linux-next/net/ipv6/addrconf_core.c
Helge Deller 60365049cc ipv6: Ensure natural alignment of const ipv6 loopback and router addresses
On a parisc64 kernel I sometimes notice this kernel warning:
Kernel unaligned access to 0x40ff8814 at ndisc_send_skb+0xc0/0x4d8

The address 0x40ff8814 points to the in6addr_linklocal_allrouters
variable and the warning simply means that some ipv6 function tries to
read a 64-bit word directly from the not-64-bit aligned
in6addr_linklocal_allrouters variable.

Unaligned accesses are non-critical as the architecture or exception
handlers usually will fix it up at runtime. Nevertheless it may trigger
a performance penality for some architectures. For details read the
"unaligned-memory-access" kernel documentation.

The patch below ensures that the ipv6 loopback and router addresses will
always be naturally aligned. This prevents the unaligned accesses for
all architectures.

Signed-off-by: Helge Deller <deller@gmx.de>
Fixes: 034dfc5df9 ("ipv6: export in6addr_loopback to modules")
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/ZbNuFM1bFqoH-UoY@p100
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-01-30 12:43:18 +01:00

281 lines
8.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* IPv6 library code, needed by static components when full IPv6 support is
* not configured or static.
*/
#include <linux/export.h>
#include <net/ipv6.h>
#include <net/ipv6_stubs.h>
#include <net/addrconf.h>
#include <net/ip.h>
/* if ipv6 module registers this function is used by xfrm to force all
* sockets to relookup their nodes - this is fairly expensive, be
* careful
*/
void (*__fib6_flush_trees)(struct net *);
EXPORT_SYMBOL(__fib6_flush_trees);
#define IPV6_ADDR_SCOPE_TYPE(scope) ((scope) << 16)
static inline unsigned int ipv6_addr_scope2type(unsigned int scope)
{
switch (scope) {
case IPV6_ADDR_SCOPE_NODELOCAL:
return (IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_NODELOCAL) |
IPV6_ADDR_LOOPBACK);
case IPV6_ADDR_SCOPE_LINKLOCAL:
return (IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_LINKLOCAL) |
IPV6_ADDR_LINKLOCAL);
case IPV6_ADDR_SCOPE_SITELOCAL:
return (IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_SITELOCAL) |
IPV6_ADDR_SITELOCAL);
}
return IPV6_ADDR_SCOPE_TYPE(scope);
}
int __ipv6_addr_type(const struct in6_addr *addr)
{
__be32 st;
st = addr->s6_addr32[0];
/* Consider all addresses with the first three bits different of
000 and 111 as unicasts.
*/
if ((st & htonl(0xE0000000)) != htonl(0x00000000) &&
(st & htonl(0xE0000000)) != htonl(0xE0000000))
return (IPV6_ADDR_UNICAST |
IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL));
if ((st & htonl(0xFF000000)) == htonl(0xFF000000)) {
/* multicast */
/* addr-select 3.1 */
return (IPV6_ADDR_MULTICAST |
ipv6_addr_scope2type(IPV6_ADDR_MC_SCOPE(addr)));
}
if ((st & htonl(0xFFC00000)) == htonl(0xFE800000))
return (IPV6_ADDR_LINKLOCAL | IPV6_ADDR_UNICAST |
IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_LINKLOCAL)); /* addr-select 3.1 */
if ((st & htonl(0xFFC00000)) == htonl(0xFEC00000))
return (IPV6_ADDR_SITELOCAL | IPV6_ADDR_UNICAST |
IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_SITELOCAL)); /* addr-select 3.1 */
