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linux/net/core/fib_rules.c
Ido Schimmel 3c71006d15 ipv4: fib_rules: Check if rule is a default rule 
Currently, when non-default (custom) FIB rules are used, devices capable
of layer 3 offloading flush their tables and let the kernel do the
forwarding instead.

When these devices' drivers are loaded they register to the FIB
notification chain, which lets them know about the existence of any
custom FIB rules. This is done by sending a RULE_ADD notification based
on the value of 'net->ipv4.fib_has_custom_rules'.

This approach is problematic when VRF offload is taken into account, as
upon the creation of the first VRF netdev, a l3mdev rule is programmed
to direct skbs to the VRF's table.

Instead of merely reading the above value and sending a single RULE_ADD
notification, we should iterate over all the FIB rules and send a
detailed notification for each, thereby allowing offloading drivers to
sanitize the rules they don't support and potentially flush their
tables.

While l3mdev rules are uniquely marked, the default rules are not.
Therefore, when they are being notified they might invoke offloading
drivers to unnecessarily flush their tables.

Solve this by adding an helper to check if a FIB rule is a default rule.
Namely, its selector should match all packets and its action should
point to the local, main or default tables.

As noted by David Ahern, uniquely marking the default rules is
insufficient. When using VRFs, it's common to avoid false hits by moving
the rule for the local table to just before the main table:

Default configuration:
$ ip rule show
0:      from all lookup local
32766:  from all lookup main
32767:  from all lookup default

Common configuration with VRFs:
$ ip rule show
1000:   from all lookup [l3mdev-table]
32765:  from all lookup local
32766:  from all lookup main
32767:  from all lookup default

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-16 10:18:33 -07:00

980 lines
22 KiB
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Raw Blame History

