300 lines
7.7 KiB
C
300 lines
7.7 KiB
C
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/*
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* mpls tunnels An implementation mpls tunnels using the light weight tunnel
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* infrastructure
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*
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* Authors: Roopa Prabhu, <roopa@cumulusnetworks.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/types.h>
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#include <linux/skbuff.h>
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#include <linux/net.h>
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#include <linux/module.h>
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#include <linux/mpls.h>
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#include <linux/vmalloc.h>
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#include <net/ip.h>
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#include <net/dst.h>
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#include <net/lwtunnel.h>
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#include <net/netevent.h>
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#include <net/netns/generic.h>
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#include <net/ip6_fib.h>
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#include <net/route.h>
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#include <net/mpls_iptunnel.h>
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#include <linux/mpls_iptunnel.h>
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#include "internal.h"
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static const struct nla_policy mpls_iptunnel_policy[MPLS_IPTUNNEL_MAX + 1] = {
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[MPLS_IPTUNNEL_DST] = { .len = sizeof(u32) },
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[MPLS_IPTUNNEL_TTL] = { .type = NLA_U8 },
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};
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static unsigned int mpls_encap_size(struct mpls_iptunnel_encap *en)
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{
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/* The size of the layer 2.5 labels to be added for this route */
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return en->labels * sizeof(struct mpls_shim_hdr);
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}
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static int mpls_xmit(struct sk_buff *skb)
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{
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struct mpls_iptunnel_encap *tun_encap_info;
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struct mpls_shim_hdr *hdr;
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struct net_device *out_dev;
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unsigned int hh_len;
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unsigned int new_header_size;
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unsigned int mtu;
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struct dst_entry *dst = skb_dst(skb);
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struct rtable *rt = NULL;
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struct rt6_info *rt6 = NULL;
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struct mpls_dev *out_mdev;
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struct net *net;
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int err = 0;
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bool bos;
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int i;
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unsigned int ttl;
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/* Find the output device */
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out_dev = dst->dev;
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net = dev_net(out_dev);
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skb_orphan(skb);
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if (!mpls_output_possible(out_dev) ||
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!dst->lwtstate || skb_warn_if_lro(skb))
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goto drop;
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skb_forward_csum(skb);
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tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate);
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/* Obtain the ttl using the following set of rules.
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*
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* LWT ttl propagation setting:
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* - disabled => use default TTL value from LWT
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* - enabled => use TTL value from IPv4/IPv6 header
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* - default =>
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* Global ttl propagation setting:
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* - disabled => use default TTL value from global setting
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* - enabled => use TTL value from IPv4/IPv6 header
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*/
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if (dst->ops->family == AF_INET) {
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if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
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ttl = tun_encap_info->default_ttl;
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else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
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!net->mpls.ip_ttl_propagate)
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ttl = net->mpls.default_ttl;
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else
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ttl = ip_hdr(skb)->ttl;
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rt = (struct rtable *)dst;
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} else if (dst->ops->family == AF_INET6) {
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if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
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ttl = tun_encap_info->default_ttl;
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else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
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!net->mpls.ip_ttl_propagate)
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ttl = net->mpls.default_ttl;
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else
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ttl = ipv6_hdr(skb)->hop_limit;
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rt6 = (struct rt6_info *)dst;
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} else {
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goto drop;
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}
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/* Verify the destination can hold the packet */
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new_header_size = mpls_encap_size(tun_encap_info);
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mtu = mpls_dev_mtu(out_dev);
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if (mpls_pkt_too_big(skb, mtu - new_header_size))
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goto drop;
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hh_len = LL_RESERVED_SPACE(out_dev);
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if (!out_dev->header_ops)
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hh_len = 0;
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/* Ensure there is enough space for the headers in the skb */
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if (skb_cow(skb, hh_len + new_header_size))
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goto drop;
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skb_set_inner_protocol(skb, skb->protocol);
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skb_reset_inner_network_header(skb);
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skb_push(skb, new_header_size);
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skb_reset_network_header(skb);
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skb->dev = out_dev;
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skb->protocol = htons(ETH_P_MPLS_UC);
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/* Push the new labels */
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hdr = mpls_hdr(skb);
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bos = true;
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for (i = tun_encap_info->labels - 1; i >= 0; i--) {
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hdr[i] = mpls_entry_encode(tun_encap_info->label[i],
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ttl, 0, bos);
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bos = false;
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}
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mpls_stats_inc_outucastpkts(out_dev, skb);
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if (rt)
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err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway,
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skb);
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else if (rt6)
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err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
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skb);
