af_mpls.c 28.8 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>
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#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
#include <net/addrconf.h>
#endif
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#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)))

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enum mpls_payload_type {
	MPT_UNSPEC, /* IPv4 or IPv6 */
	MPT_IPV4 = 4,
	MPT_IPV6 = 6,

	/* Other types not implemented:
	 *  - Pseudo-wire with or without control word (RFC4385)
	 *  - GAL (RFC5586)
	 */
};

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

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unsigned int mpls_dev_mtu(const struct net_device *dev)
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{
	/* The amount of data the layer 2 frame can hold */
	return dev->mtu;
}
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EXPORT_SYMBOL_GPL(mpls_dev_mtu);
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bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
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{
	if (skb->len <= mtu)
		return false;

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

	return true;
}
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EXPORT_SYMBOL_GPL(mpls_pkt_too_big);
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static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb,
			struct mpls_entry_decoded dec)
{
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	enum mpls_payload_type payload_type;
	bool success = false;
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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;

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	payload_type = rt->rt_payload_type;
	if (payload_type == MPT_UNSPEC)
		payload_type = ip_hdr(skb)->version;

	switch (payload_type) {
	case MPT_IPV4: {
		struct iphdr *hdr4 = ip_hdr(skb);
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		skb->protocol = htons(ETH_P_IP);
		csum_replace2(&hdr4->check,
			      htons(hdr4->ttl << 8),
			      htons(dec.ttl << 8));
		hdr4->ttl = dec.ttl;
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		success = true;
		break;
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	}
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	case MPT_IPV6: {
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		struct ipv6hdr *hdr6 = ipv6_hdr(skb);
		skb->protocol = htons(ETH_P_IPV6);
		hdr6->hop_limit = dec.ttl;
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		success = true;
		break;
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	}
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	case MPT_UNSPEC:
		break;
	}

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	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 {
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	u32			rc_protocol;
	u32			rc_ifindex;
	u16			rc_via_table;
	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;
	enum mpls_payload_type	rc_payload_type;
	struct nl_info		rc_nlinfo;
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};

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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 */
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	if (rt && (index >= MPLS_LABEL_FIRST_UNRESERVED))
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		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;
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	for (index = MPLS_LABEL_FIRST_UNRESERVED; index < platform_labels;
	     index++) {
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		if (!rtnl_dereference(platform_label[index]))
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			return index;
	}
	return LABEL_NOT_SPECIFIED;
}

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#if IS_ENABLED(CONFIG_INET)
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static struct net_device *inet_fib_lookup_dev(struct net *net, void *addr)
{
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	struct net_device *dev;
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	struct rtable *rt;
	struct in_addr daddr;

	memcpy(&daddr, addr, sizeof(struct in_addr));
	rt = ip_route_output(net, daddr.s_addr, 0, 0, 0);
	if (IS_ERR(rt))
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		return ERR_CAST(rt);
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	dev = rt->dst.dev;
	dev_hold(dev);

	ip_rt_put(rt);

	return dev;
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}
#else
static struct net_device *inet_fib_lookup_dev(struct net *net, void *addr)
{
	return ERR_PTR(-EAFNOSUPPORT);
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}
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#endif
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#if IS_ENABLED(CONFIG_IPV6)
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static struct net_device *inet6_fib_lookup_dev(struct net *net, void *addr)
{
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	struct net_device *dev;
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	struct dst_entry *dst;
	struct flowi6 fl6;
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	int err;

	if (!ipv6_stub)
		return ERR_PTR(-EAFNOSUPPORT);
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	memset(&fl6, 0, sizeof(fl6));
	memcpy(&fl6.daddr, addr, sizeof(struct in6_addr));
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	err = ipv6_stub->ipv6_dst_lookup(net, NULL, &dst, &fl6);
	if (err)
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		return ERR_PTR(err);
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	dev = dst->dev;
	dev_hold(dev);
	dst_release(dst);

	return dev;
}
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#else
static struct net_device *inet6_fib_lookup_dev(struct net *net, void *addr)
{
	return ERR_PTR(-EAFNOSUPPORT);
}
#endif
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static struct net_device *find_outdev(struct net *net,
				      struct mpls_route_config *cfg)
{
	struct net_device *dev = NULL;

	if (!cfg->rc_ifindex) {
		switch (cfg->rc_via_table) {
		case NEIGH_ARP_TABLE:
			dev = inet_fib_lookup_dev(net, cfg->rc_via);
			break;
		case NEIGH_ND_TABLE:
			dev = inet6_fib_lookup_dev(net, cfg->rc_via);
			break;
		case NEIGH_LINK_TABLE:
			break;
		}
	} else {
		dev = dev_get_by_index(net, cfg->rc_ifindex);
	}

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	if (!dev)
		return ERR_PTR(-ENODEV);

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	return dev;
}

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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);
	}

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	/* Reserved labels may not be set */
	if (index < MPLS_LABEL_FIRST_UNRESERVED)
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		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;

