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Roopa Prabhue3e47122015-07-21 10:43:53 +02001/*
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
Eric W. Biedermanede20592015-10-07 16:48:47 -050040int mpls_output(struct net *net, struct sock *sk, struct sk_buff *skb)
Roopa Prabhue3e47122015-07-21 10:43:53 +020041{
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;
Roopa Prabhue3e47122015-07-21 10:43:53 +020051 int err = 0;
52 bool bos;
53 int i;
54 unsigned int ttl;
55
56 /* Obtain the ttl */
57 if (skb->protocol == htons(ETH_P_IP)) {
58 ttl = ip_hdr(skb)->ttl;
59 rt = (struct rtable *)dst;
Roopa Prabhue3e47122015-07-21 10:43:53 +020060 } else if (skb->protocol == htons(ETH_P_IPV6)) {
61 ttl = ipv6_hdr(skb)->hop_limit;
62 rt6 = (struct rt6_info *)dst;
Roopa Prabhue3e47122015-07-21 10:43:53 +020063 } else {
64 goto drop;
65 }
66
67 skb_orphan(skb);
68
69 /* Find the output device */
Roopa Prabhude185472015-07-21 22:49:00 -070070 out_dev = dst->dev;
Roopa Prabhue3e47122015-07-21 10:43:53 +020071 if (!mpls_output_possible(out_dev) ||
Jiri Benc61adedf2015-08-20 13:56:25 +020072 !dst->lwtstate || skb_warn_if_lro(skb))
Roopa Prabhue3e47122015-07-21 10:43:53 +020073 goto drop;
74
75 skb_forward_csum(skb);
76
Jiri Benc61adedf2015-08-20 13:56:25 +020077 tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate);
Roopa Prabhue3e47122015-07-21 10:43:53 +020078
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,
Tom Herbert127eb7c2015-08-24 09:45:41 -0700126 unsigned int family, const void *cfg,
Roopa Prabhue3e47122015-07-21 10:43:53 +0200127 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_DESCRIPTION("MultiProtocol Label Switching IP Tunnels");
231MODULE_LICENSE("GPL v2");