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remarkable-linux/net/netfilter/nfnetlink_cthelper.c
David S. Miller a01aa920b8 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 
Pablo Neira Ayuso says:

====================
Netfilter/IPVS updates for net-next

The following patchset contains Netfilter updates for your net-next
tree. A large bunch of code cleanups, simplify the conntrack extension
codebase, get rid of the fake conntrack object, speed up netns by
selective synchronize_net() calls. More specifically, they are:

1) Check for ct->status bit instead of using nfct_nat() from IPVS and
   Netfilter codebase, patch from Florian Westphal.

2) Use kcalloc() wherever possible in the IPVS code, from Varsha Rao.

3) Simplify FTP IPVS helper module registration path, from Arushi Singhal.

4) Introduce nft_is_base_chain() helper function.

5) Enforce expectation limit from userspace conntrack helper,
   from Gao Feng.

6) Add nf_ct_remove_expect() helper function, from Gao Feng.

7) NAT mangle helper function return boolean, from Gao Feng.

8) ctnetlink_alloc_expect() should only work for conntrack with
   helpers, from Gao Feng.

9) Add nfnl_msg_type() helper function to nfnetlink to build the
   netlink message type.

10) Get rid of unnecessary cast on void, from simran singhal.

11) Use seq_puts()/seq_putc() instead of seq_printf() where possible,
    also from simran singhal.

12) Use list_prev_entry() from nf_tables, from simran signhal.

13) Remove unnecessary & on pointer function in the Netfilter and IPVS
    code.

14) Remove obsolete comment on set of rules per CPU in ip6_tables,
    no longer true. From Arushi Singhal.

15) Remove duplicated nf_conntrack_l4proto_udplite4, from Gao Feng.

16) Remove unnecessary nested rcu_read_lock() in
    __nf_nat_decode_session(). Code running from hooks are already
    guaranteed to run under RCU read side.

17) Remove deadcode in nf_tables_getobj(), from Aaron Conole.

18) Remove double assignment in nf_ct_l4proto_pernet_unregister_one(),
    also from Aaron.

19) Get rid of unsed __ip_set_get_netlink(), from Aaron Conole.

20) Don't propagate NF_DROP error to userspace via ctnetlink in
    __nf_nat_alloc_null_binding() function, from Gao Feng.

21) Revisit nf_ct_deliver_cached_events() to remove unnecessary checks,
    from Gao Feng.

22) Kill the fake untracked conntrack objects, use ctinfo instead to
    annotate a conntrack object is untracked, from Florian Westphal.

23) Remove nf_ct_is_untracked(), now obsolete since we have no
    conntrack template anymore, from Florian.

24) Add event mask support to nft_ct, also from Florian.

25) Move nf_conn_help structure to
    include/net/netfilter/nf_conntrack_helper.h.

26) Add a fixed 32 bytes scratchpad area for conntrack helpers.
    Thus, we don't deal with variable conntrack extensions anymore.
    Make sure userspace conntrack helper doesn't go over that size.
    Remove variable size ct extension infrastructure now this code
    got no more clients. From Florian Westphal.

27) Restore offset and length of nf_ct_ext structure to 8 bytes now
    that wraparound is not possible any longer, also from Florian.

28) Allow to get rid of unassured flows under stress in conntrack,
    this applies to DCCP, SCTP and TCP protocols, from Florian.

29) Shrink size of nf_conntrack_ecache structure, from Florian.

30) Use TCP_MAX_WSCALE instead of hardcoded 14 in TCP tracker,
    from Gao Feng.

31) Register SYNPROXY hooks on demand, from Florian Westphal.

32) Use pernet hook whenever possible, instead of global hook
    registration, from Florian Westphal.

33) Pass hook structure to ebt_register_table() to consolidate some
    infrastructure code, from Florian Westphal.

34) Use consume_skb() and return NF_STOLEN, instead of NF_DROP in the
    SYNPROXY code, to make sure device stats are not fooled, patch
    from Gao Feng.

35) Remove NF_CT_EXT_F_PREALLOC this kills quite some code that we
    don't need anymore if we just select a fixed size instead of
    expensive runtime time calculation of this. From Florian.

36) Constify nf_ct_extend_register() and nf_ct_extend_unregister(),
    from Florian.

37) Simplify nf_ct_ext_add(), this kills nf_ct_ext_create(), from
    Florian.

38) Attach NAT extension on-demand from masquerade and pptp helper
    path, from Florian.

39) Get rid of useless ip_vs_set_state_timeout(), from Aaron Conole.

40) Speed up netns by selective calls of synchronize_net(), from
    Florian Westphal.

41) Silence stack size warning gcc in 32-bit arch in snmp helper,
    from Florian.

42) Inconditionally call nf_ct_ext_destroy(), even if we have no
    extensions, to deal with the NF_NAT_MANIP_SRC case. Patch from
    Liping Zhang.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-01 10:47:53 -04:00

773 lines
19 KiB
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/*
* (C) 2012 Pablo Neira Ayuso <pablo@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 (or any later at your option).
*
* This software has been sponsored by Vyatta Inc. <http://www.vyatta.com>
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/rculist.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <net/netlink.h>
#include <net/sock.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
#include <linux/netfilter/nfnetlink_cthelper.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
struct nfnl_cthelper {
struct list_head list;
struct nf_conntrack_helper helper;
};
static LIST_HEAD(nfnl_cthelper_list);
static int
nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
struct nf_conn *ct, enum ip_conntrack_info ctinfo)
{
const struct nf_conn_help *help;
struct nf_conntrack_helper *helper;
help = nfct_help(ct);
if (help == NULL)
return NF_DROP;
/* rcu_read_lock()ed by nf_hook_thresh */
helper = rcu_dereference(help->helper);
if (helper == NULL)
return NF_DROP;
/* This is a user-space helper not yet configured, skip. */
if ((helper->flags &
(NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
NF_CT_HELPER_F_USERSPACE)
return NF_ACCEPT;
/* If the user-space helper is not available, don't block traffic. */
return NF_QUEUE_NR(helper->queue_num) | NF_VERDICT_FLAG_QUEUE_BYPASS;
}
static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
[NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
[NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
};
static int
nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
const struct nlattr *attr)
{
int err;
struct nlattr *tb[NFCTH_TUPLE_MAX+1];
err = nla_parse_nested(tb, NFCTH_TUPLE_MAX, attr,
nfnl_cthelper_tuple_pol, NULL);
if (err < 0)
return err;
if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
return -EINVAL;
/* Not all fields are initialized so first zero the tuple */
memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
return 0;
}
static int
nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
{
struct nf_conn_help *help = nfct_help(ct);
if (attr == NULL)
return -EINVAL;
if (help->helper->data_len == 0)
return -EINVAL;
nla_memcpy(help->data, nla_data(attr), sizeof(help->data));
return 0;
}
static int
nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
{
const struct nf_conn_help *help = nfct_help(ct);
if (help->helper->data_len &&
nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
goto nla_put_failure;
return 0;
nla_put_failure:
return -ENOSPC;
}
static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
[NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
.len = NF_CT_HELPER_NAME_LEN-1 },
[NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
[NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
};
static int
nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
const struct nlattr *attr)
{
int err;
struct nlattr *tb[NFCTH_POLICY_MAX+1];
err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr,
nfnl_cthelper_expect_pol, NULL);
if (err < 0)
return err;
if (!tb[NFCTH_POLICY_NAME] ||
!tb[NFCTH_POLICY_EXPECT_MAX] ||
!tb[NFCTH_POLICY_EXPECT_TIMEOUT])
return -EINVAL;
strncpy(expect_policy->name,
nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
expect_policy->max_expected =
ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
if (expect_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
return -EINVAL;
expect_policy->timeout =
ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
return 0;
}
static const struct nla_policy
nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
[NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
};
static int
nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
const struct nlattr *attr)
{
int i, ret;
struct nf_conntrack_expect_policy *expect_policy;
struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
unsigned int class_max;
ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
nfnl_cthelper_expect_policy_set, NULL);
