nf_conntrack_proto_udplite.c
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
* (C) 2007 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/module.h>
#include <linux/udp.h>
#include <linux/seq_file.h>
#include <linux/skbuff.h>
#include <linux/ipv6.h>
#include <net/ip6_checksum.h>
#include <net/checksum.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_log.h>
enum udplite_conntrack {
UDPLITE_CT_UNREPLIED,
UDPLITE_CT_REPLIED,
UDPLITE_CT_MAX
};
static unsigned int udplite_timeouts[UDPLITE_CT_MAX] = {
[UDPLITE_CT_UNREPLIED] = 30*HZ,
[UDPLITE_CT_REPLIED] = 180*HZ,
};
static int udplite_net_id __read_mostly;
struct udplite_net {
struct nf_proto_net pn;
unsigned int timeouts[UDPLITE_CT_MAX];
};
static inline struct udplite_net *udplite_pernet(struct net *net)
{
return net_generic(net, udplite_net_id);
}
static bool udplite_pkt_to_tuple(const struct sk_buff *skb,
unsigned int dataoff,
struct nf_conntrack_tuple *tuple)
{
const struct udphdr *hp;
struct udphdr _hdr;
hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
if (hp == NULL)
return false;
tuple->src.u.udp.port = hp->source;
tuple->dst.u.udp.port = hp->dest;
return true;
}
static bool udplite_invert_tuple(struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_tuple *orig)
{
tuple->src.u.udp.port = orig->dst.u.udp.port;
tuple->dst.u.udp.port = orig->src.u.udp.port;
return true;
}
/* Print out the per-protocol part of the tuple. */
static int udplite_print_tuple(struct seq_file *s,
const struct nf_conntrack_tuple *tuple)
{
return seq_printf(s, "sport=%hu dport=%hu ",
ntohs(tuple->src.u.udp.port),
ntohs(tuple->dst.u.udp.port));
}
static unsigned int *udplite_get_timeouts(struct net *net)
{
return udplite_pernet(net)->timeouts;
}
/* Returns verdict for packet, and may modify conntracktype */
static int udplite_packet(struct nf_conn *ct,
const struct sk_buff *skb,
unsigned int dataoff,
enum ip_conntrack_info ctinfo,
u_int8_t pf,
unsigned int hooknum,
unsigned int *timeouts)
{
/* If we've seen traffic both ways, this is some kind of UDP
stream. Extend timeout. */
if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
nf_ct_refresh_acct(ct, ctinfo, skb,
timeouts[UDPLITE_CT_REPLIED]);
/* Also, more likely to be important, and not a probe */
if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
nf_conntrack_event_cache(IPCT_ASSURED, ct);
} else {
nf_ct_refresh_acct(ct, ctinfo, skb,
timeouts[UDPLITE_CT_UNREPLIED]);
}
return NF_ACCEPT;
}
/* Called when a new connection for this protocol found. */
static bool udplite_new(struct nf_conn *ct, const struct sk_buff *skb,
unsigned int dataoff, unsigned int *timeouts)
{
return true;
}
static int udplite_error(struct net *net, struct nf_conn *tmpl,
struct sk_buff *skb,
unsigned int dataoff,
enum ip_conntrack_info *ctinfo,
u_int8_t pf,
unsigned int hooknum)
{
unsigned int udplen = skb->len - dataoff;
const struct udphdr *hdr;
struct udphdr _hdr;
unsigned int cscov;
/* Header is too small? */
hdr = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
if (hdr == NULL) {
if (LOG_INVALID(net, IPPROTO_UDPLITE))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_udplite: short packet ");
return -NF_ACCEPT;
}
cscov = ntohs(hdr->len);
if (cscov == 0)
cscov = udplen;
else if (cscov < sizeof(*hdr) || cscov > udplen) {
if (LOG_INVALID(net, IPPROTO_UDPLITE))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_udplite: invalid checksum coverage ");
return -NF_ACCEPT;
}
/* UDPLITE mandates checksums */
if (!hdr->check) {
if (LOG_INVALID(net, IPPROTO_UDPLITE))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_udplite: checksum missing ");
return -NF_ACCEPT;
}
/* Checksum invalid? Ignore. */
if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_UDP,
pf)) {
if (LOG_INVALID(net, IPPROTO_UDPLITE))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_udplite: bad UDPLite checksum ");
return -NF_ACCEPT;
}
return NF_ACCEPT;
}
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_cttimeout.h>
static int udplite_timeout_nlattr_to_obj(struct nlattr *tb[],
struct net *net, void *data)
{
unsigned int *timeouts = data;
struct udplite_net *un = udplite_pernet(net);
/* set default timeouts for UDPlite. */
timeouts[UDPLITE_CT_UNREPLIED] = un->timeouts[UDPLITE_CT_UNREPLIED];
timeouts[UDPLITE_CT_REPLIED] = un->timeouts[UDPLITE_CT_REPLIED];
if (tb[CTA_TIMEOUT_UDPLITE_UNREPLIED]) {
timeouts[UDPLITE_CT_UNREPLIED] =
ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_UNREPLIED])) * HZ;
}
if (tb[CTA_TIMEOUT_UDPLITE_REPLIED]) {
timeouts[UDPLITE_CT_REPLIED] =
ntohl(nla_get_be32(tb[CTA_TIMEOUT_UDPLITE_REPLIED])) * HZ;
}
return 0;
}
static int
udplite_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
{
const unsigned int *timeouts = data;
if (nla_put_be32(skb, CTA_TIMEOUT_UDPLITE_UNREPLIED,
htonl(timeouts[UDPLITE_CT_UNREPLIED] / HZ)) ||
nla_put_be32(skb, CTA_TIMEOUT_UDPLITE_REPLIED,
