[PATCH] INET : IPV4 UDP lookups converted to a 2 pass algo
Some people want to have many UDP sockets, binded to a single port but many different addresses. We currently hash all those sockets into a single chain. Processing of incoming packets is very expensive, because the whole chain must be examined to find the best match. I chose in this patch to hash UDP sockets with a hash function that take into account both their port number and address : This has a drawback because we need two lookups : one with a given address, one with a wildcard (null) address. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
David S. Miller
parent
65def812ab
commit
6aaf47fa48
171
net/ipv4/udp.c
171
net/ipv4/udp.c
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@ -114,14 +114,33 @@ DEFINE_RWLOCK(udp_hash_lock);
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static int udp_port_rover;
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static inline int __udp_lib_lport_inuse(__u16 num, struct hlist_head udptable[])
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/*
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* Note about this hash function :
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* Typical use is probably daddr = 0, only dport is going to vary hash
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*/
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static inline unsigned int hash_port_and_addr(__u16 port, __be32 addr)
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{
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addr ^= addr >> 16;
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addr ^= addr >> 8;
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return port ^ addr;
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}
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static inline int __udp_lib_port_inuse(unsigned int hash, int port,
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__be32 daddr, struct hlist_head udptable[])
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{
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struct sock *sk;
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struct hlist_node *node;
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struct inet_sock *inet;
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sk_for_each(sk, node, &udptable[num & (UDP_HTABLE_SIZE - 1)])
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if (sk->sk_hash == num)
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sk_for_each(sk, node, &udptable[hash & (UDP_HTABLE_SIZE - 1)]) {
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if (sk->sk_hash != hash)
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continue;
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inet = inet_sk(sk);
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if (inet->num != port)
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continue;
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if (inet->rcv_saddr == daddr)
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return 1;
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}
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return 0;
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}
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@ -142,6 +161,7 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum,
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struct hlist_node *node;
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struct hlist_head *head;
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struct sock *sk2;
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unsigned int hash;
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int error = 1;
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write_lock_bh(&udp_hash_lock);
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@ -156,7 +176,9 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum,
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for (i = 0; i < UDP_HTABLE_SIZE; i++, result++) {
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int size;
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head = &udptable[result & (UDP_HTABLE_SIZE - 1)];
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hash = hash_port_and_addr(result,
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inet_sk(sk)->rcv_saddr);
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head = &udptable[hash & (UDP_HTABLE_SIZE - 1)];
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if (hlist_empty(head)) {
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if (result > sysctl_local_port_range[1])
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result = sysctl_local_port_range[0] +
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@ -181,7 +203,10 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum,
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result = sysctl_local_port_range[0]
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+ ((result - sysctl_local_port_range[0]) &
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(UDP_HTABLE_SIZE - 1));
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if (! __udp_lib_lport_inuse(result, udptable))
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hash = hash_port_and_addr(result,
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inet_sk(sk)->rcv_saddr);
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if (! __udp_lib_port_inuse(hash, result,
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inet_sk(sk)->rcv_saddr, udptable))
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break;
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}
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if (i >= (1 << 16) / UDP_HTABLE_SIZE)
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@ -189,11 +214,13 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum,
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gotit:
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*port_rover = snum = result;
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} else {
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head = &udptable[snum & (UDP_HTABLE_SIZE - 1)];
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hash = hash_port_and_addr(snum, inet_sk(sk)->rcv_saddr);
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head = &udptable[hash & (UDP_HTABLE_SIZE - 1)];
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sk_for_each(sk2, node, head)
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if (sk2->sk_hash == snum &&
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if (sk2->sk_hash == hash &&
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sk2 != sk &&
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inet_sk(sk2)->num == snum &&
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(!sk2->sk_reuse || !sk->sk_reuse) &&
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(!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
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|| sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
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@ -201,9 +228,9 @@ gotit:
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goto fail;
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}
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inet_sk(sk)->num = snum;
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sk->sk_hash = snum;
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sk->sk_hash = hash;
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if (sk_unhashed(sk)) {
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head = &udptable[snum & (UDP_HTABLE_SIZE - 1)];
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head = &udptable[hash & (UDP_HTABLE_SIZE - 1)];
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sk_add_node(sk, head);
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sock_prot_inc_use(sk->sk_prot);
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}
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@ -242,63 +269,78 @@ static struct sock *__udp4_lib_lookup(__be32 saddr, __be16 sport,
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{
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struct sock *sk, *result = NULL;
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struct hlist_node *node;
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unsigned short hnum = ntohs(dport);
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int badness = -1;
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unsigned int hash, hashwild;
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int score, best = -1;
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hash = hash_port_and_addr(ntohs(dport), daddr);
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hashwild = hash_port_and_addr(ntohs(dport), 0);
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read_lock(&udp_hash_lock);
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sk_for_each(sk, node, &udptable[hnum & (UDP_HTABLE_SIZE - 1)]) {
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lookup:
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sk_for_each(sk, node, &udptable[hash & (UDP_HTABLE_SIZE - 1)]) {
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struct inet_sock *inet = inet_sk(sk);
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if (sk->sk_hash == hnum && !ipv6_only_sock(sk)) {
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int score = (sk->sk_family == PF_INET ? 1 : 0);
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if (inet->rcv_saddr) {
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if (inet->rcv_saddr != daddr)
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continue;
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score+=2;
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}
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if (inet->daddr) {
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if (inet->daddr != saddr)
