udp_diag.c

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/*
 * udp_diag.c   Module for monitoring UDP transport protocols sockets.
 *
 * Authors: Pavel Emelyanov, <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */


#include <linux/module.h>
#include <linux/inet_diag.h>
#include <linux/udp.h>
#include <net/udp.h>
#include <net/udplite.h>
#include <linux/sock_diag.h>

static int sk_diag_dump(struct sock *sk, struct sk_buff *skb,
        struct netlink_callback *cb, struct inet_diag_req_v2 *req,
        struct nlattr *bc)
{
    if (!inet_diag_bc_sk(bc, sk))
        return 0;

    return inet_sk_diag_fill(sk, NULL, skb, req,
            sk_user_ns(NETLINK_CB(cb->skb).ssk),
            NETLINK_CB(cb->skb).portid,
            cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh);
}

static int udp_dump_one(struct udp_table *tbl, struct sk_buff *in_skb,
        const struct nlmsghdr *nlh, struct inet_diag_req_v2 *req)
{
    int err = -EINVAL;
    struct sock *sk;
    struct sk_buff *rep;
    struct net *net = sock_net(in_skb->sk);

    if (req->sdiag_family == AF_INET)
        sk = __udp4_lib_lookup(net,
                req->id.idiag_src[0], req->id.idiag_sport,
                req->id.idiag_dst[0], req->id.idiag_dport,
                req->id.idiag_if, tbl);
#if IS_ENABLED(CONFIG_IPV6)
    else if (req->sdiag_family == AF_INET6)
        sk = __udp6_lib_lookup(net,
                (struct in6_addr *)req->id.idiag_src,
                req->id.idiag_sport,
                (struct in6_addr *)req->id.idiag_dst,
                req->id.idiag_dport,
                req->id.idiag_if, tbl);
#endif
    else
        goto out_nosk;

    err = -ENOENT;
    if (sk == NULL)
        goto out_nosk;

    err = sock_diag_check_cookie(sk, req->id.idiag_cookie);
    if (err)
        goto out;

    err = -ENOMEM;
    rep = alloc_skb(NLMSG_SPACE((sizeof(struct inet_diag_msg) +
                     sizeof(struct inet_diag_meminfo) +
                     64)), GFP_KERNEL);
    if (!rep)
        goto out;

    err = inet_sk_diag_fill(sk, NULL, rep, req,
               sk_user_ns(NETLINK_CB(in_skb).ssk),
               NETLINK_CB(in_skb).portid,
               nlh->nlmsg_seq, 0, nlh);
    if (err < 0) {
        WARN_ON(err == -EMSGSIZE);
        kfree_skb(rep);
        goto out;
    }
    err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,
                  MSG_DONTWAIT);
    if (err > 0)
        err = 0;
out:
    if (sk)
        sock_put(sk);
out_nosk:
    return err;
}

static void udp_dump(struct udp_table *table, struct sk_buff *skb, struct netlink_callback *cb,
        struct inet_diag_req_v2 *r, struct nlattr *bc)
{
    int num, s_num, slot, s_slot;
    struct net *net = sock_net(skb->sk);

    s_slot = cb->args[0];
    num = s_num = cb->args[1];

    for (slot = s_slot; slot <= table->mask; num = s_num = 0, slot++) {
        struct sock *sk;
        struct hlist_nulls_node *node;
        struct udp_hslot *hslot = &table->hash[slot];

        if (hlist_nulls_empty(&hslot->head))
            continue;

        spin_lock_bh(&hslot->lock);
        sk_nulls_for_each(sk, node, &hslot->head) {
            struct inet_sock *inet = inet_sk(sk);

            if (!net_eq(sock_net(sk), net))
                continue;
            if (num < s_num)
                goto next;
            if (!(r->idiag_states & (1 << sk->sk_state)))
                goto next;
            if (r->sdiag_family != AF_UNSPEC &&
                    sk->sk_family != r->sdiag_family)
                goto next;
            if (r->id.idiag_sport != inet->inet_sport &&
                r->id.idiag_sport)
                goto next;
            if (r->id.idiag_dport != inet->inet_dport &&
                r->id.idiag_dport)
                goto next;

            if (sk_diag_dump(sk, skb, cb, r, bc) < 0) {
                spin_unlock_bh(&hslot->lock);
                goto done;
            }
next:
            num++;
        }
        spin_unlock_bh(&hslot->lock);
    }
done:
    cb->args[0] = slot;
    cb->args[1] = num;
}

static void udp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
        struct inet_diag_req_v2 *r, struct nlattr *bc)
{
    udp_dump(&udp_table, skb, cb, r, bc);
}

static int udp_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,
        struct inet_diag_req_v2 *req)
{
    return udp_dump_one(&udp_table, in_skb, nlh, req);
}

static void udp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
        void *info)
{
    r->idiag_rqueue = sk_rmem_alloc_get(sk);
    r->idiag_wqueue = sk_wmem_alloc_get(sk);
}

static const struct inet_diag_handler udp_diag_handler = {
    .dump        = udp_diag_dump,
    .dump_one    = udp_diag_dump_one,
    .idiag_get_info  = udp_diag_get_info,
    .idiag_type  = IPPROTO_UDP,
};

static void udplite_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
        struct inet_diag_req_v2 *r, struct nlattr *bc)
{
    udp_dump(&udplite_table, skb, cb, r, bc);
}

static int udplite_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,
        struct inet_diag_req_v2 *req)
{
    return udp_dump_one(&udplite_table, in_skb, nlh, req);
}

static const struct inet_diag_handler udplite_diag_handler = {
    .dump        = udplite_diag_dump,
    .dump_one    = udplite_diag_dump_one,
    .idiag_get_info  = udp_diag_get_info,
    .idiag_type  = IPPROTO_UDPLITE,
};

static int __init udp_diag_init(void)
{
    int err;

    err = inet_diag_register(&udp_diag_handler);
    if (err)
        goto out;
    err = inet_diag_register(&udplite_diag_handler);
    if (err)
        goto out_lite;
out:
    return err;
out_lite:
    inet_diag_unregister(&udp_diag_handler);
    goto out;
}

static void __exit udp_diag_exit(void)
{
    inet_diag_unregister(&udplite_diag_handler);
    inet_diag_unregister(&udp_diag_handler);
}

module_init(udp_diag_init);
module_exit(udp_diag_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-17 /* AF_INET - IPPROTO_UDP */);
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-136 /* AF_INET - IPPROTO_UDPLITE */);