linux/net/ipv6/ila/ila_xlat.c
Tom Herbert 97a6ec4ac0 rhashtable: Change rhashtable_walk_start to return void
Most callers of rhashtable_walk_start don't care about a resize event
which is indicated by a return value of -EAGAIN. So calls to
rhashtable_walk_start are wrapped wih code to ignore -EAGAIN. Something
like this is common:

       ret = rhashtable_walk_start(rhiter);
       if (ret && ret != -EAGAIN)
               goto out;

Since zero and -EAGAIN are the only possible return values from the
function this check is pointless. The condition never evaluates to true.

This patch changes rhashtable_walk_start to return void. This simplifies
code for the callers that ignore -EAGAIN. For the few cases where the
caller cares about the resize event, particularly where the table can be
walked in mulitple parts for netlink or seq file dump, the function
rhashtable_walk_start_check has been added that returns -EAGAIN on a
resize event.

Signed-off-by: Tom Herbert <tom@quantonium.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-11 09:58:38 -05:00

669 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/jhash.h>
#include <linux/netfilter.h>
#include <linux/rcupdate.h>
#include <linux/rhashtable.h>
#include <linux/vmalloc.h>
#include <net/genetlink.h>
#include <net/ila.h>
#include <net/netns/generic.h>
#include <uapi/linux/genetlink.h>
#include "ila.h"
struct ila_xlat_params {
struct ila_params ip;
int ifindex;
};
struct ila_map {
struct ila_xlat_params xp;
struct rhash_head node;
struct ila_map __rcu *next;
struct rcu_head rcu;
};
static unsigned int ila_net_id;
struct ila_net {
struct rhashtable rhash_table;
spinlock_t *locks; /* Bucket locks for entry manipulation */
unsigned int locks_mask;
bool hooks_registered;
};
#define LOCKS_PER_CPU 10
static int alloc_ila_locks(struct ila_net *ilan)
{
unsigned int i, size;
unsigned int nr_pcpus = num_possible_cpus();
nr_pcpus = min_t(unsigned int, nr_pcpus, 32UL);
size = roundup_pow_of_two(nr_pcpus * LOCKS_PER_CPU);
if (sizeof(spinlock_t) != 0) {
ilan->locks = kvmalloc(size * sizeof(spinlock_t), GFP_KERNEL);
if (!ilan->locks)
return -ENOMEM;
for (i = 0; i < size; i++)
spin_lock_init(&ilan->locks[i]);
}
ilan->locks_mask = size - 1;
return 0;
}
static u32 hashrnd __read_mostly;
static __always_inline void __ila_hash_secret_init(void)
{
net_get_random_once(&hashrnd, sizeof(hashrnd));
}
static inline u32 ila_locator_hash(struct ila_locator loc)
{
u32 *v = (u32 *)loc.v32;
__ila_hash_secret_init();
return jhash_2words(v[0], v[1], hashrnd);
}
static inline spinlock_t *ila_get_lock(struct ila_net *ilan,
struct ila_locator loc)
{
return &ilan->locks[ila_locator_hash(loc) & ilan->locks_mask];
}
static inline int ila_cmp_wildcards(struct ila_map *ila,
struct ila_addr *iaddr, int ifindex)
{
return (ila->xp.ifindex && ila->xp.ifindex != ifindex);
}
static inline int ila_cmp_params(struct ila_map *ila,
struct ila_xlat_params *xp)
{
return (ila->xp.ifindex != xp->ifindex);
}
static int ila_cmpfn(struct rhashtable_compare_arg *arg,
const void *obj)
{
const struct ila_map *ila = obj;
return (ila->xp.ip.locator_match.v64 != *(__be64 *)arg->key);
}
static inline int ila_order(struct ila_map *ila)
{
int score = 0;
