[PATCH bpf-next v2 3/6] net: remove duplicate reuseport_lookup functions

Lorenz Bauer
2023-06-13T10:15:20Z

There are currently four copies of reuseport_lookup: one each for
(TCP, UDP)x(IPv4, IPv6). This forces us to duplicate all callers of
those functions as well. This is already the case for sk_lookup
helpers (inet,inet6,udp4,udp6)_lookup_run_bpf.

The only difference between the reuseport_lookup helpers is calling
a different hash function. Cut down the number of reuseport_lookup
functions to one per IP version by using the INDIRECT_CALL
infrastructure.

Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
---
include/net/inet6_hashtables.h | 11 ++++++++++-
include/net/inet_hashtables.h | 15 +++++++++-----
net/ipv4/inet_hashtables.c | 22 ++++++++++++++-------
net/ipv4/udp.c | 37 +++++++++++-----------------------
net/ipv6/inet6_hashtables.c | 16 +++++++++++----
net/ipv6/udp.c | 45 +++++++++++++++---------------------------
6 files changed, 75 insertions(+), 71 deletions(-)

diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index 032ddab48f8f..49d586454287 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h
@@ -48,12 +48,21 @@ struct sock *__inet6_lookup_established(struct net *net,
const u16 hnum, const int dif,
const int sdif);

+typedef u32 (*inet6_ehashfn_t)(const struct net *net,
+ const struct in6_addr *laddr, const u16 lport,
+ const struct in6_addr *faddr, const __be16 fport);
+
+u32 inet6_ehashfn(const struct net *net,
+ const struct in6_addr *laddr, const u16 lport,
+ const struct in6_addr *faddr, const __be16 fport);
+
struct sock *inet6_lookup_reuseport(struct net *net, struct sock *sk,
struct sk_buff *skb, int doff,
const struct in6_addr *saddr,
__be16 sport,
const struct in6_addr *daddr,
- unsigned short hnum);
+ unsigned short hnum,
+ inet6_ehashfn_t ehashfn);

struct sock *inet6_lookup_listener(struct net *net,
struct inet_hashinfo *hashinfo,
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 8734f3488f5d..51ab6a1a3601 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -379,10 +379,19 @@ struct sock *__inet_lookup_established(struct net *net,
const __be32 daddr, const u16 hnum,
const int dif, const int sdif);

+typedef u32 (*inet_ehashfn_t)(const struct net *net,
+ const __be32 laddr, const __u16 lport,
+ const __be32 faddr, const __be16 fport);
+
+u32 inet_ehashfn(const struct net *net,
+ const __be32 laddr, const __u16 lport,
+ const __be32 faddr, const __be16 fport);
+
struct sock *inet_lookup_reuseport(struct net *net, struct sock *sk,
struct sk_buff *skb, int doff,
__be32 saddr, __be16 sport,
- __be32 daddr, unsigned short hnum);
+ __be32 daddr, unsigned short hnum,
+ inet_ehashfn_t ehashfn);

static inline struct sock *
inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo,
@@ -453,10 +462,6 @@ static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
refcounted);
}

-u32 inet6_ehashfn(const struct net *net,
- const struct in6_addr *laddr, const u16 lport,
- const struct in6_addr *faddr, const __be16 fport);
-
static inline void sk_daddr_set(struct sock *sk, __be32 addr)
{
sk->sk_daddr = addr; /* alias of inet_daddr */
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 91f9210d4e83..1ec895fd9905 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -28,9 +28,9 @@
#include <net/tcp.h>
#include <net/sock_reuseport.h>

-static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
- const __u16 lport, const __be32 faddr,
- const __be16 fport)
+u32 inet_ehashfn(const struct net *net, const __be32 laddr,
+ const __u16 lport, const __be32 faddr,
+ const __be16 fport)
{
static u32 inet_ehash_secret __read_mostly;

@@ -332,6 +332,10 @@ static inline int compute_score(struct sock *sk, struct net *net,
return score;
}

+INDIRECT_CALLABLE_DECLARE(u32 udp_ehashfn(const struct net *,
+ const __be32, const __u16,
+ const __be32, const __be16));
+
/**
* inet_lookup_reuseport() - execute reuseport logic on AF_INET socket if necessary.
* @net: network namespace.
@@ -342,6 +346,7 @@ static inline int compute_score(struct sock *sk, struct net *net,
* @sport: source port.
* @daddr: destination address.
* @hnum: destination port in host byte order.
+ * @ehashfn: hash function used to generate the fallback hash.
*
* Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to
* the selected sock or an error.
@@ -349,13 +354,15 @@ static inline int compute_score(struct sock *sk, struct net *net,
struct sock *inet_lookup_reuseport(struct net *net, struct sock *sk,
struct sk_buff *skb, int doff,
__be32 saddr, __be16 sport,
- __be32 daddr, unsigned short hnum)
+ __be32 daddr, unsigned short hnum,
+ inet_ehashfn_t ehashfn)
{
struct sock *reuse_sk = NULL;
u32 phash;

