linux/net/ipv6/anycast.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

613 lines
13 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Anycast support for IPv6
* Linux INET6 implementation
*
* Authors:
* David L Stevens (dlstevens@us.ibm.com)
*
* based heavily on net/ipv6/mcast.c
*/
#include <linux/capability.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/random.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/route.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/snmp.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/if_inet6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/checksum.h>
#define IN6_ADDR_HSIZE_SHIFT 8
#define IN6_ADDR_HSIZE BIT(IN6_ADDR_HSIZE_SHIFT)
/* anycast address hash table
*/
static struct hlist_head inet6_acaddr_lst[IN6_ADDR_HSIZE];
static DEFINE_SPINLOCK(acaddr_hash_lock);
static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr);
static u32 inet6_acaddr_hash(struct net *net, const struct in6_addr *addr)
{
u32 val = ipv6_addr_hash(addr) ^ net_hash_mix(net);
return hash_32(val, IN6_ADDR_HSIZE_SHIFT);
}
/*
* socket join an anycast group
*/
int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct net_device *dev = NULL;
struct inet6_dev *idev;
struct ipv6_ac_socklist *pac;
struct net *net = sock_net(sk);
int ishost = !net->ipv6.devconf_all->forwarding;
int err = 0;
ASSERT_RTNL();
if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
return -EPERM;
if (ipv6_addr_is_multicast(addr))
return -EINVAL;
if (ifindex)
dev = __dev_get_by_index(net, ifindex);
if (ipv6_chk_addr_and_flags(net, addr, dev, true, 0, IFA_F_TENTATIVE))
return -EINVAL;
pac = sock_kmalloc(sk, sizeof(struct ipv6_ac_socklist), GFP_KERNEL);
if (!pac)
return -ENOMEM;
pac->acl_next = NULL;
pac->acl_addr = *addr;
if (ifindex == 0) {
struct rt6_info *rt;
rt = rt6_lookup(net, addr, NULL, 0, NULL, 0);
if (rt) {
dev = rt->dst.dev;
ip6_rt_put(rt);
} else if (ishost) {
err = -EADDRNOTAVAIL;
goto error;
} else {
/* router, no matching interface: just pick one */
dev = __dev_get_by_flags(net, IFF_UP,
IFF_UP | IFF_LOOPBACK);
}
}
if (!dev) {
err = -ENODEV;
goto error;
}
idev = __in6_dev_get(dev);
if (!idev) {
if (ifindex)
err = -ENODEV;
else
err = -EADDRNOTAVAIL;
goto error;
}
/* reset ishost, now that we have a specific device */
ishost = !idev->cnf.forwarding;
pac->acl_ifindex = dev->ifindex;
/* XXX
* For hosts, allow link-local or matching prefix anycasts.
* This obviates the need for propagating anycast routes while
* still allowing some non-router anycast participation.
