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netfilter: nf_tables: dynamically allocate hooks per net_device in fl…
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…owtables

Use a list of hooks per device instead an array.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Pablo Neira Ayuso committed Oct 23, 2019
1 parent 71a8a63 commit 3f0465a
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Showing 2 changed files with 158 additions and 103 deletions.
8 changes: 7 additions & 1 deletion include/net/netfilter/nf_tables.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -963,6 +963,12 @@ struct nft_stats {
struct u64_stats_sync syncp;
};

struct nft_hook {
struct list_head list;
struct nf_hook_ops ops;
struct rcu_head rcu;
};

/**
* struct nft_base_chain - nf_tables base chain
*
Expand Down Expand Up @@ -1173,7 +1179,7 @@ struct nft_flowtable {
use:30;
u64 handle;
/* runtime data below here */
struct nf_hook_ops *ops ____cacheline_aligned;
struct list_head hook_list ____cacheline_aligned;
struct nf_flowtable data;
};

Expand Down
253 changes: 151 additions & 102 deletions net/netfilter/nf_tables_api.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1508,6 +1508,76 @@ static void nf_tables_chain_destroy(struct nft_ctx *ctx)
}
}

static struct nft_hook *nft_netdev_hook_alloc(struct net *net,
const struct nlattr *attr)
{
struct net_device *dev;
char ifname[IFNAMSIZ];
struct nft_hook *hook;
int err;

hook = kmalloc(sizeof(struct nft_hook), GFP_KERNEL);
if (!hook) {
err = -ENOMEM;
goto err_hook_alloc;
}

nla_strlcpy(ifname, attr, IFNAMSIZ);
dev = __dev_get_by_name(net, ifname);
if (!dev) {
err = -ENOENT;
goto err_hook_dev;
}
hook->ops.dev = dev;

return hook;

err_hook_dev:
kfree(hook);
err_hook_alloc:
return ERR_PTR(err);
}

static int nf_tables_parse_netdev_hooks(struct net *net,
const struct nlattr *attr,
struct list_head *hook_list)
{
struct nft_hook *hook, *next;
const struct nlattr *tmp;
int rem, n = 0, err;

nla_for_each_nested(tmp, attr, rem) {
if (nla_type(tmp) != NFTA_DEVICE_NAME) {
err = -EINVAL;
goto err_hook;
}

hook = nft_netdev_hook_alloc(net, tmp);
if (IS_ERR(hook)) {
err = PTR_ERR(hook);
goto err_hook;
}
list_add_tail(&hook->list, hook_list);
n++;

if (n == NFT_FLOWTABLE_DEVICE_MAX) {
err = -EFBIG;
goto err_hook;
}
}
if (!n)
return -EINVAL;

return 0;

err_hook:
list_for_each_entry_safe(hook, next, hook_list, list) {
list_del(&hook->list);
kfree(hook);
}
return err;
}

struct nft_chain_hook {
u32 num;
s32 priority;
Expand Down Expand Up @@ -5628,43 +5698,6 @@ nft_flowtable_lookup_byhandle(const struct nft_table *table,
return ERR_PTR(-ENOENT);
}

static int nf_tables_parse_devices(const struct nft_ctx *ctx,
const struct nlattr *attr,
struct net_device *dev_array[], int *len)
{
const struct nlattr *tmp;
struct net_device *dev;
char ifname[IFNAMSIZ];
int rem, n = 0, err;

nla_for_each_nested(tmp, attr, rem) {
if (nla_type(tmp) != NFTA_DEVICE_NAME) {
err = -EINVAL;
goto err1;
}

nla_strlcpy(ifname, tmp, IFNAMSIZ);
dev = __dev_get_by_name(ctx->net, ifname);
if (!dev) {
err = -ENOENT;
goto err1;
}

dev_array[n++] = dev;
if (n == NFT_FLOWTABLE_DEVICE_MAX) {
err = -EFBIG;
goto err1;
}
}
if (!len)
return -EINVAL;

err = 0;
err1:
*len = n;
return err;
}

static const struct nla_policy nft_flowtable_hook_policy[NFTA_FLOWTABLE_HOOK_MAX + 1] = {
[NFTA_FLOWTABLE_HOOK_NUM] = { .type = NLA_U32 },
[NFTA_FLOWTABLE_HOOK_PRIORITY] = { .type = NLA_U32 },
Expand All @@ -5675,11 +5708,10 @@ static int nf_tables_flowtable_parse_hook(const struct nft_ctx *ctx,
const struct nlattr *attr,
struct nft_flowtable *flowtable)
{
struct net_device *dev_array[NFT_FLOWTABLE_DEVICE_MAX];
struct nlattr *tb[NFTA_FLOWTABLE_HOOK_MAX + 1];
struct nf_hook_ops *ops;
struct nft_hook *hook;
int hooknum, priority;
int err, n = 0, i;
int err;

