linux/net/netlink/diag.c
Ying Xue c5adde9468 netlink: eliminate nl_sk_hash_lock
As rhashtable_lookup_compare_insert() can guarantee the process
of search and insertion is atomic, it's safe to eliminate the
nl_sk_hash_lock. After this, object insertion or removal will
be protected with per bucket lock on write side while object
lookup is guarded with rcu read lock on read side.

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Cc: Thomas Graf <tgraf@suug.ch>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-13 14:01:00 -05:00

238 lines
5.2 KiB
C

#include <linux/module.h>
#include <net/sock.h>
#include <linux/netlink.h>
#include <linux/sock_diag.h>
#include <linux/netlink_diag.h>
#include <linux/rhashtable.h>
#include "af_netlink.h"
#ifdef CONFIG_NETLINK_MMAP
static int sk_diag_put_ring(struct netlink_ring *ring, int nl_type,
struct sk_buff *nlskb)
{
struct netlink_diag_ring ndr;
ndr.ndr_block_size = ring->pg_vec_pages << PAGE_SHIFT;
ndr.ndr_block_nr = ring->pg_vec_len;
ndr.ndr_frame_size = ring->frame_size;
ndr.ndr_frame_nr = ring->frame_max + 1;
return nla_put(nlskb, nl_type, sizeof(ndr), &ndr);
}
static int sk_diag_put_rings_cfg(struct sock *sk, struct sk_buff *nlskb)
{
struct netlink_sock *nlk = nlk_sk(sk);
int ret;
mutex_lock(&nlk->pg_vec_lock);
ret = sk_diag_put_ring(&nlk->rx_ring, NETLINK_DIAG_RX_RING, nlskb);
if (!ret)
ret = sk_diag_put_ring(&nlk->tx_ring, NETLINK_DIAG_TX_RING,
nlskb);
mutex_unlock(&nlk->pg_vec_lock);
return ret;
}
#else
static int sk_diag_put_rings_cfg(struct sock *sk, struct sk_buff *nlskb)
{
return 0;
}
#endif
static int sk_diag_dump_groups(struct sock *sk, struct sk_buff *nlskb)
{
struct netlink_sock *nlk = nlk_sk(sk);
if (nlk->groups == NULL)
return 0;
return nla_put(nlskb, NETLINK_DIAG_GROUPS, NLGRPSZ(nlk->ngroups),
nlk->groups);
}
static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
struct netlink_diag_req *req,
u32 portid, u32 seq, u32 flags, int sk_ino)
{
struct nlmsghdr *nlh;
struct netlink_diag_msg *rep;
struct netlink_sock *nlk = nlk_sk(sk);
nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),
flags);
if (!nlh)
return -EMSGSIZE;
rep = nlmsg_data(nlh);
rep->ndiag_family = AF_NETLINK;
rep->ndiag_type = sk->sk_type;
rep->ndiag_protocol = sk->sk_protocol;
rep->ndiag_state = sk->sk_state;
rep->ndiag_ino = sk_ino;
rep->ndiag_portid = nlk->portid;
rep->ndiag_dst_portid = nlk->dst_portid;
rep->ndiag_dst_group = nlk->dst_group;
sock_diag_save_cookie(sk, rep->ndiag_cookie);
if ((req->ndiag_show & NDIAG_SHOW_GROUPS) &&
sk_diag_dump_groups(sk, skb))
goto out_nlmsg_trim;
if ((req->ndiag_show & NDIAG_SHOW_MEMINFO) &&
sock_diag_put_meminfo(sk, skb, NETLINK_DIAG_MEMINFO))
goto out_nlmsg_trim;
if ((req->ndiag_show & NDIAG_SHOW_RING_CFG) &&
sk_diag_put_rings_cfg(sk, skb))
goto out_nlmsg_trim;
return nlmsg_end(skb, nlh);
out_nlmsg_trim:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
int protocol, int s_num)
{
struct netlink_table *tbl = &nl_table[protocol];
struct rhashtable *ht = &tbl->hash;
const struct bucket_table *htbl = rht_dereference_rcu(ht->tbl, ht);
struct net *net = sock_net(skb->sk);
struct netlink_diag_req *req;
struct netlink_sock *nlsk;
struct sock *sk;
int ret = 0, num = 0, i;
req = nlmsg_data(cb->nlh);
for (i = 0; i < htbl->size; i++) {
struct rhash_head *pos;
rht_for_each_entry_rcu(nlsk, pos, htbl, i, node) {
sk = (struct sock *)nlsk;
if (!net_eq(sock_net(sk), net))
continue;
if (num < s_num) {
num++;
continue;
}
if (sk_diag_fill(sk, skb, req,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
NLM_F_MULTI,
sock_i_ino(sk)) < 0) {
ret = 1;
goto done;
}
num++;
}
}
sk_for_each_bound(sk, &tbl->mc_list) {
if (sk_hashed(sk))
continue;
if (!net_eq(sock_net(sk), net))
continue;
if (num < s_num) {
num++;
continue;
}
if (sk_diag_fill(sk, skb, req,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
NLM_F_MULTI,
sock_i_ino(sk)) < 0) {
ret = 1;
goto done;
}
num++;
}
done:
cb->args[0] = num;
cb->args[1] = protocol;
return ret;
}
static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
struct netlink_diag_req *req;
int s_num = cb->args[0];
req = nlmsg_data(cb->nlh);
rcu_read_lock();
read_lock(&nl_table_lock);
if (req->sdiag_protocol == NDIAG_PROTO_ALL) {
int i;
for (i = cb->args[1]; i < MAX_LINKS; i++) {
if (__netlink_diag_dump(skb, cb, i, s_num))
break;
s_num = 0;
}
} else {
if (req->sdiag_protocol >= MAX_LINKS) {
read_unlock(&nl_table_lock);
rcu_read_unlock();
return -ENOENT;
}
__netlink_diag_dump(skb, cb, req->sdiag_protocol, s_num);
}
read_unlock(&nl_table_lock);
rcu_read_unlock();
return skb->len;
}
static int netlink_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)
{
int hdrlen = sizeof(struct netlink_diag_req);
struct net *net = sock_net(skb->sk);
if (nlmsg_len(h) < hdrlen)
return -EINVAL;
if (h->nlmsg_flags & NLM_F_DUMP) {
struct netlink_dump_control c = {
.dump = netlink_diag_dump,
};
return netlink_dump_start(net->diag_nlsk, skb, h, &c);
} else
return -EOPNOTSUPP;
}
static const struct sock_diag_handler netlink_diag_handler = {
.family = AF_NETLINK,
.dump = netlink_diag_handler_dump,
};
static int __init netlink_diag_init(void)
{
return sock_diag_register(&netlink_diag_handler);
}
static void __exit netlink_diag_exit(void)
{
sock_diag_unregister(&netlink_diag_handler);
}
module_init(netlink_diag_init);
module_exit(netlink_diag_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 16 /* AF_NETLINK */);