Add a new hash list, hash4, in udp table. It will be used to implement
4-tuple hash for connected udp sockets. This patch adds the hlist to
table, and implements helpers and the initialization. 4-tuple hash is
implemented in the following patch.

Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
Signed-off-by: Cambda Zhu <cambda@linux.alibaba.com>
Signed-off-by: Fred Chen <fred.cc@alibaba-inc.com>
Signed-off-by: Yubing Qiu <yubing.qiuyubing@alibaba-inc.com>
---
 include/linux/udp.h |  7 +++++++
 include/net/udp.h   | 16 +++++++++++++++-
 net/ipv4/udp.c      | 17 +++++++++++++----
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/include/linux/udp.h b/include/linux/udp.h
index 3eb3f2b9a2a0..c04808360a05 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -56,6 +56,10 @@ struct udp_sock {
 	int		 pending;	/* Any pending frames ? */
 	__u8		 encap_type;	/* Is this an Encapsulation socket? */
 
+	/* For UDP 4-tuple hash */
+	__u16 udp_lrpa_hash;
+	struct hlist_node udp_lrpa_node;
+
 	/*
 	 * Following member retains the information to create a UDP header
 	 * when the socket is uncorked.
@@ -206,6 +210,9 @@ static inline void udp_allow_gso(struct sock *sk)
 #define udp_portaddr_for_each_entry_rcu(__sk, list) \
 	hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node)
 
+#define udp_lrpa_for_each_entry_rcu(__up, list) \
+	hlist_for_each_entry_rcu(__up, list, udp_lrpa_node)
+
 #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
 
 #endif	/* _LINUX_UDP_H */
diff --git a/include/net/udp.h b/include/net/udp.h
index 595364729138..80f9622d0db3 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -50,7 +50,7 @@ struct udp_skb_cb {
 #define UDP_SKB_CB(__skb)	((struct udp_skb_cb *)((__skb)->cb))
 
 /**
- *	struct udp_hslot - UDP hash slot used by udp_table.hash
+ *	struct udp_hslot - UDP hash slot used by udp_table.hash/hash4
  *
  *	@head:	head of list of sockets
  *	@count:	number of sockets in 'head' list
@@ -79,12 +79,15 @@ struct udp_hslot_main {
  *
  *	@hash:	hash table, sockets are hashed on (local port)
  *	@hash2:	hash table, sockets are hashed on (local port, local address)
+ *	@hash4:	hash table, connected sockets are hashed on
+ *		(local port, local address, remote port, remote address)
  *	@mask:	number of slots in hash tables, minus 1
  *	@log:	log2(number of slots in hash table)
  */
 struct udp_table {
 	struct udp_hslot	*hash;
 	struct udp_hslot_main	*hash2;
+	struct udp_hslot	*hash4;
 	unsigned int		mask;
 	unsigned int		log;
 };
@@ -113,6 +116,17 @@ static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
 	return &table->hash2[hash & table->mask].hslot;
 }
 
+static inline struct udp_hslot *udp_hashslot4(struct udp_table *table,
+					      unsigned int hash)
+{
+	return &table->hash4[hash & table->mask];
+}
+
+static inline bool udp_hashed4(const struct sock *sk)
+{
+	return !hlist_unhashed(&udp_sk(sk)->udp_lrpa_node);
+}
+
 extern struct proto udp_prot;
 
 extern atomic_long_t udp_memory_allocated;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 36d617235acd..9f4cc6f778ce 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -3425,7 +3425,7 @@ void __init udp_table_init(struct udp_table *table, const char *name)
 {
 	unsigned int i, slot_size;
 
-	slot_size = sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main);
+	slot_size = 2 * sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main);
 	table->hash = alloc_large_system_hash(name,
 					      slot_size,
 					      uhash_entries,
@@ -3437,6 +3437,7 @@ void __init udp_table_init(struct udp_table *table, const char *name)
 					      UDP_HTABLE_SIZE_MAX);
 
 	table->hash2 = (void *)(table->hash + (table->mask + 1));
+	table->hash4 = (void *)(table->hash2 + (table->mask + 1));
 	for (i = 0; i <= table->mask; i++) {
 		INIT_HLIST_HEAD(&table->hash[i].head);
 		table->hash[i].count = 0;
@@ -3448,6 +3449,11 @@ void __init udp_table_init(struct udp_table *table, const char *name)
 		spin_lock_init(&table->hash2[i].hslot.lock);
 		table->hash2[i].hash4_cnt = 0;
 	}
+	for (i = 0; i <= table->mask; i++) {
+		INIT_HLIST_HEAD(&table->hash4[i].head);
+		table->hash4[i].count = 0;
+		spin_lock_init(&table->hash4[i].lock);
+	}
 }
 
 u32 udp_flow_hashrnd(void)
@@ -3480,16 +3486,15 @@ static struct udp_table __net_init *udp_pernet_table_alloc(unsigned int hash_ent
 	if (!udptable)
 		goto out;
 
