diff options
Diffstat (limited to 'net/ipv6/ndisc.c')
| -rw-r--r-- | net/ipv6/ndisc.c | 2061 |
1 files changed, 2061 insertions, 0 deletions
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c new file mode 100644 index 000000000..8c5a99fe6 --- /dev/null +++ b/net/ipv6/ndisc.c @@ -0,0 +1,2061 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Neighbour Discovery for IPv6 + * Linux INET6 implementation + * + * Authors: + * Pedro Roque <roque@di.fc.ul.pt> + * Mike Shaver <shaver@ingenia.com> + */ + +/* + * Changes: + * + * Alexey I. Froloff : RFC6106 (DNSSL) support + * Pierre Ynard : export userland ND options + * through netlink (RDNSS support) + * Lars Fenneberg : fixed MTU setting on receipt + * of an RA. + * Janos Farkas : kmalloc failure checks + * Alexey Kuznetsov : state machine reworked + * and moved to net/core. + * Pekka Savola : RFC2461 validation + * YOSHIFUJI Hideaki @USAGI : Verify ND options properly + */ + +#define pr_fmt(fmt) "ICMPv6: " fmt + +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/sockios.h> +#include <linux/sched.h> +#include <linux/net.h> +#include <linux/in6.h> +#include <linux/route.h> +#include <linux/init.h> +#include <linux/rcupdate.h> +#include <linux/slab.h> +#ifdef CONFIG_SYSCTL +#include <linux/sysctl.h> +#endif + +#include <linux/if_addr.h> +#include <linux/if_ether.h> +#include <linux/if_arp.h> +#include <linux/ipv6.h> +#include <linux/icmpv6.h> +#include <linux/jhash.h> + +#include <net/sock.h> +#include <net/snmp.h> + +#include <net/ipv6.h> +#include <net/protocol.h> +#include <net/ndisc.h> +#include <net/ip6_route.h> +#include <net/addrconf.h> +#include <net/icmp.h> + +#include <net/netlink.h> +#include <linux/rtnetlink.h> + +#include <net/flow.h> +#include <net/ip6_checksum.h> +#include <net/inet_common.h> +#include <linux/proc_fs.h> + +#include <linux/netfilter.h> +#include <linux/netfilter_ipv6.h> + +static u32 ndisc_hash(const void *pkey, + const struct net_device *dev, + __u32 *hash_rnd); +static bool ndisc_key_eq(const struct neighbour *neigh, const void *pkey); +static bool ndisc_allow_add(const struct net_device *dev, + struct netlink_ext_ack *extack); +static int ndisc_constructor(struct neighbour *neigh); +static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb); +static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb); +static int pndisc_constructor(struct pneigh_entry *n); +static void pndisc_destructor(struct pneigh_entry *n); +static void pndisc_redo(struct sk_buff *skb); +static int ndisc_is_multicast(const void *pkey); + +static const struct neigh_ops ndisc_generic_ops = { + .family = AF_INET6, + .solicit = ndisc_solicit, + .error_report = ndisc_error_report, + .output = neigh_resolve_output, + .connected_output = neigh_connected_output, +}; + +static const struct neigh_ops ndisc_hh_ops = { + .family = AF_INET6, + .solicit = ndisc_solicit, + .error_report = ndisc_error_report, + .output = neigh_resolve_output, + .connected_output = neigh_resolve_output, +}; + + +static const struct neigh_ops ndisc_direct_ops = { + .family = AF_INET6, + .output = neigh_direct_output, + .connected_output = neigh_direct_output, +}; + +struct neigh_table nd_tbl = { + .family = AF_INET6, + .key_len = sizeof(struct in6_addr), + .protocol = cpu_to_be16(ETH_P_IPV6), + .hash = ndisc_hash, + .key_eq = ndisc_key_eq, + .constructor = ndisc_constructor, + .pconstructor = pndisc_constructor, + .pdestructor = pndisc_destructor, + .proxy_redo = pndisc_redo, + .is_multicast = ndisc_is_multicast, + .allow_add = ndisc_allow_add, + .id = "ndisc_cache", + .parms = { + .tbl = &nd_tbl, + .reachable_time = ND_REACHABLE_TIME, + .data = { + [NEIGH_VAR_MCAST_PROBES] = 3, + [NEIGH_VAR_UCAST_PROBES] = 3, + [NEIGH_VAR_RETRANS_TIME] = ND_RETRANS_TIMER, + [NEIGH_VAR_BASE_REACHABLE_TIME] = ND_REACHABLE_TIME, + [NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ, + [NEIGH_VAR_INTERVAL_PROBE_TIME_MS] = 5 * HZ, + [NEIGH_VAR_GC_STALETIME] = 60 * HZ, + [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX, + [NEIGH_VAR_PROXY_QLEN] = 64, + [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ, + [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10, + }, + }, + .gc_interval = 30 * HZ, + .gc_thresh1 = 128, + .gc_thresh2 = 512, + .gc_thresh3 = 1024, +}; +EXPORT_SYMBOL_GPL(nd_tbl); + +void __ndisc_fill_addr_option(struct sk_buff *skb, int type, const void *data, + int data_len, int pad) +{ + int space = __ndisc_opt_addr_space(data_len, pad); + u8 *opt = skb_put(skb, space); + + opt[0] = type; + opt[1] = space>>3; + + memset(opt + 2, 0, pad); + opt += pad; + space -= pad; + + memcpy(opt+2, data, data_len); + data_len += 2; + opt += data_len; + space -= data_len; + if (space > 0) + memset(opt, 0, space); +} +EXPORT_SYMBOL_GPL(__ndisc_fill_addr_option); + +static inline void ndisc_fill_addr_option(struct sk_buff *skb, int type, + const void *data, u8 icmp6_type) +{ + __ndisc_fill_addr_option(skb, type, data, skb->dev->addr_len, + ndisc_addr_option_pad(skb->dev->type)); + ndisc_ops_fill_addr_option(skb->dev, skb, icmp6_type); +} + +static inline void ndisc_fill_redirect_addr_option(struct sk_buff *skb, + void *ha, + const u8 *ops_data) +{ + ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR, ha, NDISC_REDIRECT); + ndisc_ops_fill_redirect_addr_option(skb->dev, skb, ops_data); +} + +static struct nd_opt_hdr *ndisc_next_option(struct nd_opt_hdr *cur, + struct nd_opt_hdr *end) +{ + int type; + if (!cur || !end || cur >= end) + return NULL; + type = cur->nd_opt_type; + do { + cur = ((void *)cur) + (cur->nd_opt_len << 3); + } while (cur < end && cur->nd_opt_type != type); + return cur <= end && cur->nd_opt_type == type ? cur : NULL; +} + +static inline int ndisc_is_useropt(const struct net_device *dev, + struct nd_opt_hdr *opt) +{ + return opt->nd_opt_type == ND_OPT_PREFIX_INFO || + opt->nd_opt_type == ND_OPT_RDNSS || + opt->nd_opt_type == ND_OPT_DNSSL || + opt->nd_opt_type == ND_OPT_CAPTIVE_PORTAL || + opt->nd_opt_type == ND_OPT_PREF64 || + ndisc_ops_is_useropt(dev, opt->nd_opt_type); +} + +static struct nd_opt_hdr *ndisc_next_useropt(const struct net_device *dev, + struct nd_opt_hdr *cur, + struct nd_opt_hdr *end) +{ + if (!cur || !end || cur >= end) + return NULL; + do { + cur = ((void *)cur) + (cur->nd_opt_len << 3); + } while (cur < end && !ndisc_is_useropt(dev, cur)); + return cur <= end && ndisc_is_useropt(dev, cur) ? cur : NULL; +} + +struct ndisc_options *ndisc_parse_options(const struct net_device *dev, + u8 *opt, int opt_len, + struct ndisc_options *ndopts) +{ + struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)opt; + + if (!nd_opt || opt_len < 