af_mpls.c 26.4 KB
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#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
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#include <linux/sysctl.h>
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#include <linux/net.h>
#include <linux/module.h>
#include <linux/if_arp.h>
#include <linux/ipv6.h>
#include <linux/mpls.h>
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#include <linux/vmalloc.h>
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#include <net/ip.h>
#include <net/dst.h>
#include <net/sock.h>
#include <net/arp.h>
#include <net/ip_fib.h>
#include <net/netevent.h>
#include <net/netns/generic.h>
#include "internal.h"

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#define LABEL_NOT_SPECIFIED (1<<20)
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#define MAX_NEW_LABELS 2

/* This maximum ha length copied from the definition of struct neighbour */
#define MAX_VIA_ALEN (ALIGN(MAX_ADDR_LEN, sizeof(unsigned long)))

struct mpls_route { /* next hop label forwarding entry */
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	struct net_device __rcu *rt_dev;
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	struct rcu_head		rt_rcu;
	u32			rt_label[MAX_NEW_LABELS];
	u8			rt_protocol; /* routing protocol that set this entry */
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	u8			rt_labels;
	u8			rt_via_alen;
	u8			rt_via_table;
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	u8			rt_via[0];
};

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static int zero = 0;
static int label_limit = (1 << 20) - 1;

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static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt,
		       struct nlmsghdr *nlh, struct net *net, u32 portid,
		       unsigned int nlm_flags);

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static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned index)
{
	struct mpls_route *rt = NULL;

	if (index < net->mpls.platform_labels) {
		struct mpls_route __rcu **platform_label =
			rcu_dereference(net->mpls.platform_label);
		rt = rcu_dereference(platform_label[index]);
	}
	return rt;
}

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static inline struct mpls_dev *mpls_dev_get(const struct net_device *dev)
{
	return rcu_dereference_rtnl(dev->mpls_ptr);
}

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static bool mpls_output_possible(const struct net_device *dev)
{
	return dev && (dev->flags & IFF_UP) && netif_carrier_ok(dev);
}

static unsigned int mpls_rt_header_size(const struct mpls_route *rt)
{
	/* The size of the layer 2.5 labels to be added for this route */
	return rt->rt_labels * sizeof(struct mpls_shim_hdr);
}

static unsigned int mpls_dev_mtu(const struct net_device *dev)
{
	/* The amount of data the layer 2 frame can hold */
	return dev->mtu;
}

static bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
{
	if (skb->len <= mtu)
		return false;

	if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu)
		return false;

	return true;
}

static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb,
			struct mpls_entry_decoded dec)
{
	/* RFC4385 and RFC5586 encode other packets in mpls such that
	 * they don't conflict with the ip version number, making
	 * decoding by examining the ip version correct in everything
	 * except for the strangest cases.
	 *
	 * The strange cases if we choose to support them will require
	 * manual configuration.
	 */
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	struct iphdr *hdr4;
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	bool success = true;

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	/* The IPv4 code below accesses through the IPv4 header
	 * checksum, which is 12 bytes into the packet.
	 * The IPv6 code below accesses through the IPv6 hop limit
	 * which is 8 bytes into the packet.
	 *
	 * For all supported cases there should always be at least 12
	 * bytes of packet data present.  The IPv4 header is 20 bytes
	 * without options and the IPv6 header is always 40 bytes
	 * long.
	 */
	if (!pskb_may_pull(skb, 12))
		return false;

	/* Use ip_hdr to find the ip protocol version */
	hdr4 = ip_hdr(skb);
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	if (hdr4->version == 4) {
		skb->protocol = htons(ETH_P_IP);
		csum_replace2(&hdr4->check,
			      htons(hdr4->ttl << 8),
			      htons(dec.ttl << 8));
		hdr4->ttl = dec.ttl;
	}
	else if (hdr4->version == 6) {
		struct ipv6hdr *hdr6 = ipv6_hdr(skb);
		skb->protocol = htons(ETH_P_IPV6);
		hdr6->hop_limit = dec.ttl;
	}
	else
		/* version 0 and version 1 are used by pseudo wires */
		success = false;
	return success;
}

static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
			struct packet_type *pt, struct net_device *orig_dev)
{
	struct net *net = dev_net(dev);
	struct mpls_shim_hdr *hdr;
	struct mpls_route *rt;
	struct mpls_entry_decoded dec;
	struct net_device *out_dev;
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	struct mpls_dev *mdev;
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	unsigned int hh_len;
	unsigned int new_header_size;
	unsigned int mtu;
	int err;

