXNAMELEN - 1 }, 102 [NFTA_DYNSET_SET_ID] = { .type = NLA_U32 }, 103 [NFTA_DYNSET_OP] = { .type = NLA_U32 }, 104 [NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 }, 105 [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 }, 106 [NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 }, 107 [NFTA_DYNSET_EXPR] = { .type = NLA_NESTED }, 108 [NFTA_DYNSET_FLAGS] = { .type = NLA_U32 }, 109 }; 110 111 static int nft_dynset_init(const struct nft_ctx *ctx, 112 const struct nft_expr *expr, 113 const struct nlattr * const tb[]) 114 { 115 struct nft_dynset *priv = nft_expr_priv(expr); 116 u8 genmask = nft_genmask_next(ctx->net); 117 struct nft_set *set; 118 u64 timeout; 119 int err; 120 121 lockdep_assert_held(&ctx->net->nft.commit_mutex); 122 123 if (tb[NFTA_DYNSET_SET_NAME] == NULL || 124 tb[NFTA_DYNSET_OP] == NULL || 125 tb[NFTA_DYNSET_SREG_KEY] == NULL) 126 return -EINVAL; 127 128 if (tb[NFTA_DYNSET_FLAGS]) { 129 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS])); 130 131 if (flags & ~NFT_DYNSET_F_INV) 132 return -EINVAL; 133 if (flags & NFT_DYNSET_F_INV) 134 priv->invert = true; 135 } 136 137 set = nft_set_lookup_global(ctx->net, ctx->table, 138 tb[NFTA_DYNSET_SET_NAME], 139 tb[NFTA_DYNSET_SET_ID], genmask); 140 if (IS_ERR(set)) 141 return PTR_ERR(set); 142 143 if (set->ops->update == NULL) 144 return -EOPNOTSUPP; 145 146 if (set->flags & NFT_SET_CONSTANT) 147 return -EBUSY; 148 149 priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP])); 150 switch (priv->op) { 151 case NFT_DYNSET_OP_ADD: 152 break; 153 case NFT_DYNSET_OP_UPDATE: 154 if (!(set->flags & NFT_SET_TIMEOUT)) 155 return -EOPNOTSUPP; 156 break; 157 default: 158 return -EOPNOTSUPP; 159 } 160 161 timeout = 0; 162 if (tb[NFTA_DYNSET_TIMEOUT] != NULL) { 163 if (!(set->flags & NFT_SET_TIMEOUT)) 164 return -EINVAL; 165 timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64( 166 tb[NFTA_DYNSET_TIMEOUT]))); 167 } 168 169 priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]); 170 err = nft_validate_register_load(priv->sreg_key, set->klen); 171 if (err < 0) 172 return err; 173 174 if (tb[NFTA_DYNSET_SREG_DATA] != NULL) { 175 if (!(set->flags & NFT_SET_MAP)) 176 return -EINVAL; 177 if (set->dtype == NFT_DATA_VERDICT) 178 return -EOPNOTSUPP; 179 180 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]); 181 err = nft_validate_register_load(priv->sreg_data, set->dlen); 182 if (err < 0) 183 return err; 184 } else if (set->flags & NFT_SET_MAP) 185 return -EINVAL; 186 187 if (tb[NFTA_DYNSET_EXPR] != NULL) { 188 if (!(set->flags & NFT_SET_EVAL)) 189 return -EINVAL; 190 191 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]); 192 if (IS_ERR(priv->expr)) 193 return PTR_ERR(priv->expr); 194 195 err = -EOPNOTSUPP; 196 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL)) 197 goto err1; 198 199 if (priv->expr->ops->type->flags & NFT_EXPR_GC) { 200 if (set->flags & NFT_SET_TIMEOUT) 201 goto err1; 202 if (!set->ops->gc_init) 203 goto err1; 204 set->ops->gc_init(set); 205 } 206 } 207 208 nft_set_ext_prepare(&priv->tmpl); 209 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen); 210 if (set->flags & NFT_SET_MAP) 211 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen); 212 if (priv->expr != NULL) 213 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR, 214 priv->expr->ops->size); 215 if (set->flags & NFT_SET_TIMEOUT) { 216 if (timeout || set->timeout) 217 nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION); 218 } 219 220 priv->timeout = timeout; 221 222 err = nf_tables_bind_set(ctx, set, &priv->binding); 223 if (err < 0) 224 goto err1; 225 226 if (set->size == 0) 227 set->size = 0xffff; 228 229 priv->set = set; 230 return 0; 231 232 err1: 233 if (priv->expr != NULL) 234 nft_expr_destroy(ctx, priv->expr); 235 return err; 236 } 237 238 static void nft_dynset_activate(const struct nft_ctx *ctx, 239 const struct nft_expr *expr) 240 { 241 struct nft_dynset *priv = nft_expr_priv(expr); 242 243 nf_tables_rebind_set(ctx, priv->set, &priv->binding); 244 } 245 246 static void nft_dynset_deactivate(const struct nft_ctx *ctx, 247 const struct nft_expr *expr) 248 { 249 struct nft_dynset *priv = nft_expr_priv(expr); 250 251 nf_tables_unbind_set(ctx, priv->set, &priv->binding); 252 } 253 254 static void nft_dynset_destroy(const struct nft_ctx *ctx, 255 const struct nft_expr *expr) 256 { 257 struct nft_dynset *priv = nft_expr_priv(expr); 258 259 if (priv->expr != NULL) 260 nft_expr_destroy(ctx, priv->expr); 261 262 nf_tables_destroy_set(ctx, priv->set); 263 } 264 265 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr) 266 { 267 const struct nft_dynset *priv = nft_expr_priv(expr); 268 u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0; 269 270 if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key)) 271 goto nla_put_failure; 272 if (priv->set->flags & NFT_SET_MAP && 273 nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data)) 274 goto nla_put_failure; 275 if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op))) 276 goto nla_put_failure; 277 if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name)) 278 goto nla_put_failure; 279 if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT, 280 cpu_to_be64(jiffies_to_msecs(priv->timeout)), 281 NFTA_DYNSET_PAD)) 282 goto nla_put_failure; 283 if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr)) 284 goto nla_put_failure; 285 if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags))) 286 goto nla_put_failure; 287 return 0; 288 289 nla_put_failure: 290 return -1; 291 } 292 293 static const struct nft_expr_ops nft_dynset_ops = { 294 .type = &nft_dynset_type, 295 .size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)), 296 .eval = nft_dynset_eval, 297 .init = nft_dynset_init, 298 .destroy = nft_dynset_destroy, 299 .activate = nft_dynset_activate, 300 .deactivate = nft_dynset_deactivate, 301 .dump = nft_dynset_dump, 302 }; 303 304 struct nft_expr_type nft_dynset_type __read_mostly = { 305 .name = "dynset", 306 .ops = &nft_dynset_ops, 307 .policy = nft_dynset_policy, 308 .maxattr = NFTA_DYNSET_MAX, 309 .owner = THIS_MODULE, 310 }; 311