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inet: implement lockless IP_TOS

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Some reads of inet->tos are racy.

Add needed READ_ONCE() annotations and convert IP_TOS option lockless.

v2: missing changes in include/net/route.h (David Ahern)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2023-09-22 03:42:16 +00:00 committed by David S. Miller
parent ceaa714138
commit e08d0b3d17
10 changed files with 31 additions and 36 deletions
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3
include/net/ip.h
View file

@ -258,7 +258,7 @@ static inline u8 ip_sendmsg_scope(const struct inet_sock *inet,
static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
{
return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(READ_ONCE(inet->tos));
}
/* datagram.c */
@ -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 */

4
include/net/route.h
View file

@ -37,7 +37,7 @@
#define RTO_ONLINK 0x01
#define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
#define RT_CONN_FLAGS(sk) (RT_TOS(READ_ONCE(inet_sk(sk)->tos)) | sock_flag(sk, SOCK_LOCALROUTE))
#define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
static inline __u8 ip_sock_rt_scope(const struct sock *sk)
@ -50,7 +50,7 @@ static inline __u8 ip_sock_rt_scope(const struct sock *sk)
static inline __u8 ip_sock_rt_tos(const struct sock *sk)
{
return RT_TOS(inet_sk(sk)->tos);
return RT_TOS(READ_ONCE(inet_sk(sk)->tos));
}
struct ip_tunnel_info;

2
net/dccp/ipv4.c
View file

@ -511,7 +511,7 @@ 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);
}

2
net/ipv4/inet_diag.c
View file

@ -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)

4
net/ipv4/ip_output.c
View file

@ -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;

29
net/ipv4/ip_sockglue.c
View file

@ -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;

9
net/ipv4/tcp_ipv4.c
View file

@ -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))

8
net/mptcp/sockopt.c
View file

@ -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;

4
net/sctp/protocol.c
View file

@ -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,

2
tools/testing/selftests/net/mptcp/mptcp_connect.sh
View file

@ -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