neighbor: Add protocol attribute

Similar to routes and rules, add protocol attribute to neighbor entries
for easier tracking of how each was created.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 26 insertions, 1 deletions

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 30fd50adf234..66221f1991c0 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -149,6 +149,7 @@ struct neighbour {
         __u8                    nud_state;
         __u8                    type;
         __u8                    dead;
+        u8                      protocol;
         seqlock_t               ha_lock;
         unsigned char           ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))] __aligned(8);
         struct hh_cache         hh;
@@ -173,6 +174,7 @@ struct pneigh_entry {
         possible_net_t          net;
         struct net_device       *dev;
         u8                      flags;
+        u8                      protocol;
         u8                      key[0];
 };
 
diff --git a/include/uapi/linux/neighbour.h b/include/uapi/linux/neighbour.h
index 998155444e0d..cd144e3099a3 100644
--- a/include/uapi/linux/neighbour.h
+++ b/include/uapi/linux/neighbour.h
@@ -28,6 +28,7 @@ enum {
         NDA_MASTER,
         NDA_LINK_NETNSID,
         NDA_SRC_VNI,
+        NDA_PROTOCOL,  /* Originator of entry */
         __NDA_MAX
 };
 
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 42b413774370..fb4372cb1de1 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1828,6 +1828,7 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
         struct net_device *dev = NULL;
         struct neighbour *neigh;
         void *dst, *lladdr;
+        u8 protocol = 0;
         int err;
 
         ASSERT_RTNL();
@@ -1867,6 +1868,14 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
         dst = nla_data(tb[NDA_DST]);
         lladdr = tb[NDA_LLADDR] ? nla_data(tb[NDA_LLADDR]) : NULL;
 
+        if (tb[NDA_PROTOCOL]) {
+                if (nla_len(tb[NDA_PROTOCOL]) != sizeof(u8)) {
+                        NL_SET_ERR_MSG(extack, "Invalid protocol attribute");
+                        goto out;
+                }
+                protocol = nla_get_u8(tb[NDA_PROTOCOL]);
+        }
+
         if (ndm->ndm_flags & NTF_PROXY) {
                 struct pneigh_entry *pn;
 
@@ -1874,6 +1883,8 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
                 pn = pneigh_lookup(tbl, net, dst, dev, 1);
                 if (pn) {
                         pn->flags = ndm->ndm_flags;
+                        if (protocol)
+                                pn->protocol = protocol;
                         err = 0;
                 }
                 goto out;
@@ -1924,6 +1935,10 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
         } else
                 err = __neigh_update(neigh, lladdr, ndm->ndm_state, flags,
                                      NETLINK_CB(skb).portid, extack);
+
+        if (protocol)
+                neigh->protocol = protocol;
+
         neigh_release(neigh);
 
 out:
@@ -2417,6 +2432,9 @@ static int neigh_fill_info(struct sk_buff *skb, struct neighbour *neigh,
             nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
                 goto nla_put_failure;
 
+        if (neigh->protocol && nla_put_u8(skb, NDA_PROTOCOL, neigh->protocol))
+                goto nla_put_failure;
+
         nlmsg_end(skb, nlh);
         return 0;
 
@@ -2448,6 +2466,9 @@ static int pneigh_fill_info(struct sk_buff *skb, struct pneigh_entry *pn,
         if (nla_put(skb, NDA_DST, tbl->key_len, pn->key))
                 goto nla_put_failure;
 
+        if (pn->protocol && nla_put_u8(skb, NDA_PROTOCOL, pn->protocol))
+                goto nla_put_failure;
+
         nlmsg_end(skb, nlh);
         return 0;
 
@@ -3103,7 +3124,8 @@ static inline size_t neigh_nlmsg_size(void)
                + nla_total_size(MAX_ADDR_LEN) /* NDA_DST */
                + nla_total_size(MAX_ADDR_LEN) /* NDA_LLADDR */
                + nla_total_size(sizeof(struct nda_cacheinfo))
-               + nla_total_size(4); /* NDA_PROBES */
+               + nla_total_size(4)  /* NDA_PROBES */
+               + nla_total_size(1); /* NDA_PROTOCOL */
 }
 
 static void __neigh_notify(struct neighbour *n, int type, int flags,