From c9809f03c158f07eaa76c7dd3606fc0a184520f2 Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Fri, 19 Sep 2025 14:08:58 +0200 Subject: [PATCH 1/6] mptcp: pm: netlink: only add server-side attr when true This attribute is a boolean. No need to add it to set it to 'false'. Indeed, the default value when this attribute is not set is naturally 'false'. A few bytes can then be saved by not adding this attribute if the connection is not on the server side. This prepares the future deprecation of its attribute, in favour of a new flag. Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-1-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski --- Documentation/netlink/specs/mptcp_pm.yaml | 4 ++-- include/uapi/linux/mptcp_pm.h | 4 ++-- net/mptcp/pm_netlink.c | 4 +++- tools/testing/selftests/net/mptcp/userspace_pm.sh | 2 +- 4 files changed, 8 insertions(+), 6 deletions(-) diff --git a/Documentation/netlink/specs/mptcp_pm.yaml b/Documentation/netlink/specs/mptcp_pm.yaml index d1b4829b580a..fc47a2931014 100644 --- a/Documentation/netlink/specs/mptcp_pm.yaml +++ b/Documentation/netlink/specs/mptcp_pm.yaml @@ -28,13 +28,13 @@ definitions: traffic-patterns it can take a long time until the MPTCP_EVENT_ESTABLISHED is sent. Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport, - dport, server-side, [flags]. + dport, [server-side], [flags]. - name: established doc: >- A MPTCP connection is established (can start new subflows). Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, sport, - dport, server-side, [flags]. + dport, [server-side], [flags]. - name: closed doc: >- diff --git a/include/uapi/linux/mptcp_pm.h b/include/uapi/linux/mptcp_pm.h index 7359d34da446..bf44a5cf5b5a 100644 --- a/include/uapi/linux/mptcp_pm.h +++ b/include/uapi/linux/mptcp_pm.h @@ -16,10 +16,10 @@ * good time to allocate memory and send ADD_ADDR if needed. Depending on the * traffic-patterns it can take a long time until the MPTCP_EVENT_ESTABLISHED * is sent. Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, - * sport, dport, server-side, [flags]. + * sport, dport, [server-side], [flags]. * @MPTCP_EVENT_ESTABLISHED: A MPTCP connection is established (can start new * subflows). Attributes: token, family, saddr4 | saddr6, daddr4 | daddr6, - * sport, dport, server-side, [flags]. + * sport, dport, [server-side], [flags]. * @MPTCP_EVENT_CLOSED: A MPTCP connection has stopped. Attribute: token. * @MPTCP_EVENT_ANNOUNCED: A new address has been announced by the peer. * Attributes: token, rem_id, family, daddr4 | daddr6 [, dport]. diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 483ddbb9ec40..33a6bf536c02 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -413,7 +413,9 @@ static int mptcp_event_created(struct sk_buff *skb, if (err) return err; - if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, READ_ONCE(msk->pm.server_side))) + /* only set when it is the server side */ + if (READ_ONCE(msk->pm.server_side) && + nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, 1)) return -EMSGSIZE; if (READ_ONCE(msk->pm.remote_deny_join_id0)) diff --git a/tools/testing/selftests/net/mptcp/userspace_pm.sh b/tools/testing/selftests/net/mptcp/userspace_pm.sh index 3d45991f24ed..87323942cb8a 100755 --- a/tools/testing/selftests/net/mptcp/userspace_pm.sh +++ b/tools/testing/selftests/net/mptcp/userspace_pm.sh @@ -241,7 +241,7 @@ make_connection() print_test "Established IP${is_v6} MPTCP Connection ns2 => ns1" if [ "${client_token}" != "" ] && [ "${server_token}" != "" ] && - [ "${client_serverside}" = 0 ] && [ "${server_serverside}" = 1 ] && + [ "${client_serverside:-0}" = 0 ] && [ "${server_serverside:-0}" = 1 ] && [ "${client_nojoin:-0}" = 0 ] && [ "${server_nojoin:-0}" = 1 ] then test_pass From 3d7ae91107b839ffeeb19730a2e2a46e0054bae8 Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Fri, 19 Sep 2025 14:08:59 +0200 Subject: [PATCH 2/6] mptcp: pm: netlink: announce server-side flag Now that the 'flags' attribute is used, it seems interesting to add one flag for 'server-side', a boolean value. This is duplicating the info from the dedicated 'server-side' attribute, but it will be deprecated in the next commit, and removed in a few versions. Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-2-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski --- include/uapi/linux/mptcp.h | 1 + net/mptcp/pm_netlink.c | 11 +++++++---- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h index 5fd5b4cf75ca..95d621f6d598 100644 --- a/include/uapi/linux/mptcp.h +++ b/include/uapi/linux/mptcp.h @@ -32,6 +32,7 @@ #define MPTCP_INFO_FLAG_REMOTE_KEY_RECEIVED _BITUL(1) #define MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 _BITUL(0) +#define MPTCP_PM_EV_FLAG_SERVER_SIDE _BITUL(1) #define MPTCP_PM_ADDR_FLAG_SIGNAL (1 << 0) #define MPTCP_PM_ADDR_FLAG_SUBFLOW (1 << 1) diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 33a6bf536c02..aa0c73faaa6a 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -413,10 +413,13 @@ static int mptcp_event_created(struct sk_buff *skb, if (err) return err; - /* only set when it is the server side */ - if (READ_ONCE(msk->pm.server_side) && - nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, 1)) - return -EMSGSIZE; + if (READ_ONCE(msk->pm.server_side)) { + flags |= MPTCP_PM_EV_FLAG_SERVER_SIDE; + + /* only set when it is the server side */ + if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, 1)) + return -EMSGSIZE; + } if (READ_ONCE(msk->pm.remote_deny_join_id0)) flags |= MPTCP_PM_EV_FLAG_DENY_JOIN_ID0; From c8bc168f5f3d152b378726f89e8561ccedcb5d5c Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Fri, 19 Sep 2025 14:09:00 +0200 Subject: [PATCH 3/6] mptcp: pm: netlink: deprecate server-side attribute Now that such info is in the 'flags' attribute, it is time to deprecate the dedicated 'server-side' attribute. It will be removed in a few versions. Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-3-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski --- Documentation/netlink/specs/mptcp_pm.yaml | 1 + net/mptcp/pm_netlink.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/Documentation/netlink/specs/mptcp_pm.yaml b/Documentation/netlink/specs/mptcp_pm.yaml index fc47a2931014..ba30a40b9dbf 100644 --- a/Documentation/netlink/specs/mptcp_pm.yaml +++ b/Documentation/netlink/specs/mptcp_pm.yaml @@ -266,6 +266,7 @@ attribute-sets: - name: server-side type: u8 + doc: "Deprecated: use 'flags'" operations: list: diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index aa0c73faaa6a..d5b383870f79 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -416,7 +416,7 @@ static int mptcp_event_created(struct sk_buff *skb, if (READ_ONCE(msk->pm.server_side)) { flags |= MPTCP_PM_EV_FLAG_SERVER_SIDE; - /* only set when it is the server side */ + /* Deprecated, and only set when it is the server side */ if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, 1)) return -EMSGSIZE; } From e6c35529452e658272d370535e8c1424dbb8e5d2 Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Fri, 19 Sep 2025 14:09:01 +0200 Subject: [PATCH 4/6] selftests: mptcp: pm: get server-side flag server-side info linked to the MPTCP connect/established events can now come from the flags, in addition to the dedicated attribute. The attribute is now deprecated -- in favour of the new flag, and will be removed later on. Print this info only once. Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-4-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski --- tools/testing/selftests/net/mptcp/pm_nl_ctl.