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Message-ID: <20230921133021.1995349-4-edumazet@google.com>
Date: Thu, 21 Sep 2023 13:30:16 +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 3/8] inet: implement lockless IP_TOS
Some reads of inet->tos are racy.
Add needed READ_ONCE() annotations and convert IP_TOS option lockless.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
include/net/ip.h | 1 -
net/dccp/ipv4.c | 2 +-
net/ipv4/inet_diag.c | 2 +-
net/ipv4/ip_output.c | 4 +--
net/ipv4/ip_sockglue.c | 29 ++++++++-----------
net/ipv4/tcp_ipv4.c | 9 +++---
net/mptcp/sockopt.c | 8 ++---
net/sctp/protocol.c | 4 +--
.../selftests/net/mptcp/mptcp_connect.sh | 2 +-
9 files changed, 28 insertions(+), 33 deletions(-)
diff --git a/include/net/ip.h b/include/net/ip.h
index 46933a0d98eac2db40c2e88006125588b8f8143e..8836ee5502669f6d3a5fc35a045695bac1c3b1a9 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -810,6 +810,5 @@ 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/dccp/ipv4.c b/net/dccp/ipv4.c
index 8f56e8723c7386c9f9344f1376823bfd0077c8c2..ef55e4c99e5109d68da5016e5c30e01fa50722be 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -516,7 +516,7 @@ static int dccp_v4_send_response(const struct sock *sk, struct request_sock *req
err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
ireq->ir_rmt_addr,
rcu_dereference(ireq->ireq_opt),
- inet_sk(sk)->tos);
+ READ_ONCE(inet_sk(sk)->tos));
rcu_read_unlock();
err = net_xmit_eval(err);
}
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index e13a84433413ed88088435ff8e11efeb30fc3cca..1f2d7a8bd060e59baeb00fcb1c6aabfcb3bb213d 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -134,7 +134,7 @@ int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
* hence this needs to be included regardless of socket family.
*/
if (ext & (1 << (INET_DIAG_TOS - 1)))
- if (nla_put_u8(skb, INET_DIAG_TOS, inet->tos) < 0)
+ if (nla_put_u8(skb, INET_DIAG_TOS, READ_ONCE(inet->tos)) < 0)
goto errout;
#if IS_ENABLED(CONFIG_IPV6)
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 2be281f184a5fe5a695ccd51fabe69fa45bea0b8..85320f92e8363d59e92c54139044cbab7e0561fa 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -544,7 +544,7 @@ EXPORT_SYMBOL(__ip_queue_xmit);
int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)
{
- return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos);
+ return __ip_queue_xmit(sk, skb, fl, READ_ONCE(inet_sk(sk)->tos));
}
EXPORT_SYMBOL(ip_queue_xmit);
@@ -1438,7 +1438,7 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
iph = ip_hdr(skb);
iph->version = 4;
iph->ihl = 5;
- iph->tos = (cork->tos != -1) ? cork->tos : inet->tos;
+ iph->tos = (cork->tos != -1) ? cork->tos : READ_ONCE(inet->tos);
iph->frag_off = df;
iph->ttl = ttl;
iph->protocol = sk->sk_protocol;
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 6d874cc03c8b4e88d79ebc50a6db105606b6ae60..50c008efbb6de7303621dd30b178c90cb3f5a2fc 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -585,25 +585,20 @@ int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
return err;
}
-void __ip_sock_set_tos(struct sock *sk, int val)
+void ip_sock_set_tos(struct sock *sk, int val)
{
+ u8 old_tos = READ_ONCE(inet_sk(sk)->tos);
+
if (sk->sk_type == SOCK_STREAM) {
val &= ~INET_ECN_MASK;
- val |= inet_sk(sk)->tos & INET_ECN_MASK;
+ val |= old_tos & INET_ECN_MASK;
}
- if (inet_sk(sk)->tos != val) {
- inet_sk(sk)->tos = val;
+ if (old_tos != val) {
+ WRITE_ONCE(inet_sk(sk)->tos, val);
WRITE_ONCE(sk->sk_priority, rt_tos2priority(val));
sk_dst_reset(sk);
}
}
-
-void ip_sock_set_tos(struct sock *sk, int val)
-{
- lock_sock(sk);
- __ip_sock_set_tos(sk, val);
- release_sock(sk);
-}
EXPORT_SYMBOL(ip_sock_set_tos);
void ip_sock_set_freebind(struct sock *sk)
@@ -1050,6 +1045,9 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
return 0;
case IP_MTU_DISCOVER:
return ip_sock_set_mtu_discover(sk, val);
+ case IP_TOS: /* This sets both TOS and Precedence */
+ ip_sock_set_tos(sk, val);
+ return 0;
}
err = 0;
@@ -1104,9 +1102,6 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
}
}
break;
- case IP_TOS: /* This sets both TOS and Precedence */
- __ip_sock_set_tos(sk, val);
- break;
case IP_UNICAST_IF:
{
struct net_device *dev = NULL;
@@ -1593,6 +1588,9 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
case IP_MTU_DISCOVER:
val = READ_ONCE(inet->pmtudisc);
goto copyval;
+ case IP_TOS:
+ val = READ_ONCE(inet->tos);
+ goto copyval;
}
if (needs_rtnl)
@@ -1629,9 +1627,6 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
return -EFAULT;
return 0;
}
- case IP_TOS:
- val = inet->tos;
- break;
case IP_MTU:
{
struct dst_entry *dst;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index f13eb7e23d03f3681055257e6ebea0612ae3f9b3..1f89ba58e71eff74d8ed75019de9e70d2f4d5926 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1024,10 +1024,11 @@ static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
if (skb) {
__tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
- tos = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) ?