err = nla_parse_nested_deprecated(tb, NFTA_FLOWTABLE_HOOK_MAX, attr,
nft_flowtable_hook_policy, NULL);
Expand All @@ -5697,27 +5729,21 @@ static int nf_tables_flowtable_parse_hook(const struct nft_ctx *ctx,

priority = ntohl(nla_get_be32(tb[NFTA_FLOWTABLE_HOOK_PRIORITY]));

err = nf_tables_parse_devices(ctx, tb[NFTA_FLOWTABLE_HOOK_DEVS],
dev_array, &n);
err = nf_tables_parse_netdev_hooks(ctx->net,
tb[NFTA_FLOWTABLE_HOOK_DEVS],
&flowtable->hook_list);
if (err < 0)
return err;

ops = kcalloc(n, sizeof(struct nf_hook_ops), GFP_KERNEL);
if (!ops)
return -ENOMEM;

flowtable->hooknum = hooknum;
flowtable->data.priority = priority;
flowtable->ops = ops;
flowtable->ops_len = n;

for (i = 0; i < n; i++) {
flowtable->ops[i].pf = NFPROTO_NETDEV;
flowtable->ops[i].hooknum = hooknum;
flowtable->ops[i].priority = priority;
flowtable->ops[i].priv = &flowtable->data;
flowtable->ops[i].hook = flowtable->data.type->hook;
flowtable->ops[i].dev = dev_array[i];
list_for_each_entry(hook, &flowtable->hook_list, list) {
hook->ops.pf = NFPROTO_NETDEV;
hook->ops.hooknum = hooknum;
hook->ops.priority = priority;
hook->ops.priv = &flowtable->data;
hook->ops.hook = flowtable->data.type->hook;
}

return err;
Expand Down Expand Up @@ -5757,14 +5783,51 @@ nft_flowtable_type_get(struct net *net, u8 family)
static void nft_unregister_flowtable_net_hooks(struct net *net,
struct nft_flowtable *flowtable)
{
int i;
struct nft_hook *hook;

for (i = 0; i < flowtable->ops_len; i++) {
if (!flowtable->ops[i].dev)
continue;
list_for_each_entry(hook, &flowtable->hook_list, list)
nf_unregister_net_hook(net, &hook->ops);
}

static int nft_register_flowtable_net_hooks(struct net *net,
struct nft_table *table,
struct nft_flowtable *flowtable)
{
struct nft_hook *hook, *hook2, *next;
struct nft_flowtable *ft;
int err, i = 0;

list_for_each_entry(hook, &flowtable->hook_list, list) {
list_for_each_entry(ft, &table->flowtables, list) {
list_for_each_entry(hook2, &ft->hook_list, list) {
if (hook->ops.dev == hook2->ops.dev &&
hook->ops.pf == hook2->ops.pf) {
err = -EBUSY;
goto err_unregister_net_hooks;
}
}
}

nf_unregister_net_hook(net, &flowtable->ops[i]);
err = nf_register_net_hook(net, &hook->ops);
if (err < 0)
goto err_unregister_net_hooks;

i++;
}

return 0;

err_unregister_net_hooks:
list_for_each_entry_safe(hook, next, &flowtable->hook_list, list) {
if (i-- <= 0)
break;

nf_unregister_net_hook(net, &hook->ops);
list_del_rcu(&hook->list);
kfree_rcu(hook, rcu);
}

return err;
}

static int nf_tables_newflowtable(struct net *net, struct sock *nlsk,
Expand All @@ -5775,12 +5838,13 @@ static int nf_tables_newflowtable(struct net *net, struct sock *nlsk,
{
const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
const struct nf_flowtable_type *type;
struct nft_flowtable *flowtable, *ft;
u8 genmask = nft_genmask_next(net);
int family = nfmsg->nfgen_family;
struct nft_flowtable *flowtable;
struct nft_hook *hook, *next;
struct nft_table *table;
struct nft_ctx ctx;
int err, i, k;
int err;

if (!nla[NFTA_FLOWTABLE_TABLE] ||
!nla[NFTA_FLOWTABLE_NAME] ||
Expand Down Expand Up @@ -5819,6 +5883,7 @@ static int nf_tables_newflowtable(struct net *net, struct sock *nlsk,

