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path: root/include/net/tcp.h
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2026-03-12tcp: secure_seq: add back ports to TS offsetEric Dumazet
[ Upstream commit 165573e41f2f66ef98940cf65f838b2cb575d9d1 ] This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset. Fixes: 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") Reported-by: Zhouyan Deng <dengzhouyan_nwpu@163.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Acked-by: Florian Westphal <fw@strlen.de> Link: https://patch.msgid.link/20260302205527.1982836-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04tcp: fix potential race in tcp_v6_syn_recv_sock()Eric Dumazet
[ Upstream commit 858d2a4f67ff69e645a43487ef7ea7f28f06deae ] Code in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock() is done too late. After tcp_v4_syn_recv_sock(), the child socket is already visible from TCP ehash table and other cpus might use it. Since newinet->pinet6 is still pointing to the listener ipv6_pinfo bad things can happen as syzbot found. Move the problematic code in tcp_v6_mapped_child_init() and call this new helper from tcp_v4_syn_recv_sock() before the ehash insertion. This allows the removal of one tcp_sync_mss(), since tcp_v4_syn_recv_sock() will call it with the correct context. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+937b5bbb6a815b3e5d0b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/69949275.050a0220.2eeac1.0145.GAE@google.com/ Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20260217161205.2079883-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-26tcp: disable RFC3168 fallback identifier for CC modulesChia-Yu Chang
[ Upstream commit e68c28f22f46ecfdec3656ae785dd8ccbb4d557d ] When AccECN is not successfully negociated for a TCP flow, it defaults fallback to classic ECN (RFC3168). However, L4S service will fallback to non-ECN. This patch enables congestion control module to control whether it should not fallback to classic ECN after unsuccessful AccECN negotiation. A new CA module flag (TCP_CONG_NO_FALLBACK_RFC3168) identifies this behavior expected by the CA. Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260131222515.8485-6-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Stable-dep-of: c5ff6b837159 ("tcp: accecn: handle unexpected AccECN negotiation feedback") Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-26tcp: ECT_1_NEGOTIATION and NEEDS_ACCECN identifiersChia-Yu Chang
[ Upstream commit 100f946b8d44b64bc0b8a8c30d283105031c0a77 ] Two flags for congestion control (CC) module are added in this patch related to AccECN negotiation. First, a new flag (TCP_CONG_NEEDS_ACCECN) defines that the CC expects to negotiate AccECN functionality using the ECE, CWR and AE flags in the TCP header. Second, during ECN negotiation, ECT(0) in the IP header is used. This patch enables CC to control whether ECT(0) or ECT(1) should be used on a per-segment basis. A new flag (TCP_CONG_ECT_1_NEGOTIATION) defines the expected ECT value in the IP header by the CA when not-yet initialized for the connection. The detailed AccECN negotiaotn can be found in IETF RFC9768. Co-developed-by: Olivier Tilmans <olivier.tilmans@nokia.com> Signed-off-by: Olivier Tilmans <olivier.tilmans@nokia.com> Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260131222515.8485-5-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Stable-dep-of: c5ff6b837159 ("tcp: accecn: handle unexpected AccECN negotiation feedback") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-10-29tcp: add newval parameter to tcp_rcvbuf_grow()Eric Dumazet
This patch has no functional change, and prepares the following one. tcp_rcvbuf_grow() will need to have access to tp->rcvq_space.space old and new values. Change mptcp_rcvbuf_grow() in a similar way. Signed-off-by: Eric Dumazet <edumazet@google.com> [ Moved 'oldval' declaration to the next patch to avoid warnings at build time. ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Neal Cardwell <ncardwell@google.com> Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-3-74b43ba4c84c@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-29tcp: make tcp_rcvbuf_grow() accessible to mptcp codePaolo Abeni
To leverage the auto-tuning improvements brought by commit 2da35e4b4df9 ("Merge branch 'tcp-receive-side-improvements'"), the MPTCP stack need to access the mentioned helper. Acked-by: Geliang Tang <geliang@kernel.org> Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250927-net-next-mptcp-rcv-path-imp-v1-2-5da266aa9c1a@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-18tcp: accecn: AccECN option ceb/cep and ACE field multi-wrap heuristicsIlpo Järvinen
The AccECN option ceb/cep heuristic algorithm is from AccECN spec Appendix A.2.2 to mitigate against false ACE field overflows. Armed with ceb delta from option, delivered bytes, and delivered packets it is possible to estimate how many times ACE field wrapped. This calculation is necessary only if more than one wrap is possible. Without SACK, delivered bytes and packets are not always trustworthy in which case TCP falls back to the simpler no-or-all wraps ceb algorithm. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-10-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18tcp: accecn: AccECN option send controlChia-Yu Chang
Instead of sending the option in every ACK, limit sending to those ACKs where the option is necessary: - Handshake - "Change-triggered ACK" + the ACK following it. The 2nd ACK is necessary to unambiguously indicate which of the ECN byte counters in increasing. The first ACK has two counters increasing due to the ecnfield edge. - ACKs with CE to allow CEP delta validations to take advantage of the option. - Force option to be sent every at least once per 2^22 bytes. The check is done using the bit edges of the byte counters (avoids need for extra variables). - AccECN option beacon to send a few times per RTT even if nothing in the ECN state requires that. The default is 3 times per RTT, and its period can be set via sysctl_tcp_ecn_option_beacon. Below are the pahole outcomes before and after this patch, in which the group size of tcp_sock_write_tx is increased from 89 to 97 due to the new u64 accecn_opt_tstamp member: [BEFORE THIS PATCH] struct tcp_sock { [...] u64 tcp_wstamp_ns; /* 2488 8 */ struct list_head tsorted_sent_queue; /* 2496 16 */ [...] __cacheline_group_end__tcp_sock_write_tx[0]; /* 2521 0 */ __cacheline_group_begin__tcp_sock_write_txrx[0]; /* 2521 0 */ u8 nonagle:4; /* 2521: 0 1 */ u8 rate_app_limited:1; /* 2521: 4 1 */ /* XXX 3 bits hole, try to pack */ /* Force alignment to the next boundary: */ u8 :0; u8 received_ce_pending:4;/* 2522: 0 1 */ u8 unused2:4; /* 2522: 4 1 */ u8 accecn_minlen:2; /* 2523: 0 1 */ u8 est_ecnfield:2; /* 2523: 2 1 */ u8 unused3:4; /* 2523: 4 1 */ [...] __cacheline_group_end__tcp_sock_write_txrx[0]; /* 2628 0 */ [...] /* size: 3200, cachelines: 50, members: 171 */ } [AFTER THIS PATCH] struct tcp_sock { [...] u64 tcp_wstamp_ns; /* 2488 8 */ u64 accecn_opt_tstamp; /* 2596 8 */ struct list_head tsorted_sent_queue; /* 2504 16 */ [...] __cacheline_group_end__tcp_sock_write_tx[0]; /* 2529 0 */ __cacheline_group_begin__tcp_sock_write_txrx[0]; /* 2529 0 */ u8 nonagle:4; /* 2529: 0 1 */ u8 rate_app_limited:1; /* 2529: 4 1 */ /* XXX 3 bits hole, try to pack */ /* Force alignment to the next boundary: */ u8 :0; u8 received_ce_pending:4;/* 2530: 0 1 */ u8 unused2:4; /* 2530: 4 1 */ u8 accecn_minlen:2; /* 2531: 0 1 */ u8 est_ecnfield:2; /* 2531: 2 1 */ u8 accecn_opt_demand:2; /* 2531: 4 1 */ u8 prev_ecnfield:2; /* 2531: 6 1 */ [...] __cacheline_group_end__tcp_sock_write_txrx[0]; /* 2636 0 */ [...] /* size: 3200, cachelines: 50, members: 173 */ } Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Co-developed-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Ilpo Järvinen <ij@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-8-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18tcp: accecn: AccECN optionIlpo Järvinen
The Accurate ECN allows echoing back the sum of bytes for each IP ECN field value in the received packets using AccECN option. This change implements AccECN option tx & rx side processing without option send control related features that are added by a later change. Based on specification: https://tools.ietf.org/id/draft-ietf-tcpm-accurate-ecn-28.txt (Some features of the spec will be added in the later changes rather than in this one). A full-length AccECN option is always attempted but if it does not fit, the minimum length is selected based on the counters that have changed since the last update. The AccECN option (with 24-bit fields) often ends in odd sizes so the option write code tries to take advantage of some nop used to pad the other TCP options. The delivered_ecn_bytes pairs with received_ecn_bytes similar to how delivered_ce pairs with received_ce. In contrast to ACE field, however, the option is not always available to update delivered_ecn_bytes. For ACK w/o AccECN option, the delivered bytes calculated based on the cumulative ACK+SACK information are assigned to one of the counters using an estimation heuristic to select the most likely ECN byte counter. Any estimation error is corrected when the next AccECN option arrives. It may occur that the heuristic gets too confused when there are enough different byte counter deltas between ACKs with the AccECN option in which case the heuristic just gives up on updating the counters for a while. tcp_ecn_option sysctl can be used to select option sending mode for AccECN: TCP_ECN_OPTION_DISABLED, TCP_ECN_OPTION_MINIMUM, and TCP_ECN_OPTION_FULL. This patch increases the size of tcp_info struct, as there is no existing holes for new u32 variables. Below are the pahole outcomes before and after this patch: [BEFORE THIS PATCH] struct tcp_info { [...] __u32 tcpi_total_rto_time; /* 244 4 */ /* size: 248, cachelines: 4, members: 61 */ } [AFTER THIS PATCH] struct tcp_info { [...] __u32 tcpi_total_rto_time; /* 244 4 */ __u32 tcpi_received_ce; /* 248 4 */ __u32 tcpi_delivered_e1_bytes; /* 252 4 */ __u32 tcpi_delivered_e0_bytes; /* 256 4 */ __u32 tcpi_delivered_ce_bytes; /* 260 4 */ __u32 tcpi_received_e1_bytes; /* 264 4 */ __u32 tcpi_received_e0_bytes; /* 268 4 */ __u32 tcpi_received_ce_bytes; /* 272 4 */ /* size: 280, cachelines: 5, members: 68 */ } This patch uses the existing 1-byte holes in the tcp_sock_write_txrx group for new u8 members, but adds a 4-byte hole in tcp_sock_write_rx group after the new u32 delivered_ecn_bytes[3] member. Therefore, the group size of tcp_sock_write_rx is increased from 96 to 112. Below are the pahole outcomes before and after this patch: [BEFORE THIS PATCH] struct tcp_sock { [...] u8 received_ce_pending:4; /* 2522: 0 1 */ u8 unused2:4; /* 2522: 4 1 */ /* XXX 1 byte hole, try to pack */ [...] u32 rcv_rtt_last_tsecr; /* 2668 4 */ [...] __cacheline_group_end__tcp_sock_write_rx[0]; /* 2728 0 */ [...] /* size: 3200, cachelines: 50, members: 167 */ } [AFTER THIS PATCH] struct tcp_sock { [...] u8 received_ce_pending:4;/* 2522: 0 1 */ u8 unused2:4; /* 2522: 4 1 */ u8 accecn_minlen:2; /* 2523: 0 1 */ u8 est_ecnfield:2; /* 2523: 2 1 */ u8 unused3:4; /* 2523: 4 1 */ [...] u32 rcv_rtt_last_tsecr; /* 2668 4 */ u32 delivered_ecn_bytes[3];/* 2672 12 */ /* XXX 4 bytes hole, try to pack */ [...] __cacheline_group_end__tcp_sock_write_rx[0]; /* 2744 0 */ [...] /* size: 3200, cachelines: 50, members: 171 */ } Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Neal Cardwell <ncardwell@google.com> Co-developed-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-7-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18tcp: accecn: AccECN negotiationIlpo Järvinen
Accurate ECN negotiation parts based on the specification: https://tools.ietf.org/id/draft-ietf-tcpm-accurate-ecn-28.txt Accurate ECN is negotiated using ECE, CWR and AE flags in the TCP header. TCP falls back into using RFC3168 ECN if one of the ends supports only RFC3168-style ECN. The AccECN negotiation includes reflecting IP ECN field value seen in SYN and SYNACK back using the same bits as negotiation to allow responding to SYN CE marks and to detect ECN field mangling. CE marks should not occur currently because SYN=1 segments are sent with Non-ECT in IP ECN field (but proposal exists to remove this restriction). Reflecting SYN IP ECN field in SYNACK is relatively simple. Reflecting SYNACK IP ECN field in the final/third ACK of the handshake is more challenging. Linux TCP code is not well prepared for using the final/third ACK a signalling channel which makes things somewhat complicated here. tcp_ecn sysctl can be used to select the highest ECN variant (Accurate ECN, ECN, No ECN) that is attemped to be negotiated and requested for incoming connection and outgoing connection: TCP_ECN_IN_NOECN_OUT_NOECN, TCP_ECN_IN_ECN_OUT_ECN, TCP_ECN_IN_ECN_OUT_NOECN, TCP_ECN_IN_ACCECN_OUT_ACCECN, TCP_ECN_IN_ACCECN_OUT_ECN, and