| 1 | /* |
| 2 | * Copyright (c) 2008-2009 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 | * Development of this code funded by Astaro AG (http://www.astaro.com/) |
| 9 | */ |
| 10 | |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/netlink.h> |
| 15 | #include <linux/netfilter.h> |
| 16 | #include <linux/netfilter/nf_tables.h> |
| 17 | #include <net/netfilter/nf_tables.h> |
| 18 | #include <net/netfilter/nf_conntrack.h> |
| 19 | #include <net/netfilter/nf_conntrack_tuple.h> |
| 20 | #include <net/netfilter/nf_conntrack_helper.h> |
| 21 | |
| 22 | struct nft_ct { |
| 23 | enum nft_ct_keys key:8; |
| 24 | enum ip_conntrack_dir dir:8; |
| 25 | enum nft_registers dreg:8; |
| 26 | uint8_t family; |
| 27 | }; |
| 28 | |
| 29 | static void nft_ct_eval(const struct nft_expr *expr, |
| 30 | struct nft_data data[NFT_REG_MAX + 1], |
| 31 | const struct nft_pktinfo *pkt) |
| 32 | { |
| 33 | const struct nft_ct *priv = nft_expr_priv(expr); |
| 34 | struct nft_data *dest = &data[priv->dreg]; |
| 35 | enum ip_conntrack_info ctinfo; |
| 36 | const struct nf_conn *ct; |
| 37 | const struct nf_conn_help *help; |
| 38 | const struct nf_conntrack_tuple *tuple; |
| 39 | const struct nf_conntrack_helper *helper; |
| 40 | long diff; |
| 41 | unsigned int state; |
| 42 | |
| 43 | ct = nf_ct_get(pkt->skb, &ctinfo); |
| 44 | |
| 45 | switch (priv->key) { |
| 46 | case NFT_CT_STATE: |
| 47 | if (ct == NULL) |
| 48 | state = NF_CT_STATE_INVALID_BIT; |
| 49 | else if (nf_ct_is_untracked(ct)) |
| 50 | state = NF_CT_STATE_UNTRACKED_BIT; |
| 51 | else |
| 52 | state = NF_CT_STATE_BIT(ctinfo); |
| 53 | dest->data[0] = state; |
| 54 | return; |
| 55 | } |
| 56 | |
| 57 | if (ct == NULL) |
| 58 | goto err; |
| 59 | |
| 60 | switch (priv->key) { |
| 61 | case NFT_CT_DIRECTION: |
| 62 | dest->data[0] = CTINFO2DIR(ctinfo); |
| 63 | return; |
| 64 | case NFT_CT_STATUS: |
| 65 | dest->data[0] = ct->status; |
| 66 | return; |
| 67 | #ifdef CONFIG_NF_CONNTRACK_MARK |
| 68 | case NFT_CT_MARK: |
| 69 | dest->data[0] = ct->mark; |
| 70 | return; |
| 71 | #endif |
| 72 | #ifdef CONFIG_NF_CONNTRACK_SECMARK |
| 73 | case NFT_CT_SECMARK: |
| 74 | dest->data[0] = ct->secmark; |
| 75 | return; |
| 76 | #endif |
| 77 | case NFT_CT_EXPIRATION: |
| 78 | diff = (long)jiffies - (long)ct->timeout.expires; |
| 79 | if (diff < 0) |
| 80 | diff = 0; |
| 81 | dest->data[0] = jiffies_to_msecs(diff); |
| 82 | return; |
| 83 | case NFT_CT_HELPER: |
| 84 | if (ct->master == NULL) |
| 85 | goto err; |
| 86 | help = nfct_help(ct->master); |
| 87 | if (help == NULL) |
| 88 | goto err; |
| 89 | helper = rcu_dereference(help->helper); |
| 90 | if (helper == NULL) |
