1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
5 * Development of this code funded by Astaro AG (http://www.astaro.com/)
8 #include <asm/unaligned.h>
9 #include <linux/kernel.h>
10 #include <linux/netlink.h>
11 #include <linux/netfilter.h>
12 #include <linux/netfilter/nf_tables.h>
13 #include <net/netfilter/nf_tables_core.h>
14 #include <net/netfilter/nf_tables.h>
22 enum nft_registers dreg:8;
23 enum nft_registers sreg:8;
27 static unsigned int optlen(const u8 *opt, unsigned int offset)
29 /* Beware zero-length options: make finite progress */
30 if (opt[offset] <= TCPOPT_NOP || opt[offset + 1] == 0)
33 return opt[offset + 1];
36 static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
37 struct nft_regs *regs,
38 const struct nft_pktinfo *pkt)
40 struct nft_exthdr *priv = nft_expr_priv(expr);
41 u32 *dest = ®s->data[priv->dreg];
42 unsigned int offset = 0;
45 err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
46 if (priv->flags & NFT_EXTHDR_F_PRESENT) {
52 offset += priv->offset;
54 dest[priv->len / NFT_REG32_SIZE] = 0;
55 if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0)
59 regs->verdict.code = NFT_BREAK;
63 nft_tcp_header_pointer(const struct nft_pktinfo *pkt,
64 unsigned int len, void *buffer, unsigned int *tcphdr_len)
68 if (!pkt->tprot_set || pkt->tprot != IPPROTO_TCP)
71 tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, sizeof(*tcph), buffer);
75 *tcphdr_len = __tcp_hdrlen(tcph);
76 if (*tcphdr_len < sizeof(*tcph) || *tcphdr_len > len)
79 return skb_header_pointer(pkt->skb, pkt->xt.thoff, *tcphdr_len, buffer);
82 static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
83 struct nft_regs *regs,
84 const struct nft_pktinfo *pkt)
86 u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
87 struct nft_exthdr *priv = nft_expr_priv(expr);
88 unsigned int i, optl, tcphdr_len, offset;
89 u32 *dest = ®s->data[priv->dreg];
93 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
98 for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
99 optl = optlen(opt, i);
101 if (priv->type != opt[i])
104 if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
107 offset = i + priv->offset;
108 if (priv->flags & NFT_EXTHDR_F_PRESENT) {
111 dest[priv->len / NFT_REG32_SIZE] = 0;
112 memcpy(dest, opt + offset, priv->len);
119 if (priv->flags & NFT_EXTHDR_F_PRESENT)
122 regs->verdict.code = NFT_BREAK;
125 static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
126 struct nft_regs *regs,
127 const struct nft_pktinfo *pkt)
129 u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
130 struct nft_exthdr *priv = nft_expr_priv(expr);
131 unsigned int i, optl, tcphdr_len, offset;
136 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
141 for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
148 optl = optlen(opt, i);
150 if (priv->type != opt[i])
153 if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
156 if (!skb_make_writable(pkt->skb, pkt->xt.thoff + i + priv->len))
159 tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff,
164 src = regs->data[priv->sreg];
165 offset = i + priv->offset;
169 old.v16 = get_unaligned((u16 *)(opt + offset));
172 switch (priv->type) {
174 /* increase can cause connection to stall */
175 if (ntohs(old.v16) <= ntohs(new.v16))
180 if (old.v16 == new.v16)
183 put_unaligned(new.v16, (u16*)(opt + offset));
184 inet_proto_csum_replace2(&tcph->check, pkt->skb,
185 old.v16, new.v16, false);
189 old.v32 = get_unaligned((u32 *)(opt + offset));
191 if (old.v32 == new.v32)
194 put_unaligned(new.v32, (u32*)(opt + offset));
195 inet_proto_csum_replace4(&tcph->check, pkt->skb,
196 old.v32, new.v32, false);
207 static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
208 [NFTA_EXTHDR_DREG] = { .type = NLA_U32 },
209 [NFTA_EXTHDR_TYPE] = { .type = NLA_U8 },
210 [NFTA_EXTHDR_OFFSET] = { .type = NLA_U32 },
211 [NFTA_EXTHDR_LEN] = { .type = NLA_U32 },
212 [NFTA_EXTHDR_FLAGS] = { .type = NLA_U32 },
213 [NFTA_EXTHDR_OP] = { .type = NLA_U32 },
214 [NFTA_EXTHDR_SREG] = { .type = NLA_U32 },
217 static int nft_exthdr_init(const struct nft_ctx *ctx,
218 const struct nft_expr *expr,
219 const struct nlattr * const tb[])
221 struct nft_exthdr *priv = nft_expr_priv(expr);
