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linux/net/ipv4/ipmr_base.c
Michal Kubecek ae0be8de9a netlink: make nla_nest_start() add NLA_F_NESTED flag 
Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.

Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().

Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:

@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)

@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27 17:03:44 -04:00

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/* Linux multicast routing support
* Common logic shared by IPv4 [ipmr] and IPv6 [ip6mr] implementation
*/
#include <linux/rhashtable.h>
#include <linux/mroute_base.h>
/* Sets everything common except 'dev', since that is done under locking */
void vif_device_init(struct vif_device *v,
struct net_device *dev,
unsigned long rate_limit,
unsigned char threshold,
unsigned short flags,
unsigned short get_iflink_mask)
{
v->dev = NULL;
v->bytes_in = 0;
v->bytes_out = 0;
v->pkt_in = 0;
v->pkt_out = 0;
v->rate_limit = rate_limit;
v->flags = flags;
v->threshold = threshold;
if (v->flags & get_iflink_mask)
v->link = dev_get_iflink(dev);
else
v->link = dev->ifindex;
}
EXPORT_SYMBOL(vif_device_init);
struct mr_table *
mr_table_alloc(struct net *net, u32 id,
struct mr_table_ops *ops,
void (*expire_func)(struct timer_list *t),
void (*table_set)(struct mr_table *mrt,
struct net *net))
{
struct mr_table *mrt;
int err;
mrt = kzalloc(sizeof(*mrt), GFP_KERNEL);
if (!mrt)
return ERR_PTR(-ENOMEM);
mrt->id = id;
write_pnet(&mrt->net, net);
mrt->ops = *ops;
err = rhltable_init(&mrt->mfc_hash, mrt->ops.rht_params);
if (err) {
kfree(mrt);
return ERR_PTR(err);
}
INIT_LIST_HEAD(&mrt->mfc_cache_list);
INIT_LIST_HEAD(&mrt->mfc_unres_queue);
timer_setup(&mrt->ipmr_expire_timer, expire_func, 0);
mrt->mroute_reg_vif_num = -1;
table_set(mrt, net);
return mrt;
}
EXPORT_SYMBOL(mr_table_alloc);
void *mr_mfc_find_parent(struct mr_table *mrt, void *hasharg, int parent)
{
struct rhlist_head *tmp, *list;
struct mr_mfc *c;
list = rhltable_lookup(&mrt->mfc_hash, hasharg, *mrt->ops.rht_params);
rhl_for_each_entry_rcu(c, tmp, list, mnode)
if (parent == -1 || parent == c->mfc_parent)
return c;
return NULL;
}
EXPORT_SYMBOL(mr_mfc_find_parent);
void *mr_mfc_find_any_parent(struct mr_table *mrt, int vifi)
{
struct rhlist_head *tmp, *list;
struct mr_mfc *c;
list = rhltable_lookup(&mrt->mfc_hash, mrt->ops.cmparg_any,
*mrt->ops.rht_params);
rhl_for_each_entry_rcu(c, tmp, list, mnode)
if (c->mfc_un.res.ttls[vifi] < 255)
return c;
return NULL;
}
EXPORT_SYMBOL(mr_mfc_find_any_parent);
void *mr_mfc_find_any(struct mr_table *mrt, int vifi, void *hasharg)
{
struct rhlist_head *tmp, *list;
struct mr_mfc *c, *proxy;
list = rhltable_lookup(&mrt->mfc_hash, hasharg, *mrt->ops.rht_params);
rhl_for_each_entry_rcu(c, tmp, list, mnode) {
if (c->mfc_un.res.ttls[vifi] < 255)
return c;
/* It's ok if the vifi is part of the static tree */
proxy = mr_mfc_find_any_parent(mrt, c->mfc_parent);
if (proxy && proxy->mfc_un.res.ttls[vifi] < 255)
return c;
}
return mr_mfc_find_any_parent(mrt, vifi);
}
EXPORT_SYMBOL(mr_mfc_find_any);
#ifdef CONFIG_PROC_FS
void *mr_vif_seq_idx(struct net *net, struct mr_vif_iter *iter, loff_t pos)
{
struct mr_table *mrt = iter->mrt;
for (iter->ct = 0; iter->ct < mrt->maxvif; ++iter->ct) {
if (!VIF_EXISTS(mrt, iter->ct))
continue;
if (pos-- == 0)
return &mrt->vif_table[iter->ct];
}
return NULL;
}
EXPORT_SYMBOL(mr_vif_seq_idx);
void *mr_vif_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct mr_vif_iter *iter = seq->private;
struct net *net = seq_file_net(seq);
struct mr_table *mrt = iter->mrt;
++*pos;
if (v == SEQ_START_TOKEN)
return mr_vif_seq_idx(net, iter, 0);
while (++iter->ct < mrt->maxvif) {
if (!VIF_EXISTS(mrt, iter->ct))
continue;
return &mrt->vif_table[iter->ct];
}
return NULL;
}
EXPORT_SYMBOL(mr_vif_seq_next);
void *mr_mfc_seq_idx(struct net *net,
struct mr_mfc_iter *it, loff_t pos)
{
struct mr_table *mrt = it->mrt;
struct mr_mfc *mfc;
rcu_read_lock();
it->cache = &mrt->mfc_cache_list;
list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
if (pos-- == 0)
return mfc;
rcu_read_unlock();
spin_lock_bh(it->lock);
it->cache = &mrt->mfc_unres_queue;
list_for_each_entry(mfc, it->cache, list)
if (pos-- == 0)
return mfc;
spin_unlock_bh(it->lock);
it->cache = NULL;
return NULL;
}
EXPORT_SYMBOL(mr_mfc_seq_idx);
void *mr_mfc_seq_next(struct seq_file *seq, void *v,
loff_t *pos)
{
struct mr_mfc_iter *it = seq->private;
struct net *net = seq_file_net(seq);
struct mr_table *mrt = it->mrt;
struct mr_mfc *c = v;
++*pos;
if (v == SEQ_START_TOKEN)
return mr_mfc_seq_idx(net, seq->private, 0);
if (c->list.next != it->cache)
return list_entry(c->list.next, struct mr_mfc, list);
if (it->cache == &mrt->mfc_unres_queue)
goto end_of_list;
/* exhausted cache_array, show unresolved */
rcu_read_unlock();
it->cache = &mrt->mfc_unres_queue;
spin_lock_bh(it->lock);
if (!list_empty(it->cache))
return list_first_entry(it->cache, struct mr_mfc, list);
end_of_list:
spin_unlock_bh(it->lock);
it->cache = NULL;
return NULL;
}
EXPORT_SYMBOL(mr_mfc_seq_next);
#endif
int mr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
struct mr_mfc *c, struct rtmsg *rtm)
{
struct rta_mfc_stats mfcs;
struct nlattr *mp_attr;
struct rtnexthop *nhp;
unsigned long lastuse;
int ct;
/* If cache is unresolved, don't try to parse IIF and OIF */
if (c->mfc_parent >= MAXVIFS) {
rtm->rtm_flags |= RTNH_F_UNRESOLVED;
return -ENOENT;
}
if (VIF_EXISTS(mrt, c->mfc_parent) &&
nla_put_u32(skb, RTA_IIF,
mrt->vif_table[c->mfc_parent].dev->ifindex) < 0)
return -EMSGSIZE;
if (c->mfc_flags & MFC_OFFLOAD)
rtm->rtm_flags |= RTNH_F_OFFLOAD;
mp_attr = nla_nest_start_noflag(skb, RTA_MULTIPATH);
if (!mp_attr)
return -EMSGSIZE;
for (ct = c->mfc_un.res.minvif; ct < c->mfc_un.res.maxvif; ct++) {
if (VIF_EXISTS(mrt, ct) && c->mfc_un.res.ttls[ct] < 255) {
struct vif_device *vif;
nhp = nla_reserve_nohdr(skb, sizeof(*nhp));
if (!nhp) {
nla_nest_cancel(skb, mp_attr);
return -EMSGSIZE;
}
nhp->rtnh_flags = 0;
nhp->rtnh_hops = c->mfc_un.res.ttls[ct];
vif = &mrt->vif_table[ct];
nhp->rtnh_ifindex = vif->dev->ifindex;
nhp->rtnh_len = sizeof(*nhp);
}
}
nla_nest_end(skb, mp_attr);
lastuse = READ_ONCE(c->mfc_un.res.lastuse);
lastuse = time_after_eq(jiffies, lastuse) ? jiffies - lastuse : 0;
mfcs.mfcs_packets = c->mfc_un.res.pkt;
mfcs.mfcs_bytes = c->mfc_un.res.bytes;
mfcs.mfcs_wrong_if = c->mfc_un.res.wrong_if;
if (nla_put_64bit(skb, RTA_MFC_STATS, sizeof(mfcs), &mfcs, RTA_PAD) ||
nla_put_u64_64bit(skb, RTA_EXPIRES, jiffies_to_clock_t(lastuse),
RTA_PAD))
return -EMSGSIZE;
rtm->rtm_type = RTN_MULTICAST;
return 1;
}
EXPORT_SYMBOL(mr_fill_mroute);
static bool mr_mfc_uses_dev(const struct mr_table *mrt,
