dn_dev.c

linux 内核源代码

int dn_dev_ioctl(unsigned int cmd, void __user *arg)
{
	char buffer[DN_IFREQ_SIZE];
	struct ifreq *ifr = (struct ifreq *)buffer;
	struct sockaddr_dn *sdn = (struct sockaddr_dn *)&ifr->ifr_addr;
	struct dn_dev *dn_db;
	struct net_device *dev;
	struct dn_ifaddr *ifa = NULL, **ifap = NULL;
	int ret = 0;

	if (copy_from_user(ifr, arg, DN_IFREQ_SIZE))
		return -EFAULT;
	ifr->ifr_name[IFNAMSIZ-1] = 0;

#ifdef CONFIG_KMOD
	dev_load(&init_net, ifr->ifr_name);
#endif

	switch(cmd) {
		case SIOCGIFADDR:
			break;
		case SIOCSIFADDR:
			if (!capable(CAP_NET_ADMIN))
				return -EACCES;
			if (sdn->sdn_family != AF_DECnet)
				return -EINVAL;
			break;
		default:
			return -EINVAL;
	}

	rtnl_lock();

	if ((dev = __dev_get_by_name(&init_net, ifr->ifr_name)) == NULL) {
		ret = -ENODEV;
		goto done;
	}

	if ((dn_db = dev->dn_ptr) != NULL) {
		for (ifap = &dn_db->ifa_list; (ifa=*ifap) != NULL; ifap = &ifa->ifa_next)
			if (strcmp(ifr->ifr_name, ifa->ifa_label) == 0)
				break;
	}

	if (ifa == NULL && cmd != SIOCSIFADDR) {
		ret = -EADDRNOTAVAIL;
		goto done;
	}

	switch(cmd) {
		case SIOCGIFADDR:
			*((__le16 *)sdn->sdn_nodeaddr) = ifa->ifa_local;
			goto rarok;

		case SIOCSIFADDR:
			if (!ifa) {
				if ((ifa = dn_dev_alloc_ifa()) == NULL) {
					ret = -ENOBUFS;
					break;
				}
				memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
			} else {
				if (ifa->ifa_local == dn_saddr2dn(sdn))
					break;
				dn_dev_del_ifa(dn_db, ifap, 0);
			}

			ifa->ifa_local = ifa->ifa_address = dn_saddr2dn(sdn);

			ret = dn_dev_set_ifa(dev, ifa);
	}
done:
	rtnl_unlock();

	return ret;
rarok:
	if (copy_to_user(arg, ifr, DN_IFREQ_SIZE))
		ret = -EFAULT;
	goto done;
}

struct net_device *dn_dev_get_default(void)
{
	struct net_device *dev;
	read_lock(&dndev_lock);
	dev = decnet_default_device;
	if (dev) {
		if (dev->dn_ptr)
			dev_hold(dev);
		else
			dev = NULL;
	}
	read_unlock(&dndev_lock);
	return dev;
}

int dn_dev_set_default(struct net_device *dev, int force)
{
	struct net_device *old = NULL;
	int rv = -EBUSY;
	if (!dev->dn_ptr)
		return -ENODEV;
	write_lock(&dndev_lock);
	if (force || decnet_default_device == NULL) {
		old = decnet_default_device;
		decnet_default_device = dev;
		rv = 0;
	}
	write_unlock(&dndev_lock);
	if (old)
		dev_put(old);
	return rv;
}

static void dn_dev_check_default(struct net_device *dev)
{
	write_lock(&dndev_lock);
	if (dev == decnet_default_device) {
		decnet_default_device = NULL;
	} else {
		dev = NULL;
	}
	write_unlock(&dndev_lock);
	if (dev)
		dev_put(dev);
}

static struct dn_dev *dn_dev_by_index(int ifindex)
{
	struct net_device *dev;
	struct dn_dev *dn_dev = NULL;
	dev = dev_get_by_index(&init_net, ifindex);
	if (dev) {
		dn_dev = dev->dn_ptr;
		dev_put(dev);
	}

	return dn_dev;
}

static const struct nla_policy dn_ifa_policy[IFA_MAX+1] = {
	[IFA_ADDRESS]		= { .type = NLA_U16 },
	[IFA_LOCAL]		= { .type = NLA_U16 },
	[IFA_LABEL]		= { .type = NLA_STRING,
				    .len = IFNAMSIZ - 1 },
};

static int dn_nl_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
	struct nlattr *tb[IFA_MAX+1];
	struct dn_dev *dn_db;
	struct ifaddrmsg *ifm;
	struct dn_ifaddr *ifa, **ifap;
	int err;