htonl(timeouts[UDPLITE_CT_REPLIED] / HZ)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -ENOSPC;
}
static const struct nla_policy
udplite_timeout_nla_policy[CTA_TIMEOUT_UDPLITE_MAX+1] = {
[CTA_TIMEOUT_UDPLITE_UNREPLIED] = { .type = NLA_U32 },
[CTA_TIMEOUT_UDPLITE_REPLIED] = { .type = NLA_U32 },
};
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
#ifdef CONFIG_SYSCTL
static struct ctl_table udplite_sysctl_table[] = {
{
.procname = "nf_conntrack_udplite_timeout",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_udplite_timeout_stream",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{ }
};
#endif /* CONFIG_SYSCTL */
static int udplite_kmemdup_sysctl_table(struct nf_proto_net *pn,
struct udplite_net *un)
{
#ifdef CONFIG_SYSCTL
if (pn->ctl_table)
return 0;
pn->ctl_table = kmemdup(udplite_sysctl_table,
sizeof(udplite_sysctl_table),
GFP_KERNEL);
if (!pn->ctl_table)
return -ENOMEM;
pn->ctl_table[0].data = &un->timeouts[UDPLITE_CT_UNREPLIED];
pn->ctl_table[1].data = &un->timeouts[UDPLITE_CT_REPLIED];
#endif
return 0;
}
static int udplite_init_net(struct net *net, u_int16_t proto)
{
struct udplite_net *un = udplite_pernet(net);
struct nf_proto_net *pn = &un->pn;
if (!pn->users) {
int i;
for (i = 0 ; i < UDPLITE_CT_MAX; i++)
un->timeouts[i] = udplite_timeouts[i];
}
return udplite_kmemdup_sysctl_table(pn, un);
}
static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite4 __read_mostly =
{
.l3proto = PF_INET,
.l4proto = IPPROTO_UDPLITE,
.name = "udplite",
.pkt_to_tuple = udplite_pkt_to_tuple,
.invert_tuple = udplite_invert_tuple,
.print_tuple = udplite_print_tuple,
.packet = udplite_packet,
.get_timeouts = udplite_get_timeouts,
.new = udplite_new,
.error = udplite_error,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nla_policy = nf_ct_port_nla_policy,
#endif
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
.ctnl_timeout = {
.nlattr_to_obj = udplite_timeout_nlattr_to_obj,
.obj_to_nlattr = udplite_timeout_obj_to_nlattr,
.nlattr_max = CTA_TIMEOUT_UDPLITE_MAX,
.obj_size = sizeof(unsigned int) *
CTA_TIMEOUT_UDPLITE_MAX,
.nla_policy = udplite_timeout_nla_policy,
},
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
.net_id = &udplite_net_id,
.init_net = udplite_init_net,
};
static struct nf_conntrack_l4proto nf_conntrack_l4proto_udplite6 __read_mostly =
{
.l3proto = PF_INET6,
.l4proto = IPPROTO_UDPLITE,
.name = "udplite",
.pkt_to_tuple = udplite_pkt_to_tuple,
.invert_tuple = udplite_invert_tuple,
.print_tuple = udplite_print_tuple,
.packet = udplite_packet,
.get_timeouts = udplite_get_timeouts,
.new = udplite_new,
.error = udplite_error,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nla_policy = nf_ct_port_nla_policy,
#endif
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
.ctnl_timeout = {
.nlattr_to_obj = udplite_timeout_nlattr_to_obj,
.obj_to_nlattr = udplite_timeout_obj_to_nlattr,
.nlattr_max = CTA_TIMEOUT_UDPLITE_MAX,
.obj_size = sizeof(unsigned int) *
CTA_TIMEOUT_UDPLITE_MAX,
.nla_policy = udplite_timeout_nla_policy,
},
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
.net_id = &udplite_net_id,
.init_net = udplite_init_net,
};
static int udplite_net_init(struct net *net)
{
int ret = 0;
ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udplite4);
if (ret < 0) {
pr_err("nf_conntrack_udplite4: pernet registration failed.\n");
goto out;
}
ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udplite6);
if (ret < 0) {
pr_err("nf_conntrack_udplite6: pernet registration failed.\n");
goto cleanup_udplite4;
}
return 0;
cleanup_udplite4:
nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udplite4);
out:
return ret;
}
static void udplite_net_exit(struct net *net)
{
nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udplite6);
nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udplite4);
}
static struct pernet_operations udplite_net_ops = {
.init = udplite_net_init,
.exit = udplite_net_exit,
.id = &udplite_net_id,
.size = sizeof(struct udplite_net),
};
static int __init nf_conntrack_proto_udplite_init(void)
{
int ret;
ret = register_pernet_subsys(&udplite_net_ops);
if (ret < 0)
goto out_pernet;
ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udplite4);
if (ret < 0)
goto out_udplite4;
ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udplite6);
if (ret < 0)
goto out_udplite6;
return 0;
out_udplite6:
nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
out_udplite4:
unregister_pernet_subsys(&udplite_net_ops);
out_pernet:
return ret;
}
static void __exit nf_conntrack_proto_udplite_exit(void)
{
nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udplite6);
nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udplite4);
unregister_pernet_subsys(&udplite_net_ops);
}
module_init(nf_conntrack_proto_udplite_init);
module_exit(nf_conntrack_proto_udplite_exit);
MODULE_LICENSE("GPL");