netlink: change nlmsg_notify() return value logic
[linux-2.6.git] / net / netlink / af_netlink.c
index 98bfe27..2760b62 100644 (file)
@@ -1,7 +1,7 @@
 /*
  * NETLINK      Kernel-user communication protocol.
  *
- *             Authors:        Alan Cox <alan@redhat.com>
+ *             Authors:        Alan Cox <alan@lxorguk.ukuu.org.uk>
  *                             Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
  *
  *             This program is free software; you can redistribute it and/or
@@ -85,6 +85,7 @@ struct netlink_sock {
 
 #define NETLINK_KERNEL_SOCKET  0x1
 #define NETLINK_RECV_PKTINFO   0x2
+#define NETLINK_BROADCAST_SEND_ERROR   0x4
 
 static inline struct netlink_sock *nlk_sk(struct sock *sk)
 {
@@ -158,9 +159,10 @@ static void netlink_sock_destruct(struct sock *sk)
                printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
                return;
        }
-       BUG_TRAP(!atomic_read(&sk->sk_rmem_alloc));
-       BUG_TRAP(!atomic_read(&sk->sk_wmem_alloc));
-       BUG_TRAP(!nlk_sk(sk)->groups);
+
+       WARN_ON(atomic_read(&sk->sk_rmem_alloc));
+       WARN_ON(atomic_read(&sk->sk_wmem_alloc));
+       WARN_ON(nlk_sk(sk)->groups);
 }
 
 /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
@@ -434,7 +436,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol)
                return -EPROTONOSUPPORT;
 
        netlink_lock_table();
-#ifdef CONFIG_KMOD
+#ifdef CONFIG_MODULES
        if (!nl_table[protocol].registered) {
                netlink_unlock_table();
                request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
@@ -451,6 +453,10 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol)
        if (err < 0)
                goto out_module;
 
+       local_bh_disable();
+       sock_prot_inuse_add(net, &netlink_proto, 1);
+       local_bh_enable();
+
        nlk = nlk_sk(sock->sk);
        nlk->module = module;
 out:
@@ -510,6 +516,9 @@ static int netlink_release(struct socket *sock)
        kfree(nlk->groups);
        nlk->groups = NULL;
 
+       local_bh_disable();
+       sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
+       local_bh_enable();
        sock_put(sk);
        return 0;
 }
@@ -942,6 +951,7 @@ struct netlink_broadcast_data {
        u32 pid;
        u32 group;
        int failure;
+       int delivery_failure;
        int congested;
        int delivered;
        gfp_t allocation;
@@ -986,11 +996,15 @@ 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;
@@ -1017,6 +1031,7 @@ 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;
@@ -1037,13 +1052,14 @@ int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
        if (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);
@@ -1151,6 +1167,13 @@ 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;
        default:
                err = -ENOPROTOOPT;
        }
@@ -1183,6 +1206,16 @@ 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;
        default:
                err = -ENOPROTOOPT;
        }
@@ -1727,12 +1760,18 @@ 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;
 }