if (ret < 0)
return ret;
if (!tb[NFCTH_POLICY_SET_NUM])
return -EINVAL;
class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
if (class_max == 0)
return -EINVAL;
if (class_max > NF_CT_MAX_EXPECT_CLASSES)
return -EOVERFLOW;
expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
class_max, GFP_KERNEL);
if (expect_policy == NULL)
return -ENOMEM;
for (i = 0; i < class_max; i++) {
if (!tb[NFCTH_POLICY_SET+i])
goto err;
ret = nfnl_cthelper_expect_policy(&expect_policy[i],
tb[NFCTH_POLICY_SET+i]);
if (ret < 0)
goto err;
}
helper->expect_class_max = class_max - 1;
helper->expect_policy = expect_policy;
return 0;
err:
kfree(expect_policy);
return -EINVAL;
}
static int
nfnl_cthelper_create(const struct nlattr * const tb[],
struct nf_conntrack_tuple *tuple)
{
struct nf_conntrack_helper *helper;
struct nfnl_cthelper *nfcth;
unsigned int size;
int ret;
if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
return -EINVAL;
nfcth = kzalloc(sizeof(*nfcth), GFP_KERNEL);
if (nfcth == NULL)
return -ENOMEM;
helper = &nfcth->helper;
ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
if (ret < 0)
goto err1;
strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
if (size > FIELD_SIZEOF(struct nf_conn_help, data)) {
ret = -ENOMEM;
goto err2;
}
helper->flags |= NF_CT_HELPER_F_USERSPACE;
memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
helper->me = THIS_MODULE;
helper->help = nfnl_userspace_cthelper;
helper->from_nlattr = nfnl_cthelper_from_nlattr;
helper->to_nlattr = nfnl_cthelper_to_nlattr;
/* Default to queue number zero, this can be updated at any time. */
if (tb[NFCTH_QUEUE_NUM])
helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
if (tb[NFCTH_STATUS]) {
int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
switch(status) {
case NFCT_HELPER_STATUS_ENABLED:
helper->flags |= NF_CT_HELPER_F_CONFIGURED;
break;
case NFCT_HELPER_STATUS_DISABLED:
helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
break;
}
}
ret = nf_conntrack_helper_register(helper);
if (ret < 0)
goto err2;
list_add_tail(&nfcth->list, &nfnl_cthelper_list);
return 0;
err2:
kfree(helper->expect_policy);
err1:
kfree(nfcth);
return ret;
}
static int
nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy,
struct nf_conntrack_expect_policy *new_policy,
const struct nlattr *attr)
{
struct nlattr *tb[NFCTH_POLICY_MAX + 1];
int err;
err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr,
nfnl_cthelper_expect_pol, NULL);
if (err < 0)
return err;
if (!tb[NFCTH_POLICY_NAME] ||
!tb[NFCTH_POLICY_EXPECT_MAX] ||
!tb[NFCTH_POLICY_EXPECT_TIMEOUT])
return -EINVAL;
if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name))
return -EBUSY;
new_policy->max_expected =
ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
if (new_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
return -EINVAL;
new_policy->timeout =
ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
return 0;
}
static int nfnl_cthelper_update_policy_all(struct nlattr *tb[],
struct nf_conntrack_helper *helper)
{
struct nf_conntrack_expect_policy new_policy[helper->expect_class_max + 1];
struct nf_conntrack_expect_policy *policy;
int i, err;
/* Check first that all policy attributes are well-formed, so we don't
* leave things in inconsistent state on errors.
*/
for (i = 0; i < helper->expect_class_max + 1; i++) {
if (!tb[NFCTH_POLICY_SET + i])
return -EINVAL;
err = nfnl_cthelper_update_policy_one(&helper->expect_policy[i],
&new_policy[i],
tb[NFCTH_POLICY_SET + i]);
if (err < 0)
return err;
}
/* Now we can safely update them. */
for (i = 0; i < helper->expect_class_max + 1; i++) {
policy = (struct nf_conntrack_expect_policy *)
&helper->expect_policy[i];
policy->max_expected = new_policy->max_expected;
policy->timeout = new_policy->timeout;
}
return 0;
}
static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper,
const struct nlattr *attr)
{
struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1];
unsigned int class_max;
int err;
err = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
nfnl_cthelper_expect_policy_set, NULL);
if (err < 0)
return err;
if (!tb[NFCTH_POLICY_SET_NUM])
return -EINVAL;
class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
if (helper->expect_class_max + 1 != class_max)
return -EBUSY;
return nfnl_cthelper_update_policy_all(tb, helper);
}
static int
nfnl_cthelper_update(const struct nlattr * const tb[],
struct nf_conntrack_helper *helper)