	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, dn_ifa_policy);
	if (err < 0)
		goto errout;

	err = -ENODEV;
	ifm = nlmsg_data(nlh);
	if ((dn_db = dn_dev_by_index(ifm->ifa_index)) == NULL)
		goto errout;

	err = -EADDRNOTAVAIL;
	for (ifap = &dn_db->ifa_list; (ifa = *ifap); ifap = &ifa->ifa_next) {
		if (tb[IFA_LOCAL] &&
		    nla_memcmp(tb[IFA_LOCAL], &ifa->ifa_local, 2))
			continue;

		if (tb[IFA_LABEL] && nla_strcmp(tb[IFA_LABEL], ifa->ifa_label))
			continue;

		dn_dev_del_ifa(dn_db, ifap, 1);
		return 0;
	}

errout:
	return err;
}

static int dn_nl_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
	struct nlattr *tb[IFA_MAX+1];
	struct net_device *dev;
	struct dn_dev *dn_db;
	struct ifaddrmsg *ifm;
	struct dn_ifaddr *ifa;
	int err;

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

	if (tb[IFA_LOCAL] == NULL)
		return -EINVAL;

	ifm = nlmsg_data(nlh);
	if ((dev = __dev_get_by_index(&init_net, ifm->ifa_index)) == NULL)
		return -ENODEV;

	if ((dn_db = dev->dn_ptr) == NULL) {
		int err;
		dn_db = dn_dev_create(dev, &err);
		if (!dn_db)
			return err;
	}

	if ((ifa = dn_dev_alloc_ifa()) == NULL)
		return -ENOBUFS;

	if (tb[IFA_ADDRESS] == NULL)
		tb[IFA_ADDRESS] = tb[IFA_LOCAL];

	ifa->ifa_local = nla_get_le16(tb[IFA_LOCAL]);
	ifa->ifa_address = nla_get_le16(tb[IFA_ADDRESS]);
	ifa->ifa_flags = ifm->ifa_flags;
	ifa->ifa_scope = ifm->ifa_scope;
	ifa->ifa_dev = dn_db;

	if (tb[IFA_LABEL])
		nla_strlcpy(ifa->ifa_label, tb[IFA_LABEL], IFNAMSIZ);
	else
		memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);

	err = dn_dev_insert_ifa(dn_db, ifa);
	if (err)
		dn_dev_free_ifa(ifa);

	return err;
}

static inline size_t dn_ifaddr_nlmsg_size(void)
{
	return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
	       + nla_total_size(IFNAMSIZ) /* IFA_LABEL */
	       + nla_total_size(2) /* IFA_ADDRESS */
	       + nla_total_size(2); /* IFA_LOCAL */
}

static int dn_nl_fill_ifaddr(struct sk_buff *skb, struct dn_ifaddr *ifa,
			     u32 pid, u32 seq, int event, unsigned int flags)
{
	struct ifaddrmsg *ifm;
	struct nlmsghdr *nlh;

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

	ifm = nlmsg_data(nlh);
	ifm->ifa_family = AF_DECnet;
	ifm->ifa_prefixlen = 16;
	ifm->ifa_flags = ifa->ifa_flags | IFA_F_PERMANENT;
	ifm->ifa_scope = ifa->ifa_scope;
	ifm->ifa_index = ifa->ifa_dev->dev->ifindex;

	if (ifa->ifa_address)
		NLA_PUT_LE16(skb, IFA_ADDRESS, ifa->ifa_address);
	if (ifa->ifa_local)
		NLA_PUT_LE16(skb, IFA_LOCAL, ifa->ifa_local);
	if (ifa->ifa_label[0])
		NLA_PUT_STRING(skb, IFA_LABEL, ifa->ifa_label);

	return nlmsg_end(skb, nlh);