if (ila->xp.ifindex)
score += 1 << 1;
return score;
}
static const struct rhashtable_params rht_params = {
.nelem_hint = 1024,
.head_offset = offsetof(struct ila_map, node),
.key_offset = offsetof(struct ila_map, xp.ip.locator_match),
.key_len = sizeof(u64), /* identifier */
.max_size = 1048576,
.min_size = 256,
.automatic_shrinking = true,
.obj_cmpfn = ila_cmpfn,
};
static struct genl_family ila_nl_family;
static const struct nla_policy ila_nl_policy[ILA_ATTR_MAX + 1] = {
[ILA_ATTR_LOCATOR] = { .type = NLA_U64, },
[ILA_ATTR_LOCATOR_MATCH] = { .type = NLA_U64, },
[ILA_ATTR_IFINDEX] = { .type = NLA_U32, },
[ILA_ATTR_CSUM_MODE] = { .type = NLA_U8, },
[ILA_ATTR_IDENT_TYPE] = { .type = NLA_U8, },
};
static int parse_nl_config(struct genl_info *info,
struct ila_xlat_params *xp)
{
memset(xp, 0, sizeof(*xp));
if (info->attrs[ILA_ATTR_LOCATOR])
xp->ip.locator.v64 = (__force __be64)nla_get_u64(
info->attrs[ILA_ATTR_LOCATOR]);
if (info->attrs[ILA_ATTR_LOCATOR_MATCH])
xp->ip.locator_match.v64 = (__force __be64)nla_get_u64(
info->attrs[ILA_ATTR_LOCATOR_MATCH]);
if (info->attrs[ILA_ATTR_CSUM_MODE])
xp->ip.csum_mode = nla_get_u8(info->attrs[ILA_ATTR_CSUM_MODE]);
else
xp->ip.csum_mode = ILA_CSUM_NO_ACTION;
if (info->attrs[ILA_ATTR_IDENT_TYPE])
xp->ip.ident_type = nla_get_u8(
info->attrs[ILA_ATTR_IDENT_TYPE]);
else
xp->ip.ident_type = ILA_ATYPE_USE_FORMAT;
if (info->attrs[ILA_ATTR_IFINDEX])
xp->ifindex = nla_get_s32(info->attrs[ILA_ATTR_IFINDEX]);
return 0;
}
/* Must be called with rcu readlock */
static inline struct ila_map *ila_lookup_wildcards(struct ila_addr *iaddr,
int ifindex,
struct ila_net *ilan)
{
struct ila_map *ila;
ila = rhashtable_lookup_fast(&ilan->rhash_table, &iaddr->loc,
rht_params);
while (ila) {
if (!ila_cmp_wildcards(ila, iaddr, ifindex))
return ila;
ila = rcu_access_pointer(ila->next);
}
return NULL;
}
/* Must be called with rcu readlock */
static inline struct ila_map *ila_lookup_by_params(struct ila_xlat_params *xp,
struct ila_net *ilan)
{
struct ila_map *ila;
ila = rhashtable_lookup_fast(&ilan->rhash_table,
&xp->ip.locator_match,
rht_params);
while (ila) {
if (!ila_cmp_params(ila, xp))
return ila;
ila = rcu_access_pointer(ila->next);
}
return NULL;
}
static inline void ila_release(struct ila_map *ila)
{
kfree_rcu(ila, rcu);
}
static void ila_free_cb(void *ptr, void *arg)
{
struct ila_map *ila = (struct ila_map *)ptr, *next;
/* Assume rcu_readlock held */
while (ila) {
next = rcu_access_pointer(ila->next);
ila_release(ila);
ila = next;
}
}
static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila);
static unsigned int
ila_nf_input(void *priv,
struct sk_buff *skb,
const struct nf_hook_state *state)
{
ila_xlat_addr(skb, false);
return NF_ACCEPT;
}
static const struct nf_hook_ops ila_nf_hook_ops[] = {
{
.hook = ila_nf_input,
.pf = NFPROTO_IPV6,
.hooknum = NF_INET_PRE_ROUTING,
.priority = -1,
},
};
static int ila_add_mapping(struct net *net, struct ila_xlat_params *xp)
{
struct ila_net *ilan = net_generic(net, ila_net_id);
struct ila_map *ila, *head;
spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
int err = 0, order;
if (!ilan->hooks_registered) {
/* We defer registering net hooks in the namespace until the
* first mapping is added.
