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 (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 if (set->size) 49 atomic_dec(&set->nelems); 50 return NULL; 51 } 52 53 ext = nft_set_elem_ext(set, elem); 54 if (priv->expr != NULL && 55 nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0) 56 return NULL; 57 58 return elem; 59 } 60 61 static void nft_dynset_eval(const struct nft_expr *expr, 62 struct nft_regs *regs, 63 const struct nft_pktinfo *pkt) 64 { 65 const struct nft_dynset *priv = nft_expr_priv(expr); 66 struct nft_set *set = priv->set; 67 const struct nft_set_ext *ext; 68 const struct nft_expr *sexpr; 69 u64 timeout; 70 71 if (set->ops->update(set, ®s->data[priv->sreg_key], nft_dynset_new, 72 expr, regs, &ext)) { 73 sexpr = NULL; 74 if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR)) 75 sexpr = nft_set_ext_expr(ext); 76 77 if (priv->op == NFT_DYNSET_OP_UPDATE && 78 nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) { 79 timeout = priv->timeout ? : set->timeout; 80 *nft_set_ext_expiration(ext) = jiffies + timeout; 81 } else if (sexpr == NULL) 82 goto out; 83 84 if (sexpr != NULL) 85 sexpr->ops->eval(sexpr, regs, pkt); 86 87 if (priv->invert) 88 regs->verdict.code = NFT_BREAK; 89 return; 90 } 91 out: 92 if (!priv->invert) 93 regs->verdict.code = NFT_BREAK; 94 } 95 96 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = { 97 [NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING }, 98 [NFTA_DYNSET_SET_ID] = { .type = NLA_U32 }, 99 [NFTA_DYNSET_OP] = { .type = NLA_U32 }, 100 [NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 }, 101 [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 }, 102 [NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 }, 103 [NFTA_DYNSET_EXPR] = { .type = NLA_NESTED }, 104 [NFTA_DYNSET_FLAGS] = { .type = NLA_U32 }, 105 }; 106 107 static int nft_dynset_init(const struct nft_ctx *ctx, 108 const struct nft_expr *expr, 109 const struct nlattr * const tb[]) 110 { 111 struct nft_dynset *priv = nft_expr_priv(expr); 112 u8 genmask = nft_genmask_next(ctx->net); 113 struct nft_set *set; 114 u64 timeout; 115 int err; 116 117 if (tb[NFTA_DYNSET_SET_NAME] == NULL || 118 tb[NFTA_DYNSET_OP] == NULL || 119 tb[NFTA_DYNSET_SREG_KEY] == NULL) 120 return -EINVAL; 121 122 if (tb[NFTA_DYNSET_FLAGS]) { 123 u32 flags = ntohl(nla_get_be32(tb[NFTA_DYNSET_FLAGS])); 124 125 if (flags & ~NFT_DYNSET_F_INV) 126 return -EINVAL; 127 if (flags & NFT_DYNSET_F_INV) 128 priv->invert = true; 129 } 130 131 set = nf_tables_set_lookup(ctx->table, tb[NFTA_DYNSET_SET_NAME], 132 genmask); 133 if (IS_ERR(set)) { 134 if (tb[NFTA_DYNSET_SET_ID]) 135 set = nf_tables_set_lookup_byid(ctx->net, 136 tb[NFTA_DYNSET_SET_ID], 137 genmask); 138 if (IS_ERR(set)) 139 return PTR_ERR(set); 140 } 141 142 if (set->flags & NFT_SET_CONSTANT) 143 return -EBUSY; 144 145 priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP])); 146 switch (priv->op) { 147 case NFT_DYNSET_OP_ADD: 148 break; 149 case NFT_DYNSET_OP_UPDATE: 150 if (!(set->flags & NFT_SET_TIMEOUT)) 151 return -EOPNOTSUPP; 152 break; 153 default: 154 return -EOPNOTSUPP; 155 } 156 157 timeout = 0; 158 if (tb[NFTA_DYNSET_TIMEOUT] != NULL) { 159 if (!(set->flags & NFT_SET_TIMEOUT)) 160 return -EINVAL; 161 timeout = msecs_to_jiffies(be64_to_cpu(nla_get_be64( 162 tb[NFTA_DYNSET_TIMEOUT]))); 163 } 164 165 priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]); 166 err = nft_validate_register_load(priv->sreg_key, set->klen);; 167 if (err < 0) 168 return err; 169 170 if (tb[NFTA_DYNSET_SREG_DATA] != NULL) { 171 if (!(set->flags & NFT_SET_MAP)) 172 return -EINVAL; 173 if (set->dtype == NFT_DATA_VERDICT) 174 return -EOPNOTSUPP; 175 176 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]); 177 err = nft_validate_register_load(priv->sreg_data, set->dlen); 178 if (err < 0) 179 return err; 180 } else if (set->flags & NFT_SET_MAP) 181 return -EINVAL; 182 183 if (tb[NFTA_DYNSET_EXPR] != NULL) { 184 if (!(set->flags & NFT_SET_EVAL)) 185 return -EINVAL; 186 if (!(set->flags & NFT_SET_ANONYMOUS)) 187 return -EOPNOTSUPP; 188 189 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]); 190 if (IS_ERR(priv->expr)) 191 return PTR_ERR(priv->expr); 192 193 err = -EOPNOTSUPP; 194 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL)) 195 goto err1; 196 } else if (set->flags & NFT_SET_EVAL) 197 return -EINVAL; 198 199 nft_set_ext_prepare(&priv->tmpl); 200 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen); 201 if (set->flags & NFT_SET_MAP) 202 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen); 203 if (priv->expr != NULL) 204 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR, 205 priv->expr->ops->size); 206 if (set->flags & NFT_SET_TIMEOUT) { 207 if (timeout || set->timeout) 208 nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION); 209 } 210 211 priv->timeout = timeout; 212 213 err = nf_tables_bind_set(ctx, set, &priv->binding); 214 if (err < 0) 215 goto err1; 216 217 priv->set = set; 218 return 0; 219 220 err1: 221 if (priv->expr != NULL) 222 nft_expr_destroy(ctx, priv->expr); 223 return err; 224 } 225 226 static void nft_dynset_destroy(const struct nft_ctx *ctx, 227 const struct nft_expr *expr) 228 { 229 struct nft_dynset *priv = nft_expr_priv(expr); 230 231 nf_tables_unbind_set(ctx, priv->set, &priv->binding); 232 if (priv->expr != NULL) 233 nft_expr_destroy(ctx, priv->expr); 234 } 235 236 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr) 237 { 238 const struct nft_dynset *priv = nft_expr_priv(expr); 239 u32 flags = priv->invert ? NFT_DYNSET_F_INV : 0; 240 241 if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key)) 242 goto nla_put_failure; 243 if (priv->set->flags & NFT_SET_MAP && 244 nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data)) 245 goto nla_put_failure; 246 if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op))) 247 goto nla_put_failure; 248 if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name)) 249 goto nla_put_failure; 250 if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT, 251 cpu_to_be64(jiffies_to_msecs(priv->timeout)), 252 NFTA_DYNSET_PAD)) 253 goto nla_put_failure; 254 if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr)) 255 goto nla_put_failure; 256 if (nla_put_be32(skb, NFTA_DYNSET_FLAGS, htonl(flags))) 257 goto nla_put_failure; 258 return 0; 259 260 nla_put_failure: 261 return -1; 262 } 263 264 static struct nft_expr_type nft_dynset_type; 265 static const struct nft_expr_ops nft_dynset_ops = { 266 .type = &nft_dynset_type, 267 .size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)), 268 .eval = nft_dynset_eval, 269 .init = nft_dynset_init, 270 .destroy = nft_dynset_destroy, 271 .dump = nft_dynset_dump, 272 }; 273 274 static struct nft_expr_type nft_dynset_type __read_mostly = { 275 .name = "dynset", 276 .ops = &nft_dynset_ops, 277 .policy = nft_dynset_policy, 278 .maxattr = NFTA_DYNSET_MAX, 279 .owner = THIS_MODULE, 280 }; 281 282 int __init nft_dynset_module_init(void) 283 { 284 return nft_register_expr(&nft_dynset_type); 285 } 286 287 void nft_dynset_module_exit(void) 288 { 289 nft_unregister_expr(&nft_dynset_type); 290 } 291