/*
* net/core/fib_rules.c Generic Routing Rules
*
* 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, version 2.
*
* Authors: Thomas Graf <tgraf@suug.ch>
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/module.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/fib_rules.h>
#include <net/ip_tunnels.h>
static const struct fib_kuid_range fib_kuid_range_unset = {
KUIDT_INIT(0),
KUIDT_INIT(~0),
};
bool fib_rule_matchall(const struct fib_rule *rule)
{
if (rule->iifindex || rule->oifindex || rule->mark || rule->tun_id ||
rule->flags)
return false;
if (rule->suppress_ifgroup != -1 || rule->suppress_prefixlen != -1)
return false;
if (!uid_eq(rule->uid_range.start, fib_kuid_range_unset.start) ||
!uid_eq(rule->uid_range.end, fib_kuid_range_unset.end))
return false;
return true;
}
EXPORT_SYMBOL_GPL(fib_rule_matchall);
int fib_default_rule_add(struct fib_rules_ops *ops,
u32 pref, u32 table, u32 flags)
{
struct fib_rule *r;
r = kzalloc(ops->rule_size, GFP_KERNEL);
if (r == NULL)
return -ENOMEM;
atomic_set(&r->refcnt, 1);
r->action = FR_ACT_TO_TBL;
r->pref = pref;
r->table = table;
r->flags = flags;
r->fr_net = ops->fro_net;
r->uid_range = fib_kuid_range_unset;
r->suppress_prefixlen = -1;
r->suppress_ifgroup = -1;
/* The lock is not required here, the list in unreacheable
* at the moment this function is called */
list_add_tail(&r->list, &ops->rules_list);
return 0;
}
EXPORT_SYMBOL(fib_default_rule_add);
static u32 fib_default_rule_pref(struct fib_rules_ops *ops)
{
struct list_head *pos;
struct fib_rule *rule;
if (!list_empty(&ops->rules_list)) {
pos = ops->rules_list.next;
if (pos->next != &ops->rules_list) {
rule = list_entry(pos->next, struct fib_rule, list);
if (rule->pref)
return rule->pref - 1;
}
}
return 0;
}
static void notify_rule_change(int event, struct fib_rule *rule,
struct fib_rules_ops *ops, struct nlmsghdr *nlh,
u32 pid);
static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
{
struct fib_rules_ops *ops;
rcu_read_lock();
list_for_each_entry_rcu(ops, &net->rules_ops, list) {
if (ops->family == family) {
if (!try_module_get(ops->owner))
ops = NULL;
rcu_read_unlock();
return ops;
}
}
rcu_read_unlock();
return NULL;
}
static void rules_ops_put(struct fib_rules_ops *ops)
{
if (ops)
module_put(ops->owner);
}
static void flush_route_cache(struct fib_rules_ops *ops)
{
if (ops->flush_cache)
ops->flush_cache(ops);
}
static int __fib_rules_register(struct fib_rules_ops *ops)
{
int err = -EEXIST;
struct fib_rules_ops *o;
struct net *net;
net = ops->fro_net;
if (ops->rule_size < sizeof(struct fib_rule))
return -EINVAL;
if (ops->match == NULL || ops->configure == NULL ||
ops->compare == NULL || ops->fill == NULL ||
ops->action == NULL)
return -EINVAL;
spin_lock(&net->rules_mod_lock);
list_for_each_entry(o, &net->rules_ops, list)
if (ops->family == o->family)
goto errout;
list_add_tail_rcu(&ops->list, &net->rules_ops);
err = 0;
errout:
spin_unlock(&net->rules_mod_lock);
return err;
}
struct fib_rules_ops *
fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net)
{
struct fib_rules_ops *ops;
int err;
ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
if (ops == NULL)
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&ops->rules_list);
ops->fro_net = net;
err = __fib_rules_register(ops);
if (err) {
kfree(ops);
ops = ERR_PTR(err);
}
return ops;
}
EXPORT_SYMBOL_GPL(fib_rules_register);
static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
{
struct fib_rule *rule, *tmp;
list_for_each_entry_safe(rule, tmp, &ops->rules_list, list) {
list_del_rcu(&rule->list);
if (ops->delete)
ops->delete(rule);
fib_rule_put(rule);
}
}
void fib_rules_unregister(struct fib_rules_ops *ops)
{
struct net *net = ops->fro_net;
spin_lock(&net->rules_mod_lock);
list_del_rcu(&ops->list);
spin_unlock(&net->rules_mod_lock);
fib_rules_cleanup_ops(ops);
kfree_rcu(ops, rcu);
}
EXPORT_SYMBOL_GPL(fib_rules_unregister);
static int uid_range_set(struct fib_kuid_range *range)
{
return uid_valid(range->start) && uid_valid(range->end);
}
static struct fib_kuid_range nla_get_kuid_range(struct nlattr **tb)
