1e3e4712eSRoopa Prabhu /* 2e3e4712eSRoopa Prabhu * mpls tunnels An implementation mpls tunnels using the light weight tunnel 3e3e4712eSRoopa Prabhu * infrastructure 4e3e4712eSRoopa Prabhu * 5e3e4712eSRoopa Prabhu * Authors: Roopa Prabhu, <roopa@cumulusnetworks.com> 6e3e4712eSRoopa Prabhu * 7e3e4712eSRoopa Prabhu * This program is free software; you can redistribute it and/or 8e3e4712eSRoopa Prabhu * modify it under the terms of the GNU General Public License 9e3e4712eSRoopa Prabhu * as published by the Free Software Foundation; either version 10e3e4712eSRoopa Prabhu * 2 of the License, or (at your option) any later version. 11e3e4712eSRoopa Prabhu * 12e3e4712eSRoopa Prabhu */ 13e3e4712eSRoopa Prabhu #include <linux/types.h> 14e3e4712eSRoopa Prabhu #include <linux/skbuff.h> 15e3e4712eSRoopa Prabhu #include <linux/net.h> 16e3e4712eSRoopa Prabhu #include <linux/module.h> 17e3e4712eSRoopa Prabhu #include <linux/mpls.h> 18e3e4712eSRoopa Prabhu #include <linux/vmalloc.h> 19e3e4712eSRoopa Prabhu #include <net/ip.h> 20e3e4712eSRoopa Prabhu #include <net/dst.h> 21e3e4712eSRoopa Prabhu #include <net/lwtunnel.h> 22e3e4712eSRoopa Prabhu #include <net/netevent.h> 23e3e4712eSRoopa Prabhu #include <net/netns/generic.h> 24e3e4712eSRoopa Prabhu #include <net/ip6_fib.h> 25e3e4712eSRoopa Prabhu #include <net/route.h> 26e3e4712eSRoopa Prabhu #include <net/mpls_iptunnel.h> 27e3e4712eSRoopa Prabhu #include <linux/mpls_iptunnel.h> 28e3e4712eSRoopa Prabhu #include "internal.h" 29e3e4712eSRoopa Prabhu 30e3e4712eSRoopa Prabhu static const struct nla_policy mpls_iptunnel_policy[MPLS_IPTUNNEL_MAX + 1] = { 31e3e4712eSRoopa Prabhu [MPLS_IPTUNNEL_DST] = { .type = NLA_U32 }, 32e3e4712eSRoopa Prabhu }; 33e3e4712eSRoopa Prabhu 34e3e4712eSRoopa Prabhu static unsigned int mpls_encap_size(struct mpls_iptunnel_encap *en) 35e3e4712eSRoopa Prabhu { 36e3e4712eSRoopa Prabhu /* The size of the layer 2.5 labels to be added for this route */ 37e3e4712eSRoopa Prabhu return en->labels * sizeof(struct mpls_shim_hdr); 38e3e4712eSRoopa Prabhu } 39e3e4712eSRoopa Prabhu 40e3e4712eSRoopa Prabhu int mpls_output(struct sock *sk, struct sk_buff *skb) 41e3e4712eSRoopa Prabhu { 42e3e4712eSRoopa Prabhu struct mpls_iptunnel_encap *tun_encap_info; 43e3e4712eSRoopa Prabhu struct mpls_shim_hdr *hdr; 44e3e4712eSRoopa Prabhu struct net_device *out_dev; 45e3e4712eSRoopa Prabhu unsigned int hh_len; 46e3e4712eSRoopa Prabhu unsigned int new_header_size; 47e3e4712eSRoopa Prabhu unsigned int mtu; 48e3e4712eSRoopa Prabhu struct dst_entry *dst = skb_dst(skb); 49e3e4712eSRoopa Prabhu struct rtable *rt = NULL; 50e3e4712eSRoopa Prabhu struct rt6_info *rt6 = NULL; 51e3e4712eSRoopa Prabhu struct lwtunnel_state *lwtstate = NULL; 52e3e4712eSRoopa Prabhu int err = 0; 53e3e4712eSRoopa Prabhu bool bos; 54e3e4712eSRoopa