	/* Careful this entire function runs inside of an rcu critical section */

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	mdev = mpls_dev_get(dev);
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	if (!mdev || !mdev->input_enabled)
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		goto drop;

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	if (skb->pkt_type != PACKET_HOST)
		goto drop;

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
		goto drop;

	if (!pskb_may_pull(skb, sizeof(*hdr)))
		goto drop;

	/* Read and decode the label */
	hdr = mpls_hdr(skb);
	dec = mpls_entry_decode(hdr);

	/* Pop the label */
	skb_pull(skb, sizeof(*hdr));
	skb_reset_network_header(skb);

	skb_orphan(skb);

	rt = mpls_route_input_rcu(net, dec.label);
	if (!rt)
		goto drop;

	/* Find the output device */
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	out_dev = rcu_dereference(rt->rt_dev);
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	if (!mpls_output_possible(out_dev))
		goto drop;

	if (skb_warn_if_lro(skb))
		goto drop;

	skb_forward_csum(skb);

	/* Verify ttl is valid */
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	if (dec.ttl <= 1)
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		goto drop;
	dec.ttl -= 1;

	/* Verify the destination can hold the packet */
	new_header_size = mpls_rt_header_size(rt);
	mtu = mpls_dev_mtu(out_dev);
	if (mpls_pkt_too_big(skb, mtu - new_header_size))
		goto drop;

	hh_len = LL_RESERVED_SPACE(out_dev);
	if (!out_dev->header_ops)
		hh_len = 0;

	/* Ensure there is enough space for the headers in the skb */
	if (skb_cow(skb, hh_len + new_header_size))
		goto drop;

	skb->dev = out_dev;
	skb->protocol = htons(ETH_P_MPLS_UC);

	if (unlikely(!new_header_size && dec.bos)) {
		/* Penultimate hop popping */
		if (!mpls_egress(rt, skb, dec))
			goto drop;
	} else {
		bool bos;
		int i;
		skb_push(skb, new_header_size);
		skb_reset_network_header(skb);
		/* Push the new labels */
		hdr = mpls_hdr(skb);
		bos = dec.bos;
		for (i = rt->rt_labels - 1; i >= 0; i--) {
			hdr[i] = mpls_entry_encode(rt->rt_label[i], dec.ttl, 0, bos);
			bos = false;
		}
	}

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	err = neigh_xmit(rt->rt_via_table, out_dev, rt->rt_via, skb);
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	if (err)
		net_dbg_ratelimited("%s: packet transmission failed: %d\n",
				    __func__, err);
	return 0;

drop:
	kfree_skb(skb);
	return NET_RX_DROP;
}

static struct packet_type mpls_packet_type __read_mostly = {
	.type = cpu_to_be16(ETH_P_MPLS_UC),
	.func = mpls_forward,
};

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

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struct mpls_route_config {
	u32		rc_protocol;
	u32		rc_ifindex;
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	u16		rc_via_table;
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	u16		rc_via_alen;
	u8		rc_via[MAX_VIA_ALEN];
	u32		rc_label;
	u32		rc_output_labels;
	u32		rc_output_label[MAX_NEW_LABELS];
	u32		rc_nlflags;
	struct nl_info	rc_nlinfo;
};

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static struct mpls_route *mpls_rt_alloc(size_t alen)
{
	struct mpls_route *rt;

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	rt = kzalloc(sizeof(*rt) + alen, GFP_KERNEL);
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	if (rt)
		rt->rt_via_alen = alen;
	return rt;
}

static void mpls_rt_free(struct mpls_route *rt)
{
	if (rt)
		kfree_rcu(rt, rt_rcu);
}

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static void mpls_notify_route(struct net *net, unsigned index,
			      struct mpls_route *old, struct mpls_route *new,
			      const struct nl_info *info)
{
	struct nlmsghdr *nlh = info ? info->nlh : NULL;
	unsigned portid = info ? info->portid : 0;
	int event = new ? RTM_NEWROUTE : RTM_DELROUTE;
	struct mpls_route *rt = new ? new : old;
	unsigned nlm_flags = (old && new) ? NLM_F_REPLACE : 0;
	/* Ignore reserved labels for now */
	if (rt && (index >= 16))
		rtmsg_lfib(event, index, rt, nlh, net, portid, nlm_flags);
}

