It reworks the current atomic API:
- propose START/COMMIT/ABORT transaction messages
- remove rule flags: rule manipalution is part of a transaction once
one has been started
- Enable 1 transaction per-client
- 1 commit at a time (mutex based)
---
Hi,
Ok I tried now to fix a bit better the proposal.
The nft message first are more like the other ones:
-> not too long, and the meaningful part is concatenated.
@Pablo: I took your idea of "BEGIN" instead of "START", it sounds better.
I still believe we should enable 1 transaction per-client so now instead
of the bogus sk_user_data pointer, it stores the client transaction in a local
list. I did not yet put a limit on how many clients can start a transaction actually,
it has to be added.
It's actually cleaner that way.
I also refactored a bit the nf_tables_newrule(), it's cleaner and optimized.
(no list_del_rcu(rule) in case of not added properly to the transaction)
About the commit, you are right Pablo: only one at a time, this is mandatory.
I missed the point on my first proposal.
To do so I introduced a mutex. If it's already locked it return -EAGAIN, so it's up
to the client to retry. I guess this is anyway not going to happen very often.
I don't know if we could get something better here, at least now no client can
lock up the other indefinitely, it enables per-client transaction...
Please review,
include/net/netfilter/nf_tables.h | 11 ++
include/uapi/linux/netfilter/nf_tables.h | 11 +-
net/netfilter/nf_tables_api.c | 216 +++++++++++++++++++------------
3 files changed, 150 insertions(+), 88 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 69cb5ea..028f832 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -354,6 +354,17 @@ struct nft_rule_update {
struct net *net;
};
+/**
+ * struct nft_transaction - nf_tables transaction
+ *
+ * @updates: list of rule updates for the current transaction
+ */
+struct nft_transaction {
+ struct list_head list;
+ struct list_head updates;
+ u32 pid_owner;
+};
+
static inline struct nft_expr *nft_expr_first(const struct nft_rule *rule)
{
return (struct nft_expr *)&rule->data[0];
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 76b215f..5f3251b 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -37,8 +37,9 @@ enum nf_tables_msg_types {
NFT_MSG_NEWSETELEM,
NFT_MSG_GETSETELEM,
NFT_MSG_DELSETELEM,
- NFT_MSG_COMMIT,
- NFT_MSG_ABORT,
+ NFT_MSG_BEGINTRANSACT,
+ NFT_MSG_COMMITTRANSACT,
+ NFT_MSG_ABORTTRANSACT,
NFT_MSG_MAX,
};
@@ -88,18 +89,12 @@ enum nft_chain_attributes {
};
#define NFTA_CHAIN_MAX (__NFTA_CHAIN_MAX - 1)
-enum {
- NFT_RULE_F_COMMIT = (1 << 0),
- NFT_RULE_F_MASK = NFT_RULE_F_COMMIT,
-};
-
enum nft_rule_attributes {
NFTA_RULE_UNSPEC,
NFTA_RULE_TABLE,
NFTA_RULE_CHAIN,
NFTA_RULE_HANDLE,
NFTA_RULE_EXPRESSIONS,
- NFTA_RULE_FLAGS,
NFTA_RULE_COMPAT,
__NFTA_RULE_MAX
};
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index d2da5df..0bc6318 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -11,6 +11,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
+#include <linux/mutex.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
@@ -22,6 +23,8 @@
#include <net/sock.h>
static LIST_HEAD(nf_tables_expressions);
+static LIST_HEAD(nf_tables_transactions);
+static DEFINE_MUTEX(nf_tables_commit_lock);
/**
* nft_register_afinfo - register nf_tables address family info
@@ -1264,7 +1267,6 @@ static const struct nla_policy nft_rule_policy[NFTA_RULE_MAX + 1] = {
.len = NFT_CHAIN_MAXNAMELEN - 1 },
[NFTA_RULE_HANDLE] = { .type = NLA_U64 },
[NFTA_RULE_EXPRESSIONS] = { .type = NLA_NESTED },
- [NFTA_RULE_FLAGS] = { .type = NLA_U32 },
[NFTA_RULE_COMPAT] = { .type = NLA_NESTED },
};
