1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | #include <linux/module.h> |
3 | #include <linux/errno.h> |
4 | #include <linux/socket.h> |
5 | #include <linux/skbuff.h> |
6 | #include <linux/ip.h> |
7 | #include <linux/udp.h> |
8 | #include <linux/icmpv6.h> |
9 | #include <linux/types.h> |
10 | #include <linux/kernel.h> |
11 | #include <net/fou.h> |
12 | #include <net/ip.h> |
13 | #include <net/ip6_tunnel.h> |
14 | #include <net/ip6_checksum.h> |
15 | #include <net/protocol.h> |
16 | #include <net/udp.h> |
17 | #include <net/udp_tunnel.h> |
18 | |
19 | #if IS_ENABLED(CONFIG_IPV6_FOU_TUNNEL) |
20 | |
21 | static void fou6_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e, |
22 | struct flowi6 *fl6, u8 *protocol, __be16 sport) |
23 | { |
24 | struct udphdr *uh; |
25 | |
26 | skb_push(skb, len: sizeof(struct udphdr)); |
27 | skb_reset_transport_header(skb); |
28 | |
29 | uh = udp_hdr(skb); |
30 | |
31 | uh->dest = e->dport; |
32 | uh->source = sport; |
33 | uh->len = htons(skb->len); |
34 | udp6_set_csum(nocheck: !(e->flags & TUNNEL_ENCAP_FLAG_CSUM6), skb, |
35 | saddr: &fl6->saddr, daddr: &fl6->daddr, len: skb->len); |
36 | |
37 | *protocol = IPPROTO_UDP; |
38 | } |
39 | |
40 | static int (struct sk_buff *skb, struct ip_tunnel_encap *e, |
41 | u8 *protocol, struct flowi6 *fl6) |
42 | { |
43 | __be16 sport; |
44 | int err; |
45 | int type = e->flags & TUNNEL_ENCAP_FLAG_CSUM6 ? |
46 | SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL; |
47 | |
48 | err = __fou_build_header(skb, e, protocol, sport: &sport, type); |
49 | if (err) |
50 | return err; |
51 | |
52 | fou6_build_udp(skb, e, fl6, protocol, sport); |
53 | |
54 | return 0; |
55 | } |
56 | |
57 | static int (struct sk_buff *skb, struct ip_tunnel_encap *e, |
58 | u8 *protocol, struct flowi6 *fl6) |
59 | { |
60 | __be16 sport; |
61 | int err; |
62 | int type = e->flags & TUNNEL_ENCAP_FLAG_CSUM6 ? |
63 | SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL; |
64 | |
65 | err = __gue_build_header(skb, e, protocol, sport: &sport, type); |
66 | if (err) |
67 | return err; |
68 | |
69 | fou6_build_udp(skb, e, fl6, protocol, sport); |
70 | |
71 | return 0; |
72 | } |
73 | |
74 | static int gue6_err_proto_handler(int proto, struct sk_buff *skb, |
75 | struct inet6_skb_parm *opt, |
76 | u8 type, u8 code, int offset, __be32 info) |
77 | { |
78 | const struct inet6_protocol *ipprot; |
79 | |
80 | ipprot = rcu_dereference(inet6_protos[proto]); |
81 | if (ipprot && ipprot->err_handler) { |
82 | if (!ipprot->err_handler(skb, opt, type, code, offset, info)) |
83 | return 0; |
84 | } |
85 | |
86 | return -ENOENT; |
87 | } |
88 | |
89 | static int gue6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, |
90 | u8 type, u8 code, int offset, __be32 info) |
91 | { |
92 | int transport_offset = skb_transport_offset(skb); |
93 | struct guehdr *guehdr; |
94 | size_t len, optlen; |
95 | int ret; |
96 | |
97 | len = sizeof(struct udphdr) + sizeof(struct guehdr); |
98 | if (!pskb_may_pull(skb, len: transport_offset + len)) |
99 | return -EINVAL; |
100 | |
101 | guehdr = (struct guehdr *)&udp_hdr(skb)[1]; |
102 | |
103 | switch (guehdr->version) { |
104 | case 0: /* Full GUE header present */ |
105 | break; |
106 | case 1: { |
107 | /* Direct encasulation of IPv4 or IPv6 */ |
108 | skb_set_transport_header(skb, offset: -(int)sizeof(struct icmp6hdr)); |
109 | |
