+ unsigned int hash2_nulladdr =
+ udp4_portaddr_hash(sock_net(sk), INADDR_ANY, snum);
+ unsigned int hash2_partial =
+ udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
+
+ /* precompute partial secondary hash */
+ udp_sk(sk)->udp_portaddr_hash = hash2_partial;
+ return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
+}
+
+static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
+ unsigned short hnum,
+ __be16 sport, __be32 daddr, __be16 dport, int dif)
+{
+ int score = -1;
+
+ if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
+ !ipv6_only_sock(sk)) {
+ struct inet_sock *inet = inet_sk(sk);
+
+ score = (sk->sk_family == PF_INET ? 1 : 0);
+ if (inet->inet_rcv_saddr) {
+ if (inet->inet_rcv_saddr != daddr)
+ return -1;
+ score += 2;
+ }
+ if (inet->inet_daddr) {
+ if (inet->inet_daddr != saddr)
+ return -1;
+ score += 2;
+ }
+ if (inet->inet_dport) {
+ if (inet->inet_dport != sport)
+ return -1;
+ score += 2;
+ }
+ if (sk->sk_bound_dev_if) {
+ if (sk->sk_bound_dev_if != dif)
+ return -1;
+ score += 2;
+ }
+ }
+ return score;
+}
+
+/*
+ * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
+ */
+#define SCORE2_MAX (1 + 2 + 2 + 2)
+static inline int compute_score2(struct sock *sk, struct net *net,
+ __be32 saddr, __be16 sport,
+ __be32 daddr, unsigned int hnum, int dif)
+{
+ int score = -1;
+
+ if (net_eq(sock_net(sk), net) && !ipv6_only_sock(sk)) {
+ struct inet_sock *inet = inet_sk(sk);
+
+ if (inet->inet_rcv_saddr != daddr)
+ return -1;
+ if (inet->inet_num != hnum)
+ return -1;
+
+ score = (sk->sk_family == PF_INET ? 1 : 0);
+ if (inet->inet_daddr) {
+ if (inet->inet_daddr != saddr)
+ return -1;
+ score += 2;
+ }
+ if (inet->inet_dport) {
+ if (inet->inet_dport != sport)
+ return -1;
+ score += 2;
+ }
+ if (sk->sk_bound_dev_if) {
+ if (sk->sk_bound_dev_if != dif)
+ return -1;
+ score += 2;
+ }
+ }
+ return score;
+}
+
+
+/* called with read_rcu_lock() */
+static struct sock *udp4_lib_lookup2(struct net *net,
+ __be32 saddr, __be16 sport,
+ __be32 daddr, unsigned int hnum, int dif,
+ struct udp_hslot *hslot2, unsigned int slot2)
+{
+ struct sock *sk, *result;
+ struct hlist_nulls_node *node;
+ int score, badness;
+
+begin:
+ result = NULL;
+ badness = -1;
+ udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
+ score = compute_score2(sk, net, saddr, sport,
+ daddr, hnum, dif);
+ if (score > badness) {
+ result = sk;
+ badness = score;
+ if (score == SCORE2_MAX)
+ goto exact_match;
+ }
+ }
+ /*
+ * if the nulls value we got at the end of this lookup is
+ * not the expected one, we must restart lookup.
+ * We probably met an item that was moved to another chain.
+ */
+ if (get_nulls_value(node) != slot2)
+ goto begin;
+
+ if (result) {
+exact_match:
+ if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+ result = NULL;
+ else if (unlikely(compute_score2(result, net, saddr, sport,
+ daddr, hnum, dif) < badness)) {
+ sock_put(result);
+ goto begin;
+ }
+ }
+ return result;