Prabhu int i; 55e3e4712eSRoopa Prabhu unsigned int ttl; 56e3e4712eSRoopa Prabhu 57e3e4712eSRoopa Prabhu /* Obtain the ttl */ 58e3e4712eSRoopa Prabhu if (skb->protocol == htons(ETH_P_IP)) { 59e3e4712eSRoopa Prabhu ttl = ip_hdr(skb)->ttl; 60e3e4712eSRoopa Prabhu rt = (struct rtable *)dst; 61e3e4712eSRoopa Prabhu lwtstate = rt->rt_lwtstate; 62e3e4712eSRoopa Prabhu } else if (skb->protocol == htons(ETH_P_IPV6)) { 63e3e4712eSRoopa Prabhu ttl = ipv6_hdr(skb)->hop_limit; 64e3e4712eSRoopa Prabhu rt6 = (struct rt6_info *)dst; 65e3e4712eSRoopa Prabhu lwtstate = rt6->rt6i_lwtstate; 66e3e4712eSRoopa Prabhu } else { 67e3e4712eSRoopa Prabhu goto drop; 68e3e4712eSRoopa Prabhu } 69e3e4712eSRoopa Prabhu 70e3e4712eSRoopa Prabhu skb_orphan(skb); 71e3e4712eSRoopa Prabhu 72e3e4712eSRoopa Prabhu /* Find the output device */ 73e3e4712eSRoopa Prabhu out_dev = rcu_dereference(dst->dev); 74e3e4712eSRoopa Prabhu if (!mpls_output_possible(out_dev) || 75e3e4712eSRoopa Prabhu !lwtstate || skb_warn_if_lro(skb)) 76e3e4712eSRoopa Prabhu goto drop; 77e3e4712eSRoopa Prabhu 78e3e4712eSRoopa Prabhu skb_forward_csum(skb); 79e3e4712eSRoopa Prabhu 80e3e4712eSRoopa Prabhu tun_encap_info = mpls_lwtunnel_encap(lwtstate); 81e3e4712eSRoopa Prabhu 82e3e4712eSRoopa Prabhu /* Verify the destination can hold the packet */ 83e3e4712eSRoopa Prabhu new_header_size = mpls_encap_size(tun_encap_info); 84e3e4712eSRoopa Prabhu mtu = mpls_dev_mtu(out_dev); 85e3e4712eSRoopa Prabhu if (mpls_pkt_too_big(skb, mtu - new_header_size)) 86e3e4712eSRoopa Prabhu goto drop; 87e3e4712eSRoopa Prabhu 88e3e4712eSRoopa Prabhu hh_len = LL_RESERVED_SPACE(out_dev); 89e3e4712eSRoopa Prabhu if (!out_dev->header_ops) 90e3e4712eSRoopa Prabhu hh_len = 0; 91e3e4712eSRoopa Prabhu 92e3e4712eSRoopa Prabhu /* Ensure there is enough space for the headers in the skb */ 93e3e4712eSRoopa Prabhu if (skb_cow(skb, hh_len + new_header_size)) 94e3e4712eSRoopa Prabhu goto drop; 95e3e4712eSRoopa Prabhu 96e3e4712eSRoopa Prabhu skb_push(skb, new_header_size); 97e3e4712eSRoopa Prabhu skb_reset_network_header(skb); 98e3e4712eSRoopa Prabhu 99e3e4712eSRoopa Prabhu skb->dev = out_dev; 100e3e4712eSRoopa Prabhu skb->protocol = htons(ETH_P_MPLS_UC); 101e3e4712eSRoopa Prabhu 102e3e4712eSRoopa Prabhu /* Push the new labels */ 103e3e4712eSRoopa Prabhu hdr = mpls_hdr(skb); 104e3e4712eSRoopa Prabhu bos = true; 105e3e4712eSRoopa Prabhu for (i = tun_encap_info->labels - 1; i >= 0; i--) { 106e3e4712eSRoopa Prabhu hdr[i] = mpls_entry_encode(tun_encap_info->label[i], 107e3e4712eSRoopa Prabhu ttl, 0, bos); 108e3e4712eSRoopa Prabhu bos = false; 109e3e4712eSRoopa Prabhu } 110e3e4712eSRoopa Prabhu 111e3e4712eSRoopa Prabhu if (rt) 112e3e4712eSRoopa Prabhu err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway, 113e3e4712eSRoopa Prabhu skb); 114e3e4712eSRoopa