flowtable->table = table;
flowtable->handle = nf_tables_alloc_handle(table);
INIT_LIST_HEAD(&flowtable->hook_list);

flowtable->name = nla_strdup(nla[NFTA_FLOWTABLE_NAME], GFP_KERNEL);
if (!flowtable->name) {
Expand All @@ -5842,43 +5907,24 @@ static int nf_tables_newflowtable(struct net *net, struct sock *nlsk,
if (err < 0)
goto err4;

for (i = 0; i < flowtable->ops_len; i++) {
if (!flowtable->ops[i].dev)
continue;

list_for_each_entry(ft, &table->flowtables, list) {
for (k = 0; k < ft->ops_len; k++) {
if (!ft->ops[k].dev)
continue;

if (flowtable->ops[i].dev == ft->ops[k].dev &&
flowtable->ops[i].pf == ft->ops[k].pf) {
err = -EBUSY;
goto err5;
}
}
}

err = nf_register_net_hook(net, &flowtable->ops[i]);
if (err < 0)
goto err5;
}
err = nft_register_flowtable_net_hooks(ctx.net, table, flowtable);
if (err < 0)
goto err4;

err = nft_trans_flowtable_add(&ctx, NFT_MSG_NEWFLOWTABLE, flowtable);
if (err < 0)
goto err6;
goto err5;

list_add_tail_rcu(&flowtable->list, &table->flowtables);
table->use++;

return 0;
err6:
i = flowtable->ops_len;
err5:
for (k = i - 1; k >= 0; k--)
nf_unregister_net_hook(net, &flowtable->ops[k]);

kfree(flowtable->ops);
list_for_each_entry_safe(hook, next, &flowtable->hook_list, list) {
nf_unregister_net_hook(net, &hook->ops);
list_del_rcu(&hook->list);
kfree_rcu(hook, rcu);
}
err4:
flowtable->data.type->free(&flowtable->data);
err3:
Expand Down Expand Up @@ -5945,8 +5991,8 @@ static int nf_tables_fill_flowtable_info(struct sk_buff *skb, struct net *net,
{
struct nlattr *nest, *nest_devs;
struct nfgenmsg *nfmsg;
struct nft_hook *hook;
struct nlmsghdr *nlh;
int i;

event = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event);
nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct nfgenmsg), flags);
Expand Down Expand Up @@ -5976,11 +6022,8 @@ static int nf_tables_fill_flowtable_info(struct sk_buff *skb, struct net *net,
if (!nest_devs)
goto nla_put_failure;

for (i = 0; i < flowtable->ops_len; i++) {
const struct net_device *dev = READ_ONCE(flowtable->ops[i].dev);

if (dev &&
nla_put_string(skb, NFTA_DEVICE_NAME, dev->name))
list_for_each_entry_rcu(hook, &flowtable->hook_list, list) {
if (nla_put_string(skb, NFTA_DEVICE_NAME, hook->ops.dev->name))
goto nla_put_failure;
}
nla_nest_end(skb, nest_devs);
Expand Down Expand Up @@ -6171,7 +6214,12 @@ static void nf_tables_flowtable_notify(struct nft_ctx *ctx,

static void nf_tables_flowtable_destroy(struct nft_flowtable *flowtable)
{
kfree(flowtable->ops);
struct nft_hook *hook, *next;

list_for_each_entry_safe(hook, next, &flowtable->hook_list, list) {
list_del_rcu(&hook->list);
kfree(hook);
}
kfree(flowtable->name);
flowtable->data.type->free(&flowtable->data);
module_put(flowtable->data.type->owner);
Expand Down Expand Up @@ -6211,14 +6259,15 @@ static int nf_tables_fill_gen_info(struct sk_buff *skb, struct net *net,
static void nft_flowtable_event(unsigned long event, struct net_device *dev,
struct nft_flowtable *flowtable)
{
int i;
struct nft_hook *hook;

for (i = 0; i < flowtable->ops_len; i++) {
if (flowtable->ops[i].dev != dev)
list_for_each_entry(hook, &flowtable->hook_list, list) {
if (hook->ops.dev != dev)
continue;

nf_unregister_net_hook(dev_net(dev), &flowtable->ops[i]);
flowtable->ops[i].dev = NULL;
nf_unregister_net_hook(dev_net(dev), &hook->ops);
list_del_rcu(&hook->list);
kfree_rcu(hook, rcu);
break;
}
}
Expand Down

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