From: Paolo Abeni pabeni@redhat.com
[ Upstream commit 4cf86ae84c718333928fd2d43168a1e359a28329 ]
The address ID selection for MPJ subflows created in response to incoming ADD_ADDR option is currently unreliable: it happens at MPJ socket creation time, when the local address could be unknown.
Additionally, if the no local endpoint is available for the local address, a new dummy endpoint is created, confusing the user-land.
This change refactor the code to move the address ID selection inside the rebuild_header() helper, when the local address eventually selected by the route lookup is finally known. If the address used is not mapped by any endpoint - and thus can't be advertised/removed pick the id 0 instead of allocate a new endpoint.
Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Mat Martineau mathew.j.martineau@linux.intel.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/mptcp/pm_netlink.c | 13 -------- net/mptcp/protocol.c | 3 ++ net/mptcp/protocol.h | 3 +- net/mptcp/subflow.c | 67 ++++++++++++++++++++++++++++++++++++------ 4 files changed, 63 insertions(+), 23 deletions(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index cf0f700f46dd..e6b95d1cba70 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -86,16 +86,6 @@ static bool addresses_equal(const struct mptcp_addr_info *a, return a->port == b->port; }
-static bool address_zero(const struct mptcp_addr_info *addr) -{ - struct mptcp_addr_info zero; - - memset(&zero, 0, sizeof(zero)); - zero.family = addr->family; - - return addresses_equal(addr, &zero, true); -} - static void local_address(const struct sock_common *skc, struct mptcp_addr_info *addr) { @@ -954,9 +944,6 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc) if (addresses_equal(&msk_local, &skc_local, false)) return 0;
- if (address_zero(&skc_local)) - return 0; - pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
rcu_read_lock(); diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index d6def23b8cba..c293742fc461 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -115,6 +115,9 @@ static int __mptcp_socket_create(struct mptcp_sock *msk) list_add(&subflow->node, &msk->conn_list); sock_hold(ssock->sk); subflow->request_mptcp = 1; + + /* This is the first subflow, always with id 0 */ + subflow->local_id_valid = 1; mptcp_sock_graft(msk->first, sk->sk_socket);
return 0; diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 72a259a74b57..8d70e491139a 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -436,7 +436,8 @@ struct mptcp_subflow_context { rx_eof : 1, can_ack : 1, /* only after processing the remote a key */ disposable : 1, /* ctx can be free at ulp release time */ - stale : 1; /* unable to snd/rcv data, do not use for xmit */ + stale : 1, /* unable to snd/rcv data, do not use for xmit */ + local_id_valid : 1; /* local_id is correctly initialized */ enum mptcp_data_avail data_avail; u32 remote_nonce; u64 thmac; diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 9c7deffe7cb6..204dfb82f697 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -483,6 +483,51 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) mptcp_subflow_reset(sk); }
+static void subflow_set_local_id(struct mptcp_subflow_context *subflow, int local_id) +{ + subflow->local_id = local_id; + subflow->local_id_valid = 1; +} + +static int subflow_chk_local_id(struct sock *sk) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); + struct mptcp_sock *msk = mptcp_sk(subflow->conn); + int err; + + if (likely(subflow->local_id_valid)) + return 0; + + err = mptcp_pm_get_local_id(msk, (struct sock_common *)sk); + if (err < 0) + return err; + + subflow_set_local_id(subflow, err); + return 0; +} + +static int subflow_rebuild_header(struct sock *sk) +{ + int err = subflow_chk_local_id(sk); + + if (unlikely(err < 0)) + return err; + + return inet_sk_rebuild_header(sk); +} + +#if IS_ENABLED(CONFIG_MPTCP_IPV6) +static int subflow_v6_rebuild_header(struct sock *sk) +{ + int err = subflow_chk_local_id(sk); + + if (unlikely(err < 0)) + return err; + + return inet6_sk_rebuild_header(sk); +} +#endif + struct request_sock_ops mptcp_subflow_request_sock_ops; EXPORT_SYMBOL_GPL(mptcp_subflow_request_sock_ops); static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops; @@ -1402,13 +1447,8 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, get_random_bytes(&subflow->local_nonce, sizeof(u32)); } while (!subflow->local_nonce);
- if (!local_id) { - err = mptcp_pm_get_local_id(msk, (struct sock_common *)ssk); - if (err < 0) - goto failed; - - local_id = err; - } + if (local_id) + subflow_set_local_id(subflow, local_id);
mptcp_pm_get_flags_and_ifindex_by_id(sock_net(sk), local_id, &flags, &ifindex); @@ -1431,7 +1471,6 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk, remote_token, local_id, remote_id); subflow->remote_token = remote_token; - subflow->local_id = local_id; subflow->remote_id = remote_id; subflow->request_join = 1; subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP); @@ -1734,15 +1773,22 @@ static void subflow_ulp_clone(const struct request_sock *req, new_ctx->token = subflow_req->token; new_ctx->ssn_offset = subflow_req->ssn_offset; new_ctx->idsn = subflow_req->idsn; + + /* this is the first subflow, id is always 0 */ + new_ctx->local_id_valid = 1; } else if (subflow_req->mp_join) { new_ctx->ssn_offset = subflow_req->ssn_offset; new_ctx->mp_join = 1; new_ctx->fully_established = 1; new_ctx->backup = subflow_req->backup; - new_ctx->local_id = subflow_req->local_id; new_ctx->remote_id = subflow_req->remote_id; new_ctx->token = subflow_req->token; new_ctx->thmac = subflow_req->thmac; + + /* the subflow req id is valid, fetched via subflow_check_req() + * and subflow_token_join_request() + */ + subflow_set_local_id(new_ctx, subflow_req->local_id); } }
@@ -1795,6 +1841,7 @@ void __init mptcp_subflow_init(void) subflow_specific.conn_request = subflow_v4_conn_request; subflow_specific.syn_recv_sock = subflow_syn_recv_sock; subflow_specific.sk_rx_dst_set = subflow_finish_connect; + subflow_specific.rebuild_header = subflow_rebuild_header;
tcp_prot_override = tcp_prot; tcp_prot_override.release_cb = tcp_release_cb_override; @@ -1807,6 +1854,7 @@ void __init mptcp_subflow_init(void) subflow_v6_specific.conn_request = subflow_v6_conn_request; subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock; subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect; + subflow_v6_specific.rebuild_header = subflow_v6_rebuild_header;
subflow_v6m_specific = subflow_v6_specific; subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit; @@ -1814,6 +1862,7 @@ void __init mptcp_subflow_init(void) subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len; subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced; subflow_v6m_specific.net_frag_header_len = 0; + subflow_v6m_specific.rebuild_header = subflow_rebuild_header;
tcpv6_prot_override = tcpv6_prot; tcpv6_prot_override.release_cb = tcp_release_cb_override;