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static void mpls_route_update(struct net *net, unsigned index,
			      struct net_device *dev, struct mpls_route *new,
			      const struct nl_info *info)
{
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	struct mpls_route __rcu **platform_label;
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	struct mpls_route *rt, *old = NULL;

	ASSERT_RTNL();

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	platform_label = rtnl_dereference(net->mpls.platform_label);
	rt = rtnl_dereference(platform_label[index]);
	if (!dev || (rt && (rtnl_dereference(rt->rt_dev) == dev))) {
		rcu_assign_pointer(platform_label[index], new);
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		old = rt;
	}

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	mpls_notify_route(net, index, old, new, info);

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	/* If we removed a route free it now */
	mpls_rt_free(old);
}

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static unsigned find_free_label(struct net *net)
{
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	struct mpls_route __rcu **platform_label;
	size_t platform_labels;
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	unsigned index;
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	platform_label = rtnl_dereference(net->mpls.platform_label);
	platform_labels = net->mpls.platform_labels;
	for (index = 16; index < platform_labels; index++) {
		if (!rtnl_dereference(platform_label[index]))
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			return index;
	}
	return LABEL_NOT_SPECIFIED;
}

static int mpls_route_add(struct mpls_route_config *cfg)
{
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	struct mpls_route __rcu **platform_label;
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	struct net *net = cfg->rc_nlinfo.nl_net;
	struct net_device *dev = NULL;
	struct mpls_route *rt, *old;
	unsigned index;
	int i;
	int err = -EINVAL;

	index = cfg->rc_label;

	/* If a label was not specified during insert pick one */
	if ((index == LABEL_NOT_SPECIFIED) &&
	    (cfg->rc_nlflags & NLM_F_CREATE)) {
		index = find_free_label(net);
	}

	/* The first 16 labels are reserved, and may not be set */
	if (index < 16)
		goto errout;

	/* The full 20 bit range may not be supported. */
	if (index >= net->mpls.platform_labels)
		goto errout;

	/* Ensure only a supported number of labels are present */
	if (cfg->rc_output_labels > MAX_NEW_LABELS)
		goto errout;

	err = -ENODEV;
	dev = dev_get_by_index(net, cfg->rc_ifindex);
	if (!dev)
		goto errout;

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	/* Ensure this is a supported device */
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	err = -EINVAL;
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	if (!mpls_dev_get(dev))
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		goto errout;

	err = -EINVAL;
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	if ((cfg->rc_via_table == NEIGH_LINK_TABLE) &&
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	    (dev->addr_len != cfg->rc_via_alen))
		goto errout;

	/* Append makes no sense with mpls */
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	err = -EOPNOTSUPP;
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	if (cfg->rc_nlflags & NLM_F_APPEND)
		goto errout;

	err = -EEXIST;
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	platform_label = rtnl_dereference(net->mpls.platform_label);
	old = rtnl_dereference(platform_label[index]);
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	if ((cfg->rc_nlflags & NLM_F_EXCL) && old)
		goto errout;

	err = -EEXIST;
	if (!(cfg->rc_nlflags & NLM_F_REPLACE) && old)
		goto errout;

	err = -ENOENT;
	if (!(cfg->rc_nlflags & NLM_F_CREATE) && !old)
		goto errout;

	err = -ENOMEM;
	rt = mpls_rt_alloc(cfg->rc_via_alen);
	if (!rt)
		goto errout;

	rt->rt_labels = cfg->rc_output_labels;
	for (i = 0; i < rt->rt_labels; i++)
		rt->rt_label[i] = cfg->rc_output_label[i];
	rt->rt_protocol = cfg->rc_protocol;
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	RCU_INIT_POINTER(rt->rt_dev, dev);
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	rt->rt_via_table = cfg->rc_via_table;
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	memcpy(rt->rt_via, cfg->rc_via, cfg->rc_via_alen);

	mpls_route_update(net, index, NULL, rt, &cfg->rc_nlinfo);

	dev_put(dev);
	return 0;

errout:
	if (dev)
		dev_put(dev);
	return err;
}

static int mpls_route_del(struct mpls_route_config *cfg)
{
	struct net *net = cfg->rc_nlinfo.nl_net;
	unsigned index;
	int err = -EINVAL;

	index = cfg->rc_label;

	/* The first 16 labels are reserved, and may not be removed */
	if (index < 16)
		goto errout;

