diff options
| -rw-r--r-- | include/net/rtnetlink.h | 2 | ||||
| -rw-r--r-- | net/core/rtnetlink.c | 113 |
2 files changed, 80 insertions, 35 deletions
diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index ead018744ff5..e326b3f9eb5f 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -17,6 +17,8 @@ int __rtnl_register(int protocol, int msgtype, rtnl_doit_func, rtnl_dumpit_func, unsigned int flags); void rtnl_register(int protocol, int msgtype, rtnl_doit_func, rtnl_dumpit_func, unsigned int flags); +int rtnl_register_module(struct module *owner, int protocol, int msgtype, + rtnl_doit_func, rtnl_dumpit_func, unsigned int flags); int rtnl_unregister(int protocol, int msgtype); void rtnl_unregister_all(int protocol); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index ff292d3f2c41..de6390365c90 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -62,6 +62,7 @@ struct rtnl_link { rtnl_doit_func doit; rtnl_dumpit_func dumpit; + struct module *owner; unsigned int flags; struct rcu_head rcu; }; @@ -129,7 +130,6 @@ EXPORT_SYMBOL(lockdep_rtnl_is_held); #endif /* #ifdef CONFIG_PROVE_LOCKING */ static struct rtnl_link __rcu **rtnl_msg_handlers[RTNL_FAMILY_MAX + 1]; -static refcount_t rtnl_msg_handlers_ref[RTNL_FAMILY_MAX + 1]; static inline int rtm_msgindex(int msgtype) { @@ -159,27 +159,10 @@ static struct rtnl_link *rtnl_get_link(int protocol, int msgtype) return tab[msgtype]; } -/** - * __rtnl_register - Register a rtnetlink message type - * @protocol: Protocol family or PF_UNSPEC - * @msgtype: rtnetlink message type - * @doit: Function pointer called for each request message - * @dumpit: Function pointer called for each dump request (NLM_F_DUMP) message - * @flags: rtnl_link_flags to modifiy behaviour of doit/dumpit functions - * - * Registers the specified function pointers (at least one of them has - * to be non-NULL) to be called whenever a request message for the - * specified protocol family and message type is received. - * - * The special protocol family PF_UNSPEC may be used to define fallback - * function pointers for the case when no entry for the specific protocol - * family exists. - * - * Returns 0 on success or a negative error code. - */ -int __rtnl_register(int protocol, int msgtype, - rtnl_doit_func doit, rtnl_dumpit_func dumpit, - unsigned int flags) +static int rtnl_register_internal(struct module *owner, + int protocol, int msgtype, + rtnl_doit_func doit, rtnl_dumpit_func dumpit, + unsigned int flags) { struct rtnl_link **tab, *link, *old; int msgindex; @@ -210,6 +193,9 @@ int __rtnl_register(int protocol, int msgtype, goto unlock; } + WARN_ON(link->owner && link->owner != owner); + link->owner = owner; + WARN_ON(doit && link->doit && link->doit != doit); if (doit) link->doit = doit; @@ -228,6 +214,54 @@ unlock: rtnl_unlock(); return ret; } + +/** + * rtnl_register_module - Register a rtnetlink message type + * + * @owner: module registering the hook (THIS_MODULE) + * @protocol: Protocol family or PF_UNSPEC + * @msgtype: rtnetlink message type + * @doit: Function pointer called for each request message + * @dumpit: Function pointer called for each dump request (NLM_F_DUMP) message + * @flags: rtnl_link_flags to modifiy behaviour of doit/dumpit functions + * + * Like rtnl_register, but for use by removable modules. + */ +int rtnl_register_module(struct module *owner, + int protocol, int msgtype, + rtnl_doit_func doit, rtnl_dumpit_func dumpit, + unsigned int flags) +{ + return rtnl_register_internal(owner, protocol, msgtype, + doit, dumpit, flags); +} +EXPORT_SYMBOL_GPL(rtnl_register_module); + +/** + * __rtnl_register - Register a rtnetlink message type + * @protocol: Protocol family or PF_UNSPEC + * @msgtype: rtnetlink message type + * @doit: Function pointer called for each request message + * @dumpit: Function pointer called for each dump request (NLM_F_DUMP) message + * @flags: rtnl_link_flags to modifiy behaviour of doit/dumpit functions + * + * Registers the specified function pointers (at least one of them has + * to be non-NULL) to be called whenever a request message for the + * specified protocol family and message type is received. + * + * The special protocol family PF_UNSPEC may be used to define fallback + * function pointers for the case when no entry for the specific protocol + * family exists. + * + * Returns 0 on success or a negative error code. + */ +int __rtnl_register(int protocol, int msgtype, + rtnl_doit_func doit, rtnl_dumpit_func dumpit, + unsigned int flags) +{ + return rtnl_register_internal(NULL, protocol, msgtype, + doit, dumpit, flags); +} EXPORT_SYMBOL_GPL(__rtnl_register); /** @@ -311,8 +345,6 @@ void rtnl_unregister_all(int protocol) synchronize_net(); - while (refcount_read(&rtnl_msg_handlers_ref[protocol]) > 1) - schedule(); kfree(tab); } EXPORT_SYMBOL_GPL(rtnl_unregister_all); @@ -4372,6 +4404,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, { struct net *net = sock_net(skb->sk); struct rtnl_link *link; + struct module *owner; int err = -EOPNOTSUPP; rtnl_doit_func doit; unsigned int flags; @@ -4408,24 +4441,32 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, if (!link || !link->dumpit) goto err_unlock; } + owner = link->owner; dumpit = link->dumpit; - refcount_inc(&rtnl_msg_handlers_ref[family]); - if (type == RTM_GETLINK - RTM_BASE) min_dump_alloc = rtnl_calcit(skb, nlh); + err = 0; + /* need to do this before rcu_read_unlock() */ + if (!try_module_get(owner)) + err = -EPROTONOSUPPORT; + rcu_read_unlock(); rtnl = net->rtnl; - { + if (err == 0) { struct netlink_dump_control c = { .dump = dumpit, .min_dump_alloc = min_dump_alloc, + .module = owner, }; err = netlink_dump_start(rtnl, skb, nlh, &c); + /* netlink_dump_start() will keep a reference on + * module if dump is still in progress. + */ + module_put(owner); } - refcount_dec(&rtnl_msg_handlers_ref[family]); return err; } @@ -4437,14 +4478,19 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, goto out_unlock; } + owner = link->owner; + if (!try_module_get(owner)) { + err = -EPROTONOSUPPORT; + goto out_unlock; + } + flags = link->flags; if (flags & RTNL_FLAG_DOIT_UNLOCKED) { - refcount_inc(&rtnl_msg_handlers_ref[family]); doit = link->doit; rcu_read_unlock(); if (doit) err = doit(skb, nlh, extack); - refcount_dec(&rtnl_msg_handlers_ref[family]); + module_put(owner); return err; } rcu_read_unlock(); @@ -4455,6 +4501,8 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, err = link->doit(skb, nlh, extack); rtnl_unlock(); + module_put(owner); + return err; out_unlock: @@ -4546,11 +4594,6 @@ static struct pernet_operations rtnetlink_net_ops = { void __init rtnetlink_init(void) { - int i; - - for (i = 0; i < ARRAY_SIZE(rtnl_msg_handlers_ref); i++) - refcount_set(&rtnl_msg_handlers_ref[i], 1); - if (register_pernet_subsys(&rtnetlink_net_ops)) panic("rtnetlink_init: cannot initialize rtnetlink\n"); |