net: remove duplicate reuseport_lookup functions

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.

There are two differences between the reuseport_lookup helpers:

1. They call different hash functions depending on protocol
2. UDP reuseport_lookup checks that sk_state != TCP_ESTABLISHED

Move the check for sk_state into the caller and use the INDIRECT_CALL
infrastructure to cut down the helpers to one per IP version.
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/r/20230720-so-reuseport-v6-4-7021b683cdae@isovalent.comSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

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);
+
+inet6_ehashfn_t inet6_ehashfn;
+
+INDIRECT_CALLABLE_DECLARE(inet6_ehashfn_t udp6_ehashfn);
+
 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,

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);
+
+inet_ehashfn_t inet_ehashfn;
+
+INDIRECT_CALLABLE_DECLARE(inet_ehashfn_t udp_ehashfn);
+
 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 */

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;
 
@@ -39,6 +39,7 @@ static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
 	return __inet_ehashfn(laddr, lport, faddr, fport,
 			      inet_ehash_secret + net_hash_mix(net));
 }
+EXPORT_SYMBOL_GPL(inet_ehashfn);
 
 /* This function handles inet_sock, but also timewait and request sockets
  * for IPv4/IPv6.
@@ -332,16 +333,20 @@ static inline int compute_score(struct sock *sk, struct net *net,
 	return score;
 }
 
+INDIRECT_CALLABLE_DECLARE(inet_ehashfn_t udp_ehashfn);
+
 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, udp_ehashfn, inet_ehashfn,
+					net, daddr, hnum, saddr, sport);
 		reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
 	}
 	return reuse_sk;
@@ -371,7 +376,7 @@ 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;
 
@@ -400,7 +405,8 @@ 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;

net/ipv4/udp.c

@@ -406,9 +406,9 @@ 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;
 
@@ -418,22 +418,6 @@ 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,
@@ -452,7 +436,14 @@ static struct sock *udp4_lib_lookup2(struct net *net,
 				      daddr, hnum, dif, sdif);
 		if (score > badness) {
 			badness = score;
-			result = lookup_reuseport(net, sk, skb, saddr, sport, daddr, hnum);
+
+			if (sk->sk_state == TCP_ESTABLISHED) {
+				result = sk;
+				continue;
+			}
+
+			result = inet_lookup_reuseport(net, sk, skb, sizeof(struct udphdr),
+						       saddr, sport, daddr, hnum, udp_ehashfn);
 			if (!result) {
 				result = sk;
 				continue;
@@ -491,7 +482,8 @@ 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;

net/ipv6/inet6_hashtables.c

@@ -39,6 +39,7 @@ u32 inet6_ehashfn(const struct net *net,
 	return __inet6_ehashfn(lhash, lport, fhash, fport,
 			       inet6_ehash_secret + net_hash_mix(net));
 }
+EXPORT_SYMBOL_GPL(inet6_ehashfn);
 
 /*
  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
@@ -111,18 +112,22 @@ static inline int compute_score(struct sock *sk, struct net *net,
 	return score;
 }
 
+INDIRECT_CALLABLE_DECLARE(inet6_ehashfn_t udp6_ehashfn);
+
 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 *reuse_sk = NULL;
 	u32 phash;
 
 	if (sk->sk_reuseport) {
-		phash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
+		phash = INDIRECT_CALL_INET(ehashfn, udp6_ehashfn, inet6_ehashfn,
+					   net, daddr, hnum, saddr, sport);
 		reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
 	}
 	return reuse_sk;
@@ -145,7 +150,7 @@ 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;
 
@@ -176,7 +181,8 @@ 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;

net/ipv6/udp.c

@@ -71,11 +71,12 @@ 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;
@@ -160,24 +161,6 @@ 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,
@@ -195,7 +178,14 @@ static struct sock *udp6_lib_lookup2(struct net *net,
 				      daddr, hnum, dif, sdif);
 		if (score > badness) {
 			badness = score;
-			result = lookup_reuseport(net, sk, skb, saddr, sport, daddr, hnum);
+
+			if (sk->sk_state == TCP_ESTABLISHED) {
+				result = sk;
+				continue;
+			}
+
+			result = inet6_lookup_reuseport(net, sk, skb, sizeof(struct udphdr),
+							saddr, sport, daddr, hnum, udp6_ehashfn);
 			if (!result) {
 				result = sk;
 				continue;
@@ -235,7 +225,8 @@ 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;