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netfilter: xt_CT: refactorize xt_ct_tg_check
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This patch adds xt_ct_set_helper and xt_ct_set_timeout to reduce
the size of xt_ct_tg_check.

This aims to improve code mantainability by splitting xt_ct_tg_check
in smaller chunks.

Suggested by Eric Dumazet.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Pablo Neira Ayuso committed Sep 3, 2012
1 parent 6703aa7 commit 236df00
Showing 1 changed file with 126 additions and 136 deletions.
262 changes: 126 additions & 136 deletions net/netfilter/xt_CT.c
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Original file line number Diff line number Diff line change
Expand Up @@ -72,14 +72,44 @@ static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
return 0;
}

static int
xt_ct_set_helper(struct nf_conn *ct, const char *helper_name,
const struct xt_tgchk_param *par)
{
struct nf_conntrack_helper *helper;
struct nf_conn_help *help;
u8 proto;

proto = xt_ct_find_proto(par);
if (!proto) {
pr_info("You must specify a L4 protocol, and not use "
"inversions on it.\n");
return -ENOENT;
}

helper = nf_conntrack_helper_try_module_get(helper_name, par->family,
proto);
if (helper == NULL) {
pr_info("No such helper \"%s\"\n", helper_name);
return -ENOENT;
}

help = nf_ct_helper_ext_add(ct, helper, GFP_KERNEL);
if (help == NULL) {
module_put(helper->me);
return -ENOMEM;
}

help->helper = helper;
return 0;
}

static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
{
struct xt_ct_target_info *info = par->targinfo;
struct nf_conntrack_tuple t;
struct nf_conn_help *help;
struct nf_conn *ct;
int ret = 0;
u8 proto;
int ret;

if (info->flags & ~XT_CT_NOTRACK)
return -EINVAL;
Expand Down Expand Up @@ -112,31 +142,9 @@ static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
goto err3;

if (info->helper[0]) {
struct nf_conntrack_helper *helper;

ret = -ENOENT;
proto = xt_ct_find_proto(par);
if (!proto) {
pr_info("You must specify a L4 protocol, "
"and not use inversions on it.\n");
goto err3;
}

ret = -ENOENT;
helper = nf_conntrack_helper_try_module_get(info->helper,
par->family,
proto);
if (helper == NULL) {
pr_info("No such helper \"%s\"\n", info->helper);
goto err3;
}

ret = -ENOMEM;
help = nf_ct_helper_ext_add(ct, helper, GFP_KERNEL);
if (help == NULL)
ret = xt_ct_set_helper(ct, info->helper, par);
if (ret < 0)
goto err3;

help->helper = helper;
}

__set_bit(IPS_TEMPLATE_BIT, &ct->status);
Expand Down Expand Up @@ -164,17 +172,77 @@ static void __xt_ct_tg_timeout_put(struct ctnl_timeout *timeout)
}
#endif

static int
xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par,
const char *timeout_name)
{
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
typeof(nf_ct_timeout_find_get_hook) timeout_find_get;
struct ctnl_timeout *timeout;
struct nf_conn_timeout *timeout_ext;
const struct ipt_entry *e = par->entryinfo;
struct nf_conntrack_l4proto *l4proto;
int ret = 0;

rcu_read_lock();
timeout_find_get = rcu_dereference(nf_ct_timeout_find_get_hook);
if (timeout_find_get == NULL) {
ret = -ENOENT;
pr_info("Timeout policy base is empty\n");
goto out;
}

if (e->ip.invflags & IPT_INV_PROTO) {
ret = -EINVAL;
pr_info("You cannot use inversion on L4 protocol\n");
goto out;
}

timeout = timeout_find_get(timeout_name);
if (timeout == NULL) {
ret = -ENOENT;
pr_info("No such timeout policy \"%s\"\n", timeout_name);
goto out;
}

if (timeout->l3num != par->family) {
ret = -EINVAL;
pr_info("Timeout policy `%s' can only be used by L3 protocol "
"number %d\n", timeout_name, timeout->l3num);
goto err_put_timeout;
}
/* Make sure the timeout policy matches any existing protocol tracker,
* otherwise default to generic.
*/
l4proto = __nf_ct_l4proto_find(par->family, e->ip.proto);
if (timeout->l4proto->l4proto != l4proto->l4proto) {
ret = -EINVAL;
pr_info("Timeout policy `%s' can only be used by L4 protocol "
"number %d\n",
timeout_name, timeout->l4proto->l4proto);
goto err_put_timeout;
}
timeout_ext = nf_ct_timeout_ext_add(ct, timeout, GFP_ATOMIC);
if (timeout_ext == NULL)
ret = -ENOMEM;

err_put_timeout:
__xt_ct_tg_timeout_put(timeout);
out:
rcu_read_unlock();
return ret;
#else
return -EOPNOTSUPP;
#endif
}

static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
{
struct xt_ct_target_info_v1 *info = par->targinfo;
struct nf_conntrack_tuple t;
struct nf_conn_help *help;
struct nf_conn *ct;
int ret = 0;
u8 proto;
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
struct ctnl_timeout *timeout;
#endif
int ret;

if (info->flags & ~XT_CT_NOTRACK)
return -EINVAL;

