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Message-Id: <1414787651-8499-1-git-send-email-xiyou.wangcong@gmail.com>
Date: Fri, 31 Oct 2014 13:34:11 -0700
From: Cong Wang <xiyou.wangcong@...il.com>
To: netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>,
Cong Wang <xiyou.wangcong@...il.com>
Subject: [Patch net-next] neigh: remove dynamic neigh table registration support
Currently there are only three neigh tables in the whole kernel:
arp table, ndisc table and decnet neigh table. What's more,
we don't support registering multiple tables per family.
Therefore we can just make these tables statically built-in.
Cc: David S. Miller <davem@...emloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
include/net/neighbour.h | 9 +-
net/core/neighbour.c | 249 ++++++++++++++++++++++--------------------------
net/decnet/dn_neigh.c | 2 +-
net/ipv4/arp.c | 2 +-
net/ipv6/ndisc.c | 2 +-
5 files changed, 126 insertions(+), 138 deletions(-)
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index dedfb18..1e65c68 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -220,6 +220,13 @@ struct neigh_table {
struct pneigh_entry **phash_buckets;
};
+enum {
+ NEIGH_ARP_TABLE = 0,
+ NEIGH_ND_TABLE = 1,
+ NEIGH_DN_TABLE = 2,
+ NEIGH_NR_TABLES,
+};
+
static inline int neigh_parms_family(struct neigh_parms *p)
{
return p->tbl->family;
@@ -240,7 +247,7 @@ static inline void *neighbour_priv(const struct neighbour *n)
#define NEIGH_UPDATE_F_ISROUTER 0x40000000
#define NEIGH_UPDATE_F_ADMIN 0x80000000
-void neigh_table_init(struct neigh_table *tbl);
+void neigh_table_init(int index, struct neigh_table *tbl);
int neigh_table_clear(struct neigh_table *tbl);
struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
struct net_device *dev);
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index edd0411..de6831c 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -56,7 +56,6 @@ static void __neigh_notify(struct neighbour *n, int type, int flags);
static void neigh_update_notify(struct neighbour *neigh);
static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
-static struct neigh_table *neigh_tables;
#ifdef CONFIG_PROC_FS
static const struct file_operations neigh_stat_seq_fops;
#endif
@@ -87,13 +86,8 @@ static const struct file_operations neigh_stat_seq_fops;
the most complicated procedure, which we allow is dev->hard_header.
It is supposed, that dev->hard_header is simplistic and does
not make callbacks to neighbour tables.
-
- The last lock is neigh_tbl_lock. It is pure SMP lock, protecting
- list of neighbour tables. This list is used only in process context,
*/
-static DEFINE_RWLOCK(neigh_tbl_lock);
-
static int neigh_blackhole(struct neighbour *neigh, struct sk_buff *skb)
{
kfree_skb(skb);
@@ -1520,11 +1514,15 @@ static void neigh_parms_destroy(struct neigh_parms *parms)
static struct lock_class_key neigh_table_proxy_queue_class;
-static void neigh_table_init_no_netlink(struct neigh_table *tbl)
+static struct neigh_table *neigh_tables[NEIGH_NR_TABLES] __read_mostly;
+
+void neigh_table_init(int index, struct neigh_table *tbl)
{
unsigned long now = jiffies;
unsigned long phsize;
+ neigh_tables[index] = tbl;
+
INIT_LIST_HEAD(&tbl->parms_list);
list_add(&tbl->parms.list, &tbl->parms_list);
write_pnet(&tbl->parms.net, &init_net);
