Re: [PATCH net-next v2 08/15] quic: add path management

+/* Lookup a quic_udp_sock in the global hash table. If not found, creates and returns a new one
+ * associated with the given kernel socket.
+ */
+static struct quic_udp_sock *quic_udp_sock_lookup(struct sock *sk, union quic_addr *a, u16 port)
+{
+	struct net *net = sock_net(sk);
+	struct quic_hash_head *head;
+	struct quic_udp_sock *us;
+
+	head = quic_udp_sock_head(net, port);
+	hlist_for_each_entry(us, &head->head, node) {
+		if (net != sock_net(us->sk))
+			continue;
+		if (a) {
+			if (quic_cmp_sk_addr(us->sk, &us->addr, a) &&
+			    (!us->bind_ifindex || !sk->sk_bound_dev_if ||
+			     us->bind_ifindex == sk->sk_bound_dev_if))
+				return us;
+			continue;
+		}
+		if (ntohs(us->addr.v4.sin_port) == port)
+			return us;
+	}
+	return NULL;
+}

+
+/* Binds a QUIC path to a local port and sets up a UDP socket. */
+int quic_path_bind(struct sock *sk, struct quic_path_group *paths, u8 path)
+{
+	union quic_addr *a = quic_path_saddr(paths, path);
+	int rover, low, high, remaining;
+	struct net *net = sock_net(sk);
+	struct quic_hash_head *head;
+	struct quic_udp_sock *us;
+	u16 port;
+
+	port = ntohs(a->v4.sin_port);
+	if (port) {
+		head = quic_udp_sock_head(net, port);
+		mutex_lock(&head->m_lock);
+		us = quic_udp_sock_lookup(sk, a, port);
+		if (!quic_udp_sock_get(us)) {
+			us = quic_udp_sock_create(sk, a);
+			if (!us) {
+				mutex_unlock(&head->m_lock);
+				return -EINVAL;
+			}
+		}
+		mutex_unlock(&head->m_lock);
+
+		quic_udp_sock_put(paths->path[path].udp_sk);
+		paths->path[path].udp_sk = us;
+		return 0;
+	}
+
+	inet_get_local_port_range(net, &low, &high);