diff options
Diffstat (limited to 'net/ipv4/tcp_ulp.c')
| -rw-r--r-- | net/ipv4/tcp_ulp.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c new file mode 100644 index 000000000..2aa442128 --- /dev/null +++ b/net/ipv4/tcp_ulp.c @@ -0,0 +1,168 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Pluggable TCP upper layer protocol support. + * + * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved. + * Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved. + * + */ + +#include <linux/module.h> +#include <linux/mm.h> +#include <linux/types.h> +#include <linux/list.h> +#include <linux/gfp.h> +#include <net/tcp.h> + +static DEFINE_SPINLOCK(tcp_ulp_list_lock); +static LIST_HEAD(tcp_ulp_list); + +/* Simple linear search, don't expect many entries! */ +static struct tcp_ulp_ops *tcp_ulp_find(const char *name) +{ + struct tcp_ulp_ops *e; + + list_for_each_entry_rcu(e, &tcp_ulp_list, list, + lockdep_is_held(&tcp_ulp_list_lock)) { + if (strcmp(e->name, name) == 0) + return e; + } + + return NULL; +} + +static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name) +{ + const struct tcp_ulp_ops *ulp = NULL; + + rcu_read_lock(); + ulp = tcp_ulp_find(name); + +#ifdef CONFIG_MODULES + if (!ulp && capable(CAP_NET_ADMIN)) { + rcu_read_unlock(); + request_module("tcp-ulp-%s", name); + rcu_read_lock(); + ulp = tcp_ulp_find(name); + } +#endif + if (!ulp || !try_module_get(ulp->owner)) + ulp = NULL; + + rcu_read_unlock(); + return ulp; +} + +/* Attach new upper layer protocol to the list + * of available protocols. + */ +int tcp_register_ulp(struct tcp_ulp_ops *ulp) +{ + int ret = 0; + + spin_lock(&tcp_ulp_list_lock); + if (tcp_ulp_find(ulp->name)) + ret = -EEXIST; + else + list_add_tail_rcu(&ulp->list, &tcp_ulp_list); + spin_unlock(&tcp_ulp_list_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(tcp_register_ulp); + +void tcp_unregister_ulp(struct tcp_ulp_ops *ulp) +{ + spin_lock(&tcp_ulp_list_lock); + list_del_rcu(&ulp->list); + spin_unlock(&tcp_ulp_list_lock); + + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(tcp_unregister_ulp); + +/* Build string with list of available upper layer protocl values */ +void tcp_get_available_ulp(char *buf, size_t maxlen) +{ + struct tcp_ulp_ops *ulp_ops; + size_t offs = 0; + + *buf = '\0'; + rcu_read_lock(); + list_for_each_entry_rcu(ulp_ops, &tcp_ulp_list, list) { + offs += snprintf(buf + offs, maxlen - offs, + "%s%s", + offs == 0 ? "" : " ", ulp_ops->name); + + if (WARN_ON_ONCE(offs >= maxlen)) + break; + } + rcu_read_unlock(); +} + +void tcp_update_ulp(struct sock *sk, struct proto *proto, + void (*write_space)(struct sock *sk)) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + if (icsk->icsk_ulp_ops->update) + icsk->icsk_ulp_ops->update(sk, proto, write_space); +} + +void tcp_cleanup_ulp(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + /* No sock_owned_by_me() check here as at the time the + * stack calls this function, the socket is dead and + * about to be destroyed. + */ + if (!icsk->icsk_ulp_ops) + return; + + if (icsk->icsk_ulp_ops->release) + icsk->icsk_ulp_ops->release(sk); + module_put(icsk->icsk_ulp_ops->owner); + + icsk->icsk_ulp_ops = NULL; +} + +static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + int err; + + err = -EEXIST; + if (icsk->icsk_ulp_ops) + goto out_err; + + if (sk->sk_socket) + clear_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags); + + err = -ENOTCONN; + if (!ulp_ops->clone && sk->sk_state == TCP_LISTEN) + goto out_err; + + err = ulp_ops->init(sk); + if (err) + goto out_err; + + icsk->icsk_ulp_ops = ulp_ops; + return 0; +out_err: + module_put(ulp_ops->owner); + return err; +} + +int tcp_set_ulp(struct sock *sk, const char *name) +{ + const struct tcp_ulp_ops *ulp_ops; + + sock_owned_by_me(sk); + + ulp_ops = __tcp_ulp_find_autoload(name); + if (!ulp_ops) + return -ENOENT; + + return __tcp_set_ulp(sk, ulp_ops); +} |