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if (err)
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net_dbg_ratelimited("%s: packet transmission failed: %d\n",
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__func__, err);
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return LWTUNNEL_XMIT_DONE;
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drop:
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out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;
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if (out_mdev)
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MPLS_INC_STATS(out_mdev, tx_errors);
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kfree_skb(skb);
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return -EINVAL;
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}
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static int mpls_build_state(struct nlattr *nla,
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unsigned int family, const void *cfg,
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struct lwtunnel_state **ts,
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struct netlink_ext_ack *extack)
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{
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struct mpls_iptunnel_encap *tun_encap_info;
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struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1];
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struct lwtunnel_state *newts;
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u8 n_labels;
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int ret;
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ret = nla_parse_nested(tb, MPLS_IPTUNNEL_MAX, nla,
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mpls_iptunnel_policy, extack);
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if (ret < 0)
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return ret;
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if (!tb[MPLS_IPTUNNEL_DST]) {
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NL_SET_ERR_MSG(extack, "MPLS_IPTUNNEL_DST attribute is missing");
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return -EINVAL;
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}
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/* determine number of labels */
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if (nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS,
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&n_labels, NULL, extack))
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return -EINVAL;
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newts = lwtunnel_state_alloc(sizeof(*tun_encap_info) +
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n_labels * sizeof(u32));
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if (!newts)
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return -ENOMEM;
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tun_encap_info = mpls_lwtunnel_encap(newts);
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ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], n_labels,
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&tun_encap_info->labels, tun_encap_info->label,
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extack);
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if (ret)
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goto errout;
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tun_encap_info->ttl_propagate = MPLS_TTL_PROP_DEFAULT;
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if (tb[MPLS_IPTUNNEL_TTL]) {
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tun_encap_info->default_ttl = nla_get_u8(tb[MPLS_IPTUNNEL_TTL]);
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/* TTL 0 implies propagate from IP header */
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tun_encap_info->ttl_propagate = tun_encap_info->default_ttl ?
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MPLS_TTL_PROP_DISABLED :
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MPLS_TTL_PROP_ENABLED;
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}
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newts->type = LWTUNNEL_ENCAP_MPLS;
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newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
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newts->headroom = mpls_encap_size(tun_encap_info);
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*ts = newts;
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return 0;
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errout:
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kfree(newts);
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*ts = NULL;
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return ret;
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}
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static int mpls_fill_encap_info(struct sk_buff *skb,
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struct lwtunnel_state *lwtstate)
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{
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struct mpls_iptunnel_encap *tun_encap_info;
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tun_encap_info = mpls_lwtunnel_encap(lwtstate);
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if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels,
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tun_encap_info->label))
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goto nla_put_failure;
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if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT &&
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nla_put_u8(skb, MPLS_IPTUNNEL_TTL, tun_encap_info->default_ttl))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -EMSGSIZE;
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}
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static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate)
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{
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struct mpls_iptunnel_encap *tun_encap_info;
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int nlsize;
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tun_encap_info = mpls_lwtunnel_encap(lwtstate);
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nlsize = nla_total_size(tun_encap_info->labels * 4);
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if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT)
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nlsize += nla_total_size(1);
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return nlsize;
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}
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static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
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{
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struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a);
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struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b);
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int l;
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if (a_hdr->labels != b_hdr->labels ||
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a_hdr->ttl_propagate != b_hdr->ttl_propagate ||
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a_hdr->default_ttl != b_hdr->default_ttl)
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return 1;
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for (l = 0; l < a_hdr->labels; l++)
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if (a_hdr->label[l] != b_hdr->label[l])
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return 1;
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return 0;
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}
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static const struct lwtunnel_encap_ops mpls_iptun_ops = {
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.build_state = mpls_build_state,
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.xmit = mpls_xmit,
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.fill_encap = mpls_fill_encap_info,
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.get_encap_size = mpls_encap_nlsize,
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.cmp_encap = mpls_encap_cmp,
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.owner = THIS_MODULE,
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};
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static int __init mpls_iptunnel_init(void)
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{
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return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
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}
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module_init(mpls_iptunnel_init);
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static void __exit mpls_iptunnel_exit(void)
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{
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lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
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}
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module_exit(mpls_iptunnel_exit);
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MODULE_ALIAS_RTNL_LWT(MPLS);
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MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels");
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MODULE_LICENSE("GPL v2");
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