Expand Down Expand Up @@ -206,106 +274,23 @@ static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
goto err3;

if (info->helper[0]) {
struct nf_conntrack_helper *helper;

ret = -ENOENT;
proto = xt_ct_find_proto(par);
if (!proto) {
pr_info("You must specify a L4 protocol, "
"and not use inversions on it.\n");
goto err3;
}

ret = -ENOENT;
helper = nf_conntrack_helper_try_module_get(info->helper,
par->family,
proto);
if (helper == NULL) {
pr_info("No such helper \"%s\"\n", info->helper);
goto err3;
}

ret = -ENOMEM;
help = nf_ct_helper_ext_add(ct, helper, GFP_KERNEL);
if (help == NULL)
ret = xt_ct_set_helper(ct, info->helper, par);
if (ret < 0)
goto err3;

help->helper = helper;
}

#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
if (info->timeout[0]) {
typeof(nf_ct_timeout_find_get_hook) timeout_find_get;
struct nf_conn_timeout *timeout_ext;

rcu_read_lock();
timeout_find_get =
rcu_dereference(nf_ct_timeout_find_get_hook);

if (timeout_find_get) {
const struct ipt_entry *e = par->entryinfo;
struct nf_conntrack_l4proto *l4proto;

if (e->ip.invflags & IPT_INV_PROTO) {
ret = -EINVAL;
pr_info("You cannot use inversion on "
"L4 protocol\n");
goto err4;
}
timeout = timeout_find_get(info->timeout);
if (timeout == NULL) {
ret = -ENOENT;
pr_info("No such timeout policy \"%s\"\n",
info->timeout);
goto err4;
}
if (timeout->l3num != par->family) {
ret = -EINVAL;
pr_info("Timeout policy `%s' can only be "
"used by L3 protocol number %d\n",
info->timeout, timeout->l3num);
goto err5;
}
/* Make sure the timeout policy matches any existing
* protocol tracker, otherwise default to generic.
*/
l4proto = __nf_ct_l4proto_find(par->family,
e->ip.proto);
if (timeout->l4proto->l4proto != l4proto->l4proto) {
ret = -EINVAL;
pr_info("Timeout policy `%s' can only be "
"used by L4 protocol number %d\n",
info->timeout,
timeout->l4proto->l4proto);
goto err5;
}
timeout_ext = nf_ct_timeout_ext_add(ct, timeout,
GFP_ATOMIC);
if (timeout_ext == NULL) {
ret = -ENOMEM;
goto err5;
}
} else {
ret = -ENOENT;
pr_info("Timeout policy base is empty\n");
goto err4;
}
rcu_read_unlock();
ret = xt_ct_set_timeout(ct, par, info->timeout);
if (ret < 0)
goto err3;
}
#endif

__set_bit(IPS_TEMPLATE_BIT, &ct->status);
__set_bit(IPS_CONFIRMED_BIT, &ct->status);
out:
info->ct = ct;
return 0;

#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
err5:
__xt_ct_tg_timeout_put(timeout);
err4:
rcu_read_unlock();
#endif
err3:
nf_conntrack_free(ct);
err2:
Expand All @@ -330,33 +315,38 @@ static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
nf_ct_put(info->ct);
}

static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
static void xt_ct_destroy_timeout(struct nf_conn *ct)
{
struct xt_ct_target_info_v1 *info = par->targinfo;
struct nf_conn *ct = info->ct;
struct nf_conn_help *help;
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
struct nf_conn_timeout *timeout_ext;
typeof(nf_ct_timeout_put_hook) timeout_put;

rcu_read_lock();
timeout_put = rcu_dereference(nf_ct_timeout_put_hook);

if (timeout_put) {
timeout_ext = nf_ct_timeout_find(ct);
if (timeout_ext)
timeout_put(timeout_ext->timeout);
}
rcu_read_unlock();
#endif
}

static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
{
struct xt_ct_target_info_v1 *info = par->targinfo;
struct nf_conn *ct = info->ct;
struct nf_conn_help *help;

if (!nf_ct_is_untracked(ct)) {
help = nfct_help(ct);
if (help)
module_put(help->helper->me);

nf_ct_l3proto_module_put(par->family);

#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
rcu_read_lock();
timeout_put = rcu_dereference(nf_ct_timeout_put_hook);

if (timeout_put) {
timeout_ext = nf_ct_timeout_find(ct);
if (timeout_ext)
timeout_put(timeout_ext->timeout);
}
rcu_read_unlock();
#endif
xt_ct_destroy_timeout(ct);
}
nf_ct_put(info->ct);
}
Expand Down

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