nexthop: Add netlink handlers for bucket get

Allow getting (but not setting) individual buckets to inspect the next hop
mapped therein, idle time, and flags.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index ed27457..3d602ef 100644 (file)
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -66,6 +66,15 @@ static const struct nla_policy rtm_nh_res_bucket_policy_dump[] = {
        [NHA_RES_BUCKET_NH_ID]  = { .type = NLA_U32 },
 };
 
+static const struct nla_policy rtm_nh_policy_get_bucket[] = {
+       [NHA_ID]                = { .type = NLA_U32 },
+       [NHA_RES_BUCKET]        = { .type = NLA_NESTED },
+};
+
+static const struct nla_policy rtm_nh_res_bucket_policy_get[] = {
+       [NHA_RES_BUCKET_INDEX]  = { .type = NLA_U16 },
+};
+
 static bool nexthop_notifiers_is_empty(struct net *net)
 {
        return !net->nexthop.notifier_chain.head;
@@ -3381,6 +3390,105 @@ out_err:
        return err;
 }
 
+static int nh_valid_get_bucket_req_res_bucket(struct nlattr *res,
+                                             u16 *bucket_index,
+                                             struct netlink_ext_ack *extack)
+{
+       struct nlattr *tb[ARRAY_SIZE(rtm_nh_res_bucket_policy_get)];
+       int err;
+
+       err = nla_parse_nested(tb, ARRAY_SIZE(rtm_nh_res_bucket_policy_get) - 1,
+                              res, rtm_nh_res_bucket_policy_get, extack);
+       if (err < 0)
+               return err;
+
+       if (!tb[NHA_RES_BUCKET_INDEX]) {
+               NL_SET_ERR_MSG(extack, "Bucket index is missing");
+               return -EINVAL;
+       }
+
+       *bucket_index = nla_get_u16(tb[NHA_RES_BUCKET_INDEX]);
+       return 0;
+}
+
+static int nh_valid_get_bucket_req(const struct nlmsghdr *nlh,
+                                  u32 *id, u16 *bucket_index,
+                                  struct netlink_ext_ack *extack)
+{
+       struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_get_bucket)];
+       int err;
+
+       err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
+                         ARRAY_SIZE(rtm_nh_policy_get_bucket) - 1,
+                         rtm_nh_policy_get_bucket, extack);
+       if (err < 0)
+               return err;
+
+       err = __nh_valid_get_del_req(nlh, tb, id, extack);
+       if (err)
+               return err;
+
+       if (!tb[NHA_RES_BUCKET]) {
+               NL_SET_ERR_MSG(extack, "Bucket information is missing");
+               return -EINVAL;
+       }
+
+       err = nh_valid_get_bucket_req_res_bucket(tb[NHA_RES_BUCKET],
+                                                bucket_index, extack);
+       if (err)
+               return err;
+
+       return 0;
+}
+
+/* rtnl */
+static int rtm_get_nexthop_bucket(struct sk_buff *in_skb, struct nlmsghdr *nlh,
+                                 struct netlink_ext_ack *extack)
+{
+       struct net *net = sock_net(in_skb->sk);
+       struct nh_res_table *res_table;
+       struct sk_buff *skb = NULL;
+       struct nh_group *nhg;
+       struct nexthop *nh;
+       u16 bucket_index;
+       int err;
+       u32 id;
+
+       err = nh_valid_get_bucket_req(nlh, &id, &bucket_index, extack);
+       if (err)
+               return err;
+
+       nh = nexthop_find_group_resilient(net, id, extack);
+       if (IS_ERR(nh))
+               return PTR_ERR(nh);
+
+       nhg = rtnl_dereference(nh->nh_grp);
+       res_table = rtnl_dereference(nhg->res_table);
+       if (bucket_index >= res_table->num_nh_buckets) {
+               NL_SET_ERR_MSG(extack, "Bucket index out of bounds");
+               return -ENOENT;
+       }
+
+       skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
+       if (!skb)
+               return -ENOBUFS;
+
+       err = nh_fill_res_bucket(skb, nh, &res_table->nh_buckets[bucket_index],
+                                bucket_index, RTM_NEWNEXTHOPBUCKET,
+                                NETLINK_CB(in_skb).portid, nlh->nlmsg_seq,
+                                0, extack);
+       if (err < 0) {
+               WARN_ON(err == -EMSGSIZE);
+               goto errout_free;
+       }
+
+       return rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
+
+errout_free:
+       kfree_skb(skb);
+       return err;
+}
+
 static void nexthop_sync_mtu(struct net_device *dev, u32 orig_mtu)
 {
        unsigned int hash = nh_dev_hashfn(dev->ifindex);
@@ -3604,7 +3712,7 @@ static int __init nexthop_init(void)
        rtnl_register(PF_INET6, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
        rtnl_register(PF_INET6, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
 
-       rtnl_register(PF_UNSPEC, RTM_GETNEXTHOPBUCKET, NULL,
+       rtnl_register(PF_UNSPEC, RTM_GETNEXTHOPBUCKET, rtm_get_nexthop_bucket,
                      rtm_dump_nexthop_bucket, 0);
 
        return 0;