v4.19.13 snapshot.
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
new file mode 100644
index 0000000..54d165b
--- /dev/null
+++ b/net/ipv6/ipcomp6.c
@@ -0,0 +1,231 @@
+/*
+ * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
+ *
+ * Copyright (C)2003 USAGI/WIDE Project
+ *
+ * Author Mitsuru KANDA <mk@linux-ipv6.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+/*
+ * [Memo]
+ *
+ * Outbound:
+ * The compression of IP datagram MUST be done before AH/ESP processing,
+ * fragmentation, and the addition of Hop-by-Hop/Routing header.
+ *
+ * Inbound:
+ * The decompression of IP datagram MUST be done after the reassembly,
+ * AH/ESP processing.
+ */
+
+#define pr_fmt(fmt) "IPv6: " fmt
+
+#include <linux/module.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+#include <net/ipcomp.h>
+#include <linux/crypto.h>
+#include <linux/err.h>
+#include <linux/pfkeyv2.h>
+#include <linux/random.h>
+#include <linux/percpu.h>
+#include <linux/smp.h>
+#include <linux/list.h>
+#include <linux/vmalloc.h>
+#include <linux/rtnetlink.h>
+#include <net/ip6_route.h>
+#include <net/icmp.h>
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <linux/ipv6.h>
+#include <linux/icmpv6.h>
+#include <linux/mutex.h>
+
+static int ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+ u8 type, u8 code, int offset, __be32 info)
+{
+ struct net *net = dev_net(skb->dev);
+ __be32 spi;
+ const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
+ struct ip_comp_hdr *ipcomph =
+ (struct ip_comp_hdr *)(skb->data + offset);
+ struct xfrm_state *x;
+
+ if (type != ICMPV6_PKT_TOOBIG &&
+ type != NDISC_REDIRECT)
+ return 0;
+
+ spi = htonl(ntohs(ipcomph->cpi));
+ x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
+ spi, IPPROTO_COMP, AF_INET6);
+ if (!x)
+ return 0;
+
+ if (type == NDISC_REDIRECT)
+ ip6_redirect(skb, net, skb->dev->ifindex, 0,
+ sock_net_uid(net, NULL));
+ else
+ ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
+ xfrm_state_put(x);
+
+ return 0;
+}
+
+static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
+{
+ struct net *net = xs_net(x);
+ struct xfrm_state *t = NULL;
+
+ t = xfrm_state_alloc(net);
+ if (!t)
+ goto out;
+
+ t->id.proto = IPPROTO_IPV6;
+ t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr);
+ if (!t->id.spi)
+ goto error;
+
+ memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
+ memcpy(&t->sel, &x->sel, sizeof(t->sel));
+ t->props.family = AF_INET6;
+ t->props.mode = x->props.mode;
+ memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
+ memcpy(&t->mark, &x->mark, sizeof(t->mark));
+
+ if (xfrm_init_state(t))
+ goto error;
+
+ atomic_set(&t->tunnel_users, 1);
+
+out:
+ return t;
+
+error:
+ t->km.state = XFRM_STATE_DEAD;
+ xfrm_state_put(t);
+ t = NULL;
+ goto out;
+}
+
+static int ipcomp6_tunnel_attach(struct xfrm_state *x)
+{
+ struct net *net = xs_net(x);
+ int err = 0;
+ struct xfrm_state *t = NULL;
+ __be32 spi;
+ u32 mark = x->mark.m & x->mark.v;
+
+ spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr);
+ if (spi)
+ t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr,
+ spi, IPPROTO_IPV6, AF_INET6);
+ if (!t) {
+ t = ipcomp6_tunnel_create(x);
+ if (!t) {
+ err = -EINVAL;
+ goto out;
+ }
+ xfrm_state_insert(t);
+ xfrm_state_hold(t);
+ }
+ x->tunnel = t;
+ atomic_inc(&t->tunnel_users);
+
+out:
+ return err;
+}
+
+static int ipcomp6_init_state(struct xfrm_state *x)
+{
+ int err = -EINVAL;
+
+ x->props.header_len = 0;
+ switch (x->props.mode) {
+ case XFRM_MODE_TRANSPORT:
+ break;
+ case XFRM_MODE_TUNNEL:
+ x->props.header_len += sizeof(struct ipv6hdr);
+ break;
+ default:
+ goto out;
+ }
+
+ err = ipcomp_init_state(x);
+ if (err)
+ goto out;
+
+ if (x->props.mode == XFRM_MODE_TUNNEL) {
+ err = ipcomp6_tunnel_attach(x);
+ if (err)
+ goto out;
+ }
+
+ err = 0;
+out:
+ return err;
+}
+
+static int ipcomp6_rcv_cb(struct sk_buff *skb, int err)
+{
+ return 0;
+}
+
+static const struct xfrm_type ipcomp6_type = {
+ .description = "IPCOMP6",
+ .owner = THIS_MODULE,
+ .proto = IPPROTO_COMP,
+ .init_state = ipcomp6_init_state,
+ .destructor = ipcomp_destroy,
+ .input = ipcomp_input,
+ .output = ipcomp_output,
+ .hdr_offset = xfrm6_find_1stfragopt,
+};
+
+static struct xfrm6_protocol ipcomp6_protocol = {
+ .handler = xfrm6_rcv,
+ .cb_handler = ipcomp6_rcv_cb,
+ .err_handler = ipcomp6_err,
+ .priority = 0,
+};
+
+static int __init ipcomp6_init(void)
+{
+ if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
+ pr_info("%s: can't add xfrm type\n", __func__);
+ return -EAGAIN;
+ }
+ if (xfrm6_protocol_register(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
+ pr_info("%s: can't add protocol\n", __func__);
+ xfrm_unregister_type(&ipcomp6_type, AF_INET6);
+ return -EAGAIN;
+ }
+ return 0;
+}
+
+static void __exit ipcomp6_fini(void)
+{
+ if (xfrm6_protocol_deregister(&ipcomp6_protocol, IPPROTO_COMP) < 0)
+ pr_info("%s: can't remove protocol\n", __func__);
+ if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
+ pr_info("%s: can't remove xfrm type\n", __func__);
+}
+
+module_init(ipcomp6_init);
+module_exit(ipcomp6_fini);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
+MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
+
+MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);