if (sk->sk_reuseport) {
- phash = inet_ehashfn(net, daddr, hnum, saddr, sport);
+ phash = INDIRECT_CALL_2(ehashfn, inet_ehashfn, udp_ehashfn,
+ net, daddr, hnum, saddr, sport);
reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
}
return reuse_sk;
@@ -385,7 +392,7 @@ static struct sock *inet_lhash2_lookup(struct net *net,
score = compute_score(sk, net, hnum, daddr, dif, sdif);
if (score > hiscore) {
result = inet_lookup_reuseport(net, sk, skb, doff,
- saddr, sport, daddr, hnum);
+ saddr, sport, daddr, hnum, inet_ehashfn);
if (result)
return result;

@@ -414,7 +421,8 @@ static inline struct sock *inet_lookup_run_bpf(struct net *net,
if (no_reuseport || IS_ERR_OR_NULL(sk))
return sk;

- reuse_sk = inet_lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
+ reuse_sk = inet_lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum,
+ inet_ehashfn);
if (reuse_sk)
sk = reuse_sk;
return sk;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index fd3dae081f3a..10468fe144d0 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -405,9 +405,9 @@ static int compute_score(struct sock *sk, struct net *net,
return score;
}

-static u32 udp_ehashfn(const struct net *net, const __be32 laddr,
- const __u16 lport, const __be32 faddr,
- const __be16 fport)
+INDIRECT_CALLABLE_SCOPE
+u32 udp_ehashfn(const struct net *net, const __be32 laddr, const __u16 lport,
+ const __be32 faddr, const __be16 fport)
{
static u32 udp_ehash_secret __read_mostly;

@@ -417,22 +417,6 @@ static u32 udp_ehashfn(const struct net *net, const __be32 laddr,
udp_ehash_secret + net_hash_mix(net));
}

-static struct sock *lookup_reuseport(struct net *net, struct sock *sk,
- struct sk_buff *skb,
- __be32 saddr, __be16 sport,
- __be32 daddr, unsigned short hnum)
-{
- struct sock *reuse_sk = NULL;
- u32 hash;
-
- if (sk->sk_reuseport && sk->sk_state != TCP_ESTABLISHED) {
- hash = udp_ehashfn(net, daddr, hnum, saddr, sport);
- reuse_sk = reuseport_select_sock(sk, hash, skb,
- sizeof(struct udphdr));
- }
- return reuse_sk;
-}
-
/* called with rcu_read_lock() */
static struct sock *udp4_lib_lookup2(struct net *net,
__be32 saddr, __be16 sport,
@@ -450,11 +434,13 @@ static struct sock *udp4_lib_lookup2(struct net *net,
score = compute_score(sk, net, saddr, sport,
daddr, hnum, dif, sdif);
if (score > badness) {
- result = lookup_reuseport(net, sk, skb,
- saddr, sport, daddr, hnum);
- /* Fall back to scoring if group has connections */
- if (result && !reuseport_has_conns(sk))
- return result;
+ if (sk->sk_state != TCP_ESTABLISHED) {
+ result = inet_lookup_reuseport(net, sk, skb, sizeof(struct udphdr),
+ saddr, sport, daddr, hnum, udp_ehashfn);
+ /* Fall back to scoring if group has connections */
+ if (result && !reuseport_has_conns(sk))
+ return result;
+ }

result = result ? : sk;
badness = score;
@@ -480,7 +466,8 @@ static struct sock *udp4_lookup_run_bpf(struct net *net,
if (no_reuseport || IS_ERR_OR_NULL(sk))
return sk;

- reuse_sk = lookup_reuseport(net, sk, skb, saddr, sport, daddr, hnum);
+ reuse_sk = inet_lookup_reuseport(net, sk, skb, sizeof(struct udphdr),
+ saddr, sport, daddr, hnum, udp_ehashfn);
if (reuse_sk)
sk = reuse_sk;
return sk;
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index 208998694ae3..a350ee40141c 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -111,6 +111,10 @@ static inline int compute_score(struct sock *sk, struct net *net,
return score;
}