TCP_ECN_IN_ACCECN_OUT_NOECN. After this patch, the size of tcp_request_sock remains unchanged and no new holes are added. Below are the pahole outcomes before and after this patch: [BEFORE THIS PATCH] struct tcp_request_sock { [...] u32 rcv_nxt; /* 352 4 */ u8 syn_tos; /* 356 1 */ /* size: 360, cachelines: 6, members: 16 */ } [AFTER THIS PATCH] struct tcp_request_sock { [...] u32 rcv_nxt; /* 352 4 */ u8 syn_tos; /* 356 1 */ bool accecn_ok; /* 357 1 */ u8 syn_ect_snt:2; /* 358: 0 1 */ u8 syn_ect_rcv:2; /* 358: 2 1 */ u8 accecn_fail_mode:4; /* 358: 4 1 */ /* size: 360, cachelines: 6, members: 20 */ } After this patch, the size of tcp_sock remains unchanged and no new holes are added. Also, 4 bits of the existing 2-byte hole are exploited. Below are the pahole outcomes before and after this patch: [BEFORE THIS PATCH] struct tcp_sock { [...] u8 dup_ack_counter:2; /* 2761: 0 1 */ u8 tlp_retrans:1; /* 2761: 2 1 */ u8 unused:5; /* 2761: 3 1 */ u8 thin_lto:1; /* 2762: 0 1 */ u8 fastopen_connect:1; /* 2762: 1 1 */ u8 fastopen_no_cookie:1; /* 2762: 2 1 */ u8 fastopen_client_fail:2; /* 2762: 3 1 */ u8 frto:1; /* 2762: 5 1 */ /* XXX 2 bits hole, try to pack */ [...] u8 keepalive_probes; /* 2765 1 */ /* XXX 2 bytes hole, try to pack */ [...] /* size: 3200, cachelines: 50, members: 164 */ } [AFTER THIS PATCH] struct tcp_sock { [...] u8 dup_ack_counter:2; /* 2761: 0 1 */ u8 tlp_retrans:1; /* 2761: 2 1 */ u8 syn_ect_snt:2; /* 2761: 3 1 */ u8 syn_ect_rcv:2; /* 2761: 5 1 */ u8 thin_lto:1; /* 2761: 7 1 */ u8 fastopen_connect:1; /* 2762: 0 1 */ u8 fastopen_no_cookie:1; /* 2762: 1 1 */ u8 fastopen_client_fail:2; /* 2762: 2 1 */ u8 frto:1; /* 2762: 4 1 */ /* XXX 3 bits hole, try to pack */ [...] u8 keepalive_probes; /* 2765 1 */ u8 accecn_fail_mode:4; /* 2766: 0 1 */ /* XXX 4 bits hole, try to pack */ /* XXX 1 byte hole, try to pack */ [...] /* size: 3200, cachelines: 50, members: 166 */ } Signed-off-by: Ilpo Järvinen <ij@kernel.org> Co-developed-by: Olivier Tilmans <olivier.tilmans@nokia.com> Signed-off-by: Olivier Tilmans <olivier.tilmans@nokia.com> Co-developed-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-3-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-18tcp: AccECN coreIlpo Järvinen
This change implements Accurate ECN without negotiation and AccECN Option (that will be added by later changes). Based on AccECN specifications: https://tools.ietf.org/id/draft-ietf-tcpm-accurate-ecn-28.txt Accurate ECN allows feeding back the number of CE (congestion experienced) marks accurately to the sender in contrast to RFC3168 ECN that can only signal one marks-seen-yes/no per RTT. Congestion control algorithms can take advantage of the accurate ECN information to fine-tune their congestion response to avoid drastic rate reduction when only mild congestion is encountered. With Accurate ECN, tp->received_ce (r.cep in AccECN spec) keeps track of how many segments have arrived with a CE mark. Accurate ECN uses ACE field (ECE, CWR, AE) to communicate the value back to the sender which updates tp->delivered_ce (s.cep) based on the feedback. This signalling channel is lossy when ACE field overflow occurs. Conservative strategy is selected here to deal with the ACE overflow, however, some strategies using the AccECN option later in the overall patchset mitigate against false overflows detected. The ACE field values on the wire are offset by TCP_ACCECN_CEP_INIT_OFFSET. Delivered_ce/received_ce count the real CE marks rather than forcing all downstream users to adapt to the wire offset. This patch uses the first 1-byte hole and the last 4-byte hole of the tcp_sock_write_txrx for 'received_ce_pending' and 'received_ce'. Also, the group size of tcp_sock_write_txrx is increased from 91 + 4 to 95 + 4 due to the new u32 received_ce member. Below are the trimmed pahole outcomes before and after this patch. [BEFORE THIS PATCH] struct tcp_sock { [...] __cacheline_group_begin__tcp_sock_write_txrx[0]; /* 2521 0 */ u8 nonagle:4; /* 2521: 0 1 */ u8 rate_app_limited:1; /* 2521: 4 1 */ /* XXX 3 bits hole, try to pack */ /* XXX 2 bytes hole, try to pack */ [...] u32 delivered_ce; /* 2576 4 */ u32 app_limited; /* 2580 4 */ u32 rcv_wnd; /* 2684 4 */ struct tcp_options_received rx_opt; /* 2688 24 */ __cacheline_group_end__tcp_sock_write_txrx[0]; /* 2612 0 */ /* XXX 4 bytes hole, try to pack */ [...] /* size: 3200, cachelines: 50, members: 161 */ } [AFTER THIS PATCH] struct tcp_sock { [...] __cacheline_group_begin__tcp_sock_write_txrx[0]; /* 2521 0 */ u8 nonagle:4; /* 2521: 0 1 */ u8 rate_app_limited:1; /* 2521: 4 1 */ /* XXX 3 bits hole, try to pack */ /* Force alignment to the next boundary: */ u8 :0; u8 received_ce_pending:4;/* 2522: 0 1 */ u8 unused2:4; /* 2522: 4 1 */ /* XXX 1 byte hole, try to pack */ [...] u32 delivered_ce; /* 2576 4 */ u32 received_ce; /* 2580 4 */ u32 app_limited; /* 2584 4 */ u32 rcv_wnd; /* 2588 4 */ struct tcp_options_received rx_opt; /* 2592 24 */ __cacheline_group_end__tcp_sock_write_txrx[0]; /* 2616 0 */ [...] /* size: 3200, cachelines: 50, members: 164 */ } Signed-off-by: Ilpo Järvinen <ij@kernel.org> Co-developed-by: Olivier Tilmans <olivier.tilmans@nokia.com> Signed-off-by: Olivier Tilmans <olivier.tilmans@nokia.com> Co-developed-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250916082434.100722-2-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-15tcp: fast path functions laterIlpo Järvinen
The following patch will use tcp_ecn_mode_accecn(), TCP_ACCECN_CEP_INIT_OFFSET, TCP_ACCECN_CEP_ACE_MASK in __tcp_fast_path_on() to make new flag for AccECN. No functional changes. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250911110642.87529-3-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-11tcp: Destroy TCP-AO, TCP-MD5 keys in .sk_destruct()Dmitry Safonov
