diff options
Diffstat (limited to 'net/ipv4/ipcomp.c')
| -rw-r--r-- | net/ipv4/ipcomp.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c new file mode 100644 index 000000000..5a4fb2539 --- /dev/null +++ b/net/ipv4/ipcomp.c @@ -0,0 +1,204 @@ +// 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; + break; + 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, + 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 iphdr); + 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 = ipcomp_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 ipcomp4_rcv_cb(struct sk_buff *skb, int err) +{ + return 0; +} + +static const struct xfrm_type ipcomp_type = { + .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); |