{
struct fib_rule_uid_range *in;
struct fib_kuid_range out;
in = (struct fib_rule_uid_range *)nla_data(tb[FRA_UID_RANGE]);
out.start = make_kuid(current_user_ns(), in->start);
out.end = make_kuid(current_user_ns(), in->end);
return out;
}
static int nla_put_uid_range(struct sk_buff *skb, struct fib_kuid_range *range)
{
struct fib_rule_uid_range out = {
from_kuid_munged(current_user_ns(), range->start),
from_kuid_munged(current_user_ns(), range->end)
};
return nla_put(skb, FRA_UID_RANGE, sizeof(out), &out);
}
static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
struct flowi *fl, int flags,
struct fib_lookup_arg *arg)
{
int ret = 0;
if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
goto out;
if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
goto out;
if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
goto out;
if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
goto out;
if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
goto out;
if (uid_lt(fl->flowi_uid, rule->uid_range.start) ||
uid_gt(fl->flowi_uid, rule->uid_range.end))
goto out;
ret = ops->match(rule, fl, flags);
out:
return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
}
int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
int flags, struct fib_lookup_arg *arg)
{
struct fib_rule *rule;
int err;
rcu_read_lock();
list_for_each_entry_rcu(rule, &ops->rules_list, list) {
jumped:
if (!fib_rule_match(rule, ops, fl, flags, arg))
continue;
if (rule->action == FR_ACT_GOTO) {
struct fib_rule *target;
target = rcu_dereference(rule->ctarget);
if (target == NULL) {
continue;
} else {
rule = target;
goto jumped;
}
} else if (rule->action == FR_ACT_NOP)
continue;
else
err = ops->action(rule, fl, flags, arg);
if (!err && ops->suppress && ops->suppress(rule, arg))
continue;
if (err != -EAGAIN) {
if ((arg->flags & FIB_LOOKUP_NOREF) ||
likely(atomic_inc_not_zero(&rule->refcnt))) {
arg->rule = rule;
goto out;
}
break;
}
}
err = -ESRCH;
out:
rcu_read_unlock();
return err;
}
EXPORT_SYMBOL_GPL(fib_rules_lookup);
static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
struct fib_rules_ops *ops)
{
int err = -EINVAL;
if (frh->src_len)
if (tb[FRA_SRC] == NULL ||
frh->src_len > (ops->addr_size * 8) ||
nla_len(tb[FRA_SRC]) != ops->addr_size)
goto errout;
if (frh->dst_len)
if (tb[FRA_DST] == NULL ||
frh->dst_len > (ops->addr_size * 8) ||
nla_len(tb[FRA_DST]) != ops->addr_size)
goto errout;
err = 0;
errout:
return err;
}
static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
struct nlattr **tb, struct fib_rule *rule)
{
struct fib_rule *r;
list_for_each_entry(r, &ops->rules_list, list) {
if (r->action != rule->action)
continue;
if (r->table != rule->table)
continue;
if (r->pref != rule->pref)
continue;
if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
continue;
if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
continue;
if (r->mark != rule->mark)
continue;
if (r->mark_mask != rule->mark_mask)
continue;
if (r->tun_id != rule->tun_id)
continue;
if (r->fr_net != rule->fr_net)
continue;
if (r->l3mdev != rule->l3mdev)
continue;
if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
!uid_eq(r->uid_range.end, rule->uid_range.end))
continue;
if (!ops->compare(r, frh, tb))
continue;
return 1;
}
return 0;
}
int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh)
{
struct net *net = sock_net(skb->sk);
struct fib_rule_hdr *frh = nlmsg_data(nlh);
struct fib_rules_ops *ops = NULL;
struct fib_rule *rule, *r, *last = NULL;
struct nlattr *tb[FRA_MAX+1];
int err = -EINVAL, unresolved = 0;
if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
goto errout;
ops = lookup_rules_ops(net, frh->family);
if (ops == NULL) {
err = -EAFNOSUPPORT;
goto errout;
}
err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
if (err < 0)
goto errout;
err = validate_rulemsg(frh, tb, ops);
if (err < 0)
goto errout;
rule = kzalloc(ops->rule_size, GFP_KERNEL);
if (rule == NULL) {
err = -ENOMEM;
goto errout;
}
rule->fr_net = net;
rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
: fib_default_rule_pref(ops);
if (tb[FRA_IIFNAME]) {
struct net_device *dev;
rule->iifindex = -1;
nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
dev = __dev_get_by_name(net, rule->iifname);
if (dev)
rule->iifindex = dev->ifindex;
}
if (tb[FRA_OIFNAME]) {
struct net_device *dev;
rule->oifindex = -1;
nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
dev = __dev_get_by_name(net, rule->oifname);
if (dev)
rule->oifindex = dev->ifindex;
}
if (tb[FRA_FWMARK]) {
rule->mark = nla_get_u32(tb[FRA_FWMARK]);
if (rule->mark)
/* compatibility: if the mark value is non-zero all bits
* are compared unless a mask is explicitly specified.
*/
rule->mark_mask = 0xFFFFFFFF;
}
if (tb[FRA_FWMASK])
rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
if (tb[FRA_TUN_ID])
rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
if (tb[FRA_L3MDEV]) {
#ifdef CONFIG_NET_L3_MASTER_DEV
rule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
if (rule->l3mdev != 1)
#endif
goto errout_free;
}
rule->action = frh->action;
rule->flags = frh->flags;
rule->table = frh_get_table(frh, tb);
if (tb[FRA_SUPPRESS_PREFIXLEN])
rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
else
rule->suppress_prefixlen = -1;
if (tb[FRA_SUPPRESS_IFGROUP])
rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
else
rule->suppress_ifgroup = -1;
err = -EINVAL;
if (tb[FRA_GOTO]) {
if (rule->action != FR_ACT_GOTO)
goto errout_free;
rule->target = nla_get_u32(tb[FRA_GOTO]);
/* Backward jumps are prohibited to avoid endless loops */
if (rule->target <= rule->pref)
goto errout_free;
list_for_each_entry(r, &ops->rules_list, list) {
if (r->pref == rule->target) {
RCU_INIT_POINTER(rule->ctarget, r);
break;
}
}
if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
unresolved = 1;
} else if (rule->action == FR_ACT_GOTO)
goto errout_free;
if (rule->l3mdev && rule->table)
goto errout_free;
if (tb[FRA_UID_RANGE]) {
if (current_user_ns() != net->user_ns) {
err = -EPERM;
goto errout_free;
}
rule->uid_range = nla_get_kuid_range(tb);
if (!uid_range_set(&rule->uid_range) ||
!uid_lte(rule->uid_range.start, rule->uid_range.end))
goto errout_free;
} else {
rule->uid_range = fib_kuid_range_unset;
}
if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
rule_exists(ops, frh, tb, rule)) {
err = -EEXIST;
goto errout_free;
}
err = ops->configure(rule, skb, frh, tb);
if (err < 0)
goto errout_free;
list_for_each_entry(r, &ops->rules_list, list) {
if (r->pref > rule->pref)
break;
last = r;
}
fib_rule_get(rule);
if (last)
list_add_rcu(&rule->list, &last->list);
else
list_add_rcu(&rule->list, &ops->rules_list);
if (ops->unresolved_rules) {
/*
* There are unresolved goto rules in the list, check if
* any of them are pointing to this new rule.
*/
list_for_each_entry(r, &ops->rules_list, list) {
if (r->action == FR_ACT_GOTO &&
r->target == rule->pref &&
rtnl_dereference(r->ctarget) == NULL) {
rcu_assign_pointer(r->ctarget, rule);
if (--ops->unresolved_rules == 0)
break;
}
}
}
if (rule->action == FR_ACT_GOTO)
ops->nr_goto_rules++;
if (unresolved)
ops->unresolved_rules++;
if (rule->tun_id)
ip_tunnel_need_metadata();
notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).portid);
flush_route_cache(ops);
rules_ops_put(ops);
return 0;
errout_free:
kfree(rule);
errout:
rules_ops_put(ops);
return err;
}
EXPORT_SYMBOL_GPL(fib_nl_newrule);
int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh)
{
struct net *net = sock_net(skb->sk);
struct fib_rule_hdr *frh = nlmsg_data(nlh);
struct fib_rules_ops *ops = NULL;
struct fib_rule *rule, *tmp;
struct nlattr *tb[FRA_MAX+1];
struct fib_kuid_range range;
int err = -EINVAL;
if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
goto errout;
ops = lookup_rules_ops(net, frh->family);
if (ops == NULL) {
err = -EAFNOSUPPORT;
goto errout;
}
err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
if (err < 0)
goto errout;
err = validate_rulemsg(frh, tb, ops);
if (err < 0)
goto errout;
if (tb[FRA_UID_RANGE]) {
range = nla_get_kuid_range(tb);
if (!uid_range_set(&range))
goto errout;
} else {
range = fib_kuid_range_unset;
}
