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netfilter: nf_tables: Introduce NFT_MSG_GETSETELEM_RESET
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Analogous to NFT_MSG_GETOBJ_RESET, but for set elements with a timeout
or attached stateful expressions like counters or quotas - reset them
all at once. Respect a per element timeout value if present to reset the
'expires' value to.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Phil Sutter authored and Pablo Neira Ayuso committed Jun 26, 2023
1 parent 4589725 commit 079cd63
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Showing 2 changed files with 50 additions and 20 deletions.
2 changes: 2 additions & 0 deletions include/uapi/linux/netfilter/nf_tables.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -105,6 +105,7 @@ enum nft_verdicts {
* @NFT_MSG_DESTROYSETELEM: destroy a set element (enum nft_set_elem_attributes)
* @NFT_MSG_DESTROYOBJ: destroy a stateful object (enum nft_object_attributes)
* @NFT_MSG_DESTROYFLOWTABLE: destroy flow table (enum nft_flowtable_attributes)
* @NFT_MSG_GETSETELEM_RESET: get set elements and reset attached stateful expressions (enum nft_set_elem_attributes)
*/
enum nf_tables_msg_types {
NFT_MSG_NEWTABLE,
Expand Down Expand Up @@ -140,6 +141,7 @@ enum nf_tables_msg_types {
NFT_MSG_DESTROYSETELEM,
NFT_MSG_DESTROYOBJ,
NFT_MSG_DESTROYFLOWTABLE,
NFT_MSG_GETSETELEM_RESET,
NFT_MSG_MAX,
};

Expand Down
68 changes: 48 additions & 20 deletions net/netfilter/nf_tables_api.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5229,7 +5229,8 @@ static const struct nla_policy nft_set_elem_list_policy[NFTA_SET_ELEM_LIST_MAX +

static int nft_set_elem_expr_dump(struct sk_buff *skb,
const struct nft_set *set,
const struct nft_set_ext *ext)
const struct nft_set_ext *ext,
bool reset)
{
struct nft_set_elem_expr *elem_expr;
u32 size, num_exprs = 0;
Expand All @@ -5242,7 +5243,7 @@ static int nft_set_elem_expr_dump(struct sk_buff *skb,

if (num_exprs == 1) {
expr = nft_setelem_expr_at(elem_expr, 0);
if (nft_expr_dump(skb, NFTA_SET_ELEM_EXPR, expr, false) < 0)
if (nft_expr_dump(skb, NFTA_SET_ELEM_EXPR, expr, reset) < 0)
return -1;

return 0;
Expand All @@ -5253,7 +5254,7 @@ static int nft_set_elem_expr_dump(struct sk_buff *skb,

nft_setelem_expr_foreach(expr, elem_expr, size) {
expr = nft_setelem_expr_at(elem_expr, size);
if (nft_expr_dump(skb, NFTA_LIST_ELEM, expr, false) < 0)
if (nft_expr_dump(skb, NFTA_LIST_ELEM, expr, reset) < 0)
goto nla_put_failure;
}
nla_nest_end(skb, nest);
Expand All @@ -5266,11 +5267,13 @@ static int nft_set_elem_expr_dump(struct sk_buff *skb,

static int nf_tables_fill_setelem(struct sk_buff *skb,
const struct nft_set *set,
const struct nft_set_elem *elem)
const struct nft_set_elem *elem,
bool reset)
{
const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv);
unsigned char *b = skb_tail_pointer(skb);
struct nlattr *nest;
u64 timeout = 0;

nest = nla_nest_start_noflag(skb, NFTA_LIST_ELEM);
if (nest == NULL)
Expand All @@ -5293,7 +5296,7 @@ static int nf_tables_fill_setelem(struct sk_buff *skb,
goto nla_put_failure;

if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPRESSIONS) &&
nft_set_elem_expr_dump(skb, set, ext))
nft_set_elem_expr_dump(skb, set, ext, reset))
goto nla_put_failure;

