// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Neighbour Discovery for IPv6
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <[email protected]>
* Mike Shaver <[email protected]>
*/
/*
* 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_6CO ||
opt->nd_opt_type == ND_OPT_CAPTIVE_PORTAL ||
opt->nd_opt_type == ND_OPT_PREF64;
}
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) {
bool unknown = false;
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:
unknown = true;
}
if (ndisc_is_useropt(dev, nd_opt)) {
ndopts->nd_useropts_end = nd_opt;
if (!ndopts->nd_useropts)
ndopts->nd_useropts = nd_opt;
} else if (unknown) {
/*
* 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 ? READ_ONCE(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, READ_ONCE(inet6_sk(sk)->hop_limit), skb->len);
rcu_read_lock();
idev = __in6_dev_get(dst->dev);
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS);
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 |= READ_ONCE(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 enum skb_drop_reason 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);
int is_router = -1;
SKB_DR(reason);
u64 nonce = 0;
bool inc;
if (skb->len < sizeof(struct nd_msg))
return SKB_DROP_REASON_PKT_TOO_SMALL;
if (ipv6_addr_is_multicast(&msg->target)) {
ND_PRINTK(2, warn, "NS: multicast target address\n");
return reason;
}
/*
* 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 reason;
}
if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts))
return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
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 reason;
}
/* 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 reason;
}
}
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 reason;
} 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 reason;
}
if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
(READ_ONCE(idev->cnf.forwarding) &&
(READ_ONCE(net->ipv6.devconf_all->proxy_ndp) ||
READ_ONCE(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 {
SKB_DR_SET(reason, IPV6_NDISC_NS_OTHERHOST);
goto out;
}
}
if (is_router < 0)
is_router = READ_ONCE(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);
reason = SKB_CONSUMED;
}
out:
if (ifp)
in6_ifa_put(ifp);
else
in6_dev_put(idev);
return reason;
}
static int accept_untracked_na(struct net_device *dev, struct in6_addr *saddr)
{
struct inet6_dev *idev = __in6_dev_get(dev);
switch (READ_ONCE(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 enum skb_drop_reason 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;
SKB_DR(reason);
u8 new_state;
if (skb->len < sizeof(struct nd_msg))
return SKB_DROP_REASON_PKT_TOO_SMALL;
if (ipv6_addr_is_multicast(&msg->target)) {
ND_PRINTK(2, warn, "NA: target address is multicast\n");
return reason;
}
if (ipv6_addr_is_multicast(daddr) &&
msg->icmph.icmp6_solicited) {
ND_PRINTK(2, warn, "NA: solicited NA is multicasted\n");
return reason;
}
/* 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 &&
READ_ONCE(idev->cnf.drop_unsolicited_na))
return reason;
if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts))
return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
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 reason;
}
}
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 reason;
}
/* 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 reason;
}
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 && READ_ONCE(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) &&
READ_ONCE(net->ipv6.devconf_all->forwarding) &&
READ_ONCE(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);
}
reason = SKB_CONSUMED;
out:
neigh_release(neigh);
}
return reason;
}
static enum skb_drop_reason 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;
SKB_DR(reason);
if (skb->len < sizeof(*rs_msg))
return SKB_DROP_REASON_PKT_TOO_SMALL;
idev = __in6_dev_get(skb->dev);
if (!idev) {
ND_PRINTK(1, err, "RS: can't find in6 device\n");
return reason;
}
/* Don't accept RS if we're not in router mode */
if (!READ_ONCE(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))
return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
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);
reason = SKB_CONSUMED;
}
out:
return reason;
}
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 enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb)
{
struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
bool send_ifinfo_notify = false;
struct neighbour *neigh = NULL;
struct ndisc_options ndopts;
struct fib6_info *rt = NULL;
struct inet6_dev *in6_dev;
struct fib6_table *table;
u32 defrtr_usr_metric;
unsigned int pref = 0;
__u32 old_if_flags;
struct net *net;
SKB_DR(reason);
int lifetime;
int optlen;
__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 reason;
}
if (optlen < 0)
return SKB_DROP_REASON_PKT_TOO_SMALL;
