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 30 static const struct nla_policy mpls_iptunnel_policy[MPLS_IPTUNNEL_MAX + 1] = { 31 [MPLS_IPTUNNEL_DST] = { .type = NLA_U32 }, 32 }; 33 34 static 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 40 static 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 struct mpls_dev *out_mdev; 52 int err = 0; 53 bool bos; 54 int i; 55 unsigned int ttl; 56 57 /* Find the output device */ 58 out_dev = dst->dev; 59 60 /* Obtain the ttl */ 61 if (dst->ops->family == AF_INET) { 62 ttl = ip_hdr(skb)->ttl; 63 rt = (struct rtable *)dst; 64 } else if (dst->ops->family == AF_INET6) { 65 ttl = ipv6_hdr(skb)->hop_limit; 66 rt6 = (struct rt6_info *)dst; 67 } else { 68 goto drop; 69 } 70 71 skb_orphan(skb); 72 73 if (!mpls_output_possible(out_dev) || 74 !dst->lwtstate || skb_warn_if_lro(skb)) 75 goto drop; 76 77 skb_forward_csum(skb); 78 79 tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate); 80 81 /* Verify the destination can hold the packet */ 82 new_header_size = mpls_encap_size(tun_encap_info); 83 mtu = mpls_dev_mtu(out_dev); 84 if (mpls_pkt_too_big(skb, mtu - new_header_size)) 85 goto drop; 86 87 hh_len = LL_RESERVED_SPACE(out_dev); 88 if (!out_dev->header_ops) 89 hh_len = 0; 90 91 /* Ensure there is enough space for the headers in the skb */ 92 if (skb_cow(skb, hh_len + new_header_size)) 93 goto drop; 94 95 skb_set_inner_protocol(skb, skb->protocol); 96 skb_reset_inner_network_header(skb); 97 98 skb_push(skb, new_header_size); 99 100 skb_reset_network_header(skb); 101 102 skb->dev = out_dev; 103 skb->protocol = htons(ETH_P_MPLS_UC); 104 105 /* Push the new labels */ 106 hdr = mpls_hdr(skb); 107 bos = true; 108 for (i = tun_encap_info->labels - 1; i >= 0; i--) { 109 hdr[i] = mpls_entry_encode(tun_encap_info->label[i], 110 ttl, 0, bos); 111 bos = false; 112 } 113 114 mpls_stats_inc_outucastpkts(out_dev, skb); 115 116 if (rt) 117 err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway, 118 skb); 119 else if (rt6) 120 err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway, 121 skb); 122 if (err) 123 net_dbg_ratelimited("%s: packet transmission failed: %d\n", 124 __func__, err); 125 126 return LWTUNNEL_XMIT_DONE; 127 128 drop: 129 out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL; 130 if (out_mdev) 131 MPLS_INC_STATS(out_mdev, tx_errors); 132 kfree_skb(skb); 133 return -EINVAL; 134 } 135 136 static int mpls_build_state(struct nlattr *nla, 137 unsigned int family, const void *cfg, 138 struct lwtunnel_state **ts) 139 { 140 struct mpls_iptunnel_encap *tun_encap_info; 141 struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1]; 142 struct lwtunnel_state *newts; 143 int ret; 144 145 ret = nla_parse_nested(tb, MPLS_IPTUNNEL_MAX, nla, 146 mpls_iptunnel_policy); 147 if (ret < 0) 148 return ret; 149 150 if (!tb[MPLS_IPTUNNEL_DST]) 151 return -EINVAL; 152 153 154 newts = lwtunnel_state_alloc(sizeof(*tun_encap_info)); 155 if (!newts) 156 return -ENOMEM; 157 158 tun_encap_info = mpls_lwtunnel_encap(newts); 159 ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS, 160 &tun_encap_info->labels, tun_encap_info->label); 161 if (ret) 162 goto errout; 163 newts->type = LWTUNNEL_ENCAP_MPLS; 164 newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT; 165 newts->headroom = mpls_encap_size(tun_encap_info); 166 167 *ts = newts; 168 169 return 0; 170 171 errout: 172 kfree(newts); 173 *ts = NULL; 174 175 return ret; 176 } 177 178 static int mpls_fill_encap_info(struct sk_buff *skb, 179 struct lwtunnel_state *lwtstate) 180 { 181 struct mpls_iptunnel_encap *tun_encap_info; 182 183 tun_encap_info = mpls_lwtunnel_encap(lwtstate); 184 185 if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels, 186 tun_encap_info->label)) 187 goto nla_put_failure; 188 189 return 0; 190 191 nla_put_failure: 192 return -EMSGSIZE; 193 } 194 195 static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate) 196 { 197 struct mpls_iptunnel_encap *tun_encap_info; 198 199 tun_encap_info = mpls_lwtunnel_encap(lwtstate); 200 201 return nla_total_size(tun_encap_info->labels * 4); 202 } 203 204 static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b) 205 { 206 struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a); 207 struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b); 208 int l; 209 210 if (a_hdr->labels != b_hdr->labels) 211 return 1; 212 213 for (l = 0; l < MAX_NEW_LABELS; l++) 214 if (a_hdr->label[l] != b_hdr->label[l]) 215 return 1; 216 return 0; 217 } 218 219 static const struct lwtunnel_encap_ops mpls_iptun_ops = { 220 .build_state = mpls_build_state, 221 .xmit = mpls_xmit, 222 .fill_encap = mpls_fill_encap_info, 223 .get_encap_size = mpls_encap_nlsize, 224 .cmp_encap = mpls_encap_cmp, 225 .owner = THIS_MODULE, 226 }; 227 228 static int __init mpls_iptunnel_init(void) 229 { 230 return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS); 231 } 232 module_init(mpls_iptunnel_init); 233 234 static void __exit mpls_iptunnel_exit(void) 235 { 236 lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS); 237 } 238 module_exit(mpls_iptunnel_exit); 239 240 MODULE_ALIAS_RTNL_LWT(MPLS); 241 MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels"); 242 MODULE_LICENSE("GPL v2"); 243