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inet: implement lockless getsockopt(IP_MULTICAST_IF)

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Add missing annotations to inet->mc_index and inet->mc_addr
to fix data-races.

getsockopt(IP_MULTICAST_IF) can be lockless.

setsockopt() side is left for later.

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 03:42:21 +00:00 committed by David S. Miller
parent c4480eb550
commit 0271592522
5 changed files with 20 additions and 21 deletions
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4
net/ipv4/datagram.c
View file

@ -39,9 +39,9 @@ int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len
saddr = inet->inet_saddr;
if (ipv4_is_multicast(usin->sin_addr.s_addr)) {
if (!oif || netif_index_is_l3_master(sock_net(sk), oif))
oif = inet->mc_index;
oif = READ_ONCE(inet->mc_index);
if (!saddr)
saddr = inet->mc_addr;
saddr = READ_ONCE(inet->mc_addr);
} else if (!oif) {
oif = READ_ONCE(inet->uc_index);
}

25
net/ipv4/ip_sockglue.c
View file

@ -1168,8 +1168,8 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
if (!mreq.imr_ifindex) {
if (mreq.imr_address.s_addr == htonl(INADDR_ANY)) {
inet->mc_index = 0;
inet->mc_addr = 0;
WRITE_ONCE(inet->mc_index, 0);
WRITE_ONCE(inet->mc_addr, 0);
err = 0;
break;
}
@ -1194,8 +1194,8 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
midx != sk->sk_bound_dev_if)
break;
inet->mc_index = mreq.imr_ifindex;
inet->mc_addr = mreq.imr_address.s_addr;
WRITE_ONCE(inet->mc_index, mreq.imr_ifindex);
WRITE_ONCE(inet->mc_addr, mreq.imr_address.s_addr);
err = 0;
break;
}
@ -1673,19 +1673,11 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
case IP_UNICAST_IF:
val = (__force int)htonl((__u32) READ_ONCE(inet->uc_index));
goto copyval;
}
if (needs_rtnl)
rtnl_lock();
sockopt_lock_sock(sk);
switch (optname) {
case IP_MULTICAST_IF:
{
struct in_addr addr;
len = min_t(unsigned int, len, sizeof(struct in_addr));
addr.s_addr = inet->mc_addr;
sockopt_release_sock(sk);
addr.s_addr = READ_ONCE(inet->mc_addr);
if (copy_to_sockptr(optlen, &len, sizeof(int)))
return -EFAULT;
@ -1693,6 +1685,13 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
return -EFAULT;
return 0;
}
}
if (needs_rtnl)
rtnl_lock();
sockopt_lock_sock(sk);
switch (optname) {
case IP_MSFILTER:
{
struct ip_msfilter msf;

4
net/ipv4/ping.c
View file

@ -773,9 +773,9 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
if (ipv4_is_multicast(daddr)) {
if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
ipc.oif = inet->mc_index;
ipc.oif = READ_ONCE(inet->mc_index);
if (!saddr)
saddr = inet->mc_addr;
saddr = READ_ONCE(inet->mc_addr);
} else if (!ipc.oif)
ipc.oif = READ_ONCE(inet->uc_index);

4
net/ipv4/raw.c
View file

@ -579,9 +579,9 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
uc_index = READ_ONCE(inet->uc_index);
if (ipv4_is_multicast(daddr)) {
if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
ipc.oif = inet->mc_index;
ipc.oif = READ_ONCE(inet->mc_index);
if (!saddr)
saddr = inet->mc_addr;
saddr = READ_ONCE(inet->mc_addr);
} else if (!ipc.oif) {
ipc.oif = uc_index;
} else if (ipv4_is_lbcast(daddr) && uc_index) {

4
net/ipv4/udp.c
View file

@ -1177,9 +1177,9 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
uc_index = READ_ONCE(inet->uc_index);
if (ipv4_is_multicast(daddr)) {
if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
ipc.oif = inet->mc_index;
ipc.oif = READ_ONCE(inet->mc_index);
if (!saddr)
saddr = inet->mc_addr;
saddr = READ_ONCE(inet->mc_addr);
connected = 0;
} else if (!ipc.oif) {
ipc.oif = uc_index;