On 10/23/2018 06:58 PM, Jeff Barnhill wrote:
> icmp6_send() function is expensive on systems with a large number of
> interfaces. Every time it’s called, it has to verify that the source
> address does not correspond to an existing anycast address by looping
> through every device and every anycast address on the device. This can
> result in significant delays for a CPU when there are a large number of
> neighbors and ND timers are frequently timing out and calling
> neigh_invalidate().
>
> Add anycast addresses to a global hashtable to allow quick searching for
> matching anycast addresses. This is based on inet6_addr_lst in addrconf.c.
>
> Signed-off-by: Jeff Barnhill <0xeff...@gmail.com>
> ---
> include/net/addrconf.h | 2 +
> include/net/if_inet6.h | 8 +++
> net/ipv6/af_inet6.c | 5 ++
> net/ipv6/anycast.c | 132
> ++++++++++++++++++++++++++++++++++++++++++++++++-
> 4 files changed, 145 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/addrconf.h b/include/net/addrconf.h
> index 6def0351bcc3..0cee3f99c41d 100644
> --- a/include/net/addrconf.h
> +++ b/include/net/addrconf.h
> @@ -312,6 +312,8 @@ bool ipv6_chk_acast_addr(struct net *net, struct
> net_device *dev,
> const struct in6_addr *addr);
> bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev,
> const struct in6_addr *addr);
> +int anycast_init(void);
> +void anycast_cleanup(void);
>
> /* Device notifier */
> int register_inet6addr_notifier(struct notifier_block *nb);
> diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
> index d7578cf49c3a..55a4a1d8cebc 100644
> --- a/include/net/if_inet6.h
> +++ b/include/net/if_inet6.h
> @@ -142,6 +142,14 @@ struct ipv6_ac_socklist {
> struct ipv6_ac_socklist *acl_next;
> };
>
> +struct ipv6_ac_addrlist {
> + struct in6_addr acal_addr;
> + possible_net_t acal_pnet;
> + int acal_users;
That would be a refcount_t acal_users; so that CONFIG_REFCOUNT_FULL brings
debugging for free.
> + struct hlist_node acal_lst; /* inet6_acaddr_lst */
> + struct rcu_head rcu;
> +};
> +
> struct ifacaddr6 {
> struct in6_addr aca_addr;
> struct fib6_info *aca_rt;
> diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
> index 9a4261e50272..971a05fdd3bd 100644
> --- a/net/ipv6/af_inet6.c
> +++ b/net/ipv6/af_inet6.c
> @@ -1001,6 +1001,9 @@ static int __init inet6_init(void)
> err = ip6_flowlabel_init();
> if (err)
> goto ip6_flowlabel_fail;
> + err = anycast_init();
> + if (err)
> + goto anycast_fail;
> err = addrconf_init();
> if (err)
> goto addrconf_fail;
> @@ -1091,6 +1094,8 @@ static int __init inet6_init(void)
> ipv6_exthdrs_fail:
> addrconf_cleanup();
> addrconf_fail:
> + anycast_cleanup();
> +anycast_fail:
> ip6_flowlabel_cleanup();
> ip6_flowlabel_fail:
> ndisc_late_cleanup();
> diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
> index 4e0ff7031edd..def1e156d857 100644
> --- a/net/ipv6/anycast.c
> +++ b/net/ipv6/anycast.c
> @@ -44,8 +44,22 @@
>
> #include <net/checksum.h>
>
> +#define IN6_ADDR_HSIZE_SHIFT 8
> +#define IN6_ADDR_HSIZE BIT(IN6_ADDR_HSIZE_SHIFT)
> +/* anycast address hash table
> + */
> +static struct hlist_head inet6_acaddr_lst[IN6_ADDR_HSIZE];
> +static DEFINE_SPINLOCK(acaddr_hash_lock);
> +
> static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr
> *addr);
>
> +static u32 inet6_acaddr_hash(struct net *net, const struct in6_addr *addr)
> +{
> + u32 val = ipv6_addr_hash(addr) ^ net_hash_mix(net);
> +
> + return hash_32(val, IN6_ADDR_HSIZE_SHIFT);
> +}
> +
> /*
> * socket join an anycast group
> */
> @@ -204,6 +218,83 @@ void ipv6_sock_ac_close(struct sock *sk)
> rtnl_unlock();
> }
>
> +static struct ipv6_ac_addrlist *acal_alloc(struct net *net,
> + const struct in6_addr *addr)
> +{
> + struct ipv6_ac_addrlist *acal;
> +
> + acal = kzalloc(sizeof(*acal), GFP_ATOMIC);
> + if (!acal)
> + return NULL;
> +
> + acal->acal_addr = *addr;
> + write_pnet(&acal->acal_pnet, get_net(net));
I am not sure why you grab a reference on the netns.
The ipv6 address will be freed at some point before the netns disappears.
It would automatically remove the associated struct ipv6_ac_addrlist.
> + acal->acal_users = 1;
> + INIT_HLIST_NODE(&acal->acal_lst);
> +
> + return acal;
> +}
> +
> +static void acal_free_rcu(struct rcu_head *h)
> +{
> + struct ipv6_ac_addrlist *acal;
> +
> + acal = container_of(h, struct ipv6_ac_addrlist, rcu);
> + WARN_ON(acal->acal_users);
Not needed with refcount_t debugging infra.
> + put_net(read_pnet(&acal->acal_pnet));
> + kfree(acal);
So this could use kfree_rcu() in the caller, and get rid of acal_free_rcu()
completely.