+INDIRECT_CALLABLE_DECLARE(u32 udp6_ehashfn(const struct net *,
+ const struct in6_addr *, const u16,
+ const struct in6_addr *, const __be16));
+
/**
* inet6_lookup_reuseport() - execute reuseport logic on AF_INET6 socket if necessary.
* @net: network namespace.
@@ -121,6 +125,7 @@ static inline int compute_score(struct sock *sk, struct net *net,
* @sport: source port.
* @daddr: destination address.
* @hnum: destination port in host byte order.
+ * @ehashfn: hash function used to generate the fallback hash.
*
* Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to
* the selected sock or an error.
@@ -130,13 +135,15 @@ struct sock *inet6_lookup_reuseport(struct net *net, struct sock *sk,
const struct in6_addr *saddr,
__be16 sport,
const struct in6_addr *daddr,
- unsigned short hnum)
+ unsigned short hnum,
+ inet6_ehashfn_t ehashfn)
{
struct sock *reuse_sk = NULL;
u32 phash;

if (sk->sk_reuseport) {
- phash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
+ phash = INDIRECT_CALL_2(ehashfn, inet6_ehashfn, udp6_ehashfn,
+ net, daddr, hnum, saddr, sport);
reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
}
return reuse_sk;
@@ -159,7 +166,7 @@ static struct sock *inet6_lhash2_lookup(struct net *net,
score = compute_score(sk, net, hnum, daddr, dif, sdif);
if (score > hiscore) {
result = inet6_lookup_reuseport(net, sk, skb, doff,
- saddr, sport, daddr, hnum);
+ saddr, sport, daddr, hnum, inet6_ehashfn);
if (result)
return result;

@@ -190,7 +197,8 @@ static inline struct sock *inet6_lookup_run_bpf(struct net *net,
if (no_reuseport || IS_ERR_OR_NULL(sk))
return sk;

- reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
+ reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff,
+ saddr, sport, daddr, hnum, inet6_ehashfn);
if (reuse_sk)
sk = reuse_sk;
return sk;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index e5a337e6b970..2af3a595f38a 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -70,11 +70,12 @@ int udpv6_init_sock(struct sock *sk)
return 0;
}

-static u32 udp6_ehashfn(const struct net *net,
- const struct in6_addr *laddr,
- const u16 lport,
- const struct in6_addr *faddr,
- const __be16 fport)
+INDIRECT_CALLABLE_SCOPE
+u32 udp6_ehashfn(const struct net *net,
+ const struct in6_addr *laddr,
+ const u16 lport,
+ const struct in6_addr *faddr,
+ const __be16 fport)
{
static u32 udp6_ehash_secret __read_mostly;
static u32 udp_ipv6_hash_secret __read_mostly;
@@ -159,24 +160,6 @@ static int compute_score(struct sock *sk, struct net *net,
return score;
}

-static struct sock *lookup_reuseport(struct net *net, struct sock *sk,
- struct sk_buff *skb,
- const struct in6_addr *saddr,
- __be16 sport,
- const struct in6_addr *daddr,
- unsigned int hnum)
-{
- struct sock *reuse_sk = NULL;
- u32 hash;
-
- if (sk->sk_reuseport && sk->sk_state != TCP_ESTABLISHED) {
- hash = udp6_ehashfn(net, daddr, hnum, saddr, sport);
- reuse_sk = reuseport_select_sock(sk, hash, skb,
- sizeof(struct udphdr));
- }
- return reuse_sk;
-}
-
/* called with rcu_read_lock() */
static struct sock *udp6_lib_lookup2(struct net *net,
const struct in6_addr *saddr, __be16 sport,
@@ -193,11 +176,14 @@ static struct sock *udp6_lib_lookup2(struct net *net,
score = compute_score(sk, net, saddr, sport,
daddr, hnum, dif, sdif);
if (score > badness) {
- result = lookup_reuseport(net, sk, skb,
- saddr, sport, daddr, hnum);
- /* Fall back to scoring if group has connections */
- if (result && !reuseport_has_conns(sk))
- return result;
+ if (sk->sk_state != TCP_ESTABLISHED) {
+ result = inet6_lookup_reuseport(net, sk, skb, sizeof(struct udphdr),
+ saddr, sport, daddr, hnum,
+ udp6_ehashfn);
+ /* Fall back to scoring if group has connections */
+ if (result && !reuseport_has_conns(sk))
+ return result;
+ }

result = result ? : sk;
badness = score;
@@ -225,7 +211,8 @@ static inline struct sock *udp6_lookup_run_bpf(struct net *net,
if (no_reuseport || IS_ERR_OR_NULL(sk))
return sk;

- reuse_sk = lookup_reuseport(net, sk, skb, saddr, sport, daddr, hnum);
+ reuse_sk = inet6_lookup_reuseport(net, sk, skb, sizeof(struct udphdr),
+ saddr, sport, daddr, hnum, udp6_ehashfn);
if (reuse_sk)
sk = reuse_sk;
return sk;

--
2.40.1