0 || !ndopts) + return NULL; + memset(ndopts, 0, sizeof(*ndopts)); + while (opt_len) { + int l; + if (opt_len < sizeof(struct nd_opt_hdr)) + return NULL; + l = nd_opt->nd_opt_len << 3; + if (opt_len < l || l == 0) + return NULL; + if (ndisc_ops_parse_options(dev, nd_opt, ndopts)) + goto next_opt; + switch (nd_opt->nd_opt_type) { + case ND_OPT_SOURCE_LL_ADDR: + case ND_OPT_TARGET_LL_ADDR: + case ND_OPT_MTU: + case ND_OPT_NONCE: + case ND_OPT_REDIRECT_HDR: + if (ndopts->nd_opt_array[nd_opt->nd_opt_type]) { + ND_PRINTK(2, warn, + "%s: duplicated ND6 option found: type=%d\n", + __func__, nd_opt->nd_opt_type); + } else { + ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt; + } + break; + case ND_OPT_PREFIX_INFO: + ndopts->nd_opts_pi_end = nd_opt; + if (!ndopts->nd_opt_array[nd_opt->nd_opt_type]) + ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt; + break; +#ifdef CONFIG_IPV6_ROUTE_INFO + case ND_OPT_ROUTE_INFO: + ndopts->nd_opts_ri_end = nd_opt; + if (!ndopts->nd_opts_ri) + ndopts->nd_opts_ri = nd_opt; + break; +#endif + default: + if (ndisc_is_useropt(dev, nd_opt)) { + ndopts->nd_useropts_end = nd_opt; + if (!ndopts->nd_useropts) + ndopts->nd_useropts = nd_opt; + } else { + /* + * Unknown options must be silently ignored, + * to accommodate future extension to the + * protocol. + */ + ND_PRINTK(2, notice, + "%s: ignored unsupported option; type=%d, len=%d\n", + __func__, + nd_opt->nd_opt_type, + nd_opt->nd_opt_len); + } + } +next_opt: + opt_len -= l; + nd_opt = ((void *)nd_opt) + l; + } + return ndopts; +} + +int ndisc_mc_map(const struct in6_addr *addr, char *buf, struct net_device *dev, int dir) +{ + switch (dev->type) { + case ARPHRD_ETHER: + case ARPHRD_IEEE802: /* Not sure. Check it later. --ANK */ + case ARPHRD_FDDI: + ipv6_eth_mc_map(addr, buf); + return 0; + case ARPHRD_ARCNET: + ipv6_arcnet_mc_map(addr, buf); + return 0; + case ARPHRD_INFINIBAND: + ipv6_ib_mc_map(addr, dev->broadcast, buf); + return 0; + case ARPHRD_IPGRE: + return ipv6_ipgre_mc_map(addr, dev->broadcast, buf); + default: + if (dir) { + memcpy(buf, dev->broadcast, dev->addr_len); + return 0; + } + } + return -EINVAL; +} +EXPORT_SYMBOL(ndisc_mc_map); + +static u32 ndisc_hash(const void *pkey, + const struct net_device *dev, + __u32 *hash_rnd) +{ + return ndisc_hashfn(pkey, dev, hash_rnd); +} + +static bool ndisc_key_eq(const struct neighbour *n, const void *pkey) +{ + return neigh_key_eq128(n, pkey); +} + +static int ndisc_constructor(struct neighbour *neigh) +{ + struct in6_addr *addr = (struct in6_addr *)&neigh->primary_key; + struct net_device *dev = neigh->dev; + struct inet6_dev *in6_dev; + struct neigh_parms *parms; + bool is_multicast = ipv6_addr_is_multicast(addr); + + in6_dev = in6_dev_get(dev); + if (!in6_dev) { + return -EINVAL; + } + + parms = in6_dev->nd_parms; + __neigh_parms_put(neigh->parms); + neigh->parms = neigh_parms_clone(parms); + + neigh->type = is_multicast ? RTN_MULTICAST : RTN_UNICAST; + if (!dev->header_ops) { + neigh->nud_state = NUD_NOARP; + neigh->ops = &ndisc_direct_ops; + neigh->output = neigh_direct_output; + } else { + if (is_multicast) { + neigh->nud_state = NUD_NOARP; + ndisc_mc_map(addr, neigh->ha, dev, 1); + } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) { + neigh->nud_state = NUD_NOARP; + memcpy(neigh->ha, dev->dev_addr, dev->addr_len); + if (dev->flags&IFF_LOOPBACK) + neigh->type = RTN_LOCAL; + } else if (dev->flags&IFF_POINTOPOINT) { + neigh->nud_state = NUD_NOARP; + memcpy(neigh->ha, dev->broadcast, dev->addr_len); + } + if (dev->header_ops->cache) + neigh->ops = &ndisc_hh_ops; + else + neigh->ops = &ndisc_generic_ops; + if (neigh->nud_state&NUD_VALID) + neigh->output = neigh->ops->connected_output; + else + neigh->output = neigh->ops->output; + } + in6_dev_put(in6_dev); + return 0; +} + +static int pndisc_constructor(struct pneigh_entry *n) +{ + struct in6_addr *addr = (struct in6_addr *)&n->key; + struct in6_addr maddr; + struct net_device *dev = n->dev; + + if (!dev || !__in6_dev_get(dev)) + return -EINVAL; + addrconf_addr_solict_mult(addr, &maddr); + ipv6_dev_mc_inc(dev, &maddr); + return 0; +} + +static void pndisc_destructor(struct pneigh_entry *n) +{ + struct in6_addr *addr = (struct in6_addr *)&n->key; + struct in6_addr maddr; + struct net_device *dev = n->dev; + + if (!dev || !__in6_dev_get(dev)) + return; + addrconf_addr_solict_mult(addr, &maddr); + ipv6_dev_mc_dec(dev, &maddr); +} + +/* called with rtnl held */ +static bool ndisc_allow_add(const struct net_device *dev, + struct netlink_ext_ack *extack) +{ + struct inet6_dev *idev = __in6_dev_get(dev); + + if (!idev || idev->cnf.disable_ipv6) { + NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device"); + return false; + } + + return true; +} + +static struct sk_buff *ndisc_alloc_skb(struct net_device *dev, + int len) +{ + int hlen = LL_RESERVED_SPACE(dev); + int tlen = dev->needed_tailroom; + struct sock *sk = dev_net(dev)->ipv6.ndisc_sk; + struct sk_buff *skb; + + skb = alloc_skb(hlen + sizeof(struct ipv6hdr) + len + tlen, GFP_ATOMIC); + if (!skb) { + ND_PRINTK(0, err, "ndisc: %s failed to allocate an skb\n", + __func__); + return NULL; + } + + skb->protocol = htons(ETH_P_IPV6); + skb->dev = dev; + + skb_reserve(skb, hlen + sizeof(struct ipv6hdr)); + skb_reset_transport_header(skb); + + /* Manually assign socket ownership as we avoid calling + * sock_alloc_send_pskb() to bypass wmem buffer limits + */ + skb_set_owner_w(skb, sk); + + return skb; +} + +static void ip6_nd_hdr(struct sk_buff *skb, + const struct in6_addr *saddr, + const struct in6_addr *daddr, + int hop_limit, int len) +{ + struct ipv6hdr *hdr; + struct inet6_dev *idev; + unsigned tclass; + + rcu_read_lock(); + idev = __in6_dev_get(skb->dev); + tclass = idev ? idev->cnf.ndisc_tclass : 0; + rcu_read_unlock(); + + skb_push(skb, sizeof(*hdr)); + skb_reset_network_header(skb); + hdr = ipv6_hdr(skb); + + ip6_flow_hdr(hdr, tclass, 0); + + hdr->payload_len = htons(len); + hdr->nexthdr = IPPROTO_ICMPV6; + hdr->hop_limit = hop_limit; + + hdr->saddr = *saddr; + hdr->daddr = *daddr; +} + +void ndisc_send_skb(struct sk_buff *skb, const struct in6_addr *daddr, + const struct in6_addr *saddr) +{ + struct dst_entry *dst = skb_dst(skb); + struct net *net = dev_net(skb->dev); + struct sock *sk = net->ipv6.ndisc_sk; + struct inet6_dev *idev; + int err; + struct icmp6hdr *icmp6h = icmp6_hdr(skb); + u8 type; + + type = icmp6h->icmp6_type; + + if (!dst) { + struct flowi6 fl6; + int oif = skb->dev->ifindex; + + icmpv6_flow_init(sk, &fl6, type, saddr, daddr, oif); + dst = icmp6_dst_alloc(skb->dev, &fl6); + if (IS_ERR(dst)) { + kfree_skb(skb); + return; + } + + skb_dst_set(skb, dst); + } + + icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, skb->len, + IPPROTO_ICMPV6, + csum_partial(icmp6h, + skb->len, 0)); + + ip6_nd_hdr(skb, saddr, daddr, inet6_sk(sk)->hop_limit, skb->len); + + rcu_read_lock(); + idev = __in6_dev_get(dst->dev); + IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len); + + err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, + net, sk, skb, NULL, dst->dev, + dst_output); + if (!err) { + ICMP6MSGOUT_INC_STATS(net, idev, type); + ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS); + } + + rcu_read_unlock(); +} +EXPORT_SYMBOL(ndisc_send_skb); + +void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr, + const struct in6_addr *solicited_addr, + bool router, bool solicited, bool override, bool inc_opt) +{ + struct sk_buff *skb; + struct in6_addr tmpaddr; + struct inet6_ifaddr *ifp; + const struct in6_addr *src_addr; + struct nd_msg *msg; + int optlen = 0; + + /* for anycast or proxy, solicited_addr != src_addr */ + ifp = ipv6_get_ifaddr(dev_net(dev), solicited_addr, dev, 1); + if (ifp) { + src_addr = solicited_addr; + if (ifp->flags & IFA_F_OPTIMISTIC) + override = false; + inc_opt |= ifp->idev->cnf.force_tllao; + in6_ifa_put(ifp); + } else { + if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr, + inet6_sk(dev_net(dev)->ipv6.ndisc_sk)->srcprefs, + &tmpaddr)) + return; + src_addr = &tmpaddr; + } + + if (!dev->addr_len) + inc_opt = false; + if (inc_opt) + optlen += ndisc_opt_addr_space(dev, + NDISC_NEIGHBOUR_ADVERTISEMENT); + + skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen); + if (!skb) + return; + + msg = skb_put(skb, sizeof(*msg)); + *msg = (struct nd_msg) { + .icmph = { + .icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT, + .icmp6_router = router, + .icmp6_solicited = solicited, + .icmp6_override = override, + }, + .target = *solicited_addr, + }; + + if (inc_opt) + ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR, + dev->dev_addr, + NDISC_NEIGHBOUR_ADVERTISEMENT); + + ndisc_send_skb(skb, daddr, src_addr); +} + +static void ndisc_send_unsol_na(struct net_device *dev) +{ + struct inet6_dev *idev; + struct inet6_ifaddr *ifa; + + idev = in6_dev_get(dev); + if (!idev) + return; + + read_lock_bh(&idev->lock); + list_for_each_entry(ifa, &idev->addr_list, if_list) { + /* skip tentative addresses until dad completes */ + if (ifa->flags & IFA_F_TENTATIVE && + !(ifa->flags & IFA_F_OPTIMISTIC)) + continue; + + ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifa->addr, + /*router=*/ !!idev->cnf.forwarding, + /*solicited=*/ false, /*override=*/ true, + /*inc_opt=*/ true); + } + read_unlock_bh(&idev->lock); + + in6_dev_put(idev); +} + +struct sk_buff *ndisc_ns_create(struct net_device *dev, const struct in6_addr *solicit, + const struct in6_addr *saddr, u64 nonce) +{ + int inc_opt = dev->addr_len; + struct sk_buff *skb; + struct nd_msg *msg; + int optlen = 0; + + if (!saddr) + return NULL; + + if (ipv6_addr_any(saddr)) + inc_opt = false; + if (inc_opt) + optlen += ndisc_opt_addr_space(dev, + NDISC_NEIGHBOUR_SOLICITATION); + if (nonce != 0) + optlen += 8; + + skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen); + if (!skb) + return NULL; + + msg = skb_put(skb, sizeof(*msg)); + *msg = (struct nd_msg) { + .icmph = { + .icmp6_type = NDISC_NEIGHBOUR_SOLICITATION, + }, + .target = *solicit, + }; + + if (inc_opt) + ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR, + dev->dev_addr, + NDISC_NEIGHBOUR_SOLICITATION); + if (nonce != 0) { + u8 *opt = skb_put(skb, 8); + + opt[0] = ND_OPT_NONCE; + opt[1] = 8 >> 3; + memcpy(opt + 2, &nonce, 6); + } + + return skb; +} +EXPORT_SYMBOL(ndisc_ns_create); + +void ndisc_send_ns(struct net_device *dev, const struct in6_addr *solicit, + const struct in6_addr *daddr, const struct in6_addr *saddr, + u64 nonce) +{ + struct in6_addr addr_buf; + struct sk_buff *skb; + + if (!saddr) { + if (ipv6_get_lladdr(dev, &addr_buf, + (IFA_F_TENTATIVE | IFA_F_OPTIMISTIC))) + return; + saddr = &addr_buf; + } + + skb = ndisc_ns_create(dev, solicit, saddr, nonce); + + if (skb) + ndisc_send_skb(skb, daddr, saddr); +} + +void ndisc_send_rs(struct net_device *dev, const struct in6_addr *saddr, + const struct in6_addr *daddr) +{ + struct sk_buff *skb; + struct rs_msg *msg; + int send_sllao = dev->addr_len; + int optlen = 0; + +#ifdef CONFIG_IPV6_OPTIMISTIC_DAD + /* + * According to section 2.2 of RFC 4429, we must not + * send router solicitations with a sllao from + * optimistic addresses, but we may send the solicitation + * if we don't include the sllao. So here we check + * if our address is optimistic, and if so, we + * suppress the inclusion of the sllao. + */ + if (send_sllao) { + struct inet6_ifaddr *ifp = ipv6_get_ifaddr(dev_net(dev), saddr, + dev, 1); + if (ifp) { + if (ifp->flags & IFA_F_OPTIMISTIC) { + send_sllao = 0; + } + in6_ifa_put(ifp); + } else { + send_sllao = 0; + } + } +#endif + if (send_sllao) + optlen += ndisc_opt_addr_space(dev, NDISC_ROUTER_SOLICITATION); + + skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen); + if (!skb) + return; + + msg = skb_put(skb, sizeof(*msg)); + *msg = (struct rs_msg) { + .icmph = { + .icmp6_type = NDISC_ROUTER_SOLICITATION, + }, + }; + + if (send_sllao) + ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR, + dev->dev_addr, + NDISC_ROUTER_SOLICITATION); + + ndisc_send_skb(skb, daddr, saddr); +} + + +static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb) +{ + /* + * "The sender MUST return an ICMP + * destination unreachable" + */ + dst_link_failure(skb); + kfree_skb(skb); +} + +/* Called with locked neigh: either read or both */ + +static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb) +{ + struct in6_addr *saddr = NULL; + struct in6_addr mcaddr; + struct net_device *dev = neigh->dev; + struct in6_addr *target = (struct in6_addr *)&neigh->primary_key; + int probes = atomic_read(&neigh->probes); + + if (skb && ipv6_chk_addr_and_flags(dev_net(dev), &ipv6_hdr(skb)->saddr, + dev, false, 1, + IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) + saddr = &ipv6_hdr(skb)->saddr; + probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); + if (probes < 0) { + if (!(READ_ONCE(neigh->nud_state) & NUD_VALID)) { + ND_PRINTK(1, dbg, + "%s: trying to ucast probe in NUD_INVALID: %pI6\n", + __func__, target); + } + ndisc_send_ns(dev, target, target, saddr, 0); + } else if ((probes -= NEIGH_VAR(neigh->parms, APP_PROBES)) < 0) { + neigh_app_ns(neigh); + } else { + addrconf_addr_solict_mult(target, &mcaddr); + ndisc_send_ns(dev, target, &mcaddr, saddr, 0); + } +} + +static int pndisc_is_router(const void *pkey, + struct net_device *dev) +{ + struct pneigh_entry *n; + int ret = -1; + + read_lock_bh(&nd_tbl.lock); + n = __pneigh_lookup(&nd_tbl, dev_net(dev), pkey, dev); + if (n) + ret = !!