1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2022 Pablo Neira Ayuso <pablo@netfilter.org>
4 */
5
6 #include <linux/kernel.h>
7 #include <linux/if_vlan.h>
8 #include <linux/init.h>
9 #include <linux/module.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>
15 #include <net/netfilter/nft_meta.h>
16 #include <net/netfilter/nf_tables_offload.h>
17 #include <linux/tcp.h>
18 #include <linux/udp.h>
19 #include <net/gre.h>
20 #include <net/geneve.h>
21 #include <net/ip.h>
22 #include <linux/icmpv6.h>
23 #include <linux/ip.h>
24 #include <linux/ipv6.h>
25
26 static DEFINE_PER_CPU(struct nft_inner_tun_ctx, nft_pcpu_tun_ctx);
27
28 /* Same layout as nft_expr but it embeds the private expression data area. */
29 struct __nft_expr {
30 const struct nft_expr_ops *ops;
31 union {
32 struct nft_payload payload;
33 struct nft_meta meta;
34 } __attribute__((aligned(__alignof__(u64))));
35 };
36
37 enum {
38 NFT_INNER_EXPR_PAYLOAD,
39 NFT_INNER_EXPR_META,
40 };
41
42 struct nft_inner {
43 u8 flags;
44 u8 hdrsize;
45 u8 type;
46 u8 expr_type;
47
48 struct __nft_expr expr;
49 };
50
nft_inner_parse_l2l3(const struct nft_inner * priv,const struct nft_pktinfo * pkt,struct nft_inner_tun_ctx * ctx,u32 off)51 static int nft_inner_parse_l2l3(const struct nft_inner *priv,
52 const struct nft_pktinfo *pkt,
53 struct nft_inner_tun_ctx *ctx, u32 off)
54 {
55 __be16 llproto, outer_llproto;
56 u32 nhoff, thoff;
57
58 if (priv->flags & NFT_INNER_LL) {
59 struct vlan_ethhdr *veth, _veth;
60 struct ethhdr *eth, _eth;
61 u32 hdrsize;
62
63 eth = skb_header_pointer(pkt->skb, off, sizeof(_eth), &_eth);
64 if (!eth)
65 return -1;
66
67 switch (eth->h_proto) {
68 case htons(ETH_P_IP):
69 case htons(ETH_P_IPV6):
70 llproto = eth->h_proto;
71 hdrsize = sizeof(_eth);
72 break;
73 case htons(ETH_P_8021Q):
74 veth = skb_header_pointer(pkt->skb, off, sizeof(_veth), &_veth);
75 if (!veth)
76 return -1;
77
78 outer_llproto = veth->h_vlan_encapsulated_proto;
79 llproto = veth->h_vlan_proto;
80 hdrsize = sizeof(_veth);
81 break;
82 default:
83 return -1;
84 }
85
86 ctx->inner_lloff = off;
87 ctx->flags |= NFT_PAYLOAD_CTX_INNER_LL;
88 off += hdrsize;
89 } else {
90 struct iphdr *iph;
91 u32 _version;
92
93 iph = skb_header_pointer(pkt->skb, off, sizeof(_version), &_version);
94 if (!iph)
95 return -1;
96
97 switch (iph->version) {
98 case 4:
99 llproto = htons(ETH_P_IP);
100 break;
101 case 6:
102 llproto = htons(ETH_P_IPV6);
103 break;
104 default:
105 return -1;
106 }
107 }
108
109 ctx->llproto = llproto;
110 if (llproto == htons(ETH_P_8021Q))
111 llproto = outer_llproto;
112
113 nhoff = off;
114
115 switch (llproto) {
116 case htons(ETH_P_IP): {
117 struct iphdr *iph, _iph;
118
119 iph = skb_header_pointer(pkt->skb, nhoff, sizeof(_iph), &_iph);
120 if (!iph)
121 return -1;
122
123 if (iph->ihl < 5 || iph->version != 4)
124 return -1;
125
126 ctx->inner_nhoff = nhoff;
127 ctx->flags |= NFT_PAYLOAD_CTX_INNER_NH;
128
129 thoff = nhoff + (iph->ihl * 4);
130 if ((ntohs(iph->frag_off) & IP_OFFSET) == 0) {
131 ctx->flags |= NFT_PAYLOAD_CTX_INNER_TH;
132 ctx->inner_thoff = thoff;
133 ctx->l4proto = iph->protocol;
134 }
135 }
136 break;
137 case htons(ETH_P_IPV6): {
138 struct ipv6hdr *ip6h, _ip6h;
139 int fh_flags = IP6_FH_F_AUTH;
140 unsigned short fragoff;
141 int l4proto;
142
143 ip6h = skb_header_pointer(pkt->skb, nhoff, sizeof(_ip6h), &_ip6h);
144 if (!ip6h)
145 return -1;
146
147 if (ip6h->version != 6)
