1 files changed, 405 insertions, 0 deletions
diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
new file mode 100644
index 0000000000..1323f2f692
--- /dev/null
+++ b/net/ipv6/xfrm6_tunnel.c
@@ -0,0 +1,405 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C)2003,2004 USAGI/WIDE Project
+ *
+ * Authors	Mitsuru KANDA  <mk@linux-ipv6.org>
+ *		YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
+ *
+ * Based on net/ipv4/xfrm4_tunnel.c
+ */
+#include <linux/module.h>
+#include <linux/xfrm.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+#include <net/ipv6.h>
+#include <linux/ipv6.h>
+#include <linux/icmpv6.h>
+#include <linux/mutex.h>
+#include <net/netns/generic.h>
+
+#define XFRM6_TUNNEL_SPI_BYADDR_HSIZE 256
+#define XFRM6_TUNNEL_SPI_BYSPI_HSIZE 256
+
+#define XFRM6_TUNNEL_SPI_MIN	1
+#define XFRM6_TUNNEL_SPI_MAX	0xffffffff
+
+struct xfrm6_tunnel_net {
+	struct hlist_head spi_byaddr[XFRM6_TUNNEL_SPI_BYADDR_HSIZE];
+	struct hlist_head spi_byspi[XFRM6_TUNNEL_SPI_BYSPI_HSIZE];
+	u32 spi;
+};
+
+static unsigned int xfrm6_tunnel_net_id __read_mostly;
+static inline struct xfrm6_tunnel_net *xfrm6_tunnel_pernet(struct net *net)
+{
+	return net_generic(net, xfrm6_tunnel_net_id);
+}
+
+/*
+ * xfrm_tunnel_spi things are for allocating unique id ("spi")
+ * per xfrm_address_t.
+ */
+struct xfrm6_tunnel_spi {
+	struct hlist_node	list_byaddr;
+	struct hlist_node	list_byspi;
+	xfrm_address_t		addr;
+	u32			spi;
+	refcount_t		refcnt;
+	struct rcu_head		rcu_head;
+};
+
+static DEFINE_SPINLOCK(xfrm6_tunnel_spi_lock);
+
+static struct kmem_cache *xfrm6_tunnel_spi_kmem __read_mostly;
+
+static inline unsigned int xfrm6_tunnel_spi_hash_byaddr(const xfrm_address_t *addr)
+{
+	unsigned int h;
+
+	h = ipv6_addr_hash((const struct in6_addr *)addr);
+	h ^= h >> 16;
+	h ^= h >> 8;
+	h &= XFRM6_TUNNEL_SPI_BYADDR_HSIZE - 1;
+
+	return h;
+}
+
+static inline unsigned int xfrm6_tunnel_spi_hash_byspi(u32 spi)
+{
+	return spi % XFRM6_TUNNEL_SPI_BYSPI_HSIZE;
+}
+
+static struct xfrm6_tunnel_spi *__xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
+{
+	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
+	struct xfrm6_tunnel_spi *x6spi;
+
+	hlist_for_each_entry_rcu(x6spi,
+			     &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
+			     list_byaddr, lockdep_is_held(&xfrm6_tunnel_spi_lock)) {
+		if (xfrm6_addr_equal(&x6spi->addr, saddr))
+			return x6spi;
+	}
+
+	return NULL;
+}
+
+__be32 xfrm6_tunnel_spi_lookup(struct net *net, const xfrm_address_t *saddr)
+{
+	struct xfrm6_tunnel_spi *x6spi;
+	u32 spi;
+
+	rcu_read_lock_bh();
+	x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
+	spi = x6spi ? x6spi->spi : 0;
+	rcu_read_unlock_bh();
+	return htonl(spi);
+}
+EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
+
+static int __xfrm6_tunnel_spi_check(struct net *net, u32 spi)
+{
+	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
+	struct xfrm6_tunnel_spi *x6spi;
+	int index = xfrm6_tunnel_spi_hash_byspi(spi);
+
+	hlist_for_each_entry(x6spi,
+			     &xfrm6_tn->spi_byspi[index],
+			     list_byspi) {
+		if (x6spi->spi == spi)
+			return -1;
+	}
+	return index;
+}
+
+static u32 __xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
+{
+	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
+	u32 spi;
+	struct xfrm6_tunnel_spi *x6spi;
+	int index;
+
+	if (xfrm6_tn->spi < XFRM6_TUNNEL_SPI_MIN ||
+	    xfrm6_tn->spi >= XFRM6_TUNNEL_SPI_MAX)
+		xfrm6_tn->spi = XFRM6_TUNNEL_SPI_MIN;
+	else
+		xfrm6_tn->spi++;
+
+	for (spi = xfrm6_tn->spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
