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netfilter: conntrack: remove get_l4proto indirection from l3 protocol trackers 

Handle it in the core instead.

ipv6_skip_exthdr() is built-in even if ipv6 is a module, i.e. this
doesn't create an ipv6 dependency.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2018-06-29 07:46:47 +02:00 committed by Pablo Neira Ayuso
parent d1b6fe9494
commit 6816d931ca
7 changed files with 94 additions and 134 deletions
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8
include/net/netfilter/nf_conntrack_l3proto.h
View File

@ -24,14 +24,6 @@ struct nf_conntrack_l3proto {
/* size of tuple nlattr, fills a hole */
u16 nla_size;
/*
* Called before tracking.
* *dataoff: offset of protocol header (TCP, UDP,...) in skb
* *protonum: protocol number
*/
int (*get_l4proto)(const struct sk_buff *skb, unsigned int nhoff,
unsigned int *dataoff, u_int8_t *protonum);
/* Called when netns wants to use connection tracking */
int (*net_ns_get)(struct net *);
void (*net_ns_put)(struct net *);

30
net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
View File

@ -38,35 +38,6 @@ struct conntrack4_net {
unsigned int users;
};
static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
unsigned int *dataoff, u_int8_t *protonum)
{
const struct iphdr *iph;
struct iphdr _iph;
iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
if (iph == NULL)
return -NF_ACCEPT;
/* Conntrack defragments packets, we might still see fragments
* inside ICMP packets though. */
if (iph->frag_off & htons(IP_OFFSET))
return -NF_ACCEPT;
*dataoff = nhoff + (iph->ihl << 2);
*protonum = iph->protocol;
/* Check bogus IP headers */
if (*dataoff > skb->len) {
pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: "
"nhoff %u, ihl %u, skblen %u\n",
nhoff, iph->ihl << 2, skb->len);
return -NF_ACCEPT;
}
return NF_ACCEPT;
}
static unsigned int ipv4_helper(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
@ -297,7 +268,6 @@ static void ipv4_hooks_unregister(struct net *net)
const struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
.l3proto = PF_INET,
.get_l4proto = ipv4_get_l4proto,
.net_ns_get = ipv4_hooks_register,
.net_ns_put = ipv4_hooks_unregister,
.me = THIS_MODULE,

29
net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c
View File

@ -41,34 +41,6 @@ struct conntrack6_net {
unsigned int users;
};
static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
unsigned int *dataoff, u_int8_t *protonum)
{
unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
__be16 frag_off;
int protoff;
u8 nexthdr;
if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
&nexthdr, sizeof(nexthdr)) != 0) {
pr_debug("ip6_conntrack_core: can't get nexthdr\n");
return -NF_ACCEPT;
}
protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
/*
* (protoff == skb->len) means the packet has not data, just
* IPv6 and possibly extensions headers, but it is tracked anyway
*/
if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
pr_debug("ip6_conntrack_core: can't find proto in pkt\n");
return -NF_ACCEPT;
}
*dataoff = protoff;
*protonum = nexthdr;
return NF_ACCEPT;
}
static unsigned int ipv6_helper(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
@ -281,7 +253,6 @@ static void ipv6_hooks_unregister(struct net *net)
const struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 = {
.l3proto = PF_INET6,
.get_l4proto = ipv6_get_l4proto,
.net_ns_get = ipv6_hooks_register,
.net_ns_put = ipv6_hooks_unregister,
.me = THIS_MODULE,

2
net/netfilter/Makefile
View File

@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
netfilter-objs := core.o nf_log.o nf_queue.o nf_sockopt.o utils.o
nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_proto.o nf_conntrack_l3proto_generic.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o nf_conntrack_extend.o nf_conntrack_acct.o nf_conntrack_seqadj.o
nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_proto.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o nf_conntrack_extend.o nf_conntrack_acct.o nf_conntrack_seqadj.o
nf_conntrack-$(CONFIG_NF_CONNTRACK_TIMEOUT) += nf_conntrack_timeout.o
nf_conntrack-$(CONFIG_NF_CONNTRACK_TIMESTAMP) += nf_conntrack_timestamp.o
nf_conntrack-$(CONFIG_NF_CONNTRACK_EVENTS) += nf_conntrack_ecache.o