	/* The full 20 bit range may not be supported */
	if (index >= net->mpls.platform_labels)
		goto errout;

	mpls_route_update(net, index, NULL, NULL, &cfg->rc_nlinfo);

	err = 0;
errout:
	return err;
}

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#define MPLS_PERDEV_SYSCTL_OFFSET(field)	\
	(&((struct mpls_dev *)0)->field)

static const struct ctl_table mpls_dev_table[] = {
	{
		.procname	= "input",
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
		.data		= MPLS_PERDEV_SYSCTL_OFFSET(input_enabled),
	},
	{ }
};

static int mpls_dev_sysctl_register(struct net_device *dev,
				    struct mpls_dev *mdev)
{
	char path[sizeof("net/mpls/conf/") + IFNAMSIZ];
	struct ctl_table *table;
	int i;

	table = kmemdup(&mpls_dev_table, sizeof(mpls_dev_table), GFP_KERNEL);
	if (!table)
		goto out;

	/* Table data contains only offsets relative to the base of
	 * the mdev at this point, so make them absolute.
	 */
	for (i = 0; i < ARRAY_SIZE(mpls_dev_table); i++)
		table[i].data = (char *)mdev + (uintptr_t)table[i].data;

	snprintf(path, sizeof(path), "net/mpls/conf/%s", dev->name);

	mdev->sysctl = register_net_sysctl(dev_net(dev), path, table);
	if (!mdev->sysctl)
		goto free;

	return 0;

free:
	kfree(table);
out:
	return -ENOBUFS;
}

static void mpls_dev_sysctl_unregister(struct mpls_dev *mdev)
{
	struct ctl_table *table;

	table = mdev->sysctl->ctl_table_arg;
	unregister_net_sysctl_table(mdev->sysctl);
	kfree(table);
}

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static struct mpls_dev *mpls_add_dev(struct net_device *dev)
{
	struct mpls_dev *mdev;
	int err = -ENOMEM;

	ASSERT_RTNL();

	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
	if (!mdev)
		return ERR_PTR(err);

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	err = mpls_dev_sysctl_register(dev, mdev);
	if (err)
		goto free;

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	rcu_assign_pointer(dev->mpls_ptr, mdev);

	return mdev;
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free:
	kfree(mdev);
	return ERR_PTR(err);
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}

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static void mpls_ifdown(struct net_device *dev)
{
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	struct mpls_route __rcu **platform_label;
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	struct net *net = dev_net(dev);
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	struct mpls_dev *mdev;
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	unsigned index;

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	platform_label = rtnl_dereference(net->mpls.platform_label);
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	for (index = 0; index < net->mpls.platform_labels; index++) {
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		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
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		if (!rt)
			continue;
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		if (rtnl_dereference(rt->rt_dev) != dev)
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			continue;
		rt->rt_dev = NULL;
	}
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	mdev = mpls_dev_get(dev);
	if (!mdev)
		return;

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	mpls_dev_sysctl_unregister(mdev);

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	RCU_INIT_POINTER(dev->mpls_ptr, NULL);

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	kfree_rcu(mdev, rcu);
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}

static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
			   void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
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	struct mpls_dev *mdev;
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	switch(event) {
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	case NETDEV_REGISTER:
		/* For now just support ethernet devices */
		if ((dev->type == ARPHRD_ETHER) ||
		    (dev->type == ARPHRD_LOOPBACK)) {
			mdev = mpls_add_dev(dev);
			if (IS_ERR(mdev))
				return notifier_from_errno(PTR_ERR(mdev));
		}
		break;

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	case NETDEV_UNREGISTER:
		mpls_ifdown(dev);
		break;
	}
	return NOTIFY_OK;
}

static struct notifier_block mpls_dev_notifier = {
	.notifier_call = mpls_dev_notify,
};

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static int nla_put_via(struct sk_buff *skb,
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		       u8 table, const void *addr, int alen)
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{
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	static const int table_to_family[NEIGH_NR_TABLES + 1] = {
		AF_INET, AF_INET6, AF_DECnet, AF_PACKET,
	};
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	struct nlattr *nla;
	struct rtvia *via;
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	int family = AF_UNSPEC;
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	nla = nla_reserve(skb, RTA_VIA, alen + 2);
	if (!nla)
		return -EMSGSIZE;

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	if (table <= NEIGH_NR_TABLES)
		family = table_to_family[table];

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	via = nla_data(nla);
	via->rtvia_family = family;
	memcpy(via->rtvia_addr, addr, alen);
	return 0;
}

