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 u64 timeout; 26 struct nft_expr *expr; 27 struct nft_set_binding binding; 28 }; 29 30 static void *nft_dynset_new(struct nft_set *set, const struct nft_expr *expr, 31 struct nft_regs *regs) 32 { 33 const struct nft_dynset *priv = nft_expr_priv(expr); 34 struct nft_set_ext *ext; 35 u64 timeout; 36 void *elem; 37 38 if (set->size && !atomic_add_unless(&set->nelems, 1, set->size)) 39 return NULL; 40 41 timeout = priv->timeout ? : set->timeout; 42 elem = nft_set_elem_init(set, &priv->tmpl, 43 ®s->data[priv->sreg_key], 44 ®s->data[priv->sreg_data], 45 timeout, GFP_ATOMIC); 46 if (elem == NULL) { 47 if (set->size) 48 atomic_dec(&set->nelems); 49 return NULL; 50 } 51 52 ext = nft_set_elem_ext(set, elem); 53 if (priv->expr != NULL && 54 nft_expr_clone(nft_set_ext_expr(ext), priv->expr) < 0) 55 return NULL; 56 57 return elem; 58 } 59 60 static void nft_dynset_eval(const struct nft_expr *expr, 61 struct nft_regs *regs, 62 const struct nft_pktinfo *pkt) 63 { 64 const struct nft_dynset *priv = nft_expr_priv(expr); 65 struct nft_set *set = priv->set; 66 const struct nft_set_ext *ext; 67 const struct nft_expr *sexpr; 68 u64 timeout; 69 70 if (set->ops->update(set, ®s->data[priv->sreg_key], nft_dynset_new, 71 expr, regs, &ext)) { 72 sexpr = NULL; 73 if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR)) 74 sexpr = nft_set_ext_expr(ext); 75 76 if (priv->op == NFT_DYNSET_OP_UPDATE && 77 nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) { 78 timeout = priv->timeout ? : set->timeout; 79 *nft_set_ext_expiration(ext) = jiffies + timeout; 80 } else if (sexpr == NULL) 81 goto out; 82 83 if (sexpr != NULL) 84 sexpr->ops->eval(sexpr, regs, pkt); 85 return; 86 } 87 out: 88 regs->verdict.code = NFT_BREAK; 89 } 90 91 static const struct nla_policy nft_dynset_policy[NFTA_DYNSET_MAX + 1] = { 92 [NFTA_DYNSET_SET_NAME] = { .type = NLA_STRING }, 93 [NFTA_DYNSET_SET_ID] = { .type = NLA_U32 }, 94 [NFTA_DYNSET_OP] = { .type = NLA_U32 }, 95 [NFTA_DYNSET_SREG_KEY] = { .type = NLA_U32 }, 96 [NFTA_DYNSET_SREG_DATA] = { .type = NLA_U32 }, 97 [NFTA_DYNSET_TIMEOUT] = { .type = NLA_U64 }, 98 [NFTA_DYNSET_EXPR] = { .type = NLA_NESTED }, 99 }; 100 101 static int nft_dynset_init(const struct nft_ctx *ctx, 102 const struct nft_expr *expr, 103 const struct nlattr * const tb[]) 104 { 105 struct nft_dynset *priv = nft_expr_priv(expr); 106 struct nft_set *set; 107 u64 timeout; 108 int err; 109 110 if (tb[NFTA_DYNSET_SET_NAME] == NULL || 111 tb[NFTA_DYNSET_OP] == NULL || 112 tb[NFTA_DYNSET_SREG_KEY] == NULL) 113 return -EINVAL; 114 115 set = nf_tables_set_lookup(ctx->table, tb[NFTA_DYNSET_SET_NAME]); 116 if (IS_ERR(set)) { 117 if (tb[NFTA_DYNSET_SET_ID]) 118 set = nf_tables_set_lookup_byid(ctx->net, 119 tb[NFTA_DYNSET_SET_ID]); 120 if (IS_ERR(set)) 121 return PTR_ERR(set); 122 } 123 124 if (set->flags & NFT_SET_CONSTANT) 125 return -EBUSY; 126 127 priv->op = ntohl(nla_get_be32(tb[NFTA_DYNSET_OP])); 128 switch (priv->op) { 129 case NFT_DYNSET_OP_ADD: 130 break; 131 case NFT_DYNSET_OP_UPDATE: 132 if (!(set->flags & NFT_SET_TIMEOUT)) 133 return -EOPNOTSUPP; 134 break; 135 default: 136 return -EOPNOTSUPP; 137 } 138 139 timeout = 0; 140 if (tb[NFTA_DYNSET_TIMEOUT] != NULL) { 141 if (!(set->flags & NFT_SET_TIMEOUT)) 142 return -EINVAL; 143 timeout = be64_to_cpu(nla_get_be64(tb[NFTA_DYNSET_TIMEOUT])); 144 } 145 146 priv->sreg_key = nft_parse_register(tb[NFTA_DYNSET_SREG_KEY]); 147 err = nft_validate_register_load(priv->sreg_key, set->klen);; 148 if (err < 0) 149 return err; 150 151 if (tb[NFTA_DYNSET_SREG_DATA] != NULL) { 152 if (!