#ifdef CONFIG_IPV6_NDISC_NODETYPE
if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) {
ND_PRINTK(2, warn, "RA: from host or unauthorized router\n");
return reason;
}
#endif
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 reason;
}
if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts))
return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
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 (!READ_ONCE(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 < READ_ONCE(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 (!READ_ONCE(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 ||
!READ_ONCE(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 reason;
}
}
/* 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,
lifetime);
if (!rt) {
ND_PRINTK(0, err,
"RA: %s failed to add default route\n",
__func__);
return reason;
}
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 reason;
}
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) {
table = rt->fib6_table;
spin_lock_bh(&table->tb6_lock);
fib6_set_expires(rt, jiffies + (HZ * lifetime));
fib6_add_gc_list(rt);
spin_unlock_bh(&table->tb6_lock);
}
if (READ_ONCE(in6_dev->cnf.accept_ra_min_hop_limit) < 256 &&
ra_msg->icmph.icmp6_hop_limit) {
if (READ_ONCE(in6_dev->cnf.accept_ra_min_hop_limit) <=
ra_msg->icmph.icmp6_hop_limit) {
WRITE_ONCE(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);
reason = SKB_CONSUMED;
}
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 (!READ_ONCE(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 (READ_ONCE(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 &&
!READ_ONCE(in6_dev->cnf.accept_ra_defrtr))
continue;
if (ri->lifetime != 0 &&
ntohl(ri->lifetime) < READ_ONCE(in6_dev->cnf.accept_ra_min_lft))
continue;
if (ri->prefix_len < READ_ONCE(in6_dev->cnf.accept_ra_rt_info_min_plen))
continue;
if (ri->prefix_len > READ_ONCE(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 (READ_ONCE(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 && READ_ONCE(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 (READ_ONCE(in6_dev->cnf.mtu6) != mtu) {
WRITE_ONCE(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);
return reason;
}
static enum skb_drop_reason ndisc_redirect_rcv(struct sk_buff *skb)
{
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));
struct ndisc_options ndopts;
SKB_DR(reason);
u8 *hdr;
#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 reason;
}
#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 reason;
}
if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts))
return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
if (!ndopts.nd_opts_rh) {
ip6_redirect_no_header(skb, dev_net(skb->dev),
skb->dev->ifindex);
return reason;
}
hdr = (u8 *)ndopts.nd_opts_rh;
hdr += 8;
if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
return SKB_DROP_REASON_PKT_TOO_SMALL;
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 = dst_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)
{
enum skb_drop_reason reason = ndisc_recv_ns(skb);
kfree_skb_reason(skb, reason);
}
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 &&
READ_ONCE(idev->cnf.suppress_frag_ndisc)) {
net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
return true;
}
return false;
}
enum skb_drop_reason ndisc_rcv(struct sk_buff *skb)
{
struct nd_msg *msg;
SKB_DR(reason);
if (ndisc_suppress_frag_ndisc(skb))
return SKB_DROP_REASON_IPV6_NDISC_FRAG;
if (skb_linearize(skb))
return SKB_DROP_REASON_NOMEM;
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 SKB_DROP_REASON_IPV6_NDISC_HOP_LIMIT;
}
if (msg->icmph.icmp6_code != 0) {
ND_PRINTK(2, warn, "NDISC: invalid ICMPv6 code: %d\n",
msg->icmph.icmp6_code);
return SKB_DROP_REASON_IPV6_NDISC_BAD_CODE;
}
switch (msg->icmph.icmp6_type) {
case NDISC_NEIGHBOUR_SOLICITATION:
memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
reason = ndisc_recv_ns(skb);
break;
case NDISC_NEIGHBOUR_ADVERTISEMENT:
reason = ndisc_recv_na(skb);
break;
case NDISC_ROUTER_SOLICITATION:
reason = ndisc_recv_rs(skb);
break;
case NDISC_ROUTER_ADVERTISEMENT:
reason = ndisc_router_discovery(skb);
break;
case NDISC_REDIRECT:
reason = ndisc_redirect_rcv(skb);
break;
}
return reason;
}
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 (READ_ONCE(idev->cnf.ndisc_notify) ||
READ_ONCE(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 = READ_ONCE(idev->cnf.ndisc_evict_nocarrier) &&
READ_ONCE(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(const 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) {
strscpy(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(const 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));
WRITE_ONCE(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 */
inet6_clear_bit(MC6_LOOP, sk);
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);
}
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