#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/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_validate_mtu(skb, mtu)) return false; return true; } EXPORT_SYMBOL_GPL(mpls_pkt_too_big); static u32 mpls_multipath_hash(struct mpls_route *rt, struct sk_buff *skb) { struct mpls_entry_decoded dec; unsigned int mpls_hdr_len = 0; struct mpls_shim_hdr *hdr; bool eli_seen = false; int label_index; u32 hash = 0; for (label_index = 0; label_index < MAX_MP_SELECT_LABELS; label_index++) { mpls_hdr_len += sizeof(*hdr); if (!pskb_may_pull(skb, mpls_hdr_len)) 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; } if (!dec.bos) continue; /* found bottom label; does skb have room for a header? */ if (pskb_may_pull(skb, mpls_hdr_len + sizeof(struct iphdr))) { const struct iphdr *v4hdr; v4hdr = (const struct iphdr *)(hdr + 1); 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, mpls_hdr_len + sizeof(struct ipv6hdr))) { const struct ipv6hdr *v6hdr; v6hdr = (const struct ipv6hdr *)(hdr + 1); hash = __ipv6_addr_jhash(&v6hdr->saddr, hash); hash = __ipv6_addr_jhash(&v6hdr->daddr, hash); hash = jhash_1word(v6hdr->nexthdr, hash); } } break; } return hash; } static struct mpls_nh *mpls_select_multipath(struct mpls_route *rt, struct sk_buff *skb) { int alive = ACCESS_ONCE(rt->rt_nhn_alive); u32 hash = 0; int nh_index = 0; int n = 0; /* No need to look further into packet if there's only * one path */ if (rt->rt_nhn == 1) goto out; if (alive <= 0) return NULL; hash = mpls_multipath_hash(rt, skb); nh_index = hash % alive; if (alive == rt->rt_nhn) goto out; for_nexthops(rt) { if (nh->nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) continue; if (n == nh_index) return nh; n++; } endfor_nexthops(rt); 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); rt = mpls_route_input_rcu(net, dec.label); if (!rt) goto drop; nh = mpls_select_multipath(rt, skb); if (!nh) goto drop; /* Find the output device */ out_dev = rcu_dereference(nh->nh_dev); if (!mpls_output_possible(out_dev)) goto drop; /* Pop the label */ skb_pull(skb, sizeof(*hdr)); skb_reset_network_header(skb); skb_orphan(skb); 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_nhn_alive = 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; int err; if (!ipv6_stub) return ERR_PTR(-EAFNOSUPPORT); memset(&fl6, 0, sizeof(fl6)); memcpy(&fl6.daddr, addr, sizeof(struct in6_addr)); err = ipv6_stub->ipv6_dst_lookup(net, NULL, &dst, &fl6); if (err) return ERR_PTR(err); 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); if (!(dev->flags & IFF_UP)) { nh->nh_flags |= RTNH_F_DEAD; } else { unsigned int flags; flags = dev_get_flags(dev); if (!(flags & (IFF_RUNNING | IFF_LOWER_UP))) nh->nh_flags |= RTNH_F_LINKDOWN; } 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; if (nh->nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) rt->rt_nhn_alive--; 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; if (nh->nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) rt->rt_nhn_alive--; rtnh = rtnh_next(rtnh, &remaining); nhs++; } endfor_nexthops(rt); rt->rt_nhn = nhs; return 0; errout: return err; } 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); } /* Reserved labels may not be set */ if (index < MPLS_LABEL_FIRST_UNRESERVED) goto errout; /* The full 20 bit range may not be supported. */ if (index >= net->mpls.platform_labels) 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; /* Reserved labels may not be removed */ if (index < MPLS_LABEL_FIRST_UNRESERVED) 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, &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, int event) { struct mpls_route __rcu **platform_label; struct net *net = dev_net(dev); 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; change_nexthops(rt) { if (rtnl_dereference(nh->nh_dev) != dev) continue; switch (event) { case NETDEV_DOWN: case NETDEV_UNREGISTER: nh->nh_flags |= RTNH_F_DEAD; /* fall through */ case NETDEV_CHANGE: nh->nh_flags |= RTNH_F_LINKDOWN; ACCESS_ONCE(rt->rt_nhn_alive) = rt->rt_nhn_alive - 1; break; } if (event == NETDEV_UNREGISTER) RCU_INIT_POINTER(nh->nh_dev, NULL); } endfor_nexthops(rt); } } static void mpls_ifup(struct net_device *dev, unsigned int nh_flags) { struct mpls_route __rcu **platform_label; struct net *net = dev_net(dev); unsigned index; int alive; 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; alive = 0; change_nexthops(rt) { struct net_device *nh_dev = rtnl_dereference(nh->nh_dev); if (!(nh->nh_flags & nh_flags)) { alive++; continue; } if (nh_dev != dev) continue; alive++; nh->nh_flags &= ~nh_flags; } endfor_nexthops(rt); ACCESS_ONCE(rt->rt_nhn_alive) = alive; } } 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; unsigned int flags; if (event == NETDEV_REGISTER) { /* For now just support Ethernet, IPGRE, SIT and IPIP devices */ if (dev->type == ARPHRD_ETHER || dev->type == ARPHRD_LOOPBACK || dev->type == ARPHRD_IPGRE || dev->type == ARPHRD_SIT || dev->type == ARPHRD_TUNNEL) { mdev = mpls_add_dev(dev); if (IS_ERR(mdev)) return notifier_from_errno(PTR_ERR(mdev)); } return NOTIFY_OK; } mdev = mpls_dev_get(dev); if (!mdev) return NOTIFY_OK; switch (event) { case NETDEV_DOWN: mpls_ifdown(dev, event); break; case NETDEV_UP: flags = dev_get_flags(dev); if (flags & (IFF_RUNNING | IFF_LOWER_UP)) mpls_ifup(dev, RTNH_F_DEAD | RTNH_F_LINKDOWN); else mpls_ifup(dev, RTNH_F_DEAD); break; case NETDEV_CHANGE: flags = dev_get_flags(dev); if (flags & (IFF_RUNNING | IFF_LOWER_UP)) mpls_ifup(dev, RTNH_F_DEAD | RTNH_F_LINKDOWN); else mpls_ifdown(dev, event); break; case NETDEV_UNREGISTER: mpls_ifdown(dev, event); mdev = mpls_dev_get(dev); if (mdev) { mpls_dev_sysctl_unregister(mdev); RCU_INIT_POINTER(dev->mpls_ptr, NULL); kfree_rcu(mdev, rcu); } 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; /* Reserved labels may not be set */ if (cfg->rc_label < MPLS_LABEL_FIRST_UNRESERVED) 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; if (nh->nh_flags & RTNH_F_LINKDOWN) rtm->rtm_flags |= RTNH_F_LINKDOWN; if (nh->nh_flags & RTNH_F_DEAD) rtm->rtm_flags |= RTNH_F_DEAD; } else { struct rtnexthop *rtnh; struct nlattr *mp; int dead = 0; int linkdown = 0; 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_flags & RTNH_F_LINKDOWN) { rtnh->rtnh_flags |= RTNH_F_LINKDOWN; linkdown++; } if (nh->nh_flags & RTNH_F_DEAD) { rtnh->rtnh_flags |= RTNH_F_DEAD; dead++; } 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); if (linkdown == rt->rt_nhn) rtm->rtm_flags |= RTNH_F_LINKDOWN; if (dead == rt->rt_nhn) rtm->rtm_flags |= RTNH_F_DEAD; 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_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);