1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * mpls tunnels An implementation mpls tunnels using the light weight tunnel
6 * Authors: Roopa Prabhu, <roopa@cumulusnetworks.com>
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>
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>
25 static 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 },
30 static unsigned int mpls_encap_size(struct mpls_iptunnel_encap *en)
32 /* The size of the layer 2.5 labels to be added for this route */
33 return en->labels * sizeof(struct mpls_shim_hdr);
36 static int mpls_xmit(struct sk_buff *skb)
38 struct mpls_iptunnel_encap *tun_encap_info;
39 struct mpls_shim_hdr *hdr;
40 struct net_device *out_dev;
42 unsigned int new_header_size;
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;
54 /* Find the output device */
56 net = dev_net(out_dev);
58 if (!mpls_output_possible(out_dev) ||
59 !dst->lwtstate || skb_warn_if_lro(skb))
62 skb_forward_csum(skb);
64 tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate);
66 /* Obtain the ttl using the following set of rules.
68 * LWT ttl propagation setting:
69 * - disabled => use default TTL value from LWT
70 * - enabled => use TTL value from IPv4/IPv6 header
72 * Global ttl propagation setting:
73 * - disabled => use default TTL value from global setting
74 * - enabled => use TTL value from IPv4/IPv6 header
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;
83 ttl = ip_hdr(skb)->ttl;
84 rt = (struct 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;
92 ttl = ipv6_hdr(skb)->hop_limit;
93 rt6 = (struct rt6_info *)dst;
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))
104 hh_len = LL_RESERVED_SPACE(out_dev);
105 if (!out_dev->header_ops)
108 /* Ensure there is enough space for the headers in the skb */
109 if (skb_cow(skb, hh_len + new_header_size))
112 skb_set_inner_protocol(skb, skb->protocol);
113 skb_reset_inner_network_header(skb);
115 skb_push(skb, new_header_size);
117 skb_reset_network_header(skb);
120 skb->protocol = htons(ETH_P_MPLS_UC);
122 /* Push the new labels */
125 for (i = tun_encap_info->labels - 1; i >= 0; i--) {
126 hdr[i] = mpls_entry_encode(tun_encap_info->label[i],
131 mpls_stats_inc_outucastpkts(out_dev, skb);
134 if (rt->rt_gw_family == AF_INET6)
135 err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt->rt_gw6,
138 err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gw4,
141 if (ipv6_addr_v4mapped(&rt6->rt6i_gateway)) {
143 err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt6->rt6i_gateway.s6_addr32[3],
146 err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
150 net_dbg_ratelimited("%s: packet transmission failed: %d\n",
153 return LWTUNNEL_XMIT_DONE;
156 out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;
158 MPLS_INC_STATS(out_mdev, tx_errors);
163 static 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)
168 struct mpls_iptunnel_encap *tun_encap_info;
169 struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1];
170 struct lwtunnel_state *newts;
174 ret = nla_parse_nested_deprecated(tb, MPLS_IPTUNNEL_MAX, nla,
175 mpls_iptunnel_policy, extack);
179 if (!tb[MPLS_IPTUNNEL_DST]) {
180 NL_SET_ERR_MSG(extack, "MPLS_IPTUNNEL_DST attribute is missing");
184 /* determine number of labels */
185 if (nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS,
186 &n_labels, NULL, extack))
189 newts = lwtunnel_state_alloc(struct_size(tun_encap_info, label,
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,
201 tun_encap_info->ttl_propagate = MPLS_TTL_PROP_DEFAULT;
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;
211 newts->type = LWTUNNEL_ENCAP_MPLS;
212 newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
213 newts->headroom = mpls_encap_size(tun_encap_info);
226 static int mpls_fill_encap_info(struct sk_buff *skb,
227 struct lwtunnel_state *lwtstate)
229 struct mpls_iptunnel_encap *tun_encap_info;
231 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
233 if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels,
234 tun_encap_info->label))
235 goto nla_put_failure;
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;
247 static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate)
249 struct mpls_iptunnel_encap *tun_encap_info;
252 tun_encap_info = mpls_lwtunnel_encap(lwtstate);
254 nlsize = nla_total_size(tun_encap_info->labels * 4);
256 if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT)
257 nlsize += nla_total_size(1);
262 static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
264 struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a);
265 struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b);
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)
273 for (l = 0; l < a_hdr->labels; l++)
274 if (a_hdr->label[l] != b_hdr->label[l])
279 static const struct lwtunnel_encap_ops mpls_iptun_ops = {
280 .build_state = mpls_build_state,
282 .fill_encap = mpls_fill_encap_info,
283 .get_encap_size = mpls_encap_nlsize,
284 .cmp_encap = mpls_encap_cmp,
285 .owner = THIS_MODULE,
288 static int __init mpls_iptunnel_init(void)
290 return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
292 module_init(mpls_iptunnel_init);
294 static void __exit mpls_iptunnel_exit(void)
296 lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
298 module_exit(mpls_iptunnel_exit);
300 MODULE_ALIAS_RTNL_LWT(MPLS);
301 MODULE_SOFTDEP("post: mpls_gso");
302 MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels");
303 MODULE_LICENSE("GPL v2");