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

Jiri Pirko
2016-01-22T15:05:11Z

Fri, Jan 22, 2016 at 03:51:55PM CET, pruddy@Brocade.com wrote:
>On Thu, 2016-01-21 at 21:04 +0100, Jiri Pirko wrote:
>> Thu, Jan 21, 2016 at 12:47:54PM CET, pruddy@brocade.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@brocade.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.