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	dev = find_outdev(net, cfg);
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	if (IS_ERR(dev)) {
		err = PTR_ERR(dev);
		dev = NULL;
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		goto errout;
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	}
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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_payload_type = cfg->rc_payload_type;
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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;

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	/* Reserved labels may not be removed */
	if (index < MPLS_LABEL_FIRST_UNRESERVED)
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		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)
{
628
	struct mpls_route __rcu **platform_label;
E
Eric W. Biederman 已提交
629
	struct net *net = dev_net(dev);
R
Robert Shearman 已提交
630
	struct mpls_dev *mdev;
E
Eric W. Biederman 已提交
631 632
	unsigned index;

633
	platform_label = rtnl_dereference(net->mpls.platform_label);
E
Eric W. Biederman 已提交
634
	for (index = 0; index < net->mpls.platform_labels; index++) {
635
		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
E
Eric W. Biederman 已提交
636 637
		if (!rt)
			continue;
638
		if (rtnl_dereference(rt->rt_dev) != dev)
E
Eric W. Biederman 已提交
639 640 641
			continue;
		rt->rt_dev = NULL;
	}
R
Robert Shearman 已提交
642 643 644 645 646

	mdev = mpls_dev_get(dev);
	if (!mdev)
		return;

647 648
	mpls_dev_sysctl_unregister(mdev);

R
Robert Shearman 已提交
649 650
	RCU_INIT_POINTER(dev->mpls_ptr, NULL);

651
	kfree_rcu(mdev, rcu);
E
Eric W. Biederman 已提交
652 653 654 655 656 657
}

static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
			   void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
R
Robert Shearman 已提交
658
	struct mpls_dev *mdev;
E
Eric W. Biederman 已提交
659 660

	switch(event) {
R
Robert Shearman 已提交
661 662 663 664 665 666 667 668 669 670
	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;

E
Eric W. Biederman 已提交
671 672 673
	case NETDEV_UNREGISTER:
		mpls_ifdown(dev);
		break;
674 675 676 677 678 679 680 681 682 683 684
	case NETDEV_CHANGENAME:
		mdev = mpls_dev_get(dev);
		if (mdev) {
			int err;

			mpls_dev_sysctl_unregister(mdev);
			err = mpls_dev_sysctl_register(dev, mdev);
			if (err)
				return notifier_from_errno(err);
		}
		break;
E
Eric W. Biederman 已提交
685 686 687 688 689 690 691 692
	}
	return NOTIFY_OK;
}

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

693
static int nla_put_via(struct sk_buff *skb,
694
		       u8 table, const void *addr, int alen)
695
{
696 697 698
	static const int table_to_family[NEIGH_NR_TABLES + 1] = {
		AF_INET, AF_INET6, AF_DECnet, AF_PACKET,
	};
699 700
	struct nlattr *nla;
	struct rtvia *via;
701
	int family = AF_UNSPEC;
702 703 704 705 706

	nla = nla_reserve(skb, RTA_VIA, alen + 2);
	if (!nla)
		return -EMSGSIZE;

707 708 709
	if (table <= NEIGH_NR_TABLES)
		family = table_to_family[table];

710 711 712 713 714 715
	via = nla_data(nla);
	via->rtvia_family = family;
	memcpy(via->rtvia_addr, addr, alen);
	return 0;
}

716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735
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;
}
736
EXPORT_SYMBOL_GPL(nla_put_labels);
737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767

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;

768
		switch (dec.label) {
769
		case MPLS_LABEL_IMPLNULL:
770 771 772 773 774 775 776
			/* RFC3032: This is a label that an LSR may
			 * assign and distribute, but which never
			 * actually appears in the encapsulation.
			 */
			return -EINVAL;
		}

777 778 779 780 781
		label[i] = dec.label;
	}
	*labels = nla_labels;
	return 0;
}
782
EXPORT_SYMBOL_GPL(nla_get_labels);
783

784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851
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;

852 853
			/* Reserved labels may not be set */
			if (cfg->rc_label < MPLS_LABEL_FIRST_UNRESERVED)
854 855 856 857 858 859 860
				goto errout;

			break;
		}
		case RTA_VIA:
		{
			struct rtvia *via = nla_data(nla);
861 862 863 864
			if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
				goto errout;
			cfg->rc_via_alen   = nla_len(nla) -
				offsetof(struct rtvia, rtvia_addr);
865 866 867 868
			if (cfg->rc_via_alen > MAX_VIA_ALEN)
				goto errout;

