diff options
| -rw-r--r-- | net/core/rtnetlink.c | 154 |
1 files changed, 101 insertions, 53 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index dabba2a91fc8..ff292d3f2c41 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -63,6 +63,7 @@ struct rtnl_link { rtnl_doit_func doit; rtnl_dumpit_func dumpit; unsigned int flags; + struct rcu_head rcu; }; static DEFINE_MUTEX(rtnl_mutex); @@ -127,7 +128,7 @@ bool lockdep_rtnl_is_held(void) EXPORT_SYMBOL(lockdep_rtnl_is_held); #endif /* #ifdef CONFIG_PROVE_LOCKING */ -static struct rtnl_link __rcu *rtnl_msg_handlers[RTNL_FAMILY_MAX + 1]; +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) @@ -144,6 +145,20 @@ static inline int rtm_msgindex(int msgtype) return msgindex; } +static struct rtnl_link *rtnl_get_link(int protocol, int msgtype) +{ + struct rtnl_link **tab; + + if (protocol >= ARRAY_SIZE(rtnl_msg_handlers)) + protocol = PF_UNSPEC; + + tab = rcu_dereference_rtnl(rtnl_msg_handlers[protocol]); + if (!tab) + tab = rcu_dereference_rtnl(rtnl_msg_handlers[PF_UNSPEC]); + + return tab[msgtype]; +} + /** * __rtnl_register - Register a rtnetlink message type * @protocol: Protocol family or PF_UNSPEC @@ -166,28 +181,52 @@ int __rtnl_register(int protocol, int msgtype, rtnl_doit_func doit, rtnl_dumpit_func dumpit, unsigned int flags) { - struct rtnl_link *tab; + struct rtnl_link **tab, *link, *old; int msgindex; + int ret = -ENOBUFS; BUG_ON(protocol < 0 || protocol > RTNL_FAMILY_MAX); msgindex = rtm_msgindex(msgtype); - tab = rcu_dereference_raw(rtnl_msg_handlers[protocol]); + rtnl_lock(); + tab = rtnl_msg_handlers[protocol]; if (tab == NULL) { - tab = kcalloc(RTM_NR_MSGTYPES, sizeof(*tab), GFP_KERNEL); - if (tab == NULL) - return -ENOBUFS; + tab = kcalloc(RTM_NR_MSGTYPES, sizeof(void *), GFP_KERNEL); + if (!tab) + goto unlock; + /* ensures we see the 0 stores */ rcu_assign_pointer(rtnl_msg_handlers[protocol], tab); } + old = rtnl_dereference(tab[msgindex]); + if (old) { + link = kmemdup(old, sizeof(*old), GFP_KERNEL); + if (!link) + goto unlock; + } else { + link = kzalloc(sizeof(*link), GFP_KERNEL); + if (!link) + goto unlock; + } + + WARN_ON(doit && link->doit && link->doit != doit); if (doit) - tab[msgindex].doit = doit; + link->doit = doit; + WARN_ON(dumpit && link->dumpit && link->dumpit != dumpit); if (dumpit) - tab[msgindex].dumpit = dumpit; - tab[msgindex].flags |= flags; + link->dumpit = dumpit; - return 0; + link->flags |= flags; + + /* publish protocol:msgtype */ + rcu_assign_pointer(tab[msgindex], link); + ret = 0; + if (old) + kfree_rcu(old, rcu); +unlock: + rtnl_unlock(); + return ret; } EXPORT_SYMBOL_GPL(__rtnl_register); @@ -220,24 +259,25 @@ EXPORT_SYMBOL_GPL(rtnl_register); */ int rtnl_unregister(int protocol, int msgtype) { - struct rtnl_link *handlers; + struct rtnl_link **tab, *link; int msgindex; BUG_ON(protocol < 0 || protocol > RTNL_FAMILY_MAX); msgindex = rtm_msgindex(msgtype); rtnl_lock(); - handlers = rtnl_dereference(rtnl_msg_handlers[protocol]); - if (!handlers) { + tab = rtnl_dereference(rtnl_msg_handlers[protocol]); + if (!tab) { rtnl_unlock(); return -ENOENT; } - handlers[msgindex].doit = NULL; - handlers[msgindex].dumpit = NULL; - handlers[msgindex].flags = 0; + link = tab[msgindex]; + rcu_assign_pointer(tab[msgindex], NULL); rtnl_unlock(); + kfree_rcu(link, rcu); + return 0; } EXPORT_SYMBOL_GPL(rtnl_unregister); @@ -251,20 +291,29 @@ EXPORT_SYMBOL_GPL(rtnl_unregister); */ void rtnl_unregister_all(int protocol) { - struct rtnl_link *handlers; + struct rtnl_link **tab, *link; + int msgindex; BUG_ON(protocol < 0 || protocol > RTNL_FAMILY_MAX); rtnl_lock(); - handlers = rtnl_dereference(rtnl_msg_handlers[protocol]); + tab = rtnl_msg_handlers[protocol]; RCU_INIT_POINTER(rtnl_msg_handlers[protocol], NULL); + for (msgindex = 0; msgindex < RTM_NR_MSGTYPES; msgindex++) { + link = tab[msgindex]; + if (!link) + continue; + + rcu_assign_pointer(tab[msgindex], NULL); + kfree_rcu(link, rcu); + } rtnl_unlock(); synchronize_net(); while (refcount_read(&rtnl_msg_handlers_ref[protocol]) > 1) schedule(); - kfree(handlers); + kfree(tab); } EXPORT_SYMBOL_GPL(rtnl_unregister_all); @@ -2973,18 +3022,26 @@ static int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb) s_idx = 1; for (idx = 1; idx <= RTNL_FAMILY_MAX; idx++) { + struct rtnl_link **tab; int type = cb->nlh->nlmsg_type-RTM_BASE; - struct rtnl_link *handlers; + struct rtnl_link *link; rtnl_dumpit_func dumpit; if (idx < s_idx || idx == PF_PACKET) continue; - handlers = rtnl_dereference(rtnl_msg_handlers[idx]); - if (!handlers) + if (type < 0 || type >= RTM_NR_MSGTYPES) continue; - dumpit = READ_ONCE(handlers[type].dumpit); + tab = rcu_dereference_rtnl(rtnl_msg_handlers[idx]); + if (!tab) + continue; + + link = tab[type]; + if (!link) + continue; + + dumpit = link->dumpit; if (!dumpit) continue; @@ -4314,7 +4371,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, struct netlink_ext_ack *extack) { struct net *net = sock_net(skb->sk); - struct rtnl_link *handlers; + struct rtnl_link *link; int err = -EOPNOTSUPP; rtnl_doit_func doit; unsigned int flags; @@ -4338,32 +4395,20 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, if (kind != 2 && !netlink_net_capable(skb, CAP_NET_ADMIN)) return -EPERM; - if (family >= ARRAY_SIZE(rtnl_msg_handlers)) - family = PF_UNSPEC; - rcu_read_lock(); - handlers = rcu_dereference(rtnl_msg_handlers[family]); - if (!handlers) { - family = PF_UNSPEC; - handlers = rcu_dereference(rtnl_msg_handlers[family]); - } - if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) { struct sock *rtnl; rtnl_dumpit_func dumpit; u16 min_dump_alloc = 0; - dumpit = READ_ONCE(handlers[type].dumpit); - if (!dumpit) { + link = rtnl_get_link(family, type); + if (!link || !link->dumpit) { family = PF_UNSPEC; - handlers = rcu_dereference(rtnl_msg_handlers[PF_UNSPEC]); - if (!handlers) - goto err_unlock; - - dumpit = READ_ONCE(handlers[type].dumpit); - if (!dumpit) + link = rtnl_get_link(family, type); + if (!link || !link->dumpit) goto err_unlock; } + dumpit = link->dumpit; refcount_inc(&rtnl_msg_handlers_ref[family]); @@ -4384,33 +4429,36 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, return err; } - doit = READ_ONCE(handlers[type].doit); - if (!doit) { + link = rtnl_get_link(family, type); + if (!link || !link->doit) { family = PF_UNSPEC; - handlers = rcu_dereference(rtnl_msg_handlers[family]); + link = rtnl_get_link(PF_UNSPEC, type); + if (!link || !link->doit) + goto out_unlock; } - flags = READ_ONCE(handlers[type].flags); + flags = link->flags; if (flags & RTNL_FLAG_DOIT_UNLOCKED) { refcount_inc(&rtnl_msg_handlers_ref[family]); - doit = READ_ONCE(handlers[type].doit); + doit = link->doit; rcu_read_unlock(); if (doit) err = doit(skb, nlh, extack); refcount_dec(&rtnl_msg_handlers_ref[family]); return err; } - rcu_read_unlock(); rtnl_lock(); - handlers = rtnl_dereference(rtnl_msg_handlers[family]); - if (handlers) { - doit = READ_ONCE(handlers[type].doit); - if (doit) - err = doit(skb, nlh, extack); - } + link = rtnl_get_link(family, type); + if (link && link->doit) + err = link->doit(skb, nlh, extack); rtnl_unlock(); + + return err; + +out_unlock: + rcu_read_unlock(); return err; err_unlock: |