*/
if (!ipv6_chk_prefix(addr, dev)) {
if (ishost)
err = -EADDRNOTAVAIL;
if (err)
goto error;
}
err = __ipv6_dev_ac_inc(idev, addr);
if (!err) {
pac->acl_next = np->ipv6_ac_list;
np->ipv6_ac_list = pac;
pac = NULL;
}
error:
if (pac)
sock_kfree_s(sk, pac, sizeof(*pac));
return err;
}
/*
* socket leave an anycast group
*/
int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct net_device *dev;
struct ipv6_ac_socklist *pac, *prev_pac;
struct net *net = sock_net(sk);
ASSERT_RTNL();
prev_pac = NULL;
for (pac = np->ipv6_ac_list; pac; pac = pac->acl_next) {
if ((ifindex == 0 || pac->acl_ifindex == ifindex) &&
ipv6_addr_equal(&pac->acl_addr, addr))
break;
prev_pac = pac;
}
if (!pac)
return -ENOENT;
if (prev_pac)
prev_pac->acl_next = pac->acl_next;
else
np->ipv6_ac_list = pac->acl_next;
dev = __dev_get_by_index(net, pac->acl_ifindex);
if (dev)
ipv6_dev_ac_dec(dev, &pac->acl_addr);
sock_kfree_s(sk, pac, sizeof(*pac));
return 0;
}
void ipv6_sock_ac_close(struct sock *sk)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct net_device *dev = NULL;
struct ipv6_ac_socklist *pac;
struct net *net = sock_net(sk);
int prev_index;
if (!np->ipv6_ac_list)
return;
rtnl_lock();
pac = np->ipv6_ac_list;
np->ipv6_ac_list = NULL;
prev_index = 0;
while (pac) {
struct ipv6_ac_socklist *next = pac->acl_next;
if (pac->acl_ifindex != prev_index) {
dev = __dev_get_by_index(net, pac->acl_ifindex);
prev_index = pac->acl_ifindex;
}
if (dev)
ipv6_dev_ac_dec(dev, &pac->acl_addr);
sock_kfree_s(sk, pac, sizeof(*pac));
pac = next;
}
rtnl_unlock();
}
static void ipv6_add_acaddr_hash(struct net *net, struct ifacaddr6 *aca)
{
unsigned int hash = inet6_acaddr_hash(net, &aca->aca_addr);
spin_lock(&acaddr_hash_lock);
hlist_add_head_rcu(&aca->aca_addr_lst, &inet6_acaddr_lst[hash]);
spin_unlock(&acaddr_hash_lock);
}
static void ipv6_del_acaddr_hash(struct ifacaddr6 *aca)
{
spin_lock(&acaddr_hash_lock);
hlist_del_init_rcu(&aca->aca_addr_lst);
spin_unlock(&acaddr_hash_lock);
}
static void aca_get(struct ifacaddr6 *aca)
{
refcount_inc(&aca->aca_refcnt);
}
static void aca_free_rcu(struct rcu_head *h)
{
struct ifacaddr6 *aca = container_of(h, struct ifacaddr6, rcu);
fib6_info_release(aca->aca_rt);
kfree(aca);
}
static void aca_put(struct ifacaddr6 *ac)
{
if (refcount_dec_and_test(&ac->aca_refcnt)) {
call_rcu(&ac->rcu, aca_free_rcu);
}
}
static struct ifacaddr6 *aca_alloc(struct fib6_info *f6i,
const struct in6_addr *addr)
{
struct ifacaddr6 *aca;
aca = kzalloc(sizeof(*aca), GFP_ATOMIC);
if (!aca)
return NULL;
aca->aca_addr = *addr;
fib6_info_hold(f6i);
aca->aca_rt = f6i;
INIT_HLIST_NODE(&aca->aca_addr_lst);
aca->aca_users = 1;
/* aca_tstamp should be updated upon changes */
aca->aca_cstamp = aca->aca_tstamp = jiffies;
refcount_set(&aca->aca_refcnt, 1);
return aca;
}
/*
* device anycast group inc (add if not found)
*/
int __ipv6_dev_ac_inc(struct inet6_dev *idev, const struct in6_addr *addr)
{
struct ifacaddr6 *aca;
struct fib6_info *f6i;
struct net *net;
int err;
ASSERT_RTNL();
write_lock_bh(&idev->lock);
if (idev->dead) {
err = -ENODEV;
goto out;
}
for (aca = idev->ac_list; aca; aca = aca->aca_next) {
if (ipv6_addr_equal(&aca->aca_addr, addr)) {
aca->aca_users++;
err = 0;
goto out;
}
}
net = dev_net(idev->dev);
f6i = addrconf_f6i_alloc(net, idev, addr, true, GFP_ATOMIC);
if (IS_ERR(f6i)) {
err = PTR_ERR(f6i);
goto out;
}
aca = aca_alloc(f6i, addr);
if (!aca) {
fib6_info_release(f6i);
err = -ENOMEM;
goto out;
}
aca->aca_next = idev->ac_list;
idev->ac_list = aca;
/* Hold this for addrconf_join_solict() below before we unlock,
* it is already exposed via idev->ac_list.
