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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 | // 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); } |