Currently there are a couple of minor issues with destroying the keys tcp_v4_destroy_sock(): 1. The socket is yet in TCP bind buckets, making it reachable for incoming segments [on another CPU core], potentially available to send late FIN/ACK/RST replies. 2. There is at least one code path, where tcp_done() is called before sending RST [kudos to Bob for investigation]. This is a case of a server, that finished sending its data and just called close(). The socket is in TCP_FIN_WAIT2 and has RCV_SHUTDOWN (set by __tcp_close()) tcp_v4_do_rcv()/tcp_v6_do_rcv() tcp_rcv_state_process() /* LINUX_MIB_TCPABORTONDATA */ tcp_reset() tcp_done_with_error() tcp_done() inet_csk_destroy_sock() /* Destroys AO/MD5 keys */ /* tcp_rcv_state_process() returns SKB_DROP_REASON_TCP_ABORT_ON_DATA */ tcp_v4_send_reset() /* Sends an unsigned RST segment */ tcpdump: > 22:53:15.399377 00:00:b2:1f:00:00 > 00:00:01:01:00:00, ethertype IPv4 (0x0800), length 74: (tos 0x0, ttl 64, id 33929, offset 0, flags [DF], proto TCP (6), length 60) > 1.0.0.1.34567 > 1.0.0.2.49848: Flags [F.], seq 2185658590, ack 3969644355, win 502, options [nop,nop,md5 valid], length 0 > 22:53:15.399396 00:00:01:01:00:00 > 00:00:b2:1f:00:00, ethertype IPv4 (0x0800), length 86: (tos 0x0, ttl 64, id 51951, offset 0, flags [DF], proto TCP (6), length 72) > 1.0.0.2.49848 > 1.0.0.1.34567: Flags [.], seq 3969644375, ack 2185658591, win 128, options [nop,nop,md5 valid,nop,nop,sack 1 {2185658590:2185658591}], length 0 > 22:53:16.429588 00:00:b2:1f:00:00 > 00:00:01:01:00:00, ethertype IPv4 (0x0800), length 60: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) > 1.0.0.1.34567 > 1.0.0.2.49848: Flags [R], seq 2185658590, win 0, length 0 > 22:53:16.664725 00:00:b2:1f:00:00 > 00:00:01:01:00:00, ethertype IPv4 (0x0800), length 74: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 60) > 1.0.0.1.34567 > 1.0.0.2.49848: Flags [R], seq 2185658591, win 0, options [nop,nop,md5 valid], length 0 > 22:53:17.289832 00:00:b2:1f:00:00 > 00:00:01:01:00:00, ethertype IPv4 (0x0800), length 74: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 60) > 1.0.0.1.34567 > 1.0.0.2.49848: Flags [R], seq 2185658591, win 0, options [nop,nop,md5 valid], length 0 Note the signed RSTs later in the dump - those are sent by the server when the fin-wait socket gets removed from hash buckets, by the listener socket. Instead of destroying AO/MD5 info and their keys in inet_csk_destroy_sock(), slightly delay it until the actual socket .sk_destruct(). As shutdown'ed socket can yet send non-data replies, they should be signed in order for the peer to process them. Now it also matches how AO/MD5 gets destructed for TIME-WAIT sockets (in tcp_twsk_destructor()). This seems optimal for TCP-MD5, while for TCP-AO it seems to have an open problem: once RST get sent and socket gets actually destructed, there is no information on the initial sequence numbers. So, in case this last RST gets lost in the network, the server's listener socket won't be able to properly sign another RST. Nothing in RFC 1122 prescribes keeping any local state after non-graceful reset. Luckily, BGP are known to use keep alive(s). While the issue is quite minor/cosmetic, these days monitoring network counters is a common practice and getting invalid signed segments from a trusted BGP peer can get customers worried. Investigated-by: Bob Gilligan <gilligan@arista.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Link: https://patch.msgid.link/20250909-b4-tcp-ao-md5-rst-finwait2-v5-1-9ffaaaf8b236@arista.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-01tcp: Remove sk->sk_prot->orphan_count.Kuniyuki Iwashima
TCP tracks the number of orphaned (SOCK_DEAD but not yet destructed) sockets in tcp_orphan_count. In some code that was shared with DCCP, tcp_orphan_count is referenced via sk->sk_prot->orphan_count. Let's reference tcp_orphan_count directly. inet_csk_prepare_for_destroy_sock() is moved to inet_connection_sock.c due to header dependency. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250829215641.711664-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-28net: add sk_drops_read(), sk_drops_inc() and sk_drops_reset() helpersEric Dumazet
We want to split sk->sk_drops in the future to reduce potential contention on this field. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20250826125031.1578842-2-edumazet@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-08-19net-memcg: Pass struct sock to mem_cgroup_sk_under_memory_pressure().Kuniyuki Iwashima
We will store a flag in the lowest bit of sk->sk_memcg. Then, we cannot pass the raw pointer to mem_cgroup_under_socket_pressure(). Let's pass struct sock to it and rename the function to match other functions starting with mem_cgroup_sk_. Note that the helper is moved to sock.h to use mem_cgroup_from_sk(). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Link: https://patch.msgid.link/20250815201712.1745332-10-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-19net-memcg: Introduce mem_cgroup_sk_enabled().Kuniyuki Iwashima
The socket memcg feature is enabled by a static key and only works for non-root cgroup. We check both conditions in many places. Let's factorise it as a helper function. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Link: https://patch.msgid.link/20250815201712.1745332-8-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-06Merge tag 'kbuild-v6.17-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: "This is the last pull request from me. I'm grateful to have been able to continue as a maintainer for eight years. From the next cycle, Nathan and Nicolas will maintain Kbuild. - Fix a shortcut key issue in menuconfig - Fix missing rebuild of kheaders - Sort the symbol dump generated by gendwarfsyms - Support zboot extraction in scripts/extract-vmlinux - Migrate gconfig to GTK 3 - Add TAR variable to allow overriding the default tar command - Hand over Kbuild maintainership" * tag 'kbuild-v6.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (92 commits) MAINTAINERS: hand over Kbuild maintenance kheaders: make it possible to override TAR kbuild: userprogs: use correct linker when mixing clang and GNU ld kconfig: lxdialog: replace strcpy() with strncpy() in inputbox.c kconfig: lxdialog: replace strcpy with snprintf in print_autowrap kconfig: gconf: refactor text_insert_help() kconfig: gconf: remove unneeded variable in text_insert_msg kconfig: gconf: use hyphens in signals kconfig: gconf: replace GtkImageMenuItem with GtkMenuItem kconfig: gconf: Fix Back button behavior kconfig: gconf: fix single view to display dependent symbols correctly scripts: add zboot support to extract-vmlinux gendwarfksyms: order -T symtypes output by name gendwarfksyms: use preferred form of sizeof for allocation kconfig: qconf: confine {begin,end}Group to constructor and destructor kconfig: qconf: fix ConfigList::updateListAllforAll() kconfig: add a function to dump all menu entries in a tree-like format kconfig: gconf: show GTK version in About dialog kconfig: gconf: replace GtkHPaned and GtkVPaned with GtkPaned kconfig: gconf: replace GdkColor with GdkRGBA ...
