diff options
| -rw-r--r-- | net/packet/af_packet.c | 103 |
1 files changed, 59 insertions, 44 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 461b16f..bb281bf 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -222,6 +222,55 @@ struct packet_skb_cb { #define PACKET_SKB_CB(__skb) ((struct packet_skb_cb *)((__skb)->cb)) +static inline struct packet_sock *pkt_sk(struct sock *sk) +{ + return (struct packet_sock *)sk; +} + +/* register_prot_hook must be invoked with the po->bind_lock held, + * or from a context in which asynchronous accesses to the packet + * socket is not possible (packet_create()). + */ +static void register_prot_hook(struct sock *sk) +{ + struct packet_sock *po = pkt_sk(sk); + if (!po->running) { + dev_add_pack(&po->prot_hook); + sock_hold(sk); + po->running = 1; + } +} + +/* {,__}unregister_prot_hook() must be invoked with the po->bind_lock + * held. If the sync parameter is true, we will temporarily drop + * the po->bind_lock and do a synchronize_net to make sure no + * asynchronous packet processing paths still refer to the elements + * of po->prot_hook. If the sync parameter is false, it is the + * callers responsibility to take care of this. + */ +static void __unregister_prot_hook(struct sock *sk, bool sync) +{ + struct packet_sock *po = pkt_sk(sk); + + po->running = 0; + __dev_remove_pack(&po->prot_hook); + __sock_put(sk); + + if (sync) { + spin_unlock(&po->bind_lock); + synchronize_net(); + spin_lock(&po->bind_lock); + } +} + +static void unregister_prot_hook(struct sock *sk, bool sync) +{ + struct packet_sock *po = pkt_sk(sk); + + if (po->running) + __unregister_prot_hook(sk, sync); +} + static inline __pure struct page *pgv_to_page(void *addr) { if (is_vmalloc_addr(addr)) @@ -324,11 +373,6 @@ static inline void packet_increment_head(struct packet_ring_buffer *buff) buff->head = buff->head != buff->frame_max ? buff->head+1 : 0; } -static inline struct packet_sock *pkt_sk(struct sock *sk) -{ - return (struct packet_sock *)sk; -} - static void packet_sock_destruct(struct sock *sk) { skb_queue_purge(&sk->sk_error_queue); @@ -1337,15 +1381,7 @@ static int packet_release(struct socket *sock) spin_unlock_bh(&net->packet.sklist_lock); spin_lock(&po->bind_lock); - if (po->running) { - /* - * Remove from protocol table - */ - po->running = 0; - po->num = 0; - __dev_remove_pack(&po->prot_hook); - __sock_put(sk); - } + unregister_prot_hook(sk, false); if (po->prot_hook.dev) { dev_put(po->prot_hook.dev); po->prot_hook.dev = NULL; @@ -1392,15 +1428,7 @@ static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protoc lock_sock(sk); spin_lock(&po->bind_lock); - if (po->running) { - __sock_put(sk); - po->running = 0; - po->num = 0; - spin_unlock(&po->bind_lock); - dev_remove_pack(&po->prot_hook); - spin_lock(&po->bind_lock); - } - + unregister_prot_hook(sk, true); po->num = protocol; po->prot_hook.type = protocol; if (po->prot_hook.dev) @@ -1413,9 +1441,7 @@ static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protoc goto out_unlock; if (!dev || (dev->flags & IFF_UP)) { - dev_add_pack(&po->prot_hook); - sock_hold(sk); - po->running = 1; + register_prot_hook(sk); } else { sk->sk_err = ENETDOWN; if (!sock_flag(sk, SOCK_DEAD)) @@ -1542,9 +1568,7 @@ static int packet_create(struct net *net, struct socket *sock, int protocol, if (proto) { po->prot_hook.type = proto; - dev_add_pack(&po->prot_hook); - sock_hold(sk); - po->running = 1; + register_prot_hook(sk); } spin_lock_bh(&net->packet.sklist_lock); @@ -2240,9 +2264,7 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void if (dev->ifindex == po->ifindex) { spin_lock(&po->bind_lock); if (po->running) { - __dev_remove_pack(&po->prot_hook); - __sock_put(sk); - po->running = 0; + __unregister_prot_hook(sk, false); sk->sk_err = ENETDOWN; if (!sock_flag(sk, SOCK_DEAD)) sk->sk_error_report(sk); @@ -2259,11 +2281,8 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void case NETDEV_UP: if (dev->ifindex == po->ifindex) { spin_lock(&po->bind_lock); - if (po->num && !po->running) { - dev_add_pack(&po->prot_hook); - sock_hold(sk); - po->running = 1; - } + if (po->num) + register_prot_hook(sk); spin_unlock(&po->bind_lock); } break; @@ -2530,10 +2549,8 @@ static int packet_set_ring(struct sock *sk, struct tpacket_req *req, was_running = po->running; num = po->num; if (was_running) { - __dev_remove_pack(&po->prot_hook); po->num = 0; - po->running = 0; - __sock_put(sk); + __unregister_prot_hook(sk, false); } spin_unlock(&po->bind_lock); @@ -2564,11 +2581,9 @@ static int packet_set_ring(struct sock *sk, struct tpacket_req *req, mutex_unlock(&po->pg_vec_lock); spin_lock(&po->bind_lock); - if (was_running && !po->running) { - sock_hold(sk); - po->running = 1; + if (was_running) { po->num = num; - dev_add_pack(&po->prot_hook); + register_prot_hook(sk); } spin_unlock(&po->bind_lock); |
