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| 1 | +/* |
| 2 | + * mpls tunnels An implementation mpls tunnels using the light weight tunnel |
| 3 | + * infrastructure |
| 4 | + * |
| 5 | + * Authors: Roopa Prabhu, <[email protected]> |
| 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 | +int mpls_output(struct sock *sk, 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 lwtunnel_state *lwtstate = NULL; |
| 52 | + int err = 0; |
| 53 | + bool bos; |
| 54 | + int i; |
| 55 | + unsigned int ttl; |
| 56 | + |
| 57 | + /* Obtain the ttl */ |
| 58 | + if (skb->protocol == htons(ETH_P_IP)) { |
| 59 | + ttl = ip_hdr(skb)->ttl; |
| 60 | + rt = (struct rtable *)dst; |
| 61 | + lwtstate = rt->rt_lwtstate; |
| 62 | + } else if (skb->protocol == htons(ETH_P_IPV6)) { |
| 63 | + ttl = ipv6_hdr(skb)->hop_limit; |
| 64 | + rt6 = (struct rt6_info *)dst; |
| 65 | + lwtstate = rt6->rt6i_lwtstate; |
| 66 | + } else { |
| 67 | + goto drop; |
| 68 | + } |
| 69 | + |
| 70 | + skb_orphan(skb); |
| 71 | + |
| 72 | + /* Find the output device */ |
| 73 | + out_dev = rcu_dereference(dst->dev); |
| 74 | + if (!mpls_output_possible(out_dev) || |
| 75 | + !lwtstate || skb_warn_if_lro(skb)) |
| 76 | + goto drop; |
| 77 | + |
| 78 | + skb_forward_csum(skb); |
| 79 | + |
| 80 | + tun_encap_info = mpls_lwtunnel_encap(lwtstate); |
| 81 | + |
| 82 | + /* Verify the destination can hold the packet */ |
| 83 | + new_header_size = mpls_encap_size(tun_encap_info); |
| 84 | + mtu = mpls_dev_mtu(out_dev); |
| 85 | + if (mpls_pkt_too_big(skb, mtu - new_header_size)) |
| 86 | + goto drop; |
| 87 | + |
| 88 | + hh_len = LL_RESERVED_SPACE(out_dev); |
| 89 | + if (!out_dev->header_ops) |
| 90 | + hh_len = 0; |
| 91 | + |
| 92 | + /* Ensure there is enough space for the headers in the skb */ |
| 93 | + if (skb_cow(skb, hh_len + new_header_size)) |
| 94 | + goto drop; |
| 95 | + |
| 96 | + skb_push(skb, new_header_size); |
| 97 | + skb_reset_network_header(skb); |
| 98 | + |
| 99 | + skb->dev = out_dev; |
| 100 | + skb->protocol = htons(ETH_P_MPLS_UC); |
| 101 | + |
| 102 | + /* Push the new labels */ |
| 103 | + hdr = mpls_hdr(skb); |
| 104 | + bos = true; |
| 105 | + for (i = tun_encap_info->labels - 1; i >= 0; i--) { |
| 106 | + hdr[i] = mpls_entry_encode(tun_encap_info->label[i], |
| 107 | + ttl, 0, bos); |
| 108 | + bos = false; |
| 109 | + } |
| 110 | + |
| 111 | + if (rt) |
| 112 | + err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway, |
| 113 | + skb); |
| 114 | + else if (rt6) |
| 115 | + err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway, |
| 116 | + skb); |
| 117 | + if (err) |
| 118 | + net_dbg_ratelimited("%s: packet transmission failed: %d\n", |
| 119 | + __func__, err); |
| 120 | + |
| 121 | + return 0; |
| 122 | + |
| 123 | +drop: |
| 124 | + kfree_skb(skb); |
| 125 | + return -EINVAL; |
| 126 | +} |
| 127 | + |
| 128 | +static int mpls_build_state(struct net_device *dev, struct nlattr *nla, |
| 129 | + struct lwtunnel_state **ts) |
| 130 | +{ |
| 131 | + struct mpls_iptunnel_encap *tun_encap_info; |
| 132 | + struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1]; |
| 133 | + struct lwtunnel_state *newts; |
| 134 | + int tun_encap_info_len; |
| 135 | + int ret; |
| 136 | + |
