pn_netlink.c

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/*
 * File: pn_netlink.c
 *
 * Phonet netlink interface
 *
 * Copyright (C) 2008 Nokia Corporation.
 *
 * Authors: Sakari Ailus <[email protected]>
 *          Remi Denis-Courmont
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/kernel.h>
#include <linux/netlink.h>
#include <linux/phonet.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/phonet/pn_dev.h>

/* Device address handling */

static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
             u32 portid, u32 seq, int event);

void phonet_address_notify(int event, struct net_device *dev, u8 addr)
{
    struct sk_buff *skb;
    int err = -ENOBUFS;

    skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
            nla_total_size(1), GFP_KERNEL);
    if (skb == NULL)
        goto errout;
    err = fill_addr(skb, dev, addr, 0, 0, event);
    if (err < 0) {
        WARN_ON(err == -EMSGSIZE);
        kfree_skb(skb);
        goto errout;
    }
    rtnl_notify(skb, dev_net(dev), 0,
            RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);
    return;
errout:
    rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_IFADDR, err);
}

static const struct nla_policy ifa_phonet_policy[IFA_MAX+1] = {
    [IFA_LOCAL] = { .type = NLA_U8 },
};

static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh, void *attr)
{
    struct net *net = sock_net(skb->sk);
    struct nlattr *tb[IFA_MAX+1];
    struct net_device *dev;
    struct ifaddrmsg *ifm;
    int err;
    u8 pnaddr;

    if (!capable(CAP_SYS_ADMIN))
        return -EPERM;

    ASSERT_RTNL();

    err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_phonet_policy);
    if (err < 0)
        return err;

    ifm = nlmsg_data(nlh);
    if (tb[IFA_LOCAL] == NULL)
        return -EINVAL;
    pnaddr = nla_get_u8(tb[IFA_LOCAL]);
    if (pnaddr & 3)
        /* Phonet addresses only have 6 high-order bits */
        return -EINVAL;

    dev = __dev_get_by_index(net, ifm->ifa_index);
    if (dev == NULL)
        return -ENODEV;

    if (nlh->nlmsg_type == RTM_NEWADDR)
        err = phonet_address_add(dev, pnaddr);
    else
        err = phonet_address_del(dev, pnaddr);
    if (!err)
        phonet_address_notify(nlh->nlmsg_type, dev, pnaddr);
    return err;
}

static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
            u32 portid, u32 seq, int event)
{
    struct ifaddrmsg *ifm;
    struct nlmsghdr *nlh;

    nlh = nlmsg_put(skb, portid, seq, event, sizeof(*ifm), 0);
    if (nlh == NULL)
        return -EMSGSIZE;

    ifm = nlmsg_data(nlh);
    ifm->ifa_family = AF_PHONET;
    ifm->ifa_prefixlen = 0;
    ifm->ifa_flags = IFA_F_PERMANENT;
    ifm->ifa_scope = RT_SCOPE_LINK;
    ifm->ifa_index = dev->ifindex;
    if (nla_put_u8(skb, IFA_LOCAL, addr))
        goto nla_put_failure;
    return nlmsg_end(skb, nlh);

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

static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
{
    struct phonet_device_list *pndevs;
    struct phonet_device *pnd;
    int dev_idx = 0, dev_start_idx = cb->args[0];
    int addr_idx = 0, addr_start_idx = cb->args[1];

    pndevs = phonet_device_list(sock_net(skb->sk));
    rcu_read_lock();
    list_for_each_entry_rcu(pnd, &pndevs->list, list) {
        u8 addr;

        if (dev_idx > dev_start_idx)
            addr_start_idx = 0;
        if (dev_idx++ < dev_start_idx)
            continue;

        addr_idx = 0;
        for_each_set_bit(addr, pnd->addrs, 64) {
            if (addr_idx++ < addr_start_idx)
                continue;

            if (fill_addr(skb, pnd->netdev, addr << 2,
                     NETLINK_CB(cb->skb).portid,
                    cb->nlh->nlmsg_seq, RTM_NEWADDR) < 0)
                goto out;
        }
    }

out:
    rcu_read_unlock();
    cb->args[0] = dev_idx;
    cb->args[1] = addr_idx;

    return skb->len;
}

/* Routes handling */

static int fill_route(struct sk_buff *skb, struct net_device *dev, u8 dst,
            u32 portid, u32 seq, int event)
{
    struct rtmsg *rtm;
    struct nlmsghdr *nlh;

    nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), 0);
    if (nlh == NULL)
        return -EMSGSIZE;

