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Message-ID: <20230921133021.1995349-8-edumazet@google.com>
Date: Thu, 21 Sep 2023 13:30:20 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: David Ahern <dsahern@...nel.org>, netdev@...r.kernel.org, eric.dumazet@...il.com,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 7/8] inet: lockless IP_PKTOPTIONS implementation
Current implementation is already lockless, because the socket
lock is released before reading socket fields.
Add missing READ_ONCE() annotations.
Note that corresponding WRITE_ONCE() are needed, the order
of the patches do not really matter.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
net/ipv4/ip_sockglue.c | 76 ++++++++++++++++++++----------------------
1 file changed, 37 insertions(+), 39 deletions(-)
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 58995526c6e965d613b8cdea61b84916d608a6fb..1ee01ff64171c94b6b244589518a53ce807a212d 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1633,6 +1633,43 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
return -ENOTCONN;
goto copyval;
}
+ case IP_PKTOPTIONS:
+ {
+ struct msghdr msg;
+
+ if (sk->sk_type != SOCK_STREAM)
+ return -ENOPROTOOPT;
+
+ if (optval.is_kernel) {
+ msg.msg_control_is_user = false;
+ msg.msg_control = optval.kernel;
+ } else {
+ msg.msg_control_is_user = true;
+ msg.msg_control_user = optval.user;
+ }
+ msg.msg_controllen = len;
+ msg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0;
+
+ if (inet_test_bit(PKTINFO, sk)) {
+ struct in_pktinfo info;
+
+ info.ipi_addr.s_addr = READ_ONCE(inet->inet_rcv_saddr);
+ info.ipi_spec_dst.s_addr = READ_ONCE(inet->inet_rcv_saddr);
+ info.ipi_ifindex = READ_ONCE(inet->mc_index);
+ put_cmsg(&msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
+ }
+ if (inet_test_bit(TTL, sk)) {
+ int hlim = READ_ONCE(inet->mc_ttl);
+
+ put_cmsg(&msg, SOL_IP, IP_TTL, sizeof(hlim), &hlim);
+ }
+ if (inet_test_bit(TOS, sk)) {
+ int tos = READ_ONCE(inet->rcv_tos);
+ put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos);
+ }
+ len -= msg.msg_controllen;
+ return copy_to_sockptr(optlen, &len, sizeof(int));
+ }
case IP_UNICAST_IF:
val = (__force int)htonl((__u32) READ_ONCE(inet->uc_index));
goto copyval;
@@ -1678,45 +1715,6 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
else
err = ip_get_mcast_msfilter(sk, optval, optlen, len);
goto out;
- case IP_PKTOPTIONS:
- {
- struct msghdr msg;
-
- sockopt_release_sock(sk);
-
- if (sk->sk_type != SOCK_STREAM)
- return -ENOPROTOOPT;
-
- if (optval.is_kernel) {
- msg.msg_control_is_user = false;
- msg.msg_control = optval.kernel;
- } else {
- msg.msg_control_is_user = true;
- msg.msg_control_user = optval.user;
- }
- msg.msg_controllen = len;
- msg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0;
-
- if (inet_test_bit(PKTINFO, sk)) {
- struct in_pktinfo info;
-
- info.ipi_addr.s_addr = inet->inet_rcv_saddr;
- info.ipi_spec_dst.s_addr = inet->inet_rcv_saddr;
- info.ipi_ifindex = inet->mc_index;
- put_cmsg(&msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
- }
- if (inet_test_bit(TTL, sk)) {
- int hlim = READ_ONCE(inet->mc_ttl);
-
- put_cmsg(&msg, SOL_IP, IP_TTL, sizeof(hlim), &hlim);
- }
- if (inet_test_bit(TOS, sk)) {
- int tos = inet->rcv_tos;
- put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos);
- }
- len -= msg.msg_controllen;
- return copy_to_sockptr(optlen, &len, sizeof(int));
- }
case IP_LOCAL_PORT_RANGE:
val = inet->local_port_range.hi << 16 | inet->local_port_range.lo;
break;
--
2.42.0.459.ge4e396fd5e-goog
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