+		index = __xfrm6_tunnel_spi_check(net, spi);
+		if (index >= 0)
+			goto alloc_spi;
+
+		if (spi == XFRM6_TUNNEL_SPI_MAX)
+			break;
+	}
+	for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tn->spi; spi++) {
+		index = __xfrm6_tunnel_spi_check(net, spi);
+		if (index >= 0)
+			goto alloc_spi;
+	}
+	spi = 0;
+	goto out;
+alloc_spi:
+	xfrm6_tn->spi = spi;
+	x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
+	if (!x6spi)
+		goto out;
+
+	memcpy(&x6spi->addr, saddr, sizeof(x6spi->addr));
+	x6spi->spi = spi;
+	refcount_set(&x6spi->refcnt, 1);
+
+	hlist_add_head_rcu(&x6spi->list_byspi, &xfrm6_tn->spi_byspi[index]);
+
+	index = xfrm6_tunnel_spi_hash_byaddr(saddr);
+	hlist_add_head_rcu(&x6spi->list_byaddr, &xfrm6_tn->spi_byaddr[index]);
+out:
+	return spi;
+}
+
+__be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
+{
+	struct xfrm6_tunnel_spi *x6spi;
+	u32 spi;
+
+	spin_lock_bh(&xfrm6_tunnel_spi_lock);
+	x6spi = __xfrm6_tunnel_spi_lookup(net, saddr);
+	if (x6spi) {
+		refcount_inc(&x6spi->refcnt);
+		spi = x6spi->spi;
+	} else
+		spi = __xfrm6_tunnel_alloc_spi(net, saddr);
+	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
+
+	return htonl(spi);
+}
+EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);
+
+static void x6spi_destroy_rcu(struct rcu_head *head)
+{
+	kmem_cache_free(xfrm6_tunnel_spi_kmem,
+			container_of(head, struct xfrm6_tunnel_spi, rcu_head));
+}
+
+static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
+{
+	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
+	struct xfrm6_tunnel_spi *x6spi;
+	struct hlist_node *n;
+
+	spin_lock_bh(&xfrm6_tunnel_spi_lock);
+
+	hlist_for_each_entry_safe(x6spi, n,
+				  &xfrm6_tn->spi_byaddr[xfrm6_tunnel_spi_hash_byaddr(saddr)],
+				  list_byaddr)
+	{
+		if (xfrm6_addr_equal(&x6spi->addr, saddr)) {
+			if (refcount_dec_and_test(&x6spi->refcnt)) {
+				hlist_del_rcu(&x6spi->list_byaddr);
+				hlist_del_rcu(&x6spi->list_byspi);
+				call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
+				break;
+			}
+		}
+	}
+	spin_unlock_bh(&xfrm6_tunnel_spi_lock);
+}
+
+static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	skb_push(skb, -skb_network_offset(skb));
+	return 0;
+}
+
+static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+	return skb_network_header(skb)[IP6CB(skb)->nhoff];
+}
+
+static int xfrm6_tunnel_rcv(struct sk_buff *skb)
+{
+	struct net *net = dev_net(skb->dev);
+	const struct ipv6hdr *iph = ipv6_hdr(skb);
+	__be32 spi;
+
+	spi = xfrm6_tunnel_spi_lookup(net, (const xfrm_address_t *)&iph->saddr);
+	return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi, NULL);
+}
+
+static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+			    u8 type, u8 code, int offset, __be32 info)
+{
+	/* xfrm6_tunnel native err handling */
+	switch (type) {
+	case ICMPV6_DEST_UNREACH:
+		switch (code) {
+		case ICMPV6_NOROUTE:
+		case ICMPV6_ADM_PROHIBITED:
+		case ICMPV6_NOT_NEIGHBOUR:
+		case ICMPV6_ADDR_UNREACH:
+		case ICMPV6_PORT_UNREACH:
+		default:
+			break;
+		}
+		break;
+	case ICMPV6_PKT_TOOBIG:
+		break;
+	case ICMPV6_TIME_EXCEED:
+		switch (code) {
+		case ICMPV6_EXC_HOPLIMIT:
+			break;
+		case ICMPV6_EXC_FRAGTIME:
+		default:
+			break;
+		}
+		break;
+	case ICMPV6_PARAMPROB:
+		switch (code) {
+		case ICMPV6_HDR_FIELD: break;
+		case ICMPV6_UNK_NEXTHDR: break;
+		case ICMPV6_UNK_OPTION: break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int xfrm6_tunnel_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
+{
+	if (x->props.mode != XFRM_MODE_TUNNEL) {
