// SPDX-License-Identifier: GPL-2.0-or-later
/*
* mpls tunnels An implementation mpls tunnels using the light weight tunnel
* infrastructure
*
* Authors: Roopa Prabhu, <[email protected]>
*/
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/net.h>
#include <linux/module.h>
#include <linux/mpls.h>
#include <linux/vmalloc.h>
#include <net/ip.h>
#include <net/dst.h>
#include <net/lwtunnel.h>
#include <net/netevent.h>
#include <net/netns/generic.h>
#include <net/ip6_fib.h>
#include <net/route.h>
#include <net/mpls_iptunnel.h>
#include <linux/mpls_iptunnel.h>
#include "internal.h"
static const struct nla_policy mpls_iptunnel_policy[MPLS_IPTUNNEL_MAX + 1] = {
[MPLS_IPTUNNEL_DST] = { .len = sizeof(u32) },
[MPLS_IPTUNNEL_TTL] = { .type = NLA_U8 },
};
static unsigned int mpls_encap_size(struct mpls_iptunnel_encap *en)
{
/* The size of the layer 2.5 labels to be added for this route */
return en->labels * sizeof(struct mpls_shim_hdr);
}
static int mpls_xmit(struct sk_buff *skb)
{
struct mpls_iptunnel_encap *tun_encap_info;
struct mpls_shim_hdr *hdr;
struct net_device *out_dev;
unsigned int hh_len;
unsigned int new_header_size;
unsigned int mtu;
struct dst_entry *dst = skb_dst(skb);
struct rtable *rt = NULL;
struct rt6_info *rt6 = NULL;
struct mpls_dev *out_mdev;
struct net *net;
int err = 0;
bool bos;
int i;
unsigned int ttl;
/* Find the output device */
out_dev = dst->dev;
net = dev_net(out_dev);
if (!mpls_output_possible(out_dev) ||
!dst->lwtstate || skb_warn_if_lro(skb))
goto drop;
skb_forward_csum(skb);
tun_encap_info = mpls_lwtunnel_encap(dst->lwtstate);
/* Obtain the ttl using the following set of rules.
*
* LWT ttl propagation setting:
* - disabled => use default TTL value from LWT
* - enabled => use TTL value from IPv4/IPv6 header
* - default =>
* Global ttl propagation setting:
* - disabled => use default TTL value from global setting
* - enabled => use TTL value from IPv4/IPv6 header
*/
if (dst->ops->family == AF_INET) {
if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
ttl = tun_encap_info->default_ttl;
else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
!net->mpls.ip_ttl_propagate)
ttl = net->mpls.default_ttl;
else
ttl = ip_hdr(skb)->ttl;
rt = dst_rtable(dst);
} else if (dst->ops->family == AF_INET6) {
if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DISABLED)
ttl = tun_encap_info->default_ttl;
else if (tun_encap_info->ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
!net->mpls.ip_ttl_propagate)
ttl = net->mpls.default_ttl;
else
ttl = ipv6_hdr(skb)->hop_limit;
rt6 = dst_rt6_info(dst);
} else {
goto drop;
}
/* Verify the destination can hold the packet */
new_header_size = mpls_encap_size(tun_encap_info);
mtu = mpls_dev_mtu(out_dev);
if (mpls_pkt_too_big(skb, mtu - new_header_size))
goto drop;
hh_len = LL_RESERVED_SPACE(out_dev);
if (!out_dev->header_ops)
hh_len = 0;
/* Ensure there is enough space for the headers in the skb */
if (skb_cow_head(skb, hh_len + new_header_size))
goto drop;
skb_set_inner_protocol(skb, skb->protocol);
skb_reset_inner_network_header(skb);
skb_push(skb, new_header_size);
skb_reset_network_header(skb);
skb->dev = out_dev;
skb->protocol = htons(ETH_P_MPLS_UC);
/* Push the new labels */
hdr = mpls_hdr(skb);
bos = true;
for (i = tun_encap_info->labels - 1; i >= 0; i--) {
hdr[i] = mpls_entry_encode(tun_encap_info->label[i],
ttl, 0, bos);
bos = false;
}
mpls_stats_inc_outucastpkts(out_dev, skb);
if (rt) {
if (rt->rt_gw_family == AF_INET6)
err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt->rt_gw6,
skb);
else
err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gw4,
skb);
} else if (rt6) {
if (ipv6_addr_v4mapped(&rt6->rt6i_gateway)) {
/* 6PE (RFC 4798) */
err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt6->rt6i_gateway.s6_addr32[3],
skb);
} else
