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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 if (!mpls_output_possible(out_dev) ||
59 !dst->lwtstate || skb_warn_if_lro(skb))
60 goto drop;
61
62 skb_forward_csum(skb);
63
64 tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate);
65
66 /* Obtain the ttl using the following set of rules.
67 *
68 * LWT ttl propagation setting:
69 * - disabled => use default TTL value from LWT
70 * - enabled => use TTL value from IPv4/IPv6 header
71 * - default =>
72 * Global ttl propagation setting:
73 * - disabled => use default TTL value from global setting
74 * - enabled => use TTL value from IPv4/IPv6 header
75 */
76 if (dst->ops->family == AF_INET) {
77 if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
78 ttl = tun_encap_info->default_ttl;
79 else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
80 !net->mpls.ip_ttl_propagate)
81 ttl = net->mpls.default_ttl;
82 else
83 ttl = ip_hdr(skb)->ttl;
84 rt = dst_rtable(dst);
85 } else if (dst->ops->family == AF_INET6) {
86 if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
87 ttl = tun_encap_info->default_ttl;
88 else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
89 !net->mpls.ip_ttl_propagate)
90 ttl = net->mpls.default_ttl;
91 else
92 ttl = ipv6_hdr(skb)->hop_limit;
93 rt6 = dst_rt6_info(dst);
94 } else {
95 goto drop;
96 }
97
98 /* Verify the destination can hold the packet */
99 new_header_size = mpls_encap_size(tun_encap_info);
100 mtu = mpls_dev_mtu(out_dev);
101 if (mpls_pkt_too_big(skb, mtu - new_header_size))
102 goto drop;
103
104 hh_len = LL_RESERVED_SPACE(out_dev);
105 if (!out_dev->header_ops)
106 hh_len = 0;
107
108 /* Ensure there is enough space for the headers in the skb */
109 if (skb_cow_head(skb, hh_len + new_header_size))
110 goto drop;
111
112 skb_set_inner_protocol(skb, skb->protocol);
113 skb_reset_inner_network_header(skb);
114
115 skb_push(skb, new_header_size);
116
117 skb_reset_network_header(skb);
118
119 skb->dev = out_dev;
120 skb->protocol = htons(ETH_P_MPLS_UC);
121
122 /* Push the new labels */
123 hdr = mpls_hdr(skb);
124 bos = true;
125 for (i = tun_encap_info->labels - 1; i >= 0; i--) {
126 hdr[i] = mpls_entry_encode(tun_encap_info->label[i],
127 ttl, 0, bos);
128 bos = false;
129 }
130
131 mpls_stats_inc_outucastpkts(out_dev, skb);
132
133 if (rt) {
134 if (rt->rt_gw_family == AF_INET6)
135 err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt->rt_gw6,
136 skb);
137 else
138 err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gw4,
139 skb);
140 } else if (rt6) {
141 if (ipv6_addr_v4mapped(&rt6->rt6i_gateway)) {
142 /* 6PE (RFC 4798) */
143 err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt6->rt6i_gateway.s6_addr32[3],
144 skb);
145 } else
146 err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
147 skb);
148 }
149 if (err)
150 net_dbg_ratelimited("%s: packet transmission failed: %d\n",
151 __func__, err);
152
153 return LWTUNNEL_XMIT_DONE;
154
155drop:
156 out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;
157 if (out_mdev)
158 MPLS_INC_STATS(out_mdev, tx_errors);
159 kfree_skb(skb);
160 return -EINVAL;
161}
162
163static int mpls_build_state(struct net *net, struct nlattr *nla,
164 unsigned int family, const void *cfg,
165 struct lwtunnel_state **ts,
166 struct netlink_ext_ack *extack)
167{
168 struct mpls_iptunnel_encap *tun_encap_info;
169 struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1];
170 struct lwtunnel_state *newts;
171 u8 n_labels;
172 int ret;
173
174 ret = nla_parse_nested_deprecated(tb, MPLS_IPTUNNEL_MAX, nla,
175 mpls_iptunnel_policy, extack);