| 91 | goto err; |
| 92 | if (strlen(helper->name) >= sizeof(dest->data)) |
| 93 | goto err; |
| 94 | strncpy((char *)dest->data, helper->name, sizeof(dest->data)); |
| 95 | return; |
| 96 | } |
| 97 | |
| 98 | tuple = &ct->tuplehash[priv->dir].tuple; |
| 99 | switch (priv->key) { |
| 100 | case NFT_CT_L3PROTOCOL: |
| 101 | dest->data[0] = nf_ct_l3num(ct); |
| 102 | return; |
| 103 | case NFT_CT_SRC: |
| 104 | memcpy(dest->data, tuple->src.u3.all, |
| 105 | nf_ct_l3num(ct) == NFPROTO_IPV4 ? 4 : 16); |
| 106 | return; |
| 107 | case NFT_CT_DST: |
| 108 | memcpy(dest->data, tuple->dst.u3.all, |
| 109 | nf_ct_l3num(ct) == NFPROTO_IPV4 ? 4 : 16); |
| 110 | return; |
| 111 | case NFT_CT_PROTOCOL: |
| 112 | dest->data[0] = nf_ct_protonum(ct); |
| 113 | return; |
| 114 | case NFT_CT_PROTO_SRC: |
| 115 | dest->data[0] = (__force __u16)tuple->src.u.all; |
| 116 | return; |
| 117 | case NFT_CT_PROTO_DST: |
| 118 | dest->data[0] = (__force __u16)tuple->dst.u.all; |
| 119 | return; |
| 120 | } |
| 121 | return; |
| 122 | err: |
| 123 | data[NFT_REG_VERDICT].verdict = NFT_BREAK; |
| 124 | } |
| 125 | |
| 126 | static const struct nla_policy nft_ct_policy[NFTA_CT_MAX + 1] = { |
| 127 | [NFTA_CT_DREG] = { .type = NLA_U32 }, |
| 128 | [NFTA_CT_KEY] = { .type = NLA_U32 }, |
| 129 | [NFTA_CT_DIRECTION] = { .type = NLA_U8 }, |
| 130 | }; |
| 131 | |
| 132 | static int nft_ct_init(const struct nft_ctx *ctx, |
| 133 | const struct nft_expr *expr, |
| 134 | const struct nlattr * const tb[]) |
| 135 | { |
| 136 | struct nft_ct *priv = nft_expr_priv(expr); |
| 137 | int err; |
| 138 | |
| 139 | if (tb[NFTA_CT_DREG] == NULL || |
| 140 | tb[NFTA_CT_KEY] == NULL) |
| 141 | return -EINVAL; |
| 142 | |
| 143 | priv->key = ntohl(nla_get_be32(tb[NFTA_CT_KEY])); |
| 144 | if (tb[NFTA_CT_DIRECTION] != NULL) { |
| 145 | priv->dir = nla_get_u8(tb[NFTA_CT_DIRECTION]); |
| 146 | switch (priv->dir) { |
| 147 | case IP_CT_DIR_ORIGINAL: |
| 148 | case IP_CT_DIR_REPLY: |
| 149 | break; |
| 150 | default: |
| 151 | return -EINVAL; |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | switch (priv->key) { |
| 156 | case NFT_CT_STATE: |
| 157 | case NFT_CT_DIRECTION: |
| 158 | case NFT_CT_STATUS: |
| 159 | #ifdef CONFIG_NF_CONNTRACK_MARK |
| 160 | case NFT_CT_MARK: |
| 161 | #endif |
| 162 | #ifdef CONFIG_NF_CONNTRACK_SECMARK |
| 163 | case NFT_CT_SECMARK: |
| 164 | #endif |
| 165 | case NFT_CT_EXPIRATION: |
| 166 | case NFT_CT_HELPER: |
| 167 | if (tb[NFTA_CT_DIRECTION] != NULL) |
| 168 | return -EINVAL; |
| 169 | break; |
| 170 | case NFT_CT_PROTOCOL: |
| 171 | case NFT_CT_SRC: |
| 172 | case NFT_CT_DST: |
| 173 | case NFT_CT_PROTO_SRC: |
| 174 | case NFT_CT_PROTO_DST: |
| 175 | if (tb[NFTA_CT_DIRECTION] == NULL) |
| 176 | return -EINVAL; |
| 177 | break; |
| 178 | default: |
| 179 | return -EOPNOTSUPP; |
| 180 | } |
| 181 | |
| 182 | err = nf_ct_l3proto_try_module_get(ctx->afi->family); |
| 183 | if (err < 0) |
| 184 | return err; |
| 185 | priv->family = ctx->afi->family; |
| 186 | |
| 187 | priv->dreg = ntohl(nla_get_be32(tb[NFTA_CT_DREG])); |
| 188 | err = nft_validate_output_register(priv->dreg); |
| 189 | if (err < 0) |
| 190 | goto err1; |
| 191 | |
| 192 | err = nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE); |
| 193 | if (err < 0) |
| 194 | goto err1; |
| 195 | return 0; |
| 196 | |
| 197 | err1: |
| 198 | nf_ct_l3proto_module_put(ctx->afi->family); |
| 199 | return err; |
| 200 | } |
| 201 | |
| 202 | static void nft_ct_destroy(const struct nft_expr *expr) |
| 203 | { |
| 204 | struct nft_ct *priv = nft_expr_priv(expr); |
| 205 | |
| 206 | nf_ct_l3proto_module_put(priv->family); |
| 207 | } |
| 208 | |
| 209 | static int nft_ct_dump(struct sk_buff *skb, const struct nft_expr *expr) |
| 210 | { |
| 211 | const struct nft_ct *priv = nft_expr_priv(expr); |
| 212 | |
| 213 | if (nla_put_be32(skb, NFTA_CT_DREG, htonl(priv->dreg))) |
| 214 | goto nla_put_failure; |
| 215 | if (nla_put_be32(skb, NFTA_CT_KEY, htonl(priv->key))) |
| 216 | goto nla_put_failure; |
| 217 | if (nla_put_u8(skb, NFTA_CT_DIRECTION, priv->dir)) |
| 218 | goto nla_put_failure; |
| 219 | return 0; |
| 220 | |
| 221 | nla_put_failure: |
| 222 | return -1; |
| 223 | } |
| 224 | |
| 225 | static struct nft_expr_type nft_ct_type; |
| 226 | static const struct nft_expr_ops nft_ct_ops = { |
| 227 | .type = &nft_ct_type, |
| 228 | .size = NFT_EXPR_SIZE(sizeof(struct nft_ct)), |
| 229 | .eval = nft_ct_eval, |
| 230 | .init = nft_ct_init, |
| 231 | .destroy = nft_ct_destroy, |
| 232 | .dump = nft_ct_dump, |
| 233 | }; |
| 234 | |
| 235 | static struct nft_expr_type nft_ct_type __read_mostly = { |
| 236 | .name = "ct", |
| 237 | .ops = &nft_ct_ops, |
| 238 | .policy = nft_ct_policy, |
| 239 | .maxattr = NFTA_CT_MAX, |
| 240 | .owner = THIS_MODULE, |
| 241 | }; |
| 242 | |
| 243 | static int __init nft_ct_module_init(void) |
| 244 | { |
| 245 | return nft_register_expr(&nft_ct_type); |
| 246 | } |
| 247 | |
| 248 | static void __exit nft_ct_module_exit(void) |
| 249 | { |
| 250 | nft_unregister_expr(&nft_ct_type); |
| 251 | } |
| 252 | |
| 253 | module_init(nft_ct_module_init); |
| 254 | module_exit(nft_ct_module_exit); |
| 255 | |
| 256 | MODULE_LICENSE("GPL"); |
| 257 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |
| 258 | MODULE_ALIAS_NFT_EXPR("ct"); |