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c index 93fea3442216..d4981b76693b 100644 --- a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c +++ b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c @@ -2,6 +2,7 @@ #include #include +#include #include #include #include @@ -113,6 +114,8 @@ static int capture_events(int fd, int event_group) error(1, errno, "could not join the " MPTCP_PM_EV_GRP_NAME " mcast group"); do { + bool server_side = false; + FD_ZERO(&rfds); FD_SET(fd, &rfds); res_len = NLMSG_ALIGN(sizeof(struct nlmsghdr)) + @@ -187,18 +190,22 @@ static int capture_events(int fd, int event_group) else if (attrs->rta_type == MPTCP_ATTR_ERROR) fprintf(stderr, ",error:%u", *(__u8 *)RTA_DATA(attrs)); else if (attrs->rta_type == MPTCP_ATTR_SERVER_SIDE) - fprintf(stderr, ",server_side:%u", *(__u8 *)RTA_DATA(attrs)); + server_side = !!*(__u8 *)RTA_DATA(attrs); else if (attrs->rta_type == MPTCP_ATTR_FLAGS) { __u16 flags = *(__u16 *)RTA_DATA(attrs); /* only print when present, easier */ if (flags & MPTCP_PM_EV_FLAG_DENY_JOIN_ID0) fprintf(stderr, ",deny_join_id0:1"); + if (flags & MPTCP_PM_EV_FLAG_SERVER_SIDE) + server_side = true; } attrs = RTA_NEXT(attrs, msg_len); } } + if (server_side) + fprintf(stderr, ",server_side:1"); fprintf(stderr, "\n"); } while (1); From 5c967ebb551919661166305c0ff9422e41065c02 Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Fri, 19 Sep 2025 14:09:02 +0200 Subject: [PATCH 5/6] mptcp: use _BITUL() instead of (1 << x) Simply to use the proper way to declare bits, and to align with all other flags declared in this file. No functional changes intended. Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-5-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski --- include/uapi/linux/mptcp.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h index 95d621f6d598..15eef878690b 100644 --- a/include/uapi/linux/mptcp.h +++ b/include/uapi/linux/mptcp.h @@ -34,11 +34,11 @@ #define MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 _BITUL(0) #define MPTCP_PM_EV_FLAG_SERVER_SIDE _BITUL(1) -#define MPTCP_PM_ADDR_FLAG_SIGNAL (1 << 0) -#define MPTCP_PM_ADDR_FLAG_SUBFLOW (1 << 1) -#define MPTCP_PM_ADDR_FLAG_BACKUP (1 << 2) -#define MPTCP_PM_ADDR_FLAG_FULLMESH (1 << 3) -#define MPTCP_PM_ADDR_FLAG_IMPLICIT (1 << 4) +#define MPTCP_PM_ADDR_FLAG_SIGNAL _BITUL(0) +#define MPTCP_PM_ADDR_FLAG_SUBFLOW _BITUL(1) +#define MPTCP_PM_ADDR_FLAG_BACKUP _BITUL(2) +#define MPTCP_PM_ADDR_FLAG_FULLMESH _BITUL(3) +#define MPTCP_PM_ADDR_FLAG_IMPLICIT _BITUL(4) struct mptcp_info { __u8 mptcpi_subflows; From 1be5b82c45850f495adf67887075507d5e8a860b Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Fri, 19 Sep 2025 14:09:03 +0200 Subject: [PATCH 6/6] mptcp: remove unused returned value of check_data_fin When working on a fix modifying mptcp_check_data_fin(), I noticed the returned value was no longer used. It looks like it was used for 3 days, between commit 7ed90803a213 ("mptcp: send explicit ack on delayed ack_seq incr") and commit ea4ca586b16f ("mptcp: refine MPTCP-level ack scheduling"). This returned value can be safely removed. Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250919-net-next-mptcp-server-side-flag-v1-6-a97a5d561a8b@kernel.org Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index d9fbddb99ad0..735a209d4072 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -545,11 +545,10 @@ static void mptcp_cleanup_rbuf(struct mptcp_sock *msk, int copied) } } -static bool mptcp_check_data_fin(struct sock *sk) +static void mptcp_check_data_fin(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); u64 rcv_data_fin_seq; - bool ret = false; /* Need to ack a DATA_FIN received from a peer while this side * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. @@ -588,12 +587,10 @@ static bool mptcp_check_data_fin(struct sock *sk) break; } - ret = true; if (!__mptcp_check_fallback(msk)) mptcp_send_ack(msk); mptcp_close_wake_up(sk); } - return ret; } static void mptcp_dss_corruption(struct mptcp_sock *msk, struct sock *ssk)