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authorPeter Oskolkov <posk@google.com>2018-12-12 13:15:33 -0800
committerDavid S. Miller <davem@davemloft.net>2018-12-14 15:55:20 -0800
commit4cdeeee9252af1ba50482f91d615f326365306bd (patch)
tree62cc2eca1cfed387c81af3053e04b50339e316a4 /net/ipv4/udp.c
parent8e2ea53a83dfb4b892ba35ddd9e78e6091202fa6 (diff)
downloadlinux-4cdeeee9252af1ba50482f91d615f326365306bd.tar.bz2
net: udp: prefer listeners bound to an address
A relatively common use case is to have several IPs configured on a host, and have different listeners for each of them. We would like to add a "catch all" listener on addr_any, to match incoming connections not served by any of the listeners bound to a specific address. However, port-only lookups can match addr_any sockets when sockets listening on specific addresses are present if so_reuseport flag is set. This patch eliminates lookups into port-only hashtable, as lookups by (addr,port) tuple are easily available. In addition, compute_score() is tweaked to _not_ match addr_any sockets to specific addresses, as hash collisions could result in the unwanted behavior described above. Tested: the patch compiles; full test in the last patch in this patchset. Existing reuseport_* selftests also pass. Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Peter Oskolkov <posk@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/udp.c')
-rw-r--r--net/ipv4/udp.c76
1 files changed, 19 insertions, 57 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index aff2a8e99e01..3fb0ed5e4789 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -380,15 +380,12 @@ static int compute_score(struct sock *sk, struct net *net,
ipv6_only_sock(sk))
return -1;
- score = (sk->sk_family == PF_INET) ? 2 : 1;
- inet = inet_sk(sk);
+ if (sk->sk_rcv_saddr != daddr)
+ return -1;
- if (inet->inet_rcv_saddr) {
- if (inet->inet_rcv_saddr != daddr)
- return -1;
- score += 4;
- }
+ score = (sk->sk_family == PF_INET) ? 2 : 1;
+ inet = inet_sk(sk);
if (inet->inet_daddr) {
if (inet->inet_daddr != saddr)
return -1;
@@ -464,65 +461,30 @@ struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
__be16 sport, __be32 daddr, __be16 dport, int dif,
int sdif, struct udp_table *udptable, struct sk_buff *skb)
{
- struct sock *sk, *result;
+ struct sock *result;
unsigned short hnum = ntohs(dport);
- unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
- struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
+ unsigned int hash2, slot2;
+ struct udp_hslot *hslot2;
bool exact_dif = udp_lib_exact_dif_match(net, skb);
- int score, badness;
- u32 hash = 0;
- if (hslot->count > 10) {
- hash2 = ipv4_portaddr_hash(net, daddr, hnum);
+ hash2 = ipv4_portaddr_hash(net, daddr, hnum);
+ slot2 = hash2 & udptable->mask;
+ hslot2 = &udptable->hash2[slot2];
+
+ result = udp4_lib_lookup2(net, saddr, sport,
+ daddr, hnum, dif, sdif,
+ exact_dif, hslot2, skb);
+ if (!result) {
+ hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), 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, sdif,
+ htonl(INADDR_ANY), hnum, dif, sdif,
exact_dif, hslot2, skb);
- if (!result) {
- unsigned int old_slot2 = slot2;
- hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
- slot2 = hash2 & udptable->mask;
- /* avoid searching the same slot again. */
- if (unlikely(slot2 == old_slot2))
- return result;
-
- hslot2 = &udptable->hash2[slot2];
- if (hslot->count < hslot2->count)
- goto begin;
-
- result = udp4_lib_lookup2(net, saddr, sport,
- daddr, hnum, dif, sdif,
- exact_dif, hslot2, skb);
- }
- if (unlikely(IS_ERR(result)))
- return NULL;
- return result;
- }
-begin:
- result = NULL;
- badness = 0;
- sk_for_each_rcu(sk, &hslot->head) {
- score = compute_score(sk, net, saddr, sport,
- daddr, hnum, dif, sdif, exact_dif);
- if (score > badness) {
- if (sk->sk_reuseport) {
- hash = udp_ehashfn(net, daddr, hnum,
- saddr, sport);
- result = reuseport_select_sock(sk, hash, skb,
- sizeof(struct udphdr));
- if (unlikely(IS_ERR(result)))
- return NULL;
- if (result)
- return result;
- }
- result = sk;
- badness = score;
- }
}
+ if (unlikely(IS_ERR(result)))
+ return NULL;
return result;
}
EXPORT_SYMBOL_GPL(__udp4_lib_lookup);