1 files changed, 305 insertions, 0 deletions
diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
new file mode 100644
index 000000000..ef59e25dc
--- /dev/null
+++ b/net/mpls/mpls_iptunnel.c
@@ -0,0 +1,305 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * mpls tunnels	An implementation mpls tunnels using the light weight tunnel
+ *		infrastructure
+ *
+ * Authors:	Roopa Prabhu, <roopa@cumulusnetworks.com>
+ */
+#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);
+
+	skb_orphan(skb);
+
+	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 = (struct 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 = (struct 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(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");