af_mpls.c 23.3 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 */
	u8			rt_labels:2,
				rt_via_alen:6;
	unsigned short		rt_via_family;
	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;
}

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.
	 */
	struct iphdr *hdr4 = ip_hdr(skb);
	bool success = true;

	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;
	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 */

	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 */
	if (dec.ttl <= 2)
		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;
		}
	}

	err = neigh_xmit(rt->rt_via_family, out_dev, rt->rt_via, skb);
	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;
	u16		rc_via_family;
	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;

	/* For now just support ethernet devices */
	err = -EINVAL;
	if ((dev->type != ARPHRD_ETHER) && (dev->type != ARPHRD_LOOPBACK))
		goto errout;

	err = -EINVAL;
	if ((cfg->rc_via_family == AF_PACKET) &&
	    (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_family = cfg->rc_via_family;
	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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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);
	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;
	}
}

static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
			   void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);

	switch(event) {
	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,
		       u16 family, const void *addr, int alen)
{
	struct nlattr *nla;
	struct rtvia *via;

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

	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;

		label[i] = dec.label;
	}
	*labels = nla_labels;
	return 0;
}

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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);
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			if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
				goto errout;
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			cfg->rc_via_family = via->rtvia_family;
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			cfg->rc_via_alen   = nla_len(nla) -
				offsetof(struct rtvia, rtvia_addr);
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			if (cfg->rc_via_alen > MAX_VIA_ALEN)
				goto errout;

			/* Validate the address family */
			switch(cfg->rc_via_family) {
			case AF_PACKET:
				break;
			case AF_INET:
				if (cfg->rc_via_alen != 4)
					goto errout;
				break;
			case AF_INET6:
				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)
{
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	struct net_device *dev;
668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690
	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;
	if (nla_put_via(skb, rt->rt_via_family, rt->rt_via, rt->rt_via_alen))
		goto nla_put_failure;
691 692
	dev = rtnl_dereference(rt->rt_dev);
	if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
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		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);
708 709
	struct mpls_route __rcu **platform_label;
	size_t platform_labels;
710 711 712 713 714 715 716 717
	unsigned int index;

	ASSERT_RTNL();

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

718 719 720
	platform_label = rtnl_dereference(net->mpls.platform_label);
	platform_labels = net->mpls.platform_labels;
	for (; index < platform_labels; index++) {
721
		struct mpls_route *rt;
722
		rt = rtnl_dereference(platform_label[index]);
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		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;
}

736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775
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);
}

776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799
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 */
	if (limit > LABEL_IPV4_EXPLICIT_NULL) {
		struct net_device *lo = net->loopback_dev;
		rt0 = mpls_rt_alloc(lo->addr_len);
		if (!rt0)
			goto nort0;
800
		RCU_INIT_POINTER(rt0->rt_dev, lo);
801 802 803 804 805 806 807 808 809
		rt0->rt_protocol = RTPROT_KERNEL;
		rt0->rt_via_family = AF_PACKET;
		memcpy(rt0->rt_via, lo->dev_addr, lo->addr_len);
	}
	if (limit > LABEL_IPV6_EXPLICIT_NULL) {
		struct net_device *lo = net->loopback_dev;
		rt2 = mpls_rt_alloc(lo->addr_len);
		if (!rt2)
			goto nort2;
810
		RCU_INIT_POINTER(rt2->rt_dev, lo);
811 812 813 814 815 816 817
		rt2->rt_protocol = RTPROT_KERNEL;
		rt2->rt_via_family = AF_PACKET;
		memcpy(rt2->rt_via, lo->dev_addr, lo->addr_len);
	}

	rtnl_lock();
	/* Remember the original table */
818
	old = rtnl_dereference(net->mpls.platform_label);
819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834
	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 */
	if ((old_limit <= LABEL_IPV6_EXPLICIT_NULL) &&
	    (limit > LABEL_IPV6_EXPLICIT_NULL)) {
835
		RCU_INIT_POINTER(labels[LABEL_IPV6_EXPLICIT_NULL], rt2);
836 837 838 839 840
		rt2 = NULL;
	}

	if ((old_limit <= LABEL_IPV4_EXPLICIT_NULL) &&
	    (limit > LABEL_IPV4_EXPLICIT_NULL)) {
841
		RCU_INIT_POINTER(labels[LABEL_IPV4_EXPLICIT_NULL], rt0);
842 843 844 845 846
		rt0 = NULL;
	}

	/* Update the global pointers */
	net->mpls.platform_labels = limit;
847
	rcu_assign_pointer(net->mpls.platform_label, labels);
848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901

	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;
}

static struct ctl_table mpls_table[] = {
	{
		.procname	= "platform_labels",
		.data		= NULL,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= mpls_platform_labels,
	},
	{ }
};

E
Eric W. Biederman 已提交
902 903
static int mpls_net_init(struct net *net)
{
904 905
	struct ctl_table *table;

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

909 910 911 912 913 914 915 916 917
	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
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	return 0;
}

static void mpls_net_exit(struct net *net)
{
923 924
	struct mpls_route __rcu **platform_label;
	size_t platform_labels;
925
	struct ctl_table *table;
E
Eric W. Biederman 已提交
926 927
	unsigned int index;

928 929 930 931
	table = net->mpls.ctl->ctl_table_arg;
	unregister_net_sysctl_table(net->mpls.ctl);
	kfree(table);

932 933
	/* 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
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	 * 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();
942 943 944 945 946
	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
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		mpls_rt_free(rt);
	}
	rtnl_unlock();

951
	kvfree(platform_label);
E
Eric W. Biederman 已提交
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}

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);

975 976 977
	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
978 979 980 981 982 983 984 985 986 987 988 989
	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)
{
990
	rtnl_unregister_all(PF_MPLS);
E
Eric W. Biederman 已提交
991 992 993 994 995 996 997 998 999
	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);