110 | switch (((struct iphdr *)guehdr)->version) { |
111 | case 4: |
112 | ret = gue6_err_proto_handler(IPPROTO_IPIP, skb, opt, |
113 | type, code, offset, info); |
114 | goto out; |
115 | case 6: |
116 | ret = gue6_err_proto_handler(IPPROTO_IPV6, skb, opt, |
117 | type, code, offset, info); |
118 | goto out; |
119 | default: |
120 | ret = -EOPNOTSUPP; |
121 | goto out; |
122 | } |
123 | } |
124 | default: /* Undefined version */ |
125 | return -EOPNOTSUPP; |
126 | } |
127 | |
128 | if (guehdr->control) |
129 | return -ENOENT; |
130 | |
131 | optlen = guehdr->hlen << 2; |
132 | |
133 | if (!pskb_may_pull(skb, len: transport_offset + len + optlen)) |
134 | return -EINVAL; |
135 | |
136 | guehdr = (struct guehdr *)&udp_hdr(skb)[1]; |
137 | if (validate_gue_flags(guehdr, optlen)) |
138 | return -EINVAL; |
139 | |
140 | /* Handling exceptions for direct UDP encapsulation in GUE would lead to |
141 | * recursion. Besides, this kind of encapsulation can't even be |
142 | * configured currently. Discard this. |
143 | */ |
144 | if (guehdr->proto_ctype == IPPROTO_UDP || |
145 | guehdr->proto_ctype == IPPROTO_UDPLITE) |
146 | return -EOPNOTSUPP; |
147 | |
148 | skb_set_transport_header(skb, offset: -(int)sizeof(struct icmp6hdr)); |
149 | ret = gue6_err_proto_handler(proto: guehdr->proto_ctype, skb, |
150 | opt, type, code, offset, info); |
151 | |
152 | out: |
153 | skb_set_transport_header(skb, offset: transport_offset); |
154 | return ret; |
155 | } |
156 | |
157 | |
158 | static const struct ip6_tnl_encap_ops fou_ip6tun_ops = { |
159 | .encap_hlen = fou_encap_hlen, |
160 | .build_header = fou6_build_header, |
161 | .err_handler = gue6_err, |
162 | }; |
163 | |
164 | static const struct ip6_tnl_encap_ops gue_ip6tun_ops = { |
165 | .encap_hlen = gue_encap_hlen, |
166 | .build_header = gue6_build_header, |
167 | .err_handler = gue6_err, |
168 | }; |
169 | |
170 | static int ip6_tnl_encap_add_fou_ops(void) |
171 | { |
172 | int ret; |
173 | |
174 | ret = ip6_tnl_encap_add_ops(ops: &fou_ip6tun_ops, num: TUNNEL_ENCAP_FOU); |
175 | if (ret < 0) { |
176 | pr_err("can't add fou6 ops\n" ); |
177 | return ret; |
178 | } |
179 | |
180 | ret = ip6_tnl_encap_add_ops(ops: &gue_ip6tun_ops, num: TUNNEL_ENCAP_GUE); |
181 | if (ret < 0) { |
182 | pr_err("can't add gue6 ops\n" ); |
183 | ip6_tnl_encap_del_ops(ops: &fou_ip6tun_ops, num: TUNNEL_ENCAP_FOU); |
184 | return ret; |
185 | } |
186 | |
187 | return 0; |
188 | } |
189 | |
190 | static void ip6_tnl_encap_del_fou_ops(void) |
191 | { |
192 | ip6_tnl_encap_del_ops(ops: &fou_ip6tun_ops, num: TUNNEL_ENCAP_FOU); |
193 | ip6_tnl_encap_del_ops(ops: &gue_ip6tun_ops, num: TUNNEL_ENCAP_GUE); |
194 | } |
195 | |
196 | #else |
197 | |
198 | static int ip6_tnl_encap_add_fou_ops(void) |
199 | { |
200 | return 0; |
201 | } |
202 | |
203 | static void ip6_tnl_encap_del_fou_ops(void) |
204 | { |
205 | } |
206 | |
207 | #endif |
208 | |
209 | static int __init fou6_init(void) |
210 | { |
211 | int ret; |
212 | |
213 | ret = ip6_tnl_encap_add_fou_ops(); |
214 | |
215 | return ret; |
216 | } |
217 | |
218 | static void __exit fou6_fini(void) |
219 | { |
220 | ip6_tnl_encap_del_fou_ops(); |
221 | } |
222 | |
223 | module_init(fou6_init); |
224 | module_exit(fou6_fini); |
225 | MODULE_AUTHOR("Tom Herbert <therbert@google.com>" ); |
226 | MODULE_LICENSE("GPL" ); |
227 | MODULE_DESCRIPTION("Foo over UDP (IPv6)" ); |
228 | |