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int nla_put_labels(struct sk_buff *skb, int attrtype,
		   u8 labels, const u32 label[])
{
	struct nlattr *nla;
	struct mpls_shim_hdr *nla_label;
	bool bos;
	int i;
	nla = nla_reserve(skb, attrtype, labels*4);
	if (!nla)
		return -EMSGSIZE;

	nla_label = nla_data(nla);
	bos = true;
	for (i = labels - 1; i >= 0; i--) {
		nla_label[i] = mpls_entry_encode(label[i], 0, 0, bos);
		bos = false;
	}

	return 0;
}

int nla_get_labels(const struct nlattr *nla,
		   u32 max_labels, u32 *labels, u32 label[])
{
	unsigned len = nla_len(nla);
	unsigned nla_labels;
	struct mpls_shim_hdr *nla_label;
	bool bos;
	int i;

	/* len needs to be an even multiple of 4 (the label size) */
	if (len & 3)
		return -EINVAL;

	/* Limit the number of new labels allowed */
	nla_labels = len/4;
	if (nla_labels > max_labels)
		return -EINVAL;

	nla_label = nla_data(nla);
	bos = true;
	for (i = nla_labels - 1; i >= 0; i--, bos = false) {
		struct mpls_entry_decoded dec;
		dec = mpls_entry_decode(nla_label + i);

		/* Ensure the bottom of stack flag is properly set
		 * and ttl and tc are both clear.
		 */
		if ((dec.bos != bos) || dec.ttl || dec.tc)
			return -EINVAL;

649
		switch (dec.label) {
650
		case MPLS_LABEL_IMPLNULL:
651 652 653 654 655 656 657
			/* RFC3032: This is a label that an LSR may
			 * assign and distribute, but which never
			 * actually appears in the encapsulation.
			 */
			return -EINVAL;
		}

658 659 660 661 662 663
		label[i] = dec.label;
	}
	*labels = nla_labels;
	return 0;
}

664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
			       struct mpls_route_config *cfg)
{
	struct rtmsg *rtm;
	struct nlattr *tb[RTA_MAX+1];
	int index;
	int err;

	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_mpls_policy);
	if (err < 0)
		goto errout;

	err = -EINVAL;
	rtm = nlmsg_data(nlh);
	memset(cfg, 0, sizeof(*cfg));

	if (rtm->rtm_family != AF_MPLS)
		goto errout;
	if (rtm->rtm_dst_len != 20)
		goto errout;
	if (rtm->rtm_src_len != 0)
		goto errout;
	if (rtm->rtm_tos != 0)
		goto errout;
	if (rtm->rtm_table != RT_TABLE_MAIN)
		goto errout;
	/* Any value is acceptable for rtm_protocol */

	/* As mpls uses destination specific addresses
	 * (or source specific address in the case of multicast)
	 * all addresses have universal scope.
	 */
	if (rtm->rtm_scope != RT_SCOPE_UNIVERSE)
		goto errout;
	if (rtm->rtm_type != RTN_UNICAST)
		goto errout;
	if (rtm->rtm_flags != 0)
		goto errout;

	cfg->rc_label		= LABEL_NOT_SPECIFIED;
	cfg->rc_protocol	= rtm->rtm_protocol;
	cfg->rc_nlflags		= nlh->nlmsg_flags;
	cfg->rc_nlinfo.portid	= NETLINK_CB(skb).portid;
	cfg->rc_nlinfo.nlh	= nlh;
	cfg->rc_nlinfo.nl_net	= sock_net(skb->sk);

	for (index = 0; index <= RTA_MAX; index++) {
		struct nlattr *nla = tb[index];
		if (!nla)
			continue;

		switch(index) {
		case RTA_OIF:
			cfg->rc_ifindex = nla_get_u32(nla);
			break;
		case RTA_NEWDST:
			if (nla_get_labels(nla, MAX_NEW_LABELS,
					   &cfg->rc_output_labels,
					   cfg->rc_output_label))
				goto errout;
			break;
		case RTA_DST:
		{
			u32 label_count;
			if (nla_get_labels(nla, 1, &label_count,
					   &cfg->rc_label))
				goto errout;

			/* The first 16 labels are reserved, and may not be set */
			if (cfg->rc_label < 16)
				goto errout;

			break;
		}
		case RTA_VIA:
		{
			struct rtvia *via = nla_data(nla);
741 742 743 744
			if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
				goto errout;
			cfg->rc_via_alen   = nla_len(nla) -
				offsetof(struct rtvia, rtvia_addr);
745 746 747 748
			if (cfg->rc_via_alen > MAX_VIA_ALEN)
				goto errout;

