From 6aaf47fa48d3c44280810b1b470261d340e4ed87 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 30 Apr 2007 00:26:00 -0700 Subject: [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 Signed-off-by: David S. Miller --- net/ipv4/udp.c | 171 ++++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 114 insertions(+), 57 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index cec0f2cc49b..144970704c2 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -114,14 +114,33 @@ DEFINE_RWLOCK(udp_hash_lock); static int udp_port_rover; -static inline int __udp_lib_lport_inuse(__u16 num, struct hlist_head udptable[]) +/* + * Note about this hash function : + * Typical use is probably daddr = 0, only dport is going to vary hash + */ +static inline unsigned int hash_port_and_addr(__u16 port, __be32 addr) +{ + addr ^= addr >> 16; + addr ^= addr >> 8; + return port ^ addr; +} + +static inline int __udp_lib_port_inuse(unsigned int hash, int port, + __be32 daddr, struct hlist_head udptable[]) { struct sock *sk; struct hlist_node *node; + struct inet_sock *inet; - sk_for_each(sk, node, &udptable[num & (UDP_HTABLE_SIZE - 1)]) - if (sk->sk_hash == num) + sk_for_each(sk, node, &udptable[hash & (UDP_HTABLE_SIZE - 1)]) { + if (sk->sk_hash != hash) + continue; + inet = inet_sk(sk); + if (inet->num != port) + continue; + if (inet->rcv_saddr == daddr) return 1; + } return 0; } @@ -142,6 +161,7 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum, struct hlist_node *node; struct hlist_head *head; struct sock *sk2; + unsigned int hash; int error = 1; write_lock_bh(&udp_hash_lock); @@ -156,7 +176,9 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum, for (i = 0; i < UDP_HTABLE_SIZE; i++, result++) { int size; - head = &udptable[result & (UDP_HTABLE_SIZE - 1)]; + hash = hash_port_and_addr(result, + inet_sk(sk)->rcv_saddr); + head = &udptable[hash & (UDP_HTABLE_SIZE - 1)]; if (hlist_empty(head)) { if (result > sysctl_local_port_range[1]) result = sysctl_local_port_range[0] + @@ -181,7 +203,10 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum, result = sysctl_local_port_range[0] + ((result - sysctl_local_port_range[0]) & (UDP_HTABLE_SIZE - 1)); - if (! __udp_lib_lport_inuse(result, udptable)) + hash = hash_port_and_addr(result, + inet_sk(sk)->rcv_saddr); + if (! __udp_lib_port_inuse(hash, result, + inet_sk(sk)->rcv_saddr, udptable)) break; } if (i >= (1 << 16) / UDP_HTABLE_SIZE) @@ -189,11 +214,13 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum, gotit: *port_rover = snum = result; } else { - head = &udptable[snum & (UDP_HTABLE_SIZE - 1)]; + hash = hash_port_and_addr(snum, inet_sk(sk)->rcv_saddr); + head = &udptable[hash & (UDP_HTABLE_SIZE - 1)]; sk_for_each(sk2, node, head) - if (sk2->sk_hash == snum && + if (sk2->sk_hash == hash && sk2 != sk && + inet_sk(sk2)->num == snum && (!sk2->sk_reuse || !sk->sk_reuse) && (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if || sk2->sk_bound_dev_if == sk->sk_bound_dev_if) && @@ -201,9 +228,9 @@ gotit: goto fail; } inet_sk(sk)->num = snum; - sk->sk_hash = snum; + sk->sk_hash = hash; if (sk_unhashed(sk)) { - head = &udptable[snum & (UDP_HTABLE_SIZE - 1)]; + head = &udptable[hash & (UDP_HTABLE_SIZE - 1)]; sk_add_node(sk, head); sock_prot_inc_use(sk->sk_prot); } @@ -242,63 +269,78 @@ static struct sock *__udp4_lib_lookup(__be32 saddr, __be16 sport, { struct sock *sk, *result = NULL; struct hlist_node *node; - unsigned short hnum = ntohs(dport); - int badness = -1; + unsigned int hash, hashwild; + int score, best = -1; + + hash = hash_port_and_addr(ntohs(dport), daddr); + hashwild = hash_port_and_addr(ntohs(dport), 0); read_lock(&udp_hash_lock); - sk_for_each(sk, node, &udptable[hnum & (UDP_HTABLE_SIZE - 1)]) { + +lookup: + + sk_for_each(sk, node, &udptable[hash & (UDP_HTABLE_SIZE - 1)]) { struct inet_sock *inet = inet_sk(sk); - if (sk->sk_hash == hnum && !ipv6_only_sock(sk)) { - int score = (sk->sk_family == PF_INET ? 