diag.c

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#include <linux/module.h>
#include <linux/sock_diag.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/packet_diag.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 = po->copy_thresh;
    pinfo.pdi_tstamp = po->tp_tstamp;

    pinfo.pdi_flags = 0;
    if (po->running)
        pinfo.pdi_flags |= PDI_RUNNING;
    if (po->auxdata)
        pinfo.pdi_flags |= PDI_AUXDATA;
    if (po->origdev)
        pinfo.pdi_flags |= PDI_ORIGDEV;
    if (po->has_vnet_hdr)
        pinfo.pdi_flags |= PDI_VNETHDR;
    if (po->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(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 || ((ver > TPACKET_V2) &&
                (nl_type == PACKET_DIAG_TX_RING)))
        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 = ring->prb_bdqc.retire_blk_tov;
        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,
        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(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_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;

    return nlmsg_end(skb, nlh);

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;
    struct hlist_node *node;

    net = sock_net(skb->sk);
    req = nlmsg_data(cb->nlh);

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

        if (sk_diag_fill(sk, skb, req, 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 = {
    .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_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 17 /* AF_PACKET */);