@@ -1566,34 +1564,12 @@ static void neigh_table_init_no_netlink(struct neigh_table *tbl)
tbl->last_flush = now;
tbl->last_rand = now + tbl->parms.reachable_time * 20;
-}
-void neigh_table_init(struct neigh_table *tbl)
-{
- struct neigh_table *tmp;
-
- neigh_table_init_no_netlink(tbl);
- write_lock(&neigh_tbl_lock);
- for (tmp = neigh_tables; tmp; tmp = tmp->next) {
- if (tmp->family == tbl->family)
- break;
- }
- tbl->next = neigh_tables;
- neigh_tables = tbl;
- write_unlock(&neigh_tbl_lock);
-
- if (unlikely(tmp)) {
- pr_err("Registering multiple tables for family %d\n",
- tbl->family);
- dump_stack();
- }
}
EXPORT_SYMBOL(neigh_table_init);
int neigh_table_clear(struct neigh_table *tbl)
{
- struct neigh_table **tp;
-
/* It is not clean... Fix it to unload IPv6 module safely */
cancel_delayed_work_sync(&tbl->gc_work);
del_timer_sync(&tbl->proxy_timer);
@@ -1601,14 +1577,6 @@ int neigh_table_clear(struct neigh_table *tbl)
neigh_ifdown(tbl, NULL);
if (atomic_read(&tbl->entries))
pr_crit("neighbour leakage\n");
- write_lock(&neigh_tbl_lock);
- for (tp = &neigh_tables; *tp; tp = &(*tp)->next) {
- if (*tp == tbl) {
- *tp = tbl->next;
- break;
- }
- }
- write_unlock(&neigh_tbl_lock);
call_rcu(&rcu_dereference_protected(tbl->nht, 1)->rcu,
neigh_hash_free_rcu);
@@ -1626,12 +1594,36 @@ int neigh_table_clear(struct neigh_table *tbl)
}
EXPORT_SYMBOL(neigh_table_clear);
+static struct neigh_table *neigh_find_table(int family)
+{
+ struct neigh_table *tbl = NULL;
+
+ switch (family) {
+ case AF_INET:
+ tbl = neigh_tables[NEIGH_ARP_TABLE];
+ break;
+#if IS_ENABLED(CONFIG_IPV6)
+ case AF_INET6:
+ tbl = neigh_tables[NEIGH_ND_TABLE];
+ break;
+#endif
+#if IS_ENABLED(CONFIG_DECNET)
+ case AF_DECnet:
+ tbl = neigh_tables[NEIGH_DN_TABLE];
+ break;
+#endif
+ }
+
+ return tbl;
+}
+
static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh)
{
struct net *net = sock_net(skb->sk);
struct ndmsg *ndm;
struct nlattr *dst_attr;
struct neigh_table *tbl;
+ struct neighbour *neigh;
struct net_device *dev = NULL;
int err = -EINVAL;
@@ -1652,39 +1644,31 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh)
}
}
- read_lock(&neigh_tbl_lock);
- for (tbl = neigh_tables; tbl; tbl = tbl->next) {
- struct neighbour *neigh;
+ tbl = neigh_find_table(ndm->ndm_family);
+ if (tbl == NULL)
+ return -EAFNOSUPPORT;
- if (tbl->family != ndm->ndm_family)
- continue;
- read_unlock(&neigh_tbl_lock);
-
- if (nla_len(dst_attr) < tbl->key_len)
- goto out;
-
- if (ndm->ndm_flags & NTF_PROXY) {
- err = pneigh_delete(tbl, net, nla_data(dst_attr), dev);
- goto out;
- }
+ if (nla_len(dst_attr) < tbl->key_len)
+ goto out;
- if (dev == NULL)
- goto out;
+ if (ndm->ndm_flags & NTF_PROXY) {
+ err = pneigh_delete(tbl, net, nla_data(dst_attr), dev);
+ goto out;
+ }
- neigh = neigh_lookup(tbl, nla_data(dst_attr), dev);
- if (neigh == NULL) {
- err = -ENOENT;
- goto out;
- }
+ if (dev == NULL)
+ goto out;
- err = neigh_update(neigh, NULL, NUD_FAILED,
- NEIGH_UPDATE_F_OVERRIDE |
- NEIGH_UPDATE_F_ADMIN);
- neigh_release(neigh);
+ neigh = neigh_lookup(tbl, nla_data(dst_attr), dev);
+ if (neigh == NULL) {
+ err = -ENOENT;
goto out;
}
- read_unlock(&neigh_tbl_lock);
- err = -EAFNOSUPPORT;
+
+ err = neigh_update(neigh, NULL, NUD_FAILED,
+ NEIGH_UPDATE_F_OVERRIDE |
+ NEIGH_UPDATE_F_ADMIN);