(n->flags & NTF_ROUTER); + read_unlock_bh(&nd_tbl.lock); + + return ret; +} + +void ndisc_update(const struct net_device *dev, struct neighbour *neigh, + const u8 *lladdr, u8 new, u32 flags, u8 icmp6_type, + struct ndisc_options *ndopts) +{ + neigh_update(neigh, lladdr, new, flags, 0); + /* report ndisc ops about neighbour update */ + ndisc_ops_update(dev, neigh, flags, icmp6_type, ndopts); +} + +static void ndisc_recv_ns(struct sk_buff *skb) +{ + struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb); + const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr; + const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr; + u8 *lladdr = NULL; + u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) + + offsetof(struct nd_msg, opt)); + struct ndisc_options ndopts; + struct net_device *dev = skb->dev; + struct inet6_ifaddr *ifp; + struct inet6_dev *idev = NULL; + struct neighbour *neigh; + int dad = ipv6_addr_any(saddr); + bool inc; + int is_router = -1; + u64 nonce = 0; + + if (skb->len < sizeof(struct nd_msg)) { + ND_PRINTK(2, warn, "NS: packet too short\n"); + return; + } + + if (ipv6_addr_is_multicast(&msg->target)) { + ND_PRINTK(2, warn, "NS: multicast target address\n"); + return; + } + + /* + * RFC2461 7.1.1: + * DAD has to be destined for solicited node multicast address. + */ + if (dad && !ipv6_addr_is_solict_mult(daddr)) { + ND_PRINTK(2, warn, "NS: bad DAD packet (wrong destination)\n"); + return; + } + + if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) { + ND_PRINTK(2, warn, "NS: invalid ND options\n"); + return; + } + + if (ndopts.nd_opts_src_lladdr) { + lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, dev); + if (!lladdr) { + ND_PRINTK(2, warn, + "NS: invalid link-layer address length\n"); + return; + } + + /* RFC2461 7.1.1: + * If the IP source address is the unspecified address, + * there MUST NOT be source link-layer address option + * in the message. + */ + if (dad) { + ND_PRINTK(2, warn, + "NS: bad DAD packet (link-layer address option)\n"); + return; + } + } + if (ndopts.nd_opts_nonce && ndopts.nd_opts_nonce->nd_opt_len == 1) + memcpy(&nonce, (u8 *)(ndopts.nd_opts_nonce + 1), 6); + + inc = ipv6_addr_is_multicast(daddr); + + ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1); + if (ifp) { +have_ifp: + if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) { + if (dad) { + if (nonce != 0 && ifp->dad_nonce == nonce) { + u8 *np = (u8 *)&nonce; + /* Matching nonce if looped back */ + ND_PRINTK(2, notice, + "%s: IPv6 DAD loopback for address %pI6c nonce %pM ignored\n", + ifp->idev->dev->name, + &ifp->addr, np); + goto out; + } + /* + * We are colliding with another node + * who is doing DAD + * so fail our DAD process + */ + addrconf_dad_failure(skb, ifp); + return; + } else { + /* + * This is not a dad solicitation. + * If we are an optimistic node, + * we should respond. + * Otherwise, we should ignore it. + */ + if (!(ifp->flags & IFA_F_OPTIMISTIC)) + goto out; + } + } + + idev = ifp->idev; + } else { + struct net *net = dev_net(dev); + + /* perhaps an address on the master device */ + if (netif_is_l3_slave(dev)) { + struct net_device *mdev; + + mdev = netdev_master_upper_dev_get_rcu(dev); + if (mdev) { + ifp = ipv6_get_ifaddr(net, &msg->target, mdev, 1); + if (ifp) + goto have_ifp; + } + } + + idev = in6_dev_get(dev); + if (!idev) { + /* XXX: count this drop? */ + return; + } + + if (ipv6_chk_acast_addr(net, dev, &msg->target) || + (idev->cnf.forwarding && + (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) && + (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) { + if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) && + skb->pkt_type != PACKET_HOST && + inc && + NEIGH_VAR(idev->nd_parms, PROXY_DELAY) != 0) { + /* + * for anycast or proxy, + * sender should delay its response + * by a random time between 0 and + * MAX_ANYCAST_DELAY_TIME seconds. + * (RFC2461) -- yoshfuji + */ + struct sk_buff *n = skb_clone(skb, GFP_ATOMIC); + if (n) + pneigh_enqueue(&nd_tbl, idev->nd_parms, n); + goto out; + } + } else + goto out; + } + + if (is_router < 0) + is_router = idev->cnf.forwarding; + + if (dad) { + ndisc_send_na(dev, &in6addr_linklocal_allnodes, &msg->target, + !!is_router, false, (ifp != NULL), true); + goto out; + } + + if (inc) + NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_mcast); + else + NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_ucast); + + /* + * update / create cache entry + * for the source address + */ + neigh = __neigh_lookup(&nd_tbl, saddr, dev, + !inc || lladdr || !dev->addr_len); + if (neigh) + ndisc_update(dev, neigh, lladdr, NUD_STALE, + NEIGH_UPDATE_F_WEAK_OVERRIDE| + NEIGH_UPDATE_F_OVERRIDE, + NDISC_NEIGHBOUR_SOLICITATION, &ndopts); + if (neigh || !dev->header_ops) { + ndisc_send_na(dev, saddr, &msg->target, !!is_router, + true, (ifp != NULL && inc), inc); + if (neigh) + neigh_release(neigh); + } + +out: + if (ifp) + in6_ifa_put(ifp); + else + in6_dev_put(idev); +} + +static int accept_untracked_na(struct net_device *dev, struct in6_addr *saddr) +{ + struct inet6_dev *idev = __in6_dev_get(dev); + + switch (idev->cnf.accept_untracked_na) { + case 0: /* Don't accept untracked na (absent in neighbor cache) */ + return 0; + case 1: /* Create new entries from na if currently untracked */ + return 1; + case 2: /* Create new entries from untracked na only if saddr is in the + * same subnet as an address configured on the interface that + * received the na + */ + return !!ipv6_chk_prefix(saddr, dev); + default: + return 0; + } +} + +static void ndisc_recv_na(struct sk_buff *skb) +{ + struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb); + struct in6_addr *saddr = &ipv6_hdr(skb)->saddr; + const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr; + u8 *lladdr = NULL; + u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) + + offsetof(struct nd_msg, opt)); + struct ndisc_options ndopts; + struct net_device *dev = skb->dev; + struct inet6_dev *idev = __in6_dev_get(dev); + struct inet6_ifaddr *ifp; + struct neighbour *neigh; + u8 new_state; + + if (skb->len < sizeof(struct nd_msg)) { + ND_PRINTK(2, warn, "NA: packet too short\n"); + return; + } + + if (ipv6_addr_is_multicast(&msg->target)) { + ND_PRINTK(2, warn, "NA: target address is multicast\n"); + return; + } + + if (ipv6_addr_is_multicast(daddr) && + msg->icmph.icmp6_solicited) { + ND_PRINTK(2, warn, "NA: solicited NA is multicasted\n"); + return; + } + + /* For