From: David Carlier <devnexen@gmail.com>
To: netdev@vger.kernel.org, mptcp@lists.linux.dev
Cc: matttbe@kernel.org, martineau@kernel.org, geliang@kernel.org,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, horms@kernel.org,
David Carlier <devnexen@gmail.com>
Subject: [PATCH 1/3] mptcp: propagate RECVERR sockopts to subflows
Date: Tue, 21 Apr 2026 16:22:09 +0100 [thread overview]
Message-ID: <20260421152216.38127-2-devnexen@gmail.com> (raw)
In-Reply-To: <20260421152216.38127-1-devnexen@gmail.com>
Propagate IP_RECVERR/IP_RECVERR_RFC4884 and
IPV6_RECVERR/IPV6_RECVERR_RFC4884 from the MPTCP socket to
existing and future subflows.
Apply the matching sockopt according to the subflow family so mixed-
family subflows stay aligned with the parent socket configuration,
including disable-time errqueue purge semantics.
Signed-off-by: David Carlier <devnexen@gmail.com>
Assisted-by: Codex:gpt-5
---
net/mptcp/sockopt.c | 125 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 125 insertions(+)
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index de90a2897d2d..b2b7ef888dff 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -8,6 +8,8 @@
#include <linux/kernel.h>
#include <linux/module.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
#include <net/sock.h>
#include <net/protocol.h>
#include <net/tcp.h>
@@ -384,6 +386,70 @@ static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
return -EOPNOTSUPP;
}
+static bool mptcp_recverr_enabled(const struct sock *sk, bool rfc4884)
+{
+ bool enabled;
+
+ enabled = rfc4884 ? inet_test_bit(RECVERR_RFC4884, sk) :
+ inet_test_bit(RECVERR, sk);
+
+#if IS_ENABLED(CONFIG_IPV6)
+ if (sk->sk_family == AF_INET6)
+ enabled |= rfc4884 ? inet6_test_bit(RECVERR6_RFC4884, sk) :
+ inet6_test_bit(RECVERR6, sk);
+#endif
+
+ return enabled;
+}
+
+static int mptcp_subflow_set_recverr(struct sock *sk, struct sock *ssk,
+ bool rfc4884)
+{
+ int level, optname, val;
+
+#if IS_ENABLED(CONFIG_IPV6)
+ if (ssk->sk_family == AF_INET6) {
+ level = SOL_IPV6;
+ optname = rfc4884 ? IPV6_RECVERR_RFC4884 : IPV6_RECVERR;
+ } else
+#endif
+ {
+ level = SOL_IP;
+ optname = rfc4884 ? IP_RECVERR_RFC4884 : IP_RECVERR;
+ }
+
+ val = mptcp_recverr_enabled(sk, rfc4884);
+ return tcp_setsockopt(ssk, level, optname, KERNEL_SOCKPTR(&val),
+ sizeof(val));
+}
+
+static int mptcp_setsockopt_v6_recverr(struct mptcp_sock *msk, int optname,
+ sockptr_t optval, unsigned int optlen)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ int ret;
+
+ ret = ipv6_setsockopt(sk, SOL_IPV6, optname, optval, optlen);
+ if (ret)
+ return ret;
+
+ lock_sock(sk);
+ sockopt_seq_inc(msk);
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ bool rfc4884 = optname == IPV6_RECVERR_RFC4884;
+
+ ret = mptcp_subflow_set_recverr(sk, ssk, rfc4884);
+ if (ret)
+ break;
+ subflow->setsockopt_seq = msk->setsockopt_seq;
+ }
+ release_sock(sk);
+
+ return ret;
+}
+
static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
@@ -426,6 +492,10 @@ static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
release_sock(sk);
break;
+ case IPV6_RECVERR:
+ case IPV6_RECVERR_RFC4884:
+ ret = mptcp_setsockopt_v6_recverr(msk, optname, optval, optlen);
+ break;
}
return ret;
@@ -760,6 +830,33 @@ static int mptcp_setsockopt_v4_set_tos(struct mptcp_sock *msk, int optname,
return 0;
}
+static int mptcp_setsockopt_v4_recverr(struct mptcp_sock *msk, int optname,
+ sockptr_t optval, unsigned int optlen)
+{
+ struct mptcp_subflow_context *subflow;
+ struct sock *sk = (struct sock *)msk;
+ int err;
+
+ err = ip_setsockopt(sk, SOL_IP, optname, optval, optlen);
+ if (err)
+ return err;
+
+ lock_sock(sk);
+ sockopt_seq_inc(msk);
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+ bool rfc4884 = optname == IP_RECVERR_RFC4884;
+
+ err = mptcp_subflow_set_recverr(sk, ssk, rfc4884);
+ if (err)
+ break;
+ subflow->setsockopt_seq = msk->setsockopt_seq;
+ }
+ release_sock(sk);
+
+ return err;
+}
+
static int mptcp_setsockopt_v4(struct mptcp_sock *msk, int optname,
sockptr_t optval, unsigned int optlen)
{
@@ -771,6 +868,9 @@ 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);
}
return -EOPNOTSUPP;
@@ -1459,6 +1559,12 @@ static int mptcp_getsockopt_v4(struct mptcp_sock *msk, 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));
}
return -EOPNOTSUPP;
@@ -1479,6 +1585,12 @@ static int mptcp_getsockopt_v6(struct mptcp_sock *msk, 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));
}
return -EOPNOTSUPP;
@@ -1536,6 +1648,7 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
{
static const unsigned int tx_rx_locks = SOCK_RCVBUF_LOCK | SOCK_SNDBUF_LOCK;
struct sock *sk = (struct sock *)msk;
+ bool recverr, recverr_rfc4884;
bool keep_open;
keep_open = sock_flag(sk, SOCK_KEEPOPEN);
@@ -1586,6 +1699,18 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk));
inet_assign_bit(BIND_ADDRESS_NO_PORT, ssk, inet_test_bit(BIND_ADDRESS_NO_PORT, sk));
WRITE_ONCE(inet_sk(ssk)->local_port_range, READ_ONCE(inet_sk(sk)->local_port_range));
+ recverr = mptcp_recverr_enabled(sk, false);
+ recverr_rfc4884 = mptcp_recverr_enabled(sk, true);
+#if IS_ENABLED(CONFIG_IPV6)
+ if (ssk->sk_family == AF_INET6) {
+ inet6_assign_bit(RECVERR6, ssk, recverr);
+ inet6_assign_bit(RECVERR6_RFC4884, ssk, recverr_rfc4884);
+ } else
+#endif
+ {
+ inet_assign_bit(RECVERR, ssk, recverr);
+ inet_assign_bit(RECVERR_RFC4884, ssk, recverr_rfc4884);
+ }
}
void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk)
--
2.53.0
next prev parent reply other threads:[~2026-04-21 15:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-21 15:22 [PATCH 0/3] mptcp: add RECVERR and MSG_ERRQUEUE support David Carlier
2026-04-21 15:22 ` David Carlier [this message]
2026-04-21 15:22 ` [PATCH 2/3] mptcp: support MSG_ERRQUEUE on the parent socket David Carlier
2026-04-21 15:22 ` [PATCH 3/3] selftests: mptcp: cover RECVERR and MSG_ERRQUEUE David Carlier
2026-04-21 16:07 ` [PATCH 0/3] mptcp: add RECVERR and MSG_ERRQUEUE support Matthieu Baerts
2026-04-21 17:16 ` David CARLIER
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