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305 lines
7.8 KiB
305 lines
7.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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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, <[email protected]> |
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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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if (rt->rt_gw_family == AF_INET6) |
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err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt->rt_gw6, |
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skb); |
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else |
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err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gw4, |
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skb); |
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} else if (rt6) { |
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if (ipv6_addr_v4mapped(&rt6->rt6i_gateway)) { |
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/* 6PE (RFC 4798) */ |
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err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt6->rt6i_gateway.s6_addr32[3], |
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skb); |
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} else |
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err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway, |
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skb); |
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} |
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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 net *net, 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_deprecated(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(struct_size(tun_encap_info, label, |
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n_labels)); |
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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_SOFTDEP("post: mpls_gso"); |
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MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels"); |
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MODULE_LICENSE("GPL v2");
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