- (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
- (inet_sk(sk)->tos & INET_ECN_MASK) :
- inet_sk(sk)->tos;
+ tos = READ_ONCE(inet_sk(sk)->tos);
+
+ if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos))
+ tos = (tcp_rsk(req)->syn_tos & ~INET_ECN_MASK) |
+ (tos & INET_ECN_MASK);
if (!INET_ECN_is_capable(tos) &&
tcp_bpf_ca_needs_ecn((struct sock *)req))
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 8260202c00669fd7d2eed2f94a3c2cf225a0d89c..155e8472ba9b83c35c6f827b2bb35c0be4127917 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -734,11 +734,11 @@ static int mptcp_setsockopt_v4_set_tos(struct mptcp_sock *msk, int optname,
lock_sock(sk);
sockopt_seq_inc(msk);
- val = inet_sk(sk)->tos;
+ val = READ_ONCE(inet_sk(sk)->tos);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
- __ip_sock_set_tos(ssk, val);
+ ip_sock_set_tos(ssk, val);
}
release_sock(sk);
@@ -1343,7 +1343,7 @@ static int mptcp_getsockopt_v4(struct mptcp_sock *msk, int optname,
switch (optname) {
case IP_TOS:
- return mptcp_put_int_option(msk, optval, optlen, inet_sk(sk)->tos);
+ return mptcp_put_int_option(msk, optval, optlen, READ_ONCE(inet_sk(sk)->tos));
}
return -EOPNOTSUPP;
@@ -1411,7 +1411,7 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
ssk->sk_bound_dev_if = sk->sk_bound_dev_if;
ssk->sk_incoming_cpu = sk->sk_incoming_cpu;
ssk->sk_ipv6only = sk->sk_ipv6only;
- __ip_sock_set_tos(ssk, inet_sk(sk)->tos);
+ 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;
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 2185f44198deb002bc8ed7f1b0f3fe02d6bb9f09..94c6dd53cd62d1fa6236d07946e8d5ff68eb587d 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -426,7 +426,7 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
struct dst_entry *dst = NULL;
union sctp_addr *daddr = &t->ipaddr;
union sctp_addr dst_saddr;
- __u8 tos = inet_sk(sk)->tos;
+ u8 tos = READ_ONCE(inet_sk(sk)->tos);
if (t->dscp & SCTP_DSCP_SET_MASK)
tos = t->dscp & SCTP_DSCP_VAL_MASK;
@@ -1057,7 +1057,7 @@ static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t)
struct flowi4 *fl4 = &t->fl.u.ip4;
struct sock *sk = skb->sk;
struct inet_sock *inet = inet_sk(sk);
- __u8 dscp = inet->tos;
+ __u8 dscp = READ_ONCE(inet->tos);
__be16 df = 0;
pr_debug("%s: skb:%p, len:%d, src:%pI4, dst:%pI4\n", __func__, skb,
diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.sh b/tools/testing/selftests/net/mptcp/mptcp_connect.sh
index b1fc8afd072dc6ddde8d561a675a5549a9a37dba..61a2a1988ce69ffa17e0dd8e629eac550f4f7d99 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_connect.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_connect.sh
@@ -716,7 +716,7 @@ run_test_transparent()
# the required infrastructure in MPTCP sockopt code. To support TOS, the
# following function has been exported (T). Not great but better than
# checking for a specific kernel version.
- if ! mptcp_lib_kallsyms_has "T __ip_sock_set_tos$"; then
+ if ! mptcp_lib_kallsyms_has "T ip_sock_set_tos$"; then
echo "INFO: ${msg} not supported by the kernel: SKIP"
mptcp_lib_result_skip "${TEST_GROUP}"
return
--
2.42.0.459.ge4e396fd5e-goog
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