108
net/netfilter/nf_conntrack_core.c
View File

@ -37,7 +37,6 @@
#include <linux/rculist_nulls.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_helper.h>
@ -55,6 +54,7 @@
#include <net/netfilter/nf_nat_core.h>
#include <net/netfilter/nf_nat_helper.h>
#include <net/netns/hash.h>
#include <net/ip.h>
#include "nf_internals.h"
@ -273,21 +273,94 @@ nf_ct_get_tuple(const struct sk_buff *skb,
return l4proto->pkt_to_tuple(skb, dataoff, net, tuple);
}
static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
u_int8_t *protonum)
{
int dataoff = -1;
#if IS_ENABLED(CONFIG_NF_CONNTRACK_IPV4)
const struct iphdr *iph;
struct iphdr _iph;
iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
if (!iph)
return -1;
/* Conntrack defragments packets, we might still see fragments
* inside ICMP packets though.
*/
if (iph->frag_off & htons(IP_OFFSET))
return -1;
dataoff = nhoff + (iph->ihl << 2);
*protonum = iph->protocol;
/* Check bogus IP headers */
if (dataoff > skb->len) {
pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
nhoff, iph->ihl << 2, skb->len);
return -1;
}
#endif
return dataoff;
}
static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
u8 *protonum)
{
int protoff = -1;
#if IS_ENABLED(CONFIG_NF_CONNTRACK_IPV6)
unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
__be16 frag_off;
u8 nexthdr;
if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
&nexthdr, sizeof(nexthdr)) != 0) {
pr_debug("can't get nexthdr\n");
return -1;
}
protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
/*
* (protoff == skb->len) means the packet has not data, just
* IPv6 and possibly extensions headers, but it is tracked anyway
*/
if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
pr_debug("can't find proto in pkt\n");
return -1;
}
*protonum = nexthdr;
#endif
return protoff;
}
static int get_l4proto(const struct sk_buff *skb,
unsigned int nhoff, u8 pf, u8 *l4num)
{
switch (pf) {
case NFPROTO_IPV4:
return ipv4_get_l4proto(skb, nhoff, l4num);
case NFPROTO_IPV6:
return ipv6_get_l4proto(skb, nhoff, l4num);
default:
*l4num = 0;
break;
}
return -1;
}
bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
u_int16_t l3num,
struct net *net, struct nf_conntrack_tuple *tuple)
{
const struct nf_conntrack_l3proto *l3proto;
const struct nf_conntrack_l4proto *l4proto;
unsigned int protoff;
u_int8_t protonum;
u8 protonum;
int protoff;
int ret;
rcu_read_lock();
l3proto = __nf_ct_l3proto_find(l3num);
ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
if (ret != NF_ACCEPT) {
protoff = get_l4proto(skb, nhoff, l3num, &protonum);
if (protoff <= 0) {
rcu_read_unlock();
return false;
}
@ -1397,14 +1470,12 @@ unsigned int
nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
struct sk_buff *skb)
{
const struct nf_conntrack_l3proto *l3proto;
const struct nf_conntrack_l4proto *l4proto;
struct nf_conn *ct, *tmpl;
enum ip_conntrack_info ctinfo;
unsigned int *timeouts;
unsigned int dataoff;
u_int8_t protonum;
int ret;
int dataoff, ret;
tmpl = nf_ct_get(skb, &ctinfo);
if (tmpl || ctinfo == IP_CT_UNTRACKED) {
@ -1418,14 +1489,12 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
}
/* rcu_read_lock()ed by nf_hook_thresh */
l3proto = __nf_ct_l3proto_find(pf);
ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
&dataoff, &protonum);
if (ret <= 0) {
dataoff = get_l4proto(skb, skb_network_offset(skb), pf, &protonum);
if (dataoff <= 0) {
pr_debug("not prepared to track yet or error occurred\n");
NF_CT_STAT_INC_ATOMIC(net, error);
NF_CT_STAT_INC_ATOMIC(net, invalid);
ret = -ret;
ret = NF_ACCEPT;
goto out;
}
@ -1641,14 +1710,14 @@ static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
{
const struct nf_conntrack_l3proto *l3proto;
const struct nf_conntrack_l4proto *l4proto;
struct nf_conntrack_tuple_hash *h;
struct nf_conntrack_tuple tuple;
enum ip_conntrack_info ctinfo;
struct nf_nat_hook *nat_hook;
unsigned int dataoff, status;
unsigned int status;
struct nf_conn *ct;
int dataoff;
u16 l3num;
u8 l4num;
@ -1657,10 +1726,9 @@ static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
return 0;
l3num = nf_ct_l3num(ct);
l3proto = nf_ct_l3proto_find_get(l3num);
if (l3proto->get_l4proto(skb, skb_network_offset(skb), &dataoff,
&l4num) <= 0)
dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
if (dataoff <= 0)
return -1;
l4proto = nf_ct_l4proto_find_get(l3num, l4num);

46
net/netfilter/nf_conntrack_l3proto_generic.c
View File

@ -1,46 +0,0 @@
/*
* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
*
* Based largely upon the original ip_conntrack code which
* had the following copyright information:
*
* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
*
* 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.
*
* Author:
* Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
*/
#include <linux/types.h>
#include <linux/ip.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmp.h>
#include <linux/sysctl.h>
#include <net/ip.h>
#include <linux/netfilter_ipv4.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
static int generic_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
unsigned int *dataoff, u_int8_t *protonum)
{
/* Never track !!! */
return -NF_ACCEPT;
}
struct nf_conntrack_l3proto nf_conntrack_l3proto_generic __read_mostly = {
.l3proto = PF_UNSPEC,
.get_l4proto = generic_get_l4proto,
};
EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_generic);

5
net/netfilter/nf_conntrack_proto.c
View File

@ -35,6 +35,11 @@ EXPORT_SYMBOL_GPL(nf_ct_l3protos);
static DEFINE_MUTEX(nf_ct_proto_mutex);
struct nf_conntrack_l3proto nf_conntrack_l3proto_generic __read_mostly = {
.l3proto = PF_UNSPEC,
};
EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_generic);
#ifdef CONFIG_SYSCTL
static int
nf_ct_register_sysctl(struct net *net,