176 if (ret < 0)
177 return ret;
178
179 if (!tb[MPLS_IPTUNNEL_DST]) {
180 NL_SET_ERR_MSG(extack, "MPLS_IPTUNNEL_DST attribute is missing");
181 return -EINVAL;
182 }
183
184 /* determine number of labels */
185 if (nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS,
186 &n_labels, NULL, extack))
187 return -EINVAL;
188
189 newts = lwtunnel_state_alloc(struct_size(tun_encap_info, label,
190 n_labels));
191 if (!newts)
192 return -ENOMEM;
193
194 tun_encap_info = mpls_lwtunnel_encap(newts);
195 ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], n_labels,
196 &tun_encap_info->labels, tun_encap_info->label,
197 extack);
198 if (ret)
199 goto errout;
200
201 tun_encap_info->ttl_propagate = MPLS_TTL_PROP_DEFAULT;
202
203 if (tb[MPLS_IPTUNNEL_TTL]) {
204 tun_encap_info->default_ttl = nla_get_u8(tb[MPLS_IPTUNNEL_TTL]);
205 /* TTL 0 implies propagate from IP header */
206 tun_encap_info->ttl_propagate = tun_encap_info->default_ttl ?
207 MPLS_TTL_PROP_DISABLED :
208 MPLS_TTL_PROP_ENABLED;
209 }
210
211 newts->type = LWTUNNEL_ENCAP_MPLS;
212 newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
213 newts->headroom = mpls_encap_size(tun_encap_info);
214
215 *ts = newts;
216
217 return 0;
218
219errout:
220 kfree(newts);
221 *ts = NULL;
222
223 return ret;
224}
225
226static int mpls_fill_encap_info(struct sk_buff *skb,
227 struct lwtunnel_state *lwtstate)
228{
229 struct mpls_iptunnel_encap *tun_encap_info;
230
231 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
232
233 if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels,
234 tun_encap_info->label))
235 goto nla_put_failure;
236
237 if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT &&
238 nla_put_u8(skb, MPLS_IPTUNNEL_TTL, tun_encap_info->default_ttl))
239 goto nla_put_failure;
240
241 return 0;
242
243nla_put_failure:
244 return -EMSGSIZE;
245}
246
247static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate)
248{
249 struct mpls_iptunnel_encap *tun_encap_info;
250 int nlsize;
251
252 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
253
254 nlsize = nla_total_size(tun_encap_info->labels * 4);
255
256 if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT)
257 nlsize += nla_total_size(1);
258
259 return nlsize;
260}
261
262static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
263{
264 struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a);
265 struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b);
266 int l;
267
268 if (a_hdr->labels != b_hdr->labels ||
269 a_hdr->ttl_propagate != b_hdr->ttl_propagate ||
270 a_hdr->default_ttl != b_hdr->default_ttl)
271 return 1;
272
273 for (l = 0; l < a_hdr->labels; l++)
274 if (a_hdr->label[l] != b_hdr->label[l])
275 return 1;
276 return 0;
277}
278
279static const struct lwtunnel_encap_ops mpls_iptun_ops = {
280 .build_state = mpls_build_state,
281 .xmit = mpls_xmit,
282 .fill_encap = mpls_fill_encap_info,
283 .get_encap_size = mpls_encap_nlsize,
284 .cmp_encap = mpls_encap_cmp,
285 .owner = THIS_MODULE,
286};
287
288static int __init mpls_iptunnel_init(void)
289{
290 return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
291}
292module_init(mpls_iptunnel_init);
293
294static void __exit mpls_iptunnel_exit(void)
295{
296 lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
297}
298module_exit(mpls_iptunnel_exit);
299
300MODULE_ALIAS_RTNL_LWT(MPLS);
301MODULE_SOFTDEP("post: mpls_gso");
302MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels");
303MODULE_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_xmit(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_set_inner_protocol(skb, skb->protocol);
