summaryrefslogtreecommitdiff
path: root/net/ipv4
AgeCommit message (Collapse)Author
2025-11-18tcp: Don't reinitialise tw->tw_transparent in tcp_time_wait().Kuniyuki Iwashima
tw->tw_transparent is initialised twice in inet_twsk_alloc() and tcp_time_wait(). Let's remove the latter. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Link: https://patch.msgid.link/20251118000445.4091280-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-17tcp: reduce tcp_comp_sack_slack_ns default value to 10 usecEric Dumazet
net.ipv4.tcp_comp_sack_slack_ns current default value is too high. When a flow has many drops (1 % or more), and small RTT, adding 100 usec before sending SACK stalls the sender relying on getting SACK fast enough to keep the pipe busy. Decrease the default to 10 usec. This is orthogonal to Congestion Control heuristics to determine if drops are caused by congestion or not. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Link: https://patch.msgid.link/20251114135141.3810964-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-14tcp: gro: inline tcp_gro_pull_header()Eric Dumazet
tcp_gro_pull_header() is used in GRO fast path, inline it. Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251113140358.58242-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-13Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.18-rc6). No conflicts, adjacent changes in: drivers/net/phy/micrel.c 96a9178a29a6 ("net: phy: micrel: lan8814 fix reset of the QSGMII interface") 61b7ade9ba8c ("net: phy: micrel: Add support for non PTP SKUs for lan8814") and a trivial one in tools/testing/selftests/drivers/net/Makefile. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-12ipv4: route: Prevent rt_bind_exception() from rebinding stale fnheChuang Wang
The sit driver's packet transmission path calls: sit_tunnel_xmit() -> update_or_create_fnhe(), which lead to fnhe_remove_oldest() being called to delete entries exceeding FNHE_RECLAIM_DEPTH+random. The race window is between fnhe_remove_oldest() selecting fnheX for deletion and the subsequent kfree_rcu(). During this time, the concurrent path's __mkroute_output() -> find_exception() can fetch the soon-to-be-deleted fnheX, and rt_bind_exception() then binds it with a new dst using a dst_hold(). When the original fnheX is freed via RCU, the dst reference remains permanently leaked. CPU 0 CPU 1 __mkroute_output() find_exception() [fnheX] update_or_create_fnhe() fnhe_remove_oldest() [fnheX] rt_bind_exception() [bind dst] RCU callback [fnheX freed, dst leak] This issue manifests as a device reference count leak and a warning in dmesg when unregistering the net device: unregister_netdevice: waiting for sitX to become free. Usage count = N Ido Schimmel provided the simple test validation method [1]. The fix clears 'oldest->fnhe_daddr' before calling fnhe_flush_routes(). Since rt_bind_exception() checks this field, setting it to zero prevents the stale fnhe from being reused and bound to a new dst just before it is freed. [1] ip netns add ns1 ip -n ns1 link set dev lo up ip -n ns1 address add 192.0.2.1/32 dev lo ip -n ns1 link add name dummy1 up type dummy ip -n ns1 route add 192.0.2.2/32 dev dummy1 ip -n ns1 link add name gretap1 up arp off type gretap \ local 192.0.2.1 remote 192.0.2.2 ip -n ns1 route add 198.51.0.0/16 dev gretap1 taskset -c 0 ip netns exec ns1 mausezahn gretap1 \ -A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q & taskset -c 2 ip netns exec ns1 mausezahn gretap1 \ -A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q & sleep 10 ip netns pids ns1 | xargs kill ip netns del ns1 Cc: stable@vger.kernel.org Fixes: 67d6d681e15b ("ipv4: make exception cache less predictible") Signed-off-by: Chuang Wang <nashuiliang@gmail.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251111064328.24440-1-nashuiliang@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-10net/smc: bpf: Introduce generic hook for handshake flowD. Wythe
The introduction of IPPROTO_SMC enables eBPF programs to determine whether to use SMC based on the context of socket creation, such as network namespaces, PID and comm name, etc. As a subsequent enhancement, to introduce a new generic hook that allows decisions on whether to use SMC or not at runtime, including but not limited to local/remote IP address or ports. User can write their own implememtion via bpf_struct_ops now to choose whether to use SMC or not before TCP 3rd handshake to be comleted. Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: Dust Li <dust.li@linux.alibaba.com> Link: https://patch.msgid.link/20251107035632.115950-3-alibuda@linux.alibaba.com
2025-11-07tcp: add net.ipv4.tcp_comp_sack_rtt_percentEric Dumazet
TCP SACK compression has been added in 2018 in commit 5d9f4262b7ea ("tcp: add SACK compression"). It is working great for WAN flows (with large RTT). Wifi in particular gets a significant boost _when_ ACK are suppressed. Add a new sysctl so that we can tune the very conservative 5 % value that has been used so far in this formula, so that small RTT flows can benefit from this feature. delay = min ( 5 % of RTT, 1 ms) This patch adds new tcp_comp_sack_rtt_percent sysctl to ease experiments and tuning. Given that we cap the delay to 1ms (tcp_comp_sack_delay_ns sysctl), set the default value to 33 %. Quoting Neal Cardwell ( https://lore.kernel.org/netdev/CADVnQymZ1tFnEA1Q=vtECs0=Db7zHQ8=+WCQtnhHFVbEOzjVnQ@mail.gmail.com/ ) The rationale for 33% is basically to try to facilitate pipelining, where there are always at least 3 ACKs and 3 GSO/TSO skbs per SRTT, so that the path can maintain a budget for 3 full-sized GSO/TSO skbs "in flight" at all times: + 1 skb in the qdisc waiting to be sent by the NIC next + 1 skb being sent by the NIC (being serialized by the NIC out onto the wire) + 1 skb being received and aggregated by the receiver machine's aggregation mechanism (some combination of LRO, GRO, and sack compression) Note that this is basically the same magic number (3) and the same rationales as: (a) tcp_tso_should_defer() ensuring that we defer sending data for no longer than cwnd/tcp_tso_win_divisor (where tcp_tso_win_divisor = 3), and (b) bbr_quantization_budget() ensuring that cwnd is at least 3 GSO/TSO skbs to maintain pipelining and full throughput at low RTTs Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Link: https://patch.msgid.link/20251106115236.3450026-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07tcp: Remove timeout arg from reqsk_timeout().Kuniyuki Iwashima
reqsk_timeout() is always called with @timeout being TCP_RTO_MAX. Let's remove the arg. As a prep for the next patch, reqsk_timeout() is moved to tcp.h and renamed to tcp_reqsk_timeout(). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251106003357.273403-5-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07tcp: Remove redundant init for req->num_timeout.Kuniyuki Iwashima
Commit 5903123f662e ("tcp: Use BPF timeout setting for SYN ACK RTO") introduced req->timeout and initialised it in 3 places: 1. reqsk_alloc() sets 0 2. inet_reqsk_alloc() sets TCP_TIMEOUT_INIT 3. tcp_conn_request() sets tcp_timeout_init() 1. has been always redundant as 2. overwrites it immediately. 2. was necessary for TFO SYN+ACK but is no longer needed after commit 8ea731d4c2ce ("tcp: Make SYN ACK RTO tunable by BPF programs with TFO"). 3. was moved to reqsk_queue_hash_req() in the previous patch. Now, we always initialise req->timeout just before scheduling the SYN+ACK timer: * For non-TFO SYN+ACK : reqsk_queue_hash_req() * For TFO SYN+ACK : tcp_fastopen_create_child() Let's remove the redundant initialisation of req->timeout in reqsk_alloc() and inet_reqsk_alloc(). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251106003357.273403-4-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07tcp: Remove timeout arg from reqsk_queue_hash_req().Kuniyuki Iwashima
