ipv6: lockless IPV6_RECVERR implemetation

np->recverr is moved to inet->inet_flags to fix data-races.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 19 insertions, 22 deletions

diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index e81892814935..74673a5eff31 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -305,11 +305,10 @@ static void ipv6_icmp_error_rfc4884(const struct sk_buff *skb,
 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 		     __be16 port, u32 info, u8 *payload)
 {
-	struct ipv6_pinfo *np  = inet6_sk(sk);
 	struct icmp6hdr *icmph = icmp6_hdr(skb);
 	struct sock_exterr_skb *serr;
 
-	if (!np->recverr)
+	if (!inet6_test_bit(RECVERR6, sk))
 		return;
 
 	skb = skb_clone(skb, GFP_ATOMIC);
@@ -344,12 +343,11 @@ EXPORT_SYMBOL_GPL(ipv6_icmp_error);
 
 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
 {
-	const struct ipv6_pinfo *np = inet6_sk(sk);
 	struct sock_exterr_skb *serr;
 	struct ipv6hdr *iph;
 	struct sk_buff *skb;
 
-	if (!np->recverr)
+	if (!inet6_test_bit(RECVERR6, sk))
 		return;
 
 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 33dd4dd872e6..ec10b45c49c1 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -481,6 +481,13 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 	case IPV6_DONTFRAG:
 		inet6_assign_bit(DONTFRAG, sk, valbool);
 		return 0;
+	case IPV6_RECVERR:
+		if (optlen < sizeof(int))
+			return -EINVAL;
+		inet6_assign_bit(RECVERR6, sk, valbool);
+		if (!val)
+			skb_errqueue_purge(&sk->sk_error_queue);
+		return 0;
 	}
 	if (needs_rtnl)
 		rtnl_lock();
@@ -943,14 +950,6 @@ done:
 		np->pmtudisc = val;
 		retv = 0;
 		break;
-	case IPV6_RECVERR:
-		if (optlen < sizeof(int))
-			goto e_inval;
-		np->recverr = valbool;
-		if (!val)
-			skb_errqueue_purge(&sk->sk_error_queue);
-		retv = 0;
-		break;
 	case IPV6_FLOWINFO_SEND:
 		if (optlen < sizeof(int))
 			goto e_inval;
@@ -1380,7 +1379,7 @@ int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
 		break;
 
 	case IPV6_RECVERR:
-		val = np->recverr;
+		val = inet6_test_bit(RECVERR6, sk);
 		break;
 
 	case IPV6_FLOWINFO_SEND:
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index cc9673c1809f..71f6bdccfa1f 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -291,6 +291,7 @@ static void rawv6_err(struct sock *sk, struct sk_buff *skb,
 	       struct inet6_skb_parm *opt,
 	       u8 type, u8 code, int offset, __be32 info)
 {
+	bool recverr = inet6_test_bit(RECVERR6, sk);
 	struct ipv6_pinfo *np = inet6_sk(sk);
 	int err;
 	int harderr;
@@ -300,7 +301,7 @@ static void rawv6_err(struct sock *sk, struct sk_buff *skb,
 	   2. Socket is connected (otherwise the error indication
 	      is useless without recverr and error is hard.
 	 */
-	if (!np->recverr && sk->sk_state != TCP_ESTABLISHED)
+	if (!recverr && sk->sk_state != TCP_ESTABLISHED)
 		return;
 
 	harderr = icmpv6_err_convert(type, code, &err);
@@ -312,14 +313,14 @@ static void rawv6_err(struct sock *sk, struct sk_buff *skb,
 		ip6_sk_redirect(skb, sk);
 		return;
 	}
-	if (np->recverr) {
+	if (recverr) {
 		u8 *payload = skb->data;
 		if (!inet_test_bit(HDRINCL, sk))
 			payload += offset;
 		ipv6_icmp_error(sk, skb, err, 0, ntohl(info), payload);
 	}
 
-	if (np->recverr || harderr) {
+	if (recverr || harderr) {
 		sk->sk_err = err;
 		sk_error_report(sk);
 	}
@@ -587,7 +588,6 @@ static int rawv6_send_hdrinc(struct sock *sk, struct msghdr *msg, int length,
 			struct flowi6 *fl6, struct dst_entry **dstp,
 			unsigned int flags, const struct sockcm_cookie *sockc)
 {
-	struct ipv6_pinfo *np = inet6_sk(sk);
 	struct net *net = sock_net(sk);
 	struct ipv6hdr *iph;
 	struct sk_buff *skb;
@@ -668,7 +668,7 @@ out:
 error:
 	IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
 error_check:
-	if (err == -ENOBUFS && !np->recverr)
+	if (err == -ENOBUFS && !inet6_test_bit(RECVERR6, sk))
 		err = 0;
 	return err;
 }
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 54db5fab318b..b5954b136b57 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -508,7 +508,7 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 			tcp_ld_RTO_revert(sk, seq);
 	}
 
-	if (!sock_owned_by_user(sk) && np->recverr) {
+	if (!sock_owned_by_user(sk) && inet6_test_bit(RECVERR6, sk)) {
 		WRITE_ONCE(sk->sk_err, err);
 		sk_error_report(sk);
 	} else {
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index e4301500741a..90e873689b88 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -619,7 +619,7 @@ int __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		goto out;
 	}
 
-	if (!np->recverr) {
+	if (!inet6_test_bit(RECVERR6, sk)) {
 		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 			goto out;
 	} else {
@@ -1283,7 +1283,7 @@ csum_partial:
 send:
 	err = ip6_send_skb(skb);
 	if (err) {
-		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
+		if (err == -ENOBUFS && !inet6_test_bit(RECVERR6, sk)) {
 			UDP6_INC_STATS(sock_net(sk),
 				       UDP_MIB_SNDBUFERRORS, is_udplite);
 			err = 0;
@@ -1608,7 +1608,7 @@ do_append_data:
 		up->pending = 0;
 
 	if (err > 0)
-		err = np->recverr ? net_xmit_errno(err) : 0;
+		err = inet6_test_bit(RECVERR6, sk) ? net_xmit_errno(err) : 0;
 	release_sock(sk);
 
 out: