diff options
Diffstat (limited to 'net/mpls/af_mpls.c')
| -rw-r--r-- | net/mpls/af_mpls.c | 1628 |
1 files changed, 1628 insertions, 0 deletions
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c new file mode 100644 index 000000000000..50d9138b2a1c --- /dev/null +++ b/net/mpls/af_mpls.c @@ -0,0 +1,1628 @@ +#include <linux/types.h> +#include <linux/skbuff.h> +#include <linux/socket.h> +#include <linux/sysctl.h> +#include <linux/net.h> +#include <linux/module.h> +#include <linux/if_arp.h> +#include <linux/ipv6.h> +#include <linux/mpls.h> +#include <linux/nospec.h> +#include <linux/vmalloc.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> +#if IS_ENABLED(CONFIG_IPV6) +#include <net/ipv6.h> +#include <net/addrconf.h> +#endif +#include <net/nexthop.h> +#include "internal.h" + +/* Maximum number of labels to look ahead at when selecting a path of + * a multipath route + */ +#define MAX_MP_SELECT_LABELS 4 + +#define MPLS_NEIGH_TABLE_UNSPEC (NEIGH_LINK_TABLE + 1) + +static int zero = 0; +static int label_limit = (1 << 20) - 1; + +static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt, + struct nlmsghdr *nlh, struct net *net, u32 portid, + unsigned int nlm_flags); + +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 inline struct mpls_dev *mpls_dev_get(const struct net_device *dev) +{ + return rcu_dereference_rtnl(dev->mpls_ptr); +} + +bool mpls_output_possible(const struct net_device *dev) +{ + return dev && (dev->flags & IFF_UP) && netif_carrier_ok(dev); +} +EXPORT_SYMBOL_GPL(mpls_output_possible); + +static u8 *__mpls_nh_via(struct mpls_route *rt, struct mpls_nh *nh) +{ + u8 *nh0_via = PTR_ALIGN((u8 *)&rt->rt_nh[rt->rt_nhn], VIA_ALEN_ALIGN); + int nh_index = nh - rt->rt_nh; + + return nh0_via + rt->rt_max_alen * nh_index; +} + +static const u8 *mpls_nh_via(const struct mpls_route *rt, + const struct mpls_nh *nh) +{ + return __mpls_nh_via((struct mpls_route *)rt, (struct mpls_nh *)nh); +} + +static unsigned int mpls_nh_header_size(const struct mpls_nh *nh) +{ + /* The size of the layer 2.5 labels to be added for this route */ + return nh->nh_labels * sizeof(struct mpls_shim_hdr); +} + +unsigned int mpls_dev_mtu(const struct net_device *dev) +{ + /* The amount of data the layer 2 frame can hold */ + return dev->mtu; +} +EXPORT_SYMBOL_GPL(mpls_dev_mtu); + +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; +} +EXPORT_SYMBOL_GPL(mpls_pkt_too_big); + +static struct mpls_nh *mpls_select_multipath(struct mpls_route *rt, + struct sk_buff *skb, bool bos) +{ + struct mpls_entry_decoded dec; + struct mpls_shim_hdr *hdr; + bool eli_seen = false; + int label_index; + int nh_index = 0; + u32 hash = 0; + + /* No need to look further into packet if there's only + * one path + */ + if (rt->rt_nhn == 1) + goto out; + + for (label_index = 0; label_index < MAX_MP_SELECT_LABELS && !bos; + label_index++) { + if (!pskb_may_pull(skb, sizeof(*hdr) * label_index)) + break; + + /* Read and decode the current label */ + hdr = mpls_hdr(skb) + label_index; + dec = mpls_entry_decode(hdr); + + /* RFC6790 - reserved labels MUST NOT be used as keys + * for the load-balancing function + */ + if (likely(dec.label >= MPLS_LABEL_FIRST_UNRESERVED)) { + hash = jhash_1word(dec.label, hash); + + /* The entropy label follows the entropy label + * indicator, so this means that the entropy + * label was just added to the hash - no need to + * go any deeper either in the label stack or in the + * payload + */ + if (eli_seen) + break; + } else if (dec.label == MPLS_LABEL_ENTROPY) { + eli_seen = true; + } + + bos = dec.bos; + if (bos && pskb_may_pull(skb, sizeof(*hdr) * label_index + + sizeof(struct iphdr))) { + const struct iphdr *v4hdr; + + v4hdr = (const struct iphdr *)(mpls_hdr(skb) + + label_index); + if (v4hdr->version == 4) { + hash = jhash_3words(ntohl(v4hdr->saddr), + ntohl(v4hdr->daddr), + v4hdr->protocol, hash); + } else if (v4hdr->version == 6 && + pskb_may_pull(skb, sizeof(*hdr) * label_index + + sizeof(struct ipv6hdr))) { + const struct ipv6hdr *v6hdr; + + v6hdr = (const struct ipv6hdr *)(mpls_hdr(skb) + + label_index); + + hash = __ipv6_addr_jhash(&v6hdr->saddr, hash); + hash = __ipv6_addr_jhash(&v6hdr->daddr, hash); + hash = jhash_1word(v6hdr->nexthdr, hash); + } + } + } + + nh_index = hash % rt->rt_nhn; +out: + return &rt->rt_nh[nh_index]; +} + +static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb, + struct mpls_entry_decoded dec) +{ + enum mpls_payload_type payload_type; + bool success = false; + + /* 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; + + 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); + skb->protocol = htons(ETH_P_IP); + csum_replace2(&hdr4->check, + htons(hdr4->ttl << 8), + htons(dec.ttl << 8)); + hdr4->ttl = dec.ttl; + success = true; + break; + } + case MPT_IPV6: { + struct ipv6hdr *hdr6 = ipv6_hdr(skb); + skb->protocol = htons(ETH_P_IPV6); + hdr6->hop_limit = dec.ttl; + success = true; + break; + } + case MPT_UNSPEC: + break; + } + + 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_nh *nh; + struct mpls_entry_decoded dec; + struct net_device *out_dev; + struct mpls_dev *mdev; + 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 */ + + mdev = mpls_dev_get(dev); + if (!mdev || !mdev->input_enabled) + goto drop; + + 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; + + nh = mpls_select_multipath(rt, skb, dec.bos); + if (!nh) + goto drop; + + /* Find the output device */ + out_dev = rcu_dereference(nh->nh_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 <= 1) + goto drop; + dec.ttl -= 1; + + /* Verify the destination can hold the packet */ + new_header_size = mpls_nh_header_size(nh); + 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 = nh->nh_labels - 1; i >= 0; i--) { + hdr[i] = mpls_entry_encode(nh->nh_label[i], + dec.ttl, 0, bos); + bos = false; + } + } + + /* If via wasn't specified then send out using device address */ + if (nh->nh_via_table == MPLS_NEIGH_TABLE_UNSPEC) + err = neigh_xmit(NEIGH_LINK_TABLE, out_dev, + out_dev->dev_addr, skb); + else + err = neigh_xmit(nh->nh_via_table, out_dev, + mpls_nh_via(rt, nh), 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 const struct nla_policy rtm_mpls_policy[RTA_MAX+1] = { + [RTA_DST] = { .type = NLA_U32 }, + [RTA_OIF] = { .type = NLA_U32 }, +}; + +struct mpls_route_config { + u32 rc_protocol; + u32 rc_ifindex; + u8 rc_via_table; + u8 rc_via_alen; + u8 rc_via[MAX_VIA_ALEN]; + u32 rc_label; + u8 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; + struct rtnexthop *rc_mp; + int rc_mp_len; +}; + +static struct mpls_route *mpls_rt_alloc(int num_nh, u8 max_alen) +{ + u8 max_alen_aligned = ALIGN(max_alen, VIA_ALEN_ALIGN); + struct mpls_route *rt; + + rt = kzalloc(ALIGN(sizeof(*rt) + num_nh * sizeof(*rt->rt_nh), + VIA_ALEN_ALIGN) + + num_nh * max_alen_aligned, + GFP_KERNEL); + if (rt) { + rt->rt_nhn = num_nh; + rt->rt_max_alen = max_alen_aligned; + } + + return rt; +} + +static void mpls_rt_free(struct mpls_route *rt) +{ + if (rt) + kfree_rcu(rt, rt_rcu); +} + +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 >= MPLS_LABEL_FIRST_UNRESERVED)) + rtmsg_lfib(event, index, rt, nlh, net, portid, nlm_flags); +} + +static void mpls_route_update(struct net *net, unsigned index, + struct mpls_route *new, + const struct nl_info *info) +{ + struct mpls_route __rcu **platform_label; + struct mpls_route *rt; + + ASSERT_RTNL(); + + platform_label = rtnl_dereference(net->mpls.platform_label); + rt = rtnl_dereference(platform_label[index]); + rcu_assign_pointer(platform_label[index], new); + + mpls_notify_route(net, index, rt, new, info); + + /* If we removed a route free it now */ + mpls_rt_free(rt); +} + +static unsigned find_free_label(struct net *net) +{ + struct mpls_route __rcu **platform_label; + size_t platform_labels; + unsigned index; + + platform_label = rtnl_dereference(net->mpls.platform_label); + platform_labels = net->mpls.platform_labels; + for (index = MPLS_LABEL_FIRST_UNRESERVED; index < platform_labels; + index++) { + if (!rtnl_dereference(platform_label[index])) + return index; + } + return LABEL_NOT_SPECIFIED; +} + +#if IS_ENABLED(CONFIG_INET) +static struct net_device *inet_fib_lookup_dev(struct net *net, + const void *addr) +{ + struct net_device *dev; + 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)) + return ERR_CAST(rt); + + dev = rt->dst.dev; + dev_hold(dev); + + ip_rt_put(rt); + + return dev; +} +#else +static struct net_device *inet_fib_lookup_dev(struct net *net, + const void *addr) +{ + return ERR_PTR(-EAFNOSUPPORT); +} +#endif + +#if IS_ENABLED(CONFIG_IPV6) +static struct net_device *inet6_fib_lookup_dev(struct net *net, + const void *addr) +{ + struct net_device *dev; + struct dst_entry *dst; + struct flowi6 fl6; + + if (!ipv6_stub) + return ERR_PTR(-EAFNOSUPPORT); + + memset(&fl6, 0, sizeof(fl6)); + memcpy(&fl6.daddr, addr, sizeof(struct in6_addr)); + dst = ipv6_stub->ipv6_dst_lookup_flow(net, NULL, &fl6, NULL); + if (IS_ERR(dst)) + return ERR_CAST(dst); + + dev = dst->dev; + dev_hold(dev); + dst_release(dst); + + return dev; +} +#else +static struct net_device *inet6_fib_lookup_dev(struct net *net, + const void *addr) +{ + return ERR_PTR(-EAFNOSUPPORT); +} +#endif + +static struct net_device *find_outdev(struct net *net, + struct mpls_route *rt, + struct mpls_nh *nh, int oif) +{ + struct net_device *dev = NULL; + + if (!oif) { + switch (nh->nh_via_table) { + case NEIGH_ARP_TABLE: + dev = inet_fib_lookup_dev(net, mpls_nh_via(rt, nh)); + break; + case NEIGH_ND_TABLE: + dev = inet6_fib_lookup_dev(net, mpls_nh_via(rt, nh)); + break; + case NEIGH_LINK_TABLE: + break; + } + } else { + dev = dev_get_by_index(net, oif); + } + + if (!dev) + return ERR_PTR(-ENODEV); + + if (IS_ERR(dev)) + return dev; + + /* The caller is holding rtnl anyways, so release the dev reference */ + dev_put(dev); + + return dev; +} + +static int mpls_nh_assign_dev(struct net *net, struct mpls_route *rt, + struct mpls_nh *nh, int oif) +{ + struct net_device *dev = NULL; + int err = -ENODEV; + + dev = find_outdev(net, rt, nh, oif); + if (IS_ERR(dev)) { + err = PTR_ERR(dev); + dev = NULL; + goto errout; + } + + /* Ensure this is a supported device */ + err = -EINVAL; + if (!mpls_dev_get(dev)) + goto errout; + + if ((nh->nh_via_table == NEIGH_LINK_TABLE) && + (dev->addr_len != nh->nh_via_alen)) + goto errout; + + RCU_INIT_POINTER(nh->nh_dev, dev); + + return 0; + +errout: + return err; +} + +static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg, + struct mpls_route *rt) +{ + struct net *net = cfg->rc_nlinfo.nl_net; + struct mpls_nh *nh = rt->rt_nh; + int err; + int i; + + if (!nh) + return -ENOMEM; + + err = -EINVAL; + /* Ensure only a supported number of labels are present */ + if (cfg->rc_output_labels > MAX_NEW_LABELS) + goto errout; + + nh->nh_labels = cfg->rc_output_labels; + for (i = 0; i < nh->nh_labels; i++) + nh->nh_label[i] = cfg->rc_output_label[i]; + + nh->nh_via_table = cfg->rc_via_table; + memcpy(__mpls_nh_via(rt, nh), cfg->rc_via, cfg->rc_via_alen); + nh->nh_via_alen = cfg->rc_via_alen; + + err = mpls_nh_assign_dev(net, rt, nh, cfg->rc_ifindex); + if (err) + goto errout; + + return 0; + +errout: + return err; +} + +static int mpls_nh_build(struct net *net, struct mpls_route *rt, + struct mpls_nh *nh, int oif, + struct nlattr *via, struct nlattr *newdst) +{ + int err = -ENOMEM; + + if (!nh) + goto errout; + + if (newdst) { + err = nla_get_labels(newdst, MAX_NEW_LABELS, + &nh->nh_labels, nh->nh_label); + if (err) + goto errout; + } + + if (via) { + err = nla_get_via(via, &nh->nh_via_alen, &nh->nh_via_table, + __mpls_nh_via(rt, nh)); + if (err) + goto errout; + } else { + nh->nh_via_table = MPLS_NEIGH_TABLE_UNSPEC; + } + + err = mpls_nh_assign_dev(net, rt, nh, oif); + if (err) + goto errout; + + return 0; + +errout: + return err; +} + +static int mpls_count_nexthops(struct rtnexthop *rtnh, int len, + u8 cfg_via_alen, u8 *max_via_alen) +{ + int nhs = 0; + int remaining = len; + + if (!rtnh) { + *max_via_alen = cfg_via_alen; + return 1; + } + + *max_via_alen = 0; + + while (rtnh_ok(rtnh, remaining)) { + struct nlattr *nla, *attrs = rtnh_attrs(rtnh); + int attrlen; + + attrlen = rtnh_attrlen(rtnh); + nla = nla_find(attrs, attrlen, RTA_VIA); + if (nla && nla_len(nla) >= + offsetof(struct rtvia, rtvia_addr)) { + int via_alen = nla_len(nla) - + offsetof(struct rtvia, rtvia_addr); + + if (via_alen <= MAX_VIA_ALEN) + *max_via_alen = max_t(u16, *max_via_alen, + via_alen); + } + + nhs++; + rtnh = rtnh_next(rtnh, &remaining); + } + + /* leftover implies invalid nexthop configuration, discard it */ + return remaining > 0 ? 0 : nhs; +} + +static int mpls_nh_build_multi(struct mpls_route_config *cfg, + struct mpls_route *rt) +{ + struct rtnexthop *rtnh = cfg->rc_mp; + struct nlattr *nla_via, *nla_newdst; + int remaining = cfg->rc_mp_len; + int nhs = 0; + int err = 0; + + change_nexthops(rt) { + int attrlen; + + nla_via = NULL; + nla_newdst = NULL; + + err = -EINVAL; + if (!rtnh_ok(rtnh, remaining)) + goto errout; + + /* neither weighted multipath nor any flags + * are supported + */ + if (rtnh->rtnh_hops || rtnh->rtnh_flags) + goto errout; + + attrlen = rtnh_attrlen(rtnh); + if (attrlen > 0) { + struct nlattr *attrs = rtnh_attrs(rtnh); + + nla_via = nla_find(attrs, attrlen, RTA_VIA); + nla_newdst = nla_find(attrs, attrlen, RTA_NEWDST); + } + + err = mpls_nh_build(cfg->rc_nlinfo.nl_net, rt, nh, + rtnh->rtnh_ifindex, nla_via, + nla_newdst); + if (err) + goto errout; + + rtnh = rtnh_next(rtnh, &remaining); + nhs++; + } endfor_nexthops(rt); + + rt->rt_nhn = nhs; + + return 0; + +errout: + return err; +} + +static bool mpls_label_ok(struct net *net, unsigned int *index) +{ + bool is_ok = true; + + /* Reserved labels may not be set */ + if (*index < MPLS_LABEL_FIRST_UNRESERVED) + is_ok = false; + + /* The full 20 bit range may not be supported. */ + if (is_ok && *index >= net->mpls.platform_labels) + is_ok = false; + + *index = array_index_nospec(*index, net->mpls.platform_labels); + return is_ok; +} + +static int mpls_route_add(struct mpls_route_config *cfg) +{ + struct mpls_route __rcu **platform_label; + struct net *net = cfg->rc_nlinfo.nl_net; + struct mpls_route *rt, *old; + int err = -EINVAL; + u8 max_via_alen; + unsigned index; + int nhs; + + 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); + } + + if (!mpls_label_ok(net, &index)) + goto errout; + + /* Append makes no sense with mpls */ + err = -EOPNOTSUPP; + if (cfg->rc_nlflags & NLM_F_APPEND) + goto errout; + + err = -EEXIST; + platform_label = rtnl_dereference(net->mpls.platform_label); + old = rtnl_dereference(platform_label[index]); + 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 = -EINVAL; + nhs = mpls_count_nexthops(cfg->rc_mp, cfg->rc_mp_len, + cfg->rc_via_alen, &max_via_alen); + if (nhs == 0) + goto errout; + + err = -ENOMEM; + rt = mpls_rt_alloc(nhs, max_via_alen); + if (!rt) + goto errout; + + rt->rt_protocol = cfg->rc_protocol; + rt->rt_payload_type = cfg->rc_payload_type; + + if (cfg->rc_mp) + err = mpls_nh_build_multi(cfg, rt); + else + err = mpls_nh_build_from_cfg(cfg, rt); + if (err) + goto freert; + + mpls_route_update(net, index, rt, &cfg->rc_nlinfo); + + return 0; + +freert: + mpls_rt_free(rt); +errout: + 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; + + if (!mpls_label_ok(net, &index)) + goto errout; + + mpls_route_update(net, index, NULL, &cfg->rc_nlinfo); + + err = 0; +errout: + return err; +} + +#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); +} + +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); + + err = mpls_dev_sysctl_register(dev, mdev); + if (err) + goto free; + + rcu_assign_pointer(dev->mpls_ptr, mdev); + + return mdev; + +free: + kfree(mdev); + return ERR_PTR(err); +} + +static void mpls_ifdown(struct net_device *dev) +{ + struct mpls_route __rcu **platform_label; + struct net *net = dev_net(dev); + struct mpls_dev *mdev; + unsigned index; + + platform_label = rtnl_dereference(net->mpls.platform_label); + for (index = 0; index < net->mpls.platform_labels; index++) { + struct mpls_route *rt = rtnl_dereference(platform_label[index]); + if (!rt) + continue; + for_nexthops(rt) { + if (rtnl_dereference(nh->nh_dev) != dev) + continue; + nh->nh_dev = NULL; + } endfor_nexthops(rt); + } + + mdev = mpls_dev_get(dev); + if (!mdev) + return; + + mpls_dev_sysctl_unregister(mdev); + + RCU_INIT_POINTER(dev->mpls_ptr, NULL); + + kfree_rcu(mdev, rcu); +} + +static int mpls_dev_notify(struct notifier_block *this, unsigned long event, + void *ptr) +{ + struct net_device *dev = netdev_notifier_info_to_dev(ptr); + struct mpls_dev *mdev; + + switch(event) { + 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; + + case NETDEV_UNREGISTER: + mpls_ifdown(dev); + break; + 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; + } + return NOTIFY_OK; +} + +static struct notifier_block mpls_dev_notifier = { + .notifier_call = mpls_dev_notify, +}; + +static int nla_put_via(struct sk_buff *skb, + u8 table, const void *addr, int alen) +{ + static const int table_to_family[NEIGH_NR_TABLES + 1] = { + AF_INET, AF_INET6, AF_DECnet, AF_PACKET, + }; + struct nlattr *nla; + struct rtvia *via; + int family = AF_UNSPEC; + + nla = nla_reserve(skb, RTA_VIA, alen + 2); + if (!nla) + return -EMSGSIZE; + + if (table <= NEIGH_NR_TABLES) + family = table_to_family[table]; + + via = nla_data(nla); + via->rtvia_family = family; + memcpy(via->rtvia_addr, addr, alen); + return 0; +} + +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; +} +EXPORT_SYMBOL_GPL(nla_put_labels); + +int nla_get_labels(const struct nlattr *nla, + u32 max_labels, u8 *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; + + switch (dec.label) { + case MPLS_LABEL_IMPLNULL: + /* RFC3032: This is a label that an LSR may + * assign and distribute, but which never + * actually appears in the encapsulation. + */ + return -EINVAL; + } + + label[i] = dec.label; + } + *labels = nla_labels; + return 0; +} +EXPORT_SYMBOL_GPL(nla_get_labels); + +int nla_get_via(const struct nlattr *nla, u8 *via_alen, + u8 *via_table, u8 via_addr[]) +{ + struct rtvia *via = nla_data(nla); + int