-	slot_size = sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main);
+	slot_size = 2 * sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main);
 	udptable->hash = vmalloc_huge(hash_entries * slot_size,
 				      GFP_KERNEL_ACCOUNT);
 	if (!udptable->hash)
 		goto free_table;
 
 	udptable->hash2 = UDP_HSLOT_MAIN(udptable->hash + hash_entries);
-	udptable->mask = hash_entries - 1;
+	udptable->hash4 = (struct udp_hslot *)(udptable->hash2 + hash_entries);
 	udptable->log = ilog2(hash_entries);
-
 	for (i = 0; i < hash_entries; i++) {
 		INIT_HLIST_HEAD(&udptable->hash[i].head);
 		udptable->hash[i].count = 0;
@@ -3499,6 +3504,10 @@ static struct udp_table __net_init *udp_pernet_table_alloc(unsigned int hash_ent
 		udptable->hash2[i].hslot.count = 0;
 		spin_lock_init(&udptable->hash2[i].hslot.lock);
 		udptable->hash2[i].hash4_cnt = 0;
+
+		INIT_HLIST_HEAD(&udptable->hash4[i].head);
+		udptable->hash4[i].count = 0;
+		spin_lock_init(&udptable->hash4[i].lock);
 	}
 
 	return udptable;
-- 
2.32.0.3.g01195cf9f

Philo Lu wrote:
> Add a new hash list, hash4, in udp table. It will be used to implement
> 4-tuple hash for connected udp sockets. This patch adds the hlist to
> table, and implements helpers and the initialization. 4-tuple hash is
> implemented in the following patch.
> 
> Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
> Signed-off-by: Cambda Zhu <cambda@linux.alibaba.com>
> Signed-off-by: Fred Chen <fred.cc@alibaba-inc.com>
> Signed-off-by: Yubing Qiu <yubing.qiuyubing@alibaba-inc.com>

> @@ -3480,16 +3486,15 @@ static struct udp_table __net_init *udp_pernet_table_alloc(unsigned int hash_ent
>  	if (!udptable)
>  		goto out;
>  
> -	slot_size = sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main);
> +	slot_size = 2 * sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main);
>  	udptable->hash = vmalloc_huge(hash_entries * slot_size,
>  				      GFP_KERNEL_ACCOUNT);
>  	if (!udptable->hash)
>  		goto free_table;
>  
>  	udptable->hash2 = UDP_HSLOT_MAIN(udptable->hash + hash_entries);
> -	udptable->mask = hash_entries - 1;
> +	udptable->hash4 = (struct udp_hslot *)(udptable->hash2 + hash_entries);

Unintentional removal of the mask assignment?

>  	udptable->log = ilog2(hash_entries);
> -

Unnecessary whitespace line removal

>  	for (i = 0; i < hash_entries; i++) {
>  		INIT_HLIST_HEAD(&udptable->hash[i].head);
>  		udptable->hash[i].count = 0;

On 2024/10/10 21:48, Willem de Bruijn wrote:
> Philo Lu wrote:
>> Add a new hash list, hash4, in udp table. It will be used to implement
>> 4-tuple hash for connected udp sockets. This patch adds the hlist to
>> table, and implements helpers and the initialization. 4-tuple hash is
>> implemented in the following patch.
>>
>> Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
>> Signed-off-by: Cambda Zhu <cambda@linux.alibaba.com>
>> Signed-off-by: Fred Chen <fred.cc@alibaba-inc.com>
>> Signed-off-by: Yubing Qiu <yubing.qiuyubing@alibaba-inc.com>
> 
>> @@ -3480,16 +3486,15 @@ static struct udp_table __net_init *udp_pernet_table_alloc(unsigned int hash_ent
>>   	if (!udptable)
>>   		goto out;
>>   
>> -	slot_size = sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main);
>> +	slot_size = 2 * sizeof(struct udp_hslot) + sizeof(struct udp_hslot_main);
>>   	udptable->hash = vmalloc_huge(hash_entries * slot_size,
>>   				      GFP_KERNEL_ACCOUNT);
>>   	if (!udptable->hash)
>>   		goto free_table;
>>   
>>   	udptable->hash2 = UDP_HSLOT_MAIN(udptable->hash + hash_entries);
>> -	udptable->mask = hash_entries - 1;
>> +	udptable->hash4 = (struct udp_hslot *)(udptable->hash2 + hash_entries);
> 
> Unintentional removal of the mask assignment?
> 

Will fix. Sorry for the mistake.

>>   	udptable->log = ilog2(hash_entries);
>> -
> 
> Unnecessary whitespace line removal
> 

Ditto.

Thank you for review, Willem.
-- 
Philo