diff options
| -rw-r--r-- | include/linux/netlink.h | 10 | ||||
| -rw-r--r-- | net/netlink/af_netlink.c | 107 |
2 files changed, 117 insertions, 0 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h index f78b430..86fde81a 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -145,4 +145,14 @@ static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, return __netlink_dump_start(ssk, skb, nlh, control); } +struct netlink_tap { + struct net_device *dev; + struct module *module; + struct list_head list; +}; + +extern int netlink_add_tap(struct netlink_tap *nt); +extern int __netlink_remove_tap(struct netlink_tap *nt); +extern int netlink_remove_tap(struct netlink_tap *nt); + #endif /* __LINUX_NETLINK_H */ diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 275d901..6967fbc 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -57,6 +57,7 @@ #include <linux/audit.h> #include <linux/mutex.h> #include <linux/vmalloc.h> +#include <linux/if_arp.h> #include <asm/cacheflush.h> #include <net/net_namespace.h> @@ -101,6 +102,9 @@ static atomic_t nl_table_users = ATOMIC_INIT(0); static ATOMIC_NOTIFIER_HEAD(netlink_chain); +static DEFINE_SPINLOCK(netlink_tap_lock); +static struct list_head netlink_tap_all __read_mostly; + static inline u32 netlink_group_mask(u32 group) { return group ? 1 << (group - 1) : 0; @@ -111,6 +115,100 @@ static inline struct hlist_head *nl_portid_hashfn(struct nl_portid_hash *hash, u return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask]; } +int netlink_add_tap(struct netlink_tap *nt) +{ + if (unlikely(nt->dev->type != ARPHRD_NETLINK)) + return -EINVAL; + + spin_lock(&netlink_tap_lock); + list_add_rcu(&nt->list, &netlink_tap_all); + spin_unlock(&netlink_tap_lock); + + if (nt->module) + __module_get(nt->module); + + return 0; +} +EXPORT_SYMBOL_GPL(netlink_add_tap); + +int __netlink_remove_tap(struct netlink_tap *nt) +{ + bool found = false; + struct netlink_tap *tmp; + + spin_lock(&netlink_tap_lock); + + list_for_each_entry(tmp, &netlink_tap_all, list) { + if (nt == tmp) { + list_del_rcu(&nt->list); + found = true; + goto out; + } + } + + pr_warn("__netlink_remove_tap: %p not found\n", nt); +out: + spin_unlock(&netlink_tap_lock); + + if (found && nt->module) + module_put(nt->module); + + return found ? 0 : -ENODEV; +} +EXPORT_SYMBOL_GPL(__netlink_remove_tap); + +int netlink_remove_tap(struct netlink_tap *nt) +{ + int ret; + + ret = __netlink_remove_tap(nt); + synchronize_net(); + + return ret; +} +EXPORT_SYMBOL_GPL(netlink_remove_tap); + +static int __netlink_deliver_tap_skb(struct sk_buff *skb, + struct net_device *dev) +{ + struct sk_buff *nskb; + int ret = -ENOMEM; + + dev_hold(dev); + nskb = skb_clone(skb, GFP_ATOMIC); + if (nskb) { + nskb->dev = dev; + ret = dev_queue_xmit(nskb); + if (unlikely(ret > 0)) + ret = net_xmit_errno(ret); + } + + dev_put(dev); + return ret; +} + +static void __netlink_deliver_tap(struct sk_buff *skb) +{ + int ret; + struct netlink_tap *tmp; + + list_for_each_entry_rcu(tmp, &netlink_tap_all, list) { + ret = __netlink_deliver_tap_skb(skb, tmp->dev); + if (unlikely(ret)) + break; + } +} + +static void netlink_deliver_tap(struct sk_buff *skb) +{ + rcu_read_lock(); + + if (unlikely(!list_empty(&netlink_tap_all))) + __netlink_deliver_tap(skb); + + rcu_read_unlock(); +} + static void netlink_overrun(struct sock *sk) { struct netlink_sock *nlk = nlk_sk(sk); @@ -1518,6 +1616,8 @@ static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb) { int len = skb->len; + netlink_deliver_tap(skb); + #ifdef CONFIG_NETLINK_MMAP if (netlink_skb_is_mmaped(skb)) netlink_queue_mmaped_skb(sk, skb); @@ -1578,6 +1678,11 @@ static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb, ret = -ECONNREFUSED; if (nlk->netlink_rcv != NULL) { + /* We could do a netlink_deliver_tap(skb) here as well + * but since this is intended for the kernel only, we + * should rather let it stay under the hood. + */ + ret = skb->len; netlink_skb_set_owner_r(skb, sk); NETLINK_CB(skb).sk = ssk; @@ -2975,6 +3080,8 @@ static int __init netlink_proto_init(void) nl_table[i].compare = netlink_compare; } + INIT_LIST_HEAD(&netlink_tap_all); + netlink_add_usersock_entry(); sock_register(&netlink_family_ops); |