if (nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF) &&
Expand All @@ -5306,11 +5309,15 @@ static int nf_tables_fill_setelem(struct sk_buff *skb,
htonl(*nft_set_ext_flags(ext))))
goto nla_put_failure;

if (nft_set_ext_exists(ext, NFT_SET_EXT_TIMEOUT) &&
nla_put_be64(skb, NFTA_SET_ELEM_TIMEOUT,
nf_jiffies64_to_msecs(*nft_set_ext_timeout(ext)),
NFTA_SET_ELEM_PAD))
goto nla_put_failure;
if (nft_set_ext_exists(ext, NFT_SET_EXT_TIMEOUT)) {
timeout = *nft_set_ext_timeout(ext);
if (nla_put_be64(skb, NFTA_SET_ELEM_TIMEOUT,
nf_jiffies64_to_msecs(timeout),
NFTA_SET_ELEM_PAD))
goto nla_put_failure;
} else if (set->flags & NFT_SET_TIMEOUT) {
timeout = READ_ONCE(set->timeout);
}

if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPIRATION)) {
u64 expires, now = get_jiffies_64();
Expand All @@ -5325,6 +5332,9 @@ static int nf_tables_fill_setelem(struct sk_buff *skb,
nf_jiffies64_to_msecs(expires),
NFTA_SET_ELEM_PAD))
goto nla_put_failure;

if (reset)
*nft_set_ext_expiration(ext) = now + timeout;
}

if (nft_set_ext_exists(ext, NFT_SET_EXT_USERDATA)) {
Expand All @@ -5348,6 +5358,7 @@ struct nft_set_dump_args {
const struct netlink_callback *cb;
struct nft_set_iter iter;
struct sk_buff *skb;
bool reset;
};

static int nf_tables_dump_setelem(const struct nft_ctx *ctx,
Expand All @@ -5358,7 +5369,7 @@ static int nf_tables_dump_setelem(const struct nft_ctx *ctx,
struct nft_set_dump_args *args;

args = container_of(iter, struct nft_set_dump_args, iter);
return nf_tables_fill_setelem(args->skb, set, elem);
return nf_tables_fill_setelem(args->skb, set, elem, args->reset);
}

struct nft_set_dump_ctx {
Expand All @@ -5367,7 +5378,7 @@ struct nft_set_dump_ctx {
};

static int nft_set_catchall_dump(struct net *net, struct sk_buff *skb,
const struct nft_set *set)
const struct nft_set *set, bool reset)
{
struct nft_set_elem_catchall *catchall;
u8 genmask = nft_genmask_cur(net);
Expand All @@ -5382,7 +5393,7 @@ static int nft_set_catchall_dump(struct net *net, struct sk_buff *skb,
continue;

elem.priv = catchall->elem;
ret = nf_tables_fill_setelem(skb, set, &elem);
ret = nf_tables_fill_setelem(skb, set, &elem, reset);
break;
}

Expand All @@ -5400,6 +5411,7 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
bool set_found = false;
struct nlmsghdr *nlh;
struct nlattr *nest;
bool reset = false;
u32 portid, seq;
int event;

Expand Down Expand Up @@ -5447,8 +5459,12 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
if (nest == NULL)
goto nla_put_failure;

if (NFNL_MSG_TYPE(cb->nlh->nlmsg_type) == NFT_MSG_GETSETELEM_RESET)
reset = true;

args.cb = cb;
args.skb = skb;
args.reset = reset;
args.iter.genmask = nft_genmask_cur(net);
args.iter.skip = cb->args[0];
args.iter.count = 0;
Expand All @@ -5457,7 +5473,7 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
set->ops->walk(&dump_ctx->ctx, set, &args.iter);

if (!args.iter.err && args.iter.count == cb->args[0])
args.iter.err = nft_set_catchall_dump(net, skb, set);
args.iter.err = nft_set_catchall_dump(net, skb, set, reset);
rcu_read_unlock();

