From 1ce85fe402137824246bad03ff85f3913d565c17 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 24 Feb 2009 23:18:28 -0800 Subject: netlink: change nlmsg_notify() return value logic This patch changes the return value of nlmsg_notify() as follows: If NETLINK_BROADCAST_ERROR is set by any of the listeners and an error in the delivery happened, return the broadcast error; else if there are no listeners apart from the socket that requested a change with the echo flag, return the result of the unicast notification. Thus, with this patch, the unicast notification is handled in the same way of a broadcast listener that has set the NETLINK_BROADCAST_ERROR socket flag. This patch is useful in case that the caller of nlmsg_notify() wants to know the result of the delivery of a netlink notification (including the broadcast delivery) and take any action in case that the delivery failed. For example, ctnetlink can drop packets if the event delivery failed to provide reliable logging and state-synchronization at the cost of dropping packets. This patch also modifies the rtnetlink code to ignore the return value of rtnl_notify() in all callers. The function rtnl_notify() (before this patch) returned the error of the unicast notification which makes rtnl_set_sk_err() reports errors to all listeners. This is not of any help since the origin of the change (the socket that requested the echoing) notices the ENOBUFS error if the notification fails and should resync itself. Signed-off-by: Pablo Neira Ayuso Acked-by: Patrick McHardy Signed-off-by: David S. Miller --- net/core/fib_rules.c | 3 ++- net/core/neighbour.c | 3 ++- net/core/rtnetlink.c | 9 +++++---- 3 files changed, 9 insertions(+), 6 deletions(-) (limited to 'net/core') diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c index 32b3a0152d7a..98691e1466b8 100644 --- a/net/core/fib_rules.c +++ b/net/core/fib_rules.c @@ -588,7 +588,8 @@ static void notify_rule_change(int event, struct fib_rule *rule, goto errout; } - err = rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL); + rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL); + return; errout: if (err < 0) rtnl_set_sk_err(net, ops->nlgroup, err); diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 278a142d1047..e1144cb94b99 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -2534,7 +2534,8 @@ static void __neigh_notify(struct neighbour *n, int type, int flags) kfree_skb(skb); goto errout; } - err = rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC); + rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC); + return; errout: if (err < 0) rtnl_set_sk_err(net, RTNLGRP_NEIGH, err); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 790dd205bb5d..d78030f88bd0 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -455,8 +455,8 @@ int rtnl_unicast(struct sk_buff *skb, struct net *net, u32 pid) return nlmsg_unicast(rtnl, skb, pid); } -int rtnl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group, - struct nlmsghdr *nlh, gfp_t flags) +void rtnl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group, + struct nlmsghdr *nlh, gfp_t flags) { struct sock *rtnl = net->rtnl; int report = 0; @@ -464,7 +464,7 @@ int rtnl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group, if (nlh) report = nlmsg_report(nlh); - return nlmsg_notify(rtnl, skb, pid, group, report, flags); + nlmsg_notify(rtnl, skb, pid, group, report, flags); } void rtnl_set_sk_err(struct net *net, u32 group, int error) @@ -1246,7 +1246,8 @@ void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change) kfree_skb(skb); goto errout; } - err = rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_KERNEL); + rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_KERNEL); + return; errout: if (err < 0) rtnl_set_sk_err(net, RTNLGRP_LINK, err); -- cgit v1.2.3