1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2008-2009 Patrick McHardy <[email protected]> 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 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 85 err = nft_validate_register_load(priv->sreg, desc.len); 86 if (err < 0) 87 return err; 88 89 priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 90 priv->len = desc.len; 91 return 0; 92 } 93 94 static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr) 95 { 96 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 97 98 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 99 goto nla_put_failure; 100 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op))) 101 goto nla_put_failure; 102 103 if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data, 104 NFT_DATA_VALUE, priv->len) < 0) 105 goto nla_put_failure; 106 return 0; 107 108 nla_put_failure: 109 return -1; 110 } 111 112 static int __nft_cmp_offload(struct nft_offload_ctx *ctx, 113 struct nft_flow_rule *flow, 114 const struct nft_cmp_expr *priv) 115 { 116 struct nft_offload_reg *reg = &ctx->regs[priv->sreg]; 117 u8 *mask = (u8 *)&flow->match.mask; 118 u8 *key = (u8 *)&flow->match.key; 119 120 if (priv->op != NFT_CMP_EQ || reg->len != priv->len) 121 return -EOPNOTSUPP; 122 123 memcpy(key + reg->offset, &priv->data, priv->len); 124 memcpy(mask + reg->offset, ®->mask, priv->len); 125 126 flow->match.dissector.used_keys |= BIT(reg->key); 127 flow->match.dissector.offset[reg->key] = reg->base_offset; 128 129 if (reg->key == FLOW_DISSECTOR_KEY_META && 130 reg->offset == offsetof(struct nft_flow_key, meta.ingress_iftype) && 131 nft_reg_load16(priv->data.data) != ARPHRD_ETHER) 132 return -EOPNOTSUPP; 133 134 nft_offload_update_dependency(ctx, &priv->data, priv->len); 135 136 return 0; 137 } 138 139 static int nft_cmp_offload(struct nft_offload_ctx *ctx, 140 struct nft_flow_rule *flow, 141 const struct nft_expr *expr) 142 { 143 const struct nft_cmp_expr *priv = nft_expr_priv(expr); 144 145 return __nft_cmp_offload(ctx, flow, priv); 146 } 147 148 static const struct nft_expr_ops nft_cmp_ops = { 149 .type = &nft_cmp_type, 150 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)), 151 .eval = nft_cmp_eval, 152 .init = nft_cmp_init, 153 .dump = nft_cmp_dump, 154 .offload = nft_cmp_offload, 155 }; 156 157 static int nft_cmp_fast_init(const struct nft_ctx *ctx, 158 const struct nft_expr *expr, 159 const struct nlattr * const tb[]) 160 { 161 struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 162 struct nft_data_desc desc; 163 struct nft_data data; 164 u32 mask; 165 int err; 166 167 err = nft_data_init(NULL, &data, sizeof(data), &desc, 168 tb[NFTA_CMP_DATA]); 169 if (err < 0) 170 return err; 171 172 priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]); 173 err = nft_validate_register_load(priv->sreg, desc.len); 174 if (err < 0) 175 return err; 176 177 desc.len *= BITS_PER_BYTE; 178 mask = nft_cmp_fast_mask(desc.len); 179 180 priv->data = data.data[0] & mask; 181 priv->len = desc.len; 182 return 0; 183 } 184 185 static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx, 186 struct nft_flow_rule *flow, 187 const struct nft_expr *expr) 188 { 189 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 190 struct nft_cmp_expr cmp = { 191 .data = { 192 .data = { 193 [0] = priv->data, 194 }, 195 }, 196 .sreg = priv->sreg, 197 .len = priv->len / BITS_PER_BYTE, 198 .op = NFT_CMP_EQ, 199 }; 200 201 return __nft_cmp_offload(ctx, flow, &cmp); 202 } 203 204 static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr) 205 { 206 const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr); 207 struct nft_data data; 208 209 if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg)) 210 goto nla_put_failure; 211 if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ))) 212 goto nla_put_failure; 213 214 data.data[0] = priv->data; 215 if (nft_data_dump(skb, NFTA_CMP_DATA, &data, 216 NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0) 217 goto nla_put_failure; 218 return 0; 219 220 nla_put_failure: 221 return -1; 222 } 223 224 const struct nft_expr_ops nft_cmp_fast_ops = { 225 .type = &nft_cmp_type, 226 .size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)), 227 .eval = NULL, /* inlined */ 228 .init = nft_cmp_fast_init, 229 .dump = nft_cmp_fast_dump, 230 .offload = nft_cmp_fast_offload, 231 }; 232 233 static const struct nft_expr_ops * 234 nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[]) 235 { 236 struct nft_data_desc desc; 237 struct nft_data data; 238 enum nft_cmp_ops op; 239 int err; 240 241 if (tb[NFTA_CMP_SREG] == NULL || 242 tb[NFTA_CMP_OP] == NULL || 243 tb[NFTA_CMP_DATA] == NULL) 244 return ERR_PTR(-EINVAL); 245 246 op = ntohl(nla_get_be32(tb[NFTA_CMP_OP])); 247 switch (op) { 248 case NFT_CMP_EQ: 249 case NFT_CMP_NEQ: 250 case NFT_CMP_LT: 251 case NFT_CMP_LTE: 252 case NFT_CMP_GT: 253 case NFT_CMP_GTE: 254 break; 255 default: 256 return ERR_PTR(-EINVAL); 257 } 258 259 err = nft_data_init(NULL, &data, sizeof(data), &desc, 260 tb[NFTA_CMP_DATA]); 261 if (err < 0) 262 return ERR_PTR(err); 263 264 if (desc.type != NFT_DATA_VALUE) { 265 err = -EINVAL; 266 goto err1; 267 } 268 269 if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ) 270 return &nft_cmp_fast_ops; 271 272 return &nft_cmp_ops; 273 err1: 274 nft_data_release(&data, desc.type); 275 return ERR_PTR(-EINVAL); 276 } 277 278 struct nft_expr_type nft_cmp_type __read_mostly = { 279 .name = "cmp", 280 .select_ops = nft_cmp_select_ops, 281 .policy = nft_cmp_policy, 282 .maxattr = NFTA_CMP_MAX, 283 .owner = THIS_MODULE, 284 }; 285