*/
err = nf_register_net_hooks(net, ila_nf_hook_ops,
ARRAY_SIZE(ila_nf_hook_ops));
if (err)
return err;
ilan->hooks_registered = true;
}
ila = kzalloc(sizeof(*ila), GFP_KERNEL);
if (!ila)
return -ENOMEM;
ila_init_saved_csum(&xp->ip);
ila->xp = *xp;
order = ila_order(ila);
spin_lock(lock);
head = rhashtable_lookup_fast(&ilan->rhash_table,
&xp->ip.locator_match,
rht_params);
if (!head) {
/* New entry for the rhash_table */
err = rhashtable_lookup_insert_fast(&ilan->rhash_table,
&ila->node, rht_params);
} else {
struct ila_map *tila = head, *prev = NULL;
do {
if (!ila_cmp_params(tila, xp)) {
err = -EEXIST;
goto out;
}
if (order > ila_order(tila))
break;
prev = tila;
tila = rcu_dereference_protected(tila->next,
lockdep_is_held(lock));
} while (tila);
if (prev) {
/* Insert in sub list of head */
RCU_INIT_POINTER(ila->next, tila);
rcu_assign_pointer(prev->next, ila);
} else {
/* Make this ila new head */
RCU_INIT_POINTER(ila->next, head);
err = rhashtable_replace_fast(&ilan->rhash_table,
&head->node,
&ila->node, rht_params);
if (err)
goto out;
}
}
out:
spin_unlock(lock);
if (err)
kfree(ila);
return err;
}
static int ila_del_mapping(struct net *net, struct ila_xlat_params *xp)
{
struct ila_net *ilan = net_generic(net, ila_net_id);
struct ila_map *ila, *head, *prev;
spinlock_t *lock = ila_get_lock(ilan, xp->ip.locator_match);
int err = -ENOENT;
spin_lock(lock);
head = rhashtable_lookup_fast(&ilan->rhash_table,
&xp->ip.locator_match, rht_params);
ila = head;
prev = NULL;
while (ila) {
if (ila_cmp_params(ila, xp)) {
prev = ila;
ila = rcu_dereference_protected(ila->next,
lockdep_is_held(lock));
continue;
}
err = 0;
if (prev) {
/* Not head, just delete from list */
rcu_assign_pointer(prev->next, ila->next);
} else {
/* It is the head. If there is something in the
* sublist we need to make a new head.
*/
head = rcu_dereference_protected(ila->next,
lockdep_is_held(lock));
if (head) {
/* Put first entry in the sublist into the
* table
*/
err = rhashtable_replace_fast(
&ilan->rhash_table, &ila->node,
&head->node, rht_params);
if (err)
goto out;
} else {
/* Entry no longer used */
err = rhashtable_remove_fast(&ilan->rhash_table,
&ila->node,
rht_params);
}
}
ila_release(ila);
break;
}
out:
spin_unlock(lock);
return err;
}
static int ila_nl_cmd_add_mapping(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
struct ila_xlat_params p;
int err;
err = parse_nl_config(info, &p);
if (err)
return err;
return ila_add_mapping(net, &p);
}
static int ila_nl_cmd_del_mapping(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
struct ila_xlat_params xp;
int err;
err = parse_nl_config(info, &xp);
if (err)
return err;
ila_del_mapping(net, &xp);
return 0;
}
static int ila_fill_info(struct ila_map *ila, struct sk_buff *msg)
{
if (nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR,
(__force u64)ila->xp.ip.locator.v64,
ILA_ATTR_PAD) ||
nla_put_u64_64bit(msg, ILA_ATTR_LOCATOR_MATCH,
(__force u64)ila->xp.ip.locator_match.v64,
ILA_ATTR_PAD) ||
nla_put_s32(msg, ILA_ATTR_IFINDEX, ila->xp.ifindex) ||
nla_put_u8(msg, ILA_ATTR_CSUM_MODE, ila->xp.ip.csum_mode) ||
nla_put_u8(msg, ILA_ATTR_IDENT_TYPE, ila->xp.ip.ident_type))
return -1;
return 0;
}
static int ila_dump_info(struct ila_map *ila,
u32 portid, u32 seq, u32 flags,
struct sk_buff *skb, u8 cmd)
{
void *hdr;
hdr = genlmsg_put(skb, portid, seq, &ila_nl_family, flags, cmd);
if (!hdr)
return -ENOMEM;
if (ila_fill_info(ila, skb) < 0)
goto nla_put_failure;
genlmsg_end(skb, hdr);
return 0;
nla_put_failure:
genlmsg_cancel(skb, hdr);
return -EMSGSIZE;
}
static int ila_nl_cmd_get_mapping(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
struct ila_net *ilan = net_generic(net, ila_net_id);
struct sk_buff *msg;
struct ila_xlat_params xp;
struct ila_map *ila;
int ret;
ret = parse_nl_config(info, &xp);
if (ret)
return ret;
msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (!msg)
return -ENOMEM;
rcu_read_lock();
ila = ila_lookup_by_params(&xp, ilan);
