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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
e3e4712e RP |
2 | /* |
3 | * mpls tunnels An implementation mpls tunnels using the light weight tunnel | |
4 | * infrastructure | |
5 | * | |
6 | * Authors: Roopa Prabhu, <roopa@cumulusnetworks.com> | |
e3e4712e RP |
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 | ||
25 | static const struct nla_policy mpls_iptunnel_policy[MPLS_IPTUNNEL_MAX + 1] = { | |
2f3f7d1f | 26 | [MPLS_IPTUNNEL_DST] = { .len = sizeof(u32) }, |
a59166e4 | 27 | [MPLS_IPTUNNEL_TTL] = { .type = NLA_U8 }, |
e3e4712e RP |
28 | }; |
29 | ||
30 | static 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 | ||
14972cbd | 36 | static int mpls_xmit(struct sk_buff *skb) |
e3e4712e RP |
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; | |
27d69105 | 47 | struct mpls_dev *out_mdev; |
a59166e4 | 48 | struct net *net; |
e3e4712e RP |
49 | int err = 0; |
50 | bool bos; | |
51 | int i; | |
52 | unsigned int ttl; | |
53 | ||
27d69105 RS |
54 | /* Find the output device */ |
55 | out_dev = dst->dev; | |
a59166e4 | 56 | net = dev_net(out_dev); |
e3e4712e RP |
57 | |
58 | skb_orphan(skb); | |
59 | ||
e3e4712e | 60 | if (!mpls_output_possible(out_dev) || |
61adedf3 | 61 | !dst->lwtstate || skb_warn_if_lro(skb)) |
e3e4712e RP |
62 | goto drop; |
63 | ||
64 | skb_forward_csum(skb); | |
65 | ||
61adedf3 | 66 | tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate); |
e3e4712e | 67 | |
a59166e4 RS |
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 | ||
e3e4712e RP |
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 | ||
48d2ab60 DA |
114 | skb_set_inner_protocol(skb, skb->protocol); |
115 | skb_reset_inner_network_header(skb); | |
116 | ||
e3e4712e | 117 | skb_push(skb, new_header_size); |
48d2ab60 | 118 | |
e3e4712e RP |
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 | ||
27d69105 RS |
133 | mpls_stats_inc_outucastpkts(out_dev, skb); |
134 | ||
1550c171 | 135 | if (rt) { |
803f3e22 | 136 | if (rt->rt_gw_family == AF_INET6) |
0f5f7d7b DA |
137 | err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt->rt_gw6, |
138 | skb); | |
803f3e22 AK |
139 | else |
140 | err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gw4, | |
141 | skb); | |
1550c171 | 142 | } else if (rt6) { |
f84532ce VN |
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 | } | |
e3e4712e RP |
151 | if (err) |
152 | net_dbg_ratelimited("%s: packet transmission failed: %d\n", | |
153 | __func__, err); | |
154 | ||
14972cbd | 155 | return LWTUNNEL_XMIT_DONE; |
e3e4712e RP |
156 | |
157 | drop: | |
27d69105 RS |
158 | out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL; |
159 | if (out_mdev) | |
160 | MPLS_INC_STATS(out_mdev, tx_errors); | |
e3e4712e RP |
161 | kfree_skb(skb); |
162 | return -EINVAL; | |
163 | } | |
164 | ||
30357d7d | 165 | static int mpls_build_state(struct nlattr *nla, |
127eb7cd | 166 | unsigned int family, const void *cfg, |
9ae28727 DA |
167 | struct lwtunnel_state **ts, |
168 | struct netlink_ext_ack *extack) | |
e3e4712e RP |
169 | { |
170 | struct mpls_iptunnel_encap *tun_encap_info; | |
171 | struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1]; | |
172 | struct lwtunnel_state *newts; | |
1511009c | 173 | u8 n_labels; |
e3e4712e RP |
174 | int ret; |
175 | ||
8cb08174 JB |
176 | ret = nla_parse_nested_deprecated(tb, MPLS_IPTUNNEL_MAX, nla, |
177 | mpls_iptunnel_policy, extack); | |
e3e4712e RP |
178 | if (ret < 0) |
179 | return ret; | |
