@@ -858,6 +858,8 @@ enum nft_chain_flags {
* @name: name of the chain
*/
struct nft_chain {
+ struct nft_rule *__rcu *rules_gen_0;
+ struct nft_rule *__rcu *rules_gen_1;
struct list_head rules;
struct list_head list;
struct nft_table *table;
@@ -867,6 +869,9 @@ struct nft_chain {
u8 flags:6,
genmask:2;
char *name;
+
+ /* Only used during control plane commit phase: */
+ struct nft_rule **rules_next;
};
enum nft_chain_types {
@@ -1237,12 +1237,29 @@ static void nft_chain_stats_replace(struct nft_base_chain *chain,
rcu_assign_pointer(chain->stats, newstats);
}
+static void nf_tables_chain_free_chain_rules(struct nft_chain *chain)
+{
+ struct nft_rule **g0 = rcu_dereference_raw(chain->rules_gen_0);
+ struct nft_rule **g1 = rcu_dereference_raw(chain->rules_gen_1);
+
+ if (g0 != g1)
+ kvfree(g1);
+ kvfree(g0);
+
+ /* should be NULL either via abort or via successful commit */
+ WARN_ON_ONCE(chain->rules_next);
+ kvfree(chain->rules_next);
+}
+
static void nf_tables_chain_destroy(struct nft_ctx *ctx)
{
struct nft_chain *chain = ctx->chain;
BUG_ON(chain->use > 0);
+ /* no concurrent access possible anymore */
+ nf_tables_chain_free_chain_rules(chain);
+
if (nft_is_base_chain(chain)) {
struct nft_base_chain *basechain = nft_base_chain(chain);
@@ -1335,6 +1352,27 @@ static void nft_chain_release_hook(struct nft_chain_hook *hook)
module_put(hook->type->owner);
}
+struct nft_rules_old {
+ struct rcu_head h;
+ struct nft_rule **start;
+};
+
+static struct nft_rule **nf_tables_chain_alloc_rules(const struct nft_chain *chain,
+ unsigned int alloc)
+{
+ if (alloc > INT_MAX)
+ return NULL;
+
+ alloc += 1; /* NULL, ends rules */
+ if (sizeof(struct nft_rule *) > INT_MAX / alloc)
+ return NULL;
+
+ alloc *= sizeof(struct nft_rule *);
+ alloc += sizeof(struct nft_rules_old);
+
+ return kvmalloc(alloc, GFP_KERNEL);
+}
+
static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
u8 policy, bool create)
{
@@ -1344,6 +1382,7 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
struct nft_stats __percpu *stats;
struct net *net = ctx->net;
struct nft_chain *chain;
+ struct nft_rule **rules;
int err;
if (table->use == UINT_MAX)
@@ -1406,6 +1445,16 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
goto err1;
}
+ rules = nf_tables_chain_alloc_rules(chain, 0);
+ if (!rules) {
+ err = -ENOMEM;
+ goto err1;
+ }
+
+ *rules = NULL;
+ rcu_assign_pointer(chain->rules_gen_0, rules);
+ rcu_assign_pointer(chain->rules_gen_1, rules);
+
err = nf_tables_register_hook(net, table, chain);
if (err < 0)
goto err1;
@@ -5850,21 +5899,162 @@ static void nf_tables_commit_release(struct net *net)
}
}
+static int nf_tables_commit_chain_prepare(struct net *net, struct nft_chain *chain)
+{
+ struct nft_rule *rule;
+ unsigned int alloc = 0;
+ int i;
+
+ /* already handled or inactive chain? */
+ if (chain->rules_next || !nft_is_active_next(net, chain))
+ return 0;
+
+ rule = list_entry(&chain->rules, struct nft_rule, list);
+ i = 0;
+
+ list_for_each_entry_continue(rule, &chain->rules, list) {
+ if (nft_is_active_next(net, rule))
+ alloc++;
+ }
+
+ chain->rules_next = nf_tables_chain_alloc_rules(chain, alloc);
+ if (!chain->rules_next)
+ return -ENOMEM;
+
+ list_for_each_entry_continue(rule, &chain->rules, list) {
+ if (nft_is_active_next(net, rule))
+ chain->rules_next[i++] = rule;
+ }
+
+ chain->rules_next[i] = NULL;
+ return 0;
+}
+
+static void nf_tables_commit_chain_prepare_cancel(struct net *net)
+{
+ struct nft_trans *trans, *next;
+
+ list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
+ struct nft_chain *chain = trans->ctx.chain;
+
+ if (trans->msg_type == NFT_MSG_NEWRULE ||
+ trans->msg_type == NFT_MSG_DELRULE) {
+ kvfree(chain->rules_next);
+ chain->rules_next = NULL;
+ }
+ }
+}
+
+static void __nf_tables_commit_chain_free_rules_old(struct rcu_head *h)
+{
+ struct nft_rules_old *o = container_of(h, struct nft_rules_old, h);
+
+ kvfree(o->start);
+}
+
+static void nf_tables_commit_chain_free_rules_old(struct nft_rule **rules)
+{
+ struct nft_rule **r = rules;
+ struct nft_rules_old *old;
+
+ while (*r)
+ r++;
+
+ r++; /* rcu_head is after end marker */
+ old = (void *) r;
+ old->start = rules;
+
+ call_rcu(&old->h, __nf_tables_commit_chain_free_rules_old);
+}
+
+static void nf_tables_commit_chain_active(struct net *net, struct nft_chain *chain)
+{
+ struct nft_rule **g0, **g1;
+ bool next_genbit;
+
+ next_genbit = nft_gencursor_next(net);
+
+ g0 = rcu_dereference_protected(chain->rules_gen_0,
+ lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES));
+ g1 = rcu_dereference_protected(chain->rules_gen_1,
+ lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES));
+
+ /* No changes to this chain? */
+ if (chain->rules_next == NULL) {
+ /* chain had no change in last or next generation */
+ if (g0 == g1)
+ return;
+ /*
+ * chain had no change in this generation; make sure next
+ * one uses same rules as current generation.
