From patchwork Wed Aug 2 17:26:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Safonov X-Patchwork-Id: 13338606 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA63F1094B for ; Wed, 2 Aug 2023 17:27:50 +0000 (UTC) Received: from mail-wm1-x329.google.com (mail-wm1-x329.google.com [IPv6:2a00:1450:4864:20::329]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6AFBB30ED for ; Wed, 2 Aug 2023 10:27:25 -0700 (PDT) Received: by mail-wm1-x329.google.com with SMTP id 5b1f17b1804b1-3fe1a17f983so983645e9.3 for ; Wed, 02 Aug 2023 10:27:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=google; t=1690997240; x=1691602040; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=pkqrkZZVEVMZ/t33Ejq/LUymDHE6B9LdRNtsfoOJ+88=; b=GrKK/6rVD/pSzuylUWB/8UNV4Y+IWe2Zp4k13lSg/itm2h538TYi5BLv/bVdKt7pmH dwzkM97RmxU4D1wdMZzcp7hNE9bC2y2sDghs112tjGPtyEU4o6QeJe7i2Fp6Irc5EMRQ GdAfW/vdETnsA1a1glmXedMrp9uUVVjJYOyQIM/guZ8xzNI1CiWA+69u5xzHi2zLoTR9 DeMpFEG4X/anNg7OgTIcRtSZ0f6exl2qs60T3NfVtzc1UQhLtceEhI2dbThnKrnpwd/Y +pizYjWM7LdUpk7Ggk5zrZN5WooWorBXIYTS5Ef4VQ1bmKBExJeKayAg8Xocd1POUy44 4AWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690997240; x=1691602040; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=pkqrkZZVEVMZ/t33Ejq/LUymDHE6B9LdRNtsfoOJ+88=; b=byX6rUqRO+QxDIzhFhEpuninvgR58372m/2DkRJa/4u72z66UAUEni0pctGzUzzZf2 0raHwYeHt1KcSI9qePQ1nEa3R1HGESwK8WEBHMPAk1MIbtMZen6J3Tasv3fl8FLGZv7f /NsVqVwCRkfgZMd0NLKGc6WqQ7yF1Bz0TwJQqu+wxJvjnSQvl/HUyOGdIB0uvCjwReQn Hdvvf2BcobTggrlNAewKTFlDq2EGKk7M2eSy9M13LLc/rMTsAYYme53P3xG5V/qh/4JA keE5l8/C0/mK4Wlimlc42jG0IHiLdEw6N31t6ze0O13FfdBudSzO/hYpVY5HOUnUOCF3 fLlg== X-Gm-Message-State: ABy/qLbj0xNUIVLeR30XKCLlSWtcwqMBOPaN5UoQ3mlr+mqSq0XkDPfl JduHegI/v5wPMfcu9d7Lbxt9Mg== X-Google-Smtp-Source: APBJJlENuwlgNNp2vQjIRLSY8VXV70Z5AM8SdE0NlbR2q9GCo1SsikNHo4nd5zRWof4s9QJHRJuVBA== X-Received: by 2002:a7b:ce0f:0:b0:3fe:22a9:907 with SMTP id m15-20020a7bce0f000000b003fe22a90907mr5474697wmc.20.1690997239571; Wed, 02 Aug 2023 10:27:19 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id q5-20020a1ce905000000b003fbc0a49b57sm2221770wmc.6.2023.08.02.10.27.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Aug 2023 10:27:19 -0700 (PDT) From: Dmitry Safonov To: David Ahern , Eric Dumazet , Paolo Abeni , Jakub Kicinski , "David S. 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 , "Gaillardetz, Dominik" , Herbert Xu , Hideaki YOSHIFUJI , Ivan Delalande , Leonard Crestez , Salam Noureddine , "Tetreault, Francois" , netdev@vger.kernel.org Subject: [PATCH v9 net-next 09/23] net/tcp: Add TCP-AO sign to twsk Date: Wed, 2 Aug 2023 18:26:36 +0100 Message-ID: <20230802172654.1467777-10-dima@arista.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230802172654.1467777-1-dima@arista.com> References: <20230802172654.1467777-1-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_BLOCKED,SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE, URIBL_BLOCKED autolearn=unavailable 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 Add support for sockets in time-wait state. ao_info as well as all keys are inherited on transition to time-wait socket. The lifetime of ao_info is now protected by ref counter, so that tcp_ao_destroy_sock() will destruct it only when the last user is gone. Co-developed-by: Francesco Ruggeri Signed-off-by: Francesco Ruggeri Co-developed-by: Salam Noureddine Signed-off-by: Salam Noureddine Signed-off-by: Dmitry Safonov Acked-by: David Ahern --- include/linux/tcp.h | 3 ++ include/net/tcp_ao.h | 13 +++++++-- net/ipv4/tcp_ao.c | 48 +++++++++++++++++++++++++------ net/ipv4/tcp_ipv4.c | 61 ++++++++++++++++++++++++++++++++++++---- net/ipv4/tcp_minisocks.c | 4 ++- net/ipv4/tcp_output.c | 2 +- net/ipv6/tcp_ipv6.c | 41 ++++++++++++++++++++++++--- 7 files changed, 149 insertions(+), 23 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 