180 | ||
a1f10abe DA |
181 | if (!tb[MPLS_IPTUNNEL_DST]) { |
182 | NL_SET_ERR_MSG(extack, "MPLS_IPTUNNEL_DST attribute is missing"); | |
e3e4712e | 183 | return -EINVAL; |
a1f10abe | 184 | } |
e3e4712e | 185 | |
1511009c | 186 | /* determine number of labels */ |
a1f10abe DA |
187 | if (nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS, |
188 | &n_labels, NULL, extack)) | |
1511009c DA |
189 | return -EINVAL; |
190 | ||
b4ba9354 GS |
191 | newts = lwtunnel_state_alloc(struct_size(tun_encap_info, label, |
192 | n_labels)); | |
e3e4712e RP |
193 | if (!newts) |
194 | return -ENOMEM; | |
195 | ||
e3e4712e | 196 | tun_encap_info = mpls_lwtunnel_encap(newts); |
1511009c | 197 | ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], n_labels, |
a1f10abe DA |
198 | &tun_encap_info->labels, tun_encap_info->label, |
199 | extack); | |
e3e4712e RP |
200 | if (ret) |
201 | goto errout; | |
a59166e4 RS |
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 | ||
e3e4712e | 213 | newts->type = LWTUNNEL_ENCAP_MPLS; |
14972cbd RP |
214 | newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT; |
215 | newts->headroom = mpls_encap_size(tun_encap_info); | |
e3e4712e RP |
216 | |
217 | *ts = newts; | |
218 | ||
219 | return 0; | |
220 | ||
221 | errout: | |
222 | kfree(newts); | |
223 | *ts = NULL; | |
224 | ||
225 | return ret; | |
226 | } | |
227 | ||
228 | static int mpls_fill_encap_info(struct sk_buff *skb, | |
229 | struct lwtunnel_state *lwtstate) | |
230 | { | |
231 | struct mpls_iptunnel_encap *tun_encap_info; | |
04c6a3a4 | 232 | |
e3e4712e RP |
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 | ||
a59166e4 RS |
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 | ||
e3e4712e RP |
243 | return 0; |
244 | ||
245 | nla_put_failure: | |
246 | return -EMSGSIZE; | |
247 | } | |
248 | ||
249 | static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate) | |
250 | { | |
251 | struct mpls_iptunnel_encap *tun_encap_info; | |
a59166e4 | 252 | int nlsize; |
e3e4712e RP |
253 | |
254 | tun_encap_info = mpls_lwtunnel_encap(lwtstate); | |
255 | ||
a59166e4 RS |
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; | |
e3e4712e RP |
262 | } |
263 | ||
264 | static 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 | ||
a59166e4 RS |
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) | |
e3e4712e RP |
273 | return 1; |
274 | ||
1511009c | 275 | for (l = 0; l < a_hdr->labels; l++) |
e3e4712e RP |
276 | if (a_hdr->label[l] != b_hdr->label[l]) |
277 | return 1; | |
278 | return 0; | |
279 | } | |
280 | ||
281 | static const struct lwtunnel_encap_ops mpls_iptun_ops = { | |
282 | .build_state = mpls_build_state, | |
14972cbd | 283 | .xmit = mpls_xmit, |
e3e4712e RP |
284 | .fill_encap = mpls_fill_encap_info, |
285 | .get_encap_size = mpls_encap_nlsize, | |
286 | .cmp_encap = mpls_encap_cmp, | |
88ff7334 | 287 | .owner = THIS_MODULE, |
e3e4712e RP |
288 | }; |
289 | ||
290 | static int __init mpls_iptunnel_init(void) | |
291 | { | |
292 | return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS); | |
293 | } | |
294 | module_init(mpls_iptunnel_init); | |
295 | ||
296 | static void __exit mpls_iptunnel_exit(void) | |
297 | { | |
298 | lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS); | |
299 | } | |
300 | module_exit(mpls_iptunnel_exit); | |
301 | ||
b2b04edc | 302 | MODULE_ALIAS_RTNL_LWT(MPLS); |
e3e4712e RP |
303 | MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels"); |
304 | MODULE_LICENSE("GPL v2"); |