From: Stanislav Fomichev <sdf@google.com>
Date: Fri, 8 May 2020 10:46:10 -0700
Subject: net: Refactor arguments of inet{,6}_bind
Patch-mainline: v5.8-rc1
Git-commit: cb0721c7e200750907bb8ef59b12646a5cb2dadf
References: bsc#1177028

The intent is to add an additional bind parameter in the next commit.
Instead of adding another argument, let's convert all existing
flag arguments into an extendable bit field.

No functional changes.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200508174611.228805-4-sdf@google.com
Acked-by: Gary Lin <glin@suse.com>
---
 include/net/inet_common.h |    6 +++++-
 include/net/ipv6_stubs.h  |    2 +-
 net/core/filter.c         |    6 ++++--
 net/ipv4/af_inet.c        |   10 +++++-----
 net/ipv6/af_inet6.c       |   10 +++++-----
 5 files changed, 20 insertions(+), 14 deletions(-)

--- a/include/net/inet_common.h
+++ b/include/net/inet_common.h
@@ -35,8 +35,12 @@ int inet_shutdown(struct socket *sock, i
 int inet_listen(struct socket *sock, int backlog);
 void inet_sock_destruct(struct sock *sk);
 int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len);
+/* Don't allocate port at this moment, defer to connect. */
+#define BIND_FORCE_ADDRESS_NO_PORT	(1 << 0)
+/* Grab and release socket lock. */
+#define BIND_WITH_LOCK			(1 << 1)
 int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
-		bool force_bind_address_no_port, bool with_lock);
+		u32 flags);
 int inet_getname(struct socket *sock, struct sockaddr *uaddr,
 		 int peer);
 int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
--- a/include/net/ipv6_stubs.h
+++ b/include/net/ipv6_stubs.h
@@ -63,7 +63,7 @@ extern const struct ipv6_stub *ipv6_stub
 /* A stub used by bpf helpers. Similarly ugly as ipv6_stub */
 struct ipv6_bpf_stub {
 	int (*inet6_bind)(struct sock *sk, struct sockaddr *uaddr, int addr_len,
-			  bool force_bind_address_no_port, bool with_lock);
+			  u32 flags);
 	struct sock *(*udp6_lib_lookup)(struct net *net,
 				     const struct in6_addr *saddr, __be16 sport,
 				     const struct in6_addr *daddr, __be16 dport,
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4538,7 +4538,8 @@ BPF_CALL_3(bpf_bind, struct bpf_sock_add
 			return err;
 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
 			return err;
-		return __inet_bind(sk, addr, addr_len, true, false);
+		return __inet_bind(sk, addr, addr_len,
+				   BIND_FORCE_ADDRESS_NO_PORT);
 #if IS_ENABLED(CONFIG_IPV6)
 	} else if (addr->sa_family == AF_INET6) {
 		if (addr_len < SIN6_LEN_RFC2133)
@@ -4548,7 +4549,8 @@ BPF_CALL_3(bpf_bind, struct bpf_sock_add
 		/* ipv6_bpf_stub cannot be NULL, since it's called from
 		 * bpf_cgroup_inet6_connect hook and ipv6 is already loaded
 		 */
-		return ipv6_bpf_stub->inet6_bind(sk, addr, addr_len, true, false);
+		return ipv6_bpf_stub->inet6_bind(sk, addr, addr_len,
+						 BIND_FORCE_ADDRESS_NO_PORT);
 #endif /* CONFIG_IPV6 */
 	}
 #endif /* CONFIG_INET */
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -450,12 +450,12 @@ int inet_bind(struct socket *sock, struc
 	if (err)
 		return err;
 
-	return __inet_bind(sk, uaddr, addr_len, false, true);
+	return __inet_bind(sk, uaddr, addr_len, BIND_WITH_LOCK);
 }
 EXPORT_SYMBOL(inet_bind);
 
 int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
-		bool force_bind_address_no_port, bool with_lock)
+		u32 flags)
 {
 	struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
 	struct inet_sock *inet = inet_sk(sk);
@@ -506,7 +506,7 @@ int __inet_bind(struct sock *sk, struct
 	 *      would be illegal to use them (multicast/broadcast) in
 	 *      which case the sending device address is used.
 	 */
-	if (with_lock)
+	if (flags & BIND_WITH_LOCK)
 		lock_sock(sk);
 
 	/* Check these errors (active socket, double bind). */
@@ -520,7 +520,7 @@ int __inet_bind(struct sock *sk, struct
 
 	/* Make sure we are allowed to bind here. */
 	if (snum || !(inet->bind_address_no_port ||
-		      force_bind_address_no_port)) {
+		      (flags & BIND_FORCE_ADDRESS_NO_PORT))) {
 		if (sk->sk_prot->get_port(sk, snum)) {
 			inet->inet_saddr = inet->inet_rcv_saddr = 0;
 			err = -EADDRINUSE;
@@ -543,7 +543,7 @@ int __inet_bind(struct sock *sk, struct
 	sk_dst_reset(sk);
 	err = 0;
 out_release_sock:
-	if (with_lock)
+	if (flags & BIND_WITH_LOCK)
 		release_sock(sk);
 out:
 	return err;
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -273,7 +273,7 @@ out_rcu_unlock:
 }
 
 static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
-			bool force_bind_address_no_port, bool with_lock)
+			u32 flags)
 {
 	struct sockaddr_in6 *addr = (struct sockaddr_in6 *)uaddr;
 	struct inet_sock *inet = inet_sk(sk);
@@ -297,7 +297,7 @@ static int __inet6_bind(struct sock *sk,
 	    !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
 		return -EACCES;
 
-	if (with_lock)
+	if (flags & BIND_WITH_LOCK)
 		lock_sock(sk);
 
 	/* Check these errors (active socket, double bind). */
@@ -400,7 +400,7 @@ static int __inet6_bind(struct sock *sk,
 
 	/* Make sure we are allowed to bind here. */
 	if (snum || !(inet->bind_address_no_port ||
-		      force_bind_address_no_port)) {
+		      (flags & BIND_FORCE_ADDRESS_NO_PORT))) {
 		if (sk->sk_prot->get_port(sk, snum)) {
 			sk->sk_ipv6only = saved_ipv6only;
 			inet_reset_saddr(sk);
@@ -423,7 +423,7 @@ static int __inet6_bind(struct sock *sk,
 	inet->inet_dport = 0;
 	inet->inet_daddr = 0;
 out:
-	if (with_lock)
+	if (flags & BIND_WITH_LOCK)
 		release_sock(sk);
 	return err;
 out_unlock:
@@ -451,7 +451,7 @@ int inet6_bind(struct socket *sock, stru
 	if (err)
 		return err;
 
-	return __inet6_bind(sk, uaddr, addr_len, false, true);
+	return __inet6_bind(sk, uaddr, addr_len, BIND_WITH_LOCK);
 }
 EXPORT_SYMBOL(inet6_bind);