inet_csk_reqsk_queue_hash_add() is no longer shared by DCCP. We do not need to pass req->timeout down to reqsk_queue_hash_req(). Let's move tcp_timeout_init() from tcp_conn_request() to reqsk_queue_hash_req(). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251106003357.273403-3-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07tcp: Call tcp_syn_ack_timeout() directly.Kuniyuki Iwashima
Since DCCP has been removed, we do not need to use request_sock_ops.syn_ack_timeout(). Let's call tcp_syn_ack_timeout() directly. Now other function pointers of request_sock_ops are protocol-dependent. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251106003357.273403-2-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04net: Convert struct sockaddr to fixed-size "sa_data[14]"Kees Cook
Revert struct sockaddr from flexible array to fixed 14-byte "sa_data", to solve over 36,000 -Wflex-array-member-not-at-end warnings, since struct sockaddr is embedded within many network structs. With socket/proto sockaddr-based internal APIs switched to use struct sockaddr_unsized, there should be no more uses of struct sockaddr that depend on reading beyond the end of struct sockaddr::sa_data that might trigger bounds checking. Comparing an x86_64 "allyesconfig" vmlinux build before and after this patch showed no new "ud1" instructions from CONFIG_UBSAN_BOUNDS nor any new "field-spanning" memcpy CONFIG_FORTIFY_SOURCE instrumentations. Cc: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20251104002617.2752303-8-kees@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04bpf: Convert cgroup sockaddr filters to use sockaddr_unsized consistentlyKees Cook
Update BPF cgroup sockaddr filtering infrastructure to use sockaddr_unsized consistently throughout the call chain, removing redundant explicit casts from callers. No binary changes expected. Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20251104002617.2752303-6-kees@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04net: Convert proto callbacks from sockaddr to sockaddr_unsizedKees Cook
Convert struct proto pre_connect(), connect(), bind(), and bind_add() callback function prototypes from struct sockaddr to struct sockaddr_unsized. This does not change per-implementation use of sockaddr for passing around an arbitrarily sized sockaddr struct. Those will be addressed in future patches. Additionally removes the no longer referenced struct sockaddr from include/net/inet_common.h. No binary changes expected. Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20251104002617.2752303-5-kees@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04net: Convert proto_ops connect() callbacks to use sockaddr_unsizedKees Cook
Update all struct proto_ops connect() callback function prototypes from "struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the compiler about object sizes. Calls into struct proto handlers gain casts that will be removed in the struct proto conversion patch. No binary changes expected. Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20251104002617.2752303-3-kees@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04net: Convert proto_ops bind() callbacks to use sockaddr_unsizedKees Cook
Update all struct proto_ops bind() callback function prototypes from "struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the compiler about object sizes. Calls into struct proto handlers gain casts that will be removed in the struct proto conversion patch. No binary changes expected. Signed-off-by: Kees Cook <kees@kernel.org> Link: https://patch.msgid.link/20251104002617.2752303-2-kees@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-31Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.18-rc4). No conflicts, adjacent changes: drivers/net/ethernet/stmicro/stmmac/stmmac_main.c ded9813d17d3 ("net: stmmac: Consider Tx VLAN offload tag length for maxSDU") 26ab9830beab ("net: stmmac: replace has_xxxx with core_type") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29ipv4: icmp: Add RFC 5837 supportIdo Schimmel
Add the ability to append the incoming IP interface information to ICMPv4 error messages in accordance with RFC 5837 and RFC 4884. This is required for more meaningful traceroute results in unnumbered networks. The feature is disabled by default and controlled via a new sysctl ("net.ipv4.icmp_errors_extension_mask") which accepts a bitmask of ICMP extensions to append to ICMP error messages. Currently, only a single value is supported, but the interface and the implementation should be able to support more extensions, if needed. Clone the skb and copy the relevant data portions before modifying the skb as the caller of __icmp_send() still owns the skb after the function returns. This should be fine since by default ICMP error messages are rate limited to 1000 per second and no more than 1 per second per specific host. Trim or pad the packet to 128 bytes before appending the ICMP extension structure in order to be compatible with legacy applications that assume that the ICMP extension structure always starts at this offset (the minimum length specified by RFC 4884). Reviewed-by: Petr Machata <petrm@nvidia.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251027082232.232571-2-idosch@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29tcp: fix too slow tcp_rcvbuf_grow() actionEric Dumazet
While the blamed commits apparently avoided an overshoot, they also limited how fast a sender can increase BDP at each RTT. This is not exactly a revert, we do not add the 16 * tp->advmss cushion we had, and we are keeping the out_of_order_queue contribution. Do the same in mptcp_rcvbuf_grow(). Tested: emulated 50ms rtt (tcp_stream --tcp-tx-delay 50000), cubic 20 second flow. net.ipv4.tcp_rmem set to "4096 131072 67000000" perf record -a -e tcp:tcp_rcvbuf_grow sleep 20 perf script Before: We can see we fail to roughly double RWIN at each RTT. Sender is RWIN limited while CWND is ramping up (before getting tcp_wmem limited). tcp_stream 33793 [010] 825.717525: tcp:tcp_rcvbuf_grow: time=100869 rtt_us=50428 copied=49152 inq=0 space=40960 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=103970 window_clamp=112128 rcv_wnd=106496 tcp_stream 33793 [010] 825.768966: tcp:tcp_rcvbuf_grow: time=51447 rtt_us=50362 copied=86016 inq=0 space=49152 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=107474 window_clamp=112128 rcv_wnd=106496 tcp_stream 33793 [010] 825.821539: tcp:tcp_rcvbuf_grow: time=52577 rtt_us=50243 copied=114688 inq=0 space=86016 ooo=0 scaling_ratio=219 rcvbuf=201096 rcv_ssthresh=167377 window_clamp=172031 rcv_wnd=167936 tcp_stream 33793 [010] 825.871781: tcp:tcp_rcvbuf_grow: time=50248 rtt_us=50237 copied=167936 inq=0 space=114688 ooo=0 scaling_ratio=219 rcvbuf=268129 rcv_ssthresh=224722 window_clamp=229375 rcv_wnd=225280 tcp_stream 33793 [010] 825.922475: tcp:tcp_rcvbuf_grow: time=50698 rtt_us=50183 copied=241664 inq=0 space=167936 ooo=0 scaling_ratio=219 rcvbuf=392617 rcv_ssthresh=331217 window_clamp=335871 rcv_wnd=323584 tcp_stream 33793 [010] 825.973326: tcp:tcp_rcvbuf_grow: time=50855 rtt_us=50213 copied=339968 inq=0 space=241664 ooo=0 scaling_ratio=219 rcvbuf=564986 rcv_ssthresh=478674 window_clamp=483327 rcv_wnd=462848 tcp_stream 33793 [010] 826.023970: tcp:tcp_rcvbuf_grow: time=50647 rtt_us=50248 copied=491520 inq=0 space=339968 ooo=0 scaling_ratio=219 rcvbuf=794811 rcv_ssthresh=671778 window_clamp=679935 rcv_wnd=651264 tcp_stream 33793 [010] 826.074612: tcp:tcp_rcvbuf_grow: time=50648 rtt_us=50227 copied=700416 inq=0 space=491520 ooo=0 scaling_ratio=219 rcvbuf=1149124 rcv_ssthresh=974881 window_clamp=983039 rcv_wnd=942080 tcp_stream 33793 [010] 826.125452: tcp:tcp_rcvbuf_grow: time=50845 rtt_us=50225 copied=987136 inq=8192 space=700416 ooo=0 scaling_ratio=219 rcvbuf=1637502 rcv_ssthresh=1392674 window_clamp=1400831 rcv_wnd=1339392 tcp_stream 33793 [010] 826.175698: tcp:tcp_rcvbuf_grow: time=50250 rtt_us=50198 copied=1347584 inq=0 space=978944 ooo=0 scaling_ratio=219 rcvbuf=2288672 rcv_ssthresh=1949729 window_clamp=1957887 rcv_wnd=1945600 tcp_stream 33793 [010] 826.225947: tcp:tcp_rcvbuf_grow: time=50252 rtt_us=50240 copied=1945600 inq=0 space=1347584 ooo=0 scaling_ratio=219 rcvbuf=3150516 rcv_ssthresh=2687010 window_clamp=2695167 rcv_wnd=2691072 tcp_stream 33793 [010] 826.276175: tcp:tcp_rcvbuf_grow: time=50233 rtt_us=50224 copied=2691072 inq=0 space=1945600 ooo=0 scaling_ratio=219 rcvbuf=4548617 rcv_ssthresh=3883041 window_clamp=3891199 rcv_wnd=3887104 tcp_stream 33793 [010] 826.326403: tcp:tcp_rcvbuf_grow: time=50233 rtt_us=50229 copied=3887104 inq=0 space=2691072 ooo=0 scaling_ratio=219 rcvbuf=6291456 rcv_ssthresh=5370482 window_clamp=5382144 rcv_wnd=5373952 tcp_stream 33793 [010] 826.376723: tcp:tcp_rcvbuf_grow: time=50323 rtt_us=50218 copied=5373952 inq=0 space=3887104 ooo=0 scaling_ratio=219 rcvbuf=9087658 rcv_ssthresh=7755537 window_clamp=7774207 rcv_wnd=7757824 tcp_stream 33793 [010] 826.426991: tcp:tcp_rcvbuf_grow: time=50274 rtt_us=50196 copied=7757824 inq=180224 space=5373952 ooo=0 scaling_ratio=219 rcvbuf=12563759 rcv_ssthresh=10729233 window_clamp=10747903 rcv_wnd=10575872 tcp_stream 33793 [010] 826.477229: tcp:tcp_rcvbuf_grow: time=50241 rtt_us=50078 copied=10731520 inq=180224 space=7577600 ooo=0 scaling_ratio=219 rcvbuf=17715667 rcv_ssthresh=15136529 window_clamp=15155199 rcv_wnd=14983168 tcp_stream 33793 [010] 826.527482: tcp:tcp_rcvbuf_grow: time=50258 rtt_us=50153 copied=15138816 inq=360448 space=10551296 ooo=0 scaling_ratio=219 rcvbuf=24667870 rcv_ssthresh=21073410 window_clamp=21102591 rcv_wnd=20766720 tcp_stream 33793 [010] 826.577712: tcp:tcp_rcvbuf_grow: time=50234 rtt_us=50228 copied=21073920 inq=0 space=14778368 ooo=0 scaling_ratio=219 rcvbuf=34550339 rcv_ssthresh=29517041 window_clamp=29556735 rcv_wnd=29519872 tcp_stream 33793 [010] 826.627982: tcp:tcp_rcvbuf_grow: time=50275 rtt_us=50220 copied=29519872 inq=540672 space=21073920 ooo=0 scaling_ratio=219 rcvbuf=49268707 rcv_ssthresh=42090625 window_clamp=42147839 rcv_wnd=41627648 tcp_stream 33793 [010] 826.678274: tcp:tcp_rcvbuf_grow: time=50296 rtt_us=50185 copied=42053632 inq=761856 space=28979200 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57238168 window_clamp=57316406 rcv_wnd=56606720 tcp_stream 33793 [010] 826.728627: tcp:tcp_rcvbuf_grow: time=50357 rtt_us=50128 copied=43913216 inq=851968 space=41291776 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56524800 tcp_stream 33793 [010] 827.131364: tcp:tcp_rcvbuf_grow: time=50239 rtt_us=50127 copied=43843584 inq=655360 space=43061248 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56696832 tcp_stream 33793 [010] 827.181613: tcp:tcp_rcvbuf_grow: time=50254 rtt_us=50115 copied=43843584 inq=524288 space=43188224 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56807424 tcp_stream 33793 [010] 828.339635: tcp:tcp_rcvbuf_grow: time=50283 rtt_us=50110 copied=43843584 inq=458752 space=43319296 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56864768 tcp_stream 33793 [010] 828.440350: tcp:tcp_rcvbuf_grow: time=50404 rtt_us=50099 copied=43843584 inq=393216 space=43384832 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=56922112 tcp_stream 33793 [010] 829.195106: tcp:tcp_rcvbuf_grow: time=50154 rtt_us=50077 copied=43843584 inq=196608 space=43450368 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57290728 window_clamp=57316406 rcv_wnd=57090048 After: It takes few steps to increase RWIN. Sender is no longer RWIN limited. tcp_stream 50826 [010] 935.634212: tcp:tcp_rcvbuf_grow: time=100788 rtt_us=50315 copied=49152 inq=0 space=40960 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=103970 