// SPDX-License-Identifier: GPL-2.0
/*
* IPv6 Address Label subsystem
* for the IPv6 "Default" Source Address Selection
*
* Copyright (C)2007 USAGI/WIDE Project
*/
/*
* Author:
* YOSHIFUJI Hideaki @ USAGI/WIDE Project <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/in6.h>
#include <linux/slab.h>
#include <net/addrconf.h>
#include <linux/if_addrlabel.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#if 0
#define ADDRLABEL(x...) printk(x)
#else
#define ADDRLABEL(x...) do { ; } while (0)
#endif
/*
* Policy Table
*/
struct ip6addrlbl_entry {
struct in6_addr prefix;
int prefixlen;
int ifindex;
int addrtype;
u32 label;
struct hlist_node list;
struct rcu_head rcu;
};
/*
* Default policy table (RFC6724 + extensions)
*
* prefix addr_type label
* -------------------------------------------------------------------------
* ::1/128 LOOPBACK 0
* ::/0 N/A 1
* 2002::/16 N/A 2
* ::/96 COMPATv4 3
* ::ffff:0:0/96 V4MAPPED 4
* fc00::/7 N/A 5 ULA (RFC 4193)
* 2001::/32 N/A 6 Teredo (RFC 4380)
* 2001:10::/28 N/A 7 ORCHID (RFC 4843)
* fec0::/10 N/A 11 Site-local
* (deprecated by RFC3879)
* 3ffe::/16 N/A 12 6bone
*
* Note: 0xffffffff is used if we do not have any policies.
* Note: Labels for ULA and 6to4 are different from labels listed in RFC6724.
*/
#define IPV6_ADDR_LABEL_DEFAULT 0xffffffffUL
static const __net_initconst struct ip6addrlbl_init_table
{
const struct in6_addr *prefix;
int prefixlen;
u32 label;
} ip6addrlbl_init_table[] = {
{ /* ::/0 */
.prefix = &in6addr_any,
.label = 1,
}, { /* fc00::/7 */
.prefix = &(struct in6_addr){ { { 0xfc } } } ,
.prefixlen = 7,
.label = 5,
}, { /* fec0::/10 */
.prefix = &(struct in6_addr){ { { 0xfe, 0xc0 } } },
.prefixlen = 10,
.label = 11,
}, { /* 2002::/16 */
.prefix = &(struct in6_addr){ { { 0x20, 0x02 } } },
.prefixlen = 16,
.label = 2,
}, { /* 3ffe::/16 */
.prefix = &(struct in6_addr){ { { 0x3f, 0xfe } } },
.prefixlen = 16,
.label = 12,
}, { /* 2001::/32 */
.prefix = &(struct in6_addr){ { { 0x20, 0x01 } } },
.prefixlen = 32,
.label = 6,
}, { /* 2001:10::/28 */
.prefix = &(struct in6_addr){ { { 0x20, 0x01, 0x00, 0x10 } } },
.prefixlen = 28,
.label = 7,
}, { /* ::ffff:0:0 */
.prefix = &(struct in6_addr){ { { [10] = 0xff, [11] = 0xff } } },
.prefixlen = 96,
.label = 4,
}, { /* ::/96 */
.prefix = &in6addr_any,
.prefixlen = 96,
.label = 3,
}, { /* ::1/128 */
.prefix = &in6addr_loopback,
.prefixlen = 128,
.label = 0,
}
};
/* Find label */
static bool __ip6addrlbl_match(const struct ip6addrlbl_entry *p,
const struct in6_addr *addr,
int addrtype, int ifindex)
{
if (p->ifindex && p->ifindex != ifindex)
return false;
if (p->addrtype && p->addrtype != addrtype)
return false;
if (!ipv6_prefix_equal(addr, &p->prefix, p->prefixlen))
return false;
return true;
}
static struct ip6addrlbl_entry *__ipv6_addr_label(struct net *net,
const struct in6_addr *addr,
int type, int ifindex)
{
struct ip6addrlbl_entry *p;
hlist_for_each_entry_rcu(p, &net->ipv6.ip6addrlbl_table.head, list) {
if (__ip6addrlbl_match(p, addr, type, ifindex))
return p;
}
return NULL;
}
u32 ipv6_addr_label(struct net *net,
const struct in6_addr *addr, int type, int ifindex)
{
u32 label;
struct ip6addrlbl_entry *p;
type &= IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK;
rcu_read_lock();
p = __ipv6_addr_label(net, addr, type, ifindex);
label = p ? p->label : IPV6_ADDR_LABEL_DEFAULT;
rcu_read_unlock();
ADDRLABEL(KERN_DEBUG "%s(addr=%pI6, type=%d, ifindex=%d) => %08x\n",
__func__, addr, type, ifindex, label);
return label;
}
/* allocate one entry */
static struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
int prefixlen, int ifindex,
u32 label)
{
struct ip6addrlbl_entry *newp;
int addrtype;
ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u)\n",
__func__, prefix, prefixlen, ifindex, (unsigned int)label);
addrtype = ipv6_addr_type(prefix) & (IPV6_ADDR_MAPPED | IPV6_ADDR_COMPATv4 | IPV6_ADDR_LOOPBACK);
switch (addrtype) {
case IPV6_ADDR_MAPPED:
if (prefixlen > 96)
return ERR_PTR(-EINVAL);
if (prefixlen < 96)
addrtype = 0;
break;
case IPV6_ADDR_COMPATv4:
if (prefixlen != 96)
addrtype = 0;
break;
case IPV6_ADDR_LOOPBACK:
if (prefixlen != 128)
addrtype = 0;
break;
}
newp = kmalloc(sizeof(*newp), GFP_KERNEL);
if (!newp)
return ERR_PTR(-ENOMEM);
ipv6_addr_prefix(&newp->prefix, prefix, prefixlen);
newp->prefixlen = prefixlen;
newp->ifindex = ifindex;
newp->addrtype = addrtype;
newp->label = label;
INIT_HLIST_NODE(&newp->list);
return newp;
}
/* add a label */
static int __ip6addrlbl_add(struct net *net, struct ip6addrlbl_entry *newp,
int replace)
{
struct ip6addrlbl_entry *last = NULL, *p = NULL;
struct hlist_node *n;
int ret = 0;
ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n", __func__, newp,
replace);
hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
if (p->prefixlen == newp->prefixlen &&
p->ifindex == newp->ifindex &&
ipv6_addr_equal(&p->prefix, &newp->prefix)) {
if (!replace) {
ret = -EEXIST;
goto out;
}
hlist_replace_rcu(&p->list, &newp->list);
kfree_rcu(p, rcu);
goto out;
} else if ((p->prefixlen == newp->prefixlen && !p->ifindex) ||
(p->prefixlen < newp->prefixlen)) {
hlist_add_before_rcu(&newp->list, &p->list);
goto out;
}
last = p;
}
if (last)
hlist_add_behind_rcu(&newp->list, &last->list);
else
hlist_add_head_rcu(&newp->list, &net->ipv6.ip6addrlbl_table.head);
out:
if (!ret)
WRITE_ONCE(net->ipv6.ip6addrlbl_table.seq,
net->ipv6.ip6addrlbl_table.seq + 1);
return ret;
}
/* add a label */
static int ip6addrlbl_add(struct net *net,
const struct in6_addr *prefix, int prefixlen,
int ifindex, u32 label, int replace)
{
struct ip6addrlbl_entry *newp;
int ret = 0;
ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d, label=%u, replace=%d)\n",
__func__, prefix, prefixlen, ifindex, (unsigned int)label,
replace);
newp = ip6addrlbl_alloc(prefix, prefixlen, ifindex, label);
if (IS_ERR(newp))
return PTR_ERR(newp);
spin_lock(&net->ipv6.ip6addrlbl_table.lock);
ret = __ip6addrlbl_add(net, newp, replace);
spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
if (ret)
kfree(newp);
return ret;
}
/* remove a label */
static int __ip6addrlbl_del(struct net *net,
const struct in6_addr *prefix, int prefixlen,
int ifindex)
{
struct ip6addrlbl_entry *p = NULL;
struct hlist_node *n;
int ret = -ESRCH;
ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n",
__func__, prefix, prefixlen, ifindex);
hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
if (p->prefixlen == prefixlen &&
p->ifindex == ifindex &&
ipv6_addr_equal(&p->prefix, prefix)) {
hlist_del_rcu(&p->list);
kfree_rcu(p, rcu);
ret = 0;
break;
}
}
return ret;
}
static int ip6addrlbl_del(struct net *net,
const struct in6_addr *prefix, int prefixlen,
int ifindex)
{
struct in6_addr prefix_buf;
int ret;
ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n",
__func__, prefix, prefixlen, ifindex);
ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
spin_lock(&net->ipv6.ip6addrlbl_table.lock);
ret = __ip6addrlbl_del(net, &prefix_buf, prefixlen, ifindex);
spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
return ret;
}
/* add default label */
static int __net_init ip6addrlbl_net_init(struct net *net)
{
struct ip6addrlbl_entry *p = NULL;
struct hlist_node *n;
int err;
int i;
ADDRLABEL(KERN_DEBUG "%s\n", __func__);
spin_lock_init(&net->ipv6.ip6addrlbl_table.lock);
INIT_HLIST_HEAD(&net->ipv6.ip6addrlbl_table.head);
