hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

mptcp: refactor token container 

Replace the radix tree with a hash table allocated
at boot time. The radix tree has some shortcoming:
a single lock is contented by all the mptcp operation,
the lookup currently use such lock, and traversing
all the items would require a lock, too.

With hash table instead we trade a little memory to
address all the above - a per bucket lock is used.

To hash the MPTCP sockets, we re-use the msk' sk_node
entry: the MPTCP sockets are never hashed by the stack.
Replace the existing hash proto callbacks with a dummy
implementation, annotating the above constraint.

Additionally refactor the token creation to code to:

- limit the number of consecutive attempts to a fixed
maximum. Hitting a hash bucket with a long chain is
considered a failed attempt

- accept() no longer can fail to token management.

- if token creation fails at connect() time, we do
fallback to TCP (before the connection was closed)

v1 -> v2:
 - fix "no newline at end of file" - Jakub

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2020-06-26 19:30:00 +02:00 committed by David S. Miller
parent d39dceca38
commit 2c5ebd001d
4 changed files with 233 additions and 110 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
net/mptcp/protocol.c
View File

@ -1448,20 +1448,6 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
msk->token = subflow_req->token;
msk->subflow = NULL;
if (unlikely(mptcp_token_new_accept(subflow_req->token, nsk))) {
nsk->sk_state = TCP_CLOSE;
bh_unlock_sock(nsk);
/* we can't call into mptcp_close() here - possible BH context
* free the sock directly.
* sk_clone_lock() sets nsk refcnt to two, hence call sk_free()
* too.
*/
sk_common_release(nsk);
sk_free(nsk);
return NULL;
}
msk->write_seq = subflow_req->idsn + 1;
atomic64_set(&msk->snd_una, msk->write_seq);
if (mp_opt->mp_capable) {
@ -1547,7 +1533,7 @@ static void mptcp_destroy(struct sock *sk)
{
struct mptcp_sock *msk = mptcp_sk(sk);
mptcp_token_destroy(msk->token);
mptcp_token_destroy(msk);
if (msk->cached_ext)
__skb_ext_put(msk->cached_ext);
@ -1636,6 +1622,20 @@ static void mptcp_release_cb(struct sock *sk)
}
}
static int mptcp_hash(struct sock *sk)
{
/* should never be called,
* we hash the TCP subflows not the master socket
*/
WARN_ON_ONCE(1);
return 0;
}
static void mptcp_unhash(struct sock *sk)
{
/* called from sk_common_release(), but nothing to do here */
}
static int mptcp_get_port(struct sock *sk, unsigned short snum)
{
struct mptcp_sock *msk = mptcp_sk(sk);
@ -1679,7 +1679,6 @@ void mptcp_finish_connect(struct sock *ssk)
*/
WRITE_ONCE(msk->remote_key, subflow->remote_key);
WRITE_ONCE(msk->local_key, subflow->local_key);
WRITE_ONCE(msk->token, subflow->token);
WRITE_ONCE(msk->write_seq, subflow->idsn + 1);
WRITE_ONCE(msk->ack_seq, ack_seq);
WRITE_ONCE(msk->can_ack, 1);
@ -1761,8 +1760,8 @@ static struct proto mptcp_prot = {
.sendmsg = mptcp_sendmsg,
.recvmsg = mptcp_recvmsg,
.release_cb = mptcp_release_cb,
.hash = inet_hash,
.unhash = inet_unhash,
.hash = mptcp_hash,
.unhash = mptcp_unhash,
.get_port = mptcp_get_port,
.sockets_allocated = &mptcp_sockets_allocated,
.memory_allocated = &tcp_memory_allocated,
@ -1771,6 +1770,7 @@ static struct proto mptcp_prot = {
.sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem),
.sysctl_mem = sysctl_tcp_mem,
.obj_size = sizeof(struct mptcp_sock),
.slab_flags = SLAB_TYPESAFE_BY_RCU,
.no_autobind = true,
};
@ -1800,6 +1800,7 @@ static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
int addr_len, int flags)
{
struct mptcp_sock *msk = mptcp_sk(sock->sk);
struct mptcp_subflow_context *subflow;
struct socket *ssock;
int err;
@ -1812,19 +1813,23 @@ static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
goto do_connect;
}
mptcp_token_destroy(msk);
ssock = __mptcp_socket_create(msk, TCP_SYN_SENT);
if (IS_ERR(ssock)) {
err = PTR_ERR(ssock);
goto unlock;
}
subflow = mptcp_subflow_ctx(ssock->sk);
#ifdef CONFIG_TCP_MD5SIG
/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
* TCP option space.
*/
if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info))
mptcp_subflow_ctx(ssock->sk)->request_mptcp = 0;
subflow->request_mptcp = 0;
#endif
if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk))
subflow->request_mptcp = 0;
do_connect:
err = ssock->ops->connect(ssock, uaddr, addr_len, flags);
@ -1888,6 +1893,7 @@ static int mptcp_listen(struct socket *sock, int backlog)
pr_debug("msk=%p", msk);
lock_sock(sock->sk);
mptcp_token_destroy(msk);
ssock = __mptcp_socket_create(msk, TCP_LISTEN);
if (IS_ERR(ssock)) {
err = PTR_ERR(ssock);
@ -2086,6 +2092,7 @@ void __init mptcp_proto_init(void)
mptcp_subflow_init();
mptcp_pm_init();
mptcp_token_init();
if (proto_register(&mptcp_prot, 1) != 0)
panic("Failed to register MPTCP proto.\n");

