[RFCv2 bpf-next 09/12] udp6: Run inet_lookup bpf program on socket lookup

[Jakub Sitnicki <jakub@cloudflare.com>]

Same as for udp, split the socket lookup into two phases and let the BPF
inet_lookup program select the receiving socket.

Suggested-by: Marek Majkowski <marek@cloudflare.com>
Reviewed-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---
 net/ipv6/udp.c | 42 ++++++++++++++++++++++++++++++------------
 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 16ef2303bd8d..7380cf57e88c 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -101,7 +101,7 @@ void udp_v6_rehash(struct sock *sk)
 static int compute_score(struct sock *sk, struct net *net,
 			 const struct in6_addr *saddr, __be16 sport,
 			 const struct in6_addr *daddr, unsigned short hnum,
-			 int dif, int sdif)
+			 int dif, int sdif, unsigned char state)
 {
 	int score;
 	struct inet_sock *inet;
@@ -112,6 +112,9 @@ static int compute_score(struct sock *sk, struct net *net,
 	    sk->sk_family != PF_INET6)
 		return -1;
 
+	if (state && sk->sk_state != state)
+		return -1;
+
 	if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
 		return -1;
 
@@ -146,7 +149,7 @@ static struct sock *udp6_lib_lookup2(struct net *net,
 		const struct in6_addr *saddr, __be16 sport,
 		const struct in6_addr *daddr, unsigned int hnum,
 		int dif, int sdif, struct udp_hslot *hslot2,
-		struct sk_buff *skb)
+		struct sk_buff *skb, unsigned char state)
 {
 	struct sock *sk, *result;
 	int score, badness;
@@ -156,7 +159,7 @@ static struct sock *udp6_lib_lookup2(struct net *net,
 	badness = -1;
 	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
 		score = compute_score(sk, net, saddr, sport,
-				      daddr, hnum, dif, sdif);
+				      daddr, hnum, dif, sdif, state);
 		if (score > badness) {
 			if (sk->sk_reuseport) {
 				hash = udp6_ehashfn(net, daddr, hnum,
@@ -190,19 +193,34 @@ struct sock *__udp6_lib_lookup(struct net *net,
 	slot2 = hash2 & udptable->mask;
 	hslot2 = &udptable->hash2[slot2];
 
+	/* Lookup connected sockets */
 	result = udp6_lib_lookup2(net, saddr, sport,
 				  daddr, hnum, dif, sdif,
-				  hslot2, skb);
-	if (!result) {
-		hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
-		slot2 = hash2 & udptable->mask;
+				  hslot2, skb, TCP_ESTABLISHED);
+	if (result)
+		goto done;
 
-		hslot2 = &udptable->hash2[slot2];
+	/* Lookup redirect from BPF */
+	result = inet6_lookup_run_bpf(net, udptable->protocol,
+				      saddr, sport, daddr, hnum);
+	if (result)
+		goto done;
 
-		result = udp6_lib_lookup2(net, saddr, sport,
-					  &in6addr_any, hnum, dif, sdif,
-					  hslot2, skb);
-	}
+	/* Lookup bound sockets */
+	result = udp6_lib_lookup2(net, saddr, sport,
+				  daddr, hnum, dif, sdif,
+				  hslot2, skb, 0);
+	if (result)
+		goto done;
+
+	hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
+	slot2 = hash2 & udptable->mask;
+	hslot2 = &udptable->hash2[slot2];
+
+	result = udp6_lib_lookup2(net, saddr, sport,
+				  &in6addr_any, hnum, dif, sdif,
+				  hslot2, skb, 0);
+done:
 	if (IS_ERR(result))
 		return NULL;
 	return result;
-- 
2.20.1