2025-07-18net: track pfmemalloc drops via SKB_DROP_REASON_PFMEMALLOCJesper Dangaard Brouer
Add a new SKB drop reason (SKB_DROP_REASON_PFMEMALLOC) to track packets dropped due to memory pressure. In production environments, we've observed memory exhaustion reported by memory layer stack traces, but these drops were not properly tracked in the SKB drop reason infrastructure. While most network code paths now properly report pfmemalloc drops, some protocol-specific socket implementations still use sk_filter() without drop reason tracking: - Bluetooth L2CAP sockets - CAIF sockets - IUCV sockets - Netlink sockets - SCTP sockets - Unix domain sockets These remaining cases represent less common paths and could be converted in a follow-up patch if needed. The current implementation provides significantly improved observability into memory pressure events in the network stack, especially for key protocols like TCP and UDP, helping to diagnose problems in production environments. Reported-by: Matt Fleming <mfleming@cloudflare.com> Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Link: https://patch.msgid.link/175268316579.2407873.11634752355644843509.stgit@firesoul Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-07-02tcp: move tcp_memory_allocated into net_aligned_dataEric Dumazet
____cacheline_aligned_in_smp attribute only makes sure to align a field to a cache line. It does not prevent the linker to use the remaining of the cache line for other variables, causing potential false sharing. Move tcp_memory_allocated into a dedicated cache line. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250630093540.3052835-4-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-24module: remove meaningless 'name' parameter from __MODULE_INFO()Masahiro Yamada
The symbol names in the .modinfo section are never used and already randomized by the __UNIQUE_ID() macro. Therefore, the second parameter of __MODULE_INFO() is meaningless and can be removed to simplify the code. With this change, the symbol names in the .modinfo section will be prefixed with __UNIQUE_ID_modinfo, making it clearer that they originate from MODULE_INFO(). [Before] $ objcopy -j .modinfo vmlinux.o modinfo.o $ nm -n modinfo.o | head -n10 0000000000000000 r __UNIQUE_ID_license560 0000000000000011 r __UNIQUE_ID_file559 0000000000000030 r __UNIQUE_ID_description558 0000000000000074 r __UNIQUE_ID_license580 000000000000008e r __UNIQUE_ID_file579 00000000000000bd r __UNIQUE_ID_description578 00000000000000e6 r __UNIQUE_ID_license581 00000000000000ff r __UNIQUE_ID_file580 0000000000000134 r __UNIQUE_ID_description579 0000000000000179 r __UNIQUE_ID_uncore_no_discover578 [After] $ objcopy -j .modinfo vmlinux.o modinfo.o $ nm -n modinfo.o | head -n10 0000000000000000 r __UNIQUE_ID_modinfo560 0000000000000011 r __UNIQUE_ID_modinfo559 0000000000000030 r __UNIQUE_ID_modinfo558 0000000000000074 r __UNIQUE_ID_modinfo580 000000000000008e r __UNIQUE_ID_modinfo579 00000000000000bd r __UNIQUE_ID_modinfo578 00000000000000e6 r __UNIQUE_ID_modinfo581 00000000000000ff r __UNIQUE_ID_modinfo580 0000000000000134 r __UNIQUE_ID_modinfo579 0000000000000179 r __UNIQUE_ID_modinfo578 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
2025-06-17net: tcp: tsq: Convert from tasklet to BH workqueueTejun Heo
The only generic interface to execute asynchronously in the BH context is tasklet; however, it's marked deprecated and has some design flaws. To replace tasklets, BH workqueue support was recently added. A BH workqueue behaves similarly to regular workqueues except that the queued work items are executed in the BH context. This patch converts TCP Small Queues implementation from tasklet to BH workqueue. Semantically, this is an equivalent conversion and there shouldn't be any user-visible behavior changes. While workqueue's queueing and execution paths are a bit heavier than tasklet's, unless the work item is being queued every packet, the difference hopefully shouldn't matter. My experience with the networking stack is very limited and this patch definitely needs attention from someone who actually understands networking. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Cc: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/aFBeJ38AS1ZF3Dq5@slm.duckdns.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-17tcp: remove RFC3517/RFC6675 tcp_clear_retrans_hints_partial()Neal Cardwell
Now that we have removed the RFC3517/RFC6675 hints, tcp_clear_retrans_hints_partial() is empty, and can be removed. Suggested-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250615001435.2390793-4-ncardwell.sw@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-06-17tcp: remove RFC3517/RFC6675 hint state: lost_skb_hint, lost_cnt_hintNeal Cardwell
Now that obsolete RFC3517/RFC6675 TCP loss detection has been removed, we can remove the somewhat complex and intrusive code to maintain its hint state: lost_skb_hint and lost_cnt_hint. This commit makes tcp_clear_retrans_hints_partial() empty. We will remove tcp_clear_retrans_hints_partial() and its call sites in the next commit. Suggested-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250615001435.2390793-3-ncardwell.sw@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-10tcp: add TCP_RFC7323_TW_PAWS drop reasonJiayuan Chen
Devices in the networking path, such as firewalls, NATs, or routers, which can perform SNAT or DNAT, use addresses from their own limited address pools to masquerade the source address during forwarding, causing PAWS verification to fail more easily. Currently, packet loss statistics for PAWS can only be viewed through MIB, which is a global metric and cannot be precisely obtained through tracing to get the specific 4-tuple of the dropped packet. In the past, we had to use kprobe ret to retrieve relevant skb information from tcp_timewait_state_process(). We add a drop_reason pointer, similar to what previous commit does: commit e34100c2ecbb ("tcp: add a drop_reason pointer to tcp_check_req()") This commit addresses the PAWSESTABREJECTED case and also sets the corresponding drop reason. We use 'pwru' to test. Before this commit: '''' ./pwru 'port 9999' 2025/04/07 13:40:19 Listening for events.. TUPLE FUNC 172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_NOT_SPECIFIED) ''' After this commit: ''' ./pwru 'port 9999' 2025/04/07 13:51:34 Listening for events.. TUPLE FUNC 172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_TCP_RFC7323_TW_PAWS) ''' Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250409112614.16153-2-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-31Revert "tcp: avoid atomic operations on sk->sk_rmem_alloc"Eric Dumazet
