From: Geliang Tang <tanggeliang@kylinos.cn>

A more general way to check if MPTCP_PM_ATTR_* exists in 'info'
is to use GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_*) instead of
directly reading info->attrs[MPTCP_PM_ATTR_*] and then checking
if it's NULL.

So this patch uses GENL_REQ_ATTR_CHECK() for userspace PM in
mptcp_pm_nl_announce_doit(), mptcp_pm_nl_remove_doit(),
mptcp_pm_nl_subflow_create_doit(), mptcp_pm_nl_subflow_destroy_doit()
and mptcp_userspace_pm_get_sock().

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_userspace.c | 41 +++++++++++++++++++----------------------
 1 file changed, 19 insertions(+), 22 deletions(-)

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index 2f82ac49db35ec34dcc0b9208f4ac12edc6ab254..d6595cf3d8f8f9d4e2fd51505032ed2dc894738c 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -175,14 +175,13 @@ bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk,
 
 static struct mptcp_sock *mptcp_userspace_pm_get_sock(const struct genl_info *info)
 {
-	struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
 	struct mptcp_sock *msk;
+	struct nlattr *token;
 
-	if (!token) {
-		GENL_SET_ERR_MSG(info, "missing required token");
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_TOKEN))
 		return NULL;
-	}
 
+	token = info->attrs[MPTCP_PM_ATTR_TOKEN];
 	msk = mptcp_token_get_sock(genl_info_net(info), nla_get_u32(token));
 	if (!msk) {
 		NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
@@ -201,16 +200,14 @@ static struct mptcp_sock *mptcp_userspace_pm_get_sock(const struct genl_info *in
 
 int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	struct nlattr *addr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	struct mptcp_pm_addr_entry addr_val;
 	struct mptcp_sock *msk;
+	struct nlattr *addr;
 	int err = -EINVAL;
 	struct sock *sk;
 
-	if (!addr) {
-		GENL_SET_ERR_MSG(info, "missing required address");
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR))
 		return err;
-	}
 
 	msk = mptcp_userspace_pm_get_sock(info);
 	if (!msk)
@@ -218,6 +215,7 @@ int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
 
 	sk = (struct sock *)msk;
 
+	addr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	err = mptcp_pm_parse_entry(addr, info, true, &addr_val);
 	if (err < 0) {
 		GENL_SET_ERR_MSG(info, "error parsing local address");
@@ -319,18 +317,17 @@ void mptcp_pm_remove_addr_entry(struct mptcp_sock *msk,
 
 int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	struct nlattr *id = info->attrs[MPTCP_PM_ATTR_LOC_ID];
 	struct mptcp_pm_addr_entry *match;
 	struct mptcp_sock *msk;
+	struct nlattr *id;
 	int err = -EINVAL;
 	struct sock *sk;
 	u8 id_val;
 
-	if (!id) {
-		GENL_SET_ERR_MSG(info, "missing required ID");
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_LOC_ID))
 		return err;
-	}
 
+	id = info->attrs[MPTCP_PM_ATTR_LOC_ID];
 	id_val = nla_get_u8(id);
 
 	msk = mptcp_userspace_pm_get_sock(info);
@@ -373,19 +370,17 @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 
 int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
-	struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	struct mptcp_pm_addr_entry entry = { 0 };
 	struct mptcp_addr_info addr_r;
+	struct nlattr *raddr, *laddr;
 	struct mptcp_pm_local local;
 	struct mptcp_sock *msk;
 	int err = -EINVAL;
 	struct sock *sk;
 
-	if (!laddr || !raddr) {
-		GENL_SET_ERR_MSG(info, "missing required address(es)");
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR) ||
+	    GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR_REMOTE))
 		return err;
-	}
 
 	msk = mptcp_userspace_pm_get_sock(info);
 	if (!msk)
@@ -393,6 +388,7 @@ int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 
 	sk = (struct sock *)msk;
 
+	laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	err = mptcp_pm_parse_entry(laddr, info, true, &entry);
 	if (err < 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
@@ -406,6 +402,7 @@ int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
 	}
 	entry.flags |= MPTCP_PM_ADDR_FLAG_SUBFLOW;
 
+	raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
 	err = mptcp_pm_parse_addr(raddr, info, &addr_r);
 	if (err < 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");
@@ -498,18 +495,16 @@ static struct sock *mptcp_nl_find_ssk(struct mptcp_sock *msk,
 
 int mptcp_pm_nl_subflow_destroy_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	struct nlattr *raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
-	struct nlattr *laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	struct mptcp_pm_addr_entry addr_l;
 	struct mptcp_addr_info addr_r;
+	struct nlattr *raddr, *laddr;
 	struct mptcp_sock *msk;
 	struct sock *sk, *ssk;
 	int err = -EINVAL;
 
-	if (!laddr || !raddr) {
-		GENL_SET_ERR_MSG(info, "missing required address(es)");
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR) ||
+	    GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR_REMOTE))
 		return err;
-	}
 
 	msk = mptcp_userspace_pm_get_sock(info);
 	if (!msk)
@@ -517,12 +512,14 @@ int mptcp_pm_nl_subflow_destroy_doit(struct sk_buff *skb, struct genl_info *info
 
 	sk = (struct sock *)msk;
 
+	laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	err = mptcp_pm_parse_entry(laddr, info, true, &addr_l);
 	if (err < 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, laddr, "error parsing local addr");
 		goto destroy_err;
 	}
 
+	raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
 	err = mptcp_pm_parse_addr(raddr, info, &addr_r);
 	if (err < 0) {
 		NL_SET_ERR_MSG_ATTR(info->extack, raddr, "error parsing remote addr");

-- 
2.47.1