+ */
+ if (next_genbit) {
+ rcu_assign_pointer(chain->rules_gen_1, g0);
+ nf_tables_commit_chain_free_rules_old(g1);
+ } else {
+ rcu_assign_pointer(chain->rules_gen_0, g1);
+ nf_tables_commit_chain_free_rules_old(g0);
+ }
+
+ return;
+ }
+
+ if (next_genbit)
+ rcu_assign_pointer(chain->rules_gen_1, chain->rules_next);
+ else
+ rcu_assign_pointer(chain->rules_gen_0, chain->rules_next);
+
+ chain->rules_next = NULL;
+
+ if (g0 == g1)
+ return;
+
+ if (next_genbit)
+ nf_tables_commit_chain_free_rules_old(g1);
+ else
+ nf_tables_commit_chain_free_rules_old(g0);
+}
+
static int nf_tables_commit(struct net *net, struct sk_buff *skb)
{
struct nft_trans *trans, *next;
struct nft_trans_elem *te;
+ struct nft_chain *chain;
+ struct nft_table *table;
- /* Bump generation counter, invalidate any dump in progress */
- while (++net->nft.base_seq == 0);
+ /* 1. Allocate space for next generation rules_gen_X[] */
+ list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
+ int ret;
- /* A new generation has just started */
- net->nft.gencursor = nft_gencursor_next(net);
+ if (trans->msg_type == NFT_MSG_NEWRULE ||
+ trans->msg_type == NFT_MSG_DELRULE) {
+ chain = trans->ctx.chain;
+
+ ret = nf_tables_commit_chain_prepare(net, chain);
+ if (ret < 0) {
+ nf_tables_commit_chain_prepare_cancel(net);
+ return ret;
+ }
+ }
+ }
- /* Make sure all packets have left the previous generation before
- * purging old rules.
+ /* step 2. Make rules_gen_X visible to packet path */
+ list_for_each_entry(table, &net->nft.tables, list) {
+ list_for_each_entry(chain, &table->chains, list) {
+ if (!nft_is_active_next(net, chain))
+ continue;
+ nf_tables_commit_chain_active(net, chain);
+ }
+ }
+
+ /*
+ * Bump generation counter, invalidate any dump in progress.
+ * Cannot fail after this point.
*/
- synchronize_rcu();
+ while (++net->nft.base_seq == 0);
+
+ /* step 3. Start new generation, rules_gen_X now in use. */
+ net->nft.gencursor = nft_gencursor_next(net);
list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
switch (trans->msg_type) {
@@ -133,7 +133,7 @@ static noinline void nft_update_chain_stats(const struct nft_chain *chain,
struct nft_jumpstack {
const struct nft_chain *chain;
- const struct nft_rule *rule;
+ struct nft_rule *const *rules;
};
unsigned int
@@ -141,27 +141,29 @@ nft_do_chain(struct nft_pktinfo *pkt, void *priv)
{
const struct nft_chain *chain = priv, *basechain = chain;
const struct net *net = nft_net(pkt);
+ struct nft_rule *const *rules;
const struct nft_rule *rule;
const struct nft_expr *expr, *last;
struct nft_regs regs;
unsigned int stackptr = 0;
struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
- unsigned int gencursor = nft_genmask_cur(net);
+ bool genbit = READ_ONCE(net->nft.gencursor);
struct nft_traceinfo info;
info.trace = false;
if (static_branch_unlikely(&nft_trace_enabled))
nft_trace_init(&info, pkt, ®s.verdict, basechain);
do_chain:
- rule = list_entry(&chain->rules, struct nft_rule, list);
+ if (genbit)
+ rules = rcu_dereference(chain->rules_gen_1);
+ else
+ rules = rcu_dereference(chain->rules_gen_0);
+
next_rule:
+ rule = *rules;
regs.verdict.code = NFT_CONTINUE;
- list_for_each_entry_continue_rcu(rule, &chain->rules, list) {
-
- /* This rule is not active, skip. */
- if (unlikely(rule->genmask & gencursor))
- continue;
-
+ for (; *rules ; rules++) {
+ rule = *rules;
nft_rule_for_each_expr(expr, last, rule) {
if (expr->ops == &nft_cmp_fast_ops)
nft_cmp_fast_eval(expr, ®s);
@@ -199,7 +201,7 @@ nft_do_chain(struct nft_pktinfo *pkt, void *priv)
case NFT_JUMP:
BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
jumpstack[stackptr].chain = chain;
- jumpstack[stackptr].rule = rule;
+ jumpstack[stackptr].rules = rules + 1;
stackptr++;
/* fall through */
case NFT_GOTO:
@@ -221,7 +223,7 @@ nft_do_chain(struct nft_pktinfo *pkt, void *priv)
if (stackptr > 0) {
stackptr--;
chain = jumpstack[stackptr].chain;
- rule = jumpstack[stackptr].rule;
+ rules = jumpstack[stackptr].rules;
goto next_rule;
}