> +}
> +
> +static int ipv6_add_acaddr_hash(struct net *net, const struct in6_addr *addr)
> +{
> + unsigned int hash = inet6_acaddr_hash(net, addr);
> + struct ipv6_ac_addrlist *acal;
> + int err = 0;
> +
> + spin_lock(&acaddr_hash_lock);
> + hlist_for_each_entry(acal, &inet6_acaddr_lst[hash], acal_lst) {
> + if (!net_eq(read_pnet(&acal->acal_pnet), net))
> + continue;
> + if (ipv6_addr_equal(&acal->acal_addr, addr)) {
> + acal->acal_users++;
> + goto out;
> + }
> + }
> +
> + acal = acal_alloc(net, addr);
> + if (!acal) {
> + err = -ENOMEM;
> + goto out;
> + }
> +
> + hlist_add_head_rcu(&acal->acal_lst, &inet6_acaddr_lst[hash]);
> +
> +out:
> + spin_unlock(&acaddr_hash_lock);
> + return err;
> +}
> +
> +static void ipv6_del_acaddr_hash(struct net *net, const struct in6_addr
> *addr)
> +{
> + unsigned int hash = inet6_acaddr_hash(net, addr);
> + struct ipv6_ac_addrlist *acal;
> +
> + spin_lock(&acaddr_hash_lock);
> + hlist_for_each_entry(acal, &inet6_acaddr_lst[hash], acal_lst) {
> + if (!net_eq(read_pnet(&acal->acal_pnet), net))
> + continue;
> + if (ipv6_addr_equal(&acal->acal_addr, addr)) {
> + if (--acal->acal_users < 1) {
> + hlist_del_init_rcu(&acal->acal_lst);
> + call_rcu(&acal->rcu, acal_free_rcu);
> + }
> + spin_unlock(&acaddr_hash_lock);
> + return;
> + }
> + }
> + spin_unlock(&acaddr_hash_lock);
> +}
> +
> static void aca_get(struct ifacaddr6 *aca)
> {
> refcount_inc(&aca->aca_refcnt);
> @@ -275,6 +366,13 @@ int __ipv6_dev_ac_inc(struct inet6_dev *idev, const
> struct in6_addr *addr)
> err = -ENOMEM;
> goto out;
> }
> + err = ipv6_add_acaddr_hash(dev_net(idev->dev), addr);
> + if (err) {
> + fib6_info_release(f6i);
> + fib6_info_release(f6i);
Double call to fib6_info_release() ? Why ?
> + kfree(aca);
> + goto out;
> + }
>
> aca->aca_next = idev->ac_list;
> idev->ac_list = aca;
> @@ -324,6 +422,7 @@ int __ipv6_dev_ac_dec(struct inet6_dev *idev, const
> struct in6_addr *addr)
> prev_aca->aca_next = aca->aca_next;
> else
> idev->ac_list = aca->aca_next;
> + ipv6_del_acaddr_hash(dev_net(idev->dev), &aca->aca_addr);
> write_unlock_bh(&idev->lock);
> addrconf_leave_solict(idev, &aca->aca_addr);
>
> @@ -350,6 +449,8 @@ void ipv6_ac_destroy_dev(struct inet6_dev *idev)
> write_lock_bh(&idev->lock);
> while ((aca = idev->ac_list) != NULL) {
> idev->ac_list = aca->aca_next;
> + ipv6_del_acaddr_hash(dev_net(idev->dev), &aca->aca_addr);
> +
> write_unlock_bh(&idev->lock);
>
> addrconf_leave_solict(idev, &aca->aca_addr);
> @@ -391,16 +492,22 @@ bool ipv6_chk_acast_addr(struct net *net, struct
> net_device *dev,
> const struct in6_addr *addr)
> {
> bool found = false;
> + unsigned int hash = inet6_acaddr_hash(net, addr);
> + struct ipv6_ac_addrlist *acal;
Reorder variable declaration in longest to shortest (reverse xmas tree),
per David Miller request :)
>
> rcu_read_lock();
> if (dev)
> found = ipv6_chk_acast_dev(dev, addr);
> else
> - for_each_netdev_rcu(net, dev)
> - if (ipv6_chk_acast_dev(dev, addr)) {
> + hlist_for_each_entry_rcu(acal, &inet6_acaddr_lst[hash],
> + acal_lst) {
> + if (!net_eq(read_pnet(&acal->acal_pnet), net))
> + continue;
> + if (ipv6_addr_equal(&acal->acal_addr, addr)) {
> found = true;
> break;
> }
> + }
> rcu_read_unlock();
> return found;
> }
> @@ -539,4 +646,25 @@ void ac6_proc_exit(struct net *net)
> {
> remove_proc_entry("anycast6", net->proc_net);
> }
> +
> +/* Init / cleanup code
> + */
> +int __init anycast_init(void)
> +{
> + int i;
> +
> + for (i = 0; i < IN6_ADDR_HSIZE; i++)
> + INIT_HLIST_HEAD(&inet6_acaddr_lst[i]);
> + return 0;
> +}
> +
> +void anycast_cleanup(void)
> +{
> + int i;
> +
> + spin_lock(&acaddr_hash_lock);
> + for (i = 0; i < IN6_ADDR_HSIZE; i++)
> + WARN_ON(!hlist_empty(&inet6_acaddr_lst[i]));
> + spin_unlock(&acaddr_hash_lock);
> +}
> #endif
>
