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![Davide Caratti](/assets/img/avatar_default.png)
gcc complains about use of uninitialized 'num'. Fix it by doing the first
assignment of 'num' when the variable is declared.
Fixes: 96d890daad
("mptcp: add msk interations helper")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/49e20da5d467a73414d4294a8bd35e2cb1befd49.1604308087.git.dcaratti@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
411 lines
11 KiB
C
411 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Multipath TCP token management
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* Copyright (c) 2017 - 2019, Intel Corporation.
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*
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* Note: This code is based on mptcp_ctrl.c from multipath-tcp.org,
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* authored by:
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*
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* Sébastien Barré <sebastien.barre@uclouvain.be>
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* Christoph Paasch <christoph.paasch@uclouvain.be>
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* Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi>
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* Gregory Detal <gregory.detal@uclouvain.be>
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* Fabien Duchêne <fabien.duchene@uclouvain.be>
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* Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de>
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* Lavkesh Lahngir <lavkesh51@gmail.com>
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* Andreas Ripke <ripke@neclab.eu>
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* Vlad Dogaru <vlad.dogaru@intel.com>
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* Octavian Purdila <octavian.purdila@intel.com>
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* John Ronan <jronan@tssg.org>
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* Catalin Nicutar <catalin.nicutar@gmail.com>
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* Brandon Heller <brandonh@stanford.edu>
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*/
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#define pr_fmt(fmt) "MPTCP: " fmt
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/memblock.h>
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#include <linux/ip.h>
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#include <linux/tcp.h>
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#include <net/sock.h>
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#include <net/inet_common.h>
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#include <net/protocol.h>
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#include <net/mptcp.h>
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#include "protocol.h"
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#define TOKEN_MAX_RETRIES 4
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#define TOKEN_MAX_CHAIN_LEN 4
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struct token_bucket {
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spinlock_t lock;
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int chain_len;
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struct hlist_nulls_head req_chain;
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struct hlist_nulls_head msk_chain;
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};
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static struct token_bucket *token_hash __read_mostly;
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static unsigned int token_mask __read_mostly;
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static struct token_bucket *token_bucket(u32 token)
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{
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return &token_hash[token & token_mask];
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}
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/* called with bucket lock held */
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static struct mptcp_subflow_request_sock *
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__token_lookup_req(struct token_bucket *t, u32 token)
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{
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struct mptcp_subflow_request_sock *req;
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struct hlist_nulls_node *pos;
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hlist_nulls_for_each_entry_rcu(req, pos, &t->req_chain, token_node)
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if (req->token == token)
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return req;
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return NULL;
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}
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/* called with bucket lock held */
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static struct mptcp_sock *
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__token_lookup_msk(struct token_bucket *t, u32 token)
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{
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struct hlist_nulls_node *pos;
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struct sock *sk;
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sk_nulls_for_each_rcu(sk, pos, &t->msk_chain)
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if (mptcp_sk(sk)->token == token)
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return mptcp_sk(sk);
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return NULL;
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}
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static bool __token_bucket_busy(struct token_bucket *t, u32 token)
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{
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return !token || t->chain_len >= TOKEN_MAX_CHAIN_LEN ||
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__token_lookup_req(t, token) || __token_lookup_msk(t, token);
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}
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static void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn)
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{
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/* we might consider a faster version that computes the key as a
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* hash of some information available in the MPTCP socket. Use
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* random data at the moment, as it's probably the safest option
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* in case multiple sockets are opened in different namespaces at
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* the same time.
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*/
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get_random_bytes(key, sizeof(u64));
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mptcp_crypto_key_sha(*key, token, idsn);
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}
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/**
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* mptcp_token_new_request - create new key/idsn/token for subflow_request
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* @req: the request socket
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*
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* This function is called when a new mptcp connection is coming in.
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*
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* It creates a unique token to identify the new mptcp connection,
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* a secret local key and the initial data sequence number (idsn).
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*
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* Returns 0 on success.
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*/
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int mptcp_token_new_request(struct request_sock *req)
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{
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struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
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struct token_bucket *bucket;
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u32 token;
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mptcp_crypto_key_sha(subflow_req->local_key,
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&subflow_req->token,
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&subflow_req->idsn);
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pr_debug("req=%p local_key=%llu, token=%u, idsn=%llu\n",
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req, subflow_req->local_key, subflow_req->token,
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subflow_req->idsn);
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token = subflow_req->token;
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bucket = token_bucket(token);
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spin_lock_bh(&bucket->lock);
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if (__token_bucket_busy(bucket, token)) {
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spin_unlock_bh(&bucket->lock);
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return -EBUSY;
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}
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hlist_nulls_add_head_rcu(&subflow_req->token_node, &bucket->req_chain);
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bucket->chain_len++;
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spin_unlock_bh(&bucket->lock);
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return 0;
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}
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/**
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* mptcp_token_new_connect - create new key/idsn/token for subflow
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* @sk: the socket that will initiate a connection
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*
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* This function is called when a new outgoing mptcp connection is
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* initiated.