const struct mr_mfc *c,
const struct net_device *dev)
{
int ct;
for (ct = c->mfc_un.res.minvif; ct < c->mfc_un.res.maxvif; ct++) {
if (VIF_EXISTS(mrt, ct) && c->mfc_un.res.ttls[ct] < 255) {
const struct vif_device *vif;
vif = &mrt->vif_table[ct];
if (vif->dev == dev)
return true;
}
}
return false;
}
int mr_table_dump(struct mr_table *mrt, struct sk_buff *skb,
struct netlink_callback *cb,
int (*fill)(struct mr_table *mrt, struct sk_buff *skb,
u32 portid, u32 seq, struct mr_mfc *c,
int cmd, int flags),
spinlock_t *lock, struct fib_dump_filter *filter)
{
unsigned int e = 0, s_e = cb->args[1];
unsigned int flags = NLM_F_MULTI;
struct mr_mfc *mfc;
int err;
if (filter->filter_set)
flags |= NLM_F_DUMP_FILTERED;
list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list) {
if (e < s_e)
goto next_entry;
if (filter->dev &&
!mr_mfc_uses_dev(mrt, mfc, filter->dev))
goto next_entry;
err = fill(mrt, skb, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, mfc, RTM_NEWROUTE, flags);
if (err < 0)
goto out;
next_entry:
e++;
}
spin_lock_bh(lock);
list_for_each_entry(mfc, &mrt->mfc_unres_queue, list) {
if (e < s_e)
goto next_entry2;
if (filter->dev &&
!mr_mfc_uses_dev(mrt, mfc, filter->dev))
goto next_entry2;
err = fill(mrt, skb, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, mfc, RTM_NEWROUTE, flags);
if (err < 0) {
spin_unlock_bh(lock);
goto out;
}
next_entry2:
e++;
}
spin_unlock_bh(lock);
err = 0;
e = 0;
out:
cb->args[1] = e;
return err;
}
EXPORT_SYMBOL(mr_table_dump);
int mr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb,
struct mr_table *(*iter)(struct net *net,
struct mr_table *mrt),
int (*fill)(struct mr_table *mrt,
struct sk_buff *skb,
u32 portid, u32 seq, struct mr_mfc *c,
int cmd, int flags),
spinlock_t *lock, struct fib_dump_filter *filter)
{
unsigned int t = 0, s_t = cb->args[0];
struct net *net = sock_net(skb->sk);
struct mr_table *mrt;
int err;
/* multicast does not track protocol or have route type other
* than RTN_MULTICAST
*/
if (filter->filter_set) {
if (filter->protocol || filter->flags ||
(filter->rt_type && filter->rt_type != RTN_MULTICAST))
return skb->len;
}
rcu_read_lock();
for (mrt = iter(net, NULL); mrt; mrt = iter(net, mrt)) {
if (t < s_t)
goto next_table;
err = mr_table_dump(mrt, skb, cb, fill, lock, filter);
if (err < 0)
break;
next_table:
t++;
}
rcu_read_unlock();
cb->args[0] = t;
return skb->len;
}
EXPORT_SYMBOL(mr_rtm_dumproute);
int mr_dump(struct net *net, struct notifier_block *nb, unsigned short family,
int (*rules_dump)(struct net *net,
struct notifier_block *nb),
struct mr_table *(*mr_iter)(struct net *net,
struct mr_table *mrt),
rwlock_t *mrt_lock)
{
struct mr_table *mrt;
int err;
err = rules_dump(net, nb);
if (err)
return err;
for (mrt = mr_iter(net, NULL); mrt; mrt = mr_iter(net, mrt)) {
struct vif_device *v = &mrt->vif_table[0];
struct mr_mfc *mfc;
int vifi;
/* Notifiy on table VIF entries */
read_lock(mrt_lock);
for (vifi = 0; vifi < mrt->maxvif; vifi++, v++) {
if (!v->dev)
continue;
mr_call_vif_notifier(nb, net, family,
FIB_EVENT_VIF_ADD,
v, vifi, mrt->id);
}
read_unlock(mrt_lock);
/* Notify on table MFC entries */
list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
mr_call_mfc_notifier(nb, net, family,
FIB_EVENT_ENTRY_ADD,
mfc, mrt->id);
}
return 0;
}
EXPORT_SYMBOL(mr_dump);
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