2 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
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.
8 * Development of this code funded by Astaro AG (http://www.astaro.com/)
11 #include <asm/unaligned.h>
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/netlink.h>
16 #include <linux/netfilter.h>
17 #include <linux/netfilter/nf_tables.h>
18 #include <net/netfilter/nf_tables.h>
26 enum nft_registers dreg:8;
27 enum nft_registers sreg:8;
31 static unsigned int optlen(const u8 *opt, unsigned int offset)
33 /* Beware zero-length options: make finite progress */
34 if (opt[offset] <= TCPOPT_NOP || opt[offset + 1] == 0)
37 return opt[offset + 1];
40 static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
41 struct nft_regs *regs,
42 const struct nft_pktinfo *pkt)
44 struct nft_exthdr *priv = nft_expr_priv(expr);
45 u32 *dest = ®s->data[priv->dreg];
46 unsigned int offset = 0;
49 if (pkt->skb->protocol != htons(ETH_P_IPV6))
52 err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
53 if (priv->flags & NFT_EXTHDR_F_PRESENT) {
59 offset += priv->offset;
61 dest[priv->len / NFT_REG32_SIZE] = 0;
62 if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
66 regs->verdict.code = NFT_BREAK;
70 nft_tcp_header_pointer(const struct nft_pktinfo *pkt,
71 unsigned int len, void *buffer, unsigned int *tcphdr_len)
75 if (!pkt->tprot_set || pkt->tprot != IPPROTO_TCP)
78 tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, sizeof(*tcph), buffer);
82 *tcphdr_len = __tcp_hdrlen(tcph);
83 if (*tcphdr_len < sizeof(*tcph) || *tcphdr_len > len)
86 return skb_header_pointer(pkt->skb, pkt->xt.thoff, *tcphdr_len, buffer);
89 static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
90 struct nft_regs *regs,
91 const struct nft_pktinfo *pkt)
93 u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
94 struct nft_exthdr *priv = nft_expr_priv(expr);
95 unsigned int i, optl, tcphdr_len, offset;
96 u32 *dest = ®s->data[priv->dreg];
100 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
105 for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
106 optl = optlen(opt, i);
108 if (priv->type != opt[i])
111 if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
114 offset = i + priv->offset;
115 if (priv->flags & NFT_EXTHDR_F_PRESENT) {
118 dest[priv->len / NFT_REG32_SIZE] = 0;
119 memcpy(dest, opt + offset, priv->len);
126 if (priv->flags & NFT_EXTHDR_F_PRESENT)
129 regs->verdict.code = NFT_BREAK;
132 static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
133 struct nft_regs *regs,
134 const struct nft_pktinfo *pkt)
136 u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
137 struct nft_exthdr *priv = nft_expr_priv(expr);
138 unsigned int i, optl, tcphdr_len, offset;
142 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
147 for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
153 optl = optlen(opt, i);
155 if (priv->type != opt[i])
158 if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
161 if (!skb_make_writable(pkt->skb, pkt->xt.thoff + i + priv->len))
164 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff,
169 offset = i + priv->offset;
173 old.v16 = get_unaligned((u16 *)(opt + offset));
174 new.v16 = (__force __be16)nft_reg_load16(
175 ®s->data[priv->sreg]);
177 switch (priv->type) {
179 /* increase can cause connection to stall */
180 if (ntohs(old.v16) <= ntohs(new.v16))
185 if (old.v16 == new.v16)
188 put_unaligned(new.v16, (u16*)(opt + offset));
189 inet_proto_csum_replace2(&tcph->check, pkt->skb,
190 old.v16, new.v16, false);
193 new.v32 = regs->data[priv->sreg];
194 old.v32 = get_unaligned((u32 *)(opt + offset));
196 if (old.v32 == new.v32)
199 put_unaligned(new.v32, (u32*)(opt + offset));
200 inet_proto_csum_replace4(&tcph->check, pkt->skb,
201 old.v32, new.v32, false);
212 static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
213 [NFTA_EXTHDR_DREG] = { .type = NLA_U32 },
214 [NFTA_EXTHDR_TYPE] = { .type = NLA_U8 },
215 [NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 },
216 [NFTA_EXTHDR_LEN] = { .type = NLA_U32 },
217 [NFTA_EXTHDR_FLAGS] = { .type = NLA_U32 },
220 static int nft_exthdr_init(const struct nft_ctx *ctx,
221 const struct nft_expr *expr,
222 const struct nlattr * const tb[])
224 struct nft_exthdr *priv = nft_expr_priv(expr);
225 u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
228 if (!tb[NFTA_EXTHDR_DREG] ||
229 !tb[NFTA_EXTHDR_TYPE] ||
230 !tb[NFTA_EXTHDR_OFFSET] ||
231 !tb[NFTA_EXTHDR_LEN])