window_clamp=112128 rcv_wnd=106496 tcp_stream 50826 [010] 935.685642: tcp:tcp_rcvbuf_grow: time=51437 rtt_us=50361 copied=86016 inq=0 space=49152 ooo=0 scaling_ratio=219 rcvbuf=160875 rcv_ssthresh=132969 window_clamp=137623 rcv_wnd=131072 tcp_stream 50826 [010] 935.738299: tcp:tcp_rcvbuf_grow: time=52660 rtt_us=50256 copied=139264 inq=0 space=86016 ooo=0 scaling_ratio=219 rcvbuf=502741 rcv_ssthresh=411497 window_clamp=430079 rcv_wnd=413696 tcp_stream 50826 [010] 935.788544: tcp:tcp_rcvbuf_grow: time=50249 rtt_us=50233 copied=307200 inq=0 space=139264 ooo=0 scaling_ratio=219 rcvbuf=728690 rcv_ssthresh=618717 window_clamp=623371 rcv_wnd=618496 tcp_stream 50826 [010] 935.838796: tcp:tcp_rcvbuf_grow: time=50258 rtt_us=50202 copied=618496 inq=0 space=307200 ooo=0 scaling_ratio=219 rcvbuf=2450338 rcv_ssthresh=1855709 window_clamp=2096187 rcv_wnd=1859584 tcp_stream 50826 [010] 935.889140: tcp:tcp_rcvbuf_grow: time=50347 rtt_us=50166 copied=1261568 inq=0 space=618496 ooo=0 scaling_ratio=219 rcvbuf=4376503 rcv_ssthresh=3725291 window_clamp=3743961 rcv_wnd=3706880 tcp_stream 50826 [010] 935.939435: tcp:tcp_rcvbuf_grow: time=50300 rtt_us=50185 copied=2478080 inq=24576 space=1261568 ooo=0 scaling_ratio=219 rcvbuf=9082648 rcv_ssthresh=7733731 window_clamp=7769921 rcv_wnd=7692288 tcp_stream 50826 [010] 935.989681: tcp:tcp_rcvbuf_grow: time=50251 rtt_us=50221 copied=4915200 inq=114688 space=2453504 ooo=0 scaling_ratio=219 rcvbuf=16574936 rcv_ssthresh=14108110 window_clamp=14179339 rcv_wnd=14024704 tcp_stream 50826 [010] 936.039967: tcp:tcp_rcvbuf_grow: time=50289 rtt_us=50279 copied=9830400 inq=114688 space=4800512 ooo=0 scaling_ratio=219 rcvbuf=32695050 rcv_ssthresh=27896187 window_clamp=27969593 rcv_wnd=27815936 tcp_stream 50826 [010] 936.090172: tcp:tcp_rcvbuf_grow: time=50211 rtt_us=50200 copied=19841024 inq=114688 space=9715712 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57245176 window_clamp=57316406 rcv_wnd=57163776 tcp_stream 50826 [010] 936.140430: tcp:tcp_rcvbuf_grow: time=50262 rtt_us=50197 copied=39501824 inq=114688 space=19726336 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57245176 window_clamp=57316406 rcv_wnd=57163776 tcp_stream 50826 [010] 936.190527: tcp:tcp_rcvbuf_grow: time=50101 rtt_us=50071 copied=43655168 inq=262144 space=39387136 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57032704 tcp_stream 50826 [010] 936.240719: tcp:tcp_rcvbuf_grow: time=50197 rtt_us=50057 copied=43843584 inq=262144 space=43393024 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57032704 tcp_stream 50826 [010] 936.341271: tcp:tcp_rcvbuf_grow: time=50297 rtt_us=50123 copied=43843584 inq=131072 space=43581440 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57147392 tcp_stream 50826 [010] 936.642503: tcp:tcp_rcvbuf_grow: time=50131 rtt_us=50084 copied=43843584 inq=0 space=43712512 ooo=0 scaling_ratio=219 rcvbuf=67000000 rcv_ssthresh=57259192 window_clamp=57316406 rcv_wnd=57262080 Fixes: 65c5287892e9 ("tcp: fix sk_rcvbuf overshoot") Fixes: e118cdc34dd1 ("mptcp: rcvbuf auto-tuning improvement") Reported-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/589 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-v3-4-74b43ba4c84c@kernel.org Signed-off-by: Jakub Kicinski <kuba@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>
2025-10-29net: ipv4: Remove extern udp_v4_early_demux()/tcp_v4_early_demux() in .c filesWang Liang
Function udp_v4_early_demux() was already declared in 'include/net/udp.h', no need to keep the extern in 'ip_input.c', which may produce the following checkpatch warning: WARNING: externs should be avoided in .c files #45: FILE: net/ipv4/ip_input.c:322: +enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb); Replace it by including 'net/udp.h'. Do the same for tcp_v4_early_demux(). Signed-off-by: Wang Liang <wangliang74@huawei.com> Link: https://patch.msgid.link/20251025092637.1020960-1-wangliang74@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-28net: tcp_lp: fix kernel-doc warnings and update outdated reference linksRakuram Eswaran
