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200 lines
4.4 KiB
200 lines
4.4 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* IP Payload Compression Protocol (IPComp) - RFC3173. |
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* |
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* Copyright (c) 2003 James Morris <[email protected]> |
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* |
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* Todo: |
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* - Tunable compression parameters. |
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* - Compression stats. |
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* - Adaptive compression. |
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*/ |
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#include <linux/module.h> |
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#include <linux/err.h> |
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#include <linux/rtnetlink.h> |
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#include <net/ip.h> |
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#include <net/xfrm.h> |
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#include <net/icmp.h> |
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#include <net/ipcomp.h> |
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#include <net/protocol.h> |
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#include <net/sock.h> |
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static int ipcomp4_err(struct sk_buff *skb, u32 info) |
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{ |
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struct net *net = dev_net(skb->dev); |
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__be32 spi; |
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const struct iphdr *iph = (const struct iphdr *)skb->data; |
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struct ip_comp_hdr *ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); |
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struct xfrm_state *x; |
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switch (icmp_hdr(skb)->type) { |
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case ICMP_DEST_UNREACH: |
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if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) |
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return 0; |
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break; |
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case ICMP_REDIRECT: |
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break; |
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default: |
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return 0; |
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} |
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spi = htonl(ntohs(ipch->cpi)); |
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x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, |
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spi, IPPROTO_COMP, AF_INET); |
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if (!x) |
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return 0; |
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if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) |
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ipv4_update_pmtu(skb, net, info, 0, IPPROTO_COMP); |
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else |
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ipv4_redirect(skb, net, 0, IPPROTO_COMP); |
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xfrm_state_put(x); |
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return 0; |
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} |
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/* We always hold one tunnel user reference to indicate a tunnel */ |
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static struct xfrm_state *ipcomp_tunnel_create(struct xfrm_state *x) |
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{ |
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struct net *net = xs_net(x); |
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struct xfrm_state *t; |
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t = xfrm_state_alloc(net); |
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if (!t) |
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goto out; |
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t->id.proto = IPPROTO_IPIP; |
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t->id.spi = x->props.saddr.a4; |
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t->id.daddr.a4 = x->id.daddr.a4; |
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memcpy(&t->sel, &x->sel, sizeof(t->sel)); |
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t->props.family = AF_INET; |
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t->props.mode = x->props.mode; |
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t->props.saddr.a4 = x->props.saddr.a4; |
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t->props.flags = x->props.flags; |
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t->props.extra_flags = x->props.extra_flags; |
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memcpy(&t->mark, &x->mark, sizeof(t->mark)); |
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t->if_id = x->if_id; |
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if (xfrm_init_state(t)) |
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goto error; |
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atomic_set(&t->tunnel_users, 1); |
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out: |
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return t; |
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error: |
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t->km.state = XFRM_STATE_DEAD; |
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xfrm_state_put(t); |
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t = NULL; |
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goto out; |
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} |
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/* |
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* Must be protected by xfrm_cfg_mutex. State and tunnel user references are |
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* always incremented on success. |
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*/ |
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static int ipcomp_tunnel_attach(struct xfrm_state *x) |
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{ |
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struct net *net = xs_net(x); |
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int err = 0; |
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struct xfrm_state *t; |
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u32 mark = x->mark.v & x->mark.m; |
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t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr.a4, |
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x->props.saddr.a4, IPPROTO_IPIP, AF_INET); |
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if (!t) { |
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t = ipcomp_tunnel_create(x); |
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if (!t) { |
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err = -EINVAL; |
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goto out; |
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} |
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xfrm_state_insert(t); |
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xfrm_state_hold(t); |
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} |
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x->tunnel = t; |
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atomic_inc(&t->tunnel_users); |
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out: |
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return err; |
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} |
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static int ipcomp4_init_state(struct xfrm_state *x) |
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{ |
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int err = -EINVAL; |
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x->props.header_len = 0; |
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switch (x->props.mode) { |
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case XFRM_MODE_TRANSPORT: |
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break; |
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case XFRM_MODE_TUNNEL: |
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x->props.header_len += sizeof(struct iphdr); |
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break; |
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default: |
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goto out; |
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} |
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err = ipcomp_init_state(x); |
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if (err) |
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goto out; |
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if (x->props.mode == XFRM_MODE_TUNNEL) { |
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err = ipcomp_tunnel_attach(x); |
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if (err) |
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goto out; |
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} |
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err = 0; |
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out: |
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return err; |
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} |
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static int ipcomp4_rcv_cb(struct sk_buff *skb, int err) |
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{ |
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return 0; |
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} |
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static const struct xfrm_type ipcomp_type = { |
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.owner = THIS_MODULE, |
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.proto = IPPROTO_COMP, |
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.init_state = ipcomp4_init_state, |
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.destructor = ipcomp_destroy, |
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.input = ipcomp_input, |
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.output = ipcomp_output |
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}; |
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static struct xfrm4_protocol ipcomp4_protocol = { |
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.handler = xfrm4_rcv, |
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.input_handler = xfrm_input, |
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.cb_handler = ipcomp4_rcv_cb, |
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.err_handler = ipcomp4_err, |
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.priority = 0, |
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}; |
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static int __init ipcomp4_init(void) |
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{ |
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if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) { |
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pr_info("%s: can't add xfrm type\n", __func__); |
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return -EAGAIN; |
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} |
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if (xfrm4_protocol_register(&ipcomp4_protocol, IPPROTO_COMP) < 0) { |
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pr_info("%s: can't add protocol\n", __func__); |
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xfrm_unregister_type(&ipcomp_type, AF_INET); |
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return -EAGAIN; |
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} |
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return 0; |
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} |
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static void __exit ipcomp4_fini(void) |
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{ |
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if (xfrm4_protocol_deregister(&ipcomp4_protocol, IPPROTO_COMP) < 0) |
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pr_info("%s: can't remove protocol\n", __func__); |
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xfrm_unregister_type(&ipcomp_type, AF_INET); |
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} |
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module_init(ipcomp4_init); |
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module_exit(ipcomp4_fini); |
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MODULE_LICENSE("GPL"); |
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MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp/IPv4) - RFC3173"); |
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MODULE_AUTHOR("James Morris <[email protected]>"); |
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MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_COMP);
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