+		NL_SET_ERR_MSG(extack, "IPv6 tunnel can only be used with tunnel mode");
+		return -EINVAL;
+	}
+
+	if (x->encap) {
+		NL_SET_ERR_MSG(extack, "IPv6 tunnel is not compatible with encapsulation");
+		return -EINVAL;
+	}
+
+	x->props.header_len = sizeof(struct ipv6hdr);
+
+	return 0;
+}
+
+static void xfrm6_tunnel_destroy(struct xfrm_state *x)
+{
+	struct net *net = xs_net(x);
+
+	xfrm6_tunnel_free_spi(net, (xfrm_address_t *)&x->props.saddr);
+}
+
+static const struct xfrm_type xfrm6_tunnel_type = {
+	.owner          = THIS_MODULE,
+	.proto		= IPPROTO_IPV6,
+	.init_state	= xfrm6_tunnel_init_state,
+	.destructor	= xfrm6_tunnel_destroy,
+	.input		= xfrm6_tunnel_input,
+	.output		= xfrm6_tunnel_output,
+};
+
+static struct xfrm6_tunnel xfrm6_tunnel_handler __read_mostly = {
+	.handler	= xfrm6_tunnel_rcv,
+	.err_handler	= xfrm6_tunnel_err,
+	.priority	= 3,
+};
+
+static struct xfrm6_tunnel xfrm46_tunnel_handler __read_mostly = {
+	.handler	= xfrm6_tunnel_rcv,
+	.err_handler	= xfrm6_tunnel_err,
+	.priority	= 3,
+};
+
+static int __net_init xfrm6_tunnel_net_init(struct net *net)
+{
+	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
+	unsigned int i;
+
+	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
+		INIT_HLIST_HEAD(&xfrm6_tn->spi_byaddr[i]);
+	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
+		INIT_HLIST_HEAD(&xfrm6_tn->spi_byspi[i]);
+	xfrm6_tn->spi = 0;
+
+	return 0;
+}
+
+static void __net_exit xfrm6_tunnel_net_exit(struct net *net)
+{
+	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
+	unsigned int i;
+
+	xfrm_flush_gc();
+	xfrm_state_flush(net, 0, false, true);
+
+	for (i = 0; i < XFRM6_TUNNEL_SPI_BYADDR_HSIZE; i++)
+		WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byaddr[i]));
+
+	for (i = 0; i < XFRM6_TUNNEL_SPI_BYSPI_HSIZE; i++)
+		WARN_ON_ONCE(!hlist_empty(&xfrm6_tn->spi_byspi[i]));
+}
+
+static struct pernet_operations xfrm6_tunnel_net_ops = {
+	.init	= xfrm6_tunnel_net_init,
+	.exit	= xfrm6_tunnel_net_exit,
+	.id	= &xfrm6_tunnel_net_id,
+	.size	= sizeof(struct xfrm6_tunnel_net),
+};
+
+static int __init xfrm6_tunnel_init(void)
+{
+	int rv;
+
+	xfrm6_tunnel_spi_kmem = kmem_cache_create("xfrm6_tunnel_spi",
+						  sizeof(struct xfrm6_tunnel_spi),
+						  0, SLAB_HWCACHE_ALIGN,
+						  NULL);
+	if (!xfrm6_tunnel_spi_kmem)
+		return -ENOMEM;
+	rv = register_pernet_subsys(&xfrm6_tunnel_net_ops);
+	if (rv < 0)
+		goto out_pernet;
+	rv = xfrm_register_type(&xfrm6_tunnel_type, AF_INET6);
+	if (rv < 0)
+		goto out_type;
+	rv = xfrm6_tunnel_register(&xfrm6_tunnel_handler, AF_INET6);
+	if (rv < 0)
+		goto out_xfrm6;
+	rv = xfrm6_tunnel_register(&xfrm46_tunnel_handler, AF_INET);
+	if (rv < 0)
+		goto out_xfrm46;
+	return 0;
+
+out_xfrm46:
+	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
+out_xfrm6:
+	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
+out_type:
+	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
+out_pernet:
+	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
+	return rv;
+}
+
+static void __exit xfrm6_tunnel_fini(void)
+{
+	xfrm6_tunnel_deregister(&xfrm46_tunnel_handler, AF_INET);
+	xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
+	xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
+	unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
+	/* Someone maybe has gotten the xfrm6_tunnel_spi.
+	 * So need to wait it.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
+}
+
+module_init(xfrm6_tunnel_init);
+module_exit(xfrm6_tunnel_fini);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_IPV6);