// SPDX-License-Identifier: GPL-2.0-or-later/* * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173 * * Copyright (C)2003 USAGI/WIDE Project * * Author	Mitsuru KANDA  <mk@linux-ipv6.org> *//* * [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 lock_class_key xfrm_state_lock_key;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;	lockdep_set_class(&t->lock, &xfrm_state_lock_key); 	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));	t->if_id = x->if_id; 	if (xfrm_init_state(t, NULL))		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,			      struct netlink_ext_ack *extack){	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:		NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp");		goto out;	} 	err = ipcomp_init_state(x, extack);	if (err)		goto out; 	if (x->props.mode == XFRM_MODE_TUNNEL) {		err = ipcomp6_tunnel_attach(x);		if (err) {			NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state");			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 = {	.owner		= THIS_MODULE,	.proto		= IPPROTO_COMP,	.init_state	= ipcomp6_init_state,	.destructor	= ipcomp_destroy,	.input		= ipcomp_input,	.output		= ipcomp_output,}; static struct xfrm6_protocol ipcomp6_protocol = {	.handler	= xfrm6_rcv,	.input_handler	= xfrm_input,	.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__);	xfrm_unregister_type(&ipcomp6_type, AF_INET6);} 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);