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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * mpls tunnels An implementation mpls tunnels using the light weight tunnel
4 * infrastructure
5 *
6 * Authors: Roopa Prabhu, <roopa@cumulusnetworks.com>
7 */
8#include <linux/types.h>
9#include <linux/skbuff.h>
10#include <linux/net.h>
11#include <linux/module.h>
12#include <linux/mpls.h>
13#include <linux/vmalloc.h>
14#include <net/ip.h>
15#include <net/dst.h>
16#include <net/lwtunnel.h>
17#include <net/netevent.h>
18#include <net/netns/generic.h>
19#include <net/ip6_fib.h>
20#include <net/route.h>
21#include <net/mpls_iptunnel.h>
22#include <linux/mpls_iptunnel.h>
23#include "internal.h"
24
25static const struct nla_policy mpls_iptunnel_policy[MPLS_IPTUNNEL_MAX + 1] = {
26 [MPLS_IPTUNNEL_DST] = { .len = sizeof(u32) },
27 [MPLS_IPTUNNEL_TTL] = { .type = NLA_U8 },
28};
29
30static unsigned int mpls_encap_size(struct mpls_iptunnel_encap *en)
31{
32 /* The size of the layer 2.5 labels to be added for this route */
33 return en->labels * sizeof(struct mpls_shim_hdr);
34}
35
36static int mpls_xmit(struct sk_buff *skb)
37{
38 struct mpls_iptunnel_encap *tun_encap_info;
39 struct mpls_shim_hdr *hdr;
40 struct net_device *out_dev;
41 unsigned int hh_len;
42 unsigned int new_header_size;
43 unsigned int mtu;
44 struct dst_entry *dst = skb_dst(skb);
45 struct rtable *rt = NULL;
46 struct rt6_info *rt6 = NULL;
47 struct mpls_dev *out_mdev;
48 struct net *net;
49 int err = 0;
50 bool bos;
51 int i;
52 unsigned int ttl;
53
54 /* Find the output device */
55 out_dev = dst->dev;
56 net = dev_net(out_dev);
57
58 skb_orphan(skb);
59
60 if (!mpls_output_possible(out_dev) ||
61 !dst->lwtstate || skb_warn_if_lro(skb))
62 goto drop;
63
64 skb_forward_csum(skb);
65
66 tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate);
67
68 /* Obtain the ttl using the following set of rules.
69 *
70 * LWT ttl propagation setting:
71 * - disabled => use default TTL value from LWT
72 * - enabled => use TTL value from IPv4/IPv6 header
73 * - default =>
74 * Global ttl propagation setting:
75 * - disabled => use default TTL value from global setting
76 * - enabled => use TTL value from IPv4/IPv6 header
77 */
78 if (dst->ops->family == AF_INET) {
79 if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
80 ttl = tun_encap_info->default_ttl;
81 else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
82 !net->mpls.ip_ttl_propagate)
83 ttl = net->mpls.default_ttl;
84 else
85 ttl = ip_hdr(skb)->ttl;
86 rt = (struct rtable *)dst;
87 } else if (dst->ops->family == AF_INET6) {
88 if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
89 ttl = tun_encap_info->default_ttl;
90 else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
91 !net->mpls.ip_ttl_propagate)
92 ttl = net->mpls.default_ttl;
93 else
94 ttl = ipv6_hdr(skb)->hop_limit;
95 rt6 = (struct rt6_info *)dst;
96 } else {
97 goto drop;
98 }
99
100 /* Verify the destination can hold the packet */
101 new_header_size = mpls_encap_size(tun_encap_info);
102 mtu = mpls_dev_mtu(out_dev);
