From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- net/mptcp/token.c | 422 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 422 insertions(+) create mode 100644 net/mptcp/token.c (limited to 'net/mptcp/token.c') diff --git a/net/mptcp/token.c b/net/mptcp/token.c new file mode 100644 index 0000000000..5bb9245343 --- /dev/null +++ b/net/mptcp/token.c @@ -0,0 +1,422 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Multipath TCP token management + * Copyright (c) 2017 - 2019, Intel Corporation. + * + * Note: This code is based on mptcp_ctrl.c from multipath-tcp.org, + * authored by: + * + * Sébastien Barré + * Christoph Paasch + * Jaakko Korkeaniemi + * Gregory Detal + * Fabien Duchêne + * Andreas Seelinger + * Lavkesh Lahngir + * Andreas Ripke + * Vlad Dogaru + * Octavian Purdila + * John Ronan + * Catalin Nicutar + * Brandon Heller + */ + +#define pr_fmt(fmt) "MPTCP: " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "protocol.h" + +#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); +} + +static void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn) +{ + /* we might consider a faster version that computes the key as a + * hash of some information available in the MPTCP socket. Use + * random data at the moment, as it's probably the safest option + * in case multiple sockets are opened in different namespaces at + * the same time. + */ + get_random_bytes(key, sizeof(u64)); + mptcp_crypto_key_sha(*key, token, idsn); +} + +/** + * mptcp_token_new_request - create new key/idsn/token for subflow_request + * @req: the request socket + * + * This function is called when a new mptcp connection is coming in. + * + * It creates a unique token to identify the new mptcp connection, + * a secret local key and the initial data sequence number (idsn). + * + * Returns 0 on success. + */ +int mptcp_token_new_request(struct request_sock *req) +{ + struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); + struct token_bucket *bucket; + u32 token; + + mptcp_crypto_key_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; + bucket = token_bucket(token); + spin_lock_bh(&bucket->lock); + if (__token_bucket_busy(bucket, token)) { + spin_unlock_bh(&bucket->lock); + return -EBUSY; + } + + hlist_nulls_add_head_rcu(&subflow_req->token_node, &bucket->req_chain); + bucket->chain_len++; + spin_unlock_bh(&bucket->lock); + return 0; +} + +/** + * mptcp_token_new_connect - create new key/idsn/token for subflow + * @ssk: the socket that will initiate a connection + * + * This function is called when a new outgoing mptcp connection is + * initiated. + * + * It creates a unique token to identify the new mptcp connection, + * a secret local key and the initial data sequence number (idsn). + * + * On success, the mptcp connection can be found again using + * the computed token at a later time, this is needed to process + * join requests. + * + * returns 0 on success. + */ +int mptcp_token_new_connect(struct sock *ssk) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + struct mptcp_sock *msk = mptcp_sk(subflow->conn); + int retries = MPTCP_TOKEN_MAX_RETRIES; + struct sock *sk = subflow->conn; + struct token_bucket *bucket; + +again: + mptcp_crypto_key_gen_sha(&subflow->local_key, &subflow->token, + &subflow->idsn); + + 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; + } + + pr_debug("ssk=%p, local_key=%llu, token=%u, idsn=%llu\n", + ssk, subflow->local_key, subflow->token, subflow->idsn); + + 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); + sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); + return 0; +} + +/** + * 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. + */ +void mptcp_token_accept(struct mptcp_subflow_request_sock *req, + struct mptcp_sock *msk) +{ + struct mptcp_subflow_request_sock *pos; + struct sock *sk = (struct sock *)msk; + struct token_bucket *bucket; + + sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); + bucket = token_bucket(req->token); + spin_lock_bh(&bucket->lock); + + /* 