@@ -110,6 +110,7 @@ struct nlmsgerr {
#define NETLINK_TX_RING 7
#define NETLINK_LISTEN_ALL_NSID 8
#define NETLINK_LIST_MEMBERSHIPS 9
+#define NETLINK_CAP_ACK 10
struct nl_pktinfo {
__u32 group;
@@ -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)
{
@@ -2258,6 +2259,13 @@ 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 +2340,16 @@ 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;
}
@@ -2869,28 +2887,33 @@ EXPORT_SYMBOL(__netlink_dump_start);
void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)
{
+ struct netlink_sock *nlk;
struct sk_buff *skb;
struct nlmsghdr *rep;
struct nlmsgerr *errmsg;
size_t payload = sizeof(*errmsg);
+ struct sock *sk;
- /* error messages get the original request appened */
- if (err)
+ sk = netlink_lookup(sock_net(in_skb->sk),
+ in_skb->sk->sk_protocol,
+ NETLINK_CB(in_skb).portid);
+ if (!sk)
+ return;
+
+ nlk = nlk_sk(sk);
+
+ /* Error messages get the original request appended, 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),
NETLINK_CB(in_skb).portid, GFP_KERNEL);
if (!skb) {
- struct sock *sk;
-
- sk = netlink_lookup(sock_net(in_skb->sk),
- in_skb->sk->sk_protocol,
- NETLINK_CB(in_skb).portid);
- if (sk) {
- sk->sk_err = ENOBUFS;
- sk->sk_error_report(sk);
- sock_put(sk);
- }
+ sk->sk_err = ENOBUFS;
+ sk->sk_error_report(sk);
+ sock_put(sk);
return;
}
@@ -2898,7 +2921,7 @@ 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);