Commit 02715925 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

inet: implement lockless getsockopt(IP_MULTICAST_IF) 



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: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c4480eb5

net/ipv4/datagram.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

	}

net/ipv4/ip_sockglue.c

+12 −13
Original line number Diff line number Diff line
@@ -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;

net/ipv4/ping.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

net/ipv4/raw.c

+2 −2
Original line number Diff line number Diff line
@@ -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) {

net/ipv4/udp.c

+2 −2
Original line number Diff line number Diff line
@@ -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;