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continue;
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score+=2;
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}
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if (inet->dport) {
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if (inet->dport != sport)
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continue;
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score+=2;
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}
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if (sk->sk_bound_dev_if) {
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if (sk->sk_bound_dev_if != dif)
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continue;
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score+=2;
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}
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if (score == 9) {
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result = sk;
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break;
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} else if (score > badness) {
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result = sk;
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badness = score;
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}
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if (sk->sk_hash != hash || ipv6_only_sock(sk) ||
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inet->num != dport)
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continue;
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score = (sk->sk_family == PF_INET ? 1 : 0);
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if (inet->rcv_saddr) {
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if (inet->rcv_saddr != daddr)
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continue;
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score+=2;
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}
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if (inet->daddr) {
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if (inet->daddr != saddr)
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continue;
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score+=2;
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}
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if (inet->dport) {
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if (inet->dport != sport)
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continue;
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score+=2;
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}
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if (sk->sk_bound_dev_if) {
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if (sk->sk_bound_dev_if != dif)
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continue;
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score+=2;
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}
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if (score == 9) {
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result = sk;
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goto found;
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} else if (score > best) {
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result = sk;
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best = score;
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}
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}
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if (hash != hashwild) {
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hash = hashwild;
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goto lookup;
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}
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found:
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if (result)
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sock_hold(result);
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read_unlock(&udp_hash_lock);
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return result;
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}
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static inline struct sock *udp_v4_mcast_next(struct sock *sk,
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__be16 loc_port, __be32 loc_addr,
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__be16 rmt_port, __be32 rmt_addr,
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int dif)
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static inline struct sock *udp_v4_mcast_next(
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struct sock *sk,
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unsigned int hnum, __be16 loc_port, __be32 loc_addr,
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__be16 rmt_port, __be32 rmt_addr,
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int dif)
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{
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struct hlist_node *node;
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struct sock *s = sk;
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unsigned short hnum = ntohs(loc_port);
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sk_for_each_from(s, node) {
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struct inet_sock *inet = inet_sk(s);
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if (s->sk_hash != hnum ||
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inet->num != loc_port ||
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(inet->daddr && inet->daddr != rmt_addr) ||
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(inet->dport != rmt_port && inet->dport) ||
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(inet->rcv_saddr && inet->rcv_saddr != loc_addr) ||
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@ -1129,29 +1171,44 @@ static int __udp4_lib_mcast_deliver(struct sk_buff *skb,
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__be32 saddr, __be32 daddr,
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struct hlist_head udptable[])
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{
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struct sock *sk;
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struct sock *sk, *skw, *sknext;
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int dif;
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unsigned int hash = hash_port_and_addr(ntohs(uh->dest), daddr);
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unsigned int hashwild = hash_port_and_addr(ntohs(uh->dest), 0);
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dif = skb->dev->ifindex;
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read_lock(&udp_hash_lock);
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sk = sk_head(&udptable[ntohs(uh->dest) & (UDP_HTABLE_SIZE - 1)]);
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dif = skb->dev->ifindex;
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sk = udp_v4_mcast_next(sk, uh->dest, daddr, uh->source, saddr, dif);
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if (sk) {
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struct sock *sknext = NULL;
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sk = sk_head(&udptable[hash & (UDP_HTABLE_SIZE - 1)]);
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skw = sk_head(&udptable[hashwild & (UDP_HTABLE_SIZE - 1)]);
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sk = udp_v4_mcast_next(sk, hash, uh->dest, daddr, uh->source, saddr, dif);
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if (!sk) {
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hash = hashwild;
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sk = udp_v4_mcast_next(skw, hash, uh->dest, daddr, uh->source,
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saddr, dif);
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}
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if (sk) {
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do {
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struct sk_buff *skb1 = skb;
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sknext = udp_v4_mcast_next(sk_next(sk), uh->dest, daddr,
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uh->source, saddr, dif);
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sknext = udp_v4_mcast_next(sk_next(sk), hash, uh->dest,
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daddr, uh->source, saddr, dif);
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if (!sknext && hash != hashwild) {
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hash = hashwild;
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sknext = udp_v4_mcast_next(skw, hash, uh->dest,
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daddr, uh->source, saddr, dif);
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}
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if (sknext)
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skb1 = skb_clone(skb, GFP_ATOMIC);
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if (skb1) {
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int ret = udp_queue_rcv_skb(sk, skb1);
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if (ret > 0)
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/* we should probably re-process instead
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* of dropping packets here. */
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/*
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* we should probably re-process
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* instead of dropping packets here.
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*/
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kfree_skb(skb1);
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}
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sk = sknext;
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