+/*
+ * kauditd_send_multicast_skb - send the skb to multicast userspace listeners
+ *
+ * This function doesn't consume an skb as might be expected since it has to
+ * copy it anyways.
+ */
+static void kauditd_send_multicast_skb(struct sk_buff *skb)
+{
+ struct sk_buff *copy;
+ struct audit_net *aunet = net_generic(&init_net, audit_net_id);
+ struct sock *sock = aunet->nlsk;
+
+ if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
+ return;
+
+ /*
+ * The seemingly wasteful skb_copy() rather than bumping the refcount
+ * using skb_get() is necessary because non-standard mods are made to
+ * the skb by the original kaudit unicast socket send routine. The
+ * existing auditd daemon assumes this breakage. Fixing this would
+ * require co-ordinating a change in the established protocol between
+ * the kaudit kernel subsystem and the auditd userspace code. There is
+ * no reason for new multicast clients to continue with this
+ * non-compliance.
+ */
+ copy = skb_copy(skb, GFP_KERNEL);
+ if (!copy)
+ return;
+
+ nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
+}
+