[PATCH net-next 2/3] net/sched: add get_fill_size() to the five actions that lack one

[Victor Nogueira <victor@mojatatu.com>]

act_simple, act_mpls, act_nat, act_skbmod and act_connmark each have a
tcf_*_dump but no .get_fill_size callback, so tcf_action_fill_size
budgets only the shared attributes and omits the per-action
TCA_*_PARMS and option bytes the dump emits.

Add a callback to each, sized from the attributes its dump emits. Size
every optional attribute unconditionally: reading the current flags to
size it conditionally would race a concurrent replace, which can flip
the attributes between sizing and dumping.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260824153903.4143642-1-victor@mojatatu.com
Co-developed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
---
 net/sched/act_connmark.c |  6 ++++++
 net/sched/act_mpls.c     | 11 +++++++++++
 net/sched/act_nat.c      |  6 ++++++
 net/sched/act_simple.c   |  7 +++++++
 net/sched/act_skbmod.c   |  9 +++++++++
 5 files changed, 39 insertions(+)

diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
index c634af5edfcd..0b6ac6be60d2 100644
--- a/net/sched/act_connmark.c
+++ b/net/sched/act_connmark.c
@@ -236,12 +236,18 @@ static void tcf_connmark_cleanup(struct tc_action *a)
 		kfree_rcu(parms, rcu);
 }
 
+static size_t tcf_connmark_get_fill_size(const struct tc_action *act)
+{
+	return nla_total_size(sizeof(struct tc_connmark)); /* TCA_CONNMARK_PARMS */
+}
+
 static struct tc_action_ops act_connmark_ops = {
 	.kind		=	"connmark",
 	.id		=	TCA_ID_CONNMARK,
 	.owner		=	THIS_MODULE,
 	.act		=	tcf_connmark_act,
 	.dump		=	tcf_connmark_dump,
+	.get_fill_size	=	tcf_connmark_get_fill_size,
 	.init		=	tcf_connmark_init,
 	.cleanup	=	tcf_connmark_cleanup,
 	.size		=	sizeof(struct tcf_connmark_info),
diff --git a/net/sched/act_mpls.c b/net/sched/act_mpls.c
index 4ea8b2e08c3a..aa56521b7179 100644
--- a/net/sched/act_mpls.c
+++ b/net/sched/act_mpls.c
@@ -438,12 +438,23 @@ static int tcf_mpls_offload_act_setup(struct tc_action *act, void *entry_data,
 	return 0;
 }
 
+static size_t tcf_mpls_get_fill_size(const struct tc_action *act)
+{
+	return nla_total_size(sizeof(struct tc_mpls)) /* TCA_MPLS_PARMS */
+		+ nla_total_size(sizeof(u32)) /* TCA_MPLS_LABEL */
+		+ nla_total_size(sizeof(u8)) /* TCA_MPLS_TC */
+		+ nla_total_size(sizeof(u8)) /* TCA_MPLS_TTL */
+		+ nla_total_size(sizeof(u8)) /* TCA_MPLS_BOS */
+		+ nla_total_size(sizeof(u16)); /* TCA_MPLS_PROTO */
+}
+
 static struct tc_action_ops act_mpls_ops = {
 	.kind		=	"mpls",
 	.id		=	TCA_ID_MPLS,
 	.owner		=	THIS_MODULE,
 	.act		=	tcf_mpls_act,
 	.dump		=	tcf_mpls_dump,
+	.get_fill_size	=	tcf_mpls_get_fill_size,
 	.init		=	tcf_mpls_init,
 	.cleanup	=	tcf_mpls_cleanup,
 	.offload_act_setup =	tcf_mpls_offload_act_setup,
diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index abb332dee836..a201979ac7cf 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -313,12 +313,18 @@ static void tcf_nat_cleanup(struct tc_action *a)
 		kfree_rcu(parms, rcu);
 }
 
+static size_t tcf_nat_get_fill_size(const struct tc_action *act)
+{
+	return nla_total_size(sizeof(struct tc_nat)); /* TCA_NAT_PARMS */
+}
+
 static struct tc_action_ops act_nat_ops = {
 	.kind		=	"nat",
 	.id		=	TCA_ID_NAT,
 	.owner		=	THIS_MODULE,
 	.act		=	tcf_nat_act,
 	.dump		=	tcf_nat_dump,
+	.get_fill_size	=	tcf_nat_get_fill_size,
 	.init		=	tcf_nat_init,
 	.cleanup	=	tcf_nat_cleanup,
 	.size		=	sizeof(struct tcf_nat),
diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index 8e69a919b4fe..80e5084b4dbd 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -79,6 +79,12 @@ static int reset_policy(struct tc_action *a, const struct nlattr *defdata,
 	return 0;
 }
 
+static size_t tcf_simp_get_fill_size(const struct tc_action *act)
+{
+	return nla_total_size(sizeof(struct tc_defact)) /* TCA_DEF_PARMS */
+		+ nla_total_size(SIMP_MAX_DATA); /* TCA_DEF_DATA */
+}
+
 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
 	[TCA_DEF_PARMS]	= { .len = sizeof(struct tc_defact) },
 	[TCA_DEF_DATA]	= { .type = NLA_STRING, .len = SIMP_MAX_DATA },
@@ -204,6 +210,7 @@ static struct tc_action_ops act_simp_ops = {
 	.owner		=	THIS_MODULE,
 	.act		=	tcf_simp_act,
 	.dump		=	tcf_simp_dump,
+	.get_fill_size	=	tcf_simp_get_fill_size,
 	.cleanup	=	tcf_simp_release,
 	.init		=	tcf_simp_init,
 	.size		=	sizeof(struct tcf_defact),
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index 7579cf1e0ff3..09e9dcf58253 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -279,12 +279,21 @@ static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a,
 	return -1;
 }
 
+static size_t tcf_skbmod_get_fill_size(const struct tc_action *act)
+{
+	return nla_total_size(sizeof(struct tc_skbmod)) /* TCA_SKBMOD_PARMS */
+		+ nla_total_size(ETH_ALEN) /* TCA_SKBMOD_DMAC */
+		+ nla_total_size(ETH_ALEN) /* TCA_SKBMOD_SMAC */
+		+ nla_total_size(sizeof(u16)); /* TCA_SKBMOD_ETYPE */
+}
+
 static struct tc_action_ops act_skbmod_ops = {
 	.kind		=	"skbmod",
 	.id		=	TCA_ACT_SKBMOD,
 	.owner		=	THIS_MODULE,
 	.act		=	tcf_skbmod_act,
 	.dump		=	tcf_skbmod_dump,
+	.get_fill_size	=	tcf_skbmod_get_fill_size,
 	.init		=	tcf_skbmod_init,
 	.cleanup	=	tcf_skbmod_cleanup,
 	.size		=	sizeof(struct tcf_skbmod),
-- 
2.43.0