nla_nest_end(skb, nest);
Expand Down Expand Up @@ -5495,7 +5511,8 @@ static int nf_tables_fill_setelem_info(struct sk_buff *skb,
const struct nft_ctx *ctx, u32 seq,
u32 portid, int event, u16 flags,
const struct nft_set *set,
const struct nft_set_elem *elem)
const struct nft_set_elem *elem,
bool reset)
{
struct nlmsghdr *nlh;
struct nlattr *nest;
Expand All @@ -5516,7 +5533,7 @@ static int nf_tables_fill_setelem_info(struct sk_buff *skb,
if (nest == NULL)
goto nla_put_failure;

err = nf_tables_fill_setelem(skb, set, elem);
err = nf_tables_fill_setelem(skb, set, elem, reset);
if (err < 0)
goto nla_put_failure;

Expand Down Expand Up @@ -5622,7 +5639,7 @@ static int nft_setelem_get(struct nft_ctx *ctx, struct nft_set *set,
}

static int nft_get_set_elem(struct nft_ctx *ctx, struct nft_set *set,
const struct nlattr *attr)
const struct nlattr *attr, bool reset)
{
struct nlattr *nla[NFTA_SET_ELEM_MAX + 1];
struct nft_set_elem elem;
Expand Down Expand Up @@ -5666,7 +5683,8 @@ static int nft_get_set_elem(struct nft_ctx *ctx, struct nft_set *set,
return err;

err = nf_tables_fill_setelem_info(skb, ctx, ctx->seq, ctx->portid,
NFT_MSG_NEWSETELEM, 0, set, &elem);
NFT_MSG_NEWSETELEM, 0, set, &elem,
reset);
if (err < 0)
goto err_fill_setelem;

Expand All @@ -5690,6 +5708,7 @@ static int nf_tables_getsetelem(struct sk_buff *skb,
struct nft_set *set;
struct nlattr *attr;
struct nft_ctx ctx;
bool reset = false;
int rem, err = 0;

table = nft_table_lookup(net, nla[NFTA_SET_ELEM_LIST_TABLE], family,
Expand Down Expand Up @@ -5724,8 +5743,11 @@ static int nf_tables_getsetelem(struct sk_buff *skb,
if (!nla[NFTA_SET_ELEM_LIST_ELEMENTS])
return -EINVAL;

if (NFNL_MSG_TYPE(info->nlh->nlmsg_type) == NFT_MSG_GETSETELEM_RESET)
reset = true;

nla_for_each_nested(attr, nla[NFTA_SET_ELEM_LIST_ELEMENTS], rem) {
err = nft_get_set_elem(&ctx, set, attr);
err = nft_get_set_elem(&ctx, set, attr, reset);
if (err < 0) {
NL_SET_BAD_ATTR(extack, attr);
break;
Expand Down Expand Up @@ -5758,7 +5780,7 @@ static void nf_tables_setelem_notify(const struct nft_ctx *ctx,
flags |= ctx->flags & (NLM_F_CREATE | NLM_F_EXCL);

err = nf_tables_fill_setelem_info(skb, ctx, 0, portid, event, flags,
set, elem);
set, elem, false);
if (err < 0) {
kfree_skb(skb);
goto err;
Expand Down Expand Up @@ -8715,6 +8737,12 @@ static const struct nfnl_callback nf_tables_cb[NFT_MSG_MAX] = {
.attr_count = NFTA_SET_ELEM_LIST_MAX,
.policy = nft_set_elem_list_policy,
},
[NFT_MSG_GETSETELEM_RESET] = {
.call = nf_tables_getsetelem,
.type = NFNL_CB_RCU,
.attr_count = NFTA_SET_ELEM_LIST_MAX,
.policy = nft_set_elem_list_policy,
},
[NFT_MSG_DELSETELEM] = {
.call = nf_tables_delsetelem,
.type = NFNL_CB_BATCH,
Expand Down

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