--- /dev/null
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <linux/socket.h>
+#include <linux/net.h>
+#include <linux/module.h>
+#include <linux/if_arp.h>
+#include <linux/ipv6.h>
+#include <linux/mpls.h>
+#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"
+
+#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 */
+ struct net_device *rt_dev;
+ 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];
+};
+
+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 */
+ out_dev = rt->rt_dev;
+ 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,
+};
+
+static struct mpls_route *mpls_rt_alloc(size_t alen)
+{
+ struct mpls_route *rt;
+
+ rt = kzalloc(GFP_KERNEL, sizeof(*rt) + alen);
+ 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);
+}
+
+static void mpls_route_update(struct net *net, unsigned index,
+ struct net_device *dev, struct mpls_route *new,
+ const struct nl_info *info)
+{
+ struct mpls_route *rt, *old = NULL;
+
+ ASSERT_RTNL();
+
+ rt = net->mpls.platform_label[index];
+ if (!dev || (rt && (rt->rt_dev == dev))) {
+ rcu_assign_pointer(net->mpls.platform_label[index], new);
+ old = rt;
+ }
+
+ /* If we removed a route free it now */
+ mpls_rt_free(old);
+}
+
+static void mpls_ifdown(struct net_device *dev)
+{
+ struct net *net = dev_net(dev);
+ unsigned index;
+
+ for (index = 0; index < net->mpls.platform_labels; index++) {
+ struct mpls_route *rt = net->mpls.platform_label[index];
+ if (!rt)
+ continue;
+ if (rt->rt_dev != dev)
+ 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,
+};
+
+static int mpls_net_init(struct net *net)
+{
+ net->mpls.platform_labels = 0;
+ net->mpls.platform_label = NULL;
+
+ return 0;
+}
+
+static void mpls_net_exit(struct net *net)
+{
+ unsigned int index;
+
+ /* An rcu grace period haselapsed since there was a device in
+ * the network namespace (and thus the last in fqlight packet)
+ * 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();
+ for (index = 0; index < net->mpls.platform_labels; index++) {
+ struct mpls_route *rt = net->mpls.platform_label[index];
+ rcu_assign_pointer(net->mpls.platform_label[index], NULL);
+ mpls_rt_free(rt);
+ }
+ rtnl_unlock();
+
+ kvfree(net->mpls.platform_label);
+}
+
+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);
+
+ 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)
+{
+ 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);
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff