1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> 4 * 5 * Development of this code funded by Astaro AG (http://www.astaro.com/) 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/init.h> 10 #include <linux/module.h> 11 #include <linux/netlink.h> 12 #include <linux/netfilter.h> 13 #include <linux/if_arp.h> 14 #include <linux/netfilter/nf_tables.h> 15 #include <net/netfilter/nf_tables_core.h> 16 #include <net/netfilter/nf_tables_offload.h> 17 #include <net/netfilter/nf_tables.h> 18 19 struct nft_cmp_expr { 20 struct nft_data data; 21 enum nft_registers sreg:8; 22 u8 len; 23 enum nft_cmp_ops op:8; 24 }; 25 26 void nft_cmp_eval(const struct nft_expr *expr, 27 struct nft_regs *regs, 28 const struct nft_pktinfo *pkt) 29 { 30 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 31 int d; 32 33 d = memcmp(®s->data[priv->sreg], &priv->data, priv->len); 34 switch (priv->op) { 35 case NFT_CMP_EQ: 36 if (d != 0) 37 goto mismatch; 38 break; 39 case NFT_CMP_NEQ: 40 if (d == 0) 41 goto mismatch; 42 break; 43 case NFT_CMP_LT: 44 if (d == 0) 45 goto mismatch; 46 /* fall through */ 47 case NFT_CMP_LTE: 48 if (d > 0) 49 goto mismatch; 50 break; 51 case NFT_CMP_GT: 52 if (d == 0) 53 goto mismatch; 54 /* fall through */ 55 case NFT_CMP_GTE: 56 if (d < 0) 57 goto mismatch; 58 break; 59 } 60 return; 61 62 mismatch: 63 regs->verdict.code = NFT_BREAK; 64 } 65 66 static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = { 67 [NFTA_CMP_SREG] = { .type = NLA_U32 }, 68 [NFTA_CMP_OP] = { .type = NLA_U32 }, 69 [NFTA_CMP_DATA] = { .type = NLA_NESTED }, 70 }; 71 72 static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr, 73 const struct nlattr * const tb[]) 74 { 75 struct nft_cmp_expr *priv = nft_expr_priv(expr); 76 struct nft_data_desc desc; 77 int err; 78 79 err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc, 80 tb[NFTA_CMP_DATA]); 81 if (err < 0) 82 return err; 83 84 if (desc.type != NFT_DATA_VALUE) { 85 err = -EINVAL; 86 nft_data_release(&priv->data, desc.type); 87 return err; 88 } 89 90 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 91 err = nft_validate_register_load(priv->sreg, desc.len); 92 if (err < 0) 93 return err; 94 95 priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 96 priv->len = desc.len; 97 return 0; 98 } 99 100 static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) 101 { 102 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 103 104 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 105 goto nla_put_failure; 106 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) 107 goto nla_put_failure; 108 109 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, 110 NFT_DATA_VALUE, priv->len) < 0) 111 goto nla_put_failure; 112 return 0; 113 114 nla_put_failure: 115 return -1; 116 } 117 118 static int __nft_cmp_offload(struct nft_offload_ctx *ctx, 119 struct nft_flow_rule *flow, 120 const struct nft_cmp_expr *priv) 121 { 122 struct nft_offload_reg *reg = &ctx->regs[priv->sreg]; 123 u8 *mask = (u8 *)&flow->match.mask; 124 u8 *key = (u8 *)&flow->match.key; 125 126 if (priv->op != NFT_CMP_EQ || reg->len != priv->len) 127 return -EOPNOTSUPP; 128 129 memcpy(key + reg->offset, &priv->data, priv->len); 130 memcpy(mask + reg->offset, ®->mask, priv->len); 131 132 flow->match.dissector.used_keys |= BIT(reg->key); 133 flow->match.dissector.offset[reg->key] = reg->base_offset; 134 135 if (reg->key == FLOW_DISSECTOR_KEY_META && 136 reg->offset == offsetof(struct nft_flow_key, meta.ingress_iftype) && 137 nft_reg_load16(priv->data.data) != ARPHRD_ETHER) 138 return -EOPNOTSUPP; 139 140 nft_offload_update_dependency(ctx, &priv->data, priv->len); 141 142 return 0; 143 } 144 145 static int nft_cmp_offload(struct nft_offload_ctx *ctx, 146 struct nft_flow_rule *flow, 147 const struct nft_expr *expr) 148 { 149 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 150 151 return __nft_cmp_offload(ctx, flow, priv); 152 } 153 154 static const struct nft_expr_ops nft_cmp_ops = { 155 .type = &nft_cmp_type, 156 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), 157 .eval = nft_cmp_eval, 158 .init = nft_cmp_init, 159 .dump = nft_cmp_dump, 160 .offload = nft_cmp_offload, 161 }; 162 163 static int nft_cmp_fast_init(const struct nft_ctx *ctx, 164 const struct nft_expr *expr, 165 const struct nlattr * const tb[]) 166 { 167 struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 168 struct nft_data_desc desc; 169 struct nft_data data; 170 u32 mask; 171 int err; 172 173 err = nft_data_init(NULL, &data, sizeof(data), &desc, 174 tb[NFTA_CMP_DATA]); 175 if (err < 0) 176 return err; 177 178 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 179 err = nft_validate_register_load(priv->sreg, desc.len); 180 if (err < 0) 181 return err; 182 183 desc.len *= BITS_PER_BYTE; 184 mask = nft_cmp_fast_mask(desc.len); 185 186 priv->data = data.data[0] & mask; 187 priv->len = desc.len; 188 return 0; 189 } 190 191 static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx, 192 struct nft_flow_rule *flow, 193 const struct nft_expr *expr) 194 { 195 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 196 struct nft_cmp_expr cmp = { 197 .data = { 198 .data = { 199 [0] = priv->data, 200 }, 201 }, 202 .sreg = priv->sreg, 203 .len = priv->len / BITS_PER_BYTE, 204 .op = NFT_CMP_EQ, 205 }; 206 207 return __nft_cmp_offload(ctx, flow, &cmp); 208 } 209 210 static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) 211 { 212 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 213 struct nft_data data; 214 215 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 216 goto nla_put_failure; 217 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ))) 218 goto nla_put_failure; 219 220 data.data[0] = priv->data; 221 if (nft_data_dump(skb, NFTA_CMP_DATA, &data, 222 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) 223 goto nla_put_failure; 224 return 0; 225 226 nla_put_failure: 227 return -1; 228 } 229 230 const struct nft_expr_ops nft_cmp_fast_ops = { 231 .type = &nft_cmp_type, 232 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), 233 .eval = NULL, /* inlined */ 234 .init = nft_cmp_fast_init, 235 .dump = nft_cmp_fast_dump, 236 .offload = nft_cmp_fast_offload, 237 }; 238 239 static const struct nft_expr_ops * 240 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 241 { 242 struct nft_data_desc desc; 243 struct nft_data data; 244 enum nft_cmp_ops op; 245 int err; 246 247 if (tb[NFTA_CMP_SREG] == NULL || 248 tb[NFTA_CMP_OP] == NULL || 249 tb[NFTA_CMP_DATA] == NULL) 250 return ERR_PTR(-EINVAL); 251 252 op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 253 switch (op) { 254 case NFT_CMP_EQ: 255 case NFT_CMP_NEQ: 256 case NFT_CMP_LT: 257 case NFT_CMP_LTE: 258 case NFT_CMP_GT: 259 case NFT_CMP_GTE: 260 break; 261 default: 262 return ERR_PTR(-EINVAL); 263 } 264 265 err = nft_data_init(NULL, &data, sizeof(data), &desc, 266 tb[NFTA_CMP_DATA]); 267 if (err < 0) 268 return ERR_PTR(err); 269 270 if (desc.type != NFT_DATA_VALUE) { 271 err = -EINVAL; 272 goto err1; 273 } 274 275 if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) 276 return &nft_cmp_fast_ops; 277 278 return &nft_cmp_ops; 279 err1: 280 nft_data_release(&data, desc.type); 281 return ERR_PTR(-EINVAL); 282 } 283 284 struct nft_expr_type nft_cmp_type __read_mostly = { 285 .name = "cmp", 286 .select_ops = nft_cmp_select_ops, 287 .policy = nft_cmp_policy, 288 .maxattr = NFTA_CMP_MAX, 289 .owner = THIS_MODULE, 290 }; 291