14
net/mptcp/protocol.h
View File

@ -250,6 +250,7 @@ struct mptcp_subflow_request_sock {
u32 local_nonce;
u32 remote_nonce;
struct mptcp_sock *msk;
struct hlist_nulls_node token_node;
};
static inline struct mptcp_subflow_request_sock *
@ -372,12 +373,19 @@ bool mptcp_finish_join(struct sock *sk);
void mptcp_data_acked(struct sock *sk);
void mptcp_subflow_eof(struct sock *sk);
void __init mptcp_token_init(void);
static inline void mptcp_token_init_request(struct request_sock *req)
{
mptcp_subflow_rsk(req)->token_node.pprev = NULL;
}
int mptcp_token_new_request(struct request_sock *req);
void mptcp_token_destroy_request(u32 token);
void mptcp_token_destroy_request(struct request_sock *req);
int mptcp_token_new_connect(struct sock *sk);
int mptcp_token_new_accept(u32 token, struct sock *conn);
void mptcp_token_accept(struct mptcp_subflow_request_sock *r,
struct mptcp_sock *msk);
struct mptcp_sock *mptcp_token_get_sock(u32 token);
void mptcp_token_destroy(u32 token);
void mptcp_token_destroy(struct mptcp_sock *msk);
void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
static inline void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn)