some 802.11 wireless deployments (and possibly other networks), + * there will be a NA proxy and unsolicitd packets are attacks + * and thus should not be accepted. + * drop_unsolicited_na takes precedence over accept_untracked_na + */ + if (!msg->icmph.icmp6_solicited && idev && + idev->cnf.drop_unsolicited_na) + return; + + if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) { + ND_PRINTK(2, warn, "NS: invalid ND option\n"); + return; + } + if (ndopts.nd_opts_tgt_lladdr) { + lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr, dev); + if (!lladdr) { + ND_PRINTK(2, warn, + "NA: invalid link-layer address length\n"); + return; + } + } + ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1); + if (ifp) { + if (skb->pkt_type != PACKET_LOOPBACK + && (ifp->flags & IFA_F_TENTATIVE)) { + addrconf_dad_failure(skb, ifp); + return; + } + /* What should we make now? The advertisement + is invalid, but ndisc specs say nothing + about it. It could be misconfiguration, or + an smart proxy agent tries to help us :-) + + We should not print the error if NA has been + received from loopback - it is just our own + unsolicited advertisement. + */ + if (skb->pkt_type != PACKET_LOOPBACK) + ND_PRINTK(1, warn, + "NA: %pM advertised our address %pI6c on %s!\n", + eth_hdr(skb)->h_source, &ifp->addr, ifp->idev->dev->name); + in6_ifa_put(ifp); + return; + } + + neigh = neigh_lookup(&nd_tbl, &msg->target, dev); + + /* RFC 9131 updates original Neighbour Discovery RFC 4861. + * NAs with Target LL Address option without a corresponding + * entry in the neighbour cache can now create a STALE neighbour + * cache entry on routers. + * + * entry accept fwding solicited behaviour + * ------- ------ ------ --------- ---------------------- + * present X X 0 Set state to STALE + * present X X 1 Set state to REACHABLE + * absent 0 X X Do nothing + * absent 1 0 X Do nothing + * absent 1 1 X Add a new STALE entry + * + * Note that we don't do a (daddr == all-routers-mcast) check. + */ + new_state = msg->icmph.icmp6_solicited ? NUD_REACHABLE : NUD_STALE; + if (!neigh && lladdr && idev && idev->cnf.forwarding) { + if (accept_untracked_na(dev, saddr)) { + neigh = neigh_create(&nd_tbl, &msg->target, dev); + new_state = NUD_STALE; + } + } + + if (neigh && !IS_ERR(neigh)) { + u8 old_flags = neigh->flags; + struct net *net = dev_net(dev); + + if (READ_ONCE(neigh->nud_state) & NUD_FAILED) + goto out; + + /* + * Don't update the neighbor cache entry on a proxy NA from + * ourselves because either the proxied node is off link or it + * has already sent a NA to us. + */ + if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) && + net->ipv6.devconf_all->forwarding && net->ipv6.devconf_all->proxy_ndp && + pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) { + /* XXX: idev->cnf.proxy_ndp */ + goto out; + } + + ndisc_update(dev, neigh, lladdr, + new_state, + NEIGH_UPDATE_F_WEAK_OVERRIDE| + (msg->icmph.icmp6_override ? NEIGH_UPDATE_F_OVERRIDE : 0)| + NEIGH_UPDATE_F_OVERRIDE_ISROUTER| + (msg->icmph.icmp6_router ? NEIGH_UPDATE_F_ISROUTER : 0), + NDISC_NEIGHBOUR_ADVERTISEMENT, &ndopts); + + if ((old_flags & ~neigh->flags) & NTF_ROUTER) { + /* + * Change: router to host + */ + rt6_clean_tohost(dev_net(dev), saddr); + } + +out: + neigh_release(neigh); + } +} + +static void ndisc_recv_rs(struct sk_buff *skb) +{ + struct rs_msg *rs_msg = (struct rs_msg *)skb_transport_header(skb); + unsigned long ndoptlen = skb->len - sizeof(*rs_msg); + struct neighbour *neigh; + struct inet6_dev *idev; + const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr; + struct ndisc_options ndopts; + u8 *lladdr = NULL; + + if (skb->len < sizeof(*rs_msg)) + return; + + idev = __in6_dev_get(skb->dev); + if (!idev) { + ND_PRINTK(1, err, "RS: can't find in6 device\n"); + return; + } + + /* Don't accept RS if we're not in router mode */ + if (!idev->cnf.forwarding) + goto out; + + /* + * Don't update NCE if src = ::; + * this implies that the source node has no ip address assigned yet. + */ + if (ipv6_addr_any(saddr)) + goto out; + + /* Parse ND options */ + if (!ndisc_parse_options(skb->dev, rs_msg->opt, ndoptlen, &ndopts)) { + ND_PRINTK(2, notice, "NS: invalid ND option, ignored\n"); + goto out; + } + + if (ndopts.nd_opts_src_lladdr) { + lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, + skb->dev); + if (!lladdr) + goto out; + } + + neigh = __neigh_lookup(&nd_tbl, saddr, skb->dev, 1); + if (neigh) { + ndisc_update(skb->dev, neigh, lladdr, NUD_STALE, + NEIGH_UPDATE_F_WEAK_OVERRIDE| + NEIGH_UPDATE_F_OVERRIDE| + NEIGH_UPDATE_F_OVERRIDE_ISROUTER, + NDISC_ROUTER_SOLICITATION, &ndopts); + neigh_release(neigh); + } +out: + return; +} + +static void ndisc_ra_useropt(struct sk_buff *ra, struct nd_opt_hdr *opt) +{ + struct icmp6hdr *icmp6h = (struct icmp6hdr *)skb_transport_header(ra); + struct sk_buff *skb; + struct nlmsghdr *nlh; + struct nduseroptmsg *ndmsg; + struct net *net = dev_net(ra->dev); + int err; + int base_size = NLMSG_ALIGN(sizeof(struct nduseroptmsg) + + (opt->nd_opt_len << 3)); + size_t msg_size = base_size + nla_total_size(sizeof(struct in6_addr)); + + skb = nlmsg_new(msg_size, GFP_ATOMIC); + if (!skb) { + err = -ENOBUFS; + goto errout; + } + + nlh = nlmsg_put(skb, 0, 0, RTM_NEWNDUSEROPT, base_size, 0); + if (!nlh) { + goto nla_put_failure; + } + + ndmsg = nlmsg_data(nlh); + ndmsg->nduseropt_family = AF_INET6; + ndmsg->nduseropt_ifindex = ra->dev->ifindex; + ndmsg->nduseropt_icmp_type = icmp6h->icmp6_type; + ndmsg->nduseropt_icmp_code = icmp6h->icmp6_code; + ndmsg->nduseropt_opts_len = opt->nd_opt_len << 3; + + memcpy(ndmsg + 1, opt, opt->nd_opt_len << 3); + + if (nla_put_in6_addr(skb, NDUSEROPT_SRCADDR, &ipv6_hdr(ra)->saddr)) + goto nla_put_failure; + nlmsg_end(skb, nlh); + + rtnl_notify(skb, net, 0, RTNLGRP_ND_USEROPT, NULL, GFP_ATOMIC); + return; + +nla_put_failure: + nlmsg_free(skb); + err = -EMSGSIZE; +errout: + rtnl_set_sk_err(net, RTNLGRP_ND_USEROPT, err); +} + +static void ndisc_router_discovery(struct sk_buff *skb) +{ + struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb); + struct neighbour *neigh = NULL; + struct inet6_dev *in6_dev; + struct fib6_info *rt = NULL; + u32 defrtr_usr_metric; + struct net *net; + int lifetime; + struct ndisc_options ndopts; + int optlen; + unsigned int pref = 0; + __u32 old_if_flags; + bool send_ifinfo_notify = false; + + __u8 *opt = (__u8 *)(ra_msg + 1); + + optlen = (skb_tail_pointer(skb) - skb_transport_header(skb)) - + sizeof(struct ra_msg); + + ND_PRINTK(2, info, + "RA: %s, dev: %s\n", + __func__, skb->dev->name); + if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) { + ND_PRINTK(2, warn, "RA: source address is not link-local\n"); + return; + } + if (optlen < 0) { + ND_PRINTK(2, warn, "RA: packet too short\n"); + return; + } + +#ifdef CONFIG_IPV6_NDISC_NODETYPE + if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) { + ND_PRINTK(2, warn, "RA: from host or unauthorized router\n"); + return; + } +#endif + + /* + * set the RA_RECV flag in the interface + */ + + in6_dev = __in6_dev_get(skb->dev); + if (!in6_dev) { + ND_PRINTK(0, err, "RA: can't find inet6 device for %s\n", + skb->dev->name); + return; + } + + if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts)) { + ND_PRINTK(2, warn, "RA: invalid ND options\n"); + return; + } + + if (!ipv6_accept_ra(in6_dev)) { + ND_PRINTK(2, info, + "RA: %s, did not accept ra for dev: %s\n", + __func__, skb->dev->name); + goto skip_linkparms; + } + +#ifdef CONFIG_IPV6_NDISC_NODETYPE + /* skip link-specific parameters from interior routers */ + if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) { + ND_PRINTK(2, info, + "RA: %s, nodetype is NODEFAULT, dev: %s\n", + __func__, skb->dev->name); + goto skip_linkparms; + } +#endif + + if (in6_dev->if_flags & IF_RS_SENT) { + /* + * flag that an RA was received after an RS was sent + * out on this interface. + */ + in6_dev->if_flags |= IF_RA_RCVD; + } + + /* + * Remember the managed/otherconf flags from most recently + * received RA message (RFC 2462) -- yoshfuji + */ + old_if_flags = in6_dev->if_flags; + in6_dev->if_flags = (in6_dev->if_flags & ~(IF_RA_MANAGED | + IF_RA_OTHERCONF)) | + (ra_msg->icmph.icmp6_addrconf_managed ? + IF_RA_MANAGED : 0) | + (ra_msg->icmph.icmp6_addrconf_other ? + IF_RA_OTHERCONF : 0); + + if (old_if_flags != in6_dev->if_flags) + send_ifinfo_notify = true; + + if (!in6_dev->cnf.accept_ra_defrtr) { + ND_PRINTK(2, info, + "RA: %s, defrtr is false for dev: %s\n", + __func__, skb->dev->name); + goto skip_defrtr; + } + + lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime); + if (lifetime != 0 && lifetime < in6_dev->cnf.accept_ra_min_lft) { + ND_PRINTK(2, info, + "RA: router lifetime (%ds) is too short: %s\n", + lifetime, skb->dev->name); + goto skip_defrtr; + } + + /* Do not accept RA with source-addr found on local machine unless + * accept_ra_from_local is set to true. + */ + net = dev_net(in6_dev->dev); + if (!in6_dev->cnf.accept_ra_from_local && + ipv6_chk_addr(net, &ipv6_hdr(skb)->saddr, in6_dev->dev, 0)) { + ND_PRINTK(2, info, + "RA from local address detected on dev: %s: default router ignored\n", + skb->dev->name); + goto skip_defrtr; + } + +#ifdef CONFIG_IPV6_ROUTER_PREF + pref = ra_msg->icmph.icmp6_router_pref; + /* 10b is handled as if it were 00b (medium) */ + if (pref == ICMPV6_ROUTER_PREF_INVALID || + !in6_dev->cnf.accept_ra_rtr_pref) + pref = ICMPV6_ROUTER_PREF_MEDIUM; +#endif + /* routes added from RAs do not use nexthop objects */ + rt = rt6_get_dflt_router(net, &ipv6_hdr(skb)->saddr, skb->dev); + if (rt) { + neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6, + rt->fib6_nh->fib_nh_dev, NULL, + &ipv6_hdr(skb)->saddr); + if (!neigh) { + ND_PRINTK(0, err, + "RA: %s got default router without neighbour\n", + __func__); + fib6_info_release(rt); + return; + } + } + /* Set default route metric as specified by user */ + defrtr_usr_metric = in6_dev->cnf.ra_defrtr_metric; + /* delete the route if lifetime is 0 or if metric needs change */ + if (rt && (lifetime == 0 || rt->fib6_metric != defrtr_usr_metric)) { + ip6_del_rt(net, rt, false); + rt = NULL; + } + + ND_PRINTK(3, info, "RA: rt: %p lifetime: %d, metric: %d, for dev: %s\n", + rt, lifetime, defrtr_usr_metric, skb->dev->name); + if (!rt && lifetime) { + ND_PRINTK(3, info, "RA: adding default router\n"); + + if (neigh) + neigh_release(neigh); + + rt = rt6_add_dflt_router(net, &ipv6_hdr(skb)->saddr, + skb->dev, pref, defrtr_usr_metric); + if (!rt) { + ND_PRINTK(0, err, + "RA: %s failed to add default route\n", + __func__); + return; + } + + neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6, + rt->fib6_nh->fib_nh_dev, NULL, + &ipv6_hdr(skb)->saddr); + if (!neigh) { + ND_PRINTK(0, err, + "RA: %s got default router without neighbour\n", + __func__); + fib6_info_release(rt); + return; + } + neigh->flags |= NTF_ROUTER; + } else if (rt && IPV6_EXTRACT_PREF(rt->fib6_flags) != pref) { + struct nl_info nlinfo = { + .nl_net = net, + }; + rt->fib6_flags = (rt->fib6_flags & ~RTF_PREF_MASK) | RTF_PREF(pref); + inet6_rt_notify(RTM_NEWROUTE, rt, &nlinfo, NLM_F_REPLACE); + } + + if (rt) + fib6_set_expires(rt, jiffies + (HZ * lifetime)); + if (in6_dev->cnf.accept_ra_min_hop_limit < 256 && + ra_msg->icmph.icmp6_hop_limit) { + if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) { + in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit; + fib6_metric_set(rt, RTAX_HOPLIMIT, + ra_msg->icmph.icmp6_hop_limit); + } else { + ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than minimum\n"); + } + } + +skip_defrtr: + + /* + * Update Reachable Time and Retrans Timer + */ + + if (in6_dev->nd_parms) { + unsigned long rtime = ntohl(ra_msg->retrans_timer); + + if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/HZ) { + rtime = (rtime*HZ)/1000; + if (rtime < HZ/100) + rtime = HZ/100; + NEIGH_VAR_SET(in6_dev->nd_parms, RETRANS_TIME, rtime); + in6_dev->tstamp = jiffies; + send_ifinfo_notify = true; + } + + rtime = ntohl(ra_msg->reachable_time); + if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/(3*HZ)) { + rtime = (rtime*HZ)/1000; + + if (rtime < HZ/10) + rtime = HZ/10; + + if (rtime != NEIGH_VAR(in6_dev->nd_parms, BASE_REACHABLE_TIME)) { + NEIGH_VAR_SET(in6_dev->nd_parms, + BASE_REACHABLE_TIME, rtime); + NEIGH_VAR_SET(in6_dev->nd_parms, + GC_STALETIME, 3 * rtime); + in6_dev->nd_parms->reachable_time = neigh_rand_reach_time(rtime); + in6_dev->tstamp = jiffies; + send_ifinfo_notify = true; + } + } + } + +skip_linkparms: + + /* + * Process options. + */ + + if (!neigh) + neigh = __neigh_lookup(&nd_tbl, &ipv6_hdr(skb)->saddr, + skb->dev, 1); + if (neigh) { + u8 *lladdr = NULL; + if (ndopts.nd_opts_src_lladdr) { + lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, + skb->dev); + if (!lladdr) { + ND_PRINTK(2, warn, + "RA: invalid link-layer address length\n"); + goto out; + } + } + ndisc_update(skb->dev, neigh, lladdr, NUD_STALE, + NEIGH_UPDATE_F_WEAK_OVERRIDE| + NEIGH_UPDATE_F_OVERRIDE| + NEIGH_UPDATE_F_OVERRIDE_ISROUTER| + NEIGH_UPDATE_F_ISROUTER, + NDISC_ROUTER_ADVERTISEMENT, &ndopts); + } + + if (!ipv6_accept_ra(in6_dev)) { + ND_PRINTK(2, info, + "RA: %s, accept_ra is false for dev: %s\n", + __func__, skb->dev->name); + goto out; + } + +#ifdef CONFIG_IPV6_ROUTE_INFO + if (!in6_dev->cnf.accept_ra_from_local && + ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr, + in6_dev->dev, 0)) { + ND_PRINTK(2, info, + "RA from local address detected on dev: %s: router info ignored.