diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 5f04216f35ce..dd7f3d20989a 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -298,6 +298,91 @@ static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr, 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; +} + +#define udp_portaddr_for_each_entry_rcu(__sk, node, list) \ + hlist_nulls_for_each_entry_rcu(__sk, node, list, __sk_common.skc_portaddr_node) + +/* 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; +} + /* UDP is nearly always wildcards out the wazoo, it makes no sense to try * harder than this. -DaveM */ @@ -308,11 +393,35 @@ static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, struct sock *sk, *result; struct hlist_nulls_node *node; unsigned short hnum = ntohs(dport); - unsigned int hash = udp_hashfn(net, hnum, udptable->mask); - struct udp_hslot *hslot = &udptable->hash[hash]; + unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask); + struct udp_hslot *hslot2, *hslot = &udptable->hash[slot]; int score, badness; rcu_read_lock(); + if (hslot->count > 10) { + hash2 = udp4_portaddr_hash(net, daddr, hnum); + slot2 = hash2 & udptable->mask; + hslot2 = &udptable->hash2[slot2]; + if (hslot->count < hslot2->count) + goto begin; + + result = udp4_lib_lookup2(net, saddr, sport, + daddr, hnum, dif, + hslot2, slot2); + if (!result) { + hash2 = udp4_portaddr_hash(net, INADDR_ANY, hnum); + slot2 = hash2 & udptable->mask; + hslot2 = &udptable->hash2[slot2]; + if (hslot->count < hslot2->count) + goto begin; + + result = udp4_lib_lookup2(net, INADDR_ANY, sport, + daddr, hnum, dif, + hslot2, slot2); + } + rcu_read_unlock(); + return result; + } begin: result = NULL; badness = -1; @@ -329,7 +438,7 @@ begin: * not the expected one, we must restart lookup. * We probably met an item that was moved to another chain. */ - if (get_nulls_value(node) != hash) + if (get_nulls_value(node) != slot) goto begin; if (result) {