19
net/mptcp/subflow.c
View File

@ -32,12 +32,9 @@ static void SUBFLOW_REQ_INC_STATS(struct request_sock *req,
static int subflow_rebuild_header(struct sock *sk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
int local_id, err = 0;
int local_id;
if (subflow->request_mptcp && !subflow->token) {
pr_debug("subflow=%p", sk);
err = mptcp_token_new_connect(sk);
} else if (subflow->request_join && !subflow->local_nonce) {
if (subflow->request_join && !subflow->local_nonce) {
struct mptcp_sock *msk = (struct mptcp_sock *)subflow->conn;
pr_debug("subflow=%p", sk);
@ -57,9 +54,6 @@ static int subflow_rebuild_header(struct sock *sk)
}
out:
if (err)
return err;
return subflow->icsk_af_ops->rebuild_header(sk);
}
@ -72,8 +66,7 @@ static void subflow_req_destructor(struct request_sock *req)
if (subflow_req->msk)
sock_put((struct sock *)subflow_req->msk);
if (subflow_req->mp_capable)
mptcp_token_destroy_request(subflow_req->token);
mptcp_token_destroy_request(req);
tcp_request_sock_ops.destructor(req);
}
@ -135,6 +128,7 @@ static void subflow_init_req(struct request_sock *req,
subflow_req->mp_capable = 0;
subflow_req->mp_join = 0;
subflow_req->msk = NULL;
mptcp_token_init_request(req);
#ifdef CONFIG_TCP_MD5SIG
/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
@ -250,7 +244,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
subflow->remote_nonce = mp_opt.nonce;
pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
subflow->thmac, subflow->remote_nonce);
} else if (subflow->request_mptcp) {
} else {
tp->is_mptcp = 0;
}
@ -386,7 +380,7 @@ static void mptcp_sock_destruct(struct sock *sk)
sock_orphan(sk);
}
mptcp_token_destroy(mptcp_sk(sk)->token);
mptcp_token_destroy(mptcp_sk(sk));
inet_sock_destruct(sk);
}
@ -505,6 +499,7 @@ create_child:
*/
new_msk->sk_destruct = mptcp_sock_destruct;
mptcp_pm_new_connection(mptcp_sk(new_msk), 1);
mptcp_token_accept(subflow_req, mptcp_sk(new_msk));
ctx->conn = new_msk;
new_msk = NULL;