list_for_each_entry(rule, &ops->rules_list, list) {
if (frh->action && (frh->action != rule->action))
continue;
if (frh_get_table(frh, tb) &&
(frh_get_table(frh, tb) != rule->table))
continue;
if (tb[FRA_PRIORITY] &&
(rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
continue;
if (tb[FRA_IIFNAME] &&
nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
continue;
if (tb[FRA_OIFNAME] &&
nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
continue;
if (tb[FRA_FWMARK] &&
(rule->mark != nla_get_u32(tb[FRA_FWMARK])))
continue;
if (tb[FRA_FWMASK] &&
(rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
continue;
if (tb[FRA_TUN_ID] &&
(rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
continue;
if (tb[FRA_L3MDEV] &&
(rule->l3mdev != nla_get_u8(tb[FRA_L3MDEV])))
continue;
if (uid_range_set(&range) &&
(!uid_eq(rule->uid_range.start, range.start) ||
!uid_eq(rule->uid_range.end, range.end)))
continue;
if (!ops->compare(rule, frh, tb))
continue;
if (rule->flags & FIB_RULE_PERMANENT) {
err = -EPERM;
goto errout;
}
if (ops->delete) {
err = ops->delete(rule);
if (err)
goto errout;
}
if (rule->tun_id)
ip_tunnel_unneed_metadata();
list_del_rcu(&rule->list);
if (rule->action == FR_ACT_GOTO) {
ops->nr_goto_rules--;
if (rtnl_dereference(rule->ctarget) == NULL)
ops->unresolved_rules--;
}
/*
* Check if this rule is a target to any of them. If so,
* disable them. As this operation is eventually very
* expensive, it is only performed if goto rules have
* actually been added.
*/
if (ops->nr_goto_rules > 0) {
list_for_each_entry(tmp, &ops->rules_list, list) {
if (rtnl_dereference(tmp->ctarget) == rule) {
RCU_INIT_POINTER(tmp->ctarget, NULL);
ops->unresolved_rules++;
}
}
}
notify_rule_change(RTM_DELRULE, rule, ops, nlh,
NETLINK_CB(skb).portid);
fib_rule_put(rule);
flush_route_cache(ops);
rules_ops_put(ops);
return 0;
}
err = -ENOENT;
errout:
rules_ops_put(ops);
return err;
}
EXPORT_SYMBOL_GPL(fib_nl_delrule);
static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
struct fib_rule *rule)
{
size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
+ nla_total_size(IFNAMSIZ) /* FRA_IIFNAME */
+ nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */
+ nla_total_size(4) /* FRA_PRIORITY */
+ nla_total_size(4) /* FRA_TABLE */
+ nla_total_size(4) /* FRA_SUPPRESS_PREFIXLEN */
+ nla_total_size(4) /* FRA_SUPPRESS_IFGROUP */
+ nla_total_size(4) /* FRA_FWMARK */
+ nla_total_size(4) /* FRA_FWMASK */
+ nla_total_size_64bit(8) /* FRA_TUN_ID */
+ nla_total_size(sizeof(struct fib_kuid_range));
if (ops->nlmsg_payload)
payload += ops->nlmsg_payload(rule);
return payload;
}
static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
u32 pid, u32 seq, int type, int flags,
struct fib_rules_ops *ops)
{
struct nlmsghdr *nlh;
struct fib_rule_hdr *frh;
nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
if (nlh == NULL)
return -EMSGSIZE;
frh = nlmsg_data(nlh);
frh->family = ops->family;
frh->table = rule->table;
if (nla_put_u32(skb, FRA_TABLE, rule->table))
goto nla_put_failure;
if (nla_put_u32(skb, FRA_SUPPRESS_PREFIXLEN, rule->suppress_prefixlen))
goto nla_put_failure;
frh->res1 = 0;
frh->res2 = 0;
frh->action = rule->action;
frh->flags = rule->flags;
if (rule->action == FR_ACT_GOTO &&
rcu_access_pointer(rule->ctarget) == NULL)
frh->flags |= FIB_RULE_UNRESOLVED;
if (rule->iifname[0]) {
if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
goto nla_put_failure;
if (rule->iifindex == -1)
frh->flags |= FIB_RULE_IIF_DETACHED;
}
if (rule->oifname[0]) {
if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
goto nla_put_failure;
if (rule->oifindex == -1)
frh->flags |= FIB_RULE_OIF_DETACHED;
}
if ((rule->pref &&
nla_put_u32(skb, FRA_PRIORITY, rule->pref)) ||
(rule->mark &&
nla_put_u32(skb, FRA_FWMARK, rule->mark)) ||
((rule->mark_mask || rule->mark) &&
nla_put_u32(skb, FRA_FWMASK, rule->mark_mask)) ||
(rule->target &&
nla_put_u32(skb, FRA_GOTO, rule->target)) ||
(rule->tun_id &&
nla_put_be64(skb, FRA_TUN_ID, rule->tun_id, FRA_PAD)) ||
(rule->l3mdev &&
nla_put_u8(skb, FRA_L3MDEV, rule->l3mdev)) ||
(uid_range_set(&rule->uid_range) &&
