root/net/packet/diag.c
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>
#include <linux/sock_diag.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/packet_diag.h>
#include <linux/percpu.h>
#include <net/net_namespace.h>
#include <net/sock.h>

#include "internal.h"

static int pdiag_put_info(const struct packet_sock *po, struct sk_buff *nlskb)
{
        struct packet_diag_info pinfo;

        pinfo.pdi_index = po->ifindex;
        pinfo.pdi_version = po->tp_version;
        pinfo.pdi_reserve = po->tp_reserve;
        pinfo.pdi_copy_thresh = READ_ONCE(po->copy_thresh);
        pinfo.pdi_tstamp = READ_ONCE(po->tp_tstamp);

        pinfo.pdi_flags = 0;
        if (packet_sock_flag(po, PACKET_SOCK_RUNNING))
                pinfo.pdi_flags |= PDI_RUNNING;
        if (packet_sock_flag(po, PACKET_SOCK_AUXDATA))
                pinfo.pdi_flags |= PDI_AUXDATA;
        if (packet_sock_flag(po, PACKET_SOCK_ORIGDEV))
                pinfo.pdi_flags |= PDI_ORIGDEV;
        if (READ_ONCE(po->vnet_hdr_sz))
                pinfo.pdi_flags |= PDI_VNETHDR;
        if (packet_sock_flag(po, PACKET_SOCK_TP_LOSS))
                pinfo.pdi_flags |= PDI_LOSS;

        return nla_put(nlskb, PACKET_DIAG_INFO, sizeof(pinfo), &pinfo);
}

static int pdiag_put_mclist(const struct packet_sock *po, struct sk_buff *nlskb)
{
        struct nlattr *mca;
        struct packet_mclist *ml;

        mca = nla_nest_start_noflag(nlskb, PACKET_DIAG_MCLIST);
        if (!mca)
                return -EMSGSIZE;

        rtnl_lock();
        for (ml = po->mclist; ml; ml = ml->next) {
                struct packet_diag_mclist *dml;

                dml = nla_reserve_nohdr(nlskb, sizeof(*dml));
                if (!dml) {
                        rtnl_unlock();
                        nla_nest_cancel(nlskb, mca);
                        return -EMSGSIZE;
                }

                dml->pdmc_index = ml->ifindex;
                dml->pdmc_type = ml->type;
                dml->pdmc_alen = ml->alen;
                dml->pdmc_count = ml->count;
                BUILD_BUG_ON(sizeof(dml->pdmc_addr) != sizeof(ml->addr));
                memcpy(dml->pdmc_addr, ml->addr, sizeof(ml->addr));
        }

        rtnl_unlock();
        nla_nest_end(nlskb, mca);

        return 0;
}

static int pdiag_put_ring(struct packet_ring_buffer *ring, int ver, int nl_type,
                struct sk_buff *nlskb)
{
        struct packet_diag_ring pdr;

        if (!ring->pg_vec)
                return 0;

        pdr.pdr_block_size = ring->pg_vec_pages << PAGE_SHIFT;
        pdr.pdr_block_nr = ring->pg_vec_len;
        pdr.pdr_frame_size = ring->frame_size;
        pdr.pdr_frame_nr = ring->frame_max + 1;

        if (ver > TPACKET_V2) {
                pdr.pdr_retire_tmo = ktime_to_ms(ring->prb_bdqc.interval_ktime);
                pdr.pdr_sizeof_priv = ring->prb_bdqc.blk_sizeof_priv;
                pdr.pdr_features = ring->prb_bdqc.feature_req_word;
        } else {
                pdr.pdr_retire_tmo = 0;
                pdr.pdr_sizeof_priv = 0;
                pdr.pdr_features = 0;
        }

        return nla_put(nlskb, nl_type, sizeof(pdr), &pdr);
}

static int pdiag_put_rings_cfg(struct packet_sock *po, struct sk_buff *skb)
{
        int ret;

        mutex_lock(&po->pg_vec_lock);
        ret = pdiag_put_ring(&po->rx_ring, po->tp_version,
                        PACKET_DIAG_RX_RING, skb);
        if (!ret)
                ret = pdiag_put_ring(&po->tx_ring, po->tp_version,
                                PACKET_DIAG_TX_RING, skb);
        mutex_unlock(&po->pg_vec_lock);

        return ret;
}

static int pdiag_put_fanout(struct packet_sock *po, struct sk_buff *nlskb)
{
        int ret = 0;

        mutex_lock(&fanout_mutex);
        if (po->fanout) {
                u32 val;

                val = (u32)po->fanout->id | ((u32)po->fanout->type << 16);
                ret = nla_put_u32(nlskb, PACKET_DIAG_FANOUT, val);
        }
        mutex_unlock(&fanout_mutex);

        return ret;
}

static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
                        struct packet_diag_req *req,
                        bool may_report_filterinfo,
                        struct user_namespace *user_ns,
                        u32 portid, u32 seq, u32 flags, int sk_ino)
{
        struct nlmsghdr *nlh;
        struct packet_diag_msg *rp;
        struct packet_sock *po = pkt_sk(sk);

        nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rp), flags);
        if (!nlh)
                return -EMSGSIZE;

        rp = nlmsg_data(nlh);
        rp->pdiag_family = AF_PACKET;
        rp->pdiag_type = sk->sk_type;
        rp->pdiag_num = ntohs(READ_ONCE(po->num));
        rp->pdiag_ino = sk_ino;
        sock_diag_save_cookie(sk, rp->pdiag_cookie);

        if ((req->pdiag_show & PACKET_SHOW_INFO) &&
                        pdiag_put_info(po, skb))
                goto out_nlmsg_trim;

        if ((req->pdiag_show & PACKET_SHOW_INFO) &&
            nla_put_u32(skb, PACKET_DIAG_UID,
                        from_kuid_munged(user_ns, sk_uid(sk))))
                goto out_nlmsg_trim;

        if ((req->pdiag_show & PACKET_SHOW_MCLIST) &&
                        pdiag_put_mclist(po, skb))
                goto out_nlmsg_trim;

        if ((req->pdiag_show & PACKET_SHOW_RING_CFG) &&
                        pdiag_put_rings_cfg(po, skb))
                goto out_nlmsg_trim;

        if ((req->pdiag_show & PACKET_SHOW_FANOUT) &&
                        pdiag_put_fanout(po, skb))
                goto out_nlmsg_trim;

        if ((req->pdiag_show & PACKET_SHOW_MEMINFO) &&
            sock_diag_put_meminfo(sk, skb, PACKET_DIAG_MEMINFO))
                goto out_nlmsg_trim;

        if ((req->pdiag_show & PACKET_SHOW_FILTER) &&
            sock_diag_put_filterinfo(may_report_filterinfo, sk, skb,
                                     PACKET_DIAG_FILTER))
                goto out_nlmsg_trim;

        nlmsg_end(skb, nlh);
        return 0;

out_nlmsg_trim:
        nlmsg_cancel(skb, nlh);
        return -EMSGSIZE;
}

static int packet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
        int num = 0, s_num = cb->args[0];
        struct packet_diag_req *req;
        struct net *net;
        struct sock *sk;
        bool may_report_filterinfo;

        net = sock_net(skb->sk);
        req = nlmsg_data(cb->nlh);
        may_report_filterinfo = netlink_net_capable(cb->skb, CAP_NET_ADMIN);

        mutex_lock(&net->packet.sklist_lock);
        sk_for_each(sk, &net->packet.sklist) {
                if (!net_eq(sock_net(sk), net))
                        continue;
                if (num < s_num)
                        goto next;

                if (sk_diag_fill(sk, skb, req,
                                 may_report_filterinfo,
                                 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)
                        goto done;
next:
                num++;
        }
done:
        mutex_unlock(&net->packet.sklist_lock);
        cb->args[0] = num;

        return skb->len;
}

static int packet_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
{
        int hdrlen = sizeof(struct packet_diag_req);
        struct net *net = sock_net(skb->sk);
        struct packet_diag_req *req;

        if (nlmsg_len(h) < hdrlen)
                return -EINVAL;

        req = nlmsg_data(h);
        /* Make it possible to support protocol filtering later */
        if (req->sdiag_protocol)
                return -EINVAL;

        if (h->nlmsg_flags & NLM_F_DUMP) {
                struct netlink_dump_control c = {
                        .dump = packet_diag_dump,
                };
                return netlink_dump_start(net->diag_nlsk, skb, h, &c);
        } else
                return -EOPNOTSUPP;
}

static const struct sock_diag_handler packet_diag_handler = {
        .owner = THIS_MODULE,
        .family = AF_PACKET,
        .dump = packet_diag_handler_dump,
};

static int __init packet_diag_init(void)
{
        return sock_diag_register(&packet_diag_handler);
}

static void __exit packet_diag_exit(void)
{
        sock_diag_unregister(&packet_diag_handler);
}

module_init(packet_diag_init);
module_exit(packet_diag_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("PACKET socket monitoring via SOCK_DIAG");
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 17 /* AF_PACKET */);