This reverts commit 0de2a5c4b824da2205658ebebb99a55c43cdf60f. I forgot that a TCP socket could receive messages in its error queue. sock_queue_err_skb() can be called without socket lock being held, and changes sk->sk_rmem_alloc. The fact that skbs in error queue are limited by sk->sk_rcvbuf means that error messages can be dropped if socket receive queues are full, which is an orthogonal issue. In future kernels, we could use a separate sk->sk_error_mem_alloc counter specifically for the error queue. Fixes: 0de2a5c4b824 ("tcp: avoid atomic operations on sk->sk_rmem_alloc") Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250331075946.31960-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-25tcp: avoid atomic operations on sk->sk_rmem_allocEric Dumazet
TCP uses generic skb_set_owner_r() and sock_rfree() for received packets, with socket lock being owned. Switch to private versions, avoiding two atomic operations per packet. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250320121604.3342831-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-25tcp: support TCP_RTO_MIN_US for set/getsockopt useJason Xing
Support adjusting/reading RTO MIN for socket level by using set/getsockopt(). This new option has the same effect as TCP_BPF_RTO_MIN, which means it doesn't affect RTAX_RTO_MIN usage (by using ip route...). Considering that bpf option was implemented before this patch, so we need to use a standalone new option for pure tcp set/getsockopt() use. When the socket is created, its icsk_rto_min is set to the default value that is controlled by sysctl_tcp_rto_min_us. Then if application calls setsockopt() with TCP_RTO_MIN_US flag to pass a valid value, then icsk_rto_min will be overridden in jiffies unit. This patch adds WRITE_ONCE/READ_ONCE to avoid data-race around icsk_rto_min. Signed-off-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250317120314.41404-2-kerneljasonxing@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-24tcp: move icsk_clean_acked to a better locationEric Dumazet
As a followup of my presentation in Zagreb for netdev 0x19: icsk_clean_acked is only used by TCP when/if CONFIG_TLS_DEVICE is enabled from tcp_ack(). Rename it to tcp_clean_acked, move it to tcp_sock structure in the tcp_sock_read_rx for better cache locality in TCP fast path. Define this field only when CONFIG_TLS_DEVICE is enabled saving 8 bytes on configs not using it. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250317085313.2023214-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-17tcp: Pass flags to __tcp_send_ackIlpo Järvinen
Accurate ECN needs to send custom flags to handle IP-ECN field reflection during handshake. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17tcp: add new TCP_TW_ACK_OOW state and allow ECN bits in TOSIlpo Järvinen
ECN bits in TOS are always cleared when sending in ACKs in TW. Clearing them is problematic for TCP flows that used Accurate ECN because ECN bits decide which service queue the packet is placed into (L4S vs Classic). Effectively, TW ACKs are always downgraded from L4S to Classic queue which might impact, e.g., delay the ACK will experience on the path compared with the other packets of the flow. Change the TW ACK sending code to differentiate: - In tcp_v4_send_reset(), commit ba9e04a7ddf4f ("ip: fix tos reflection in ack and reset packets") cleans ECN bits for TW reset and this is not affected. - In tcp_v4_timewait_ack(), ECN bits for all TW ACKs are cleaned. But now only ECN bits of ACKs for oow data or paws_reject are cleaned, and ECN bits of other ACKs will not be cleaned. - In tcp_v4_reqsk_send_ack(), commit 66b13d99d96a1 ("ipv4: tcp: fix TOS value in ACK messages sent from TIME_WAIT") did not clean ECN bits of ACKs for oow data or paws_reject. But now the ECN bits rae cleaned for these ACKs. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17tcp: helpers for ECN mode handlingIlpo Järvinen
Create helpers for TCP ECN modes. No functional changes. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17tcp: extend TCP flags to allow AE bit/ACE fieldIlpo Järvinen
With AccECN, there's one additional TCP flag to be used (AE) and ACE field that overloads the definition of AE, CWR, and ECE flags. As tcp_flags was previously only 1 byte, the byte-order stuff needs to be added to it's handling. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17tcp: use BIT() macro in include/net/tcp.hChia-Yu Chang
Use BIT() macro for TCP flags field and TCP congestion control flags that will be used by the congestion control algorithm. No functional changes. Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Ilpo Järvinen <ij@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-07tcp: ulp: diag: more info without CAP_NET_ADMINMatthieu Baerts (NGI0)
When introduced in commit 61723b393292 ("tcp: ulp: add functions to dump ulp-specific information"), the whole ULP diag info has been exported only if the requester had CAP_NET_ADMIN. It looks like not everything is sensitive, and some info can be exported to all users in order to ease the debugging from the userspace side without requiring additional capabilities. Each layer should then decide what can be exposed to everybody. The 'net_admin' boolean is then passed to the different layers. On kTLS side, it looks like there is nothing sensitive there: version, cipher type, tx/rx user config type, plus some flags. So, only some metadata about the configuration, no cryptographic info like keys, etc. Then, everything can be exported to all users. On MPTCP side, that's different. The MPTCP-related sequence numbers per subflow should certainly not be exposed to everybody. For example, the DSS mapping and ssn_offset would give all users on the system access to narrow ranges of values for the subflow TCP sequence numbers and MPTCP-level DSNs, and then ease packet injection. The TCP diag interface doesn't expose the TCP sequence numbers for TCP sockets, so best to do the same here. The rest -- token, IDs, flags -- can be exported to everybody. Acked-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20250306-net-next-tcp-ulp-diag-net-admin-v1-2-06afdd860fc9@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-03tcp: add a drop_reason pointer to tcp_check_req()Eric Dumazet
