[PATCH 6.6 192/299] mptcp: add needs_id for userspace appending addr

Greg Kroah-Hartman
2024-02-27T13:55:35Z

From: Geliang Tang <tanggeliang@kylinos.cn>

commit 6c347be62ae963b301ead8e7fa7b9973e6e0d6e1 upstream.

When userspace PM requires to create an ID 0 subflow in "userspace pm
create id 0 subflow" test like this:

userspace_pm_add_sf $ns2 10.0.3.2 0

An ID 1 subflow, in fact, is created.

Since in mptcp_pm_nl_append_new_local_addr(), 'id 0' will be treated as
no ID is set by userspace, and will allocate a new ID immediately:

if (!e->addr.id)
e->addr.id = find_next_zero_bit(pernet->id_bitmap,
MPTCP_PM_MAX_ADDR_ID + 1,
1);

To solve this issue, a new parameter needs_id is added for
mptcp_userspace_pm_append_new_local_addr() to distinguish between
whether userspace PM has set an ID 0 or whether userspace PM has
not set any address.

needs_id is true in mptcp_userspace_pm_get_local_id(), but false in
mptcp_pm_nl_announce_doit() and mptcp_pm_nl_subflow_create_doit().

Fixes: e5ed101a6028 ("mptcp: userspace pm allow creating id 0 subflow")
Cc: stable@vger.kernel.org
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/mptcp/pm_userspace.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -26,7 +26,8 @@ void mptcp_free_local_addr_list(struct m
}

static int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
- struct mptcp_pm_addr_entry *entry)
+ struct mptcp_pm_addr_entry *entry,
+ bool needs_id)
{
DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
struct mptcp_pm_addr_entry *match = NULL;
@@ -41,7 +42,7 @@ static int mptcp_userspace_pm_append_new
spin_lock_bh(&msk->pm.lock);
list_for_each_entry(e, &msk->pm.userspace_pm_local_addr_list, list) {
addr_match = mptcp_addresses_equal(&e->addr, &entry->addr, true);
- if (addr_match && entry->addr.id == 0)
+ if (addr_match && entry->addr.id == 0 && needs_id)
entry->addr.id = e->addr.id;
id_match = (e->addr.id == entry->addr.id);
if (addr_match && id_match) {
@@ -64,7 +65,7 @@ static int mptcp_userspace_pm_append_new
}

*e = *entry;
- if (!e->addr.id)
+ if (!e->addr.id && needs_id)
e->addr.id = find_next_zero_bit(id_bitmap,
MPTCP_PM_MAX_ADDR_ID + 1,
1);
@@ -153,7 +154,7 @@ int mptcp_userspace_pm_get_local_id(stru
if (new_entry.addr.port == msk_sport)
new_entry.addr.port = 0;

- return mptcp_userspace_pm_append_new_local_addr(msk, &new_entry);
+ return mptcp_userspace_pm_append_new_local_addr(msk, &new_entry, true);
}

int mptcp_nl_cmd_announce(struct sk_buff *skb, struct genl_info *info)
@@ -195,7 +196,7 @@ int mptcp_nl_cmd_announce(struct sk_buff
goto announce_err;
}

- err = mptcp_userspace_pm_append_new_local_addr(msk, &addr_val);
+ err = mptcp_userspace_pm_append_new_local_addr(msk, &addr_val, false);
if (err < 0) {
GENL_SET_ERR_MSG(info, "did not match address and id");
goto announce_err;
@@ -333,7 +334,7 @@ int mptcp_nl_cmd_sf_create(struct sk_buf
}

local.addr = addr_l;
- err = mptcp_userspace_pm_append_new_local_addr(msk, &local);
+ err = mptcp_userspace_pm_append_new_local_addr(msk, &local, false);
if (err < 0) {
GENL_SET_ERR_MSG(info, "did not match address and id");
goto create_err;