From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH] netlink: add NETLINK_BROADCAST_REPORT_ERROR socket option Date: Mon, 16 Feb 2009 11:52:00 +0100 Message-ID: <20090216105200.29072.99944.stgit@Decadence> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: kaber@trash.net, davem@davemloft.net To: netdev@vger.kernel.org Return-path: Received: from mail.us.es ([193.147.175.20]:60093 "EHLO us.es" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750727AbZBPKwI (ORCPT ); Mon, 16 Feb 2009 05:52:08 -0500 Sender: netdev-owner@vger.kernel.org List-ID: This patch adds NETLINK_BROADCAST_REPORT_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. Signed-off-by: Pablo Neira Ayuso --- include/linux/netlink.h | 1 + net/netlink/af_netlink.c | 24 ++++++++++++++++++++++-- 2 files changed, 23 insertions(+), 2 deletions(-) diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 51b09a1..8978ae9 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -103,6 +103,7 @@ struct nlmsgerr #define NETLINK_ADD_MEMBERSHIP 1 #define NETLINK_DROP_MEMBERSHIP 2 #define NETLINK_PKTINFO 3 +#define NETLINK_BROADCAST_REPORT_ERROR 4 struct nl_pktinfo { diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 6ee69c2..29dd4fb 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_REPORT_ERROR 0x4 static inline struct netlink_sock *nlk_sk(struct sock *sk) { @@ -994,13 +995,15 @@ static inline int do_one_broadcast(struct sock *sk, if (p->skb2 == NULL) { netlink_overrun(sk); /* Clone failed. Notify ALL listeners. */ - p->failure = 1; + if (nlk->flags & NETLINK_BROADCAST_SEND_REPORT_ERROR) + p->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_REPORT_ERROR) + p->delivery_failure = 1; } else { p->congested |= val; p->delivered = 1; @@ -1163,6 +1166,13 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname, err = 0; break; } + case NETLINK_BROADCAST_REPORT_ERROR: + if (val) + nlk->flags |= NETLINK_BROADCAST_SEND_REPORT_ERROR; + else + nlk->flags &= ~NETLINK_BROADCAST_SEND_REPORT_ERROR; + err = 0; + break; default: err = -ENOPROTOOPT; } @@ -1195,6 +1205,16 @@ static int netlink_getsockopt(struct socket *sock, int level, int optname, return -EFAULT; err = 0; break; + case NETLINK_BROADCAST_REPORT_ERROR: + if (len < sizeof(int)) + return -EINVAL; + len = sizeof(int); + val = nlk->flags & NETLINK_BROADCAST_SEND_REPORT_ERROR ? 1 : 0; + if (put_user(len, optlen) || + put_user(val, optval)) + return -EFAULT; + err = 0; + break; default: err = -ENOPROTOOPT; }