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161 lines
3.4 KiB
161 lines
3.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Pluggable TCP upper layer protocol support. |
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* |
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* Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved. |
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* Copyright (c) 2016-2017, Dave Watson <[email protected]>. All rights reserved. |
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* |
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*/ |
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#include <linux/module.h> |
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#include <linux/mm.h> |
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#include <linux/types.h> |
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#include <linux/list.h> |
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#include <linux/gfp.h> |
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#include <net/tcp.h> |
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static DEFINE_SPINLOCK(tcp_ulp_list_lock); |
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static LIST_HEAD(tcp_ulp_list); |
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/* Simple linear search, don't expect many entries! */ |
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static struct tcp_ulp_ops *tcp_ulp_find(const char *name) |
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{ |
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struct tcp_ulp_ops *e; |
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list_for_each_entry_rcu(e, &tcp_ulp_list, list, |
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lockdep_is_held(&tcp_ulp_list_lock)) { |
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if (strcmp(e->name, name) == 0) |
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return e; |
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} |
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return NULL; |
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} |
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static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name) |
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{ |
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const struct tcp_ulp_ops *ulp = NULL; |
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rcu_read_lock(); |
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ulp = tcp_ulp_find(name); |
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#ifdef CONFIG_MODULES |
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if (!ulp && capable(CAP_NET_ADMIN)) { |
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rcu_read_unlock(); |
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request_module("tcp-ulp-%s", name); |
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rcu_read_lock(); |
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ulp = tcp_ulp_find(name); |
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} |
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#endif |
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if (!ulp || !try_module_get(ulp->owner)) |
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ulp = NULL; |
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rcu_read_unlock(); |
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return ulp; |
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} |
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/* Attach new upper layer protocol to the list |
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* of available protocols. |
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*/ |
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int tcp_register_ulp(struct tcp_ulp_ops *ulp) |
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{ |
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int ret = 0; |
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spin_lock(&tcp_ulp_list_lock); |
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if (tcp_ulp_find(ulp->name)) |
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ret = -EEXIST; |
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else |
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list_add_tail_rcu(&ulp->list, &tcp_ulp_list); |
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spin_unlock(&tcp_ulp_list_lock); |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(tcp_register_ulp); |
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void tcp_unregister_ulp(struct tcp_ulp_ops *ulp) |
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{ |
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spin_lock(&tcp_ulp_list_lock); |
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list_del_rcu(&ulp->list); |
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spin_unlock(&tcp_ulp_list_lock); |
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synchronize_rcu(); |
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} |
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EXPORT_SYMBOL_GPL(tcp_unregister_ulp); |
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/* Build string with list of available upper layer protocl values */ |
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void tcp_get_available_ulp(char *buf, size_t maxlen) |
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{ |
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struct tcp_ulp_ops *ulp_ops; |
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size_t offs = 0; |
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*buf = '\0'; |
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rcu_read_lock(); |
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list_for_each_entry_rcu(ulp_ops, &tcp_ulp_list, list) { |
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offs += snprintf(buf + offs, maxlen - offs, |
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"%s%s", |
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offs == 0 ? "" : " ", ulp_ops->name); |
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if (WARN_ON_ONCE(offs >= maxlen)) |
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break; |
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} |
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rcu_read_unlock(); |
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} |
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void tcp_update_ulp(struct sock *sk, struct proto *proto, |
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void (*write_space)(struct sock *sk)) |
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{ |
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struct inet_connection_sock *icsk = inet_csk(sk); |
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if (icsk->icsk_ulp_ops->update) |
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icsk->icsk_ulp_ops->update(sk, proto, write_space); |
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} |
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void tcp_cleanup_ulp(struct sock *sk) |
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{ |
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struct inet_connection_sock *icsk = inet_csk(sk); |
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/* No sock_owned_by_me() check here as at the time the |
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* stack calls this function, the socket is dead and |
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* about to be destroyed. |
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*/ |
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if (!icsk->icsk_ulp_ops) |
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return; |
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if (icsk->icsk_ulp_ops->release) |
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icsk->icsk_ulp_ops->release(sk); |
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module_put(icsk->icsk_ulp_ops->owner); |
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icsk->icsk_ulp_ops = NULL; |
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} |
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static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops) |
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{ |
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struct inet_connection_sock *icsk = inet_csk(sk); |
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int err; |
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err = -EEXIST; |
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if (icsk->icsk_ulp_ops) |
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goto out_err; |
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err = ulp_ops->init(sk); |
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if (err) |
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goto out_err; |
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icsk->icsk_ulp_ops = ulp_ops; |
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return 0; |
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out_err: |
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module_put(ulp_ops->owner); |
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return err; |
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} |
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int tcp_set_ulp(struct sock *sk, const char *name) |
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{ |
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const struct tcp_ulp_ops *ulp_ops; |
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sock_owned_by_me(sk); |
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ulp_ops = __tcp_ulp_find_autoload(name); |
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if (!ulp_ops) |
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return -ENOENT; |
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return __tcp_set_ulp(sk, ulp_ops); |
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}
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