*/
aca_get(aca);
write_unlock_bh(&idev->lock);
ipv6_add_acaddr_hash(net, aca);
ip6_ins_rt(net, f6i);
addrconf_join_solict(idev->dev, &aca->aca_addr);
aca_put(aca);
return 0;
out:
write_unlock_bh(&idev->lock);
return err;
}
/*
* device anycast group decrement
*/
int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr)
{
struct ifacaddr6 *aca, *prev_aca;
ASSERT_RTNL();
write_lock_bh(&idev->lock);
prev_aca = NULL;
for (aca = idev->ac_list; aca; aca = aca->aca_next) {
if (ipv6_addr_equal(&aca->aca_addr, addr))
break;
prev_aca = aca;
}
if (!aca) {
write_unlock_bh(&idev->lock);
return -ENOENT;
}
if (--aca->aca_users > 0) {
write_unlock_bh(&idev->lock);
return 0;
}
if (prev_aca)
prev_aca->aca_next = aca->aca_next;
else
idev->ac_list = aca->aca_next;
write_unlock_bh(&idev->lock);
ipv6_del_acaddr_hash(aca);
addrconf_leave_solict(idev, &aca->aca_addr);
ip6_del_rt(dev_net(idev->dev), aca->aca_rt);
aca_put(aca);
return 0;
}
/* called with rtnl_lock() */
static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr)
{
struct inet6_dev *idev = __in6_dev_get(dev);
if (!idev)
return -ENODEV;
return __ipv6_dev_ac_dec(idev, addr);
}
void ipv6_ac_destroy_dev(struct inet6_dev *idev)
{
struct ifacaddr6 *aca;
write_lock_bh(&idev->lock);
while ((aca = idev->ac_list) != NULL) {
idev->ac_list = aca->aca_next;
write_unlock_bh(&idev->lock);
ipv6_del_acaddr_hash(aca);
addrconf_leave_solict(idev, &aca->aca_addr);
ip6_del_rt(dev_net(idev->dev), aca->aca_rt);
aca_put(aca);
write_lock_bh(&idev->lock);
}
write_unlock_bh(&idev->lock);
}
/*
* check if the interface has this anycast address
* called with rcu_read_lock()
*/
static bool ipv6_chk_acast_dev(struct net_device *dev, const struct in6_addr *addr)
{
struct inet6_dev *idev;
struct ifacaddr6 *aca;
idev = __in6_dev_get(dev);
if (idev) {
read_lock_bh(&idev->lock);
for (aca = idev->ac_list; aca; aca = aca->aca_next)
if (ipv6_addr_equal(&aca->aca_addr, addr))
break;
read_unlock_bh(&idev->lock);
return aca != NULL;
}
return false;
}
/*
* check if given interface (or any, if dev==0) has this anycast address
*/
bool ipv6_chk_acast_addr(struct net *net, struct net_device *dev,
const struct in6_addr *addr)
{
struct net_device *nh_dev;
struct ifacaddr6 *aca;
bool found = false;
rcu_read_lock();
if (dev)
found = ipv6_chk_acast_dev(dev, addr);
else {
unsigned int hash = inet6_acaddr_hash(net, addr);
hlist_for_each_entry_rcu(aca, &inet6_acaddr_lst[hash],
aca_addr_lst) {
nh_dev = fib6_info_nh_dev(aca->aca_rt);
if (!nh_dev || !net_eq(dev_net(nh_dev), net))
continue;
if (ipv6_addr_equal(&aca->aca_addr, addr)) {
found = true;
break;
}
}
}
rcu_read_unlock();
return found;
}
/* check if this anycast address is link-local on given interface or
* is global
*/
bool ipv6_chk_acast_addr_src(struct net *net, struct net_device *dev,
const struct in6_addr *addr)
{
return ipv6_chk_acast_addr(net,
(ipv6_addr_type(addr) & IPV6_ADDR_LINKLOCAL ?