if ((st & htonl(0xFE000000)) == htonl(0xFC000000))
return (IPV6_ADDR_UNICAST |
IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL)); /* RFC 4193 */
if ((addr->s6_addr32[0] | addr->s6_addr32[1]) == 0) {
if (addr->s6_addr32[2] == 0) {
if (addr->s6_addr32[3] == 0)
return IPV6_ADDR_ANY;
if (addr->s6_addr32[3] == htonl(0x00000001))
return (IPV6_ADDR_LOOPBACK | IPV6_ADDR_UNICAST |
IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_LINKLOCAL)); /* addr-select 3.4 */
return (IPV6_ADDR_COMPATv4 | IPV6_ADDR_UNICAST |
IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL)); /* addr-select 3.3 */
}
if (addr->s6_addr32[2] == htonl(0x0000ffff))
return (IPV6_ADDR_MAPPED |
IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL)); /* addr-select 3.3 */
}
return (IPV6_ADDR_UNICAST |
IPV6_ADDR_SCOPE_TYPE(IPV6_ADDR_SCOPE_GLOBAL)); /* addr-select 3.4 */
}
EXPORT_SYMBOL(__ipv6_addr_type);
static ATOMIC_NOTIFIER_HEAD(inet6addr_chain);
static BLOCKING_NOTIFIER_HEAD(inet6addr_validator_chain);
int register_inet6addr_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&inet6addr_chain, nb);
}
EXPORT_SYMBOL(register_inet6addr_notifier);
int unregister_inet6addr_notifier(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&inet6addr_chain, nb);
}
EXPORT_SYMBOL(unregister_inet6addr_notifier);
int inet6addr_notifier_call_chain(unsigned long val, void *v)
{
return atomic_notifier_call_chain(&inet6addr_chain, val, v);
}
EXPORT_SYMBOL(inet6addr_notifier_call_chain);
int register_inet6addr_validator_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&inet6addr_validator_chain, nb);
}
EXPORT_SYMBOL(register_inet6addr_validator_notifier);
int unregister_inet6addr_validator_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&inet6addr_validator_chain,
nb);
}
EXPORT_SYMBOL(unregister_inet6addr_validator_notifier);
int inet6addr_validator_notifier_call_chain(unsigned long val, void *v)
{
return blocking_notifier_call_chain(&inet6addr_validator_chain, val, v);
}
EXPORT_SYMBOL(inet6addr_validator_notifier_call_chain);
static struct dst_entry *eafnosupport_ipv6_dst_lookup_flow(struct net *net,
const struct sock *sk,
struct flowi6 *fl6,
const struct in6_addr *final_dst)
{
return ERR_PTR(-EAFNOSUPPORT);
}
static int eafnosupport_ipv6_route_input(struct sk_buff *skb)
{
return -EAFNOSUPPORT;
}
static struct fib6_table *eafnosupport_fib6_get_table(struct net *net, u32 id)
{
return NULL;
}
static int
eafnosupport_fib6_table_lookup(struct net *net, struct fib6_table *table,
int oif, struct flowi6 *fl6,
struct fib6_result *res, int flags)
{
return -EAFNOSUPPORT;
}
static int
eafnosupport_fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
struct fib6_result *res, int flags)
{
return -EAFNOSUPPORT;
}
static void
eafnosupport_fib6_select_path(const struct net *net, struct fib6_result *res,
struct flowi6 *fl6, int oif, bool have_oif_match,
const struct sk_buff *skb, int strict)
{
}
static u32
eafnosupport_ip6_mtu_from_fib6(const struct fib6_result *res,
const struct in6_addr *daddr,
const struct in6_addr *saddr)
{
return 0;
}
static int eafnosupport_fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
struct fib6_config *cfg, gfp_t gfp_flags,
struct netlink_ext_ack *extack)
