1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * IPv6 IOAM Lightweight Tunnel implementation
4 *
5 * Author:
6 * Justin Iurman <justin.iurman@uliege.be>
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/skbuff.h>
11 #include <linux/net.h>
12 #include <linux/netlink.h>
13 #include <linux/in6.h>
14 #include <linux/ioam6.h>
15 #include <linux/ioam6_iptunnel.h>
16 #include <net/dst.h>
17 #include <net/sock.h>
18 #include <net/lwtunnel.h>
19 #include <net/ioam6.h>
20
21 #define IOAM6_MASK_SHORT_FIELDS 0xff100000
22 #define IOAM6_MASK_WIDE_FIELDS 0xe00000
23
24 struct ioam6_lwt_encap {
25 struct ipv6_hopopt_hdr eh;
26 u8 pad[2]; /* 2-octet padding for 4n-alignment */
27 struct ioam6_hdr ioamh;
28 struct ioam6_trace_hdr traceh;
29 } __packed;
30
31 struct ioam6_lwt {
32 struct ioam6_lwt_encap tuninfo;
33 };
34
ioam6_lwt_state(struct lwtunnel_state * lwt)35 static struct ioam6_lwt *ioam6_lwt_state(struct lwtunnel_state *lwt)
36 {
37 return (struct ioam6_lwt *)lwt->data;
38 }
39
ioam6_lwt_info(struct lwtunnel_state * lwt)40 static struct ioam6_lwt_encap *ioam6_lwt_info(struct lwtunnel_state *lwt)
41 {
42 return &ioam6_lwt_state(lwt)->tuninfo;
43 }
44
ioam6_trace(struct lwtunnel_state * lwt)45 static struct ioam6_trace_hdr *ioam6_trace(struct lwtunnel_state *lwt)
46 {
47 return &(ioam6_lwt_state(lwt)->tuninfo.traceh);
48 }
49
50 static const struct nla_policy ioam6_iptunnel_policy[IOAM6_IPTUNNEL_MAX + 1] = {
51 [IOAM6_IPTUNNEL_TRACE] = NLA_POLICY_EXACT_LEN(sizeof(struct ioam6_trace_hdr)),
52 };
53
nla_put_ioam6_trace(struct sk_buff * skb,int attrtype,struct ioam6_trace_hdr * trace)54 static int nla_put_ioam6_trace(struct sk_buff *skb, int attrtype,
55 struct ioam6_trace_hdr *trace)
56 {
57 struct ioam6_trace_hdr *data;
58 struct nlattr *nla;
59 int len;
60
61 len = sizeof(*trace);
62
63 nla = nla_reserve(skb, attrtype, len);
64 if (!nla)
65 return -EMSGSIZE;
66
67 data = nla_data(nla);
68 memcpy(data, trace, len);
69
70 return 0;
71 }
72
ioam6_validate_trace_hdr(struct ioam6_trace_hdr * trace)73 static bool ioam6_validate_trace_hdr(struct ioam6_trace_hdr *trace)
74 {
75 u32 fields;
76
77 if (!trace->type_be32 || !trace->remlen ||
78 trace->remlen > IOAM6_TRACE_DATA_SIZE_MAX / 4 ||
79 trace->type.bit12 | trace->type.bit13 | trace->type.bit14 |
80 trace->type.bit15 | trace->type.bit16 | trace->type.bit17 |
81 trace->type.bit18 | trace->type.bit19 | trace->type.bit20 |
82 trace->type.bit21)
83 return false;
84
85 trace->nodelen = 0;
86 fields = be32_to_cpu(trace->type_be32);
87
88 trace->nodelen += hweight32(fields & IOAM6_MASK_SHORT_FIELDS)
89 * (sizeof(__be32) / 4);
90 trace->nodelen += hweight32(fields & IOAM6_MASK_WIDE_FIELDS)
91 * (sizeof(__be64) / 4);
92
93 return true;
94 }
95