| 137 | + ret = nla_parse_nested(tb, MPLS_IPTUNNEL_MAX, nla, |
| 138 | + mpls_iptunnel_policy); |
| 139 | + if (ret < 0) |
| 140 | + return ret; |
| 141 | + |
| 142 | + if (!tb[MPLS_IPTUNNEL_DST]) |
| 143 | + return -EINVAL; |
| 144 | + |
| 145 | + tun_encap_info_len = sizeof(*tun_encap_info); |
| 146 | + |
| 147 | + newts = lwtunnel_state_alloc(tun_encap_info_len); |
| 148 | + if (!newts) |
| 149 | + return -ENOMEM; |
| 150 | + |
| 151 | + newts->len = tun_encap_info_len; |
| 152 | + tun_encap_info = mpls_lwtunnel_encap(newts); |
| 153 | + ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS, |
| 154 | + &tun_encap_info->labels, tun_encap_info->label); |
| 155 | + if (ret) |
| 156 | + goto errout; |
| 157 | + newts->type = LWTUNNEL_ENCAP_MPLS; |
| 158 | + newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT; |
| 159 | + |
| 160 | + *ts = newts; |
| 161 | + |
| 162 | + return 0; |
| 163 | + |
| 164 | +errout: |
| 165 | + kfree(newts); |
| 166 | + *ts = NULL; |
| 167 | + |
| 168 | + return ret; |
| 169 | +} |
| 170 | + |
| 171 | +static int mpls_fill_encap_info(struct sk_buff *skb, |
| 172 | + struct lwtunnel_state *lwtstate) |
| 173 | +{ |
| 174 | + struct mpls_iptunnel_encap *tun_encap_info; |
| 175 | + |
| 176 | + tun_encap_info = mpls_lwtunnel_encap(lwtstate); |
| 177 | + |
| 178 | + if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels, |
| 179 | + tun_encap_info->label)) |
| 180 | + goto nla_put_failure; |
| 181 | + |
| 182 | + return 0; |
| 183 | + |
| 184 | +nla_put_failure: |
| 185 | + return -EMSGSIZE; |
| 186 | +} |
| 187 | + |
| 188 | +static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate) |
| 189 | +{ |
| 190 | + struct mpls_iptunnel_encap *tun_encap_info; |
| 191 | + |
| 192 | + tun_encap_info = mpls_lwtunnel_encap(lwtstate); |
| 193 | + |
| 194 | + return nla_total_size(tun_encap_info->labels * 4); |
| 195 | +} |
| 196 | + |
| 197 | +static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b) |
| 198 | +{ |
| 199 | + struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a); |
| 200 | + struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b); |
| 201 | + int l; |
| 202 | + |
| 203 | + if (a_hdr->labels != b_hdr->labels) |
| 204 | + return 1; |
| 205 | + |
| 206 | + for (l = 0; l < MAX_NEW_LABELS; l++) |
| 207 | + if (a_hdr->label[l] != b_hdr->label[l]) |
| 208 | + return 1; |
| 209 | + return 0; |
| 210 | +} |
| 211 | + |
| 212 | +static const struct lwtunnel_encap_ops mpls_iptun_ops = { |
| 213 | + .build_state = mpls_build_state, |
| 214 | + .output = mpls_output, |
| 215 | + .fill_encap = mpls_fill_encap_info, |
| 216 | + .get_encap_size = mpls_encap_nlsize, |
| 217 | + .cmp_encap = mpls_encap_cmp, |
| 218 | +}; |
| 219 | + |
| 220 | +static int __init mpls_iptunnel_init(void) |
| 221 | +{ |
| 222 | + return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS); |
| 223 | +} |
| 224 | +module_init(mpls_iptunnel_init); |
| 225 | + |
| 226 | +static void __exit mpls_iptunnel_exit(void) |
| 227 | +{ |
| 228 | + lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS); |
| 229 | +} |
| 230 | +module_exit(mpls_iptunnel_exit); |
| 231 | + |
| 232 | +MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels"); |
| 233 | +MODULE_LICENSE("GPL v2"); |
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