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authorPablo Neira Ayuso <pablo@netfilter.org>2009-02-18 01:40:43 +0000
committerDavid S. Miller <davem@davemloft.net>2009-02-20 01:01:08 -0800
commitbe0c22a46cfb79ab2342bb28fde99afa94ef868e (patch)
treeda112ef3066d75a7e5adcfe3355ad2b60ef1929b /net/netlink
parent2d96cf8cdfd625da51e5d237d564cd75d3147547 (diff)
netlink: add NETLINK_BROADCAST_ERROR socket option
This patch adds NETLINK_BROADCAST_ERROR which is a netlink socket option that the listener can set to make netlink_broadcast() return errors in the delivery to the caller. This option is useful if the caller of netlink_broadcast() do something with the result of the message delivery, like in ctnetlink where it drops a network packet if the event delivery failed, this is used to enable reliable logging and state-synchronization. If this socket option is not set, netlink_broadcast() only reports ESRCH errors and silently ignore ENOBUFS errors, which is what most netlink_broadcast() callers should do. This socket option is based on a suggestion from Patrick McHardy. Patrick McHardy can exchange this patch for a beer from me ;). Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Acked-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink')
-rw-r--r--net/netlink/af_netlink.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 6ee69c27f80..ed587be1e1c 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -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)
{
@@ -995,12 +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);
- p->delivery_failure = 1;
+ if (nlk->flags & NETLINK_BROADCAST_SEND_ERROR)
+ p->delivery_failure = 1;
} else {
p->congested |= val;
p->delivered = 1;
@@ -1048,7 +1052,7 @@ int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 pid,
if (info.skb2)
kfree_skb(info.skb2);
- if (info.delivery_failure || info.failure)
+ if (info.delivery_failure)
return -ENOBUFS;
if (info.delivered) {
@@ -1163,6 +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;
}
@@ -1195,6 +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;
}