103 if (mpls_pkt_too_big(skb, mtu - new_header_size))
104 goto drop;
105
106 hh_len = LL_RESERVED_SPACE(out_dev);
107 if (!out_dev->header_ops)
108 hh_len = 0;
109
110 /* Ensure there is enough space for the headers in the skb */
111 if (skb_cow(skb, hh_len + new_header_size))
112 goto drop;
113
114 skb_set_inner_protocol(skb, skb->protocol);
115 skb_reset_inner_network_header(skb);
116
117 skb_push(skb, new_header_size);
118
119 skb_reset_network_header(skb);
120
121 skb->dev = out_dev;
122 skb->protocol = htons(ETH_P_MPLS_UC);
123
124 /* Push the new labels */
125 hdr = mpls_hdr(skb);
126 bos = true;
127 for (i = tun_encap_info->labels - 1; i >= 0; i--) {
128 hdr[i] = mpls_entry_encode(tun_encap_info->label[i],
129 ttl, 0, bos);
130 bos = false;
131 }
132
133 mpls_stats_inc_outucastpkts(out_dev, skb);
134
135 if (rt) {
136 if (rt->rt_gw_family == AF_INET6)
137 err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt->rt_gw6,
138 skb);
139 else
140 err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gw4,
141 skb);
142 } else if (rt6) {
143 if (ipv6_addr_v4mapped(&rt6->rt6i_gateway)) {
144 /* 6PE (RFC 4798) */
145 err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt6->rt6i_gateway.s6_addr32[3],
146 skb);
147 } else
148 err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
149 skb);
150 }
151 if (err)
152 net_dbg_ratelimited("%s: packet transmission failed: %d\n",
153 __func__, err);
154
155 return LWTUNNEL_XMIT_DONE;
156
157drop:
158 out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;
159 if (out_mdev)
160 MPLS_INC_STATS(out_mdev, tx_errors);
161 kfree_skb(skb);
162 return -EINVAL;
163}
164
165static int mpls_build_state(struct net *net, struct nlattr *nla,
166 unsigned int family, const void *cfg,
167 struct lwtunnel_state **ts,
168 struct netlink_ext_ack *extack)
169{
170 struct mpls_iptunnel_encap *tun_encap_info;
171 struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1];
172 struct lwtunnel_state *newts;
173 u8 n_labels;
174 int ret;
175
176 ret = nla_parse_nested_deprecated(tb, MPLS_IPTUNNEL_MAX, nla,
177 mpls_iptunnel_policy, extack);
178 if (ret < 0)
179 return ret;
180
181 if (!tb[MPLS_IPTUNNEL_DST]) {
182 NL_SET_ERR_MSG(extack, "MPLS_IPTUNNEL_DST attribute is missing");
183 return -EINVAL;
184 }
185
186 /* determine number of labels */
187 if (nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS,
188 &n_labels, NULL, extack))
189 return -EINVAL;
190
191 newts = lwtunnel_state_alloc(struct_size(tun_encap_info, label,
192 n_labels));
193 if (!newts)
194 return -ENOMEM;
195
196 tun_encap_info = mpls_lwtunnel_encap(newts);
197 ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], n_labels,
198 &tun_encap_info->labels, tun_encap_info->label,
199 extack);
200 if (ret)
201 goto errout;
202
203 tun_encap_info->ttl_propagate = MPLS_TTL_PROP_DEFAULT;
204
205 if (tb[MPLS_IPTUNNEL_TTL]) {
206 tun_encap_info->default_ttl = nla_get_u8(tb[MPLS_IPTUNNEL_TTL]);
207 /* TTL 0 implies propagate from IP header */
208 tun_encap_info->ttl_propagate = tun_encap_info->default_ttl ?