\n", + skb->dev->name); + goto skip_routeinfo; + } + + if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) { + struct nd_opt_hdr *p; + for (p = ndopts.nd_opts_ri; + p; + p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) { + struct route_info *ri = (struct route_info *)p; +#ifdef CONFIG_IPV6_NDISC_NODETYPE + if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT && + ri->prefix_len == 0) + continue; +#endif + if (ri->prefix_len == 0 && + !in6_dev->cnf.accept_ra_defrtr) + continue; + if (ri->lifetime != 0 && + ntohl(ri->lifetime) < in6_dev->cnf.accept_ra_min_lft) + continue; + if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen) + continue; + if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen) + continue; + rt6_route_rcv(skb->dev, (u8 *)p, (p->nd_opt_len) << 3, + &ipv6_hdr(skb)->saddr); + } + } + +skip_routeinfo: +#endif + +#ifdef CONFIG_IPV6_NDISC_NODETYPE + /* skip link-specific ndopts from interior routers */ + if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) { + ND_PRINTK(2, info, + "RA: %s, nodetype is NODEFAULT (interior routes), dev: %s\n", + __func__, skb->dev->name); + goto out; + } +#endif + + if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) { + struct nd_opt_hdr *p; + for (p = ndopts.nd_opts_pi; + p; + p = ndisc_next_option(p, ndopts.nd_opts_pi_end)) { + addrconf_prefix_rcv(skb->dev, (u8 *)p, + (p->nd_opt_len) << 3, + ndopts.nd_opts_src_lladdr != NULL); + } + } + + if (ndopts.nd_opts_mtu && in6_dev->cnf.accept_ra_mtu) { + __be32 n; + u32 mtu; + + memcpy(&n, ((u8 *)(ndopts.nd_opts_mtu+1))+2, sizeof(mtu)); + mtu = ntohl(n); + + if (in6_dev->ra_mtu != mtu) { + in6_dev->ra_mtu = mtu; + send_ifinfo_notify = true; + } + + if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) { + ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu); + } else if (in6_dev->cnf.mtu6 != mtu) { + in6_dev->cnf.mtu6 = mtu; + fib6_metric_set(rt, RTAX_MTU, mtu); + rt6_mtu_change(skb->dev, mtu); + } + } + + if (ndopts.nd_useropts) { + struct nd_opt_hdr *p; + for (p = ndopts.nd_useropts; + p; + p = ndisc_next_useropt(skb->dev, p, + ndopts.nd_useropts_end)) { + ndisc_ra_useropt(skb, p); + } + } + + if (ndopts.nd_opts_tgt_lladdr || ndopts.nd_opts_rh) { + ND_PRINTK(2, warn, "RA: invalid RA options\n"); + } +out: + /* Send a notify if RA changed managed/otherconf flags or + * timer settings or ra_mtu value + */ + if (send_ifinfo_notify) + inet6_ifinfo_notify(RTM_NEWLINK, in6_dev); + + fib6_info_release(rt); + if (neigh) + neigh_release(neigh); +} + +static void ndisc_redirect_rcv(struct sk_buff *skb) +{ + u8 *hdr; + struct ndisc_options ndopts; + struct rd_msg *msg = (struct rd_msg *)skb_transport_header(skb); + u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) + + offsetof(struct rd_msg, opt)); + +#ifdef CONFIG_IPV6_NDISC_NODETYPE + switch (skb->ndisc_nodetype) { + case NDISC_NODETYPE_HOST: + case NDISC_NODETYPE_NODEFAULT: + ND_PRINTK(2, warn, + "Redirect: from host or unauthorized router\n"); + return; + } +#endif + + if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) { + ND_PRINTK(2, warn, + "Redirect: source address is not link-local\n"); + return; + } + + if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts)) + return; + + if (!ndopts.nd_opts_rh) { + ip6_redirect_no_header(skb, dev_net(skb->dev), + skb->dev->ifindex); + return; + } + + hdr = (u8 *)ndopts.nd_opts_rh; + hdr += 8; + if (!pskb_pull(skb, hdr - skb_transport_header(skb))) + return; + + icmpv6_notify(skb, NDISC_REDIRECT, 0, 0); +} + +static void ndisc_fill_redirect_hdr_option(struct sk_buff *skb, + struct sk_buff *orig_skb, + int rd_len) +{ + u8 *opt = skb_put(skb, rd_len); + + memset(opt, 0, 8); + *(opt++) = ND_OPT_REDIRECT_HDR; + *(opt++) = (rd_len >> 3); + opt += 6; + + skb_copy_bits(orig_skb, skb_network_offset(orig_skb), opt, + rd_len - 8); +} + +void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target) +{ + struct net_device *dev = skb->dev; + struct net *net = dev_net(dev); + struct sock *sk = net->ipv6.ndisc_sk; + int optlen = 0; + struct inet_peer *peer; + struct sk_buff *buff; + struct rd_msg *msg; + struct in6_addr saddr_buf; + struct rt6_info *rt; + struct dst_entry *dst; + struct flowi6 fl6; + int rd_len; + u8 ha_buf[MAX_ADDR_LEN], *ha = NULL, + ops_data_buf[NDISC_OPS_REDIRECT_DATA_SPACE], *ops_data = NULL; + bool ret; + + if (netif_is_l3_master(skb->dev)) { + dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif); + if (!dev) + return; + } + + if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) { + ND_PRINTK(2, warn, "Redirect: no link-local address on %s\n", + dev->name); + return; + } + + if (!ipv6_addr_equal(&ipv6_hdr(skb)->daddr, target) && + ipv6_addr_type(target) != (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) { + ND_PRINTK(2, warn, + "Redirect: target address is not link-local unicast\n"); + return; + } + + icmpv6_flow_init(sk, &fl6, NDISC_REDIRECT, + &saddr_buf, &ipv6_hdr(skb)->saddr, dev->ifindex); + + dst = ip6_route_output(net, NULL, &fl6); + if (dst->error) { + dst_release(dst); + return; + } + dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0); + if (IS_ERR(dst)) + return; + + rt = (struct rt6_info *) dst; + + if (rt->rt6i_flags & RTF_GATEWAY) { + ND_PRINTK(2, warn, + "Redirect: destination is not a neighbour\n"); + goto release; + } + peer = inet_getpeer_v6(net->ipv6.peers, &ipv6_hdr(skb)->saddr, 1); + ret = inet_peer_xrlim_allow(peer, 1*HZ); + if (peer) + inet_putpeer(peer); + if (!ret) + goto release; + + if (dev->addr_len) { + struct neighbour *neigh = dst_neigh_lookup(skb_dst(skb), target); + if (!neigh) { + ND_PRINTK(2, warn, + "Redirect: no neigh for target address\n"); + goto release; + } + + read_lock_bh(&neigh->lock); + if (neigh->nud_state & NUD_VALID) { + memcpy(ha_buf, neigh->ha, dev->addr_len); + read_unlock_bh(&neigh->lock); + ha = ha_buf; + optlen += ndisc_redirect_opt_addr_space(dev, neigh, + ops_data_buf, + &ops_data); + } else + read_unlock_bh(&neigh->lock); + + neigh_release(neigh); + } + + rd_len = min_t(unsigned int, + IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(*msg) - optlen, + skb->len + 8); + rd_len &= ~0x7; + optlen += rd_len; + + buff = ndisc_alloc_skb(dev, sizeof(*msg) + optlen); + if (!buff) + goto release; + + msg = skb_put(buff, sizeof(*msg)); + *msg = (struct rd_msg) { + .icmph = { + .icmp6_type = NDISC_REDIRECT, + }, + .target = *target, + .dest = ipv6_hdr(skb)->daddr, + }; + + /* + * include