err = -EINVAL; + int alen; + + if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) + goto errout; + alen = nla_len(nla) - + offsetof(struct rtvia, rtvia_addr); + if (alen > MAX_VIA_ALEN) + goto errout; + + /* Validate the address family */ + switch (via->rtvia_family) { + case AF_PACKET: + *via_table = NEIGH_LINK_TABLE; + break; + case AF_INET: + *via_table = NEIGH_ARP_TABLE; + if (alen != 4) + goto errout; + break; + case AF_INET6: + *via_table = NEIGH_ND_TABLE; + if (alen != 16) + goto errout; + break; + default: + /* Unsupported address family */ + goto errout; + } + + memcpy(via_addr, via->rtvia_addr, alen); + *via_alen = alen; + err = 0; + +errout: + return err; +} + +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_via_table = MPLS_NEIGH_TABLE_UNSPEC; + 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: + { + u8 label_count; + if (nla_get_labels(nla, 1, &label_count, + &cfg->rc_label)) + goto errout; + + if (!mpls_label_ok(cfg->rc_nlinfo.nl_net, + &cfg->rc_label)) + goto errout; + break; + } + case RTA_VIA: + { + if (nla_get_via(nla, &cfg->rc_via_alen, + &cfg->rc_via_table, cfg->rc_via)) + goto errout; + break; + } + case RTA_MULTIPATH: + { + cfg->rc_mp = nla_data(nla); + cfg->rc_mp_len = nla_len(nla); + 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) +{ + struct net_device *dev; + 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 (nla_put_labels(skb, RTA_DST, 1, &label)) + goto nla_put_failure; + if (rt->rt_nhn == 1) { + const struct mpls_nh *nh = rt->rt_nh; + + if (nh->nh_labels && + nla_put_labels(skb, RTA_NEWDST, nh->nh_labels, + nh->nh_label)) + goto nla_put_failure; + if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC && + nla_put_via(skb, nh->nh_via_table, mpls_nh_via(rt, nh), + nh->nh_via_alen)) + goto nla_put_failure; + dev = rtnl_dereference(nh->nh_dev); + if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex)) + goto nla_put_failure; + } else { + struct rtnexthop *rtnh; + struct nlattr *mp; + + mp = nla_nest_start(skb, RTA_MULTIPATH); + if (!mp) + goto nla_put_failure; + + for_nexthops(rt) { + rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); + if (!rtnh) + goto nla_put_failure; + + dev = rtnl_dereference(nh->nh_dev); + if (dev) + rtnh->rtnh_ifindex = dev->ifindex; + if (nh->nh_labels && nla_put_labels(skb, RTA_NEWDST, + nh->nh_labels, + nh->nh_label)) + goto nla_put_failure; + if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC && + nla_put_via(skb, nh->nh_via_table, + mpls_nh_via(rt, nh), + nh->nh_via_alen)) + goto nla_put_failure; + + /* length of rtnetlink header + attributes */ + rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh; + } endfor_nexthops(rt); + + nla_nest_end(skb, mp); + } + + 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); + struct mpls_route __rcu **platform_label; + size_t platform_labels; + unsigned int index; + + ASSERT_RTNL(); + + index = cb->args[0]; + if (index < MPLS_LABEL_FIRST_UNRESERVED) + index = MPLS_LABEL_FIRST_UNRESERVED; + + platform_label = rtnl_dereference(net->mpls.platform_label); + platform_labels = net->mpls.platform_labels; + for (; index < platform_labels; index++) { + struct mpls_route *rt; + rt = rtnl_dereference(platform_label[index]); + 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; +} + +static inline size_t lfib_nlmsg_size(struct mpls_route *rt) +{ + size_t payload = + NLMSG_ALIGN(sizeof(struct rtmsg)) + + nla_total_size(4); /* RTA_DST */ + + if (rt->rt_nhn == 1) { + struct mpls_nh *nh = rt->rt_nh; + + if (nh->nh_dev) + payload += nla_total_size(4); /* RTA_OIF */ + if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC) /* RTA_VIA */ + payload += nla_total_size(2 + nh->nh_via_alen); + if (nh->nh_labels) /* RTA_NEWDST */ + payload += nla_total_size(nh->nh_labels * 4); + } else { + /* each nexthop is packed in an attribute */ + size_t nhsize = 0; + + for_nexthops(rt) { + nhsize += nla_total_size(sizeof(struct rtnexthop)); + /* RTA_VIA */ + if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC) + nhsize += nla_total_size(2 + nh->nh_via_alen); + if (nh->nh_labels) + nhsize += nla_total_size(nh->nh_labels * 4); + } endfor_nexthops(rt); + /* nested attribute */ + payload += nla_total_size(nhsize); + } + + 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); +} + +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 > MPLS_LABEL_IPV4NULL) { + struct net_device *lo = net->loopback_dev; + rt0 = mpls_rt_alloc(1, lo->addr_len); + if (!rt0) + goto nort0; + RCU_INIT_POINTER(rt0->rt_nh->nh_dev, lo); + rt0->rt_protocol = RTPROT_KERNEL; + rt0->rt_payload_type = MPT_IPV4; + rt0->rt_nh->nh_via_table = NEIGH_LINK_TABLE; + rt0->rt_nh->nh_via_alen = lo->addr_len; + memcpy(__mpls_nh_via(rt0, rt0->rt_nh), lo->dev_addr, + lo->addr_len); + } + if (limit > MPLS_LABEL_IPV6NULL) { + struct net_device *lo = net->loopback_dev; + rt2 = mpls_rt_alloc(1, lo->addr_len); + if (!rt2) + goto nort2; + RCU_INIT_POINTER(rt2->rt_nh->nh_dev, lo); + rt2->rt_protocol = RTPROT_KERNEL; + rt2->rt_payload_type = MPT_IPV6; + rt2->rt_nh->nh_via_table = NEIGH_LINK_TABLE; + rt2->rt_nh->nh_via_alen = lo->addr_len; + memcpy(__mpls_nh_via(rt2, rt2->rt_nh), lo->dev_addr, + lo->addr_len); + } + + rtnl_lock(); + /* Remember the original table */ + old = rtnl_dereference(net->mpls.platform_label); + 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); + + /* 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 <= MPLS_LABEL_IPV6NULL) && + (limit > MPLS_LABEL_IPV6NULL)) { + RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6NULL], rt2); + rt2 = NULL; + } + + if ((old_limit <= MPLS_LABEL_IPV4NULL) && + (limit > MPLS_LABEL_IPV4NULL)) { + RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4NULL], rt0); + rt0 = NULL; + } + + /* Update the global pointers */ + net->mpls.platform_labels = limit; + rcu_assign_pointer(net->mpls.platform_label, labels); + + 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 const struct ctl_table mpls_table[] = { + { + .procname = "platform_labels", + .data = NULL, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = mpls_platform_labels, + }, + { } +}; + +static int mpls_net_init(struct net *net) +{ + struct ctl_table *table; + + net->mpls.platform_labels = 0; + net->mpls.platform_label = NULL; + + 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) { + kfree(table); + return -ENOMEM; + } + + return 0; +} + +static void mpls_net_exit(struct net *net) +{ + struct mpls_route __rcu **platform_label; + size_t platform_labels; + struct ctl_table *table; + unsigned int index; + + table = net->mpls.ctl->ctl_table_arg; + unregister_net_sysctl_table(net->mpls.ctl); + kfree(table); + + /* An rcu grace period has passed since there was a device in + * the network namespace (and thus the last in flight 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(); + 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); + mpls_notify_route(net, index, rt, NULL, NULL); + mpls_rt_free(rt); + } + rtnl_unlock(); + + kvfree(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); + + 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); + 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) +{ + rtnl_unregister_all(PF_MPLS); + 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); |