We want to add new drop reasons for packets dropped in 3WHS in the following patches. tcp_rcv_state_process() has to set reason to TCP_FASTOPEN, because tcp_check_req() will conditionally overwrite the drop_reason. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250301201424.2046477-2-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-27Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.14-rc5). Conflicts: drivers/net/ethernet/cadence/macb_main.c fa52f15c745c ("net: cadence: macb: Synchronize stats calculations") 75696dd0fd72 ("net: cadence: macb: Convert to get_stats64") https://lore.kernel.org/20250224125848.68ee63e5@canb.auug.org.au Adjacent changes: drivers/net/ethernet/intel/ice/ice_sriov.c 79990cf5e7ad ("ice: Fix deinitializing VF in error path") a203163274a4 ("ice: simplify VF MSI-X managing") net/ipv4/tcp.c 18912c520674 ("tcp: devmem: don't write truncated dmabuf CMSGs to userspace") 297d389e9e5b ("net: prefix devmem specific helpers") net/mptcp/subflow.c 8668860b0ad3 ("mptcp: reset when MPTCP opts are dropped after join") c3349a22c200 ("mptcp: consolidate subflow cleanup") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-21Merge tag 'for-netdev' of ↵Jakub Kicinski
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Martin KaFai Lau says: ==================== pull-request: bpf-next 2025-02-20 We've added 19 non-merge commits during the last 8 day(s) which contain a total of 35 files changed, 1126 insertions(+), 53 deletions(-). The main changes are: 1) Add TCP_RTO_MAX_MS support to bpf_set/getsockopt, from Jason Xing 2) Add network TX timestamping support to BPF sock_ops, from Jason Xing 3) Add TX metadata Launch Time support, from Song Yoong Siang * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: igc: Add launch time support to XDP ZC igc: Refactor empty frame insertion for launch time support net: stmmac: Add launch time support to XDP ZC selftests/bpf: Add launch time request to xdp_hw_metadata xsk: Add launch time hardware offload support to XDP Tx metadata selftests/bpf: Add simple bpf tests in the tx path for timestamping feature bpf: Support selective sampling for bpf timestamping bpf: Add BPF_SOCK_OPS_TSTAMP_SENDMSG_CB callback bpf: Add BPF_SOCK_OPS_TSTAMP_ACK_CB callback bpf: Add BPF_SOCK_OPS_TSTAMP_SND_HW_CB callback bpf: Add BPF_SOCK_OPS_TSTAMP_SND_SW_CB callback bpf: Add BPF_SOCK_OPS_TSTAMP_SCHED_CB callback net-timestamp: Prepare for isolating two modes of SO_TIMESTAMPING bpf: Disable unsafe helpers in TX timestamping callbacks bpf: Prevent unsafe access to the sock fields in the BPF timestamping callback bpf: Prepare the sock_ops ctx and call bpf prog for TX timestamping bpf: Add networking timestamping support to bpf_get/setsockopt() selftests/bpf: Add rto max for bpf_setsockopt test bpf: Support TCP_RTO_MAX_MS for bpf_setsockopt ==================== Link: https://patch.msgid.link/20250221022104.386462-1-martin.lau@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-20Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfLinus Torvalds
Pull BPF fixes from Daniel Borkmann: - Fix a soft-lockup in BPF arena_map_free on 64k page size kernels (Alan Maguire) - Fix a missing allocation failure check in BPF verifier's acquire_lock_state (Kumar Kartikeya Dwivedi) - Fix a NULL-pointer dereference in trace_kfree_skb by adding kfree_skb to the raw_tp_null_args set (Kuniyuki Iwashima) - Fix a deadlock when freeing BPF cgroup storage (Abel Wu) - Fix a syzbot-reported deadlock when holding BPF map's freeze_mutex (Andrii Nakryiko) - Fix a use-after-free issue in bpf_test_init when eth_skb_pkt_type is accessing skb data not containing an Ethernet header (Shigeru Yoshida) - Fix skipping non-existing keys in generic_map_lookup_batch (Yan Zhai) - Several BPF sockmap fixes to address incorrect TCP copied_seq calculations, which prevented correct data reads from recv(2) in user space (Jiayuan Chen) - Two fixes for BPF map lookup nullness elision (Daniel Xu) - Fix a NULL-pointer dereference from vmlinux BTF lookup in bpf_sk_storage_tracing_allowed (Jared Kangas) * tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: selftests: bpf: test batch lookup on array of maps with holes bpf: skip non exist keys in generic_map_lookup_batch bpf: Handle allocation failure in acquire_lock_state bpf: verifier: Disambiguate get_constant_map_key() errors bpf: selftests: Test constant key extraction on irrelevant maps bpf: verifier: Do not extract constant map keys for irrelevant maps bpf: Fix softlockup in arena_map_free on 64k page kernel net: Add rx_skb of kfree_skb to raw_tp_null_args[]. bpf: Fix deadlock when freeing cgroup storage selftests/bpf: Add strparser test for bpf selftests/bpf: Fix invalid flag of recv() bpf: Disable non stream socket for strparser bpf: Fix wrong copied_seq calculation strparser: Add read_sock callback bpf: avoid holding freeze_mutex during mmap operation bpf: unify VM_WRITE vs VM_MAYWRITE use in BPF map mmaping logic selftests/bpf: Adjust data size to have ETH_HLEN bpf, test_run: Fix use-after-free issue in eth_skb_pkt_type() bpf: Remove unnecessary BTF lookups in bpf_sk_storage_tracing_allowed
2025-02-20bpf: Add BPF_SOCK_OPS_TSTAMP_ACK_CB callbackJason Xing
Support the ACK case for bpf timestamping. Add a new sock_ops callback, BPF_SOCK_OPS_TSTAMP_ACK_CB. This callback will occur at the same timestamping point as the user space's SCM_TSTAMP_ACK. The BPF program can use it to get the same SCM_TSTAMP_ACK timestamp without modifying the user-space application. This patch extends txstamp_ack to two bits: 1 stands for SO_TIMESTAMPING mode, 2 bpf extension. Signed-off-by: Jason Xing <kerneljasonxing@gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250220072940.99994-10-kerneljasonxing@gmail.com
2025-02-20bpf: Prevent unsafe access to the sock fields in the BPF timestamping callbackJason Xing
The subsequent patch will implement BPF TX timestamping. It will call the sockops BPF program without holding the sock lock. This breaks the current assumption that all sock ops programs will hold the sock lock. The sock's fields of the uapi's bpf_sock_ops requires this assumption. To address this, a new "u8 is_locked_tcp_sock;" field is added. This patch sets it in the current sock_ops callbacks. The "is_fullsock" test is then replaced by the "is_locked_tcp_sock" test during sock_ops_convert_ctx_access(). The new TX timestamping callbacks added in the subsequent patch will not have this set. This will prevent unsafe access from the new timestamping callbacks. Potentially, we could allow read-only access. However, this would require identifying which callback is read-safe-only and also requires additional BPF instruction rewrites in the covert_ctx. Since the BPF program can always read everything from a socket (e.g., by using bpf_core_cast), this patch keeps it simple and disables all read and write access to any socket fields through the bpf_sock_ops UAPI from the new TX timestamping callback. Moreover, note that some of the fields in bpf_sock_ops are specific to tcp_sock, and sock_ops currently only supports tcp_sock. In the future, UDP timestamping will be added, which will also break this assumption. The same idea used in this patch will be reused. Considering that the current sock_ops only supports tcp_sock, the variable is named is_locked_"tcp"_sock. Signed-off-by: Jason Xing <kerneljasonxing@gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://patch.msgid.link/20250220072940.99994-4-kerneljasonxing@gmail.com