nla_put_uid_range(skb, &rule->uid_range)))
goto nla_put_failure;
if (rule->suppress_ifgroup != -1) {
if (nla_put_u32(skb, FRA_SUPPRESS_IFGROUP, rule->suppress_ifgroup))
goto nla_put_failure;
}
if (ops->fill(rule, skb, frh) < 0)
goto nla_put_failure;
nlmsg_end(skb, nlh);
return 0;
nla_put_failure:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
struct fib_rules_ops *ops)
{
int idx = 0;
struct fib_rule *rule;
int err = 0;
rcu_read_lock();
list_for_each_entry_rcu(rule, &ops->rules_list, list) {
if (idx < cb->args[1])
goto skip;
err = fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, RTM_NEWRULE,
NLM_F_MULTI, ops);
if (err)
break;
skip:
idx++;
}
rcu_read_unlock();
cb->args[1] = idx;
rules_ops_put(ops);
return err;
}
static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
struct fib_rules_ops *ops;
int idx = 0, family;
family = rtnl_msg_family(cb->nlh);
if (family != AF_UNSPEC) {
/* Protocol specific dump request */
ops = lookup_rules_ops(net, family);
if (ops == NULL)
return -EAFNOSUPPORT;
dump_rules(skb, cb, ops);
return skb->len;
}
rcu_read_lock();
list_for_each_entry_rcu(ops, &net->rules_ops, list) {
if (idx < cb->args[0] || !try_module_get(ops->owner))
goto skip;
if (dump_rules(skb, cb, ops) < 0)
break;
cb->args[1] = 0;
skip:
idx++;
}
rcu_read_unlock();
cb->args[0] = idx;
return skb->len;
}
static void notify_rule_change(int event, struct fib_rule *rule,
struct fib_rules_ops *ops, struct nlmsghdr *nlh,
u32 pid)
{
struct net *net;
struct sk_buff *skb;
int err = -ENOBUFS;
net = ops->fro_net;
skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
if (skb == NULL)
goto errout;
err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
if (err < 0) {
/* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
WARN_ON(err == -EMSGSIZE);
kfree_skb(skb);
goto errout;
}
rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
return;
errout:
if (err < 0)
rtnl_set_sk_err(net, ops->nlgroup, err);
}
static void attach_rules(struct list_head *rules, struct net_device *dev)
{
struct fib_rule *rule;
list_for_each_entry(rule, rules, list) {
if (rule->iifindex == -1 &&
strcmp(dev->name, rule->iifname) == 0)
rule->iifindex = dev->ifindex;
if (rule->oifindex == -1 &&
strcmp(dev->name, rule->oifname) == 0)
rule->oifindex = dev->ifindex;
}
}
static void detach_rules(struct list_head *rules, struct net_device *dev)
{
struct fib_rule *rule;
list_for_each_entry(rule, rules, list) {
if (rule->iifindex == dev->ifindex)
rule->iifindex = -1;
if (rule->oifindex == dev->ifindex)
rule->oifindex = -1;
}
}
static int fib_rules_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct net *net = dev_net(dev);
struct fib_rules_ops *ops;
ASSERT_RTNL();
switch (event) {
case NETDEV_REGISTER:
list_for_each_entry(ops, &net->rules_ops, list)
attach_rules(&ops->rules_list, dev);
break;
case NETDEV_CHANGENAME:
list_for_each_entry(ops, &net->rules_ops, list) {
detach_rules(&ops->rules_list, dev);
attach_rules(&ops->rules_list, dev);
}
break;
case NETDEV_UNREGISTER:
list_for_each_entry(ops, &net->rules_ops, list)
detach_rules(&ops->rules_list, dev);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block fib_rules_notifier = {
.notifier_call = fib_rules_event,
};
static int __net_init fib_rules_net_init(struct net *net)
{
INIT_LIST_HEAD(&net->rules_ops);
spin_lock_init(&net->rules_mod_lock);
return 0;
}
static struct pernet_operations fib_rules_net_ops = {
.init = fib_rules_net_init,
};
static int __init fib_rules_init(void)
{
int err;
rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL, NULL);
rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL);
rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL);
err = register_pernet_subsys(&fib_rules_net_ops);
if (err < 0)
goto fail;
err = register_netdevice_notifier(&fib_rules_notifier);
if (err < 0)
goto fail_unregister;
return 0;
fail_unregister:
unregister_pernet_subsys(&fib_rules_net_ops);
fail:
rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
return err;
}
subsys_initcall(fib_rules_init);
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