@@ -1518,15 +1520,35 @@ static void nf_tables_rule_destroy(struct nft_rule *rule)
static struct nft_expr_info *info;
-static int nf_tables_dirty_add(struct nft_rule *rule, const struct nft_ctx *ctx)
+static struct nft_transaction *nf_tables_transaction_lookup(u32 pid_owner)
{
- struct nft_rule_update *rupd;
+ struct nft_transaction *transaction;
- /* Another socket owns the dirty list? */
- if (!ctx->net->nft.pid_owner)
- ctx->net->nft.pid_owner = ctx->nlh->nlmsg_pid;
- else if (ctx->net->nft.pid_owner != ctx->nlh->nlmsg_pid)
- return -EBUSY;
+ if (list_empty(&nf_tables_transactions))
+ return NULL;
+
+ list_for_each_entry(transaction, &nf_tables_transactions, list) {
+ if (pid_owner == transaction->pid_owner)
+ return transaction;
+ }
+
+ return NULL;
+}
+
+static void nf_tables_transaction_remove(struct nft_transaction *transaction)
+{
+ nfnl_lock();
+ list_del(&transaction->list);
+ nfnl_unlock();
+
+ kfree(transaction);
+}
+
+static int nf_tables_transaction_add(const struct nft_ctx *ctx,
+ struct nft_transaction *transaction,
+ struct nft_rule *rule)
+{
+ struct nft_rule_update *rupd;
rupd = kmalloc(sizeof(struct nft_rule_update), GFP_KERNEL);
if (rupd == NULL)
@@ -1536,7 +1558,7 @@ static int nf_tables_dirty_add(struct nft_rule *rule, const struct nft_ctx *ctx)
rupd->table = ctx->table;
rupd->rule = rule;
rupd->net = ctx->net;
- list_add(&rupd->list, &ctx->net->nft.dirty_rules);
+ list_add(&rupd->list, &transaction->updates);
return 0;
}
@@ -1547,6 +1569,7 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
{
const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
const struct nft_af_info *afi;
+ struct nft_transaction *transaction;
struct net *net = sock_net(skb->sk);
struct nft_table *table;
struct nft_chain *chain;
@@ -1557,7 +1580,6 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
unsigned int size, i, n;
int err, rem;
bool create;
- u32 flags = 0;
u64 handle;
create = nlh->nlmsg_flags & NLM_F_CREATE ? true : false;
@@ -1616,15 +1638,6 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
if (rule == NULL)
goto err1;
- if (nla[NFTA_RULE_FLAGS]) {
- flags = ntohl(nla_get_be32(nla[NFTA_RULE_FLAGS]));
- if (flags & ~NFT_RULE_F_MASK)
- return -EINVAL;
-
- if (flags & NFT_RULE_F_COMMIT)
- nft_rule_activate_next(net, rule);
- }
-
rule->handle = handle;
rule->dlen = size;
@@ -1637,8 +1650,16 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
expr = nft_expr_next(expr);
}
+ transaction = nf_tables_transaction_lookup(nlh->nlmsg_pid);
+ if (transaction != NULL) {
+ err = nf_tables_transaction_add(&ctx, transaction, rule);
+ if (err < 0)
+ goto err2;
+ nft_rule_activate_next(net, rule);
+ }
+
if (nlh->nlmsg_flags & NLM_F_REPLACE) {
- if (flags & NFT_RULE_F_COMMIT) {
+ if (transaction != NULL) {
nft_rule_disactivate_next(net, old_rule);
list_add_tail_rcu(&rule->list, &chain->rules);
} else {
@@ -1650,16 +1671,11 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
else
list_add_rcu(&rule->list, &chain->rules);
- if (flags & NFT_RULE_F_COMMIT) {
- err = nf_tables_dirty_add(rule, &ctx);
- if (err < 0) {
- list_del_rcu(&rule->list);
- goto err2;
- }
- } else {
+ if (transaction == NULL) {
nf_tables_rule_notify(skb, nlh, table, chain, rule,
NFT_MSG_NEWRULE,
- nlh->nlmsg_flags & (NLM_F_APPEND | NLM_F_REPLACE),
+ nlh->nlmsg_flags &
+ (NLM_F_APPEND | NLM_F_REPLACE),
nfmsg->nfgen_family);
}
return 0;
@@ -1674,17 +1690,18 @@ err1:
return err;
}
-static int
-nf_tables_delrule_one(struct nft_ctx *ctx, struct nft_rule *rule, u32 flags)
+static int nf_tables_delrule_one(struct nft_ctx *ctx,
+ struct nft_transaction *transaction,
+ struct nft_rule *rule)
{
int ret = 0;
- if (flags & NFT_RULE_F_COMMIT) {
+ if (transaction != NULL) {