for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
err = ip6addrlbl_add(net,
ip6addrlbl_init_table[i].prefix,
ip6addrlbl_init_table[i].prefixlen,
0,
ip6addrlbl_init_table[i].label, 0);
if (err)
goto err_ip6addrlbl_add;
}
return 0;
err_ip6addrlbl_add:
hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
hlist_del_rcu(&p->list);
kfree_rcu(p, rcu);
}
return err;
}
static void __net_exit ip6addrlbl_net_exit(struct net *net)
{
struct ip6addrlbl_entry *p = NULL;
struct hlist_node *n;
/* Remove all labels belonging to the exiting net */
spin_lock(&net->ipv6.ip6addrlbl_table.lock);
hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
hlist_del_rcu(&p->list);
kfree_rcu(p, rcu);
}
spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
}
static struct pernet_operations ipv6_addr_label_ops = {
.init = ip6addrlbl_net_init,
.exit = ip6addrlbl_net_exit,
};
int __init ipv6_addr_label_init(void)
{
return register_pernet_subsys(&ipv6_addr_label_ops);
}
void ipv6_addr_label_cleanup(void)
{
unregister_pernet_subsys(&ipv6_addr_label_ops);
}
static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
[IFAL_ADDRESS] = { .len = sizeof(struct in6_addr), },
[IFAL_LABEL] = { .len = sizeof(u32), },
};
static bool addrlbl_ifindex_exists(struct net *net, int ifindex)
{
struct net_device *dev;
rcu_read_lock();
dev = dev_get_by_index_rcu(net, ifindex);
rcu_read_unlock();
return dev != NULL;
}
static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct ifaddrlblmsg *ifal;
struct nlattr *tb[IFAL_MAX+1];
struct in6_addr *pfx;
u32 label;
int err = 0;
err = nlmsg_parse_deprecated(nlh, sizeof(*ifal), tb, IFAL_MAX,
ifal_policy, extack);
if (err < 0)
return err;
ifal = nlmsg_data(nlh);
if (ifal->ifal_family != AF_INET6 ||
ifal->ifal_prefixlen > 128)
return -EINVAL;
if (!tb[IFAL_ADDRESS])
return -EINVAL;
pfx = nla_data(tb[IFAL_ADDRESS]);
if (!tb[IFAL_LABEL])
return -EINVAL;
label = nla_get_u32(tb[IFAL_LABEL]);
if (label == IPV6_ADDR_LABEL_DEFAULT)
return -EINVAL;
switch (nlh->nlmsg_type) {
case RTM_NEWADDRLABEL:
if (ifal->ifal_index &&
!addrlbl_ifindex_exists(net, ifal->ifal_index))
return -EINVAL;
err = ip6addrlbl_add(net, pfx, ifal->ifal_prefixlen,
ifal->ifal_index, label,
nlh->nlmsg_flags & NLM_F_REPLACE);
break;
case RTM_DELADDRLABEL:
err = ip6addrlbl_del(net, pfx, ifal->ifal_prefixlen,
ifal->ifal_index);
break;
default:
err = -EOPNOTSUPP;
}
return err;
}
static void ip6addrlbl_putmsg(struct nlmsghdr *nlh,
int prefixlen, int ifindex, u32 lseq)
{
struct ifaddrlblmsg *ifal = nlmsg_data(nlh);
ifal->ifal_family = AF_INET6;
ifal->__ifal_reserved = 0;
ifal->ifal_prefixlen = prefixlen;
ifal->ifal_flags = 0;
ifal->ifal_index = ifindex;
ifal->ifal_seq = lseq;
};
static int ip6addrlbl_fill(struct sk_buff *skb,
const struct ip6addrlbl_entry *p,
u32 lseq,
u32 portid, u32 seq, int event,
unsigned int flags)
{
struct nlmsghdr *nlh = nlmsg_put(skb, portid, seq, event,
sizeof(struct ifaddrlblmsg), flags);
if (!nlh)
return -EMSGSIZE;
ip6addrlbl_putmsg(nlh, p->prefixlen, p->ifindex, lseq);
if (nla_put_in6_addr(skb, IFAL_ADDRESS, &p->prefix) < 0 ||
nla_put_u32(skb, IFAL_LABEL, p->label) < 0) {
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
nlmsg_end(skb, nlh);
return 0;
}
static int ip6addrlbl_valid_dump_req(const struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct ifaddrlblmsg *ifal;
if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifal))) {
NL_SET_ERR_MSG_MOD(extack, "Invalid header for address label dump request");
return -EINVAL;
}
ifal = nlmsg_data(nlh);
if (ifal->__ifal_reserved || ifal->ifal_prefixlen ||
ifal->ifal_flags || ifal->ifal_index || ifal->ifal_seq) {
NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for address label dump request");