ioam6_build_state(struct net * net,struct nlattr * nla,unsigned int family,const void * cfg,struct lwtunnel_state ** ts,struct netlink_ext_ack * extack)96 static int ioam6_build_state(struct net *net, struct nlattr *nla,
97 unsigned int family, const void *cfg,
98 struct lwtunnel_state **ts,
99 struct netlink_ext_ack *extack)
100 {
101 struct nlattr *tb[IOAM6_IPTUNNEL_MAX + 1];
102 struct ioam6_lwt_encap *tuninfo;
103 struct ioam6_trace_hdr *trace;
104 struct lwtunnel_state *s;
105 int len_aligned;
106 int len, err;
107
108 if (family != AF_INET6)
109 return -EINVAL;
110
111 err = nla_parse_nested(tb, IOAM6_IPTUNNEL_MAX, nla,
112 ioam6_iptunnel_policy, extack);
113 if (err < 0)
114 return err;
115
116 if (!tb[IOAM6_IPTUNNEL_TRACE]) {
117 NL_SET_ERR_MSG(extack, "missing trace");
118 return -EINVAL;
119 }
120
121 trace = nla_data(tb[IOAM6_IPTUNNEL_TRACE]);
122 if (!ioam6_validate_trace_hdr(trace)) {
123 NL_SET_ERR_MSG_ATTR(extack, tb[IOAM6_IPTUNNEL_TRACE],
124 "invalid trace validation");
125 return -EINVAL;
126 }
127
128 len = sizeof(*tuninfo) + trace->remlen * 4;
129 len_aligned = ALIGN(len, 8);
130
131 s = lwtunnel_state_alloc(len_aligned);
132 if (!s)
133 return -ENOMEM;
134
135 tuninfo = ioam6_lwt_info(s);
136 tuninfo->eh.hdrlen = (len_aligned >> 3) - 1;
137 tuninfo->pad[0] = IPV6_TLV_PADN;
138 tuninfo->ioamh.type = IOAM6_TYPE_PREALLOC;
139 tuninfo->ioamh.opt_type = IPV6_TLV_IOAM;
140 tuninfo->ioamh.opt_len = sizeof(tuninfo->ioamh) - 2 + sizeof(*trace)
141 + trace->remlen * 4;
142
143 memcpy(&tuninfo->traceh, trace, sizeof(*trace));
144
145 len = len_aligned - len;
146 if (len == 1) {
147 tuninfo->traceh.data[trace->remlen * 4] = IPV6_TLV_PAD1;
148 } else if (len > 0) {
149 tuninfo->traceh.data[trace->remlen * 4] = IPV6_TLV_PADN;
150 tuninfo->traceh.data[trace->remlen * 4 + 1] = len - 2;
151 }
152
153 s->type = LWTUNNEL_ENCAP_IOAM6;
154 s->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
155
156 *ts = s;
157
158 return 0;
159 }
160
ioam6_do_inline(struct sk_buff * skb,struct ioam6_lwt_encap * tuninfo)161 static int ioam6_do_inline(struct sk_buff *skb, struct ioam6_lwt_encap *tuninfo)
162 {
163 struct ioam6_trace_hdr *trace;
164 struct ipv6hdr *oldhdr, *hdr;
165 struct ioam6_namespace *ns;
166 int hdrlen, err;
167
168 hdrlen = (tuninfo->eh.hdrlen + 1) << 3;
169
170 err = skb_cow_head(skb, hdrlen + skb->mac_len);
171 if (unlikely(err))
172 return err;
173
174 oldhdr = ipv6_hdr(skb);
175 skb_pull(skb, sizeof(*oldhdr));
176 skb_postpull_rcsum(skb, skb_network_header(skb), sizeof(*oldhdr));
177
178 skb_push(skb, sizeof(*oldhdr) + hdrlen);
179 skb_reset_network_header(skb);
180 skb_mac_header_rebuild(skb);
181
182 hdr = ipv6_hdr(skb);
183 memmove(hdr, oldhdr, sizeof(*oldhdr));
184 tuninfo->eh.nexthdr = hdr->nexthdr;
185
186 skb_set_transport_header(skb, sizeof(*hdr));
