diff options
Diffstat (limited to 'net/mpls')
| -rw-r--r-- | net/mpls/Kconfig | 21 | ||||
| -rw-r--r-- | net/mpls/Makefile | 3 | ||||
| -rw-r--r-- | net/mpls/af_mpls.c | 1023 | ||||
| -rw-r--r-- | net/mpls/internal.h | 59 |
4 files changed, 1106 insertions, 0 deletions
diff --git a/net/mpls/Kconfig b/net/mpls/Kconfig index 37421db88965..17bde799c854 100644 --- a/net/mpls/Kconfig +++ b/net/mpls/Kconfig @@ -1,9 +1,30 @@ # # MPLS configuration # + +menuconfig MPLS + bool "MultiProtocol Label Switching" + default n + ---help--- + MultiProtocol Label Switching routes packets through logical + circuits. Originally conceived as a way of routing packets at + hardware speeds (before hardware was capable of routing ipv4 packets), + MPLS remains a simple way of making tunnels. + + If you have not heard of MPLS you probably want to say N here. + +if MPLS + config NET_MPLS_GSO tristate "MPLS: GSO support" help This is helper module to allow segmentation of non-MPLS GSO packets that have had MPLS stack entries pushed onto them and thus become MPLS GSO packets. + +config MPLS_ROUTING + tristate "MPLS: routing support" + help + Add support for forwarding of mpls packets. + +endif # MPLS diff --git a/net/mpls/Makefile b/net/mpls/Makefile index 6dec088c2d0f..65bbe68c72e6 100644 --- a/net/mpls/Makefile +++ b/net/mpls/Makefile @@ -2,3 +2,6 @@ # Makefile for MPLS. # obj-$(CONFIG_NET_MPLS_GSO) += mpls_gso.o +obj-$(CONFIG_MPLS_ROUTING) += mpls_router.o + +mpls_router-y := af_mpls.o diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c new file mode 100644 index 000000000000..db8a2ea6d4de --- /dev/null +++ b/net/mpls/af_mpls.c @@ -0,0 +1,1023 @@ +#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> +#include "internal.h" + +#define LABEL_NOT_SPECIFIED (1<<20) +#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 __rcu *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; + u8 rt_via_alen; + u8 rt_via_table; + u8 rt_via[0]; +}; + +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 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; + bool success = true; + + /* 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; + + /* Use ip_hdr to find the ip protocol version */ + hdr4 = ip_hdr(skb); + 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 = rcu_dereference(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 <= 1) + 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_table, 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 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; + u16 rc_via_table; + u16 rc_via_alen; + u8 rc_via[MAX_VIA_ALEN]; + u32 rc_label; + u32 rc_output_labels; + u32 rc_output_label[MAX_NEW_LABELS]; + u32 rc_nlflags; + struct nl_info rc_nlinfo; +}; + +static struct mpls_route *mpls_rt_alloc(size_t alen) +{ + struct mpls_route *rt; + + rt = kzalloc(sizeof(*rt) + alen, GFP_KERNEL); + 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_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); +} + +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 __rcu **platform_label; + struct mpls_route *rt, *old = NULL; + + ASSERT_RTNL(); + + 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); + old = rt; + } + + mpls_notify_route(net, index, old, new, info); + + /* If we removed a route free it now */ + mpls_rt_free(old); +} + +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 = 16; index < platform_labels; index++) { + if (!rtnl_dereference(platform_label[index])) + return index; + } + return LABEL_NOT_SPECIFIED; +} + +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 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_table == NEIGH_LINK_TABLE) && + (dev->addr_len != cfg->rc_via_alen)) + 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 = -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; + RCU_INIT_POINTER(rt->rt_dev, dev); + rt->rt_via_table = cfg->rc_via_table; + 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; +} + +static void mpls_ifdown(struct net_device *dev) +{ + 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; + if (rtnl_dereference(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 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; +} + +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; +} + +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); + if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) + goto errout; + cfg->rc_via_alen = nla_len(nla) - + offsetof(struct rtvia, rtvia_addr); + if (cfg->rc_via_alen > MAX_VIA_ALEN) + goto errout; + + /* Validate the address family */ + switch(via->rtvia_family) { + case AF_PACKET: + cfg->rc_via_table = NEIGH_LINK_TABLE; + break; + case AF_INET: + cfg->rc_via_table = NEIGH_ARP_TABLE; + if (cfg->rc_via_alen != 4) + goto errout; + break; + case AF_INET6: + cfg->rc_via_table = NEIGH_ND_TABLE; + 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) +{ + 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 (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_table, rt->rt_via, rt->rt_via_alen)) + goto nla_put_failure; + dev = rtnl_dereference(rt->rt_dev); + if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex)) + 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); + struct mpls_route __rcu **platform_label; + size_t platform_labels; + unsigned int index; + + ASSERT_RTNL(); + + index = cb->args[0]; + if (index < 16) + index = 16; + + 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(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); +} + +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; + RCU_INIT_POINTER(rt0->rt_dev, lo); + rt0->rt_protocol = RTPROT_KERNEL; + rt0->rt_via_table = NEIGH_LINK_TABLE; + 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; + RCU_INIT_POINTER(rt2->rt_dev, lo); + rt2->rt_protocol = RTPROT_KERNEL; + rt2->rt_via_table = NEIGH_LINK_TABLE; + memcpy(rt2->rt_via, 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, 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)) { + RCU_INIT_POINTER(labels[LABEL_IPV6_EXPLICIT_NULL], rt2); + rt2 = NULL; + } + + if ((old_limit <= LABEL_IPV4_EXPLICIT_NULL) && + (limit > LABEL_IPV4_EXPLICIT_NULL)) { + RCU_INIT_POINTER(labels[LABEL_IPV4_EXPLICIT_NULL], 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 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) + 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); diff --git a/net/mpls/internal.h b/net/mpls/internal.h new file mode 100644 index 000000000000..fb6de92052c4 --- /dev/null +++ b/net/mpls/internal.h @@ -0,0 +1,59 @@ +#ifndef MPLS_INTERNAL_H +#define MPLS_INTERNAL_H + +#define LABEL_IPV4_EXPLICIT_NULL 0 /* RFC3032 */ +#define LABEL_ROUTER_ALERT_LABEL 1 /* RFC3032 */ +#define LABEL_IPV6_EXPLICIT_NULL 2 /* RFC3032 */ +#define LABEL_IMPLICIT_NULL 3 /* RFC3032 */ +#define LABEL_ENTROPY_INDICATOR 7 /* RFC6790 */ +#define LABEL_GAL 13 /* RFC5586 */ +#define LABEL_OAM_ALERT 14 /* RFC3429 */ +#define LABEL_EXTENSION 15 /* RFC7274 */ + + +struct mpls_shim_hdr { + __be32 label_stack_entry; +}; + +struct mpls_entry_decoded { + u32 label; + u8 ttl; + u8 tc; + u8 bos; +}; + +struct sk_buff; + +static inline struct mpls_shim_hdr *mpls_hdr(const struct sk_buff *skb) +{ + return (struct mpls_shim_hdr *)skb_network_header(skb); +} + +static inline struct mpls_shim_hdr mpls_entry_encode(u32 label, unsigned ttl, unsigned tc, bool bos) +{ + struct mpls_shim_hdr result; + result.label_stack_entry = + cpu_to_be32((label << MPLS_LS_LABEL_SHIFT) | + (tc << MPLS_LS_TC_SHIFT) | + (bos ? (1 << MPLS_LS_S_SHIFT) : 0) | + (ttl << MPLS_LS_TTL_SHIFT)); + return result; +} + +static inline struct mpls_entry_decoded mpls_entry_decode(struct mpls_shim_hdr *hdr) +{ + struct mpls_entry_decoded result; + unsigned entry = be32_to_cpu(hdr->label_stack_entry); + + result.label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT; + result.ttl = (entry & MPLS_LS_TTL_MASK) >> MPLS_LS_TTL_SHIFT; + result.tc = (entry & MPLS_LS_TC_MASK) >> MPLS_LS_TC_SHIFT; + result.bos = (entry & MPLS_LS_S_MASK) >> MPLS_LS_S_SHIFT; + + return result; +} + +int nla_put_labels(struct sk_buff *skb, int attrtype, u8 labels, const u32 label[]); +int nla_get_labels(const struct nlattr *nla, u32 max_labels, u32 *labels, u32 label[]); + +#endif /* MPLS_INTERNAL_H */ |