94 skb_reset_inner_network_header(skb);
95
96 skb_push(skb, new_header_size);
97
98 skb_reset_network_header(skb);
99
100 skb->dev = out_dev;
101 skb->protocol = htons(ETH_P_MPLS_UC);
102
103 /* Push the new labels */
104 hdr = mpls_hdr(skb);
105 bos = true;
106 for (i = tun_encap_info->labels - 1; i >= 0; i--) {
107 hdr[i] = mpls_entry_encode(tun_encap_info->label[i],
108 ttl, 0, bos);
109 bos = false;
110 }
111
112 if (rt)
113 err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway,
114 skb);
115 else if (rt6)
116 err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
117 skb);
118 if (err)
119 net_dbg_ratelimited("%s: packet transmission failed: %d\n",
120 __func__, err);
121
122 return LWTUNNEL_XMIT_DONE;
123
124drop:
125 kfree_skb(skb);
126 return -EINVAL;
127}
128
129static int mpls_build_state(struct net_device *dev, struct nlattr *nla,
130 unsigned int family, const void *cfg,
131 struct lwtunnel_state **ts)
132{
133 struct mpls_iptunnel_encap *tun_encap_info;
134 struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1];
135 struct lwtunnel_state *newts;
136 int ret;
137
138 ret = nla_parse_nested(tb, MPLS_IPTUNNEL_MAX, nla,
139 mpls_iptunnel_policy);
140 if (ret < 0)
141 return ret;
142
143 if (!tb[MPLS_IPTUNNEL_DST])
144 return -EINVAL;
145
146
147 newts = lwtunnel_state_alloc(sizeof(*tun_encap_info));
148 if (!newts)
149 return -ENOMEM;
150
151 tun_encap_info = mpls_lwtunnel_encap(newts);
152 ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS,
153 &tun_encap_info->labels, tun_encap_info->label);
154 if (ret)
155 goto errout;
156 newts->type = LWTUNNEL_ENCAP_MPLS;
157 newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
158 newts->headroom = mpls_encap_size(tun_encap_info);
159
160 *ts = newts;
161
162 return 0;
163
164errout:
165 kfree(newts);
166 *ts = NULL;
167
168 return ret;
169}
170
171static int mpls_fill_encap_info(struct sk_buff *skb,
172 struct lwtunnel_state *lwtstate)
173{
174 struct mpls_iptunnel_encap *tun_encap_info;
175
176 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
177
178 if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels,
179 tun_encap_info->label))
180 goto nla_put_failure;
181
182 return 0;
183
184nla_put_failure:
185 return -EMSGSIZE;
186}
187
188static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate)
189{
190 struct mpls_iptunnel_encap *tun_encap_info;
191
192 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
193
194 return nla_total_size(tun_encap_info->labels * 4);
195}
196
197static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
198{
199 struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a);
200 struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b);
201 int l;
202
203 if (a_hdr->labels != b_hdr->labels)
204 return 1;
205
206 for (l = 0; l < MAX_NEW_LABELS; l++)
207 if (a_hdr->label[l] != b_hdr->label[l])
208 return 1;
209 return 0;
210}
211
212static const struct lwtunnel_encap_ops mpls_iptun_ops = {
213 .build_state = mpls_build_state,
214 .xmit = mpls_xmit,
215 .fill_encap = mpls_fill_encap_info,
216 .get_encap_size = mpls_encap_nlsize,
217 .cmp_encap = mpls_encap_cmp,
218 .owner = THIS_MODULE,
219};
220
221static int __init mpls_iptunnel_init(void)
222{
223 return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
224}
225module_init(mpls_iptunnel_init);
226
227static void __exit mpls_iptunnel_exit(void)
228{
229 lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
230}
231module_exit(mpls_iptunnel_exit);
232
233MODULE_ALIAS_RTNL_LWT(MPLS);
234MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels");
235MODULE_LICENSE("GPL v2");