[PATCH mptcp-next v3 0/2] Splitting commits for IP_TOS support in setsockopt()

[PATCH mptcp-next v3 0/2] Splitting commits for IP_TOS support in setsockopt()

[Poorva Sonparote]

- patch 1/2 Add Support for IP_TOS for MPTCP setsockopt()
- patch 2/2 Exposing  __ip_sock_set_tos() in ip.h


Poorva Sonparote (2):
  Exposing __ip_sock_set_tos() in ip.h
  Support for IP_TOS for MPTCP setsockopt()

 include/net/ip.h       |  1 +
 net/ipv4/ip_sockglue.c |  2 +-
 net/mptcp/sockopt.c    | 41 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 1 deletion(-)

-- 
2.18.2

[PATCH mptcp-next v3 1/2] Exposing __ip_sock_set_tos() in ip.h

[Poorva Sonparote]

Making the static function __ip_sock_set_tos() from net/ipv4/ip_sockglue.c
accessible by declaring it in include/net/ip.h
The reason for doing this is to use this function to set IP_TOS value in
mptcp_setsockopt() without the lock.

Signed-off-by: Poorva Sonparote <psonparo@redhat.com>
---
 include/net/ip.h       | 1 +
 net/ipv4/ip_sockglue.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/net/ip.h b/include/net/ip.h
index cf229a531194..3d65a3be10e7 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -789,5 +789,6 @@ int ip_sock_set_mtu_discover(struct sock *sk, int val);
 void ip_sock_set_pktinfo(struct sock *sk);
 void ip_sock_set_recverr(struct sock *sk);
 void ip_sock_set_tos(struct sock *sk, int val);
+void  __ip_sock_set_tos(struct sock *sk, int val);
 
 #endif	/* _IP_H */
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index b297bb28556e..7fd83f14daae 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -576,7 +576,7 @@ int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
 	return err;
 }
 
-static void __ip_sock_set_tos(struct sock *sk, int val)
+void __ip_sock_set_tos(struct sock *sk, int val)
 {
 	if (sk->sk_type == SOCK_STREAM) {
 		val &= ~INET_ECN_MASK;
-- 
2.18.2

[PATCH mptcp-next v3 2/2] Support for IP_TOS for MPTCP setsockopt()

[Poorva Sonparote]

SOL_IP provides a way to configure network layer attributes in a
socket. This patch adds support for IP_TOS for setsockopt(.. ,SOL_IP, ..)
https://github.com/multipath-tcp/mptcp_net-next/issues/220

Support for SOL_IP is added in mptcp_setsockopt() and IP_TOS is handled in
a private function. The idea here is to take in the value passed for IP_TOS
and set it to the current subflow, open subflows as well new subflows that
might be created after the initial call to setsockopt(). This sync is done
using sync_socket_options(.., ssk) and setting the value of tos using
 __ip_sock_set_tos(ssk,..).

The patch has been tested using the packetdrill script here -
https://github.com/multipath-tcp/mptcp_net-next/issues/220#issuecomment-947863717
It has not been selftested because there's no support for IP_TOS in
getsockopt() yet.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/220
Signed-off-by: Poorva Sonparote <psonparo@redhat.com>
---

Notes:
    - fixed formatting errors
    - split out the main patch into two commits
      1. Support for IP_TOS for MPTCP setsockopt()
      2. Exposing  __ip_sock_set_tos() in ip.h

 net/mptcp/sockopt.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 8137cc3a4296..ded47f0483ed 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -598,6 +598,43 @@ static int mptcp_setsockopt_sol_tcp_congestion(struct mptcp_sock *msk, sockptr_t
 	return ret;
 }
 
+static int mptcp_setsockopt_v4_set_tos(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, val;
+	int err;
+
+	err = ip_setsockopt(sk, SOL_IP, optname, optval, optlen);
+
+	if (err != 0)
+		return err;
+
+	lock_sock(sk);
+	sockopt_seq_inc(msk);
+	val = inet_sk(sk)->tos;
+	mptcp_for_each_subflow(msk, subflow) {
+		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+		__ip_sock_set_tos(ssk, val);
+	}
+	release_sock(sk);
+
+	return ret;
+}
+
+static int mptcp_setsockopt_v4(struct mptcp_sock *msk, int optname,
+			       sockptr_t optval, unsigned int optlen)
+{
+	switch (optname) {
+	case IP_TOS:
+		return mptcp_setsockopt_v4_set_tos(msk, optname, optval, optlen);
+	}
+
+	return -EOPNOTSUPP;
+}
+
 static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
 				    sockptr_t optval, unsigned int optlen)
 {
@@ -637,6 +674,9 @@ int mptcp_setsockopt(struct sock *sk, int level, int optname,
 	if (ssk)
 		return tcp_setsockopt(ssk, level, optname, optval, optlen);
 
+	if (level == SOL_IP)
+		return mptcp_setsockopt_v4(msk, optname, optval, optlen);
+
 	if (level == SOL_IPV6)
 		return mptcp_setsockopt_v6(msk, optname, optval, optlen);
 
@@ -1000,6 +1040,7 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
 	ssk->sk_priority = sk->sk_priority;
 	ssk->sk_bound_dev_if = sk->sk_bound_dev_if;
 	ssk->sk_incoming_cpu = sk->sk_incoming_cpu;
+	__ip_sock_set_tos(ssk, inet_sk(sk)->tos);
 
 	if (sk->sk_userlocks & tx_rx_locks) {
 		ssk->sk_userlocks |= sk->sk_userlocks & tx_rx_locks;
-- 
2.18.2