265
net/mptcp/token.c
View File

@ -24,7 +24,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/radix-tree.h>
#include <linux/memblock.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <net/sock.h>
@ -33,10 +33,55 @@
#include <net/mptcp.h>
#include "protocol.h"
static RADIX_TREE(token_tree, GFP_ATOMIC);
static RADIX_TREE(token_req_tree, GFP_ATOMIC);
static DEFINE_SPINLOCK(token_tree_lock);
static int token_used __read_mostly;
#define TOKEN_MAX_RETRIES 4
#define TOKEN_MAX_CHAIN_LEN 4
struct token_bucket {
spinlock_t lock;
int chain_len;
struct hlist_nulls_head req_chain;
struct hlist_nulls_head msk_chain;
};
static struct token_bucket *token_hash __read_mostly;
static unsigned int token_mask __read_mostly;
static struct token_bucket *token_bucket(u32 token)
{
return &token_hash[token & token_mask];
}
/* called with bucket lock held */
static struct mptcp_subflow_request_sock *
__token_lookup_req(struct token_bucket *t, u32 token)
{
struct mptcp_subflow_request_sock *req;
struct hlist_nulls_node *pos;
hlist_nulls_for_each_entry_rcu(req, pos, &t->req_chain, token_node)
if (req->token == token)
return req;
return NULL;
}
/* called with bucket lock held */
static struct mptcp_sock *
__token_lookup_msk(struct token_bucket *t, u32 token)
{
struct hlist_nulls_node *pos;
struct sock *sk;
sk_nulls_for_each_rcu(sk, pos, &t->msk_chain)
if (mptcp_sk(sk)->token == token)
return mptcp_sk(sk);
return NULL;
}
static bool __token_bucket_busy(struct token_bucket *t, u32 token)
{
return !token || t->chain_len >= TOKEN_MAX_CHAIN_LEN ||
__token_lookup_req(t, token) || __token_lookup_msk(t, token);
}
/**
* mptcp_token_new_request - create new key/idsn/token for subflow_request
@ -52,30 +97,32 @@ static int token_used __read_mostly;
int mptcp_token_new_request(struct request_sock *req)
{
struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
int err;
int retries = TOKEN_MAX_RETRIES;
struct token_bucket *bucket;
u32 token;
while (1) {
u32 token;
again:
mptcp_crypto_key_gen_sha(&subflow_req->local_key,
&subflow_req->token,
&subflow_req->idsn);
pr_debug("req=%p local_key=%llu, token=%u, idsn=%llu\n",
req, subflow_req->local_key, subflow_req->token,
subflow_req->idsn);
mptcp_crypto_key_gen_sha(&subflow_req->local_key,
&subflow_req->token,
&subflow_req->idsn);
pr_debug("req=%p local_key=%llu, token=%u, idsn=%llu\n",
req, subflow_req->local_key, subflow_req->token,
subflow_req->idsn);
token = subflow_req->token;
spin_lock_bh(&token_tree_lock);
if (!radix_tree_lookup(&token_req_tree, token) &&
!radix_tree_lookup(&token_tree, token))
break;
spin_unlock_bh(&token_tree_lock);
token = subflow_req->token;
bucket = token_bucket(token);
spin_lock_bh(&bucket->lock);
if (__token_bucket_busy(bucket, token)) {
spin_unlock_bh(&bucket->lock);
if (!--retries)
return -EBUSY;
goto again;
}
err = radix_tree_insert(&token_req_tree,
subflow_req->token, &token_used);
spin_unlock_bh(&token_tree_lock);
return err;
hlist_nulls_add_head_rcu(&subflow_req->token_node, &bucket->req_chain);
bucket->chain_len++;
spin_unlock_bh(&bucket->lock);
return 0;
}
/**
@ -97,48 +144,56 @@ int mptcp_token_new_request(struct request_sock *req)
int mptcp_token_new_connect(struct sock *sk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct sock *mptcp_sock = subflow->conn;
int err;
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
int retries = TOKEN_MAX_RETRIES;
struct token_bucket *bucket;
while (1) {
u32 token;
pr_debug("ssk=%p, local_key=%llu, token=%u, idsn=%llu\n",
sk, subflow->local_key, subflow->token, subflow->idsn);
mptcp_crypto_key_gen_sha(&subflow->local_key, &subflow->token,
&subflow->idsn);
again:
mptcp_crypto_key_gen_sha(&subflow->local_key, &subflow->token,
&subflow->idsn);
pr_debug("ssk=%p, local_key=%llu, token=%u, idsn=%llu\n",
sk, subflow->local_key, subflow->token, subflow->idsn);
token = subflow->token;
spin_lock_bh(&token_tree_lock);
if (!radix_tree_lookup(&token_req_tree, token) &&
!radix_tree_lookup(&token_tree, token))
break;
spin_unlock_bh(&token_tree_lock);
bucket = token_bucket(subflow->token);
spin_lock_bh(&bucket->lock);
if (__token_bucket_busy(bucket, subflow->token)) {
spin_unlock_bh(&bucket->lock);
if (!--retries)
return -EBUSY;
goto again;
}
err = radix_tree_insert(&token_tree, subflow->token, mptcp_sock);
spin_unlock_bh(&token_tree_lock);
return err;