+ neigh_release(neigh);
out:
return err;
@@ -1692,11 +1676,14 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh)
static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh)
{
+ int flags = NEIGH_UPDATE_F_ADMIN | NEIGH_UPDATE_F_OVERRIDE;
struct net *net = sock_net(skb->sk);
struct ndmsg *ndm;
struct nlattr *tb[NDA_MAX+1];
struct neigh_table *tbl;
struct net_device *dev = NULL;
+ struct neighbour *neigh;
+ void *dst, *lladdr;
int err;
ASSERT_RTNL();
@@ -1720,70 +1707,60 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh)
goto out;
}
- read_lock(&neigh_tbl_lock);
- for (tbl = neigh_tables; tbl; tbl = tbl->next) {
- int flags = NEIGH_UPDATE_F_ADMIN | NEIGH_UPDATE_F_OVERRIDE;
- struct neighbour *neigh;
- void *dst, *lladdr;
+ tbl = neigh_find_table(ndm->ndm_family);
+ if (tbl == NULL)
+ return -EAFNOSUPPORT;
- if (tbl->family != ndm->ndm_family)
- continue;
- read_unlock(&neigh_tbl_lock);
+ if (nla_len(tb[NDA_DST]) < tbl->key_len)
+ goto out;
+ dst = nla_data(tb[NDA_DST]);
+ lladdr = tb[NDA_LLADDR] ? nla_data(tb[NDA_LLADDR]) : NULL;
- if (nla_len(tb[NDA_DST]) < tbl->key_len)
- goto out;
- dst = nla_data(tb[NDA_DST]);
- lladdr = tb[NDA_LLADDR] ? nla_data(tb[NDA_LLADDR]) : NULL;
+ if (ndm->ndm_flags & NTF_PROXY) {
+ struct pneigh_entry *pn;
- if (ndm->ndm_flags & NTF_PROXY) {
- struct pneigh_entry *pn;
+ err = -ENOBUFS;
+ pn = pneigh_lookup(tbl, net, dst, dev, 1);
+ if (pn) {
+ pn->flags = ndm->ndm_flags;
+ err = 0;
+ }
+ goto out;
+ }
- err = -ENOBUFS;
- pn = pneigh_lookup(tbl, net, dst, dev, 1);
- if (pn) {
- pn->flags = ndm->ndm_flags;
- err = 0;
- }
+ if (dev == NULL)
+ goto out;
+
+ neigh = neigh_lookup(tbl, dst, dev);
+ if (neigh == NULL) {
+ if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
+ err = -ENOENT;
goto out;
}
- if (dev == NULL)
+ neigh = __neigh_lookup_errno(tbl, dst, dev);
+ if (IS_ERR(neigh)) {
+ err = PTR_ERR(neigh);
+ goto out;
+ }
+ } else {
+ if (nlh->nlmsg_flags & NLM_F_EXCL) {
+ err = -EEXIST;
+ neigh_release(neigh);
goto out;
-
- neigh = neigh_lookup(tbl, dst, dev);
- if (neigh == NULL) {
- if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
- err = -ENOENT;
- goto out;
- }
-
- neigh = __neigh_lookup_errno(tbl, dst, dev);
- if (IS_ERR(neigh)) {
- err = PTR_ERR(neigh);
- goto out;
- }
- } else {
- if (nlh->nlmsg_flags & NLM_F_EXCL) {
- err = -EEXIST;
- neigh_release(neigh);
- goto out;
- }
-
- if (!(nlh->nlmsg_flags & NLM_F_REPLACE))
- flags &= ~NEIGH_UPDATE_F_OVERRIDE;
}
- if (ndm->ndm_flags & NTF_USE) {
- neigh_event_send(neigh, NULL);
- err = 0;
- } else
- err = neigh_update(neigh, lladdr, ndm->ndm_state, flags);
- neigh_release(neigh);
- goto out;
+ if (!(nlh->nlmsg_flags & NLM_F_REPLACE))
+ flags &= ~NEIGH_UPDATE_F_OVERRIDE;
}
- read_unlock(&neigh_tbl_lock);
- err = -EAFNOSUPPORT;
+ if (ndm->ndm_flags & NTF_USE) {
+ neigh_event_send(neigh, NULL);
+ err = 0;
+ } else
+ err = neigh_update(neigh, lladdr, ndm->ndm_state, flags);
+ neigh_release(neigh);
+
out:
return err;
}
@@ -1982,7 +1959,8 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh)
struct neigh_table *tbl;
struct ndtmsg *ndtmsg;
struct nlattr *tb[NDTA_MAX+1];
- int err;
+ bool found = false;
+ int err, tidx;
err = nlmsg_parse(nlh, sizeof(*ndtmsg), tb, NDTA_MAX,
nl_neightbl_policy);