{
int ret;
if (tb[NFCTH_PRIV_DATA_LEN])
return -EBUSY;
if (tb[NFCTH_POLICY]) {
ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
if (ret < 0)
return ret;
}
if (tb[NFCTH_QUEUE_NUM])
helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
if (tb[NFCTH_STATUS]) {
int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
switch(status) {
case NFCT_HELPER_STATUS_ENABLED:
helper->flags |= NF_CT_HELPER_F_CONFIGURED;
break;
case NFCT_HELPER_STATUS_DISABLED:
helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
break;
}
}
return 0;
}
static int nfnl_cthelper_new(struct net *net, struct sock *nfnl,
struct sk_buff *skb, const struct nlmsghdr *nlh,
const struct nlattr * const tb[])
{
const char *helper_name;
struct nf_conntrack_helper *cur, *helper = NULL;
struct nf_conntrack_tuple tuple;
struct nfnl_cthelper *nlcth;
int ret = 0;
if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
return -EINVAL;
helper_name = nla_data(tb[NFCTH_NAME]);
ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
if (ret < 0)
return ret;
list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
cur = &nlcth->helper;
if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
continue;
if ((tuple.src.l3num != cur->tuple.src.l3num ||
tuple.dst.protonum != cur->tuple.dst.protonum))
continue;
if (nlh->nlmsg_flags & NLM_F_EXCL)
return -EEXIST;
helper = cur;
break;
}
if (helper == NULL)
ret = nfnl_cthelper_create(tb, &tuple);
else
ret = nfnl_cthelper_update(tb, helper);
return ret;
}
static int
nfnl_cthelper_dump_tuple(struct sk_buff *skb,
struct nf_conntrack_helper *helper)
{
struct nlattr *nest_parms;
nest_parms = nla_nest_start(skb, NFCTH_TUPLE | NLA_F_NESTED);
if (nest_parms == NULL)
goto nla_put_failure;
if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
htons(helper->tuple.src.l3num)))
goto nla_put_failure;
if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
goto nla_put_failure;
nla_nest_end(skb, nest_parms);
return 0;
nla_put_failure:
return -1;
}
static int
nfnl_cthelper_dump_policy(struct sk_buff *skb,
struct nf_conntrack_helper *helper)
{
int i;
struct nlattr *nest_parms1, *nest_parms2;
nest_parms1 = nla_nest_start(skb, NFCTH_POLICY | NLA_F_NESTED);
if (nest_parms1 == NULL)
goto nla_put_failure;
if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
htonl(helper->expect_class_max + 1)))
goto nla_put_failure;
for (i = 0; i < helper->expect_class_max + 1; i++) {
nest_parms2 = nla_nest_start(skb,
(NFCTH_POLICY_SET+i) | NLA_F_NESTED);
if (nest_parms2 == NULL)
goto nla_put_failure;
if (nla_put_string(skb, NFCTH_POLICY_NAME,
helper->expect_policy[i].name))
goto nla_put_failure;
if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
htonl(helper->expect_policy[i].max_expected)))
goto nla_put_failure;
if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
htonl(helper->expect_policy[i].timeout)))
goto nla_put_failure;
nla_nest_end(skb, nest_parms2);
}
nla_nest_end(skb, nest_parms1);
return 0;
nla_put_failure:
return -1;
}
static int
nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
int event, struct nf_conntrack_helper *helper)
{
struct nlmsghdr *nlh;
struct nfgenmsg *nfmsg;
unsigned int flags = portid ? NLM_F_MULTI : 0;
int status;
event = nfnl_msg_type(NFNL_SUBSYS_CTHELPER, event);
nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
if (nlh == NULL)
goto nlmsg_failure;
nfmsg = nlmsg_data(nlh);
nfmsg->nfgen_family = AF_UNSPEC;
nfmsg->version = NFNETLINK_V0;
nfmsg->res_id = 0;
if (nla_put_string(skb, NFCTH_NAME, helper->name))
goto nla_put_failure;
if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
goto nla_put_failure;
if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
goto nla_put_failure;
if (nfnl_cthelper_dump_policy(skb, helper) < 0)
goto nla_put_failure;
if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
goto nla_put_failure;
if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
status = NFCT_HELPER_STATUS_ENABLED;
else
status = NFCT_HELPER_STATUS_DISABLED;
if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
goto nla_put_failure;
nlmsg_end(skb, nlh);
return skb->len;
nlmsg_failure:
nla_put_failure:
nlmsg_cancel(skb, nlh);
return -1;
}
static int
nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
{
struct nf_conntrack_helper *cur, *last;
rcu_read_lock();
last = (struct nf_conntrack_helper *)cb->args[1];
for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
restart:
hlist_for_each_entry_rcu(cur,