			/* Validate the address family */
749
			switch(via->rtvia_family) {
750
			case AF_PACKET:
751
				cfg->rc_via_table = NEIGH_LINK_TABLE;
752 753
				break;
			case AF_INET:
754
				cfg->rc_via_table = NEIGH_ARP_TABLE;
755 756 757 758
				if (cfg->rc_via_alen != 4)
					goto errout;
				break;
			case AF_INET6:
759
				cfg->rc_via_table = NEIGH_ND_TABLE;
760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809
				if (cfg->rc_via_alen != 16)
					goto errout;
				break;
			default:
				/* Unsupported address family */
				goto errout;
			}

			memcpy(cfg->rc_via, via->rtvia_addr, cfg->rc_via_alen);
			break;
		}
		default:
			/* Unsupported attribute */
			goto errout;
		}
	}

	err = 0;
errout:
	return err;
}

static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	struct mpls_route_config cfg;
	int err;

	err = rtm_to_route_config(skb, nlh, &cfg);
	if (err < 0)
		return err;

	return mpls_route_del(&cfg);
}


static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	struct mpls_route_config cfg;
	int err;

	err = rtm_to_route_config(skb, nlh, &cfg);
	if (err < 0)
		return err;

	return mpls_route_add(&cfg);
}

static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
			   u32 label, struct mpls_route *rt, int flags)
{
810
	struct net_device *dev;
811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831
	struct nlmsghdr *nlh;
	struct rtmsg *rtm;

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

	rtm = nlmsg_data(nlh);
	rtm->rtm_family = AF_MPLS;
	rtm->rtm_dst_len = 20;
	rtm->rtm_src_len = 0;
	rtm->rtm_tos = 0;
	rtm->rtm_table = RT_TABLE_MAIN;
	rtm->rtm_protocol = rt->rt_protocol;
	rtm->rtm_scope = RT_SCOPE_UNIVERSE;
	rtm->rtm_type = RTN_UNICAST;
	rtm->rtm_flags = 0;

	if (rt->rt_labels &&
	    nla_put_labels(skb, RTA_NEWDST, rt->rt_labels, rt->rt_label))
		goto nla_put_failure;
832
	if (nla_put_via(skb, rt->rt_via_table, rt->rt_via, rt->rt_via_alen))
833
		goto nla_put_failure;
834 835
	dev = rtnl_dereference(rt->rt_dev);
	if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
836 837 838 839 840 841 842 843 844 845 846 847 848 849 850
		goto nla_put_failure;
	if (nla_put_labels(skb, RTA_DST, 1, &label))
		goto nla_put_failure;

	nlmsg_end(skb, nlh);
	return 0;

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

static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct net *net = sock_net(skb->sk);
851 852
	struct mpls_route __rcu **platform_label;
	size_t platform_labels;
853 854 855 856 857 858 859 860
	unsigned int index;

	ASSERT_RTNL();

	index = cb->args[0];
	if (index < 16)
		index = 16;

861 862 863
	platform_label = rtnl_dereference(net->mpls.platform_label);
	platform_labels = net->mpls.platform_labels;
	for (; index < platform_labels; index++) {
864
		struct mpls_route *rt;
865
		rt = rtnl_dereference(platform_label[index]);
866 867 868 869 870 871 872 873 874 875 876 877 878
		if (!rt)
			continue;

		if (mpls_dump_route(skb, NETLINK_CB(cb->skb).portid,
				    cb->nlh->nlmsg_seq, RTM_NEWROUTE,
				    index, rt, NLM_F_MULTI) < 0)
			break;
	}
	cb->args[0] = index;

	return skb->len;
}

879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918
static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
{
	size_t payload =
		NLMSG_ALIGN(sizeof(struct rtmsg))
		+ nla_total_size(2 + rt->rt_via_alen)	/* RTA_VIA */
		+ nla_total_size(4);			/* RTA_DST */
	if (rt->rt_labels)				/* RTA_NEWDST */
		payload += nla_total_size(rt->rt_labels * 4);
	if (rt->rt_dev)					/* RTA_OIF */
		payload += nla_total_size(4);
	return payload;
}