@@ -1995,19 +1973,21 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh)
}
ndtmsg = nlmsg_data(nlh);
- read_lock(&neigh_tbl_lock);
- for (tbl = neigh_tables; tbl; tbl = tbl->next) {
+
+ for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
+ tbl = neigh_tables[tidx];
+ if (!tbl)
+ continue;
if (ndtmsg->ndtm_family && tbl->family != ndtmsg->ndtm_family)
continue;
-
- if (nla_strcmp(tb[NDTA_NAME], tbl->id) == 0)
+ if (nla_strcmp(tb[NDTA_NAME], tbl->id) == 0) {
+ found = true;
break;
+ }
}
- if (tbl == NULL) {
- err = -ENOENT;
- goto errout_locked;
- }
+ if (!found)
+ return -ENOENT;
/*
* We acquire tbl->lock to be nice to the periodic timers and
@@ -2118,8 +2098,6 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh)
errout_tbl_lock:
write_unlock_bh(&tbl->lock);
-errout_locked:
- read_unlock(&neigh_tbl_lock);
errout:
return err;
}
@@ -2134,10 +2112,13 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
- read_lock(&neigh_tbl_lock);
- for (tbl = neigh_tables, tidx = 0; tbl; tbl = tbl->next, tidx++) {
+ for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
struct neigh_parms *p;
+ tbl = neigh_tables[tidx];
+ if (!tbl)
+ continue;
+
if (tidx < tbl_skip || (family && tbl->family != family))
continue;
@@ -2168,7 +2149,6 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
neigh_skip = 0;
}
out:
- read_unlock(&neigh_tbl_lock);
cb->args[0] = tidx;
cb->args[1] = nidx;
@@ -2351,7 +2331,6 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
int proxy = 0;
int err;
- read_lock(&neigh_tbl_lock);
family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
/* check for full ndmsg structure presence, family member is
@@ -2363,8 +2342,11 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
s_t = cb->args[0];
- for (tbl = neigh_tables, t = 0; tbl;
- tbl = tbl->next, t++) {
+ for (t = 0; t < NEIGH_NR_TABLES; t++) {
+ tbl = neigh_tables[t];
+
+ if (!tbl)
+ continue;
if (t < s_t || (family && tbl->family != family))
continue;
if (t > s_t)
@@ -2377,7 +2359,6 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
if (err < 0)
break;
}
- read_unlock(&neigh_tbl_lock);
cb->args[0] = t;
return skb->len;
diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
index c8121ce..845957a 100644
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -591,7 +591,7 @@ static const struct file_operations dn_neigh_seq_fops = {
void __init dn_neigh_init(void)
{
- neigh_table_init(&dn_neigh_table);
+ neigh_table_init(NEIGH_DN_TABLE, &dn_neigh_table);
proc_create("decnet_neigh", S_IRUGO, init_net.proc_net,
&dn_neigh_seq_fops);
}
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 16acb59..205e147 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -1292,7 +1292,7 @@ static int arp_proc_init(void);
void __init arp_init(void)
{
- neigh_table_init(&arp_tbl);
+ neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
dev_add_pack(&arp_packet_type);
arp_proc_init();
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 4cb45c1..c67f339 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1763,7 +1763,7 @@ int __init ndisc_init(void)
/*
* Initialize the neighbour table
*/
- neigh_table_init(&nd_tbl);
+ neigh_table_init(NEIGH_ND_TABLE, &nd_tbl);
#ifdef CONFIG_SYSCTL
err = neigh_sysctl_register(NULL, &nd_tbl.parms,
--
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