/* Will be deleted already in the next generation */
if (!nft_rule_is_active_next(ctx->net, rule))
return -EBUSY;
- ret = nf_tables_dirty_add(rule, ctx);
+ ret = nf_tables_transaction_add(ctx, transaction, rule);
if (ret >= 0)
nft_rule_disactivate_next(ctx->net, rule);
} else {
@@ -1703,13 +1720,13 @@ static int nf_tables_delrule(struct sock *nlsk, struct sk_buff *skb,
{
const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
const struct nft_af_info *afi;
+ struct nft_transaction *transaction;
struct net *net = sock_net(skb->sk);
const struct nft_table *table;
struct nft_chain *chain;
struct nft_rule *rule, *tmp;
int family = nfmsg->nfgen_family, err;
struct nft_ctx ctx;
- u32 flags = 0;
afi = nf_tables_afinfo_lookup(net, family, false);
if (IS_ERR(afi))
@@ -1725,44 +1742,68 @@ static int nf_tables_delrule(struct sock *nlsk, struct sk_buff *skb,
nft_ctx_init(&ctx, skb, nlh, afi, table, chain, nla);
- if (nla[NFTA_RULE_FLAGS]) {
- flags = ntohl(nla_get_be32(nla[NFTA_RULE_FLAGS]));
-
- if (flags & ~NFT_RULE_F_MASK)
- return -EINVAL;
- }
+ transaction = nf_tables_transaction_lookup(nlh->nlmsg_pid);
if (nla[NFTA_RULE_HANDLE]) {
rule = nf_tables_rule_lookup(chain, nla[NFTA_RULE_HANDLE]);
if (IS_ERR(rule))
return PTR_ERR(rule);
- err = nf_tables_delrule_one(&ctx, rule, flags);
+ err = nf_tables_delrule_one(&ctx, transaction, rule);
if (err < 0)
return err;
} else {
/* Remove all rules in this chain */
list_for_each_entry_safe(rule, tmp, &chain->rules, list)
- nf_tables_delrule_one(&ctx, rule, flags);
+ nf_tables_delrule_one(&ctx, transaction, rule);
}
return 0;
}
-static int nf_tables_commit(struct sock *nlsk, struct sk_buff *skb,
- const struct nlmsghdr *nlh,
- const struct nlattr * const nla[])
+static int nf_tables_begin_transaction(struct sock *nlsk, struct sk_buff *skb,
+ const struct nlmsghdr *nlh,
+ const struct nlattr * const nla[])
+{
+ struct nft_transaction *transaction;
+
+ transaction = nf_tables_transaction_lookup(nlh->nlmsg_pid);
+ if (transaction != NULL)
+ return -EALREADY;
+
+ transaction = kmalloc(sizeof(struct nft_transaction), GFP_KERNEL);
+ if (transaction == NULL)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&transaction->list);
+ INIT_LIST_HEAD(&transaction->updates);
+ transaction->pid_owner = nlh->nlmsg_pid;
+
+ nfnl_lock();
+ list_add_tail(&transaction->list, &nf_tables_transactions);
+ nfnl_unlock();
+
+ return 0;
+}
+
+static int nf_tables_commit_transaction(struct sock *nlsk, struct sk_buff *skb,
+ const struct nlmsghdr *nlh,
+ const struct nlattr * const nla[])
{
const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
const struct nft_af_info *afi;
+ struct nft_transaction *transaction;
struct net *net = sock_net(skb->sk);
struct nft_rule_update *rupd, *tmp;
int family = nfmsg->nfgen_family;
bool create;
- /* Are you the owner of the dirty list? */
- if (nlh->nlmsg_pid != net->nft.pid_owner)
- return -EBUSY;
+ transaction = nf_tables_transaction_lookup(nlh->nlmsg_pid);
+ if (transaction == NULL)
+ return -EINVAL;
+
+ if (list_empty(&transaction->updates))
+ goto done;
create = nlh->nlmsg_flags & NLM_F_CREATE ? true : false;
@@ -1770,6 +1811,10 @@ static int nf_tables_commit(struct sock *nlsk, struct sk_buff *skb,
if (IS_ERR(afi))
return PTR_ERR(afi);
+ /* Check if a commit is on-going */
+ if (mutex_trylock(&nf_tables_commit_lock))
+ return -EAGAIN;
+
/* Bump generation counter, invalidate any dump in progress */
net->nft.genctr++;
@@ -1781,7 +1826,7 @@ static int nf_tables_commit(struct sock *nlsk, struct sk_buff *skb,
*/
synchronize_rcu();
- list_for_each_entry_safe(rupd, tmp, &net->nft.dirty_rules, list) {
+ list_for_each_entry_safe(rupd, tmp, &transaction->updates, list) {
