From e94a62f507f9498e5f4b2c69ef181b3402934c2a Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 30 Nov 2017 15:39:34 +0100 Subject: [PATCH] net/reuseport: drop legacy code Since commit e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection") and commit c125e80b8868 ("soreuseport: fast reuseport TCP socket selection") the relevant reuseport socket matching the current packet is selected by the reuseport_select_sock() call. The only exceptions are invalid BPF filters/filters returning out-of-range indices. In the latter case the code implicitly falls back to using the hash demultiplexing, but instead of selecting the socket inside the reuseport_select_sock() function, it relies on the hash selection logic introduced with the early soreuseport implementation. With this patch, in case of a BPF filter returning a bad socket index value, we fall back to hash-based selection inside the reuseport_select_sock() body, so that we can drop some duplicate code in the ipv4 and ipv6 stack. This also allows faster lookup in the above scenario and will allow us to avoid computing the hash value for successful, BPF based demultiplexing - in a later patch. Signed-off-by: Paolo Abeni Acked-by: Craig Gallek Signed-off-by: David S. Miller --- net/core/sock_reuseport.c | 4 +++- net/ipv4/inet_hashtables.c | 11 ++--------- net/ipv4/udp.c | 22 ++++------------------ net/ipv6/inet6_hashtables.c | 11 ++--------- net/ipv6/udp.c | 22 ++++------------------ 5 files changed, 15 insertions(+), 55 deletions(-) diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c index 5eeb1d20cc38..c5bb52bc73a1 100644 --- a/net/core/sock_reuseport.c +++ b/net/core/sock_reuseport.c @@ -235,7 +235,9 @@ struct sock *reuseport_select_sock(struct sock *sk, if (prog && skb) sk2 = run_bpf(reuse, socks, prog, skb, hdr_len); - else + + /* no bpf or invalid bpf result: fall back to hash usage */ + if (!sk2) sk2 = reuse->socks[reciprocal_scale(hash, socks)]; } diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index e7d15fb0d94d..427b705d7c64 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -216,32 +216,25 @@ struct sock *__inet_lookup_listener(struct net *net, { unsigned int hash = inet_lhashfn(net, hnum); struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; - int score, hiscore = 0, matches = 0, reuseport = 0; bool exact_dif = inet_exact_dif_match(net, skb); struct sock *sk, *result = NULL; + int score, hiscore = 0; u32 phash = 0; sk_for_each_rcu(sk, &ilb->head) { score = compute_score(sk, net, hnum, daddr, dif, sdif, exact_dif); if (score > hiscore) { - reuseport = sk->sk_reuseport; - if (reuseport) { + if (sk->sk_reuseport) { phash = inet_ehashfn(net, daddr, hnum, saddr, sport); result = reuseport_select_sock(sk, phash, skb, doff); if (result) return result; - matches = 1; } result = sk; hiscore = score; - } else if (score == hiscore && reuseport) { - matches++; - if (reciprocal_scale(phash, matches) == 0) - result = sk; - phash = next_pseudo_random32(phash); } } return result; diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index e4ff25c947c5..36f857c87fe2 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -445,7 +445,7 @@ static struct sock *udp4_lib_lookup2(struct net *net, struct sk_buff *skb) { struct sock *sk, *result; - int score, badness, matches = 0, reuseport = 0; + int score, badness; u32 hash = 0; result = NULL; @@ -454,23 +454,16 @@ static struct sock *udp4_lib_lookup2(struct net *net, score = compute_score(sk, net, saddr, sport, daddr, hnum, dif, sdif, exact_dif); if (score > badness) { - reuseport = sk->sk_reuseport; - if (reuseport) { + if (sk->sk_reuseport) { hash = udp_ehashfn(net, daddr, hnum, saddr, sport); result = reuseport_select_sock(sk, hash, skb, sizeof(struct udphdr)); if (result) return result; - matches = 1; } badness = score; result = sk; - } else if (score == badness && reuseport) { - matches++; - if (reciprocal_scale(hash, matches) == 0) - result = sk; - hash = next_pseudo_random32(hash); } } return result; @@ -488,7 +481,7 @@ struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask); struct udp_hslot *hslot2, *hslot = &udptable->hash[slot]; bool exact_dif = udp_lib_exact_dif_match(net, skb); - int score, badness, matches = 0, reuseport = 0; + int score, badness; u32 hash = 0; if (hslot->count > 10) { @@ -526,23 +519,16 @@ begin: score = compute_score(sk, net, saddr, sport, daddr, hnum, dif, sdif, exact_dif); if (score > badness) { - reuseport = sk->sk_reuseport; - if (reuseport) { + if (sk->sk_reuseport) { hash = udp_ehashfn(net, daddr, hnum, saddr, sport); result = reuseport_select_sock(sk, hash, skb, sizeof(struct udphdr)); if (result) return result; - matches = 1; } result = sk; badness = score; - } else if (score == badness && reuseport) { - matches++; - if (reciprocal_scale(hash, matches) == 0) - result = sk; - hash = next_pseudo_random32(hash); } } return result; diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index b01858f5deb1..0d1451381f5c 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -134,31 +134,24 @@ struct sock *inet6_lookup_listener(struct net *net, { unsigned int hash = inet_lhashfn(net, hnum); struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; - int score, hiscore = 0, matches = 0, reuseport = 0; bool exact_dif = inet6_exact_dif_match(net, skb); struct sock *sk, *result = NULL; + int score, hiscore = 0; u32 phash = 0; sk_for_each(sk, &ilb->head) { score = compute_score(sk, net, hnum, daddr, dif, sdif, exact_dif); if (score > hiscore) { - reuseport = sk->sk_reuseport; - if (reuseport) { + if (sk->sk_reuseport) { phash = inet6_ehashfn(net, daddr, hnum, saddr, sport); result = reuseport_select_sock(sk, phash, skb, doff); if (result) return result; - matches = 1; } result = sk; hiscore = score; - } else if (score == hiscore && reuseport) { - matches++; - if (reciprocal_scale(phash, matches) == 0) - result = sk; - phash = next_pseudo_random32(phash); } } return result; diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 3f30fa313bf2..c9f91c28b81d 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -184,7 +184,7 @@ static struct sock *udp6_lib_lookup2(struct net *net, struct udp_hslot *hslot2, struct sk_buff *skb) { struct sock *sk, *result; - int score, badness, matches = 0, reuseport = 0; + int score, badness; u32 hash = 0; result = NULL; @@ -193,8 +193,7 @@ static struct sock *udp6_lib_lookup2(struct net *net, score = compute_score(sk, net, saddr, sport, daddr, hnum, dif, sdif, exact_dif); if (score > badness) { - reuseport = sk->sk_reuseport; - if (reuseport) { + if (sk->sk_reuseport) { hash = udp6_ehashfn(net, daddr, hnum, saddr, sport); @@ -202,15 +201,9 @@ static struct sock *udp6_lib_lookup2(struct net *net, sizeof(struct udphdr)); if (result) return result; - matches = 1; } result = sk; badness = score; - } else if (score == badness && reuseport) { - matches++; - if (reciprocal_scale(hash, matches) == 0) - result = sk; - hash = next_pseudo_random32(hash); } } return result; @@ -228,7 +221,7 @@ struct sock *__udp6_lib_lookup(struct net *net, unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask); struct udp_hslot *hslot2, *hslot = &udptable->hash[slot]; bool exact_dif = udp6_lib_exact_dif_match(net, skb); - int score, badness, matches = 0, reuseport = 0; + int score, badness; u32 hash = 0; if (hslot->count > 10) { @@ -267,23 +260,16 @@ begin: score = compute_score(sk, net, saddr, sport, daddr, hnum, dif, sdif, exact_dif); if (score > badness) { - reuseport = sk->sk_reuseport; - if (reuseport) { + if (sk->sk_reuseport) { hash = udp6_ehashfn(net, daddr, hnum, saddr, sport); result = reuseport_select_sock(sk, hash, skb, sizeof(struct udphdr)); if (result) return result; - matches = 1; } result = sk; badness = score; - } else if (score == badness && reuseport) { - matches++; - if (reciprocal_scale(hash, matches) == 0) - result = sk; - hash = next_pseudo_random32(hash); } } return result; -- 2.30.2