From nobody Thu Nov 27 14:00:52 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF5B133AD9A for ; Wed, 12 Nov 2025 16:25:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762964724; cv=none; b=VT+sKhXF8691fd9pEH/NQthSgAFBlbsUV9b88lbDml+Yv/PQEXx2Zz2S6Sd5yzOgJVT8xnmHi5plb23h42XUmSHEluWMfe+JbwXS/EF0qlNac4SjxYglnpQoOsDVvumUg3AxDpLvNlI28Cjos+wukwgLTfk5GpKp1f+cDcoBr04= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762964724; c=relaxed/simple; bh=bOQsq2XrOhtU0EBb/p1+2MsayISWWKNP/oCn0/irc+4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=QCfU3PQ8IdX7F44dIVKDFej44hgVWNd9tz6gNwUCHCrmAAfIIt43K3AKx/OOR/k1gn8FmmalbhrVLc52LMNWcawGDqEbAzh/tmz802HMwfOJztjUaV8H2NUXZHZ7EuXYqOCnh30QPbj2vxXQa1KuyWjgTrTzU9Iaec153v8kgXM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FdiAEzit; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FdiAEzit" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2BA8CC19422; Wed, 12 Nov 2025 16:25:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762964724; bh=bOQsq2XrOhtU0EBb/p1+2MsayISWWKNP/oCn0/irc+4=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=FdiAEzit1vc4SEfPsRJhkuFalgcOU1gT38qJ9uSHDZn8eY5XRs0FErM256qDmrYX/ 9PJBX/VpQP/NUwqAS8HoeqM8E344gfM71Pt6vueFlwmvIeQwGJ0QufxdCUdKnVxFAC o/rOmdKUCMu1DFMthR66Dovr/789llY7Vcq7aAUqySht3QkIMKvdwvRBFqSiLpQc+A 5pjjVCMkZKGzFpzH3w4iZYOWmO2oqqxP+rJm/3SNSCkh5430B1RMYVICd/UKsDHrcj vDE0MKfCCEp3Bk98bNV03hECzdBPbHPNcvQhqvWKet7hU4pegU2YIZyaNtK0w/DgTi IzmiIbFy+0oHw== From: "Matthieu Baerts (NGI0)" Date: Wed, 12 Nov 2025 17:24:48 +0100 Subject: [PATCH iproute-mptcp 5/6] mptcp: monitor: add 'deny join id0' info Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251112-laminar-v1-5-e23dbf584aa4@kernel.org> References: <20251112-laminar-v1-0-e23dbf584aa4@kernel.org> In-Reply-To: <20251112-laminar-v1-0-e23dbf584aa4@kernel.org> To: MPTCP Linux Cc: "Matthieu Baerts (NGI0)" X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=2296; i=matttbe@kernel.org; h=from:subject:message-id; bh=bOQsq2XrOhtU0EBb/p1+2MsayISWWKNP/oCn0/irc+4=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGDJFtrw1mrq5tdziZ7Cq4rz1tVvnZryoPRs1M2RZX/irB 35Hj2e+7ihlYRDjYpAVU2SRbovMn/m8irfEy88CZg4rE8gQBi5OAZjI5wyGvzK3Jba43BCLz/8c /3ZxrLTvqWunt+RN5z4/SyJxSjSjszcjwwf1lXvudWrsYo30cudJ/19oeeBCbuGMeSYfz0y5Nmv peXYA X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Until recently, the 'flags' attribute was not used. This has recently been changed with the introduction of the 'deny_join_id0' flag [1]. This flag is set when a connection is created and the other peer set the 'C' flag in the MP_CAPABLE packets [2]. This flag can be set to tell the other side that the peer will not accept extra subflows requests sent to its initial IP address and port: typically set by a server behind a legacy Layer 4 load balancer. Now, when this flag is set, "deny_join_id0" will be printed instead of "flags=3D1". Unknown remaining flags will be printed in hexadecimal at the end, e.g. "flags=3D0x2". Link: https://git.kernel.org/torvalds/c/2293c57484ae [1] Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.1-20.6 [2] Signed-off-by: Matthieu Baerts (NGI0) --- ip/ipmptcp.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/ip/ipmptcp.c b/ip/ipmptcp.c index aaacc0a5..01f6906f 100644 --- a/ip/ipmptcp.c +++ b/ip/ipmptcp.c @@ -477,6 +477,7 @@ static int mptcp_monitor_msg(struct rtnl_ctrl_data *ctr= l, const struct genlmsghdr *ghdr =3D NLMSG_DATA(n); struct rtattr *tb[MPTCP_ATTR_MAX + 1]; int len =3D n->nlmsg_len; + __u16 flags =3D 0; =20 len -=3D NLMSG_LENGTH(GENL_HDRLEN); if (len < 0) @@ -526,8 +527,6 @@ static int mptcp_monitor_msg(struct rtnl_ctrl_data *ctr= l, printf(" backup=3D%u", rta_getattr_u8(tb[MPTCP_ATTR_BACKUP])); if (tb[MPTCP_ATTR_ERROR]) printf(" error=3D%u", rta_getattr_u8(tb[MPTCP_ATTR_ERROR])); - if (tb[MPTCP_ATTR_FLAGS]) - printf(" flags=3D%x", rta_getattr_u16(tb[MPTCP_ATTR_FLAGS])); if (tb[MPTCP_ATTR_TIMEOUT]) printf(" timeout=3D%u", rta_getattr_u32(tb[MPTCP_ATTR_TIMEOUT])); if (tb[MPTCP_ATTR_IF_IDX]) @@ -539,6 +538,15 @@ static int mptcp_monitor_msg(struct rtnl_ctrl_data *ct= rl, if (tb[MPTCP_ATTR_SERVER_SIDE] && rta_getattr_u8(tb[MPTCP_ATTR_SERVER_SID= E])) printf(" server_side"); =20 + if (tb[MPTCP_ATTR_FLAGS]) + flags =3D rta_getattr_u16(tb[MPTCP_ATTR_FLAGS]); + if (flags & MPTCP_PM_EV_FLAG_DENY_JOIN_ID0) { + flags &=3D ~MPTCP_PM_EV_FLAG_DENY_JOIN_ID0; + printf(" deny_join_id0"); + } + if (flags) /* remaining bits */ + printf(" flags=3D0x%x", flags); + puts(""); out: fflush(stdout); --=20 2.51.0