/* Delete this rule from the dirty list */
list_del(&rupd->list);
@@ -1806,47 +1851,49 @@ static int nf_tables_commit(struct sock *nlsk, struct sk_buff *skb,
nf_tables_rule_destroy(rupd->rule);
kfree(rupd);
}
- /* Clear owner of this dirty list */
- net->nft.pid_owner = 0;
+ /* Release the commit lock */
+ mutex_unlock(&nf_tables_commit_lock);
+
+done:
+ nf_tables_transaction_remove(transaction);
return 0;
}
-static void nf_tables_abort_all(struct net *net)
+static void nf_tables_abort_all(struct nft_transaction *transaction)
{
struct nft_rule_update *rupd, *tmp;
- list_for_each_entry_safe(rupd, tmp, &net->nft.dirty_rules, list) {
- /* Delete all rules from the dirty list */
+ list_for_each_entry_safe(rupd, tmp, &transaction->updates, list) {
+ /* Delete all rules from the update list */
list_del(&rupd->list);
- if (!nft_rule_is_active_next(rupd->net, rupd->rule)) {
+ if (nft_rule_is_active_next(rupd->net, rupd->rule)) {
+ list_del_rcu(&rupd->rule->list);
+ nf_tables_rule_destroy(rupd->rule);
+ } else
nft_rule_clear(rupd->net, rupd->rule);
- kfree(rupd);
- return;
- }
- /* This rule is inactive, get rid of it */
- list_del_rcu(&rupd->rule->list);
- nf_tables_rule_destroy(rupd->rule);
kfree(rupd);
}
- /* Clear the owner of the dirty list */
- net->nft.pid_owner = 0;
}
-static int nf_tables_abort(struct sock *nlsk, struct sk_buff *skb,
- const struct nlmsghdr *nlh,
- const struct nlattr * const nla[])
+static int nf_tables_abort_transaction(struct sock *nlsk, struct sk_buff *skb,
+ const struct nlmsghdr *nlh,
+ const struct nlattr * const nla[])
{
const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
const struct nft_af_info *afi;
+ struct nft_transaction *transaction;
struct net *net = sock_net(skb->sk);
bool create;
- /* Are you the owner of the dirty list? */
- if (nlh->nlmsg_pid != net->nft.pid_owner)
- return -EBUSY;
+ transaction = nf_tables_transaction_lookup(nlh->nlmsg_pid);
+ if (transaction == NULL)
+ return -EINVAL;
+
+ if (list_empty(&transaction->updates))
+ goto done;
create = nlh->nlmsg_flags & NLM_F_CREATE ? true : false;
@@ -1854,24 +1901,28 @@ static int nf_tables_abort(struct sock *nlsk, struct sk_buff *skb,
if (IS_ERR(afi))
return PTR_ERR(afi);
- nf_tables_abort_all(net);
+ nf_tables_abort_all(transaction);
+done:
+ nf_tables_transaction_remove(transaction);
return 0;
}
-static int
-nf_tables_rcv_nl_event(struct notifier_block *this,
- unsigned long event, void *ptr)
+static int nf_tables_rcv_nl_event(struct notifier_block *this,
+ unsigned long event, void *ptr)
{
struct netlink_notify *n = ptr;
+ struct nft_transaction *transaction;
if (event != NETLINK_URELEASE || n->protocol != NETLINK_NETFILTER)
return NOTIFY_DONE;
- if (n->portid != n->net->nft.pid_owner)
- return NOTIFY_DONE;
-
- nf_tables_abort_all(n->net);
+ transaction = nf_tables_transaction_lookup(n->net->nft.pid_owner);
+ if (transaction != NULL) {
+ if (!list_empty(&transaction->updates))
+ nf_tables_abort_all(transaction);
+ nf_tables_transaction_remove(transaction);
+ }
return NOTIFY_DONE;
}
@@ -2840,13 +2891,18 @@ 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_COMMIT] = {
- .call = nf_tables_commit,
+ [NFT_MSG_BEGINTRANSACT] = {
+ .call = nf_tables_begin_transaction,
+ .attr_count = NFTA_TABLE_MAX,
+ .policy = nft_rule_policy,
+ },
+ [NFT_MSG_COMMITTRANSACT] = {
+ .call = nf_tables_commit_transaction,
.attr_count = NFTA_TABLE_MAX,
.policy = nft_rule_policy,
},
- [NFT_MSG_ABORT] = {
- .call = nf_tables_abort,
+ [NFT_MSG_ABORTTRANSACT] = {
+ .call = nf_tables_abort_transaction,
.attr_count = NFTA_TABLE_MAX,
.policy = nft_rule_policy,
},
--
1.8.1.5
--
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