(set->flags & NFT_SET_MAP)) 153 return -EINVAL; 154 if (set->dtype == NFT_DATA_VERDICT) 155 return -EOPNOTSUPP; 156 157 priv->sreg_data = nft_parse_register(tb[NFTA_DYNSET_SREG_DATA]); 158 err = nft_validate_register_load(priv->sreg_data, set->dlen); 159 if (err < 0) 160 return err; 161 } else if (set->flags & NFT_SET_MAP) 162 return -EINVAL; 163 164 if (tb[NFTA_DYNSET_EXPR] != NULL) { 165 if (!(set->flags & NFT_SET_EVAL)) 166 return -EINVAL; 167 if (!(set->flags & NFT_SET_ANONYMOUS)) 168 return -EOPNOTSUPP; 169 170 priv->expr = nft_expr_init(ctx, tb[NFTA_DYNSET_EXPR]); 171 if (IS_ERR(priv->expr)) 172 return PTR_ERR(priv->expr); 173 174 err = -EOPNOTSUPP; 175 if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL)) 176 goto err1; 177 } else if (set->flags & NFT_SET_EVAL) 178 return -EINVAL; 179 180 nft_set_ext_prepare(&priv->tmpl); 181 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_KEY, set->klen); 182 if (set->flags & NFT_SET_MAP) 183 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_DATA, set->dlen); 184 if (priv->expr != NULL) 185 nft_set_ext_add_length(&priv->tmpl, NFT_SET_EXT_EXPR, 186 priv->expr->ops->size); 187 if (set->flags & NFT_SET_TIMEOUT) { 188 if (timeout || set->timeout) 189 nft_set_ext_add(&priv->tmpl, NFT_SET_EXT_EXPIRATION); 190 } 191 192 priv->timeout = timeout; 193 194 err = nf_tables_bind_set(ctx, set, &priv->binding); 195 if (err < 0) 196 goto err1; 197 198 priv->set = set; 199 return 0; 200 201 err1: 202 if (priv->expr != NULL) 203 nft_expr_destroy(ctx, priv->expr); 204 return err; 205 } 206 207 static void nft_dynset_destroy(const struct nft_ctx *ctx, 208 const struct nft_expr *expr) 209 { 210 struct nft_dynset *priv = nft_expr_priv(expr); 211 212 nf_tables_unbind_set(ctx, priv->set, &priv->binding); 213 if (priv->expr != NULL) 214 nft_expr_destroy(ctx, priv->expr); 215 } 216 217 static int nft_dynset_dump(struct sk_buff *skb, const struct nft_expr *expr) 218 { 219 const struct nft_dynset *priv = nft_expr_priv(expr); 220 221 if (nft_dump_register(skb, NFTA_DYNSET_SREG_KEY, priv->sreg_key)) 222 goto nla_put_failure; 223 if (priv->set->flags & NFT_SET_MAP && 224 nft_dump_register(skb, NFTA_DYNSET_SREG_DATA, priv->sreg_data)) 225 goto nla_put_failure; 226 if (nla_put_be32(skb, NFTA_DYNSET_OP, htonl(priv->op))) 227 goto nla_put_failure; 228 if (nla_put_string(skb, NFTA_DYNSET_SET_NAME, priv->set->name)) 229 goto nla_put_failure; 230 if (nla_put_be64(skb, NFTA_DYNSET_TIMEOUT, cpu_to_be64(priv->timeout), 231 NFTA_DYNSET_PAD)) 232 goto nla_put_failure; 233 if (priv->expr && nft_expr_dump(skb, NFTA_DYNSET_EXPR, priv->expr)) 234 goto nla_put_failure; 235 return 0; 236 237 nla_put_failure: 238 return -1; 239 } 240 241 static struct nft_expr_type nft_dynset_type; 242 static const struct nft_expr_ops nft_dynset_ops = { 243 .type = &nft_dynset_type, 244 .size = NFT_EXPR_SIZE(sizeof(struct nft_dynset)), 245 .eval = nft_dynset_eval, 246 .init = nft_dynset_init, 247 .destroy = nft_dynset_destroy, 248 .dump = nft_dynset_dump, 249 }; 250 251 static struct nft_expr_type nft_dynset_type __read_mostly = { 252 .name = "dynset", 253 .ops = &nft_dynset_ops, 254 .policy = nft_dynset_policy, 255 .maxattr = NFTA_DYNSET_MAX, 256 .owner = THIS_MODULE, 257 }; 258 259 int __init nft_dynset_module_init(void) 260 { 261 return nft_register_expr(&nft_dynset_type); 262 } 263 264 void nft_dynset_module_exit(void) 265 { 266 nft_unregister_expr(&nft_dynset_type); 267 } 268