static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt,
		       struct nlmsghdr *nlh, struct net *net, u32 portid,
		       unsigned int nlm_flags)
{
	struct sk_buff *skb;
	u32 seq = nlh ? nlh->nlmsg_seq : 0;
	int err = -ENOBUFS;

	skb = nlmsg_new(lfib_nlmsg_size(rt), GFP_KERNEL);
	if (skb == NULL)
		goto errout;

	err = mpls_dump_route(skb, portid, seq, event, label, rt, nlm_flags);
	if (err < 0) {
		/* -EMSGSIZE implies BUG in lfib_nlmsg_size */
		WARN_ON(err == -EMSGSIZE);
		kfree_skb(skb);
		goto errout;
	}
	rtnl_notify(skb, net, portid, RTNLGRP_MPLS_ROUTE, nlh, GFP_KERNEL);

	return;
errout:
	if (err < 0)
		rtnl_set_sk_err(net, RTNLGRP_MPLS_ROUTE, err);
}

919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937
static int resize_platform_label_table(struct net *net, size_t limit)
{
	size_t size = sizeof(struct mpls_route *) * limit;
	size_t old_limit;
	size_t cp_size;
	struct mpls_route __rcu **labels = NULL, **old;
	struct mpls_route *rt0 = NULL, *rt2 = NULL;
	unsigned index;

	if (size) {
		labels = kzalloc(size, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
		if (!labels)
			labels = vzalloc(size);

		if (!labels)
			goto nolabels;
	}

	/* In case the predefined labels need to be populated */
938
	if (limit > MPLS_LABEL_IPV4NULL) {
939 940 941 942
		struct net_device *lo = net->loopback_dev;
		rt0 = mpls_rt_alloc(lo->addr_len);
		if (!rt0)
			goto nort0;
943
		RCU_INIT_POINTER(rt0->rt_dev, lo);
944
		rt0->rt_protocol = RTPROT_KERNEL;
945
		rt0->rt_via_table = NEIGH_LINK_TABLE;
946 947
		memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
	}
948
	if (limit > MPLS_LABEL_IPV6NULL) {
949 950 951 952
		struct net_device *lo = net->loopback_dev;
		rt2 = mpls_rt_alloc(lo->addr_len);
		if (!rt2)
			goto nort2;
953
		RCU_INIT_POINTER(rt2->rt_dev, lo);
954
		rt2->rt_protocol = RTPROT_KERNEL;
955
		rt2->rt_via_table = NEIGH_LINK_TABLE;
956 957 958 959 960
		memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len);
	}

	rtnl_lock();
	/* Remember the original table */
961
	old = rtnl_dereference(net->mpls.platform_label);
962 963 964 965 966 967 968 969 970 971 972 973 974 975
	old_limit = net->mpls.platform_labels;

	/* Free any labels beyond the new table */
	for (index = limit; index < old_limit; index++)
		mpls_route_update(net, index, NULL, NULL, NULL);

	/* Copy over the old labels */
	cp_size = size;
	if (old_limit < limit)
		cp_size = old_limit * sizeof(struct mpls_route *);

	memcpy(labels, old, cp_size);

	/* If needed set the predefined labels */
976 977 978
	if ((old_limit <= MPLS_LABEL_IPV6NULL) &&
	    (limit > MPLS_LABEL_IPV6NULL)) {
		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6NULL], rt2);
979 980 981
		rt2 = NULL;
	}

982 983 984
	if ((old_limit <= MPLS_LABEL_IPV4NULL) &&
	    (limit > MPLS_LABEL_IPV4NULL)) {
		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4NULL], rt0);
985 986 987 988 989
		rt0 = NULL;
	}

	/* Update the global pointers */
	net->mpls.platform_labels = limit;
990
	rcu_assign_pointer(net->mpls.platform_label, labels);
991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033

	rtnl_unlock();

	mpls_rt_free(rt2);
	mpls_rt_free(rt0);

	if (old) {
		synchronize_rcu();
		kvfree(old);
	}
	return 0;

nort2:
	mpls_rt_free(rt0);
nort0:
	kvfree(labels);
nolabels:
	return -ENOMEM;
}

static int mpls_platform_labels(struct ctl_table *table, int write,
				void __user *buffer, size_t *lenp, loff_t *ppos)
{
	struct net *net = table->data;
	int platform_labels = net->mpls.platform_labels;
	int ret;
	struct ctl_table tmp = {
		.procname	= table->procname,
		.data		= &platform_labels,
		.maxlen		= sizeof(int),
		.mode		= table->mode,
		.extra1		= &zero,
		.extra2		= &label_limit,
	};