Prabhu else if (rt6) 115e3e4712eSRoopa Prabhu err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway, 116e3e4712eSRoopa Prabhu skb); 117e3e4712eSRoopa Prabhu if (err) 118e3e4712eSRoopa Prabhu net_dbg_ratelimited("%s: packet transmission failed: %d\n", 119e3e4712eSRoopa Prabhu __func__, err); 120e3e4712eSRoopa Prabhu 121e3e4712eSRoopa Prabhu return 0; 122e3e4712eSRoopa Prabhu 123e3e4712eSRoopa Prabhu drop: 124e3e4712eSRoopa Prabhu kfree_skb(skb); 125e3e4712eSRoopa Prabhu return -EINVAL; 126e3e4712eSRoopa Prabhu } 127e3e4712eSRoopa Prabhu 128e3e4712eSRoopa Prabhu static int mpls_build_state(struct net_device *dev, struct nlattr *nla, 129e3e4712eSRoopa Prabhu struct lwtunnel_state **ts) 130e3e4712eSRoopa Prabhu { 131e3e4712eSRoopa Prabhu struct mpls_iptunnel_encap *tun_encap_info; 132e3e4712eSRoopa Prabhu struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1]; 133e3e4712eSRoopa Prabhu struct lwtunnel_state *newts; 134e3e4712eSRoopa Prabhu int tun_encap_info_len; 135e3e4712eSRoopa Prabhu int ret; 136e3e4712eSRoopa Prabhu 137e3e4712eSRoopa Prabhu ret = nla_parse_nested(tb, MPLS_IPTUNNEL_MAX, nla, 138e3e4712eSRoopa Prabhu mpls_iptunnel_policy); 139e3e4712eSRoopa Prabhu if (ret < 0) 140e3e4712eSRoopa Prabhu return ret; 141e3e4712eSRoopa Prabhu 142e3e4712eSRoopa Prabhu if (!tb[MPLS_IPTUNNEL_DST]) 143e3e4712eSRoopa Prabhu return -EINVAL; 144e3e4712eSRoopa Prabhu 145e3e4712eSRoopa Prabhu tun_encap_info_len = sizeof(*tun_encap_info); 146e3e4712eSRoopa Prabhu 147e3e4712eSRoopa Prabhu newts = lwtunnel_state_alloc(tun_encap_info_len); 148e3e4712eSRoopa Prabhu if (!newts) 149e3e4712eSRoopa Prabhu return -ENOMEM; 150e3e4712eSRoopa Prabhu 151e3e4712eSRoopa Prabhu newts->len = tun_encap_info_len; 152e3e4712eSRoopa Prabhu tun_encap_info = mpls_lwtunnel_encap(newts); 153e3e4712eSRoopa Prabhu ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS, 154e3e4712eSRoopa Prabhu &tun_encap_info->labels, tun_encap_info->label); 155e3e4712eSRoopa Prabhu if (ret) 156e3e4712eSRoopa Prabhu goto errout; 157e3e4712eSRoopa Prabhu newts->type = LWTUNNEL_ENCAP_MPLS; 158e3e4712eSRoopa Prabhu newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT; 159e3e4712eSRoopa Prabhu 160e3e4712eSRoopa Prabhu *ts = newts; 161e3e4712eSRoopa Prabhu 162e3e4712eSRoopa Prabhu return 0; 163e3e4712eSRoopa Prabhu 164e3e4712eSRoopa Prabhu errout: 165e3e4712eSRoopa Prabhu kfree(newts); 166e3e4712eSRoopa Prabhu *ts = NULL; 167e3e4712eSRoopa Prabhu 168e3e4712eSRoopa Prabhu return ret; 169e3e4712eSRoopa Prabhu } 170e3e4712eSRoopa Prabhu 171e3e4712eSRoopa Prabhu static int mpls_fill_encap_info(struct sk_buff *skb, 172e3e4712eSRoopa Prabhu struct lwtunnel_state *lwtstate) 173e3e4712eSRoopa Prabhu { 174e3e4712eSRoopa Prabhu struct mpls_iptunnel_encap *tun_encap_info; 175e3e4712eSRoopa Prabhu 