222 u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
225 if (!tb[NFTA_EXTHDR_DREG] ||
226 !tb[NFTA_EXTHDR_TYPE] ||
227 !tb[NFTA_EXTHDR_OFFSET] ||
228 !tb[NFTA_EXTHDR_LEN])
231 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
235 err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
239 if (tb[NFTA_EXTHDR_FLAGS]) {
240 err = nft_parse_u32_check(tb[NFTA_EXTHDR_FLAGS], U8_MAX, &flags);
244 if (flags & ~NFT_EXTHDR_F_PRESENT)
248 if (tb[NFTA_EXTHDR_OP]) {
249 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
254 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
255 priv->offset = offset;
257 priv->dreg = nft_parse_register(tb[NFTA_EXTHDR_DREG]);
261 return nft_validate_register_store(ctx, priv->dreg, NULL,
262 NFT_DATA_VALUE, priv->len);
265 static int nft_exthdr_tcp_set_init(const struct nft_ctx *ctx,
266 const struct nft_expr *expr,
267 const struct nlattr * const tb[])
269 struct nft_exthdr *priv = nft_expr_priv(expr);
270 u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
273 if (!tb[NFTA_EXTHDR_SREG] ||
274 !tb[NFTA_EXTHDR_TYPE] ||
275 !tb[NFTA_EXTHDR_OFFSET] ||
276 !tb[NFTA_EXTHDR_LEN])
279 if (tb[NFTA_EXTHDR_DREG] || tb[NFTA_EXTHDR_FLAGS])
282 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
286 err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
300 err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
304 priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
305 priv->offset = offset;
307 priv->sreg = nft_parse_register(tb[NFTA_EXTHDR_SREG]);
311 return nft_validate_register_load(priv->sreg, priv->len);
314 static int nft_exthdr_dump_common(struct sk_buff *skb, const struct nft_exthdr *priv)
316 if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
317 goto nla_put_failure;
318 if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
319 goto nla_put_failure;
320 if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
321 goto nla_put_failure;
322 if (nla_put_be32(skb, NFTA_EXTHDR_FLAGS, htonl(priv->flags)))
323 goto nla_put_failure;
324 if (nla_put_be32(skb, NFTA_EXTHDR_OP, htonl(priv->op)))
325 goto nla_put_failure;
332 static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
334 const struct nft_exthdr *priv = nft_expr_priv(expr);
336 if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg))
339 return nft_exthdr_dump_common(skb, priv);
342 static int nft_exthdr_dump_set(struct sk_buff *skb, const struct nft_expr *expr)
344 const struct nft_exthdr *priv = nft_expr_priv(expr);
346 if (nft_dump_register(skb, NFTA_EXTHDR_SREG, priv->sreg))
349 return nft_exthdr_dump_common(skb, priv);
352 static const struct nft_expr_ops nft_exthdr_ipv6_ops = {
353 .type = &nft_exthdr_type,
354 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
355 .eval = nft_exthdr_ipv6_eval,
356 .init = nft_exthdr_init,
357 .dump = nft_exthdr_dump,
360 static const struct nft_expr_ops nft_exthdr_tcp_ops = {
361 .type = &nft_exthdr_type,
362 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
363 .eval = nft_exthdr_tcp_eval,
364 .init = nft_exthdr_init,
365 .dump = nft_exthdr_dump,
368 static const struct nft_expr_ops nft_exthdr_tcp_set_ops = {
369 .type = &nft_exthdr_type,
370 .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
371 .eval = nft_exthdr_tcp_set_eval,
372 .init = nft_exthdr_tcp_set_init,
373 .dump = nft_exthdr_dump_set,
376 static const struct nft_expr_ops *
377 nft_exthdr_select_ops(const struct nft_ctx *ctx,
378 const struct nlattr * const tb[])
382 if (!tb[NFTA_EXTHDR_OP])
383 return &nft_exthdr_ipv6_ops;
385 if (tb[NFTA_EXTHDR_SREG] && tb[NFTA_EXTHDR_DREG])
386 return ERR_PTR(-EOPNOTSUPP);
388 op = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OP]));
390 case NFT_EXTHDR_OP_TCPOPT:
391 if (tb[NFTA_EXTHDR_SREG])
392 return &nft_exthdr_tcp_set_ops;
393 if (tb[NFTA_EXTHDR_DREG])
394 return &nft_exthdr_tcp_ops;
396 case NFT_EXTHDR_OP_IPV6:
397 if (tb[NFTA_EXTHDR_DREG])
398 return &nft_exthdr_ipv6_ops;
402 return ERR_PTR(-EOPNOTSUPP);
405 struct nft_expr_type nft_exthdr_type __read_mostly = {
407 .select_ops = nft_exthdr_select_ops,
408 .policy = nft_exthdr_policy,
409 .maxattr = NFTA_EXTHDR_MAX,
410 .owner = THIS_MODULE,