netdev - [net-next RFC 4/4] bindtosubnet: UPD implementation

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Message-Id: <1458134349-2454-5-git-send-email-gilberto.bertin@gmail.com>
Date:	Wed, 16 Mar 2016 13:19:09 +0000
From:	Gilberto Bertin <gilberto.bertin@...il.com>
To:	netdev@...r.kernel.org
Cc:	Gilberto Bertin <gilberto.bertin@...il.com>
Subject: [net-next RFC 4/4] bindtosubnet: UPD implementation

Signed-off-by: Gilberto Bertin <gilberto.bertin@...il.com>
---
 net/ipv4/udp.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 95d2f19..1ecffa8 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -133,6 +133,23 @@ EXPORT_SYMBOL(udp_memory_allocated);
 #define MAX_UDP_PORTS 65536
 #define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
 
+static inline int udp_csk_bind_subnet_conflict(const struct sock *sk,
+					       const struct sock *sk2)
+{
+	__be32 mask;
+
+	if (sk->sk_bind_to_subnet && sk2->sk_bind_to_subnet) {
+		mask = inet_make_mask(min(sk->sk_bind_subnet4.plen,
+					  sk2->sk_bind_subnet4.plen));
+
+		return (sk->sk_bind_subnet4.net & mask) ==
+		       (sk2->sk_bind_subnet4.net & mask);
+	}
+
+	return 0;
+}
+
+
 static int udp_lib_lport_inuse(struct net *net, __u16 num,
 			       const struct udp_hslot *hslot,
 			       unsigned long *bitmap,
@@ -153,6 +170,7 @@ static int udp_lib_lport_inuse(struct net *net, __u16 num,
 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
+		     udp_csk_bind_subnet_conflict(sk, sk2) &&
 		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
 		     rcu_access_pointer(sk->sk_reuseport_cb) ||
 		     !uid_eq(uid, sock_i_uid(sk2))) &&
@@ -189,6 +207,7 @@ static int udp_lib_lport_inuse2(struct net *net, __u16 num,
 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
+		     udp_csk_bind_subnet_conflict(sk, sk2) &&
 		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
 		     rcu_access_pointer(sk->sk_reuseport_cb) ||
 		     !uid_eq(uid, sock_i_uid(sk2))) &&
@@ -426,6 +445,15 @@ static inline int compute_score(struct sock *sk, struct net *net,
 			return -1;
 		score += 4;
 	}
+
+	if (sk->sk_bind_to_subnet) {
+		__be32 mask = inet_make_mask(sk->sk_bind_subnet4.plen);
+
+		if ((sk->sk_bind_subnet4.net & mask) != (daddr & mask))
+			return -1;
+		score += 4;
+	}
+
 	if (sk->sk_incoming_cpu == raw_smp_processor_id())
 		score++;
 	return score;
@@ -471,6 +499,14 @@ static inline int compute_score2(struct sock *sk, struct net *net,
 		score += 4;
 	}
 
+	if (sk->sk_bind_to_subnet) {
+		__be32 mask = inet_make_mask(sk->sk_bind_subnet4.plen);
+
+		if ((sk->sk_bind_subnet4.net & mask) != (daddr & mask))
+			return -1;
+		score += 4;
+	}
+
 	if (sk->sk_incoming_cpu == raw_smp_processor_id())
 		score++;
 
-- 
2.7.2