// SPDX-License-Identifier: GPL-2.0
  /* XDP sockets monitoring support
   *
   * Copyright(c) 2019 Intel Corporation.
   *
   * Author: Björn Töpel <bjorn.topel@intel.com>
   */
  
  #include <linux/module.h>
  #include <net/xdp_sock.h>
  #include <linux/xdp_diag.h>
  #include <linux/sock_diag.h>
  
  #include "xsk_queue.h"
  #include "xsk.h"
  
  static int xsk_diag_put_info(const struct xdp_sock *xs, struct sk_buff *nlskb)
  {
  	struct xdp_diag_info di = {};
  
  	di.ifindex = xs->dev ? xs->dev->ifindex : 0;
  	di.queue_id = xs->queue_id;
  	return nla_put(nlskb, XDP_DIAG_INFO, sizeof(di), &di);
  }
  
  static int xsk_diag_put_ring(const struct xsk_queue *queue, int nl_type,
  			     struct sk_buff *nlskb)
  {
  	struct xdp_diag_ring dr = {};
  
  	dr.entries = queue->nentries;
  	return nla_put(nlskb, nl_type, sizeof(dr), &dr);
  }
  
  static int xsk_diag_put_rings_cfg(const struct xdp_sock *xs,
  				  struct sk_buff *nlskb)
  {
  	int err = 0;
  
  	if (xs->rx)
  		err = xsk_diag_put_ring(xs->rx, XDP_DIAG_RX_RING, nlskb);
  	if (!err && xs->tx)
  		err = xsk_diag_put_ring(xs->tx, XDP_DIAG_TX_RING, nlskb);
  	return err;
  }
  
  static int xsk_diag_put_umem(const struct xdp_sock *xs, struct sk_buff *nlskb)
  {

  	struct xsk_buff_pool *pool = xs->pool;

  	struct xdp_umem *umem = xs->umem;
  	struct xdp_diag_umem du = {};
  	int err;
  
  	if (!umem)
  		return 0;
  
  	du.id = umem->id;
  	du.size = umem->size;
  	du.num_pages = umem->npgs;

  	du.chunk_size = umem->chunk_size;

  	du.headroom = umem->headroom;

  	du.ifindex = (pool && pool->netdev) ? pool->netdev->ifindex : 0;
  	du.queue_id = pool ? pool->queue_id : 0;

  	du.flags = 0;
  	if (umem->zc)
  		du.flags |= XDP_DU_F_ZEROCOPY;
  	du.refs = refcount_read(&umem->users);
  
  	err = nla_put(nlskb, XDP_DIAG_UMEM, sizeof(du), &du);

  	if (!err && pool && pool->fq)

  		err = xsk_diag_put_ring(pool->fq,
  					XDP_DIAG_UMEM_FILL_RING, nlskb);

  	if (!err && pool && pool->cq)
  		err = xsk_diag_put_ring(pool->cq,
  					XDP_DIAG_UMEM_COMPLETION_RING, nlskb);

  	return err;
  }

  static int xsk_diag_put_stats(const struct xdp_sock *xs, struct sk_buff *nlskb)
  {
  	struct xdp_diag_stats du = {};
  
  	du.n_rx_dropped = xs->rx_dropped;
  	du.n_rx_invalid = xskq_nb_invalid_descs(xs->rx);
  	du.n_rx_full = xs->rx_queue_full;

  	du.n_fill_ring_empty = xs->pool ? xskq_nb_queue_empty_descs(xs->pool->fq) : 0;

  	du.n_tx_invalid = xskq_nb_invalid_descs(xs->tx);
  	du.n_tx_ring_empty = xskq_nb_queue_empty_descs(xs->tx);
  	return nla_put(nlskb, XDP_DIAG_STATS, sizeof(du), &du);
  }

  static int xsk_diag_fill(struct sock *sk, struct sk_buff *nlskb,
  			 struct xdp_diag_req *req,
  			 struct user_namespace *user_ns,
  			 u32 portid, u32 seq, u32 flags, int sk_ino)
  {
  	struct xdp_sock *xs = xdp_sk(sk);
  	struct xdp_diag_msg *msg;
  	struct nlmsghdr *nlh;
  