&nf_ct_helper_hash[cb->args[0]], hnode) {
/* skip non-userspace conntrack helpers. */
if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
continue;
if (cb->args[1]) {
if (cur != last)
continue;
cb->args[1] = 0;
}
if (nfnl_cthelper_fill_info(skb,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
NFNL_MSG_CTHELPER_NEW, cur) < 0) {
cb->args[1] = (unsigned long)cur;
goto out;
}
}
}
if (cb->args[1]) {
cb->args[1] = 0;
goto restart;
}
out:
rcu_read_unlock();
return skb->len;
}
static int nfnl_cthelper_get(struct net *net, struct sock *nfnl,
struct sk_buff *skb, const struct nlmsghdr *nlh,
const struct nlattr * const tb[])
{
int ret = -ENOENT;
struct nf_conntrack_helper *cur;
struct sk_buff *skb2;
char *helper_name = NULL;
struct nf_conntrack_tuple tuple;
struct nfnl_cthelper *nlcth;
bool tuple_set = false;
if (nlh->nlmsg_flags & NLM_F_DUMP) {
struct netlink_dump_control c = {
.dump = nfnl_cthelper_dump_table,
};
return netlink_dump_start(nfnl, skb, nlh, &c);
}
if (tb[NFCTH_NAME])
helper_name = nla_data(tb[NFCTH_NAME]);
if (tb[NFCTH_TUPLE]) {
ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
if (ret < 0)
return ret;
tuple_set = true;
}
list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
cur = &nlcth->helper;
if (helper_name &&
strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
continue;
if (tuple_set &&
(tuple.src.l3num != cur->tuple.src.l3num ||
tuple.dst.protonum != cur->tuple.dst.protonum))
continue;
skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (skb2 == NULL) {
ret = -ENOMEM;
break;
}
ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
nlh->nlmsg_seq,
NFNL_MSG_TYPE(nlh->nlmsg_type),
NFNL_MSG_CTHELPER_NEW, cur);
if (ret <= 0) {
kfree_skb(skb2);
break;
}
ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
MSG_DONTWAIT);
if (ret > 0)
ret = 0;
/* this avoids a loop in nfnetlink. */
return ret == -EAGAIN ? -ENOBUFS : ret;
}
return ret;
}
static int nfnl_cthelper_del(struct net *net, struct sock *nfnl,
struct sk_buff *skb, const struct nlmsghdr *nlh,
const struct nlattr * const tb[])
{
char *helper_name = NULL;
struct nf_conntrack_helper *cur;
struct nf_conntrack_tuple tuple;
bool tuple_set = false, found = false;
struct nfnl_cthelper *nlcth, *n;
int j = 0, ret;
if (tb[NFCTH_NAME])
helper_name = nla_data(tb[NFCTH_NAME]);
if (tb[NFCTH_TUPLE]) {
ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
if (ret < 0)
return ret;
tuple_set = true;
}
list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
cur = &nlcth->helper;
j++;
if (helper_name &&
strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
continue;
if (tuple_set &&
(tuple.src.l3num != cur->tuple.src.l3num ||
tuple.dst.protonum != cur->tuple.dst.protonum))
continue;
found = true;
nf_conntrack_helper_unregister(cur);
kfree(cur->expect_policy);
list_del(&nlcth->list);
kfree(nlcth);
}
/* Make sure we return success if we flush and there is no helpers */
return (found || j == 0) ? 0 : -ENOENT;
}
static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
[NFCTH_NAME] = { .type = NLA_NUL_STRING,
.len = NF_CT_HELPER_NAME_LEN-1 },
[NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
};
static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
[NFNL_MSG_CTHELPER_NEW] = { .call = nfnl_cthelper_new,
.attr_count = NFCTH_MAX,
.policy = nfnl_cthelper_policy },
[NFNL_MSG_CTHELPER_GET] = { .call = nfnl_cthelper_get,
.attr_count = NFCTH_MAX,
.policy = nfnl_cthelper_policy },
[NFNL_MSG_CTHELPER_DEL] = { .call = nfnl_cthelper_del,
.attr_count = NFCTH_MAX,
.policy = nfnl_cthelper_policy },
};
static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
.name = "cthelper",
.subsys_id = NFNL_SUBSYS_CTHELPER,
.cb_count = NFNL_MSG_CTHELPER_MAX,
.cb = nfnl_cthelper_cb,
};
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
static int __init nfnl_cthelper_init(void)
{
int ret;
ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
if (ret < 0) {
pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
goto err_out;
}
return 0;
err_out:
return ret;
}
static void __exit nfnl_cthelper_exit(void)
{
struct nf_conntrack_helper *cur;
struct nfnl_cthelper *nlcth, *n;
nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
cur = &nlcth->helper;
nf_conntrack_helper_unregister(cur);
kfree(cur->expect_policy);
kfree(nlcth);
}
}
module_init(nfnl_cthelper_init);
module_exit(nfnl_cthelper_exit);
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