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

static void dn_ifaddr_notify(int event, struct dn_ifaddr *ifa)
{
	struct sk_buff *skb;
	int err = -ENOBUFS;

	skb = alloc_skb(dn_ifaddr_nlmsg_size(), GFP_KERNEL);
	if (skb == NULL)
		goto errout;

	err = dn_nl_fill_ifaddr(skb, ifa, 0, 0, event, 0);
	if (err < 0) {
		/* -EMSGSIZE implies BUG in dn_ifaddr_nlmsg_size() */
		WARN_ON(err == -EMSGSIZE);
		kfree_skb(skb);
		goto errout;
	}
	err = rtnl_notify(skb, 0, RTNLGRP_DECnet_IFADDR, NULL, GFP_KERNEL);
errout:
	if (err < 0)
		rtnl_set_sk_err(RTNLGRP_DECnet_IFADDR, err);
}

static int dn_nl_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
{
	int idx, dn_idx = 0, skip_ndevs, skip_naddr;
	struct net_device *dev;
	struct dn_dev *dn_db;
	struct dn_ifaddr *ifa;

	skip_ndevs = cb->args[0];
	skip_naddr = cb->args[1];

	idx = 0;
	for_each_netdev(&init_net, dev) {
		if (idx < skip_ndevs)
			goto cont;
		else if (idx > skip_ndevs) {
			/* Only skip over addresses for first dev dumped
			 * in this iteration (idx == skip_ndevs) */
			skip_naddr = 0;
		}

		if ((dn_db = dev->dn_ptr) == NULL)
			goto cont;

		for (ifa = dn_db->ifa_list, dn_idx = 0; ifa;
		     ifa = ifa->ifa_next, dn_idx++) {
			if (dn_idx < skip_naddr)
				continue;

			if (dn_nl_fill_ifaddr(skb, ifa, NETLINK_CB(cb->skb).pid,
					      cb->nlh->nlmsg_seq, RTM_NEWADDR,
					      NLM_F_MULTI) < 0)
				goto done;
		}
cont:
		idx++;
	}
done:
	cb->args[0] = idx;
	cb->args[1] = dn_idx;

	return skb->len;
}

static int dn_dev_get_first(struct net_device *dev, __le16 *addr)
{
	struct dn_dev *dn_db = (struct dn_dev *)dev->dn_ptr;
	struct dn_ifaddr *ifa;
	int rv = -ENODEV;
	if (dn_db == NULL)
		goto out;
	ifa = dn_db->ifa_list;
	if (ifa != NULL) {
		*addr = ifa->ifa_local;
		rv = 0;
	}
out:
	return rv;
}

/*
 * Find a default address to bind to.
 *
 * This is one of those areas where the initial VMS concepts don't really
 * map onto the Linux concepts, and since we introduced multiple addresses
 * per interface we have to cope with slightly odd ways of finding out what
 * "our address" really is. Mostly it's not a problem; for this we just guess
 * a sensible default. Eventually the routing code will take care of all the
 * nasties for us I hope.
 */
int dn_dev_bind_default(__le16 *addr)
{
	struct net_device *dev;
	int rv;
	dev = dn_dev_get_default();
last_chance:
	if (dev) {
		read_lock(&dev_base_lock);
		rv = dn_dev_get_first(dev, addr);
		read_unlock(&dev_base_lock);
		dev_put(dev);
		if (rv == 0 || dev == init_net.loopback_dev)
			return rv;
	}
	dev = init_net.loopback_dev;
	dev_hold(dev);
	goto last_chance;
}