148 return -1;
149
150 ctx->inner_nhoff = nhoff;
151 ctx->flags |= NFT_PAYLOAD_CTX_INNER_NH;
152
153 thoff = nhoff;
154 l4proto = ipv6_find_hdr(pkt->skb, &thoff, -1, &fragoff, &fh_flags);
155 if (l4proto < 0 || thoff > U16_MAX)
156 return -1;
157
158 if (fragoff == 0) {
159 thoff = nhoff + sizeof(_ip6h);
160 ctx->flags |= NFT_PAYLOAD_CTX_INNER_TH;
161 ctx->inner_thoff = thoff;
162 ctx->l4proto = l4proto;
163 }
164 }
165 break;
166 default:
167 return -1;
168 }
169
170 return 0;
171 }
172
nft_inner_parse_tunhdr(const struct nft_inner * priv,const struct nft_pktinfo * pkt,struct nft_inner_tun_ctx * ctx,u32 * off)173 static int nft_inner_parse_tunhdr(const struct nft_inner *priv,
174 const struct nft_pktinfo *pkt,
175 struct nft_inner_tun_ctx *ctx, u32 *off)
176 {
177 if (pkt->tprot == IPPROTO_GRE) {
178 ctx->inner_tunoff = pkt->thoff;
179 ctx->flags |= NFT_PAYLOAD_CTX_INNER_TUN;
180 return 0;
181 }
182
183 if (pkt->tprot != IPPROTO_UDP)
184 return -1;
185
186 ctx->inner_tunoff = *off;
187 ctx->flags |= NFT_PAYLOAD_CTX_INNER_TUN;
188 *off += priv->hdrsize;
189
190 switch (priv->type) {
191 case NFT_INNER_GENEVE: {
192 struct genevehdr *gnvh, _gnvh;
193
194 gnvh = skb_header_pointer(pkt->skb, pkt->inneroff,
195 sizeof(_gnvh), &_gnvh);
196 if (!gnvh)
197 return -1;
198
199 *off += gnvh->opt_len * 4;
200 }
201 break;
202 default:
203 break;
204 }
205
206 return 0;
207 }
208
nft_inner_parse(const struct nft_inner * priv,struct nft_pktinfo * pkt,struct nft_inner_tun_ctx * tun_ctx)209 static int nft_inner_parse(const struct nft_inner *priv,
210 struct nft_pktinfo *pkt,
211 struct nft_inner_tun_ctx *tun_ctx)
212 {
213 struct nft_inner_tun_ctx ctx = {};
214 u32 off = pkt->inneroff;
215
216 if (priv->flags & NFT_INNER_HDRSIZE &&
217 nft_inner_parse_tunhdr(priv, pkt, &ctx, &off) < 0)
218 return -1;
219
220 if (priv->flags & (NFT_INNER_LL | NFT_INNER_NH)) {
221 if (nft_inner_parse_l2l3(priv, pkt, &ctx, off) < 0)
222 return -1;
223 } else if (priv->flags & NFT_INNER_TH) {
224 ctx.inner_thoff = off;
225 ctx.flags |= NFT_PAYLOAD_CTX_INNER_TH;
226 }
227
228 *tun_ctx = ctx;
229 tun_ctx->type = priv->type;
230 pkt->flags |= NFT_PKTINFO_INNER_FULL;
231
232 return 0;
233 }
234
nft_inner_parse_needed(const struct nft_inner * priv,const struct nft_pktinfo * pkt,const struct nft_inner_tun_ctx * tun_ctx)235 static bool nft_inner_parse_needed(const struct nft_inner *priv,
236 const struct nft_pktinfo *pkt,
237 const struct nft_inner_tun_ctx *tun_ctx)
238 {
239 if (!(pkt->flags & NFT_PKTINFO_INNER_FULL))
240 return true;
241
242 if (priv->type != tun_ctx->type)
243 return true;
244
245 return false;
246 }
247
nft_inner_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)248 static void nft_inner_eval(const struct nft_expr *expr, struct nft_regs *regs,
249 const struct nft_pktinfo *pkt)
250 {
251 struct nft_inner_tun_ctx *tun_ctx = this_cpu_ptr(&nft_pcpu_tun_ctx);
252 const struct nft_inner *priv = nft_expr_priv(expr);
253
254 if (nft_payload_inner_offset(pkt) < 0)
255 goto err;
256
257 if (nft_inner_parse_needed(priv, pkt, tun_ctx) &&
258 nft_inner_parse(priv, (struct nft_pktinfo *)pkt, tun_ctx) < 0)
259 goto err;
260
261 switch (priv->expr_type) {
262 case NFT_INNER_EXPR_PAYLOAD:
263 nft_payload_inner_eval((struct nft_expr *)&priv->expr, regs, pkt, tun_ctx);
264 break;
265 case NFT_INNER_EXPR_META:
266 nft_meta_inner_eval((struct nft_expr *)&priv->expr, regs, pkt, tun_ctx);
