1 /* 2 * Copyright (c) 2015 Patrick McHardy <[email protected]> 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 (set->size && !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) = jiffies + timeout; 85 } else if (sexpr == NULL) 86 goto out; 87 88 if (sexpr != NULL) 89 sexpr->ops->eval(sexpr, regs, pkt); 90 91 if (priv->invert) 92 regs->verdict.code = NFT_BREAK; 93 return; 94 } 95 out: 96 if (!priv->invert) 97 regs->verdict.code = NFT_BREAK; 98 } 99 100 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = { 101 [NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING, 102 .len = NFT_SET_MAXNAMELEN - 1 }, 103 [NFTA_DYNSET_SET_ID] = { .type = NLA_U32 }, 104 [NFTA_DYNSET_OP] = { .type = NLA_U32 }, 105 [NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 }, 106 [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 }, 107 [NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 }, 108 [NFTA_DYNSET_EXPR] = { .type = NLA_NESTED }, 109 [NFTA_DYNSET_FLAGS] = { .type = NLA_U32 }, 110 }; 111 112 static int nft_dynset_init(const struct nft_ctx *ctx, 113 const struct nft_expr *expr, 114 const struct nlattr * const tb[]) 115 { 116 struct nft_dynset *priv = nft_expr_priv(expr); 117 u8 genmask = nft_genmask_next(ctx->net); 118 struct nft_set *set; 119 u64 timeout; 120 int err; 121 122 if (tb[NFTA_DYNSET_SET_NAME] == NULL || 123 tb[NFTA_DYNSET_OP] == NULL || 124 tb[NFTA_DYNSET_SREG_KEY] == NULL) 125 return -EINVAL; 126 127 if (tb[NFTA_DYNSET_FLAGS]) { 128 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS])); 129 130 if (flags & ~NFT_DYNSET_F_INV) 131 return -EINVAL; 132 if (flags & NFT_DYNSET_F_INV) 133 priv->invert = true; 134 } 135 136 set = nf_tables_set_lookup(ctx->table, tb[NFTA_DYNSET_SET_NAME], 137 genmask); 138 if (IS_ERR(set)) { 139 if (tb[NFTA_DYNSET_SET_ID]) 140 set = nf_tables_set_lookup_byid(ctx->net, 141 tb[NFTA_DYNSET_SET_ID], 142 genmask); 143 if (IS_ERR(set)) 144 return PTR_ERR(set); 145 } 146 147 if (set->ops->update == NULL) 148 return -EOPNOTSUPP; 149 150 if (set->flags & NFT_SET_CONSTANT) 151 return -EBUSY; 152 153 priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP])); 154 switch (priv->op) { 155 case NFT_DYNSET_OP_ADD: 156 break; 157 case NFT_DYNSET_OP_UPDATE: 158 if (!(set->flags & NFT_SET_TIMEOUT)) 159 return -EOPNOTSUPP; 160 break; 161 default: 162 return -EOPNOTSUPP; 163 } 164 165 timeout = 0; 166 if (tb[NFTA_DYNSET_TIMEOUT] != NULL) { 167 if (!(set->flags & NFT_SET_TIMEOUT)) 168 return -EINVAL; 169 timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64( 170 tb[NFTA_DYNSET_TIMEOUT]))); 171 } 172 173 priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]); 174 err = nft_validate_register_load(priv->sreg_key, set->klen);; 175 if (err < 0) 176 return err; 177 178 if (tb[NFTA_DYNSET_SREG_DATA] != NULL) { 179 if (!(set->flags & NFT_SET_MAP)) 180 return -EINVAL; 181 if (set->dtype == NFT_DATA_VERDICT) 182 return -EOPNOTSUPP; 183 184 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]); 185 err = nft_validate_register_load(priv->sreg_data, set->dlen); 186 if (err < 0) 187 return err; 188 } else if (set->flags & NFT_SET_MAP) 189 return -EINVAL; 190 191 if (tb[NFTA_DYNSET_EXPR] != NULL) { 192 if (!(set->flags & NFT_SET_EVAL)) 193 return -EINVAL; 194 if (!(set->flags & NFT_SET_ANONYMOUS)) 195 return -EOPNOTSUPP; 196 197 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]); 198 if (IS_ERR(priv->expr)) 199 return PTR_ERR(priv->expr); 200 201 err = -EOPNOTSUPP; 202 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL)) 203 goto err1; 204 } else if (set->flags & NFT_SET_EVAL) 205 return -EINVAL; 206 207 nft_set_ext_prepare(&priv->tmpl); 208 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen); 209 if (set->flags & NFT_SET_MAP) 210 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen); 211 if (priv->expr != NULL) 212 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR, 213 priv->expr->ops->size); 214 if (set->flags & NFT_SET_TIMEOUT) { 215 if (timeout || set->timeout) 216 nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION); 217 } 218 219 priv->timeout = timeout; 220 221 err = nf_tables_bind_set(ctx, set, &priv->binding); 222 if (err < 0) 223 goto err1; 224 225 priv->set = set; 226 return 0; 227 228 err1: 229 if (priv->expr != NULL) 230 nft_expr_destroy(ctx, priv->expr); 231 return err; 232 } 233 234 static void nft_dynset_destroy(const struct nft_ctx *ctx, 235 const struct nft_expr *expr) 236 { 237 struct nft_dynset *priv = nft_expr_priv(expr); 238 239 nf_tables_unbind_set(ctx, priv->set, &priv->binding); 240 if (priv->expr != NULL) 241 nft_expr_destroy(ctx, priv->expr); 242 } 243 244 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr) 245 { 246 const struct nft_dynset *priv = nft_expr_priv(expr); 247 u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0; 248 249 if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key)) 250 goto nla_put_failure; 251 if (priv->set->flags & NFT_SET_MAP && 252 nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data)) 253 goto nla_put_failure; 254 if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op))) 255 goto nla_put_failure; 256 if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name)) 257 goto nla_put_failure; 258 if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT, 259 cpu_to_be64(jiffies_to_msecs(priv->timeout)), 260 NFTA_DYNSET_PAD)) 261 goto nla_put_failure; 262 if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr)) 263 goto nla_put_failure; 264 if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags))) 265 goto nla_put_failure; 266 return 0; 267 268 nla_put_failure: 269 return -1; 270 } 271 272 static const struct nft_expr_ops nft_dynset_ops = { 273 .type = &nft_dynset_type, 274 .size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)), 275 .eval = nft_dynset_eval, 276 .init = nft_dynset_init, 277 .destroy = nft_dynset_destroy, 278 .dump = nft_dynset_dump, 279 }; 280 281 struct nft_expr_type nft_dynset_type __read_mostly = { 282 .name = "dynset", 283 .ops = &nft_dynset_ops, 284 .policy = nft_dynset_policy, 285 .maxattr = NFTA_DYNSET_MAX, 286 .owner = THIS_MODULE, 287 }; 288