Following INET/TCP socket lookup changes, modify UDP socket lookup to let
BPF program select a receiving socket before searching for a socket by
destination address and port as usual.
Lookup of connected sockets that match packet 4-tuple is unaffected by this
change. BPF program runs, and potentially overrides the lookup result, only
if a 4-tuple match was not found.
Suggested-by: Marek Majkowski <marek@xxxxxxxxxxxxxx>
Reviewed-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
Signed-off-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
---
net/ipv4/udp.c | 36 ++++++++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d4842f29294a..18d8432f6551 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -460,7 +460,7 @@ 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 *result;
+ struct sock *result, *sk, *reuse_sk;
unsigned short hnum = ntohs(dport);
unsigned int hash2, slot2;
struct udp_hslot *hslot2;
@@ -469,18 +469,38 @@ struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
slot2 = hash2 & udptable->mask;
hslot2 = &udptable->hash2[slot2];
+ /* Lookup connected or non-wildcard socket */
result = udp4_lib_lookup2(net, saddr, sport,
daddr, hnum, dif, sdif,
hslot2, skb);
- if (!result) {
- hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
- slot2 = hash2 & udptable->mask;
- hslot2 = &udptable->hash2[slot2];
+ if (!IS_ERR_OR_NULL(result) && result->sk_state == TCP_ESTABLISHED)
+ goto done;
- result = udp4_lib_lookup2(net, saddr, sport,
- htonl(INADDR_ANY), hnum, dif, sdif,
- hslot2, skb);
+ /* Lookup redirect from BPF */
+ sk = inet_lookup_run_bpf(net, udptable->protocol,
+ saddr, sport, daddr, hnum);
+ if (IS_ERR(sk))
+ return NULL;
+ if (sk) {
+ reuse_sk = lookup_reuseport(net, sk, skb,
+ saddr, sport, daddr, hnum);
+ result = reuse_sk ? : sk;
+ goto done;
}
+
+ /* Got non-wildcard socket or error on first lookup */
+ if (result)
+ goto done;
+
+ /* Lookup wildcard sockets */
+ hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
+ slot2 = hash2 & udptable->mask;
+ hslot2 = &udptable->hash2[slot2];
+
+ result = udp4_lib_lookup2(net, saddr, sport,
+ htonl(INADDR_ANY), hnum, dif, sdif,
+ hslot2, skb);
+done:
if (IS_ERR(result))
return NULL;
return result;
--
2.25.3