	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);

	if (write && ret == 0)
		ret = resize_platform_label_table(net, platform_labels);

	return ret;
}

1034
static const struct ctl_table mpls_table[] = {
1035 1036 1037 1038 1039 1040 1041 1042 1043 1044
	{
		.procname	= "platform_labels",
		.data		= NULL,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= mpls_platform_labels,
	},
	{ }
};

E
Eric W. Biederman 已提交
1045 1046
static int mpls_net_init(struct net *net)
{
1047 1048
	struct ctl_table *table;

E
Eric W. Biederman 已提交
1049 1050 1051
	net->mpls.platform_labels = 0;
	net->mpls.platform_label = NULL;

1052 1053 1054 1055 1056 1057 1058 1059 1060
	table = kmemdup(mpls_table, sizeof(mpls_table), GFP_KERNEL);
	if (table == NULL)
		return -ENOMEM;

	table[0].data = net;
	net->mpls.ctl = register_net_sysctl(net, "net/mpls", table);
	if (net->mpls.ctl == NULL)
		return -ENOMEM;

E
Eric W. Biederman 已提交
1061 1062 1063 1064 1065
	return 0;
}

static void mpls_net_exit(struct net *net)
{
1066 1067
	struct mpls_route __rcu **platform_label;
	size_t platform_labels;
1068
	struct ctl_table *table;
E
Eric W. Biederman 已提交
1069 1070
	unsigned int index;

1071 1072 1073 1074
	table = net->mpls.ctl->ctl_table_arg;
	unregister_net_sysctl_table(net->mpls.ctl);
	kfree(table);

1075 1076
	/* An rcu grace period has passed since there was a device in
	 * the network namespace (and thus the last in flight packet)
E
Eric W. Biederman 已提交
1077 1078 1079 1080 1081 1082 1083 1084
	 * left this network namespace.  This is because
	 * unregister_netdevice_many and netdev_run_todo has completed
	 * for each network device that was in this network namespace.
	 *
	 * As such no additional rcu synchronization is necessary when
	 * freeing the platform_label table.
	 */
	rtnl_lock();
1085 1086 1087 1088 1089
	platform_label = rtnl_dereference(net->mpls.platform_label);
	platform_labels = net->mpls.platform_labels;
	for (index = 0; index < platform_labels; index++) {
		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
		RCU_INIT_POINTER(platform_label[index], NULL);
E
Eric W. Biederman 已提交
1090 1091 1092 1093
		mpls_rt_free(rt);
	}
	rtnl_unlock();

1094
	kvfree(platform_label);
E
Eric W. Biederman 已提交
1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117
}

static struct pernet_operations mpls_net_ops = {
	.init = mpls_net_init,
	.exit = mpls_net_exit,
};

static int __init mpls_init(void)
{
	int err;

	BUILD_BUG_ON(sizeof(struct mpls_shim_hdr) != 4);

	err = register_pernet_subsys(&mpls_net_ops);
	if (err)
		goto out;

	err = register_netdevice_notifier(&mpls_dev_notifier);
	if (err)
		goto out_unregister_pernet;

	dev_add_pack(&mpls_packet_type);

1118 1119 1120
	rtnl_register(PF_MPLS, RTM_NEWROUTE, mpls_rtm_newroute, NULL, NULL);
	rtnl_register(PF_MPLS, RTM_DELROUTE, mpls_rtm_delroute, NULL, NULL);
	rtnl_register(PF_MPLS, RTM_GETROUTE, NULL, mpls_dump_routes, NULL);
E
Eric W. Biederman 已提交
1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132
	err = 0;
out:
	return err;

out_unregister_pernet:
	unregister_pernet_subsys(&mpls_net_ops);
	goto out;
}
module_init(mpls_init);

static void __exit mpls_exit(void)
{
1133
	rtnl_unregister_all(PF_MPLS);
E
Eric W. Biederman 已提交
1134 1135 1136 1137 1138 1139 1140 1141 1142
	dev_remove_pack(&mpls_packet_type);
	unregister_netdevice_notifier(&mpls_dev_notifier);
	unregister_pernet_subsys(&mpls_net_ops);
}
module_exit(mpls_exit);

MODULE_DESCRIPTION("MultiProtocol Label Switching");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_NETPROTO(PF_MPLS);