static void dn_send_endnode_hello(struct net_device *dev, struct dn_ifaddr *ifa)
{
	struct endnode_hello_message *msg;
	struct sk_buff *skb = NULL;
	__le16 *pktlen;
	struct dn_dev *dn_db = (struct dn_dev *)dev->dn_ptr;

	if ((skb = dn_alloc_skb(NULL, sizeof(*msg), GFP_ATOMIC)) == NULL)
		return;

	skb->dev = dev;

	msg = (struct endnode_hello_message *)skb_put(skb,sizeof(*msg));

	msg->msgflg  = 0x0D;
	memcpy(msg->tiver, dn_eco_version, 3);
	dn_dn2eth(msg->id, ifa->ifa_local);
	msg->iinfo   = DN_RT_INFO_ENDN;
	msg->blksize = dn_htons(mtu2blksize(dev));
	msg->area    = 0x00;
	memset(msg->seed, 0, 8);
	memcpy(msg->neighbor, dn_hiord, ETH_ALEN);

	if (dn_db->router) {
		struct dn_neigh *dn = (struct dn_neigh *)dn_db->router;
		dn_dn2eth(msg->neighbor, dn->addr);
	}

	msg->timer   = dn_htons((unsigned short)dn_db->parms.t3);
	msg->mpd     = 0x00;
	msg->datalen = 0x02;
	memset(msg->data, 0xAA, 2);

	pktlen = (__le16 *)skb_push(skb,2);
	*pktlen = dn_htons(skb->len - 2);

	skb_reset_network_header(skb);

	dn_rt_finish_output(skb, dn_rt_all_rt_mcast, msg->id);
}


#define DRDELAY (5 * HZ)

static int dn_am_i_a_router(struct dn_neigh *dn, struct dn_dev *dn_db, struct dn_ifaddr *ifa)
{
	/* First check time since device went up */
	if ((jiffies - dn_db->uptime) < DRDELAY)
		return 0;

	/* If there is no router, then yes... */
	if (!dn_db->router)
		return 1;

	/* otherwise only if we have a higher priority or.. */
	if (dn->priority < dn_db->parms.priority)
		return 1;

	/* if we have equal priority and a higher node number */
	if (dn->priority != dn_db->parms.priority)
		return 0;

	if (dn_ntohs(dn->addr) < dn_ntohs(ifa->ifa_local))
		return 1;

	return 0;
}

static void dn_send_router_hello(struct net_device *dev, struct dn_ifaddr *ifa)
{
	int n;
	struct dn_dev *dn_db = dev->dn_ptr;
	struct dn_neigh *dn = (struct dn_neigh *)dn_db->router;
	struct sk_buff *skb;
	size_t size;
	unsigned char *ptr;
	unsigned char *i1, *i2;
	__le16 *pktlen;
	char *src;

	if (mtu2blksize(dev) < (26 + 7))
		return;

	n = mtu2blksize(dev) - 26;
	n /= 7;

	if (n > 32)
		n = 32;

	size = 2 + 26 + 7 * n;

	if ((skb = dn_alloc_skb(NULL, size, GFP_ATOMIC)) == NULL)
		return;

	skb->dev = dev;
	ptr = skb_put(skb, size);

	*ptr++ = DN_RT_PKT_CNTL | DN_RT_PKT_ERTH;
	*ptr++ = 2; /* ECO */
	*ptr++ = 0;
	*ptr++ = 0;
	dn_dn2eth(ptr, ifa->ifa_local);
	src = ptr;
	ptr += ETH_ALEN;
	*ptr++ = dn_db->parms.forwarding == 1 ?
			DN_RT_INFO_L1RT : DN_RT_INFO_L2RT;
	*((__le16 *)ptr) = dn_htons(mtu2blksize(dev));
	ptr += 2;
	*ptr++ = dn_db->parms.priority; /* Priority */
	*ptr++ = 0; /* Area: Reserved */
	*((__le16 *)ptr) = dn_htons((unsigned short)dn_db->parms.t3);
	ptr += 2;
	*ptr++ = 0; /* MPD: Reserved */
	i1 = ptr++;
	memset(ptr, 0, 7); /* Name: Reserved */