1 files changed, 387 insertions, 0 deletions

diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
new file mode 100644
index 000000000..e85b5f57d
--- /dev/null
+++ b/net/ipv4/xfrm4_policy.c
@@ -0,0 +1,387 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * xfrm4_policy.c
+ *
+ * Changes:
+ *	Kazunori MIYAZAWA @USAGI
+ * 	YOSHIFUJI Hideaki @USAGI
+ *		Split up af-specific portion
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/inetdevice.h>
+#include <linux/if_tunnel.h>
+#include <net/dst.h>
+#include <net/xfrm.h>
+#include <net/ip.h>
+#include <net/l3mdev.h>
+#include <net/inet_ecn.h>
+
+static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4,
+					    int tos, int oif,
+					    const xfrm_address_t *saddr,
+					    const xfrm_address_t *daddr,
+					    u32 mark)
+{
+	struct rtable *rt;
+
+	memset(fl4, 0, sizeof(*fl4));
+	fl4->daddr = daddr->a4;
+	fl4->flowi4_tos = tos;
+	fl4->flowi4_oif = l3mdev_master_ifindex_by_index(net, oif);
+	fl4->flowi4_mark = mark;
+	if (saddr)
+		fl4->saddr = saddr->a4;
+
+	fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF;
+
+	rt = __ip_route_output_key(net, fl4);
+	if (!IS_ERR(rt))
+		return &rt->dst;
+
+	return ERR_CAST(rt);
+}
+
+static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif,
+					  const xfrm_address_t *saddr,
+					  const xfrm_address_t *daddr,
+					  u32 mark)
+{
+	struct flowi4 fl4;
+
+	return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr, mark);
+}
+
+static int xfrm4_get_saddr(struct net *net, int oif,
+			   xfrm_address_t *saddr, xfrm_address_t *daddr,
+			   u32 mark)
+{
+	struct dst_entry *dst;
+	struct flowi4 fl4;
+
+	dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr, mark);
+	if (IS_ERR(dst))
+		return -EHOSTUNREACH;
+
+	saddr->a4 = fl4.saddr;
+	dst_release(dst);
+	return 0;
+}
+
+static int xfrm4_get_tos(const struct flowi *fl)
+{
+	return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos; /* Strip ECN bits */
+}
+
+static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst,
+			   int nfheader_len)
+{
+	return 0;
+}
+
+static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
+			  const struct flowi *fl)
+{
+	struct rtable *rt = (struct rtable *)xdst->route;
+	const struct flowi4 *fl4 = &fl->u.ip4;
+
+	xdst->u.rt.rt_iif = fl4->flowi4_iif;
+
+	xdst->u.dst.dev = dev;
+	dev_hold(dev);
+
+	/* Sheit... I remember I did this right. Apparently,
+	 * it was magically lost, so this code needs audit */
+	xdst->u.rt.rt_is_input = rt->rt_is_input;
+	xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
+					      RTCF_LOCAL);
+	xdst->u.rt.rt_type = rt->rt_type;
+	xdst->u.rt.rt_gateway = rt->rt_gateway;
+	xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
+	xdst->u.rt.rt_pmtu = rt->rt_pmtu;
+	xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
+	INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
+	rt_add_uncached_list(&xdst->u.rt);
+
+	return 0;
+}
+
+static void
+_decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	int ihl = iph->ihl;
+	u8 *xprth = skb_network_header(skb) + ihl * 4;
+	struct flowi4 *fl4 = &fl->u.ip4;
+	int oif = 0;
+
+	if (skb_dst(skb))
+		oif = skb_dst(skb)->dev->ifindex;
+
+	memset(fl4, 0, sizeof(struct flowi4));
+	fl4->flowi4_mark = skb->mark;
+	fl4->flowi4_oif = reverse ? skb->skb_iif : oif;
+
+	fl4->flowi4_proto = iph->protocol;
+	fl4->daddr = reverse ? iph->saddr : iph->daddr;
+	fl4->saddr = reverse ? iph->daddr : iph->saddr;
+	fl4->flowi4_tos = iph->tos & ~INET_ECN_MASK;
+
+	if (!ip_is_fragment(iph)) {
+		switch (iph->protocol) {
+		case IPPROTO_UDP:
+		case IPPROTO_UDPLITE:
+		case IPPROTO_TCP:
+		case IPPROTO_SCTP:
+		case IPPROTO_DCCP:
+			if (xprth + 4 < skb->data ||
+			    pskb_may_pull(skb, xprth + 4 - skb->data)) {
+				__be16 *ports;
+
+				xprth = skb_network_header(skb) + ihl * 4;
+				ports = (__be16 *)xprth;
+
+				fl4->fl4_sport = ports[!!reverse];
+				fl4->fl4_dport = ports[!reverse];
+			}
+			break;
+
+		case IPPROTO_ICMP:
+			if (xprth + 2 < skb->data ||
+			    pskb_may_pull(skb, xprth + 2 - skb->data)) {
+				u8 *icmp;
+
+				xprth = skb_network_header(skb) + ihl * 4;
+				icmp = xprth;
+
+				fl4->fl4_icmp_type = icmp[0];
+				fl4->fl4_icmp_code = icmp[1];
+			}
+			break;
+
+		case IPPROTO_ESP:
+			if (xprth + 4 < skb->data ||
+			    pskb_may_pull(skb, xprth + 4 - skb->data)) {
+				__be32 *ehdr;
+
+				xprth = skb_network_header(skb) + ihl * 4;
+				ehdr = (__be32 *)xprth;
+
+				fl4->fl4_ipsec_spi = ehdr[0];
+			}
+			break;
+
+		case IPPROTO_AH:
+			if (xprth + 8 < skb->data ||
+			    pskb_may_pull(skb, xprth + 8 - skb->data)) {
+				__be32 *ah_hdr;
+
+				xprth = skb_network_header(skb) + ihl * 4;
+				ah_hdr = (__be32 *)xprth;
+