WRITE_ONCE(msk->token, subflow->token);
__sk_nulls_add_node_rcu((struct sock *)msk, &bucket->msk_chain);
bucket->chain_len++;
spin_unlock_bh(&bucket->lock);
return 0;
}
/**
* mptcp_token_new_accept - insert token for later processing
* @token: the token to insert to the tree
* @conn: the just cloned socket linked to the new connection
* mptcp_token_accept - replace a req sk with full sock in token hash
* @req: the request socket to be removed
* @msk: the just cloned socket linked to the new connection
*
* Called when a SYN packet creates a new logical connection, i.e.
* is not a join request.
*/
int mptcp_token_new_accept(u32 token, struct sock *conn)
void mptcp_token_accept(struct mptcp_subflow_request_sock *req,
struct mptcp_sock *msk)
{
int err;
struct mptcp_subflow_request_sock *pos;
struct token_bucket *bucket;
spin_lock_bh(&token_tree_lock);
err = radix_tree_insert(&token_tree, token, conn);
spin_unlock_bh(&token_tree_lock);
bucket = token_bucket(req->token);
spin_lock_bh(&bucket->lock);
return err;
/* pedantic lookup check for the moved token */
pos = __token_lookup_req(bucket, req->token);
if (!WARN_ON_ONCE(pos != req))
hlist_nulls_del_init_rcu(&req->token_node);
__sk_nulls_add_node_rcu((struct sock *)msk, &bucket->msk_chain);
spin_unlock_bh(&bucket->lock);
}
/**
@ -152,45 +207,103 @@ int mptcp_token_new_accept(u32 token, struct sock *conn)
*/
struct mptcp_sock *mptcp_token_get_sock(u32 token)
{
struct sock *conn;
struct hlist_nulls_node *pos;
struct token_bucket *bucket;
struct mptcp_sock *msk;
struct sock *sk;
spin_lock_bh(&token_tree_lock);
conn = radix_tree_lookup(&token_tree, token);
if (conn) {
/* token still reserved? */
if (conn == (struct sock *)&token_used)
conn = NULL;
else
sock_hold(conn);
rcu_read_lock();
bucket = token_bucket(token);
again:
sk_nulls_for_each_rcu(sk, pos, &bucket->msk_chain) {
msk = mptcp_sk(sk);
if (READ_ONCE(msk->token) != token)
continue;
if (!refcount_inc_not_zero(&sk->sk_refcnt))
goto not_found;
if (READ_ONCE(msk->token) != token) {
sock_put(sk);
goto again;
}
goto found;
}
spin_unlock_bh(&token_tree_lock);
if (get_nulls_value(pos) != (token & token_mask))
goto again;
return mptcp_sk(conn);
not_found:
msk = NULL;
found:
rcu_read_unlock();
return msk;
}
/**
* mptcp_token_destroy_request - remove mptcp connection/token
* @token: token of mptcp connection to remove
* @req: mptcp request socket dropping the token
*
* Remove not-yet-fully-established incoming connection identified
* by @token.
* Remove the token associated to @req.
*/
void mptcp_token_destroy_request(u32 token)
void mptcp_token_destroy_request(struct request_sock *req)
{
spin_lock_bh(&token_tree_lock);
radix_tree_delete(&token_req_tree, token);
spin_unlock_bh(&token_tree_lock);
struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
struct mptcp_subflow_request_sock *pos;
struct token_bucket *bucket;
if (hlist_nulls_unhashed(&subflow_req->token_node))
return;
bucket = token_bucket(subflow_req->token);
spin_lock_bh(&bucket->lock);
pos = __token_lookup_req(bucket, subflow_req->token);
if (!WARN_ON_ONCE(pos != subflow_req)) {
hlist_nulls_del_init_rcu(&pos->token_node);
bucket->chain_len--;
}
spin_unlock_bh(&bucket->lock);
}
/**
* mptcp_token_destroy - remove mptcp connection/token
* @token: token of mptcp connection to remove
* @msk: mptcp connection dropping the token
*
* Remove the connection identified by @token.
* Remove the token associated to @msk
*/
void mptcp_token_destroy(u32 token)
void mptcp_token_destroy(struct mptcp_sock *msk)
{
spin_lock_bh(&token_tree_lock);
radix_tree_delete(&token_tree, token);
spin_unlock_bh(&token_tree_lock);
struct token_bucket *bucket;
struct mptcp_sock *pos;
if (sk_unhashed((struct sock *)msk))
return;
bucket = token_bucket(msk->token);
spin_lock_bh(&bucket->lock);
pos = __token_lookup_msk(bucket, msk->token);
if (!WARN_ON_ONCE(pos != msk)) {
__sk_nulls_del_node_init_rcu((struct sock *)pos);
bucket->chain_len--;
}
spin_unlock_bh(&bucket->lock);
}
void __init mptcp_token_init(void)
{
int i;
token_hash = alloc_large_system_hash("MPTCP token",
sizeof(struct token_bucket),
0,
20,/* one slot per 1MB of memory */
0,
NULL,
&token_mask,
0,
64 * 1024);
for (i = 0; i < token_mask + 1; ++i) {
INIT_HLIST_NULLS_HEAD(&token_hash[i].req_chain, i);
INIT_HLIST_NULLS_HEAD(&token_hash[i].msk_chain, i);
spin_lock_init(&token_hash[i].lock);
}
}