Messages in this thread Patch in this message | | | From | Dmitry Safonov <> | Subject | [PATCH v4 20/21] net/tcp-ao: Add static_key for TCP-AO | Date | Wed, 15 Feb 2023 18:33:34 +0000 |
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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 <dima@arista.com> --- include/net/tcp_ao.h | 2 ++ net/ipv4/tcp_ao.c | 17 +++++++++++++++++ net/ipv4/tcp_input.c | 42 ++++++++++++++++++++++++++++-------------- 3 files changed, 47 insertions(+), 14 deletions(-)
diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index 04e3bcee05f7..253cf2719aed 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -131,6 +131,8 @@ do { \ #ifdef CONFIG_TCP_AO /* TCP-AO structures and functions */ +#include <linux/jump_label.h> +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 2c38e991ecbd..adb25e42f64a 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -17,6 +17,9 @@ #include <net/ipv6.h> #include <net/icmp.h> +DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ); +EXPORT_SYMBOL(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 @@ -196,6 +202,9 @@ 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) @@ -283,6 +292,7 @@ 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) @@ -1052,6 +1062,11 @@ 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); @@ -1607,6 +1622,8 @@ 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)) + goto err_free_sock; 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 9f23cab1e835..dd9ff507bbc9 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); } -- 2.39.1
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