176e3e4712eSRoopa Prabhu tun_encap_info = mpls_lwtunnel_encap(lwtstate); 177e3e4712eSRoopa Prabhu 178e3e4712eSRoopa Prabhu if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels, 179e3e4712eSRoopa Prabhu tun_encap_info->label)) 180e3e4712eSRoopa Prabhu goto nla_put_failure; 181e3e4712eSRoopa Prabhu 182e3e4712eSRoopa Prabhu return 0; 183e3e4712eSRoopa Prabhu 184e3e4712eSRoopa Prabhu nla_put_failure: 185e3e4712eSRoopa Prabhu return -EMSGSIZE; 186e3e4712eSRoopa Prabhu } 187e3e4712eSRoopa Prabhu 188e3e4712eSRoopa Prabhu static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate) 189e3e4712eSRoopa Prabhu { 190e3e4712eSRoopa Prabhu struct mpls_iptunnel_encap *tun_encap_info; 191e3e4712eSRoopa Prabhu 192e3e4712eSRoopa Prabhu tun_encap_info = mpls_lwtunnel_encap(lwtstate); 193e3e4712eSRoopa Prabhu 194e3e4712eSRoopa Prabhu return nla_total_size(tun_encap_info->labels * 4); 195e3e4712eSRoopa Prabhu } 196e3e4712eSRoopa Prabhu 197e3e4712eSRoopa Prabhu static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b) 198e3e4712eSRoopa Prabhu { 199e3e4712eSRoopa Prabhu struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a); 200e3e4712eSRoopa Prabhu struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b); 201e3e4712eSRoopa Prabhu int l; 202e3e4712eSRoopa Prabhu 203e3e4712eSRoopa Prabhu if (a_hdr->labels != b_hdr->labels) 204e3e4712eSRoopa Prabhu return 1; 205e3e4712eSRoopa Prabhu 206e3e4712eSRoopa Prabhu for (l = 0; l < MAX_NEW_LABELS; l++) 207e3e4712eSRoopa Prabhu if (a_hdr->label[l] != b_hdr->label[l]) 208e3e4712eSRoopa Prabhu return 1; 209e3e4712eSRoopa Prabhu return 0; 210e3e4712eSRoopa Prabhu } 211e3e4712eSRoopa Prabhu 212e3e4712eSRoopa Prabhu static const struct lwtunnel_encap_ops mpls_iptun_ops = { 213e3e4712eSRoopa Prabhu .build_state = mpls_build_state, 214e3e4712eSRoopa Prabhu .output = mpls_output, 215e3e4712eSRoopa Prabhu .fill_encap = mpls_fill_encap_info, 216e3e4712eSRoopa Prabhu .get_encap_size = mpls_encap_nlsize, 217e3e4712eSRoopa Prabhu .cmp_encap = mpls_encap_cmp, 218e3e4712eSRoopa Prabhu }; 219e3e4712eSRoopa Prabhu 220e3e4712eSRoopa Prabhu static int __init mpls_iptunnel_init(void) 221e3e4712eSRoopa Prabhu { 222e3e4712eSRoopa Prabhu return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS); 223e3e4712eSRoopa Prabhu } 224e3e4712eSRoopa Prabhu module_init(mpls_iptunnel_init); 225e3e4712eSRoopa Prabhu 226e3e4712eSRoopa Prabhu static void __exit mpls_iptunnel_exit(void) 227e3e4712eSRoopa Prabhu { 228e3e4712eSRoopa Prabhu lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS); 229e3e4712eSRoopa Prabhu } 230e3e4712eSRoopa Prabhu module_exit(mpls_iptunnel_exit); 231e3e4712eSRoopa Prabhu 232e3e4712eSRoopa Prabhu MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels"); 233e3e4712eSRoopa Prabhu MODULE_LICENSE("GPL v2"); 234