From 79c0949e9a09f6a14a6dd18dc8396029423f9b68 Mon Sep 17 00:00:00 2001 From: Peter Krystad Date: Tue, 21 Jan 2020 16:56:20 -0800 Subject: mptcp: Add key generation and token tree Generate the local keys, IDSN, and token when creating a new socket. Introduce the token tree to track all tokens in use using a radix tree with the MPTCP token itself as the index. Override the rebuild_header callback in inet_connection_sock_af_ops for creating the local key on a new outgoing connection. Override the init_req callback of tcp_request_sock_ops for creating the local key on a new incoming connection. Will be used to obtain the MPTCP parent socket to handle incoming joins. Co-developed-by: Davide Caratti Signed-off-by: Davide Caratti Co-developed-by: Florian Westphal Signed-off-by: Florian Westphal Co-developed-by: Paolo Abeni Signed-off-by: Paolo Abeni Signed-off-by: Peter Krystad Signed-off-by: Christoph Paasch Signed-off-by: David S. Miller --- net/mptcp/token.c | 195 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 195 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 000000000000..84d887806090 --- /dev/null +++ b/net/mptcp/token.c @@ -0,0 +1,195 @@ +// 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" + +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; + +/** + * 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); + int err; + + while (1) { + u32 token; + + 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); + } + + err = radix_tree_insert(&token_req_tree, + subflow_req->token, &token_used); + spin_unlock_bh(&token_tree_lock); + return err; +} + +/** + * mptcp_token_new_connect - create new key/idsn/token for subflow + * @sk - 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 *sk) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); + struct sock *mptcp_sock = subflow->conn; + int err; + + while (1) { + u32 token; + + 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); + } + err = radix_tree_insert(&token_tree, subflow->token, mptcp_sock); + spin_unlock_bh(&token_tree_lock); + + return err; +} + +/** + * mptcp_token_new_accept - insert token for later processing + * @token: the token to insert to the tree + * + * Called when a SYN packet creates a new logical connection, i.e. + * is not a join request. + * + * We don't have an mptcp socket yet at that point. + * This is paired with mptcp_token_update_accept, called on accept(). + */ +int mptcp_token_new_accept(u32 token) +{ + int err; + + spin_lock_bh(&token_tree_lock); + err = radix_tree_insert(&token_tree, token, &token_used); + spin_unlock_bh(&token_tree_lock); + + return err; +} + +/** + * mptcp_token_update_accept - update token to map to mptcp socket + * @conn: the new struct mptcp_sock + * @sk: the initial subflow for this mptcp socket + * + * Called when the first mptcp socket is created on accept to + * refresh the dummy mapping (done to reserve the token) with + * the mptcp_socket structure that wasn't allocated before. + */ +void mptcp_token_update_accept(struct sock *sk, struct sock *conn) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); + void __rcu **slot; + + spin_lock_bh(&token_tree_lock); + slot = radix_tree_lookup_slot(&token_tree, subflow->token); + WARN_ON_ONCE(!slot); + if (slot) { + WARN_ON_ONCE(rcu_access_pointer(*slot) != &token_used); + radix_tree_replace_slot(&token_tree, slot, conn); + } + spin_unlock_bh(&token_tree_lock); +} + +/** + * mptcp_token_destroy_request - remove mptcp connection/token + * @token - token of mptcp connection to remove + * + * Remove not-yet-fully-established incoming connection identified + * by @token. + */ +void mptcp_token_destroy_request(u32 token) +{ + spin_lock_bh(&token_tree_lock); + radix_tree_delete(&token_req_tree, token); + spin_unlock_bh(&token_tree_lock); +} + +/** + * mptcp_token_destroy - remove mptcp connection/token + * @token - token of mptcp connection to remove + * + * Remove the connection identified by @token. + */ +void mptcp_token_destroy(u32 token) +{ + spin_lock_bh(&token_tree_lock); + radix_tree_delete(&token_tree, token); + spin_unlock_bh(&token_tree_lock); +} -- cgit v1.2.3