net: export inet_lookup_reuseport and inet6_lookup_reuseport

Rename the existing reuseport helpers for IPv4 and IPv6 so that they
can be invoked in the follow up commit. Export them so that building
DCCP and IPv6 as a module works.

No change in functionality.
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/r/20230720-so-reuseport-v6-3-7021b683cdae@isovalent.comSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

include/net/inet6_hashtables.h

@@ -48,6 +48,13 @@ struct sock *__inet6_lookup_established(struct net *net,
 					const u16 hnum, const int dif,
 					const int sdif);
 
+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);
+
 struct sock *inet6_lookup_listener(struct net *net,
 				   struct inet_hashinfo *hashinfo,
 				   struct sk_buff *skb, int doff,

include/net/inet_hashtables.h

@@ -379,6 +379,11 @@ struct sock *__inet_lookup_established(struct net *net,
 				       const __be32 daddr, const u16 hnum,
 				       const int dif, const int sdif);
 
+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);
+
 static inline struct sock *
 	inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo,
 				const __be32 saddr, const __be16 sport,

net/ipv4/inet_hashtables.c

@@ -332,10 +332,10 @@ static inline int compute_score(struct sock *sk, struct net *net,
 	return score;
 }
 
-static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk,
-					    struct sk_buff *skb, int doff,
-					    __be32 saddr, __be16 sport,
-					    __be32 daddr, unsigned short hnum)
+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)
 {
 	struct sock *reuse_sk = NULL;
 	u32 phash;
@@ -346,6 +346,7 @@ static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk,
 	}
 	return reuse_sk;
 }
+EXPORT_SYMBOL_GPL(inet_lookup_reuseport);
 
 /*
  * Here are some nice properties to exploit here. The BSD API
@@ -369,8 +370,8 @@ static struct sock *inet_lhash2_lookup(struct net *net,
 	sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) {
 		score = compute_score(sk, net, hnum, daddr, dif, sdif);
 		if (score > hiscore) {
-			result = lookup_reuseport(net, sk, skb, doff,
-						  saddr, sport, daddr, hnum);
+			result = inet_lookup_reuseport(net, sk, skb, doff,
+						       saddr, sport, daddr, hnum);
 			if (result)
 				return result;
 
@@ -399,7 +400,7 @@ static inline struct sock *inet_lookup_run_bpf(struct net *net,
 	if (no_reuseport || IS_ERR_OR_NULL(sk))
 		return sk;
 
-	reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
+	reuse_sk = inet_lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
 	if (reuse_sk)
 		sk = reuse_sk;
 	return sk;

net/ipv6/inet6_hashtables.c

@@ -111,12 +111,12 @@ static inline int compute_score(struct sock *sk, struct net *net,
 	return score;
 }
 
-static inline struct sock *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)
+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)
 {
 	struct sock *reuse_sk = NULL;
 	u32 phash;
@@ -127,6 +127,7 @@ static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk,
 	}
 	return reuse_sk;
 }
+EXPORT_SYMBOL_GPL(inet6_lookup_reuseport);
 
 /* called with rcu_read_lock() */
 static struct sock *inet6_lhash2_lookup(struct net *net,
@@ -143,8 +144,8 @@ static struct sock *inet6_lhash2_lookup(struct net *net,
 	sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) {
 		score = compute_score(sk, net, hnum, daddr, dif, sdif);
 		if (score > hiscore) {
-			result = lookup_reuseport(net, sk, skb, doff,
-						  saddr, sport, daddr, hnum);
+			result = inet6_lookup_reuseport(net, sk, skb, doff,
+							saddr, sport, daddr, hnum);
 			if (result)
 				return result;
 
@@ -175,7 +176,7 @@ static inline struct sock *inet6_lookup_run_bpf(struct net *net,
 	if (no_reuseport || IS_ERR_OR_NULL(sk))
 		return sk;
 
-	reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
+	reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum);
 	if (reuse_sk)
 		sk = reuse_sk;
 	return sk;