1 : 0); - if (inet->rcv_saddr) { - if (inet->rcv_saddr != daddr) - continue; - score+=2; - } - if (inet->daddr) { - if (inet->daddr != saddr) - continue; - score+=2; - } - if (inet->dport) { - if (inet->dport != sport) - continue; - score+=2; - } - if (sk->sk_bound_dev_if) { - if (sk->sk_bound_dev_if != dif) - continue; - score+=2; - } - if (score == 9) { - result = sk; - break; - } else if (score > badness) { - result = sk; - badness = score; - } + if (sk->sk_hash != hash || ipv6_only_sock(sk) || + inet->num != dport) + continue; + + score = (sk->sk_family == PF_INET ? 1 : 0); + if (inet->rcv_saddr) { + if (inet->rcv_saddr != daddr) + continue; + score+=2; + } + if (inet->daddr) { + if (inet->daddr != saddr) + continue; + score+=2; + } + if (inet->dport) { + if (inet->dport != sport) + continue; + score+=2; + } + if (sk->sk_bound_dev_if) { + if (sk->sk_bound_dev_if != dif) + continue; + score+=2; + } + if (score == 9) { + result = sk; + goto found; + } else if (score > best) { + result = sk; + best = score; } } + + if (hash != hashwild) { + hash = hashwild; + goto lookup; + } +found: if (result) sock_hold(result); read_unlock(&udp_hash_lock); return result; } -static inline struct sock *udp_v4_mcast_next(struct sock *sk, - __be16 loc_port, __be32 loc_addr, - __be16 rmt_port, __be32 rmt_addr, - int dif) +static inline struct sock *udp_v4_mcast_next( + struct sock *sk, + unsigned int hnum, __be16 loc_port, __be32 loc_addr, + __be16 rmt_port, __be32 rmt_addr, + int dif) { struct hlist_node *node; struct sock *s = sk; - unsigned short hnum = ntohs(loc_port); sk_for_each_from(s, node) { struct inet_sock *inet = inet_sk(s); if (s->sk_hash != hnum || + inet->num != loc_port || (inet->daddr && inet->daddr != rmt_addr) || (inet->dport != rmt_port && inet->dport) || (inet->rcv_saddr && inet->rcv_saddr != loc_addr) || @@ -1129,29 +1171,44 @@ static int __udp4_lib_mcast_deliver(struct sk_buff *skb, __be32 saddr, __be32 daddr, struct hlist_head udptable[]) { - struct sock *sk; + struct sock *sk, *skw, *sknext; int dif; + unsigned int hash = hash_port_and_addr(ntohs(uh->dest), daddr); + unsigned int hashwild = hash_port_and_addr(ntohs(uh->dest), 0); - read_lock(&udp_hash_lock); - sk = sk_head(&udptable[ntohs(uh->dest) & (UDP_HTABLE_SIZE - 1)]); dif = skb->dev->ifindex; - sk = udp_v4_mcast_next(sk, uh->dest, daddr, uh->source, saddr, dif); - if (sk) { - struct sock *sknext = NULL; + read_lock(&udp_hash_lock); + + sk = sk_head(&udptable[hash & (UDP_HTABLE_SIZE - 1)]); + skw = sk_head(&udptable[hashwild & (UDP_HTABLE_SIZE - 1)]); + + sk = udp_v4_mcast_next(sk, hash, uh->dest, daddr, uh->source, saddr, dif); + if (!sk) { + hash = hashwild; + sk = udp_v4_mcast_next(skw, hash, uh->dest, daddr, uh->source, + saddr, dif); + } + if (sk) { do { struct sk_buff *skb1 = skb; - - sknext = udp_v4_mcast_next(sk_next(sk), uh->dest, daddr, - uh->source, saddr, dif); + sknext = udp_v4_mcast_next(sk_next(sk), hash, uh->dest, + daddr, uh->source, saddr, dif); + if (!sknext && hash != hashwild) { + hash = hashwild; + sknext = udp_v4_mcast_next(skw, hash, uh->dest, + daddr, uh->source, saddr, dif); + } if (sknext) skb1 = skb_clone(skb, GFP_ATOMIC); if (skb1) { int ret = udp_queue_rcv_skb(sk, skb1); if (ret > 0) - /* we should probably re-process instead - * of dropping packets here. */ + /* + * we should probably re-process + * instead of dropping packets here. + */ kfree_skb(skb1); } sk = sknext; -- cgit v1.2.3-70-g09d2