1 files changed, 72 insertions, 16 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 3ae3cb816563..8b6bbb3032b0 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -85,6 +85,8 @@ struct netlink_sock {
 
 #define NETLINK_KERNEL_SOCKET   0x1
 #define NETLINK_RECV_PKTINFO    0x2
+#define NETLINK_BROADCAST_SEND_ERROR    0x4
+#define NETLINK_RECV_NO_ENOBUFS 0x8
 
 static inline struct netlink_sock *nlk_sk(struct sock *sk)
 {
@@ -716,10 +718,15 @@ static int netlink_getname(struct socket *sock, struct sockaddr *addr,
 
 static void netlink_overrun(struct sock *sk)
 {
-        if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
-                sk->sk_err = ENOBUFS;
-                sk->sk_error_report(sk);
+        struct netlink_sock *nlk = nlk_sk(sk);
+
+        if (!(nlk->flags & NETLINK_RECV_NO_ENOBUFS)) {
+                if (!test_and_set_bit(0, &nlk_sk(sk)->state)) {
+                        sk->sk_err = ENOBUFS;
+                        sk->sk_error_report(sk);
+                }
         }
+        atomic_inc(&sk->sk_drops);
 }
 
 static struct sock *netlink_getsockbypid(struct sock *ssk, u32 pid)
@@ -950,6 +957,7 @@ struct netlink_broadcast_data {
         u32 pid;
         u32 group;
         int failure;
+        int delivery_failure;
         int congested;
         int delivered;
         gfp_t allocation;
@@ -994,11 +1002,15 @@ static inline int do_one_broadcast(struct sock *sk,
                 netlink_overrun(sk);
                 /* Clone failed. Notify ALL listeners. */
                 p->failure = 1;
+                if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
+                        p->delivery_failure = 1;
         } else if (sk_filter(sk, p->skb2)) {
                 kfree_skb(p->skb2);
                 p->skb2 = NULL;
         } else if ((val = netlink_broadcast_deliver(sk, p->skb2)) < 0) {
                 netlink_overrun(sk);
+                if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
+                        p->delivery_failure = 1;
         } else {
                 p->congested |= val;
                 p->delivered = 1;
@@ -1025,6 +1037,7 @@ int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
         info.pid = pid;
         info.group = group;
         info.failure = 0;
+        info.delivery_failure = 0;
         info.congested = 0;
         info.delivered = 0;
         info.allocation = allocation;
@@ -1042,16 +1055,16 @@ int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
 
         netlink_unlock_table();
 
-        if (info.skb2)
-                kfree_skb(info.skb2);
+        kfree_skb(info.skb2);
+
+        if (info.delivery_failure)
+                return -ENOBUFS;
 
         if (info.delivered) {
                 if (info.congested && (allocation & __GFP_WAIT))
                         yield();
                 return 0;
         }
-        if (info.failure)
-                return -ENOBUFS;
         return -ESRCH;
 }
 EXPORT_SYMBOL(netlink_broadcast);
@@ -1110,6 +1123,7 @@ void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code)
 
         read_unlock(&nl_table_lock);
 }
+EXPORT_SYMBOL(netlink_set_err);
 
 /* must be called with netlink table grabbed */
 static void netlink_update_socket_mc(struct netlink_sock *nlk,
@@ -1167,6 +1181,22 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname,
                 err = 0;
                 break;
         }
+        case NETLINK_BROADCAST_ERROR:
+                if (val)
+                        nlk->flags |= NETLINK_BROADCAST_SEND_ERROR;
+                else
+                        nlk->flags &= ~NETLINK_BROADCAST_SEND_ERROR;
+                err = 0;
+                break;
+        case NETLINK_NO_ENOBUFS:
+                if (val) {
+                        nlk->flags |= NETLINK_RECV_NO_ENOBUFS;
+                        clear_bit(0, &nlk->state);
+                        wake_up_interruptible(&nlk->wait);
+                } else
+                        nlk->flags &= ~NETLINK_RECV_NO_ENOBUFS;
+                err = 0;
+                break;
         default:
                 err = -ENOPROTOOPT;
         }
@@ -1199,6 +1229,26 @@ static int netlink_getsockopt(struct socket *sock, int level, int optname,
                         return -EFAULT;
                 err = 0;
                 break;
+        case NETLINK_BROADCAST_ERROR:
+                if (len < sizeof(int))
+                        return -EINVAL;
+                len = sizeof(int);
+                val = nlk->flags & NETLINK_BROADCAST_SEND_ERROR ? 1 : 0;
+                if (put_user(len, optlen) ||
+                    put_user(val, optval))
+                        return -EFAULT;
+                err = 0;
+                break;
+        case NETLINK_NO_ENOBUFS:
+                if (len < sizeof(int))
+                        return -EINVAL;
+                len = sizeof(int);
+                val = nlk->flags & NETLINK_RECV_NO_ENOBUFS ? 1 : 0;
+                if (put_user(len, optlen) ||
+                    put_user(val, optval))
+                        return -EFAULT;
+                err = 0;
+                break;
         default:
                 err = -ENOPROTOOPT;
         }
@@ -1525,8 +1575,7 @@ EXPORT_SYMBOL(netlink_set_nonroot);
 
 static void netlink_destroy_callback(struct netlink_callback *cb)
 {
-        if (cb->skb)
-                kfree_skb(cb->skb);
+        kfree_skb(cb->skb);
         kfree(cb);
 }
 
@@ -1743,12 +1792,18 @@ int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 pid,
                         exclude_pid = pid;
                 }
 
-                /* errors reported via destination sk->sk_err */
-                nlmsg_multicast(sk, skb, exclude_pid, group, flags);
+                /* errors reported via destination sk->sk_err, but propagate
+                 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
+                err = nlmsg_multicast(sk, skb, exclude_pid, group, flags);
         }
 
-        if (report)
-                err = nlmsg_unicast(sk, skb, pid);
+        if (report) {
+                int err2;
+
+                err2 = nlmsg_unicast(sk, skb, pid);
+                if (!err || err == -ESRCH)
+                        err = err2;
+        }
 
         return err;
 }
@@ -1849,12 +1904,12 @@ static int netlink_seq_show(struct seq_file *seq, void *v)
         if (v == SEQ_START_TOKEN)
                 seq_puts(seq,
                          "sk       Eth Pid    Groups   "
-                         "Rmem     Wmem     Dump     Locks\n");
+                         "Rmem     Wmem     Dump     Locks     Drops\n");
         else {
                 struct sock *s = v;
                 struct netlink_sock *nlk = nlk_sk(s);
 
-                seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %d\n",
+                seq_printf(seq, "%p %-3d %-6d %08x %-8d %-8d %p %-8d %-8d\n",
                            s,
                            s->sk_protocol,
                            nlk->pid,
@@ -1862,7 +1917,8 @@ static int netlink_seq_show(struct seq_file *seq, void *v)
                            atomic_read(&s->sk_rmem_alloc),
                            atomic_read(&s->sk_wmem_alloc),
                            nlk->cb,
-                           atomic_read(&s->sk_refcnt)
+                           atomic_read(&s->sk_refcnt),
+                           atomic_read(&s->sk_drops)
                         );
 
         }