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*
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* It creates a unique token to identify the new mptcp connection,
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* a secret local key and the initial data sequence number (idsn).
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*
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* On success, the mptcp connection can be found again using
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* the computed token at a later time, this is needed to process
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* join requests.
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*
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* returns 0 on success.
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*/
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int mptcp_token_new_connect(struct sock *sk)
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{
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
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struct mptcp_sock *msk = mptcp_sk(subflow->conn);
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int retries = TOKEN_MAX_RETRIES;
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struct token_bucket *bucket;
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pr_debug("ssk=%p, local_key=%llu, token=%u, idsn=%llu\n",
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sk, subflow->local_key, subflow->token, subflow->idsn);
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again:
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mptcp_crypto_key_gen_sha(&subflow->local_key, &subflow->token,
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&subflow->idsn);
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bucket = token_bucket(subflow->token);
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spin_lock_bh(&bucket->lock);
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if (__token_bucket_busy(bucket, subflow->token)) {
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spin_unlock_bh(&bucket->lock);
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if (!--retries)
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return -EBUSY;
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goto again;
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}
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WRITE_ONCE(msk->token, subflow->token);
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__sk_nulls_add_node_rcu((struct sock *)msk, &bucket->msk_chain);
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bucket->chain_len++;
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spin_unlock_bh(&bucket->lock);
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return 0;
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}
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/**
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* mptcp_token_accept - replace a req sk with full sock in token hash
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* @req: the request socket to be removed
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* @msk: the just cloned socket linked to the new connection
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*
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* Called when a SYN packet creates a new logical connection, i.e.
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* is not a join request.
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*/
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void mptcp_token_accept(struct mptcp_subflow_request_sock *req,
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struct mptcp_sock *msk)
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{
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struct mptcp_subflow_request_sock *pos;
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struct token_bucket *bucket;
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bucket = token_bucket(req->token);
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spin_lock_bh(&bucket->lock);
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/* pedantic lookup check for the moved token */
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pos = __token_lookup_req(bucket, req->token);
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if (!WARN_ON_ONCE(pos != req))
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hlist_nulls_del_init_rcu(&req->token_node);
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__sk_nulls_add_node_rcu((struct sock *)msk, &bucket->msk_chain);
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spin_unlock_bh(&bucket->lock);
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}
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bool mptcp_token_exists(u32 token)
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{
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struct hlist_nulls_node *pos;
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struct token_bucket *bucket;
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struct mptcp_sock *msk;
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struct sock *sk;
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rcu_read_lock();
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bucket = token_bucket(token);
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again:
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sk_nulls_for_each_rcu(sk, pos, &bucket->msk_chain) {
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msk = mptcp_sk(sk);
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if (READ_ONCE(msk->token) == token)
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goto found;
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}
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if (get_nulls_value(pos) != (token & token_mask))
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goto again;
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rcu_read_unlock();
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return false;
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found:
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rcu_read_unlock();
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return true;
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}
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/**
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* mptcp_token_get_sock - retrieve mptcp connection sock using its token
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* @token: token of the mptcp connection to retrieve
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*
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* This function returns the mptcp connection structure with the given token.
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* A reference count on the mptcp socket returned is taken.
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*
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* returns NULL if no connection with the given token value exists.
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*/
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struct mptcp_sock *mptcp_token_get_sock(u32 token)
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{
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struct hlist_nulls_node *pos;
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struct token_bucket *bucket;
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struct mptcp_sock *msk;
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struct sock *sk;
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rcu_read_lock();
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bucket = token_bucket(token);
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again:
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sk_nulls_for_each_rcu(sk, pos, &bucket->msk_chain) {
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msk = mptcp_sk(sk);
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if (READ_ONCE(msk->token) != token)
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continue;
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if (!refcount_inc_not_zero(&sk->sk_refcnt))
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goto not_found;
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if (READ_ONCE(msk->token) != token) {
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sock_put(sk);
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goto again;
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}
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goto found;
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}
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if (get_nulls_value(pos) != (token & token_mask))
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goto again;
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not_found:
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msk = NULL;
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found:
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rcu_read_unlock();
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return msk;
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}
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EXPORT_SYMBOL_GPL(mptcp_token_get_sock);
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/**
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* mptcp_token_iter_next - iterate over the token container from given pos
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* @net: namespace to be iterated
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* @s_slot: start slot number
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* @s_num: start number inside the given lock
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*
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* This function returns the first mptcp connection structure found inside the
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* token container starting from the specified position, or NULL.
