diff options
| -rw-r--r-- | include/linux/netlink.h | 2 | ||||
| -rw-r--r-- | net/netlink/af_netlink.c | 144 |
2 files changed, 143 insertions, 3 deletions
diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 07c4738..6358da5 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -64,6 +64,8 @@ extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group) extern void netlink_clear_multicast_users(struct sock *sk, unsigned int group); extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err); extern int netlink_has_listeners(struct sock *sk, unsigned int group); +extern struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size, + u32 dst_portid, gfp_t gfp_mask); extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock); extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid, __u32 group, gfp_t allocation); diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 90504a0..d120b5d 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -116,6 +116,11 @@ static bool netlink_skb_is_mmaped(const struct sk_buff *skb) return NETLINK_CB(skb).flags & NETLINK_SKB_MMAPED; } +static bool netlink_rx_is_mmaped(struct sock *sk) +{ + return nlk_sk(sk)->rx_ring.pg_vec != NULL; +} + static bool netlink_tx_is_mmaped(struct sock *sk) { return nlk_sk(sk)->tx_ring.pg_vec != NULL; @@ -589,8 +594,54 @@ out: mutex_unlock(&nlk->pg_vec_lock); return err; } + +static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb) +{ + struct nl_mmap_hdr *hdr; + + hdr = netlink_mmap_hdr(skb); + hdr->nm_len = skb->len; + hdr->nm_group = NETLINK_CB(skb).dst_group; + hdr->nm_pid = NETLINK_CB(skb).creds.pid; + hdr->nm_uid = NETLINK_CB(skb).creds.uid; + hdr->nm_gid = NETLINK_CB(skb).creds.gid; + netlink_frame_flush_dcache(hdr); + netlink_set_status(hdr, NL_MMAP_STATUS_VALID); + + NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED; + kfree_skb(skb); +} + +static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb) +{ + struct netlink_sock *nlk = nlk_sk(sk); + struct netlink_ring *ring = &nlk->rx_ring; + struct nl_mmap_hdr *hdr; + + spin_lock_bh(&sk->sk_receive_queue.lock); + hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED); + if (hdr == NULL) { + spin_unlock_bh(&sk->sk_receive_queue.lock); + kfree_skb(skb); + sk->sk_err = ENOBUFS; + sk->sk_error_report(sk); + return; + } + netlink_increment_head(ring); + __skb_queue_tail(&sk->sk_receive_queue, skb); + spin_unlock_bh(&sk->sk_receive_queue.lock); + + hdr->nm_len = skb->len; + hdr->nm_group = NETLINK_CB(skb).dst_group; + hdr->nm_pid = NETLINK_CB(skb).creds.pid; + hdr->nm_uid = NETLINK_CB(skb).creds.uid; + hdr->nm_gid = NETLINK_CB(skb).creds.gid; + netlink_set_status(hdr, NL_MMAP_STATUS_COPY); +} + #else /* CONFIG_NETLINK_MMAP */ #define netlink_skb_is_mmaped(skb) false +#define netlink_rx_is_mmaped(sk) false #define netlink_tx_is_mmaped(sk) false #define netlink_mmap sock_no_mmap #define netlink_poll datagram_poll @@ -1381,7 +1432,14 @@ static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb) { int len = skb->len; - skb_queue_tail(&sk->sk_receive_queue, skb); +#ifdef CONFIG_NETLINK_MMAP + if (netlink_skb_is_mmaped(skb)) + netlink_queue_mmaped_skb(sk, skb); + else if (netlink_rx_is_mmaped(sk)) + netlink_ring_set_copied(sk, skb); + else +#endif /* CONFIG_NETLINK_MMAP */ + skb_queue_tail(&sk->sk_receive_queue, skb); sk->sk_data_ready(sk, len); return len; } @@ -1492,6 +1550,68 @@ retry: } EXPORT_SYMBOL(netlink_unicast); +struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size, + u32 dst_portid, gfp_t gfp_mask) +{ +#ifdef CONFIG_NETLINK_MMAP + struct sock *sk = NULL; + struct sk_buff *skb; + struct netlink_ring *ring; + struct nl_mmap_hdr *hdr; + unsigned int maxlen; + + sk = netlink_getsockbyportid(ssk, dst_portid); + if (IS_ERR(sk)) + goto out; + + ring = &nlk_sk(sk)->rx_ring; + /* fast-path without atomic ops for common case: non-mmaped receiver */ + if (ring->pg_vec == NULL) + goto out_put; + + skb = alloc_skb_head(gfp_mask); + if (skb == NULL) + goto err1; + + spin_lock_bh(&sk->sk_receive_queue.lock); + /* check again under lock */ + if (ring->pg_vec == NULL) + goto out_free; + + maxlen = ring->frame_size - NL_MMAP_HDRLEN; + if (maxlen < size) + goto out_free; + + netlink_forward_ring(ring); + hdr = netlink_current_frame(ring, NL_MMAP_STATUS_UNUSED); + if (hdr == NULL) + goto err2; + netlink_ring_setup_skb(skb, sk, ring, hdr); + netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED); + atomic_inc(&ring->pending); + netlink_increment_head(ring); + + spin_unlock_bh(&sk->sk_receive_queue.lock); + return skb; + +err2: + kfree_skb(skb); + spin_unlock_bh(&sk->sk_receive_queue.lock); +err1: + sock_put(sk); + return NULL; + +out_free: + kfree_skb(skb); + spin_unlock_bh(&sk->sk_receive_queue.lock); +out_put: + sock_put(sk); +out: +#endif + return alloc_skb(size, gfp_mask); +} +EXPORT_SYMBOL_GPL(netlink_alloc_skb); + int netlink_has_listeners(struct sock *sk, unsigned int group) { int res = 0; @@ -2270,9 +2390,13 @@ static int netlink_dump(struct sock *sk) alloc_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); - skb = sock_rmalloc(sk, alloc_size, 0, GFP_KERNEL); + if (!netlink_rx_is_mmaped(sk) && + atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) + goto errout_skb; + skb = netlink_alloc_skb(sk, alloc_size, nlk->portid, GFP_KERNEL); if (!skb) goto errout_skb; + netlink_skb_set_owner_r(skb, sk); len = cb->dump(skb, cb); @@ -2327,6 +2451,19 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, if (cb == NULL) return -ENOBUFS; + /* Memory mapped dump requests need to be copied to avoid looping + * on the pending state in netlink_mmap_sendmsg() while the CB hold + * a reference to the skb. + */ + if (netlink_skb_is_mmaped(skb)) { + skb = skb_copy(skb, GFP_KERNEL); + if (skb == NULL) { + kfree(cb); + return -ENOBUFS; + } + } else + atomic_inc(&skb->users); + cb->dump = control->dump; cb->done = control->done; cb->nlh = nlh; @@ -2387,7 +2524,8 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) if (err) payload += nlmsg_len(nlh); - skb = nlmsg_new(payload, GFP_KERNEL); + skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload), + NETLINK_CB(in_skb).portid, GFP_KERNEL); if (!skb) { struct sock *sk; |