1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/netfilter.h>
4 #include <linux/netfilter_ipv4.h>
5 #include <linux/netfilter_ipv6.h>
6 #include <net/netfilter/nf_queue.h>
7 #include <net/ip6_checksum.h>
8
9 #ifdef CONFIG_INET
nf_ip_checksum(struct sk_buff * skb,unsigned int hook,unsigned int dataoff,u8 protocol)10 __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
11 unsigned int dataoff, u8 protocol)
12 {
13 const struct iphdr *iph = ip_hdr(skb);
14 __sum16 csum = 0;
15
16 switch (skb->ip_summed) {
17 case CHECKSUM_COMPLETE:
18 if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
19 break;
20 if ((protocol != IPPROTO_TCP && protocol != IPPROTO_UDP &&
21 !csum_fold(skb->csum)) ||
22 !csum_tcpudp_magic(iph->saddr, iph->daddr,
23 skb->len - dataoff, protocol,
24 skb->csum)) {
25 skb->ip_summed = CHECKSUM_UNNECESSARY;
26 break;
27 }
28 fallthrough;
29 case CHECKSUM_NONE:
30 if (protocol != IPPROTO_TCP && protocol != IPPROTO_UDP)
31 skb->csum = 0;
32 else
33 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
34 skb->len - dataoff,
35 protocol, 0);
36 csum = __skb_checksum_complete(skb);
37 }
38 return csum;
39 }
40 EXPORT_SYMBOL(nf_ip_checksum);
41 #endif
42
nf_ip_checksum_partial(struct sk_buff * skb,unsigned int hook,unsigned int dataoff,unsigned int len,u8 protocol)43 static __sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
44 unsigned int dataoff, unsigned int len,
45 u8 protocol)
46 {
47 const struct iphdr *iph = ip_hdr(skb);
48 __sum16 csum = 0;
49
50 switch (skb->ip_summed) {
51 case CHECKSUM_COMPLETE:
52 if (len == skb->len - dataoff)
53 return nf_ip_checksum(skb, hook, dataoff, protocol);
54 fallthrough;
55 case CHECKSUM_NONE:
56 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, protocol,
57 skb->len - dataoff, 0);
58 skb->ip_summed = CHECKSUM_NONE;
59 return __skb_checksum_complete_head(skb, dataoff + len);
60 }
61 return csum;
62 }
63
nf_ip6_checksum(struct sk_buff * skb,unsigned int hook,unsigned int dataoff,u8 protocol)64 __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
65 unsigned int dataoff, u8 protocol)
66 {
67 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
68 __sum16 csum = 0;
69
70 switch (skb->ip_summed) {
71 case CHECKSUM_COMPLETE:
72 if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
73 break;
74 if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
75 skb->len - dataoff, protocol,
76 csum_sub(skb->csum,
77 skb_checksum(skb, 0,
78 dataoff, 0)))) {
79 skb->ip_summed = CHECKSUM_UNNECESSARY;
80 break;
81 }
82 fallthrough;
83 case CHECKSUM_NONE:
84 skb->csum = ~csum_unfold(
85 csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
86 skb->len - dataoff,
87 protocol,
88 csum_sub(0,
89 skb_checksum(skb, 0,
90 dataoff, 0))));
91 csum = __skb_checksum_complete(skb);
92 }
93 return csum;
94 }
95 EXPORT_SYMBOL(nf_ip6_checksum);
96
nf_ip6_checksum_partial(struct sk_buff * skb,unsigned int hook,unsigned int dataoff,unsigned int len,u8 protocol)97 static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook,
98 unsigned int dataoff, unsigned int len,
99 u8 protocol)
100 {
101 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
102 __wsum hsum;
103 __sum16 csum = 0;
104
105 switch (skb->ip_summed) {
106 case CHECKSUM_COMPLETE:
107 if (len == skb->len - dataoff)
108 return nf_ip6_checksum(skb, hook, dataoff, protocol);
109 fallthrough;
110 case CHECKSUM_NONE:
111 hsum = skb_checksum(skb, 0, dataoff, 0);
112 skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr,
113 &ip6h->daddr,
114 skb->len - dataoff,
115 protocol,
116 csum_sub(0, hsum)));
117 skb->ip_summed = CHECKSUM_NONE;
118 return __skb_checksum_complete_head(skb, dataoff + len);
119 }
120 return csum;
121 };
122
nf_checksum(struct sk_buff * skb,unsigned int hook,unsigned int dataoff,u8 protocol,unsigned short family)123 __sum16 nf_checksum(struct sk_buff *skb, unsigned int hook,
124 unsigned int dataoff, u8 protocol,
125 unsigned short family)
126 {
127 __sum16 csum = 0;
128
129 switch (family) {
130 case AF_INET:
131 csum = nf_ip_checksum(skb, hook, dataoff, protocol);
132 break;
133 case AF_INET6:
134 csum = nf_ip6_checksum(skb, hook, dataoff, protocol);
135 break;
136 }
137
138 return csum;
139 }
140 EXPORT_SYMBOL_GPL(nf_checksum);
141
nf_checksum_partial(struct sk_buff * skb,unsigned int hook,unsigned int dataoff,unsigned int len,u8 protocol,unsigned short family)142 __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
143 unsigned int dataoff, unsigned int len,
144 u8 protocol, unsigned short family)
145 {
146 __sum16 csum = 0;
147
148 switch (family) {
149 case AF_INET:
150 csum = nf_ip_checksum_partial(skb, hook, dataoff, len,
151 protocol);
152 break;
153 case AF_INET6:
154 csum = nf_ip6_checksum_partial(skb, hook, dataoff, len,
155 protocol);
156 break;
157 }
158
159 return csum;
160 }
161 EXPORT_SYMBOL_GPL(nf_checksum_partial);
162
nf_route(struct net * net,struct dst_entry ** dst,struct flowi * fl,bool strict,unsigned short family)163 int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
164 bool strict, unsigned short family)
165 {
166 const struct nf_ipv6_ops *v6ops __maybe_unused;
167 int ret = 0;
168
169 switch (family) {
170 case AF_INET:
171 ret = nf_ip_route(net, dst, fl, strict);
172 break;
173 case AF_INET6:
174 ret = nf_ip6_route(net, dst, fl, strict);
175 break;
176 }
177
178 return ret;
179 }
180 EXPORT_SYMBOL_GPL(nf_route);
181
nf_ip_reroute(struct sk_buff * skb,const struct nf_queue_entry * entry)182 static int nf_ip_reroute(struct sk_buff *skb, const struct nf_queue_entry *entry)
183 {
184 #ifdef CONFIG_INET
185 const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
186
187 if (entry->state.hook == NF_INET_LOCAL_OUT) {
188 const struct iphdr *iph = ip_hdr(skb);
189
190 if (!(iph->tos == rt_info->tos &&
191 skb->mark == rt_info->mark &&
192 iph->daddr == rt_info->daddr &&
193 iph->saddr == rt_info->saddr))
194 return ip_route_me_harder(entry->state.net, entry->state.sk,
195 skb, RTN_UNSPEC);
196 }
197 #endif
198 return 0;
199 }
200
nf_reroute(struct sk_buff * skb,struct nf_queue_entry * entry)201 int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry)
202 {
203 const struct nf_ipv6_ops *v6ops;
204 int ret = 0;
205
206 switch (entry->state.pf) {
207 case AF_INET:
208 ret = nf_ip_reroute(skb, entry);
209 break;
210 case AF_INET6:
211 v6ops = rcu_dereference(nf_ipv6_ops);
212 if (v6ops)
213 ret = v6ops->reroute(skb, entry);
214 break;
215 }
216 return ret;
217 }
218
219 /* Only get and check the lengths, not do any hop-by-hop stuff. */
nf_ip6_check_hbh_len(struct sk_buff * skb,u32 * plen)220 int nf_ip6_check_hbh_len(struct sk_buff *skb, u32 *plen)
221 {
222 int len, off = sizeof(struct ipv6hdr);
223 unsigned char *nh;
224
225 if (!pskb_may_pull(skb, off + 8))
226 return -ENOMEM;
227 nh = (unsigned char *)(ipv6_hdr(skb) + 1);
228 len = (nh[1] + 1) << 3;
229
230 if (!pskb_may_pull(skb, off + len))
231 return -ENOMEM;
232 nh = skb_network_header(skb);
233
234 off += 2;
235 len -= 2;
236 while (len > 0) {
237 int optlen;
238
239 if (nh[off] == IPV6_TLV_PAD1) {
240 off++;
241 len--;
242 continue;
243 }
244 if (len < 2)
245 return -EBADMSG;
246 optlen = nh[off + 1] + 2;
247 if (optlen > len)
248 return -EBADMSG;
249
250 if (nh[off] == IPV6_TLV_JUMBO) {
251 u32 pkt_len;
252
253 if (nh[off + 1] != 4 || (off & 3) != 2)
254 return -EBADMSG;
255 pkt_len = ntohl(*(__be32 *)(nh + off + 2));
256 if (pkt_len <= IPV6_MAXPLEN ||
257 ipv6_hdr(skb)->payload_len)
258 return -EBADMSG;
259 if (pkt_len > skb->len - sizeof(struct ipv6hdr))
260 return -EBADMSG;
261 *plen = pkt_len;
262 }
263 off += optlen;
264 len -= optlen;
265 }
266
267 return len ? -EBADMSG : 0;
268 }
269 EXPORT_SYMBOL_GPL(nf_ip6_check_hbh_len);
270
