diff options
| -rw-r--r-- | include/net/sock.h | 2 | ||||
| -rw-r--r-- | include/net/sock_reuseport.h | 20 | ||||
| -rw-r--r-- | net/core/Makefile | 2 | ||||
| -rw-r--r-- | net/core/sock_reuseport.c | 173 |
4 files changed, 196 insertions, 1 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 3794cdde837a..e830c1006935 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -318,6 +318,7 @@ struct cg_proto; * @sk_error_report: callback to indicate errors (e.g. %MSG_ERRQUEUE) * @sk_backlog_rcv: callback to process the backlog * @sk_destruct: called at sock freeing time, i.e. when all refcnt == 0 + * @sk_reuseport_cb: reuseport group container */ struct sock { /* @@ -453,6 +454,7 @@ struct sock { int (*sk_backlog_rcv)(struct sock *sk, struct sk_buff *skb); void (*sk_destruct)(struct sock *sk); + struct sock_reuseport __rcu *sk_reuseport_cb; }; #define __sk_user_data(sk) ((*((void __rcu **)&(sk)->sk_user_data))) diff --git a/include/net/sock_reuseport.h b/include/net/sock_reuseport.h new file mode 100644 index 000000000000..67d1eb8fd7af --- /dev/null +++ b/include/net/sock_reuseport.h @@ -0,0 +1,20 @@ +#ifndef _SOCK_REUSEPORT_H +#define _SOCK_REUSEPORT_H + +#include <linux/types.h> +#include <net/sock.h> + +struct sock_reuseport { + struct rcu_head rcu; + + u16 max_socks; /* length of socks */ + u16 num_socks; /* elements in socks */ + struct sock *socks[0]; /* array of sock pointers */ +}; + +extern int reuseport_alloc(struct sock *sk); +extern int reuseport_add_sock(struct sock *sk, const struct sock *sk2); +extern void reuseport_detach_sock(struct sock *sk); +extern struct sock *reuseport_select_sock(struct sock *sk, u32 hash); + +#endif /* _SOCK_REUSEPORT_H */ diff --git a/net/core/Makefile b/net/core/Makefile index 086b01fbe1bd..0b835de04de3 100644 --- a/net/core/Makefile +++ b/net/core/Makefile @@ -9,7 +9,7 @@ obj-$(CONFIG_SYSCTL) += sysctl_net_core.o obj-y += dev.o ethtool.o dev_addr_lists.o dst.o netevent.o \ neighbour.o rtnetlink.o utils.o link_watch.o filter.o \ - sock_diag.o dev_ioctl.o tso.o + sock_diag.o dev_ioctl.o tso.o sock_reuseport.o obj-$(CONFIG_XFRM) += flow.o obj-y += net-sysfs.o diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c new file mode 100644 index 000000000000..963c8d5f3027 --- /dev/null +++ b/net/core/sock_reuseport.c @@ -0,0 +1,173 @@ +/* + * To speed up listener socket lookup, create an array to store all sockets + * listening on the same port. This allows a decision to be made after finding + * the first socket. + */ + +#include <net/sock_reuseport.h> +#include <linux/rcupdate.h> + +#define INIT_SOCKS 128 + +static DEFINE_SPINLOCK(reuseport_lock); + +static struct sock_reuseport *__reuseport_alloc(u16 max_socks) +{ + size_t size = sizeof(struct sock_reuseport) + + sizeof(struct sock *) * max_socks; + struct sock_reuseport *reuse = kzalloc(size, GFP_ATOMIC); + + if (!reuse) + return NULL; + + reuse->max_socks = max_socks; + + return reuse; +} + +int reuseport_alloc(struct sock *sk) +{ + struct sock_reuseport *reuse; + + /* bh lock used since this function call may precede hlist lock in + * soft irq of receive path or setsockopt from process context + */ + spin_lock_bh(&reuseport_lock); + WARN_ONCE(rcu_dereference_protected(sk->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)), + "multiple allocations for the same socket"); + reuse = __reuseport_alloc(INIT_SOCKS); + if (!reuse) { + spin_unlock_bh(&reuseport_lock); + return -ENOMEM; + } + + reuse->socks[0] = sk; + reuse->num_socks = 1; + rcu_assign_pointer(sk->sk_reuseport_cb, reuse); + + spin_unlock_bh(&reuseport_lock); + + return 0; +} +EXPORT_SYMBOL(reuseport_alloc); + +static struct sock_reuseport *reuseport_grow(struct sock_reuseport *reuse) +{ + struct sock_reuseport *more_reuse; + u32 more_socks_size, i; + + more_socks_size = reuse->max_socks * 2U; + if (more_socks_size > U16_MAX) + return NULL; + + more_reuse = __reuseport_alloc(more_socks_size); + if (!more_reuse) + return NULL; + + more_reuse->max_socks = more_socks_size; + more_reuse->num_socks = reuse->num_socks; + + memcpy(more_reuse->socks, reuse->socks, + reuse->num_socks * sizeof(struct sock *)); + + for (i = 0; i < reuse->num_socks; ++i) + rcu_assign_pointer(reuse->socks[i]->sk_reuseport_cb, + more_reuse); + + kfree_rcu(reuse, rcu); + return more_reuse; +} + +/** + * reuseport_add_sock - Add a socket to the reuseport group of another. + * @sk: New socket to add to the group. + * @sk2: Socket belonging to the existing reuseport group. + * May return ENOMEM and not add socket to group under memory pressure. + */ +int reuseport_add_sock(struct sock *sk, const struct sock *sk2) +{ + struct sock_reuseport *reuse; + + spin_lock_bh(&reuseport_lock); + reuse = rcu_dereference_protected(sk2->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)), + WARN_ONCE(rcu_dereference_protected(sk->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)), + "socket already in reuseport group"); + + if (reuse->num_socks == reuse->max_socks) { + reuse = reuseport_grow(reuse); + if (!reuse) { + spin_unlock_bh(&reuseport_lock); + return -ENOMEM; + } + } + + reuse->socks[reuse->num_socks] = sk; + /* paired with smp_rmb() in reuseport_select_sock() */ + smp_wmb(); + reuse->num_socks++; + rcu_assign_pointer(sk->sk_reuseport_cb, reuse); + + spin_unlock_bh(&reuseport_lock); + + return 0; +} +EXPORT_SYMBOL(reuseport_add_sock); + +void reuseport_detach_sock(struct sock *sk) +{ + struct sock_reuseport *reuse; + int i; + + spin_lock_bh(&reuseport_lock); + reuse = rcu_dereference_protected(sk->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)); + rcu_assign_pointer(sk->sk_reuseport_cb, NULL); + + for (i = 0; i < reuse->num_socks; i++) { + if (reuse->socks[i] == sk) { + reuse->socks[i] = reuse->socks[reuse->num_socks - 1]; + reuse->num_socks--; + if (reuse->num_socks == 0) + kfree_rcu(reuse, rcu); + break; + } + } + spin_unlock_bh(&reuseport_lock); +} +EXPORT_SYMBOL(reuseport_detach_sock); + +/** + * reuseport_select_sock - Select a socket from an SO_REUSEPORT group. + * @sk: First socket in the group. + * @hash: Use this hash to select. + * Returns a socket that should receive the packet (or NULL on error). + */ +struct sock *reuseport_select_sock(struct sock *sk, u32 hash) +{ + struct sock_reuseport *reuse; + struct sock *sk2 = NULL; + u16 socks; + + rcu_read_lock(); + reuse = rcu_dereference(sk->sk_reuseport_cb); + + /* if memory allocation failed or add call is not yet complete */ + if (!reuse) + goto out; + + socks = READ_ONCE(reuse->num_socks); + if (likely(socks)) { + /* paired with smp_wmb() in reuseport_add_sock() */ + smp_rmb(); + + sk2 = reuse->socks[reciprocal_scale(hash, socks)]; + } + +out: + rcu_read_unlock(); + return sk2; +} +EXPORT_SYMBOL(reuseport_select_sock); |