			/* Validate the address family */
869
			switch(via->rtvia_family) {
870
			case AF_PACKET:
871
				cfg->rc_via_table = NEIGH_LINK_TABLE;
872 873
				break;
			case AF_INET:
874
				cfg->rc_via_table = NEIGH_ARP_TABLE;
875 876 877 878
				if (cfg->rc_via_alen != 4)
					goto errout;
				break;
			case AF_INET6:
879
				cfg->rc_via_table = NEIGH_ND_TABLE;
880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929
				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)
{
930
	struct net_device *dev;
931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951
	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;
952
	if (nla_put_via(skb, rt->rt_via_table, rt->rt_via, rt->rt_via_alen))
953
		goto nla_put_failure;
954 955
	dev = rtnl_dereference(rt->rt_dev);
	if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
956 957 958 959 960 961 962 963 964 965 966 967 968 969 970
		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);
971 972
	struct mpls_route __rcu **platform_label;
	size_t platform_labels;
973 974 975 976 977
	unsigned int index;

	ASSERT_RTNL();

	index = cb->args[0];
978 979
	if (index < MPLS_LABEL_FIRST_UNRESERVED)
		index = MPLS_LABEL_FIRST_UNRESERVED;
980

981 982 983
	platform_label = rtnl_dereference(net->mpls.platform_label);
	platform_labels = net->mpls.platform_labels;
	for (; index < platform_labels; index++) {
984
		struct mpls_route *rt;
985
		rt = rtnl_dereference(platform_label[index]);
986 987 988 989 990 991 992 993 994 995 996 997 998
		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;
}

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 1034 1035 1036 1037 1038
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);
}

1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057
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 */
1058
	if (limit > MPLS_LABEL_IPV4NULL) {
1059 1060 1061 1062
		struct net_device *lo = net->loopback_dev;
		rt0 = mpls_rt_alloc(lo->addr_len);
		if (!rt0)
			goto nort0;
1063
		RCU_INIT_POINTER(rt0->rt_dev, lo);
1064
		rt0->rt_protocol = RTPROT_KERNEL;
1065
		rt0->rt_payload_type = MPT_IPV4;
1066
		rt0->rt_via_table = NEIGH_LINK_TABLE;
1067 1068
		memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
	}
1069
	if (limit > MPLS_LABEL_IPV6NULL) {
1070 1071 1072 1073
		struct net_device *lo = net->loopback_dev;
		rt2 = mpls_rt_alloc(lo->addr_len);
		if (!rt2)
			goto nort2;
1074
		RCU_INIT_POINTER(rt2->rt_dev, lo);
1075
		rt2->rt_protocol = RTPROT_KERNEL;
1076
		rt2->rt_payload_type = MPT_IPV6;
1077
		rt2->rt_via_table = NEIGH_LINK_TABLE;
1078 1079 1080 1081 1082
		memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len);
	}

	rtnl_lock();
	/* Remember the original table */
1083
	old = rtnl_dereference(net->mpls.platform_label);
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097
	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 */
1098 1099 1100
	if ((old_limit <= MPLS_LABEL_IPV6NULL) &&
	    (limit > MPLS_LABEL_IPV6NULL)) {
		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6NULL], rt2);
1101 1102 1103
		rt2 = NULL;
	}

1104 1105 1106
	if ((old_limit <= MPLS_LABEL_IPV4NULL) &&
	    (limit > MPLS_LABEL_IPV4NULL)) {
		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4NULL], rt0);
1107 1108 1109 1110 1111
		rt0 = NULL;
	}

	/* Update the global pointers */
	net->mpls.platform_labels = limit;
1112
	rcu_assign_pointer(net->mpls.platform_label, labels);
1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155

	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;
}

1156
static const struct ctl_table mpls_table[] = {
1157 1158 1159 1160 1161 1162 1163 1164 1165 1166
	{
		.procname	= "platform_labels",
		.data		= NULL,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= mpls_platform_labels,
	},
	{ }
};

E
Eric W. Biederman 已提交
1167 1168
static int mpls_net_init(struct net *net)
{
1169 1170
	struct ctl_table *table;

E
Eric W. Biederman 已提交
1171 1172 1173
	net->mpls.platform_labels = 0;
	net->mpls.platform_label = NULL;

1174 1175 1176 1177 1178 1179 1180 1181 1182
	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
1183 1184 1185 1186 1187
	return 0;
}

static void mpls_net_exit(struct net *net)
{
1188 1189
	struct mpls_route __rcu **platform_label;
	size_t platform_labels;
1190
	struct ctl_table *table;
E
Eric W. Biederman 已提交
1191 1192
	unsigned int index;

1193 1194 1195 1196
	table = net->mpls.ctl->ctl_table_arg;
	unregister_net_sysctl_table(net->mpls.ctl);
	kfree(table);

1197 1198
	/* 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
1199 1200 1201 1202 1203 1204 1205 1206
	 * 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();
1207 1208 1209 1210 1211
	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
1212 1213 1214 1215
		mpls_rt_free(rt);
	}
	rtnl_unlock();

1216
	kvfree(platform_label);
E
Eric W. Biederman 已提交
1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239
}

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);

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	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
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	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)
{
1255
	rtnl_unregister_all(PF_MPLS);
E
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	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);