err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
skb);
}
if (err)
net_dbg_ratelimited("%s: packet transmission failed: %d\n",
__func__, err);
return LWTUNNEL_XMIT_DONE;
drop:
out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;
if (out_mdev)
MPLS_INC_STATS(out_mdev, tx_errors);
kfree_skb(skb);
return -EINVAL;
}
static int mpls_build_state(struct net *net, struct nlattr *nla,
unsigned int family, const void *cfg,
struct lwtunnel_state **ts,
struct netlink_ext_ack *extack)
{
struct mpls_iptunnel_encap *tun_encap_info;
struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1];
struct lwtunnel_state *newts;
u8 n_labels;
int ret;
ret = nla_parse_nested_deprecated(tb, MPLS_IPTUNNEL_MAX, nla,
mpls_iptunnel_policy, extack);
if (ret < 0)
return ret;
if (!tb[MPLS_IPTUNNEL_DST]) {
NL_SET_ERR_MSG(extack, "MPLS_IPTUNNEL_DST attribute is missing");
return -EINVAL;
}
/* determine number of labels */
if (nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS,
&n_labels, NULL, extack))
return -EINVAL;
newts = lwtunnel_state_alloc(struct_size(tun_encap_info, label,
n_labels));
if (!newts)
return -ENOMEM;
tun_encap_info = mpls_lwtunnel_encap(newts);
ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], n_labels,
&tun_encap_info->labels, tun_encap_info->label,
extack);
if (ret)
goto errout;
tun_encap_info->ttl_propagate = MPLS_TTL_PROP_DEFAULT;
if (tb[MPLS_IPTUNNEL_TTL]) {
tun_encap_info->default_ttl = nla_get_u8(tb[MPLS_IPTUNNEL_TTL]);
/* TTL 0 implies propagate from IP header */
tun_encap_info->ttl_propagate = tun_encap_info->default_ttl ?
MPLS_TTL_PROP_DISABLED :
MPLS_TTL_PROP_ENABLED;
}
newts->type = LWTUNNEL_ENCAP_MPLS;
newts->flags |= LWTUNNEL_STATE_XMIT_REDIRECT;
newts->headroom = mpls_encap_size(tun_encap_info);
*ts = newts;
return 0;
errout:
kfree(newts);
*ts = NULL;
return ret;
}
static int mpls_fill_encap_info(struct sk_buff *skb,
struct lwtunnel_state *lwtstate)
{
struct mpls_iptunnel_encap *tun_encap_info;
tun_encap_info = mpls_lwtunnel_encap(lwtstate);
if (nla_put_labels(skb, MPLS_IPTUNNEL_DST, tun_encap_info->labels,
tun_encap_info->label))
goto nla_put_failure;
if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT &&
nla_put_u8(skb, MPLS_IPTUNNEL_TTL, tun_encap_info->default_ttl))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static int mpls_encap_nlsize(struct lwtunnel_state *lwtstate)
{
struct mpls_iptunnel_encap *tun_encap_info;
int nlsize;
tun_encap_info = mpls_lwtunnel_encap(lwtstate);
nlsize = nla_total_size(tun_encap_info->labels * 4);
if (tun_encap_info->ttl_propagate != MPLS_TTL_PROP_DEFAULT)
nlsize += nla_total_size(1);
return nlsize;
}
static int mpls_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
{
struct mpls_iptunnel_encap *a_hdr = mpls_lwtunnel_encap(a);
struct mpls_iptunnel_encap *b_hdr = mpls_lwtunnel_encap(b);
int l;
if (a_hdr->labels != b_hdr->labels ||
a_hdr->ttl_propagate != b_hdr->ttl_propagate ||
a_hdr->default_ttl != b_hdr->default_ttl)
return 1;
for (l = 0; l < a_hdr->labels; l++)
if (a_hdr->label[l] != b_hdr->label[l])
return 1;
return 0;
}
static const struct lwtunnel_encap_ops mpls_iptun_ops = {
.build_state = mpls_build_state,
.xmit = mpls_xmit,
.fill_encap = mpls_fill_encap_info,
.get_encap_size = mpls_encap_nlsize,
.cmp_encap = mpls_encap_cmp,
.owner = THIS_MODULE,
};
static int __init mpls_iptunnel_init(void)
{
return lwtunnel_encap_add_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
}
module_init(mpls_iptunnel_init);
static void __exit mpls_iptunnel_exit(void)
{
lwtunnel_encap_del_ops(&mpls_iptun_ops, LWTUNNEL_ENCAP_MPLS);
}
module_exit(mpls_iptunnel_exit);
MODULE_ALIAS_RTNL_LWT(MPLS);
MODULE_SOFTDEP("post: mpls_gso");
MODULE_DESCRIPTION("MultiProtocol Label Switching IP Tunnels");
MODULE_LICENSE("GPL v2");
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