if (ila) {
ret = ila_dump_info(ila,
info->snd_portid,
info->snd_seq, 0, msg,
info->genlhdr->cmd);
}
rcu_read_unlock();
if (ret < 0)
goto out_free;
return genlmsg_reply(msg, info);
out_free:
nlmsg_free(msg);
return ret;
}
struct ila_dump_iter {
struct rhashtable_iter rhiter;
};
static int ila_nl_dump_start(struct netlink_callback *cb)
{
struct net *net = sock_net(cb->skb->sk);
struct ila_net *ilan = net_generic(net, ila_net_id);
struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
if (!iter) {
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
return -ENOMEM;
cb->args[0] = (long)iter;
}
return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter,
GFP_KERNEL);
}
static int ila_nl_dump_done(struct netlink_callback *cb)
{
struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
rhashtable_walk_exit(&iter->rhiter);
kfree(iter);
return 0;
}
static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
struct rhashtable_iter *rhiter = &iter->rhiter;
struct ila_map *ila;
int ret;
rhashtable_walk_start(rhiter);
for (;;) {
ila = rhashtable_walk_next(rhiter);
if (IS_ERR(ila)) {
if (PTR_ERR(ila) == -EAGAIN)
continue;
ret = PTR_ERR(ila);
goto done;
} else if (!ila) {
break;
}
while (ila) {
ret = ila_dump_info(ila, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, NLM_F_MULTI,
skb, ILA_CMD_GET);
if (ret)
goto done;
ila = rcu_access_pointer(ila->next);
}
}
ret = skb->len;
done:
rhashtable_walk_stop(rhiter);
return ret;
}
static const struct genl_ops ila_nl_ops[] = {
{
.cmd = ILA_CMD_ADD,
.doit = ila_nl_cmd_add_mapping,
.policy = ila_nl_policy,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = ILA_CMD_DEL,
.doit = ila_nl_cmd_del_mapping,
.policy = ila_nl_policy,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = ILA_CMD_GET,
.doit = ila_nl_cmd_get_mapping,
.start = ila_nl_dump_start,
.dumpit = ila_nl_dump,
.done = ila_nl_dump_done,
.policy = ila_nl_policy,
},
};
static struct genl_family ila_nl_family __ro_after_init = {
.hdrsize = 0,
.name = ILA_GENL_NAME,
.version = ILA_GENL_VERSION,
.maxattr = ILA_ATTR_MAX,
.netnsok = true,
.parallel_ops = true,
.module = THIS_MODULE,
.ops = ila_nl_ops,
.n_ops = ARRAY_SIZE(ila_nl_ops),
};
#define ILA_HASH_TABLE_SIZE 1024
static __net_init int ila_init_net(struct net *net)
{
int err;
struct ila_net *ilan = net_generic(net, ila_net_id);
err = alloc_ila_locks(ilan);
if (err)
return err;
rhashtable_init(&ilan->rhash_table, &rht_params);
return 0;
}
static __net_exit void ila_exit_net(struct net *net)
{
struct ila_net *ilan = net_generic(net, ila_net_id);
rhashtable_free_and_destroy(&ilan->rhash_table, ila_free_cb, NULL);
kvfree(ilan->locks);
if (ilan->hooks_registered)
nf_unregister_net_hooks(net, ila_nf_hook_ops,
ARRAY_SIZE(ila_nf_hook_ops));
}
static struct pernet_operations ila_net_ops = {
.init = ila_init_net,
.exit = ila_exit_net,
.id = &ila_net_id,
.size = sizeof(struct ila_net),
};
static int ila_xlat_addr(struct sk_buff *skb, bool sir2ila)
{
struct ila_map *ila;
struct ipv6hdr *ip6h = ipv6_hdr(skb);
struct net *net = dev_net(skb->dev);
struct ila_net *ilan = net_generic(net, ila_net_id);
struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
/* Assumes skb contains a valid IPv6 header that is pulled */
/* No check here that ILA type in the mapping matches what is in the
* address. We assume that whatever sender gaves us can be translated.
* The checksum mode however is relevant.
*/
rcu_read_lock();
ila = ila_lookup_wildcards(iaddr, skb->dev->ifindex, ilan);
if (ila)
ila_update_ipv6_locator(skb, &ila->xp.ip, sir2ila);
rcu_read_unlock();
return 0;
}
int __init ila_xlat_init(void)
{
int ret;
ret = register_pernet_device(&ila_net_ops);
if (ret)
goto exit;
ret = genl_register_family(&ila_nl_family);
if (ret < 0)
goto unregister;
return 0;
unregister:
unregister_pernet_device(&ila_net_ops);
exit:
return ret;
}
void ila_xlat_fini(void)
{
genl_unregister_family(&ila_nl_family);
unregister_pernet_device(&ila_net_ops);
}