    rtm = nlmsg_data(nlh);
    rtm->rtm_family = AF_PHONET;
    rtm->rtm_dst_len = 6;
    rtm->rtm_src_len = 0;
    rtm->rtm_tos = 0;
    rtm->rtm_table = RT_TABLE_MAIN;
    rtm->rtm_protocol = RTPROT_STATIC;
    rtm->rtm_scope = RT_SCOPE_UNIVERSE;
    rtm->rtm_type = RTN_UNICAST;
    rtm->rtm_flags = 0;
    if (nla_put_u8(skb, RTA_DST, dst) ||
        nla_put_u32(skb, RTA_OIF, dev->ifindex))
        goto nla_put_failure;
    return nlmsg_end(skb, nlh);

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

void rtm_phonet_notify(int event, struct net_device *dev, u8 dst)
{
    struct sk_buff *skb;
    int err = -ENOBUFS;

    skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
            nla_total_size(1) + nla_total_size(4), GFP_KERNEL);
    if (skb == NULL)
        goto errout;
    err = fill_route(skb, dev, dst, 0, 0, event);
    if (err < 0) {
        WARN_ON(err == -EMSGSIZE);
        kfree_skb(skb);
        goto errout;
    }
    rtnl_notify(skb, dev_net(dev), 0,
              RTNLGRP_PHONET_ROUTE, NULL, GFP_KERNEL);
    return;
errout:
    rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_ROUTE, err);
}

static const struct nla_policy rtm_phonet_policy[RTA_MAX+1] = {
    [RTA_DST] = { .type = NLA_U8 },
    [RTA_OIF] = { .type = NLA_U32 },
};

static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh, void *attr)
{
    struct net *net = sock_net(skb->sk);
    struct nlattr *tb[RTA_MAX+1];
    struct net_device *dev;
    struct rtmsg *rtm;
    int err;
    u8 dst;

    if (!capable(CAP_SYS_ADMIN))
        return -EPERM;

    ASSERT_RTNL();

    err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_phonet_policy);
    if (err < 0)
        return err;

    rtm = nlmsg_data(nlh);
    if (rtm->rtm_table != RT_TABLE_MAIN || rtm->rtm_type != RTN_UNICAST)
        return -EINVAL;
    if (tb[RTA_DST] == NULL || tb[RTA_OIF] == NULL)
        return -EINVAL;
    dst = nla_get_u8(tb[RTA_DST]);
    if (dst & 3) /* Phonet addresses only have 6 high-order bits */
        return -EINVAL;

    dev = __dev_get_by_index(net, nla_get_u32(tb[RTA_OIF]));
    if (dev == NULL)
        return -ENODEV;

    if (nlh->nlmsg_type == RTM_NEWROUTE)
        err = phonet_route_add(dev, dst);
    else
        err = phonet_route_del(dev, dst);
    if (!err)
        rtm_phonet_notify(nlh->nlmsg_type, dev, dst);
    return err;
}

static int route_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
{
    struct net *net = sock_net(skb->sk);
    u8 addr, addr_idx = 0, addr_start_idx = cb->args[0];

    rcu_read_lock();
    for (addr = 0; addr < 64; addr++) {
        struct net_device *dev;

        dev = phonet_route_get_rcu(net, addr << 2);
        if (!dev)
            continue;

        if (addr_idx++ < addr_start_idx)
            continue;
        if (fill_route(skb, dev, addr << 2, NETLINK_CB(cb->skb).portid,
                cb->nlh->nlmsg_seq, RTM_NEWROUTE))
            goto out;
    }

out:
    rcu_read_unlock();
    cb->args[0] = addr_idx;
    cb->args[1] = 0;

    return skb->len;
}

int __init phonet_netlink_register(void)
{
    int err = __rtnl_register(PF_PHONET, RTM_NEWADDR, addr_doit,
                  NULL, NULL);
    if (err)
        return err;

    /* Further __rtnl_register() cannot fail */
    __rtnl_register(PF_PHONET, RTM_DELADDR, addr_doit, NULL, NULL);
    __rtnl_register(PF_PHONET, RTM_GETADDR, NULL, getaddr_dumpit, NULL);
    __rtnl_register(PF_PHONET, RTM_NEWROUTE, route_doit, NULL, NULL);
    __rtnl_register(PF_PHONET, RTM_DELROUTE, route_doit, NULL, NULL);
    __rtnl_register(PF_PHONET, RTM_GETROUTE, NULL, route_dumpit, NULL);
    return 0;
}