{
NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
return -EAFNOSUPPORT;
}
static int eafnosupport_ip6_del_rt(struct net *net, struct fib6_info *rt,
bool skip_notify)
{
return -EAFNOSUPPORT;
}
static int eafnosupport_ipv6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
int (*output)(struct net *, struct sock *, struct sk_buff *))
{
kfree_skb(skb);
return -EAFNOSUPPORT;
}
static struct net_device *eafnosupport_ipv6_dev_find(struct net *net, const struct in6_addr *addr,
struct net_device *dev)
{
return ERR_PTR(-EAFNOSUPPORT);
}
const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
.ipv6_dst_lookup_flow = eafnosupport_ipv6_dst_lookup_flow,
.ipv6_route_input = eafnosupport_ipv6_route_input,
.fib6_get_table = eafnosupport_fib6_get_table,
.fib6_table_lookup = eafnosupport_fib6_table_lookup,
.fib6_lookup = eafnosupport_fib6_lookup,
.fib6_select_path = eafnosupport_fib6_select_path,
.ip6_mtu_from_fib6 = eafnosupport_ip6_mtu_from_fib6,
.fib6_nh_init = eafnosupport_fib6_nh_init,
.ip6_del_rt = eafnosupport_ip6_del_rt,
.ipv6_fragment = eafnosupport_ipv6_fragment,
.ipv6_dev_find = eafnosupport_ipv6_dev_find,
};
EXPORT_SYMBOL_GPL(ipv6_stub);
/* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */
const struct in6_addr in6addr_loopback __aligned(BITS_PER_LONG/8)
= IN6ADDR_LOOPBACK_INIT;
EXPORT_SYMBOL(in6addr_loopback);
const struct in6_addr in6addr_any __aligned(BITS_PER_LONG/8)
= IN6ADDR_ANY_INIT;
EXPORT_SYMBOL(in6addr_any);
const struct in6_addr in6addr_linklocal_allnodes __aligned(BITS_PER_LONG/8)
= IN6ADDR_LINKLOCAL_ALLNODES_INIT;
EXPORT_SYMBOL(in6addr_linklocal_allnodes);
const struct in6_addr in6addr_linklocal_allrouters __aligned(BITS_PER_LONG/8)
= IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
EXPORT_SYMBOL(in6addr_linklocal_allrouters);
const struct in6_addr in6addr_interfacelocal_allnodes __aligned(BITS_PER_LONG/8)
= IN6ADDR_INTERFACELOCAL_ALLNODES_INIT;
EXPORT_SYMBOL(in6addr_interfacelocal_allnodes);
const struct in6_addr in6addr_interfacelocal_allrouters __aligned(BITS_PER_LONG/8)
= IN6ADDR_INTERFACELOCAL_ALLROUTERS_INIT;
EXPORT_SYMBOL(in6addr_interfacelocal_allrouters);
const struct in6_addr in6addr_sitelocal_allrouters __aligned(BITS_PER_LONG/8)
= IN6ADDR_SITELOCAL_ALLROUTERS_INIT;
EXPORT_SYMBOL(in6addr_sitelocal_allrouters);
static void snmp6_free_dev(struct inet6_dev *idev)
{
kfree(idev->stats.icmpv6msgdev);
kfree(idev->stats.icmpv6dev);
free_percpu(idev->stats.ipv6);
}
static void in6_dev_finish_destroy_rcu(struct rcu_head *head)
{
struct inet6_dev *idev = container_of(head, struct inet6_dev, rcu);
snmp6_free_dev(idev);
kfree(idev);
}
/* Nobody refers to this device, we may destroy it. */
void in6_dev_finish_destroy(struct inet6_dev *idev)
{
struct net_device *dev = idev->dev;
WARN_ON(!list_empty(&idev->addr_list));
WARN_ON(rcu_access_pointer(idev->mc_list));
WARN_ON(timer_pending(&idev->rs_timer));
#ifdef NET_REFCNT_DEBUG
pr_debug("%s: %s\n", __func__, dev ? dev->name : "NIL");
#endif
netdev_put(dev, &idev->dev_tracker);
if (!idev->dead) {
pr_warn("Freeing alive inet6 device %p\n", idev);
return;
}
call_rcu(&idev->rcu, in6_dev_finish_destroy_rcu);
}
EXPORT_SYMBOL(in6_dev_finish_destroy);