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Miller" Cc: linux-kernel@vger.kernel.org, Dmitry Safonov , Andy Lutomirski , Ard Biesheuvel , Bob Gilligan , Dan Carpenter , David Laight , Dmitry Safonov <0x7f454c46@gmail.com>, Donald Cassidy , Eric Biggers , "Eric W. Biederman" , Francesco Ruggeri , Herbert Xu , Hideaki YOSHIFUJI , Ivan Delalande , Leonard Crestez , Salam Noureddine , netdev@vger.kernel.org Subject: [PATCH v7 20/22] net/tcp: Add static_key for TCP-AO Date: Thu, 15 Jun 2023 00:09:45 +0100 Message-Id: <20230614230947.3954084-21-dima@arista.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230614230947.3954084-1-dima@arista.com> References: <20230614230947.3954084-1-dima@arista.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org Similarly to TCP-MD5, add a static key to TCP-AO that is patched out when there are no keys on a machine and dynamically enabled with the first setsockopt(TCP_AO) adds a key on any socket. The static key is as well dynamically disabled later when the socket is destructed. The lifetime of enabled static key here is the same as ao_info: it is enabled on allocation, passed over from full socket to twsk and destructed when ao_info is scheduled for destruction. Signed-off-by: Dmitry Safonov --- include/net/tcp.h | 3 +++ include/net/tcp_ao.h | 2 ++ net/ipv4/tcp_ao.c | 23 +++++++++++++++++++++++ net/ipv4/tcp_input.c | 42 ++++++++++++++++++++++++++++-------------- 4 files changed, 56 insertions(+), 14 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 1d3cf13ae66b..6060513ab83d 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2585,6 +2585,9 @@ static inline bool tcp_ao_required(struct sock *sk, const void *saddr, struct tcp_ao_info *ao_info; struct tcp_ao_key *ao_key; + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return false; + ao_info = rcu_dereference_check(tcp_sk(sk)->ao_info, lockdep_sock_is_held(sk)); if (!ao_info) diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index 49402458b69d..714a46e30f3f 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -138,6 +138,8 @@ do { \ #ifdef CONFIG_TCP_AO /* TCP-AO structures and functions */ +#include +extern struct static_key_false_deferred tcp_ao_needed; struct tcp4_ao_context { __be32 saddr; diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 3799432a386a..2c4a31d8f177 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -17,6 +17,9 @@ #include #include +DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ); +EXPORT_SYMBOL_GPL(tcp_ao_needed); + int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx, unsigned int len) { @@ -58,6 +61,9 @@ bool tcp_ao_ignore_icmp(struct sock *sk, int type, int code) struct tcp_ao_info *ao; bool ignore_icmp = false; + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return false; + /* RFC5925, 7.8: * >> A TCP-AO implementation MUST default to ignore incoming ICMPv4 * messages of Type 3 (destination unreachable), Codes 2-4 (protocol @@ -198,6 +204,9 @@ static struct tcp_ao_key *__tcp_ao_do_lookup(const struct sock *sk, struct tcp_ao_key *key; struct tcp_ao_info *ao; + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return NULL; + ao = rcu_dereference_check(tcp_sk(sk)->ao_info, lockdep_sock_is_held(sk)); if (!ao) @@ -292,6 +301,7 @@ void tcp_ao_destroy_sock(struct sock *sk, bool twsk) } kfree_rcu(ao, rcu); + static_branch_slow_dec_deferred(&tcp_ao_needed); } void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp) @@ -1107,6 +1117,11 @@ int tcp_ao_copy_all_matching(const struct sock *sk, struct sock *newsk, goto free_and_exit; } + if (!static_key_fast_inc_not_disabled(&tcp_ao_needed.key.key)) { + ret = -EUSERS; + goto free_and_exit; + } + key_head = rcu_dereference(hlist_first_rcu(&new_ao->head)); first_key = hlist_entry_safe(key_head, struct tcp_ao_key, node); @@ -1523,6 +1538,10 @@ static int tcp_ao_add_cmd(struct sock *sk, unsigned short int family, tcp_ao_link_mkt(ao_info, key); if (first) { + if (!static_branch_inc(&tcp_ao_needed.key)) { + ret = -EUSERS; + goto err_free_sock; + } sk_gso_disable(sk); rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info); } @@ -1788,6 +1807,10 @@ static int tcp_ao_info_cmd(struct sock *sk, unsigned short int family, if (new_rnext) WRITE_ONCE(ao_info->rnext_key, new_rnext); if (first) { + if (!static_branch_inc(&tcp_ao_needed.key)) { + err = -EUSERS; + goto out; + } sk_gso_disable(sk); rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info); } diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index eed3f7631b4b..c0c18b05fd1c 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3524,17 +3524,14 @@ static inline bool tcp_may_update_window(const struct tcp_sock *tp, (ack_seq == tp->snd_wl1 && nwin > tp->snd_wnd); } -/* If we update tp->snd_una, also update tp->bytes_acked */ -static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack) +static void tcp_snd_sne_update(struct tcp_sock *tp, u32 ack) { - u32 delta = ack - tp->snd_una; #ifdef CONFIG_TCP_AO struct tcp_ao_info *ao; -#endif - sock_owned_by_me((struct sock *)tp); - tp->bytes_acked += delta; -#ifdef CONFIG_TCP_AO + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return; + ao = rcu_dereference_protected(tp->ao_info, lockdep_sock_is_held((struct sock *)tp)); if (ao) { @@ -3543,20 +3540,27 @@ static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack) ao->snd_sne_seq = ack; } #endif +} + +/* If we update tp->snd_una, also update tp->bytes_acked */ +static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack) +{ + u32 delta = ack - tp->snd_una; + + sock_owned_by_me((struct sock *)tp); + tp->bytes_acked += delta; + tcp_snd_sne_update(tp, ack); tp->snd_una = ack; } -/* If we update tp->rcv_nxt, also update tp->bytes_received */ -static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq) +static void tcp_rcv_sne_update(struct tcp_sock *tp, u32 seq) { - u32 delta = seq - tp->rcv_nxt; #ifdef CONFIG_TCP_AO struct tcp_ao_info *ao; -#endif - sock_owned_by_me((struct sock *)tp); - tp->bytes_received += delta; -#ifdef CONFIG_TCP_AO + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return; + ao = rcu_dereference_protected(tp->ao_info, lockdep_sock_is_held((struct sock *)tp)); if (ao) { @@ -3565,6 +3569,16 @@ static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq) ao->rcv_sne_seq = seq; } #endif +} + +/* If we update tp->rcv_nxt, also update tp->bytes_received */ +static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq) +{ + u32 delta = seq - tp->rcv_nxt; + + sock_owned_by_me((struct sock *)tp); + tp->bytes_received += delta; + tcp_rcv_sne_update(tp, seq); WRITE_ONCE(tp->rcv_nxt, seq); }