234 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
238 err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
242 if (tb[NFTA_EXTHDR_FLAGS]) {
243 err = nft_parse_u32_check(tb[NFTA_EXTHDR_FLAGS], U8_MAX, &flags);
247 if (flags & ~NFT_EXTHDR_F_PRESENT)
251 if (tb[NFTA_EXTHDR_OP]) {
252 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
257 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
258 priv->offset = offset;
260 priv->dreg = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
264 return nft_validate_register_store(ctx, priv->dreg, NULL,
265 NFT_DATA_VALUE, priv->len);
268 static int nft_exthdr_tcp_set_init(const struct nft_ctx *ctx,
269 const struct nft_expr *expr,
270 const struct nlattr * const tb[])
272 struct nft_exthdr *priv = nft_expr_priv(expr);
273 u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
276 if (!tb[NFTA_EXTHDR_SREG] ||
277 !tb[NFTA_EXTHDR_TYPE] ||
278 !tb[NFTA_EXTHDR_OFFSET] ||
279 !tb[NFTA_EXTHDR_LEN])
282 if (tb[NFTA_EXTHDR_DREG] || tb[NFTA_EXTHDR_FLAGS])
285 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
289 err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
303 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
307 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
308 priv->offset = offset;
310 priv->sreg = nft_parse_register(tb[NFTA_EXTHDR_SREG]);
314 return nft_validate_register_load(priv->sreg, priv->len);
317 static int nft_exthdr_dump_common(struct sk_buff *skb, const struct nft_exthdr *priv)
319 if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
320 goto nla_put_failure;
321 if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
322 goto nla_put_failure;
323 if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
324 goto nla_put_failure;
325 if (nla_put_be32(skb, NFTA_EXTHDR_FLAGS, htonl(priv->flags)))
326 goto nla_put_failure;
327 if (nla_put_be32(skb, NFTA_EXTHDR_OP, htonl(priv->op)))
328 goto nla_put_failure;
335 static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
337 const struct nft_exthdr *priv = nft_expr_priv(expr);
339 if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg))
342 return nft_exthdr_dump_common(skb, priv);
345 static int nft_exthdr_dump_set(struct sk_buff *skb, const struct nft_expr *expr)
347 const struct nft_exthdr *priv = nft_expr_priv(expr);
349 if (nft_dump_register(skb, NFTA_EXTHDR_SREG, priv->sreg))
352 return nft_exthdr_dump_common(skb, priv);
355 static struct nft_expr_type nft_exthdr_type;
356 static const struct nft_expr_ops nft_exthdr_ipv6_ops = {
357 .type = &nft_exthdr_type,
358 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
359 .eval = nft_exthdr_ipv6_eval,
360 .init = nft_exthdr_init,
361 .dump = nft_exthdr_dump,
364 static const struct nft_expr_ops nft_exthdr_tcp_ops = {
365 .type = &nft_exthdr_type,
366 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
367 .eval = nft_exthdr_tcp_eval,
368 .init = nft_exthdr_init,
369 .dump = nft_exthdr_dump,
372 static const struct nft_expr_ops nft_exthdr_tcp_set_ops = {
373 .type = &nft_exthdr_type,
374 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
375 .eval = nft_exthdr_tcp_set_eval,
376 .init = nft_exthdr_tcp_set_init,
377 .dump = nft_exthdr_dump_set,
380 static const struct nft_expr_ops *
381 nft_exthdr_select_ops(const struct nft_ctx *ctx,
382 const struct nlattr * const tb[])
386 if (!tb[NFTA_EXTHDR_OP])
387 return &nft_exthdr_ipv6_ops;
389 if (tb[NFTA_EXTHDR_SREG] && tb[NFTA_EXTHDR_DREG])
390 return ERR_PTR(-EOPNOTSUPP);
392 op = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OP]));
394 case NFT_EXTHDR_OP_TCPOPT:
395 if (tb[NFTA_EXTHDR_SREG])
396 return &nft_exthdr_tcp_set_ops;
397 if (tb[NFTA_EXTHDR_DREG])
398 return &nft_exthdr_tcp_ops;
400 case NFT_EXTHDR_OP_IPV6:
401 if (tb[NFTA_EXTHDR_DREG])
402 return &nft_exthdr_ipv6_ops;
406 return ERR_PTR(-EOPNOTSUPP);
409 static struct nft_expr_type nft_exthdr_type __read_mostly = {
411 .select_ops = nft_exthdr_select_ops,
412 .policy = nft_exthdr_policy,
413 .maxattr = NFTA_EXTHDR_MAX,
414 .owner = THIS_MODULE,
417 static int __init nft_exthdr_module_init(void)
419 return nft_register_expr(&nft_exthdr_type);
422 static void __exit nft_exthdr_module_exit(void)
424 nft_unregister_expr(&nft_exthdr_type);
427 module_init(nft_exthdr_module_init);
428 module_exit(nft_exthdr_module_exit);
430 MODULE_LICENSE("GPL");
431 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
432 MODULE_ALIAS_NFT_EXPR("exthdr");