Fix kernel-doc warnings in tcp_lp.c by adding missing parameter descriptions for tcp_lp_cong_avoid() and tcp_lp_pkts_acked() when building with W=1. Also replace invalid URLs in the file header comment with the currently valid links to the TCP-LP paper and implementation page. No functional changes. Signed-off-by: Rakuram Eswaran <rakuram.e96@gmail.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20251025-net_ipv4_tcp_lp_c-v1-1-058cc221499e@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-27tcp: remove one ktime_get() from recvmsg() fast pathEric Dumazet
Each time some payload is consumed by user space (recvmsg() and friends), TCP calls tcp_rcv_space_adjust() to run DRS algorithm to check if an increase of sk->sk_rcvbuf is needed. This function is based on time sampling, and currently calls tcp_mstamp_refresh(tp), which is a wrapper around ktime_get_ns(). ktime_get_ns() has a high cost on some platforms. 100+ cycles for rdtscp on AMD EPYC Turin for instance. We do not have to refresh tp->tcp_mpstamp, using the last cached value is enough. We only need to refresh it from __tcp_cleanup_rbuf() if an ACK must be sent (this is a rare event). Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20251024120707.3516550-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-27sctp: Use sctp_clone_sock() in sctp_do_peeloff().Kuniyuki Iwashima
sctp_do_peeloff() calls sock_create() to allocate and initialise struct sock, inet_sock, and sctp_sock, but later sctp_copy_sock() and sctp_sock_migrate() overwrite most fields. What sctp_do_peeloff() does is more like accept(). Let's use sock_create_lite() and sctp_clone_sock(). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20251023231751.4168390-8-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-27sctp: Use sk_clone() in sctp_accept().Kuniyuki Iwashima
sctp_accept() calls sctp_v[46]_create_accept_sk() to allocate a new socket and calls sctp_sock_migrate() to copy fields from the parent socket to the new socket. sctp_v4_create_accept_sk() allocates sk by sk_alloc(), initialises it by sock_init_data(), and copy a bunch of fields from the parent socekt by sctp_copy_sock(). sctp_sock_migrate() calls sctp_copy_descendant() to copy most fields in sctp_sock from the parent socket by memcpy(). These can be simply replaced by sk_clone(). Let's consolidate sctp_v[46]_create_accept_sk() to sctp_clone_sock() with sk_clone(). We will reuse sctp_clone_sock() for sctp_do_peeloff() and then remove sctp_copy_descendant(). Note that sock_reset_flag(newsk, SOCK_ZAPPED) is not copied to sctp_clone_sock() as sctp does not use SOCK_ZAPPED at all. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Acked-by: Xin Long <lucien.xin@gmail.com> Link: https://patch.msgid.link/20251023231751.4168390-6-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-24neighbour: Convert rwlock of struct neigh_table to spinlock.Kuniyuki Iwashima
Only neigh_for_each() and neigh_seq_start/stop() are on the reader side of neigh_table.lock. Let's convert rwlock to the plain spinlock. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251022054004.2514876-6-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-23tcp: Remove unnecessary null check in tcp_inbound_md5_hash()Eric Biggers
