/*
   * File: pn_netlink.c
   *
   * Phonet netlink interface
   *
   * Copyright (C) 2008 Nokia Corporation.
   *
   * Authors: Sakari Ailus <sakari.ailus@nokia.com>
   *          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)
  {
  	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 (!netlink_capable(skb, CAP_NET_ADMIN))
  		return -EPERM;
  
  	if (!netlink_capable(skb, 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)
  {
  	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 (!netlink_capable(skb, CAP_NET_ADMIN))
  		return -EPERM;
  
  	if (!netlink_capable(skb, 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;
  }