+				fl4->fl4_ipsec_spi = ah_hdr[1];
+			}
+			break;
+
+		case IPPROTO_COMP:
+			if (xprth + 4 < skb->data ||
+			    pskb_may_pull(skb, xprth + 4 - skb->data)) {
+				__be16 *ipcomp_hdr;
+
+				xprth = skb_network_header(skb) + ihl * 4;
+				ipcomp_hdr = (__be16 *)xprth;
+
+				fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
+			}
+			break;
+
+		case IPPROTO_GRE:
+			if (xprth + 12 < skb->data ||
+			    pskb_may_pull(skb, xprth + 12 - skb->data)) {
+				__be16 *greflags;
+				__be32 *gre_hdr;
+
+				xprth = skb_network_header(skb) + ihl * 4;
+				greflags = (__be16 *)xprth;
+				gre_hdr = (__be32 *)xprth;
+
+				if (greflags[0] & GRE_KEY) {
+					if (greflags[0] & GRE_CSUM)
+						gre_hdr++;
+					fl4->fl4_gre_key = gre_hdr[1];
+				}
+			}
+			break;
+
+		default:
+			fl4->fl4_ipsec_spi = 0;
+			break;
+		}
+	}
+}
+
+static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
+			      struct sk_buff *skb, u32 mtu,
+			      bool confirm_neigh)
+{
+	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
+	struct dst_entry *path = xdst->route;
+
+	path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
+}
+
+static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
+			   struct sk_buff *skb)
+{
+	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
+	struct dst_entry *path = xdst->route;
+
+	path->ops->redirect(path, sk, skb);
+}
+
+static void xfrm4_dst_destroy(struct dst_entry *dst)
+{
+	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
+
+	dst_destroy_metrics_generic(dst);
+	if (xdst->u.rt.rt_uncached_list)
+		rt_del_uncached_list(&xdst->u.rt);
+	xfrm_dst_destroy(xdst);
+}
+
+static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
+			     int unregister)
+{
+	if (!unregister)
+		return;
+
+	xfrm_dst_ifdown(dst, dev);
+}
+
+static struct dst_ops xfrm4_dst_ops_template = {
+	.family =		AF_INET,
+	.update_pmtu =		xfrm4_update_pmtu,
+	.redirect =		xfrm4_redirect,
+	.cow_metrics =		dst_cow_metrics_generic,
+	.destroy =		xfrm4_dst_destroy,
+	.ifdown =		xfrm4_dst_ifdown,
+	.local_out =		__ip_local_out,
+	.gc_thresh =		32768,
+};
+
+static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
+	.dst_ops =		&xfrm4_dst_ops_template,
+	.dst_lookup =		xfrm4_dst_lookup,
+	.get_saddr =		xfrm4_get_saddr,
+	.decode_session =	_decode_session4,
+	.get_tos =		xfrm4_get_tos,
+	.init_path =		xfrm4_init_path,
+	.fill_dst =		xfrm4_fill_dst,
+	.blackhole_route =	ipv4_blackhole_route,
+};
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table xfrm4_policy_table[] = {
+	{
+		.procname       = "xfrm4_gc_thresh",
+		.data           = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
+		.maxlen         = sizeof(int),
+		.mode           = 0644,
+		.proc_handler   = proc_dointvec,
+	},
+	{ }
+};
+
+static __net_init int xfrm4_net_sysctl_init(struct net *net)
+{
+	struct ctl_table *table;
+	struct ctl_table_header *hdr;
+
+	table = xfrm4_policy_table;
+	if (!net_eq(net, &init_net)) {
+		table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
+		if (!table)
+			goto err_alloc;
+
+		table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
+	}
+
+	hdr = register_net_sysctl(net, "net/ipv4", table);
+	if (!hdr)
+		goto err_reg;
+
+	net->ipv4.xfrm4_hdr = hdr;
+	return 0;
+
+err_reg:
+	if (!net_eq(net, &init_net))
+		kfree(table);
+err_alloc:
+	return -ENOMEM;
+}
+
+static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
+{
+	struct ctl_table *table;
+
+	if (!net->ipv4.xfrm4_hdr)
+		return;
+
+	table = net->ipv4.xfrm4_hdr->ctl_table_arg;
+	unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
+	if (!net_eq(net, &init_net))
+		kfree(table);
+}
+#else /* CONFIG_SYSCTL */
+static inline int xfrm4_net_sysctl_init(struct net *net)
+{
+	return 0;
+}
+
+static inline void xfrm4_net_sysctl_exit(struct net *net)
+{
+}
+#endif
+
+static int __net_init xfrm4_net_init(struct net *net)
+{
+	int ret;
+
+	memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
+	       sizeof(xfrm4_dst_ops_template));
+	ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
+	if (ret)
+		return ret;
+
+	ret = xfrm4_net_sysctl_init(net);
+	if (ret)
+		dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
+
+	return ret;
+}
+
+static void __net_exit xfrm4_net_exit(struct net *net)
+{
+	xfrm4_net_sysctl_exit(net);
+	dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
+}
+
+static struct pernet_operations __net_initdata xfrm4_net_ops = {
+	.init	= xfrm4_net_init,
+	.exit	= xfrm4_net_exit,
+};
+
+static void __init xfrm4_policy_init(void)
+{
+	xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
+}
+
+void __init xfrm4_init(void)
+{
+	xfrm4_state_init();
+	xfrm4_policy_init();
+	xfrm4_protocol_init();
+	register_pernet_subsys(&xfrm4_net_ops);
+}