2025-02-20Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.14-rc4). No conflicts or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-20tcp: drop secpath at the same time as we currently drop dstSabrina Dubroca
Xiumei reported hitting the WARN in xfrm6_tunnel_net_exit while running tests that boil down to: - create a pair of netns - run a basic TCP test over ipcomp6 - delete the pair of netns The xfrm_state found on spi_byaddr was not deleted at the time we delete the netns, because we still have a reference on it. This lingering reference comes from a secpath (which holds a ref on the xfrm_state), which is still attached to an skb. This skb is not leaked, it ends up on sk_receive_queue and then gets defer-free'd by skb_attempt_defer_free. The problem happens when we defer freeing an skb (push it on one CPU's defer_list), and don't flush that list before the netns is deleted. In that case, we still have a reference on the xfrm_state that we don't expect at this point. We already drop the skb's dst in the TCP receive path when it's no longer needed, so let's also drop the secpath. At this point, tcp_filter has already called into the LSM hooks that may require the secpath, so it should not be needed anymore. However, in some of those places, the MPTCP extension has just been attached to the skb, so we cannot simply drop all extensions. Fixes: 68822bdf76f1 ("net: generalize skb freeing deferral to per-cpu lists") Reported-by: Xiumei Mu <xmu@redhat.com> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/5055ba8f8f72bdcb602faa299faca73c280b7735.1739743613.git.sd@queasysnail.net Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-11tcp: add the ability to control max RTOEric Dumazet
Currently, TCP stack uses a constant (120 seconds) to limit the RTO value exponential growth. Some applications want to set a lower value. Add TCP_RTO_MAX_MS socket option to set a value (in ms) between 1 and 120 seconds. It is discouraged to change the socket rto max on a live socket, as it might lead to unexpected disconnects. Following patch is adding a netns sysctl to control the default value at socket creation time. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-11tcp: add a @pace_delay parameter to tcp_reset_xmit_timer()Eric Dumazet
We want to factorize calls to inet_csk_reset_xmit_timer(), to ease TCP_RTO_MAX change. Current users want to add tcp_pacing_delay(sk) to the timeout. Remaining calls to inet_csk_reset_xmit_timer() do not add the pacing delay. Following patch will convert them, passing false for @pace_delay. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-11tcp: remove tcp_reset_xmit_timer() @max_when argumentEric Dumazet
All callers use TCP_RTO_MAX, we can factorize this constant, becoming a variable soon. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-02-07tcp: rename inet_csk_{delete|reset}_keepalive_timer()Eric Dumazet
inet_csk_delete_keepalive_timer() and inet_csk_reset_keepalive_timer() are only used from core TCP, there is no need to export them. Replace their prefix by tcp. Move them to net/ipv4/tcp_timer.c and make tcp_delete_keepalive_timer() static. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Joe Damato <jdamato@fastly.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250206094605.2694118-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-01-29bpf: Fix wrong copied_seq calculationJiayuan Chen
'sk->copied_seq' was updated in the tcp_eat_skb() function when the action of a BPF program was SK_REDIRECT. For other actions, like SK_PASS, the update logic for 'sk->copied_seq' was moved to tcp_bpf_recvmsg_parser() to ensure the accuracy of the 'fionread' feature. It works for a single stream_verdict scenario, as it also modified sk_data_ready->sk_psock_verdict_data_ready->tcp_read_skb to remove updating 'sk->copied_seq'. However, for programs where both stream_parser and stream_verdict are active (strparser purpose), tcp_read_sock() was used instead of tcp_read_skb() (sk_data_ready->strp_data_ready->tcp_read_sock). tcp_read_sock() now still updates 'sk->copied_seq', leading to duplicate updates. In summary, for strparser + SK_PASS, copied_seq is redundantly calculated in both tcp_read_sock() and tcp_bpf_recvmsg_parser(). The issue causes incorrect copied_seq calculations, which prevent correct data reads from the recv() interface in user-land. We do not want to add new proto_ops to implement a new version of tcp_read_sock, as this would introduce code complexity [1]. We could have added noack and copied_seq to desc, and then called ops->read_sock. However, unfortunately, other modules didn’t fully initialize desc to zero. So, for now, we are directly calling tcp_read_sock_noack() in tcp_bpf.c. [1]: https://lore.kernel.org/bpf/20241218053408.437295-1-mrpre@163.com Fixes: e5c6de5fa025 ("bpf, sockmap: Incorrectly handling copied_seq") Suggested-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Jiayuan Chen <mrpre@163.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://patch.msgid.link/20250122100917.49845-3-mrpre@163.com
2024-12-09net: reformat kdoc return statementsJakub Kicinski
kernel-doc -Wall warns about missing Return: statement for non-void functions. We have a number of kdocs in our headers which are missing the colon, IOW they use * Return some value or * Returns some value Having the colon makes some sense, it should help kdoc parser avoid false positives. So add them. This is mostly done with a sed script, and removing the unnecessary cases (mostly the comments which aren't kdoc). Acked-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Richard Cochran <richardcochran@gmail.com> Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com> Reviewed-by: Edward Cree <ecree.xilinx@gmail.com> Acked-by: Alexandra Winter <wintera@linux.ibm.com> Acked-by: Pablo Neira Ayuso <pablo@netfilter.org> Link: https://patch.msgid.link/20241205165914.1071102-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-30tcp: add more warn of socket in tcp_send_loss_probe()Jason Xing
Add two fields to print in the helper which here covers tcp_send_loss_probe(). Link: https://lore.kernel.org/all/5632e043-bdba-4d75-bc7e-bf58014492fd@redhat.com/ Suggested-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Jason Xing <kernelxing@tencent.com> Cc: Neal Cardwell <ncardwell@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>