netdev - Re: [PATCH] Netlink messages for multicast HW addr programming

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1453477775.20378.15.camel@brocade.com>
Date:	Fri, 22 Jan 2016 15:49:36 +0000
From:	Patrick Ruddy <pruddy@...cade.com>
To:	"jiri@...nulli.us" <jiri@...nulli.us>
CC:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	David Stapleton <dstaplet@...cade.com>,
	Olufemi Komolafe <okomolaf@...cade.com>,
	"Stephen Hemminger" <shemming@...cade.com>
Subject: Re: [PATCH] Netlink messages for multicast HW addr programming

On Fri, 2016-01-22 at 16:05 +0100, Jiri Pirko wrote:
> Fri, Jan 22, 2016 at 03:51:55PM CET, pruddy@...cade.com wrote:
> >On Thu, 2016-01-21 at 21:04 +0100, Jiri Pirko wrote:
> >> Thu, Jan 21, 2016 at 12:47:54PM CET, pruddy@...cade.com wrote:
> >> >Add RTM_NEWADDR and RTM_DELADDR netlink messages to indicate
> >> >interest in specific multicast hardware addresses. These messages
> >> >are sent when addressed are added or deleted from the appropriate
> >> >interface driver.
> >> >
> >> >Signed-off-by: Patrick Ruddy <pruddy@...cade.com>
> >> >
> >> >diff --git a/net/core/dev_addr_lists.c b/net/core/dev_addr_lists.c
> >> >index c0548d2..a0ebadd 100644
> >> >--- a/net/core/dev_addr_lists.c
> >> >+++ b/net/core/dev_addr_lists.c
> >> >@@ -12,6 +12,7 @@
> >> >  */
> >> > 
> >> > #include <linux/netdevice.h>
> >> >+#include <net/netlink.h>
> >> > #include <linux/rtnetlink.h>
> >> > #include <linux/export.h>
> >> > #include <linux/list.h>
> >> >@@ -661,6 +662,62 @@ out:
> >> > }
> >> > EXPORT_SYMBOL(dev_mc_add_excl);
> >> > 
> >> >+static int fill_addr(struct sk_buff *skb, struct net_device *dev,
> >> >+		     const unsigned char *addr, int type)
> >> >+{
> >> >+	struct nlmsghdr *nlh;
> >> >+	struct ifaddrmsg *ifm;
> >> >+
> >> >+	nlh = nlmsg_put(skb, 0, 0, type, sizeof(*ifm), 0);
> >> >+	if (nlh == NULL)
> >> >+		return -EMSGSIZE;
> >> >+
> >> >+	ifm = nlmsg_data(nlh);
> >> >+	ifm->ifa_family = AF_UNSPEC;
> >> >+	ifm->ifa_prefixlen = 0;
> >> >+	ifm->ifa_flags = IFA_F_PERMANENT;
> >> >+	ifm->ifa_scope = RT_SCOPE_LINK;
> >> >+	ifm->ifa_index = dev->ifindex;
> >> >+	if (nla_put(skb, IFA_ADDRESS, dev->addr_len, addr))
> >> >+		goto nla_put_failure;
> >> >+	nlmsg_end(skb, nlh);
> >> 
> >> How can userspace tell if this is a multicast addr? Also, why not add
> >> notifications for unicast addrs so we handle both the same?
> >
> >I am only using this RTM_NEW/DELADDR AF_UNSPEC message for multicast
> >addresses. I understand that the unicast addresses are notified in the
> >RTM_NEW/DELLINK.
> 
> dev->dev_addr is notified by that. UC addresses do not have any
> notification now.
It is the multicast MAC address (ie the multicast equivalent of the
dev_addr) that we are notifying here right? Not L3 addresses.

-pr