187 skb_postpush_rcsum(skb, hdr, sizeof(*hdr) + hdrlen);
188
189 memcpy(skb_transport_header(skb), (u8 *)tuninfo, hdrlen);
190
191 hdr->nexthdr = NEXTHDR_HOP;
192 hdr->payload_len = cpu_to_be16(skb->len - sizeof(*hdr));
193
194 trace = (struct ioam6_trace_hdr *)(skb_transport_header(skb)
195 + sizeof(struct ipv6_hopopt_hdr) + 2
196 + sizeof(struct ioam6_hdr));
197
198 ns = ioam6_namespace(dev_net(skb_dst(skb)->dev), trace->namespace_id);
199 if (ns)
200 ioam6_fill_trace_data(skb, ns, trace);
201
202 return 0;
203 }
204
ioam6_output(struct net * net,struct sock * sk,struct sk_buff * skb)205 static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
206 {
207 struct lwtunnel_state *lwt = skb_dst(skb)->lwtstate;
208 int err = -EINVAL;
209
210 if (skb->protocol != htons(ETH_P_IPV6))
211 goto drop;
212
213 /* Only for packets we send and
214 * that do not contain a Hop-by-Hop yet
215 */
216 if (skb->dev || ipv6_hdr(skb)->nexthdr == NEXTHDR_HOP)
217 goto out;
218
219 err = ioam6_do_inline(skb, ioam6_lwt_info(lwt));
220 if (unlikely(err))
221 goto drop;
222
223 err = skb_cow_head(skb, LL_RESERVED_SPACE(skb_dst(skb)->dev));
224 if (unlikely(err))
225 goto drop;
226
227 out:
228 return lwt->orig_output(net, sk, skb);
229
230 drop:
231 kfree_skb(skb);
232 return err;
233 }
234
ioam6_fill_encap_info(struct sk_buff * skb,struct lwtunnel_state * lwtstate)235 static int ioam6_fill_encap_info(struct sk_buff *skb,
236 struct lwtunnel_state *lwtstate)
237 {
238 struct ioam6_trace_hdr *trace = ioam6_trace(lwtstate);
239
240 if (nla_put_ioam6_trace(skb, IOAM6_IPTUNNEL_TRACE, trace))
241 return -EMSGSIZE;
242
243 return 0;
244 }
245
ioam6_encap_nlsize(struct lwtunnel_state * lwtstate)246 static int ioam6_encap_nlsize(struct lwtunnel_state *lwtstate)
247 {
248 struct ioam6_trace_hdr *trace = ioam6_trace(lwtstate);
249
250 return nla_total_size(sizeof(*trace));
251 }
252
ioam6_encap_cmp(struct lwtunnel_state * a,struct lwtunnel_state * b)253 static int ioam6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
254 {
255 struct ioam6_trace_hdr *a_hdr = ioam6_trace(a);
256 struct ioam6_trace_hdr *b_hdr = ioam6_trace(b);
257
258 return (a_hdr->namespace_id != b_hdr->namespace_id);
259 }
260
261 static const struct lwtunnel_encap_ops ioam6_iptun_ops = {
262 .build_state = ioam6_build_state,
263 .output = ioam6_output,
264 .fill_encap = ioam6_fill_encap_info,
265 .get_encap_size = ioam6_encap_nlsize,
266 .cmp_encap = ioam6_encap_cmp,
267 .owner = THIS_MODULE,
268 };
269
ioam6_iptunnel_init(void)270 int __init ioam6_iptunnel_init(void)
271 {
272 return lwtunnel_encap_add_ops(&ioam6_iptun_ops, LWTUNNEL_ENCAP_IOAM6);
273 }
274
ioam6_iptunnel_exit(void)275 void ioam6_iptunnel_exit(void)
276 {
277 lwtunnel_encap_del_ops(&ioam6_iptun_ops, LWTUNNEL_ENCAP_IOAM6);
278 }
279
