net: add fdb generic dump routine

This adds a generic dump routine drivers can call. It
should be sufficient to handle any bridging model that
uses the unicast address list. This should be most SR-IOV
enabled NICs.

v2: return error on nlmsg_put and use -EMSGSIZE instead
    of -ENOMEM this is inline other usages

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 84 insertions, 0 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index b348b7fbf53a..e8488c7b092c 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1980,6 +1980,37 @@ errout:
                 rtnl_set_sk_err(net, RTNLGRP_LINK, err);
 }
 
+static int nlmsg_populate_fdb_fill(struct sk_buff *skb,
+                                   struct net_device *dev,
+                                   u8 *addr, u32 pid, u32 seq,
+                                   int type, unsigned int flags)
+{
+        struct nlmsghdr *nlh;
+        struct ndmsg *ndm;
+
+        nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), NLM_F_MULTI);
+        if (!nlh)
+                return -EMSGSIZE;
+
+        ndm = nlmsg_data(nlh);
+        ndm->ndm_family  = AF_BRIDGE;
+        ndm->ndm_pad1    = 0;
+        ndm->ndm_pad2    = 0;
+        ndm->ndm_flags   = flags;
+        ndm->ndm_type    = 0;
+        ndm->ndm_ifindex = dev->ifindex;
+        ndm->ndm_state   = NUD_PERMANENT;
+
+        if (nla_put(skb, NDA_LLADDR, ETH_ALEN, addr))
+                goto nla_put_failure;
+
+        return nlmsg_end(skb, nlh);
+
+nla_put_failure:
+        nlmsg_cancel(skb, nlh);
+        return -EMSGSIZE;
+}
+
 static int rtnl_fdb_add(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 {
         struct net *net = sock_net(skb->sk);
@@ -2101,6 +2132,59 @@ out:
         return err;
 }
 
+static int nlmsg_populate_fdb(struct sk_buff *skb,
+                              struct netlink_callback *cb,
+                              struct net_device *dev,
+                              int *idx,
+                              struct netdev_hw_addr_list *list)
+{
+        struct netdev_hw_addr *ha;
+        int err;
+        u32 pid, seq;
+
+        pid = NETLINK_CB(cb->skb).pid;
+        seq = cb->nlh->nlmsg_seq;
+
+        list_for_each_entry(ha, &list->list, list) {
+                if (*idx < cb->args[0])
+                        goto skip;
+
+                err = nlmsg_populate_fdb_fill(skb, dev, ha->addr,
+                                              pid, seq, 0, NTF_SELF);
+                if (err < 0)
+                        return err;
+skip:
+                *idx += 1;
+        }
+        return 0;
+}
+
+/**
+ * ndo_dflt_fdb_dump: default netdevice operation to dump an FDB table.
+ * @nlh: netlink message header
+ * @dev: netdevice
+ *
+ * Default netdevice operation to dump the existing unicast address list.
+ * Returns zero on success.
+ */
+int ndo_dflt_fdb_dump(struct sk_buff *skb,
+                      struct netlink_callback *cb,
+                      struct net_device *dev,
+                      int idx)
+{
+        int err;
+
+        netif_addr_lock_bh(dev);
+        err = nlmsg_populate_fdb(skb, cb, dev, &idx, &dev->uc);
+        if (err)
+                goto out;
+        nlmsg_populate_fdb(skb, cb, dev, &idx, &dev->mc);
+out:
+        netif_addr_unlock_bh(dev);
+        return idx;
+}
+EXPORT_SYMBOL(ndo_dflt_fdb_dump);
+
 static int rtnl_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
         int idx = 0;