209 MPLS_TTL_PROP_DISABLED :
210 MPLS_TTL_PROP_ENABLED;
211 }
212
213 newts->type = LWTUNNEL_ENCAP_MPLS;
214 newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
215 newts->headroom = mpls_encap_size(tun_encap_info);
216
217 *ts = newts;
218
219 return 0;
220
221errout:
222 kfree(newts);
223 *ts = NULL;
224
225 return ret;
226}
227
228static int mpls_fill_encap_info(struct sk_buff *skb,
229 struct lwtunnel_state *lwtstate)
230{
231 struct mpls_iptunnel_encap *tun_encap_info;
232
233 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
234
235 if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels,
236 tun_encap_info->label))
237 goto nla_put_failure;
238
239 if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT &&
240 nla_put_u8(skb, MPLS_IPTUNNEL_TTL, tun_encap_info->default_ttl))
241 goto nla_put_failure;
242
243 return 0;
244
245nla_put_failure:
246 return -EMSGSIZE;
247}
248
249static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate)
250{
251 struct mpls_iptunnel_encap *tun_encap_info;
252 int nlsize;
253
254 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
255
256 nlsize = nla_total_size(tun_encap_info->labels * 4);
257
258 if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT)
259 nlsize += nla_total_size(1);
260
261 return nlsize;
262}
263
264static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
265{
266 struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a);
267 struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b);
268 int l;
269
270 if (a_hdr->labels != b_hdr->labels ||
271 a_hdr->ttl_propagate != b_hdr->ttl_propagate ||
272 a_hdr->default_ttl != b_hdr->default_ttl)
273 return 1;
274
275 for (l = 0; l < a_hdr->labels; l++)
276 if (a_hdr->label[l] != b_hdr->label[l])
277 return 1;
278 return 0;
279}
280
281static const struct lwtunnel_encap_ops mpls_iptun_ops = {
282 .build_state = mpls_build_state,
283 .xmit = mpls_xmit,
284 .fill_encap = mpls_fill_encap_info,
285 .get_encap_size = mpls_encap_nlsize,
286 .cmp_encap = mpls_encap_cmp,
287 .owner = THIS_MODULE,
288};
289
290static int __init mpls_iptunnel_init(void)
291{
292 return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
293}
294module_init(mpls_iptunnel_init);
295
296static void __exit mpls_iptunnel_exit(void)
297{
298 lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
299}
300module_exit(mpls_iptunnel_exit);
301
302MODULE_ALIAS_RTNL_LWT(MPLS);
303MODULE_SOFTDEP("post: mpls_gso");
304MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels");
305MODULE_LICENSE("GPL v2");
1/*
2 * mpls tunnels An implementation mpls tunnels using the light weight tunnel
3 * infrastructure
4 *
5 * Authors: Roopa Prabhu, <roopa@cumulusnetworks.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 */
13#include <linux/types.h>
14#include <linux/skbuff.h>
15#include <linux/net.h>
16#include <linux/module.h>
17#include <linux/mpls.h>
18#include <linux/vmalloc.h>
19#include <net/ip.h>
20#include <net/dst.h>
21#include <net/lwtunnel.h>
22#include <net/netevent.h>
23#include <net/netns/generic.h>
24#include <net/ip6_fib.h>
25#include <net/route.h>
26#include <net/mpls_iptunnel.h>
27#include <linux/mpls_iptunnel.h>
28#include "internal.h"
29
30static const struct nla_policy mpls_iptunnel_policy[MPLS_IPTUNNEL_MAX + 1] = {
31 [MPLS_IPTUNNEL_DST] = { .type = NLA_U32 },
32};
33
34static unsigned int mpls_encap_size(struct mpls_iptunnel_encap *en)
35{
36 /* The size of the layer 2.5 labels to be added for this route */
37 return en->labels * sizeof(struct mpls_shim_hdr);
38}
39
40static int mpls_output(struct net *net, struct sock *sk, struct sk_buff *skb)
41{
42 struct mpls_iptunnel_encap *tun_encap_info;
43 struct mpls_shim_hdr *hdr;
44 struct net_device *out_dev;
45 unsigned int hh_len;
46 unsigned int new_header_size;
47 unsigned int mtu;
48 struct dst_entry *dst = skb_dst(skb);
49 struct rtable *rt = NULL;
50 struct rt6_info *rt6 = NULL;
51 int err = 0;
52 bool bos;
53 int i;
54 unsigned int ttl;
55
56 /* Obtain the ttl */
57 if (dst->ops->family == AF_INET) {
58 ttl = ip_hdr(skb)->ttl;
59 rt = (struct rtable *)dst;
60 } else if (dst->ops->family == AF_INET6) {
61 ttl = ipv6_hdr(skb)->hop_limit;
62 rt6 = (struct rt6_info *)dst;
63 } else {
64 goto drop;
65 }
66
67 skb_orphan(skb);