dev : NULL),
addr);
}
#ifdef CONFIG_PROC_FS
struct ac6_iter_state {
struct seq_net_private p;
struct net_device *dev;
struct inet6_dev *idev;
};
#define ac6_seq_private(seq) ((struct ac6_iter_state *)(seq)->private)
static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
{
struct ifacaddr6 *im = NULL;
struct ac6_iter_state *state = ac6_seq_private(seq);
struct net *net = seq_file_net(seq);
state->idev = NULL;
for_each_netdev_rcu(net, state->dev) {
struct inet6_dev *idev;
idev = __in6_dev_get(state->dev);
if (!idev)
continue;
read_lock_bh(&idev->lock);
im = idev->ac_list;
if (im) {
state->idev = idev;
break;
}
read_unlock_bh(&idev->lock);
}
return im;
}
static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im)
{
struct ac6_iter_state *state = ac6_seq_private(seq);
im = im->aca_next;
while (!im) {
if (likely(state->idev != NULL))
read_unlock_bh(&state->idev->lock);
state->dev = next_net_device_rcu(state->dev);
if (!state->dev) {
state->idev = NULL;
break;
}
state->idev = __in6_dev_get(state->dev);
if (!state->idev)
continue;
read_lock_bh(&state->idev->lock);
im = state->idev->ac_list;
}
return im;
}
static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
{
struct ifacaddr6 *im = ac6_get_first(seq);
if (im)
while (pos && (im = ac6_get_next(seq, im)) != NULL)
--pos;
return pos ? NULL : im;
}
static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(RCU)
{
rcu_read_lock();
return ac6_get_idx(seq, *pos);
}
static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct ifacaddr6 *im = ac6_get_next(seq, v);
++*pos;
return im;
}
static void ac6_seq_stop(struct seq_file *seq, void *v)
__releases(RCU)
{
struct ac6_iter_state *state = ac6_seq_private(seq);
if (likely(state->idev != NULL)) {
read_unlock_bh(&state->idev->lock);
state->idev = NULL;
}
rcu_read_unlock();
}
static int ac6_seq_show(struct seq_file *seq, void *v)
{
struct ifacaddr6 *im = (struct ifacaddr6 *)v;
struct ac6_iter_state *state = ac6_seq_private(seq);
seq_printf(seq, "%-4d %-15s %pi6 %5d\n",
state->dev->ifindex, state->dev->name,
&im->aca_addr, im->aca_users);
return 0;
}
static const struct seq_operations ac6_seq_ops = {
.start = ac6_seq_start,
.next = ac6_seq_next,
.stop = ac6_seq_stop,
.show = ac6_seq_show,
};
int __net_init ac6_proc_init(struct net *net)
{
if (!proc_create_net("anycast6", 0444, net->proc_net, &ac6_seq_ops,
sizeof(struct ac6_iter_state)))
return -ENOMEM;
return 0;
}
void ac6_proc_exit(struct net *net)
{
remove_proc_entry("anycast6", net->proc_net);
}
#endif
/* Init / cleanup code
*/
int __init ipv6_anycast_init(void)
{
int i;
for (i = 0; i < IN6_ADDR_HSIZE; i++)
INIT_HLIST_HEAD(&inet6_acaddr_lst[i]);
return 0;
}
void ipv6_anycast_cleanup(void)
{
int i;
spin_lock(&acaddr_hash_lock);
for (i = 0; i < IN6_ADDR_HSIZE; i++)
WARN_ON(!hlist_empty(&inet6_acaddr_lst[i]));
spin_unlock(&acaddr_hash_lock);
}