return -EINVAL;
}
if (nlmsg_attrlen(nlh, sizeof(*ifal))) {
NL_SET_ERR_MSG_MOD(extack, "Invalid data after header for address label dump request");
return -EINVAL;
}
return 0;
}
static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
const struct nlmsghdr *nlh = cb->nlh;
struct net *net = sock_net(skb->sk);
struct ip6addrlbl_entry *p;
int idx = 0, s_idx = cb->args[0];
int err = 0;
u32 lseq;
if (cb->strict_check) {
err = ip6addrlbl_valid_dump_req(nlh, cb->extack);
if (err < 0)
return err;
}
rcu_read_lock();
lseq = READ_ONCE(net->ipv6.ip6addrlbl_table.seq);
hlist_for_each_entry_rcu(p, &net->ipv6.ip6addrlbl_table.head, list) {
if (idx >= s_idx) {
err = ip6addrlbl_fill(skb, p,
lseq,
NETLINK_CB(cb->skb).portid,
nlh->nlmsg_seq,
RTM_NEWADDRLABEL,
NLM_F_MULTI);
if (err < 0)
break;
}
idx++;
}
rcu_read_unlock();
cb->args[0] = idx;
return err;
}
static inline int ip6addrlbl_msgsize(void)
{
return NLMSG_ALIGN(sizeof(struct ifaddrlblmsg))
+ nla_total_size(16) /* IFAL_ADDRESS */
+ nla_total_size(4); /* IFAL_LABEL */
}
static int ip6addrlbl_valid_get_req(struct sk_buff *skb,
const struct nlmsghdr *nlh,
struct nlattr **tb,
struct netlink_ext_ack *extack)
{
struct ifaddrlblmsg *ifal;
int i, err;
if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifal))) {
NL_SET_ERR_MSG_MOD(extack, "Invalid header for addrlabel get request");
return -EINVAL;
}
if (!netlink_strict_get_check(skb))
return nlmsg_parse_deprecated(nlh, sizeof(*ifal), tb,
IFAL_MAX, ifal_policy, extack);
ifal = nlmsg_data(nlh);
if (ifal->__ifal_reserved || ifal->ifal_flags || ifal->ifal_seq) {
NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for addrlabel get request");
return -EINVAL;
}
err = nlmsg_parse_deprecated_strict(nlh, sizeof(*ifal), tb, IFAL_MAX,
ifal_policy, extack);
if (err)
return err;
for (i = 0; i <= IFAL_MAX; i++) {
if (!tb[i])
continue;
switch (i) {
case IFAL_ADDRESS:
break;
default:
NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in addrlabel get request");
return -EINVAL;
}
}
return 0;
}
static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(in_skb->sk);
struct ifaddrlblmsg *ifal;
struct nlattr *tb[IFAL_MAX+1];
struct in6_addr *addr;
u32 lseq;
int err = 0;
struct ip6addrlbl_entry *p;
struct sk_buff *skb;
err = ip6addrlbl_valid_get_req(in_skb, nlh, tb, extack);
if (err < 0)
return err;
ifal = nlmsg_data(nlh);
if (ifal->ifal_family != AF_INET6 ||
ifal->ifal_prefixlen != 128)
return -EINVAL;
if (ifal->ifal_index &&
!addrlbl_ifindex_exists(net, ifal->ifal_index))
return -EINVAL;
if (!tb[IFAL_ADDRESS])
return -EINVAL;
addr = nla_data(tb[IFAL_ADDRESS]);
skb = nlmsg_new(ip6addrlbl_msgsize(), GFP_KERNEL);
if (!skb)
return -ENOBUFS;
err = -ESRCH;
rcu_read_lock();
p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
lseq = READ_ONCE(net->ipv6.ip6addrlbl_table.seq);
if (p)
err = ip6addrlbl_fill(skb, p, lseq,
NETLINK_CB(in_skb).portid,
nlh->nlmsg_seq,
RTM_NEWADDRLABEL, 0);
rcu_read_unlock();
if (err < 0) {
WARN_ON(err == -EMSGSIZE);
kfree_skb(skb);
} else {
err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
}
return err;
}
int __init ipv6_addr_label_rtnl_register(void)
{
int ret;
ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_NEWADDRLABEL,
ip6addrlbl_newdel,
NULL, RTNL_FLAG_DOIT_UNLOCKED);
if (ret < 0)
return ret;
ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_DELADDRLABEL,
ip6addrlbl_newdel,
NULL, RTNL_FLAG_DOIT_UNLOCKED);
if (ret < 0)
return ret;
ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETADDRLABEL,
ip6addrlbl_get,
ip6addrlbl_dump, RTNL_FLAG_DOIT_UNLOCKED |
RTNL_FLAG_DUMP_UNLOCKED);
return ret;
}
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