mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 21:54:06 +08:00
7126bd5c8b
kernel test robot says:
net/mptcp/syncookies.c: In function 'mptcp_join_cookie_init':
include/linux/kernel.h:47:38: warning: division by zero [-Wdiv-by-zero]
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
I forgot that spinock_t size is 0 on UP, so ARRAY_SIZE cannot be used.
Fixes: 9466a1cceb
("mptcp: enable JOIN requests even if cookies are in use")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
131 lines
3.6 KiB
C
131 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/skbuff.h>
|
|
|
|
#include "protocol.h"
|
|
|
|
/* Syncookies do not work for JOIN requests.
|
|
*
|
|
* Unlike MP_CAPABLE, where the ACK cookie contains the needed MPTCP
|
|
* options to reconstruct the initial syn state, MP_JOIN does not contain
|
|
* the token to obtain the mptcp socket nor the server-generated nonce
|
|
* that was used in the cookie SYN/ACK response.
|
|
*
|
|
* Keep a small best effort state table to store the syn/synack data,
|
|
* indexed by skb hash.
|
|
*
|
|
* A MP_JOIN SYN packet handled by syn cookies is only stored if the 32bit
|
|
* token matches a known mptcp connection that can still accept more subflows.
|
|
*
|
|
* There is no timeout handling -- state is only re-constructed
|
|
* when the TCP ACK passed the cookie validation check.
|
|
*/
|
|
|
|
struct join_entry {
|
|
u32 token;
|
|
u32 remote_nonce;
|
|
u32 local_nonce;
|
|
u8 join_id;
|
|
u8 local_id;
|
|
u8 backup;
|
|
u8 valid;
|
|
};
|
|
|
|
#define COOKIE_JOIN_SLOTS 1024
|
|
|
|
static struct join_entry join_entries[COOKIE_JOIN_SLOTS] __cacheline_aligned_in_smp;
|
|
static spinlock_t join_entry_locks[COOKIE_JOIN_SLOTS] __cacheline_aligned_in_smp;
|
|
|
|
static u32 mptcp_join_entry_hash(struct sk_buff *skb, struct net *net)
|
|
{
|
|
u32 i = skb_get_hash(skb) ^ net_hash_mix(net);
|
|
|
|
return i % ARRAY_SIZE(join_entries);
|
|
}
|
|
|
|
static void mptcp_join_store_state(struct join_entry *entry,
|
|
const struct mptcp_subflow_request_sock *subflow_req)
|
|
{
|
|
entry->token = subflow_req->token;
|
|
entry->remote_nonce = subflow_req->remote_nonce;
|
|
entry->local_nonce = subflow_req->local_nonce;
|
|
entry->backup = subflow_req->backup;
|
|
entry->join_id = subflow_req->remote_id;
|
|
entry->local_id = subflow_req->local_id;
|
|
entry->valid = 1;
|
|
}
|
|
|
|
void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req,
|
|
struct sk_buff *skb)
|
|
{
|
|
struct net *net = read_pnet(&subflow_req->sk.req.ireq_net);
|
|
u32 i = mptcp_join_entry_hash(skb, net);
|
|
|
|
/* No use in waiting if other cpu is already using this slot --
|
|
* would overwrite the data that got stored.
|
|
*/
|
|
spin_lock_bh(&join_entry_locks[i]);
|
|
mptcp_join_store_state(&join_entries[i], subflow_req);
|
|
spin_unlock_bh(&join_entry_locks[i]);
|
|
}
|
|
|
|
/* Called for a cookie-ack with MP_JOIN option present.
|
|
* Look up the saved state based on skb hash & check token matches msk
|
|
* in same netns.
|
|
*
|
|
* Caller will check msk can still accept another subflow. The hmac
|
|
* present in the cookie ACK mptcp option space will be checked later.
|
|
*/
|
|
bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req,
|
|
struct sk_buff *skb)
|
|
{
|
|
struct net *net = read_pnet(&subflow_req->sk.req.ireq_net);
|
|
u32 i = mptcp_join_entry_hash(skb, net);
|
|
struct mptcp_sock *msk;
|
|
struct join_entry *e;
|
|
|
|
e = &join_entries[i];
|
|
|
|
spin_lock_bh(&join_entry_locks[i]);
|
|
|
|
if (e->valid == 0) {
|
|
spin_unlock_bh(&join_entry_locks[i]);
|
|
return false;
|
|
}
|
|
|
|
e->valid = 0;
|
|
|
|
msk = mptcp_token_get_sock(e->token);
|
|
if (!msk) {
|
|
spin_unlock_bh(&join_entry_locks[i]);
|
|
return false;
|
|
}
|
|
|
|
/* If this fails, the token got re-used in the mean time by another
|
|
* mptcp socket in a different netns, i.e. entry is outdated.
|
|
*/
|
|
if (!net_eq(sock_net((struct sock *)msk), net))
|
|
goto err_put;
|
|
|
|
subflow_req->remote_nonce = e->remote_nonce;
|
|
subflow_req->local_nonce = e->local_nonce;
|
|
subflow_req->backup = e->backup;
|
|
subflow_req->remote_id = e->join_id;
|
|
subflow_req->token = e->token;
|
|
subflow_req->msk = msk;
|
|
spin_unlock_bh(&join_entry_locks[i]);
|
|
return true;
|
|
|
|
err_put:
|
|
spin_unlock_bh(&join_entry_locks[i]);
|
|
sock_put((struct sock *)msk);
|
|
return false;
|
|
}
|
|
|
|
void __init mptcp_join_cookie_init(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < COOKIE_JOIN_SLOTS; i++)
|
|
spin_lock_init(&join_entry_locks[i]);
|
|
}
|