9eb15e798c32..0cfa8dbf9159 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -502,6 +502,9 @@ struct tcp_timewait_sock { #ifdef CONFIG_TCP_MD5SIG struct tcp_md5sig_key *tw_md5_key; #endif +#ifdef CONFIG_TCP_AO + struct tcp_ao_info __rcu *ao_info; +#endif }; static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index 67f997aabd9c..ab9163bae48d 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -85,6 +85,7 @@ struct tcp_ao_info { __unused :31; __be32 lisn; __be32 risn; + atomic_t refcnt; /* Protects twsk destruction */ struct rcu_head rcu; }; @@ -121,7 +122,8 @@ struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao, int sndid, int rcvid); int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx, unsigned int len, struct tcp_sigpool *hp); -void tcp_ao_destroy_sock(struct sock *sk); +void tcp_ao_destroy_sock(struct sock *sk, bool twsk); +void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp); struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, const union tcp_ao_addr *addr, int family, int sndid, int rcvid); @@ -131,7 +133,7 @@ int tcp_ao_hash_hdr(unsigned short family, char *ao_hash, const union tcp_ao_addr *saddr, const struct tcphdr *th, u32 sne); int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, - const struct tcp_ao_hdr *aoh, int l3index, u32 seq, + const struct tcp_ao_hdr *aoh, int l3index, __be32 seq, struct tcp_ao_key **key, char **traffic_key, bool *allocated_traffic_key, u8 *keyid, u32 *sne); @@ -171,7 +173,7 @@ static inline struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, return NULL; } -static inline void tcp_ao_destroy_sock(struct sock *sk) +static inline void tcp_ao_destroy_sock(struct sock *sk, bool twsk) { } @@ -179,6 +181,11 @@ static inline void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb) { } +static inline void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, + struct tcp_sock *tp) +{ +} + static inline void tcp_ao_connect_init(struct sock *sk) { } diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 81ce4fe546f2..93072a5ada5c 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -159,6 +159,7 @@ static struct tcp_ao_info *tcp_ao_alloc_info(gfp_t flags) if (!ao) return NULL; INIT_HLIST_HEAD(&ao->head); + atomic_set(&ao->refcnt, 1); return ao; } @@ -176,27 +177,54 @@ static void tcp_ao_key_free_rcu(struct rcu_head *head) kfree(key); } -void tcp_ao_destroy_sock(struct sock *sk) +void tcp_ao_destroy_sock(struct sock *sk, bool twsk) { struct tcp_ao_info *ao; struct tcp_ao_key *key; struct hlist_node *n; - ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1); - tcp_sk(sk)->ao_info = NULL; + if (twsk) { + ao = rcu_dereference_protected(tcp_twsk(sk)->ao_info, 1); + tcp_twsk(sk)->ao_info = NULL; + } else { + ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1); + tcp_sk(sk)->ao_info = NULL; + } - if (!ao) + if (!ao || !atomic_dec_and_test(&ao->refcnt)) return; hlist_for_each_entry_safe(key, n, &ao->head, node) { hlist_del_rcu(&key->node); - atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); + if (!twsk) + atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); call_rcu(&key->rcu, tcp_ao_key_free_rcu); } kfree_rcu(ao, rcu); } +void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp) +{ + struct tcp_ao_info *ao_info = rcu_dereference_protected(tp->ao_info, 1); + + if (ao_info) { + struct tcp_ao_key *key; + struct hlist_node *n; + int omem = 0; + + hlist_for_each_entry_safe(key, n, &ao_info->head, node) { + omem += tcp_ao_sizeof_key(key); + } + + atomic_inc(&ao_info->refcnt); + atomic_sub(omem, &(((struct sock *)tp)->sk_omem_alloc)); + rcu_assign_pointer(tcptw->ao_info, ao_info); + } else { + tcptw->ao_info = NULL; + } +} + /* 4 tuple and ISNs are expected in NBO */ static int tcp_v4_ao_calc_key(struct tcp_ao_key *mkt, u8 *key, __be32 saddr, __be32 daddr, @@ -496,7 +524,7 @@ struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, } int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, - const struct tcp_ao_hdr *aoh, int l3index, u32 seq, + const struct tcp_ao_hdr *aoh, int l3index, __be32 seq, struct tcp_ao_key **key, char **traffic_key, bool *allocated_traffic_key, u8 *keyid, u32 *sne) { @@ -519,8 +547,9 @@ int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, struct tcp_ao_key *rnext_key; if (sk->sk_state == TCP_TIME_WAIT) - return -1; - ao_info = rcu_dereference(tcp_sk(sk)->ao_info); + ao_info = rcu_dereference(tcp_twsk(sk)->ao_info); + else + ao_info = rcu_dereference(tcp_sk(sk)->ao_info); if (!ao_info) return -ENOENT; @@ -862,6 +891,9 @@ static struct tcp_ao_info *setsockopt_ao_info(struct sock *sk) if (sk_fullsock(sk)) { return rcu_dereference_protected(tcp_sk(sk)->ao_info, lockdep_sock_is_held(sk)); + } else if (sk->sk_state == TCP_TIME_WAIT) { + return rcu_dereference_protected(tcp_twsk(sk)->ao_info, + lockdep_sock_is_held(sk)); } return ERR_PTR(-ESOCKTNOSUPPORT); } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 14e1024141a0..a9f69107b9be 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -912,16 +912,16 @@ static void tcp_v4_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 tsval, u32 tsecr, int oif, struct tcp_md5sig_key *key, + struct tcp_ao_key *ao_key, + u8 *traffic_key, + u8 rcv_next, + u32 ao_sne, int reply_flags, u8 tos, u32 txhash) { const struct tcphdr *th = tcp_hdr(skb); struct { struct tcphdr th; - __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2) -#ifdef CONFIG_TCP_MD5SIG - + (TCPOLEN_MD5SIG_ALIGNED >> 2) -#endif - ]; + __be32 opt[(MAX_TCP_OPTION_SPACE >> 2)]; } rep; struct net *net = sock_net(sk); struct ip_reply_arg arg; @@ -966,6 +966,24 @@ static void tcp_v4_send_ack(const struct sock *sk, key, ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, &rep.th); } +#endif +#ifdef CONFIG_TCP_AO + if (ao_key) { + int offset = (tsecr) ? 3 : 0; + + rep.opt[offset++] = htonl((TCPOPT_AO << 24) | + (tcp_ao_len(ao_key) << 16) | + (ao_key->sndid << 8) | rcv_next); + arg.iov[0].iov_len += round_up(tcp_ao_len(ao_key), 4); + rep.th.doff = arg.iov[0].iov_len / 4; + + tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset], + ao_key, traffic_key, + (union tcp_ao_addr *)&ip_hdr(skb)->saddr, + (union tcp_ao_addr *)&ip_hdr(skb)->daddr, + &rep.th, ao_sne); + } + WARN_ON_ONCE(key && ao_key); #endif arg.flags = reply_flags; arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, @@ -999,6 +1017,32 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) { struct inet_timewait_sock *tw = inet_twsk(sk); struct tcp_timewait_sock *tcptw = tcp_twsk(sk); + struct tcp_ao_key *ao_key = NULL; + u8 *traffic_key = NULL; + u8 rcv_next = 0; + u32 ao_sne = 0; +#ifdef CONFIG_TCP_AO + struct tcp_ao_info *ao_info; + + /* FIXME: the segment to-be-acked is not verified yet */ + ao_info = rcu_dereference(tcptw->ao_info); + if (ao_info) { + const struct tcp_ao_hdr *aoh; + + if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) + goto out; /* something is wrong with the sign */ + + if (aoh) + ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1); + } + if (ao_key) { + struct tcp_ao_key *rnext_key; + + traffic_key = snd_other_key(ao_key); + rnext_key = READ_ONCE(ao_info->rnext_key); + rcv_next = rnext_key->rcvid; + } +#endif tcp_v4_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, @@ -1007,11 +1051,15 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw), + ao_key, traffic_key, rcv_next, ao_sne, tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0, tw->tw_tos, tw->tw_txhash ); +#ifdef CONFIG_TCP_AO +out: +#endif inet_twsk_put(tw); } @@ -1041,6 +1089,7 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, READ_ONCE(req->ts_recent), 0, tcp_md5_do_lookup(sk, l3index, addr, AF_INET), + NULL, NULL, 0, 0, inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, ip_hdr(skb)->tos, READ_ONCE(tcp_rsk(req)->txhash)); @@ -2402,7 +2451,7 @@ void tcp_v4_destroy_sock(struct sock *sk) rcu_assign_pointer(tp->md5sig_info, NULL); } #endif - tcp_ao_destroy_sock(sk); + tcp_ao_destroy_sock(sk, false); /* Clean up a referenced TCP bind bucket. */ if (inet_csk(sk)->icsk_bind_hash) diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 5616b6a34bee..3033f3187079 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -279,7 +279,7 @@ static void tcp_time_wait_init(struct sock *sk, struct tcp_timewait_sock *tcptw) void tcp_time_wait(struct sock *sk, int state, int timeo) { const struct inet_connection_sock *icsk = inet_csk(sk); - const struct tcp_sock *tp = tcp_sk(sk); + struct tcp_sock *tp = tcp_sk(sk); struct net *net = sock_net(sk); struct inet_timewait_sock *tw; @@ -316,6 +316,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo) #endif tcp_time_wait_init(sk, tcptw); + tcp_ao_time_wait(tcptw, tp); /* Get the TIME_WAIT timeout firing. */ if (timeo < rto) @@ -370,6 +371,7 @@ void tcp_twsk_destructor(struct sock *sk) call_rcu(&twsk->tw_md5_key->rcu, tcp_md5_twsk_free_rcu); } #endif + tcp_ao_destroy_sock(sk, true); } EXPORT_SYMBOL_GPL(tcp_twsk_destructor); diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index a234c43727b2..f2d7671af811 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -4050,7 +4050,7 @@ int tcp_connect(struct sock *sk) * then free up ao_info if allocated. */ if (needs_md5) { - tcp_ao_destroy_sock(sk); + tcp_ao_destroy_sock(sk, false); } else if (needs_ao) { tcp_clear_md5_list(sk); kfree(rcu_replace_pointer(tp->md5sig_info, NULL, diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 6f7651f26b03..9cb3fc40e682 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1137,24 +1137,57 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 tsval, u32 tsecr, int oif, struct tcp_md5sig_key *key, u8 tclass, - __be32 label, u32 priority, u32 txhash) + __be32 label, u32 priority, u32 txhash, + struct tcp_ao_key *ao_key, char *tkey, + u8 rcv_next, u32 ao_sne) { tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0, - tclass, label, priority, txhash, NULL, NULL, 0, 0); + tclass, label, priority, txhash, + ao_key, tkey, rcv_next, ao_sne); } static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) { struct inet_timewait_sock *tw = inet_twsk(sk); struct tcp_timewait_sock *tcptw = tcp_twsk(sk); + struct tcp_ao_key *ao_key = NULL; + u8 *traffic_key = NULL; + u8 rcv_next = 0; + u32 ao_sne = 0; +#ifdef CONFIG_TCP_AO + struct tcp_ao_info *ao_info; + + /* FIXME: the segment to-be-acked is not verified yet */ + ao_info = rcu_dereference(tcptw->ao_info); + if (ao_info) { + const struct tcp_ao_hdr *aoh; + + /* Invalid TCP option size or twice included auth */ + if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) + goto out; + if (aoh) + ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1); + } + if (ao_key) { + struct tcp_ao_key *rnext_key; + + traffic_key = snd_other_key(ao_key); + /* rcv_next switches to our rcv_next */ + rnext_key = READ_ONCE(ao_info->rnext_key); + rcv_next = rnext_key->rcvid; + } +#endif tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, tcp_time_stamp_raw() + tcptw->tw_ts_offset, tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw), tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority, - tw->tw_txhash); + tw->tw_txhash, ao_key, traffic_key, rcv_next, ao_sne); +#ifdef CONFIG_TCP_AO +out: +#endif inet_twsk_put(tw); } @@ -1181,7 +1214,7 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, READ_ONCE(req->ts_recent), sk->sk_bound_dev_if, tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr, l3index), ipv6_get_dsfield(ipv6_hdr(skb)), 0, sk->sk_priority, - READ_ONCE(tcp_rsk(req)->txhash)); + READ_ONCE(tcp_rsk(req)->txhash), NULL, NULL, 0, 0); }