Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * IP Payload Compression Protocol (IPComp) - RFC3173.
 *
 * Copyright (c) 2003 James Morris <jmorris@intercode.com.au>
 *
 * Todo:
 *   - Tunable compression parameters.
 *   - Compression stats.
 *   - Adaptive compression.
 */
#include <linux/module.h>
#include <linux/err.h>
#include <linux/rtnetlink.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>
#include <net/ipcomp.h>
#include <net/protocol.h>
#include <net/sock.h>
 
static int ipcomp4_err(struct sk_buff *skb, u32 info)
{
<------>struct net *net = dev_net(skb->dev);
<------>__be32 spi;
<------>const struct iphdr *iph = (const struct iphdr *)skb->data;
<------>struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
<------>struct xfrm_state *x;
 
<------>switch (icmp_hdr(skb)->type) {
<------>case ICMP_DEST_UNREACH:
<------><------>if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
<------><------><------>return 0;
<------>case ICMP_REDIRECT:
<------><------>break;
<------>default:
<------><------>return 0;
<------>}
 
<------>spi = htonl(ntohs(ipch->cpi));
<------>x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
<------><------><------>      spi, IPPROTO_COMP, AF_INET);
<------>if (!x)
<------><------>return 0;
 
<------>if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
<------><------>ipv4_update_pmtu(skb, net, info, 0, IPPROTO_COMP);
<------>else
<------><------>ipv4_redirect(skb, net, 0, IPPROTO_COMP);
<------>xfrm_state_put(x);
 
<------>return 0;
}
 
/* We always hold one tunnel user reference to indicate a tunnel */
static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x)
{
<------>struct net *net = xs_net(x);
<------>struct xfrm_state *t;
 
<------>t = xfrm_state_alloc(net);
<------>if (!t)
<------><------>goto out;
 
<------>t->id.proto = IPPROTO_IPIP;
<------>t->id.spi = x->props.saddr.a4;
<------>t->id.daddr.a4 = x->id.daddr.a4;
<------>memcpy(&t->sel, &x->sel, sizeof(t->sel));
<------>t->props.family = AF_INET;
<------>t->props.mode = x->props.mode;
<------>t->props.saddr.a4 = x->props.saddr.a4;
<------>t->props.flags = x->props.flags;
<------>t->props.extra_flags = x->props.extra_flags;
<------>memcpy(&t->mark, &x->mark, sizeof(t->mark));
<------>t->if_id = x->if_id;
 
<------>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;
}
 
/*
 * Must be protected by xfrm_cfg_mutex.  State and tunnel user references are
 * always incremented on success.
 */
static int ipcomp_tunnel_attach(struct xfrm_state *x)
{
<------>struct net *net = xs_net(x);
<------>int err = 0;
<------>struct xfrm_state *t;
<------>u32 mark = x->mark.v & x->mark.m;
 
<------>t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4,
<------><------><------>      x->props.saddr.a4, IPPROTO_IPIP, AF_INET);
<------>if (!t) {
<------><------>t = ipcomp_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 ipcomp4_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 iphdr);
<------><------>break;
<------>default:
<------><------>goto out;
<------>}
 
<------>err = ipcomp_init_state(x);
<------>if (err)
<------><------>goto out;
 
<------>if (x->props.mode == XFRM_MODE_TUNNEL) {
<------><------>err = ipcomp_tunnel_attach(x);
<------><------>if (err)
<------><------><------>goto out;
<------>}
 
<------>err = 0;
out:
<------>return err;
}
 
static int ipcomp4_rcv_cb(struct sk_buff *skb, int err)
{
<------>return 0;
}
 
static const struct xfrm_type ipcomp_type = {
<------>.description	= "IPCOMP4",
<------>.owner		= THIS_MODULE,
<------>.proto	     	= IPPROTO_COMP,
<------>.init_state	= ipcomp4_init_state,
<------>.destructor	= ipcomp_destroy,
<------>.input		= ipcomp_input,
<------>.output		= ipcomp_output
};
 
static struct xfrm4_protocol ipcomp4_protocol = {
<------>.handler	=	xfrm4_rcv,
<------>.input_handler	=	xfrm_input,
<------>.cb_handler	=	ipcomp4_rcv_cb,
<------>.err_handler	=	ipcomp4_err,
<------>.priority	=	0,
};
 
static int __init ipcomp4_init(void)
{
<------>if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
<------><------>pr_info("%s: can't add xfrm type\n", __func__);
<------><------>return -EAGAIN;
<------>}
<------>if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
<------><------>pr_info("%s: can't add protocol\n", __func__);
<------><------>xfrm_unregister_type(&ipcomp_type, AF_INET);
<------><------>return -EAGAIN;
<------>}
<------>return 0;
}
 
static void __exit ipcomp4_fini(void)
{
<------>if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0)
<------><------>pr_info("%s: can't remove protocol\n", __func__);
<------>xfrm_unregister_type(&ipcomp_type, AF_INET);
}
 
module_init(ipcomp4_init);
module_exit(ipcomp4_fini);
 
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173");
MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
 
MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);