target_address option + */ + + if (ha) + ndisc_fill_redirect_addr_option(buff, ha, ops_data); + + /* + * build redirect option and copy skb over to the new packet. + */ + + if (rd_len) + ndisc_fill_redirect_hdr_option(buff, skb, rd_len); + + skb_dst_set(buff, dst); + ndisc_send_skb(buff, &ipv6_hdr(skb)->saddr, &saddr_buf); + return; + +release: + dst_release(dst); +} + +static void pndisc_redo(struct sk_buff *skb) +{ + ndisc_recv_ns(skb); + kfree_skb(skb); +} + +static int ndisc_is_multicast(const void *pkey) +{ + return ipv6_addr_is_multicast((struct in6_addr *)pkey); +} + +static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb) +{ + struct inet6_dev *idev = __in6_dev_get(skb->dev); + + if (!idev) + return true; + if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED && + idev->cnf.suppress_frag_ndisc) { + net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n"); + return true; + } + return false; +} + +int ndisc_rcv(struct sk_buff *skb) +{ + struct nd_msg *msg; + + if (ndisc_suppress_frag_ndisc(skb)) + return 0; + + if (skb_linearize(skb)) + return 0; + + msg = (struct nd_msg *)skb_transport_header(skb); + + __skb_push(skb, skb->data - skb_transport_header(skb)); + + if (ipv6_hdr(skb)->hop_limit != 255) { + ND_PRINTK(2, warn, "NDISC: invalid hop-limit: %d\n", + ipv6_hdr(skb)->hop_limit); + return 0; + } + + if (msg->icmph.icmp6_code != 0) { + ND_PRINTK(2, warn, "NDISC: invalid ICMPv6 code: %d\n", + msg->icmph.icmp6_code); + return 0; + } + + switch (msg->icmph.icmp6_type) { + case NDISC_NEIGHBOUR_SOLICITATION: + memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); + ndisc_recv_ns(skb); + break; + + case NDISC_NEIGHBOUR_ADVERTISEMENT: + ndisc_recv_na(skb); + break; + + case NDISC_ROUTER_SOLICITATION: + ndisc_recv_rs(skb); + break; + + case NDISC_ROUTER_ADVERTISEMENT: + ndisc_router_discovery(skb); + break; + + case NDISC_REDIRECT: + ndisc_redirect_rcv(skb); + break; + } + + return 0; +} + +static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) +{ + struct net_device *dev = netdev_notifier_info_to_dev(ptr); + struct netdev_notifier_change_info *change_info; + struct net *net = dev_net(dev); + struct inet6_dev *idev; + bool evict_nocarrier; + + switch (event) { + case NETDEV_CHANGEADDR: + neigh_changeaddr(&nd_tbl, dev); + fib6_run_gc(0, net, false); + fallthrough; + case NETDEV_UP: + idev = in6_dev_get(dev); + if (!idev) + break; + if (idev->cnf.ndisc_notify || + net->ipv6.devconf_all->ndisc_notify) + ndisc_send_unsol_na(dev); + in6_dev_put(idev); + break; + case NETDEV_CHANGE: + idev = in6_dev_get(dev); + if (!idev) + evict_nocarrier = true; + else { + evict_nocarrier = idev->cnf.ndisc_evict_nocarrier && + net->ipv6.devconf_all->ndisc_evict_nocarrier; + in6_dev_put(idev); + } + + change_info = ptr; + if (change_info->flags_changed & IFF_NOARP) + neigh_changeaddr(&nd_tbl, dev); + if (evict_nocarrier && !netif_carrier_ok(dev)) + neigh_carrier_down(&nd_tbl, dev); + break; + case NETDEV_DOWN: + neigh_ifdown(&nd_tbl, dev); + fib6_run_gc(0, net, false); + break; + case NETDEV_NOTIFY_PEERS: + ndisc_send_unsol_na(dev); + break; + default: + break; + } + + return NOTIFY_DONE; +} + +static struct notifier_block ndisc_netdev_notifier = { + .notifier_call = ndisc_netdev_event, + .priority = ADDRCONF_NOTIFY_PRIORITY - 5, +}; + +#ifdef CONFIG_SYSCTL +static void ndisc_warn_deprecated_sysctl(struct ctl_table *ctl, + const char *func, const char *dev_name) +{ + static char warncomm[TASK_COMM_LEN]; + static int warned; + if (strcmp(warncomm, current->comm) && warned < 5) { + strcpy(warncomm, current->comm); + pr_warn("process `%s' is using deprecated sysctl (%s) net.ipv6.neigh.%s.%s - use net.ipv6.neigh.%s.%s_ms instead\n", + warncomm, func, + dev_name, ctl->procname, + dev_name, ctl->procname); + warned++; + } +} + +int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void *buffer, + size_t *lenp, loff_t *ppos) +{ + struct net_device *dev = ctl->extra1; + struct inet6_dev *idev; + int ret; + + if ((strcmp(ctl->procname, "retrans_time") == 0) || + (strcmp(ctl->procname, "base_reachable_time") == 0)) + ndisc_warn_deprecated_sysctl(ctl, "syscall", dev ? dev->name : "default"); + + if (strcmp(ctl->procname, "retrans_time") == 0) + ret = neigh_proc_dointvec(ctl, write, buffer, lenp, ppos); + + else if (strcmp(ctl->procname, "base_reachable_time") == 0) + ret = neigh_proc_dointvec_jiffies(ctl, write, + buffer, lenp, ppos); + + else if ((strcmp(ctl->procname, "retrans_time_ms") == 0) || + (strcmp(ctl->procname, "base_reachable_time_ms") == 0)) + ret = neigh_proc_dointvec_ms_jiffies(ctl, write, + buffer, lenp, ppos); + else + ret = -1; + + if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) { + if (ctl->data == &NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME)) + idev->nd_parms->reachable_time = + neigh_rand_reach_time(NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME)); + idev->tstamp = jiffies; + inet6_ifinfo_notify(RTM_NEWLINK, idev); + in6_dev_put(idev); + } + return ret; +} + + +#endif + +static int __net_init ndisc_net_init(struct net *net) +{ + struct ipv6_pinfo *np; + struct sock *sk; + int err; + + err = inet_ctl_sock_create(&sk, PF_INET6, + SOCK_RAW, IPPROTO_ICMPV6, net); + if (err < 0) { + ND_PRINTK(0, err, + "NDISC: Failed to initialize the control socket (err %d)\n", + err); + return err; + } + + net->ipv6.ndisc_sk = sk; + + np = inet6_sk(sk); + np->hop_limit = 255; + /* Do not loopback ndisc messages */ + np->mc_loop = 0; + + return 0; +} + +static void __net_exit ndisc_net_exit(struct net *net) +{ + inet_ctl_sock_destroy(net->ipv6.ndisc_sk); +} + +static struct pernet_operations ndisc_net_ops = { + .init = ndisc_net_init, + .exit = ndisc_net_exit, +}; + +int __init ndisc_init(void) +{ + int err; + + err = register_pernet_subsys(&ndisc_net_ops); + if (err) + return err; + /* + * Initialize the neighbour table + */ + neigh_table_init(NEIGH_ND_TABLE, &nd_tbl); + +#ifdef CONFIG_SYSCTL + err = neigh_sysctl_register(NULL, &nd_tbl.parms, + ndisc_ifinfo_sysctl_change); + if (err) + goto out_unregister_pernet; +out: +#endif + return err; + +#ifdef CONFIG_SYSCTL +out_unregister_pernet: + unregister_pernet_subsys(&ndisc_net_ops); + goto out; +#endif +} + +int __init ndisc_late_init(void) +{ + return register_netdevice_notifier(&ndisc_netdev_notifier); +} + +void ndisc_late_cleanup(void) +{ + unregister_netdevice_notifier(&ndisc_netdev_notifier); +} + +void ndisc_cleanup(void) +{ +#ifdef CONFIG_SYSCTL + neigh_sysctl_unregister(&nd_tbl.parms); +#endif + neigh_table_clear(NEIGH_ND_TABLE, &nd_tbl); + unregister_pernet_subsys(&ndisc_net_ops); +} |