The initial subflow has a special local ID: 0. It is specific per connection.
When a global endpoint is deleted and re-added later, it can have a different ID -- most services managing the endpoints automatically don't force the ID to be the same as before. It is then important to track these modifications to be consistent with the ID being used for the address used by the initial subflow, not to confuse the other peer or to send the ID 0 for the wrong address.
Now when removing an endpoint, msk->mpc_endpoint_id is reset if it corresponds to this endpoint. When adding a new endpoint, the same variable is updated if the address match the one of the initial subflow.
Fixes: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- net/mptcp/pm_netlink.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 0c91d961f51f..75c8aede7026 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -1318,20 +1318,27 @@ static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info) return pm_nl_get_pernet(genl_info_net(info)); }
-static int mptcp_nl_add_subflow_or_signal_addr(struct net *net) +static int mptcp_nl_add_subflow_or_signal_addr(struct net *net, + struct mptcp_addr_info *addr) { struct mptcp_sock *msk; long s_slot = 0, s_num = 0;
while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) { struct sock *sk = (struct sock *)msk; + struct mptcp_addr_info mpc_addr;
if (!READ_ONCE(msk->fully_established) || mptcp_pm_is_userspace(msk)) goto next;
+ /* if the endp linked to the init sf is re-added with a != ID */ + mptcp_local_address((struct sock_common *)msk, &mpc_addr); + lock_sock(sk); spin_lock_bh(&msk->pm.lock); + if (mptcp_addresses_equal(addr, &mpc_addr, addr->port)) + msk->mpc_endpoint_id = addr->id; mptcp_pm_create_subflow_or_signal_addr(msk); spin_unlock_bh(&msk->pm.lock); release_sock(sk); @@ -1404,7 +1411,7 @@ int mptcp_pm_nl_add_addr_doit(struct sk_buff *skb, struct genl_info *info) goto out_free; }
- mptcp_nl_add_subflow_or_signal_addr(sock_net(skb->sk)); + mptcp_nl_add_subflow_or_signal_addr(sock_net(skb->sk), &entry->addr); return 0;
out_free: @@ -1525,6 +1532,8 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net, spin_unlock_bh(&msk->pm.lock); }
+ if (msk->mpc_endpoint_id == entry->addr.id) + msk->mpc_endpoint_id = 0; release_sock(sk);
next: