diff options
Diffstat (limited to 'net/netlink/af_netlink.c')
| -rw-r--r-- | net/netlink/af_netlink.c | 59 |
1 files changed, 42 insertions, 17 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index a774985489e2..50889be1517d 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -84,6 +84,7 @@ struct listeners { #define NETLINK_F_BROADCAST_SEND_ERROR 0x4 #define NETLINK_F_RECV_NO_ENOBUFS 0x8 #define NETLINK_F_LISTEN_ALL_NSID 0x10 +#define NETLINK_F_CAP_ACK 0x20 static inline int netlink_is_kernel(struct sock *sk) { @@ -593,16 +594,6 @@ netlink_current_frame(const struct netlink_ring *ring, return netlink_lookup_frame(ring, ring->head, status); } -static struct nl_mmap_hdr * -netlink_previous_frame(const struct netlink_ring *ring, - enum nl_mmap_status status) -{ - unsigned int prev; - - prev = ring->head ? ring->head - 1 : ring->frame_max; - return netlink_lookup_frame(ring, prev, status); -} - static void netlink_increment_head(struct netlink_ring *ring) { ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0; @@ -610,11 +601,11 @@ static void netlink_increment_head(struct netlink_ring *ring) static void netlink_forward_ring(struct netlink_ring *ring) { - unsigned int head = ring->head, pos = head; + unsigned int head = ring->head; const struct nl_mmap_hdr *hdr; do { - hdr = __netlink_lookup_frame(ring, pos); + hdr = __netlink_lookup_frame(ring, ring->head); if (hdr->nm_status == NL_MMAP_STATUS_UNUSED) break; if (hdr->nm_status != NL_MMAP_STATUS_SKIP) @@ -623,6 +614,21 @@ static void netlink_forward_ring(struct netlink_ring *ring) } while (ring->head != head); } +static bool netlink_has_valid_frame(struct netlink_ring *ring) +{ + unsigned int head = ring->head, pos = head; + const struct nl_mmap_hdr *hdr; + + do { + hdr = __netlink_lookup_frame(ring, pos); + if (hdr->nm_status == NL_MMAP_STATUS_VALID) + return true; + pos = pos != 0 ? pos - 1 : ring->frame_max; + } while (pos != head); + + return false; +} + static bool netlink_dump_space(struct netlink_sock *nlk) { struct netlink_ring *ring = &nlk->rx_ring; @@ -670,8 +676,7 @@ static unsigned int netlink_poll(struct file *file, struct socket *sock, spin_lock_bh(&sk->sk_receive_queue.lock); if (nlk->rx_ring.pg_vec) { - netlink_forward_ring(&nlk->rx_ring); - if (!netlink_previous_frame(&nlk->rx_ring, NL_MMAP_STATUS_UNUSED)) + if (netlink_has_valid_frame(&nlk->rx_ring)) mask |= POLLIN | POLLRDNORM; } spin_unlock_bh(&sk->sk_receive_queue.lock); @@ -2258,6 +2263,13 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname, nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID; err = 0; break; + case NETLINK_CAP_ACK: + if (val) + nlk->flags |= NETLINK_F_CAP_ACK; + else + nlk->flags &= ~NETLINK_F_CAP_ACK; + err = 0; + break; default: err = -ENOPROTOOPT; } @@ -2332,6 +2344,16 @@ static int netlink_getsockopt(struct socket *sock, int level, int optname, netlink_table_ungrab(); break; } + case NETLINK_CAP_ACK: + if (len < sizeof(int)) + return -EINVAL; + len = sizeof(int); + val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0; + if (put_user(len, optlen) || + put_user(val, optval)) + return -EFAULT; + err = 0; + break; default: err = -ENOPROTOOPT; } @@ -2873,9 +2895,12 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) struct nlmsghdr *rep; struct nlmsgerr *errmsg; size_t payload = sizeof(*errmsg); + struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk); - /* error messages get the original request appened */ - if (err) + /* Error messages get the original request appened, unless the user + * requests to cap the error message. + */ + if (!(nlk->flags & NETLINK_F_CAP_ACK) && err) payload += nlmsg_len(nlh); skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload), @@ -2898,7 +2923,7 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) NLMSG_ERROR, payload, 0); errmsg = nlmsg_data(rep); errmsg->error = err; - memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh)); + memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh)); netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT); } EXPORT_SYMBOL(netlink_ack); |