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[188.141.5.72]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4463d5ee9ecsm1107145f8f.16.2026.04.27.14.10.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Apr 2026 14:10:11 -0700 (PDT) From: David Carlier To: mptcp@lists.linux.dev Cc: Matthieu Baerts , Mat Martineau , Geliang Tang , Paolo Abeni , David Carlier Subject: [PATCH mptcp-next v4 2/4] mptcp: propagate RECVERR sockopts to subflows Date: Mon, 27 Apr 2026 22:10:04 +0100 Message-ID: <21762831cbe0d70fd963dd7f0ed9e05b050a7d1f.1777324037.git.devnexen@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: <20260421223338.52743-1-devnexen@gmail.com> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Propagate IP_RECVERR/IP_RECVERR_RFC4884 and IPV6_RECVERR/IPV6_RECVERR_RFC4884 from the MPTCP socket to existing and future subflows. The setsockopt path forwards each option to every subflow via mptcp_setsockopt_all_sf(); newly-joining subflows inherit the four RECVERR bits through sync_socket_options() now that MPTCP_INET_FLAGS_MASK covers them. Suggested-by: Paolo Abeni Assisted-by: Codex:gpt-5 Signed-off-by: David Carlier --- net/mptcp/sockopt.c | 97 ++++++++++++++++++++++++++++++++++++--------- 1 file changed, 79 insertions(+), 18 deletions(-) diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index 41c9dc9cf95e..171e83e66a97 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -8,6 +8,8 @@ =20 #include #include +#include +#include #include #include #include @@ -19,7 +21,11 @@ #define MPTCP_INET_FLAGS_MASK \ (BIT(INET_FLAGS_TRANSPARENT) | \ BIT(INET_FLAGS_FREEBIND) | \ - BIT(INET_FLAGS_BIND_ADDRESS_NO_PORT)) + BIT(INET_FLAGS_BIND_ADDRESS_NO_PORT) | \ + BIT(INET_FLAGS_RECVERR) | \ + BIT(INET_FLAGS_RECVERR_RFC4884) | \ + BIT(INET_FLAGS_RECVERR6) | \ + BIT(INET_FLAGS_RECVERR6_RFC4884)) =20 static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk) { @@ -388,6 +394,41 @@ static int mptcp_setsockopt_sol_socket(struct mptcp_so= ck *msk, int optname, return -EOPNOTSUPP; } =20 +static int mptcp_setsockopt_all_sf(struct mptcp_sock *msk, int level, + int optname, sockptr_t optval, + unsigned int optlen) +{ + struct mptcp_subflow_context *subflow; + int ret =3D 0; + + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk =3D mptcp_subflow_tcp_sock(subflow); + + ret =3D tcp_setsockopt(ssk, level, optname, optval, optlen); + if (ret) + break; + } + return ret; +} + +#if IS_ENABLED(CONFIG_IPV6) +static int mptcp_setsockopt_v6_recverr(struct mptcp_sock *msk, int optname, + sockptr_t optval, unsigned int optlen) +{ + struct sock *sk =3D (struct sock *)msk; + int ret; + + ret =3D ipv6_setsockopt(sk, SOL_IPV6, optname, optval, optlen); + if (ret) + return ret; + + lock_sock(sk); + ret =3D mptcp_setsockopt_all_sf(msk, SOL_IPV6, optname, optval, optlen); + release_sock(sk); + return ret; +} +#endif + static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname, sockptr_t optval, unsigned int optlen) { @@ -430,6 +471,12 @@ static int mptcp_setsockopt_v6(struct mptcp_sock *msk,= int optname, =20 release_sock(sk); break; +#if IS_ENABLED(CONFIG_IPV6) + case IPV6_RECVERR: + case IPV6_RECVERR_RFC4884: + ret =3D mptcp_setsockopt_v6_recverr(msk, optname, optval, optlen); + break; +#endif } =20 return ret; @@ -764,6 +811,22 @@ static int mptcp_setsockopt_v4_set_tos(struct mptcp_so= ck *msk, int optname, return 0; } =20 +static int mptcp_setsockopt_v4_recverr(struct mptcp_sock *msk, int optname, + sockptr_t optval, unsigned int optlen) +{ + struct sock *sk =3D (struct sock *)msk; + int ret; + + ret =3D ip_setsockopt(sk, SOL_IP, optname, optval, optlen); + if (ret) + return ret; + + lock_sock(sk); + ret =3D mptcp_setsockopt_all_sf(msk, SOL_IP, optname, optval, optlen); + release_sock(sk); + return ret; +} + static int mptcp_setsockopt_v4(struct mptcp_sock *msk, int optname, sockptr_t optval, unsigned int optlen) { @@ -775,6 +838,9 @@ static int mptcp_setsockopt_v4(struct mptcp_sock *msk, = int optname, return mptcp_setsockopt_sol_ip_set(msk, optname, optval, optlen); case IP_TOS: return mptcp_setsockopt_v4_set_tos(msk, optname, optval, optlen); + case IP_RECVERR: + case IP_RECVERR_RFC4884: + return mptcp_setsockopt_v4_recverr(msk, optname, optval, optlen); } =20 return -EOPNOTSUPP; @@ -802,23 +868,6 @@ static int mptcp_setsockopt_first_sf_only(struct mptcp= _sock *msk, int level, int return ret; } =20 -static int mptcp_setsockopt_all_sf(struct mptcp_sock *msk, int level, - int optname, sockptr_t optval, - unsigned int optlen) -{ - struct mptcp_subflow_context *subflow; - int ret =3D 0; - - mptcp_for_each_subflow(msk, subflow) { - struct sock *ssk =3D mptcp_subflow_tcp_sock(subflow); - - ret =3D tcp_setsockopt(ssk, level, optname, optval, optlen); - if (ret) - break; - } - return ret; -} - static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname, sockptr_t optval, unsigned int optlen) { @@ -1463,6 +1512,12 @@ static int mptcp_getsockopt_v4(struct mptcp_sock *ms= k, int optname, case IP_LOCAL_PORT_RANGE: return mptcp_put_int_option(msk, optval, optlen, READ_ONCE(inet_sk(sk)->local_port_range)); + case IP_RECVERR: + return mptcp_put_int_option(msk, optval, optlen, + inet_test_bit(RECVERR, sk)); + case IP_RECVERR_RFC4884: + return mptcp_put_int_option(msk, optval, optlen, + inet_test_bit(RECVERR_RFC4884, sk)); } =20 return -EOPNOTSUPP; @@ -1483,6 +1538,12 @@ static int mptcp_getsockopt_v6(struct mptcp_sock *ms= k, int optname, case IPV6_FREEBIND: return mptcp_put_int_option(msk, optval, optlen, inet_test_bit(FREEBIND, sk)); + case IPV6_RECVERR: + return mptcp_put_int_option(msk, optval, optlen, + inet6_test_bit(RECVERR6, sk)); + case IPV6_RECVERR_RFC4884: + return mptcp_put_int_option(msk, optval, optlen, + inet6_test_bit(RECVERR6_RFC4884, sk)); } =20 return -EOPNOTSUPP; --=20 2.53.0