[PATCH v2 net-next] net: Deprecate SO_DEBUG and reclaim SOCK_DBG bit.

Kuniyuki Iwashima
2024-02-14T19:54:22Z

Recently, commit 8e5443d2b866 ("net: remove SOCK_DEBUG leftovers")
removed the last users of SOCK_DEBUG(), and commit b1dffcf0da22 ("net:
remove SOCK_DEBUG macro") removed the macro.

Now is the time to deprecate the oldest socket option.

Note that setsockopt(SO_DEBUG) is moved not to acquire lock_sock().

Reviewed-by: Gerd Bayer <gbayer@linux.ibm.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
v2:
* Move setsockopt(SO_DEBUG) code not to acquire lock_sock().

v1: https://lore.kernel.org/netdev/20240213223135.85957-1-kuniyu@amazon.com/
---
include/net/sock.h | 1 -
net/core/sock.c | 14 +++++++-------
net/mptcp/sockopt.c | 8 +-------
net/smc/af_smc.c | 5 ++---
4 files changed, 10 insertions(+), 18 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index a9d99a9c583f..e20d55a36f9c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -909,7 +909,6 @@ enum sock_flags {
SOCK_TIMESTAMP,
SOCK_ZAPPED,
SOCK_USE_WRITE_QUEUE, /* whether to call sk->sk_write_space in sock_wfree */
- SOCK_DBG, /* %SO_DEBUG setting */
SOCK_RCVTSTAMP, /* %SO_TIMESTAMP setting */
SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
diff --git a/net/core/sock.c b/net/core/sock.c
index 88bf810394a5..c4c406f4742e 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1115,6 +1115,11 @@ int sk_setsockopt(struct sock *sk, int level, int optname,

/* handle options which do not require locking the socket. */
switch (optname) {
+ case SO_DEBUG:
+ /* deprecated, but kept for compatibility */
+ if (val && !sockopt_capable(CAP_NET_ADMIN))
+ ret = -EACCES;
+ return 0;
case SO_PRIORITY:
if ((val >= 0 && val <= 6) ||
sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_RAW) ||
@@ -1193,12 +1198,6 @@ int sk_setsockopt(struct sock *sk, int level, int optname,
sockopt_lock_sock(sk);

switch (optname) {
- case SO_DEBUG:
- if (val && !sockopt_capable(CAP_NET_ADMIN))
- ret = -EACCES;
- else
- sock_valbool_flag(sk, SOCK_DBG, valbool);
- break;
case SO_REUSEADDR:
sk->sk_reuse = (valbool ? SK_CAN_REUSE : SK_NO_REUSE);
break;
@@ -1619,7 +1618,8 @@ int sk_getsockopt(struct sock *sk, int level, int optname,

switch (optname) {
case SO_DEBUG:
- v.val = sock_flag(sk, SOCK_DBG);
+ /* deprecated. */
+ v.val = 0;
break;

case SO_DONTROUTE:
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index da37e4541a5d..31d09009332a 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -80,9 +80,6 @@ static void mptcp_sol_socket_sync_intval(struct mptcp_sock *msk, int optname, in
bool slow = lock_sock_fast(ssk);

switch (optname) {
- case SO_DEBUG:
- sock_valbool_flag(ssk, SOCK_DBG, !!val);
- break;
case SO_KEEPALIVE:
if (ssk->sk_prot->keepalive)
ssk->sk_prot->keepalive(ssk, !!val);
@@ -183,7 +180,6 @@ static int mptcp_setsockopt_sol_socket_int(struct mptcp_sock *msk, int optname,
case SO_KEEPALIVE:
mptcp_sol_socket_sync_intval(msk, optname, val);
return 0;
- case SO_DEBUG:
case SO_MARK:
case SO_PRIORITY:
case SO_SNDBUF:
@@ -329,7 +325,6 @@ static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
case SO_RCVBUFFORCE:
case SO_MARK:
case SO_INCOMING_CPU:
- case SO_DEBUG:
case SO_TIMESTAMP_OLD:
case SO_TIMESTAMP_NEW:
case SO_TIMESTAMPNS_OLD:
@@ -363,6 +358,7 @@ static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname,
case SO_WIFI_STATUS:
case SO_NOFCS:
case SO_SELECT_ERR_QUEUE:
+ case SO_DEBUG: /* deprecated */
return 0;
}

@@ -1458,8 +1454,6 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
sk_dst_reset(ssk);
}

- sock_valbool_flag(ssk, SOCK_DBG, sock_flag(sk, SOCK_DBG));
-
if (inet_csk(sk)->icsk_ca_ops != inet_csk(ssk)->icsk_ca_ops)
tcp_set_congestion_control(ssk, msk->ca_name, false, true);
__tcp_sock_set_cork(ssk, !!msk->cork);
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 66763c74ab76..062e16a2766a 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -445,7 +445,6 @@ static int smc_bind(struct socket *sock, struct sockaddr *uaddr,
(1UL << SOCK_LINGER) | \
(1UL << SOCK_BROADCAST) | \
(1UL << SOCK_TIMESTAMP) | \
- (1UL << SOCK_DBG) | \
(1UL << SOCK_RCVTSTAMP) | \
(1UL << SOCK_RCVTSTAMPNS) | \
(1UL << SOCK_LOCALROUTE) | \
@@ -511,8 +510,8 @@ static void smc_copy_sock_settings_to_clc(struct smc_sock *smc)

#define SK_FLAGS_CLC_TO_SMC ((1UL << SOCK_URGINLINE) | \
(1UL << SOCK_KEEPOPEN) | \
- (1UL << SOCK_LINGER) | \
- (1UL << SOCK_DBG))
+ (1UL << SOCK_LINGER))
+
/* copy only settings and flags relevant for smc from clc to smc socket */
static void smc_copy_sock_settings_to_smc(struct smc_sock *smc)
{
--
2.30.2