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*
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* On successful iteration, the iterator is move to the next position and the
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* the acquires a reference to the returned socket.
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*/
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struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
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long *s_num)
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{
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struct mptcp_sock *ret = NULL;
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struct hlist_nulls_node *pos;
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int slot, num = 0;
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for (slot = *s_slot; slot <= token_mask; *s_num = 0, slot++) {
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struct token_bucket *bucket = &token_hash[slot];
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struct sock *sk;
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num = 0;
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if (hlist_nulls_empty(&bucket->msk_chain))
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continue;
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rcu_read_lock();
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sk_nulls_for_each_rcu(sk, pos, &bucket->msk_chain) {
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++num;
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if (!net_eq(sock_net(sk), net))
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continue;
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if (num <= *s_num)
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continue;
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if (!refcount_inc_not_zero(&sk->sk_refcnt))
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continue;
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if (!net_eq(sock_net(sk), net)) {
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sock_put(sk);
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continue;
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}
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ret = mptcp_sk(sk);
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rcu_read_unlock();
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goto out;
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}
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rcu_read_unlock();
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}
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out:
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*s_slot = slot;
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*s_num = num;
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return ret;
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}
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EXPORT_SYMBOL_GPL(mptcp_token_iter_next);
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/**
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* mptcp_token_destroy_request - remove mptcp connection/token
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* @req: mptcp request socket dropping the token
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*
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* Remove the token associated to @req.
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*/
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void mptcp_token_destroy_request(struct request_sock *req)
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{
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struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
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struct mptcp_subflow_request_sock *pos;
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struct token_bucket *bucket;
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if (hlist_nulls_unhashed(&subflow_req->token_node))
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return;
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bucket = token_bucket(subflow_req->token);
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spin_lock_bh(&bucket->lock);
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pos = __token_lookup_req(bucket, subflow_req->token);
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if (!WARN_ON_ONCE(pos != subflow_req)) {
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hlist_nulls_del_init_rcu(&pos->token_node);
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bucket->chain_len--;
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}
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spin_unlock_bh(&bucket->lock);
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}
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/**
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* mptcp_token_destroy - remove mptcp connection/token
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* @msk: mptcp connection dropping the token
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*
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* Remove the token associated to @msk
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*/
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void mptcp_token_destroy(struct mptcp_sock *msk)
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{
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struct token_bucket *bucket;
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struct mptcp_sock *pos;
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if (sk_unhashed((struct sock *)msk))
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return;
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bucket = token_bucket(msk->token);
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spin_lock_bh(&bucket->lock);
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pos = __token_lookup_msk(bucket, msk->token);
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if (!WARN_ON_ONCE(pos != msk)) {
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__sk_nulls_del_node_init_rcu((struct sock *)pos);
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bucket->chain_len--;
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}
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spin_unlock_bh(&bucket->lock);
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}
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void __init mptcp_token_init(void)
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{
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int i;
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token_hash = alloc_large_system_hash("MPTCP token",
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sizeof(struct token_bucket),
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0,
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20,/* one slot per 1MB of memory */
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HASH_ZERO,
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NULL,
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&token_mask,
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0,
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64 * 1024);
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for (i = 0; i < token_mask + 1; ++i) {
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INIT_HLIST_NULLS_HEAD(&token_hash[i].req_chain, i);
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INIT_HLIST_NULLS_HEAD(&token_hash[i].msk_chain, i);
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spin_lock_init(&token_hash[i].lock);
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}
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}
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#if IS_MODULE(CONFIG_MPTCP_KUNIT_TESTS)
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EXPORT_SYMBOL_GPL(mptcp_token_new_request);
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EXPORT_SYMBOL_GPL(mptcp_token_new_connect);
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EXPORT_SYMBOL_GPL(mptcp_token_accept);
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EXPORT_SYMBOL_GPL(mptcp_token_destroy_request);
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EXPORT_SYMBOL_GPL(mptcp_token_destroy);
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#endif
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