  	nlh = nlmsg_put(nlskb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*msg),
  			flags);
  	if (!nlh)
  		return -EMSGSIZE;
  
  	msg = nlmsg_data(nlh);
  	memset(msg, 0, sizeof(*msg));
  	msg->xdiag_family = AF_XDP;
  	msg->xdiag_type = sk->sk_type;
  	msg->xdiag_ino = sk_ino;
  	sock_diag_save_cookie(sk, msg->xdiag_cookie);

  	mutex_lock(&xs->mutex);

  	if ((req->xdiag_show & XDP_SHOW_INFO) && xsk_diag_put_info(xs, nlskb))
  		goto out_nlmsg_trim;
  
  	if ((req->xdiag_show & XDP_SHOW_INFO) &&
  	    nla_put_u32(nlskb, XDP_DIAG_UID,
  			from_kuid_munged(user_ns, sock_i_uid(sk))))
  		goto out_nlmsg_trim;
  
  	if ((req->xdiag_show & XDP_SHOW_RING_CFG) &&
  	    xsk_diag_put_rings_cfg(xs, nlskb))
  		goto out_nlmsg_trim;
  
  	if ((req->xdiag_show & XDP_SHOW_UMEM) &&
  	    xsk_diag_put_umem(xs, nlskb))
  		goto out_nlmsg_trim;
  
  	if ((req->xdiag_show & XDP_SHOW_MEMINFO) &&
  	    sock_diag_put_meminfo(sk, nlskb, XDP_DIAG_MEMINFO))
  		goto out_nlmsg_trim;

  	if ((req->xdiag_show & XDP_SHOW_STATS) &&
  	    xsk_diag_put_stats(xs, nlskb))
  		goto out_nlmsg_trim;

  	mutex_unlock(&xs->mutex);

  	nlmsg_end(nlskb, nlh);
  	return 0;
  
  out_nlmsg_trim:

  	mutex_unlock(&xs->mutex);

  	nlmsg_cancel(nlskb, nlh);
  	return -EMSGSIZE;
  }
  
  static int xsk_diag_dump(struct sk_buff *nlskb, struct netlink_callback *cb)
  {
  	struct xdp_diag_req *req = nlmsg_data(cb->nlh);
  	struct net *net = sock_net(nlskb->sk);
  	int num = 0, s_num = cb->args[0];
  	struct sock *sk;
  
  	mutex_lock(&net->xdp.lock);
  
  	sk_for_each(sk, &net->xdp.list) {
  		if (!net_eq(sock_net(sk), net))
  			continue;
  		if (num++ < s_num)
  			continue;
  
  		if (xsk_diag_fill(sk, nlskb, req,
  				  sk_user_ns(NETLINK_CB(cb->skb).sk),
  				  NETLINK_CB(cb->skb).portid,
  				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
  				  sock_i_ino(sk)) < 0) {
  			num--;
  			break;
  		}
  	}
  
  	mutex_unlock(&net->xdp.lock);
  	cb->args[0] = num;
  	return nlskb->len;
  }
  
  static int xsk_diag_handler_dump(struct sk_buff *nlskb, struct nlmsghdr *hdr)
  {
  	struct netlink_dump_control c = { .dump = xsk_diag_dump };
  	int hdrlen = sizeof(struct xdp_diag_req);
  	struct net *net = sock_net(nlskb->sk);
  
  	if (nlmsg_len(hdr) < hdrlen)
  		return -EINVAL;
  
  	if (!(hdr->nlmsg_flags & NLM_F_DUMP))
  		return -EOPNOTSUPP;
  
  	return netlink_dump_start(net->diag_nlsk, nlskb, hdr, &c);
  }
  
  static const struct sock_diag_handler xsk_diag_handler = {
  	.family = AF_XDP,
  	.dump = xsk_diag_handler_dump,
  };
  
  static int __init xsk_diag_init(void)
  {
  	return sock_diag_register(&xsk_diag_handler);
  }
  
  static void __exit xsk_diag_exit(void)
  {
  	sock_diag_unregister(&xsk_diag_handler);
  }
  
  module_init(xsk_diag_init);
  module_exit(xsk_diag_exit);
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, AF_XDP);