root/net/xdp/xsk_diag.c
// 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 (READ_ONCE(xs->state) == XSK_UNBOUND)
                goto out_nlmsg_trim;

        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, sk_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 = {
        .owner = THIS_MODULE,
        .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_DESCRIPTION("XDP socket monitoring via SOCK_DIAG");
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, AF_XDP);