267 break;
268 default:
269 WARN_ON_ONCE(1);
270 goto err;
271 }
272 return;
273 err:
274 regs->verdict.code = NFT_BREAK;
275 }
276
277 static const struct nla_policy nft_inner_policy[NFTA_INNER_MAX + 1] = {
278 [NFTA_INNER_NUM] = { .type = NLA_U32 },
279 [NFTA_INNER_FLAGS] = { .type = NLA_U32 },
280 [NFTA_INNER_HDRSIZE] = { .type = NLA_U32 },
281 [NFTA_INNER_TYPE] = { .type = NLA_U32 },
282 [NFTA_INNER_EXPR] = { .type = NLA_NESTED },
283 };
284
285 struct nft_expr_info {
286 const struct nft_expr_ops *ops;
287 const struct nlattr *attr;
288 struct nlattr *tb[NFT_EXPR_MAXATTR + 1];
289 };
290
nft_inner_init(const struct nft_ctx * ctx,const struct nft_expr * expr,const struct nlattr * const tb[])291 static int nft_inner_init(const struct nft_ctx *ctx,
292 const struct nft_expr *expr,
293 const struct nlattr * const tb[])
294 {
295 struct nft_inner *priv = nft_expr_priv(expr);
296 u32 flags, hdrsize, type, num;
297 struct nft_expr_info expr_info;
298 int err;
299
300 if (!tb[NFTA_INNER_FLAGS] ||
301 !tb[NFTA_INNER_NUM] ||
302 !tb[NFTA_INNER_HDRSIZE] ||
303 !tb[NFTA_INNER_TYPE] ||
304 !tb[NFTA_INNER_EXPR])
305 return -EINVAL;
306
307 flags = ntohl(nla_get_be32(tb[NFTA_INNER_FLAGS]));
308 if (flags & ~NFT_INNER_MASK)
309 return -EOPNOTSUPP;
310
311 num = ntohl(nla_get_be32(tb[NFTA_INNER_NUM]));
312 if (num != 0)
313 return -EOPNOTSUPP;
314
315 hdrsize = ntohl(nla_get_be32(tb[NFTA_INNER_HDRSIZE]));
316 type = ntohl(nla_get_be32(tb[NFTA_INNER_TYPE]));
317
318 if (type > U8_MAX)
319 return -EINVAL;
320
321 if (flags & NFT_INNER_HDRSIZE) {
322 if (hdrsize == 0 || hdrsize > 64)
323 return -EOPNOTSUPP;
324 }
325
326 priv->flags = flags;
327 priv->hdrsize = hdrsize;
328 priv->type = type;
329
330 err = nft_expr_inner_parse(ctx, tb[NFTA_INNER_EXPR], &expr_info);
331 if (err < 0)
332 return err;
333
334 priv->expr.ops = expr_info.ops;
335
336 if (!strcmp(expr_info.ops->type->name, "payload"))
337 priv->expr_type = NFT_INNER_EXPR_PAYLOAD;
338 else if (!strcmp(expr_info.ops->type->name, "meta"))
339 priv->expr_type = NFT_INNER_EXPR_META;
340 else
341 return -EINVAL;
342
343 err = expr_info.ops->init(ctx, (struct nft_expr *)&priv->expr,
344 (const struct nlattr * const*)expr_info.tb);
345 if (err < 0)
346 return err;
347
348 return 0;
349 }
350
nft_inner_dump(struct sk_buff * skb,const struct nft_expr * expr,bool reset)351 static int nft_inner_dump(struct sk_buff *skb,
352 const struct nft_expr *expr, bool reset)
353 {
354 const struct nft_inner *priv = nft_expr_priv(expr);
355
356 if (nla_put_be32(skb, NFTA_INNER_NUM, htonl(0)) ||
357 nla_put_be32(skb, NFTA_INNER_TYPE, htonl(priv->type)) ||
358 nla_put_be32(skb, NFTA_INNER_FLAGS, htonl(priv->flags)) ||
359 nla_put_be32(skb, NFTA_INNER_HDRSIZE, htonl(priv->hdrsize)))
360 goto nla_put_failure;
361
362 if (nft_expr_dump(skb, NFTA_INNER_EXPR,
363 (struct nft_expr *)&priv->expr, reset) < 0)
364 goto nla_put_failure;
365
366 return 0;
367
368 nla_put_failure:
369 return -1;
370 }
371
372 static const struct nft_expr_ops nft_inner_ops = {
373 .type = &nft_inner_type,
374 .size = NFT_EXPR_SIZE(sizeof(struct nft_inner)),
375 .eval = nft_inner_eval,
376 .init = nft_inner_init,
377 .dump = nft_inner_dump,
378 };
379
380 struct nft_expr_type nft_inner_type __read_mostly = {
381 .name = "inner",
382 .ops = &nft_inner_ops,
383 .policy = nft_inner_policy,
384 .maxattr = NFTA_INNER_MAX,
385 .owner = THIS_MODULE,
386 };
387