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); +} + +bool mptcp_token_exists(u32 token) +{ + struct hlist_nulls_node *pos; + struct token_bucket *bucket; + struct mptcp_sock *msk; + struct sock *sk; + + 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) + goto found; + } + if (get_nulls_value(pos) != (token & token_mask)) + goto again; + + rcu_read_unlock(); + return false; +found: + rcu_read_unlock(); + return true; +} + +/** + * mptcp_token_get_sock - retrieve mptcp connection sock using its token + * @net: restrict to this namespace + * @token: token of the mptcp connection to retrieve + * + * This function returns the mptcp connection structure with the given token. + * A reference count on the mptcp socket returned is taken. + * + * returns NULL if no connection with the given token value exists. + */ +struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token) +{ + struct hlist_nulls_node *pos; + struct token_bucket *bucket; + struct mptcp_sock *msk; + struct sock *sk; + + 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 || + !net_eq(sock_net(sk), net)) + continue; + + if (!refcount_inc_not_zero(&sk->sk_refcnt)) + goto not_found; + + if (READ_ONCE(msk->token) != token || + !net_eq(sock_net(sk), net)) { + sock_put(sk); + goto again; + } + goto found; + } + if (get_nulls_value(pos) != (token & token_mask)) + goto again; + +not_found: + msk = NULL; + +found: + rcu_read_unlock(); + return msk; +} +EXPORT_SYMBOL_GPL(mptcp_token_get_sock); + +/** + * mptcp_token_iter_next - iterate over the token container from given pos + * @net: namespace to be iterated + * @s_slot: start slot number + * @s_num: start number inside the given lock + * + * This function returns the first mptcp connection structure found inside the + * token container starting from the specified position, or NULL. + * + * On successful iteration, the iterator is moved to the next position and + * a reference to the returned socket is acquired. + */ +struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot, + long *s_num) +{ + struct mptcp_sock *ret = NULL; + struct hlist_nulls_node *pos; + int slot, num = 0; + + for (slot = *s_slot; slot <= token_mask; *s_num = 0, slot++) { + struct token_bucket *bucket = &token_hash[slot]; + struct sock *sk; + + num = 0; + + if (hlist_nulls_empty(&bucket->msk_chain)) + continue; + + rcu_read_lock(); + sk_nulls_for_each_rcu(sk, pos, &bucket->msk_chain) { + ++num; + if (!net_eq(sock_net(sk), net)) + continue; + + if (num <= *s_num) + continue; + + if (!refcount_inc_not_zero(&sk->sk_refcnt)) + continue; + + if (!net_eq(sock_net(sk), net)) { + sock_put(sk); + continue; + } + + ret = mptcp_sk(sk); + rcu_read_unlock(); + goto out; + } + rcu_read_unlock(); + } + +out: + *s_slot = slot; + *s_num = num; + return ret; +} +EXPORT_SYMBOL_GPL(mptcp_token_iter_next); + +/** + * mptcp_token_destroy_request - remove mptcp connection/token + * @req: mptcp request socket dropping the token + * + * Remove the token associated to @req. + */ +void mptcp_token_destroy_request(struct request_sock *req) +{ + 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 + * @msk: mptcp connection dropping the token + * + * Remove the token associated to @msk + */ +void mptcp_token_destroy(struct mptcp_sock *msk) +{ + struct sock *sk = (struct sock *)msk; + struct token_bucket *bucket; + struct mptcp_sock *pos; + + if (sk_unhashed((struct sock *)msk)) + return; + + sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); + 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); + WRITE_ONCE(msk->token, 0); +} + +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 */ + HASH_ZERO, + 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); + } +} + +#if IS_MODULE(CONFIG_MPTCP_KUNIT_TEST) +EXPORT_SYMBOL_GPL(mptcp_token_new_request); +EXPORT_SYMBOL_GPL(mptcp_token_new_connect); +EXPORT_SYMBOL_GPL(mptcp_token_accept); +EXPORT_SYMBOL_GPL(mptcp_token_destroy_request); +EXPORT_SYMBOL_GPL(mptcp_token_destroy); +#endif -- cgit v1.2.3