68
69 /* Find the output device */
70 out_dev = dst->dev;
71 if (!mpls_output_possible(out_dev) ||
72 !dst->lwtstate || skb_warn_if_lro(skb))
73 goto drop;
74
75 skb_forward_csum(skb);
76
77 tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate);
78
79 /* Verify the destination can hold the packet */
80 new_header_size = mpls_encap_size(tun_encap_info);
81 mtu = mpls_dev_mtu(out_dev);
82 if (mpls_pkt_too_big(skb, mtu - new_header_size))
83 goto drop;
84
85 hh_len = LL_RESERVED_SPACE(out_dev);
86 if (!out_dev->header_ops)
87 hh_len = 0;
88
89 /* Ensure there is enough space for the headers in the skb */
90 if (skb_cow(skb, hh_len + new_header_size))
91 goto drop;
92
93 skb_push(skb, new_header_size);
94 skb_reset_network_header(skb);
95
96 skb->dev = out_dev;
97 skb->protocol = htons(ETH_P_MPLS_UC);
98
99 /* Push the new labels */
100 hdr = mpls_hdr(skb);
101 bos = true;
102 for (i = tun_encap_info->labels - 1; i >= 0; i--) {
103 hdr[i] = mpls_entry_encode(tun_encap_info->label[i],
104 ttl, 0, bos);
105 bos = false;
106 }
107
108 if (rt)
109 err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway,
110 skb);
111 else if (rt6)
112 err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
113 skb);
114 if (err)
115 net_dbg_ratelimited("%s: packet transmission failed: %d\n",
116 __func__, err);
117
118 return 0;
119
120drop:
121 kfree_skb(skb);
122 return -EINVAL;
123}
124
125static int mpls_build_state(struct net_device *dev, struct nlattr *nla,
126 unsigned int family, const void *cfg,
127 struct lwtunnel_state **ts)
128{
129 struct mpls_iptunnel_encap *tun_encap_info;
130 struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1];
131 struct lwtunnel_state *newts;
132 int tun_encap_info_len;
133 int ret;
134
135 ret = nla_parse_nested(tb, MPLS_IPTUNNEL_MAX, nla,
136 mpls_iptunnel_policy);
137 if (ret < 0)
138 return ret;
139
140 if (!tb[MPLS_IPTUNNEL_DST])
141 return -EINVAL;
142
143 tun_encap_info_len = sizeof(*tun_encap_info);
144
145 newts = lwtunnel_state_alloc(tun_encap_info_len);
146 if (!newts)
147 return -ENOMEM;
148
149 newts->len = tun_encap_info_len;
150 tun_encap_info = mpls_lwtunnel_encap(newts);
151 ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS,
152 &tun_encap_info->labels, tun_encap_info->label);
153 if (ret)
154 goto errout;
155 newts->type = LWTUNNEL_ENCAP_MPLS;
156 newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
157
158 *ts = newts;
159
160 return 0;
161
162errout:
163 kfree(newts);
164 *ts = NULL;
165
166 return ret;
167}
168
169static int mpls_fill_encap_info(struct sk_buff *skb,
170 struct lwtunnel_state *lwtstate)
171{
172 struct mpls_iptunnel_encap *tun_encap_info;
173
174 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
175
176 if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels,
177 tun_encap_info->label))
178 goto nla_put_failure;
179
180 return 0;
181
182nla_put_failure:
183 return -EMSGSIZE;
184}
185
186static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate)
187{
188 struct mpls_iptunnel_encap *tun_encap_info;
189
190 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
191
192 return nla_total_size(tun_encap_info->labels * 4);
193}
194
195static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
196{
197 struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a);
198 struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b);
199 int l;
200
201 if (a_hdr->labels != b_hdr->labels)
202 return 1;
203
204 for (l = 0; l < MAX_NEW_LABELS; l++)
205 if (a_hdr->label[l] != b_hdr->label[l])
206 return 1;
207 return 0;
208}
209
210static const struct lwtunnel_encap_ops mpls_iptun_ops = {
211 .build_state = mpls_build_state,
212 .output = mpls_output,
213 .fill_encap = mpls_fill_encap_info,
214 .get_encap_size = mpls_encap_nlsize,
215 .cmp_encap = mpls_encap_cmp,
216};
217
218static int __init mpls_iptunnel_init(void)
219{
220 return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
221}
222module_init(mpls_iptunnel_init);
223
224static void __exit mpls_iptunnel_exit(void)
225{
226 lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
227}
228module_exit(mpls_iptunnel_exit);
229
230MODULE_ALIAS_RTNL_LWT(MPLS);
231MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels");
232MODULE_LICENSE("GPL v2");