The 'if (!key && hash_location)' check in tcp_inbound_md5_hash() implies that hash_location might be null. However, later code in the function dereferences hash_location anyway, without checking for null first. Fortunately, there is no real bug, since tcp_inbound_md5_hash() is called only with non-null values of hash_location. Therefore, remove the unnecessary and misleading null check of hash_location. This silences a Smatch static checker warning (https://lore.kernel.org/netdev/aPi4b6aWBbBR52P1@stanley.mountain/) Also fix the related comment at the beginning of the function. Signed-off-by: Eric Biggers <ebiggers@kernel.org> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Link: https://patch.msgid.link/20251022221209.19716-1-ebiggers@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-17Merge 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 2025-10-16 We've added 6 non-merge commits during the last 1 day(s) which contain a total of 18 files changed, 577 insertions(+), 38 deletions(-). The main changes are: 1) Bypass the global per-protocol memory accounting either by setting a netns sysctl or using bpf_setsockopt in a bpf program, from Kuniyuki Iwashima. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: selftests/bpf: Add test for sk->sk_bypass_prot_mem. bpf: Introduce SK_BPF_BYPASS_PROT_MEM. bpf: Support bpf_setsockopt() for BPF_CGROUP_INET_SOCK_CREATE. net: Introduce net.core.bypass_prot_mem sysctl. net: Allow opt-out from global protocol memory accounting. tcp: Save lock_sock() for memcg in inet_csk_accept(). ==================== Link: https://patch.msgid.link/20251016204539.773707-1-martin.lau@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-17tcp: Convert tcp-md5 to use MD5 library instead of crypto_ahashEric Biggers
Make tcp-md5 use the MD5 library API (added in 6.18) instead of the crypto_ahash API. This is much simpler and also more efficient: - The library API just operates on struct md5_ctx. Just allocate this struct on the stack instead of using a pool of pre-allocated crypto_ahash and ahash_request objects. - The library API accepts standard pointers and doesn't require scatterlists. So, for hashing the headers just use an on-stack buffer instead of a pool of pre-allocated kmalloc'ed scratch buffers. - The library API never fails. Therefore, checking for MD5 hashing errors is no longer necessary. Update tcp_v4_md5_hash_skb(), tcp_v6_md5_hash_skb(), tcp_v4_md5_hash_hdr(), tcp_v6_md5_hash_hdr(), tcp_md5_hash_key(), tcp_sock_af_ops::calc_md5_hash, and tcp_request_sock_ops::calc_md5_hash to return void instead of int. - The library API provides direct access to the MD5 code, eliminating unnecessary overhead such as indirect function calls and scatterlist management. Microbenchmarks of tcp_v4_md5_hash_skb() on x86_64 show a speedup from 7518 to 7041 cycles (6% fewer) with skb->len == 1440, or from 1020 to 678 cycles (33% fewer) with skb->len == 140. Since tcp_sigpool_hash_skb_data() can no longer be used, add a function tcp_md5_hash_skb_data() which is specialized to MD5. Of course, to the extent that this duplicates any code, it's well worth it. To preserve the existing behavior of TCP-MD5 support being disabled when the kernel is booted with "fips=1", make tcp_md5_do_add() check fips_enabled itself. Previously it relied on the error from crypto_alloc_ahash("md5") being bubbled up. I don't know for sure that this is actually needed, but this preserves the existing behavior. Tested with bidirectional TCP-MD5, both IPv4 and IPv6, between a kernel that includes this commit and a kernel that doesn't include this commit. (Side note: please don't use TCP-MD5! It's cryptographically weak. But as long as Linux supports it, it might as well be implemented properly.) Signed-off-by: Eric Biggers <ebiggers@kernel.org> Link: https://patch.msgid.link/20251014215836.115616-1-ebiggers@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-17inet: Avoid ehash lookup race in inet_twsk_hashdance_schedule()Xuanqiang Luo
Since ehash lookups are lockless, if another CPU is converting sk to tw concurrently, fetching the newly inserted tw with tw->tw_refcnt == 0 cause lookup failure. The call trace map is drawn as follows: CPU 0 CPU 1 ----- ----- inet_twsk_hashdance_schedule() spin_lock() inet_twsk_add_node_rcu(tw, ...) __inet_lookup_established() (find tw, failure due to tw_refcnt = 0) __sk_nulls_del_node_init_rcu(sk) refcount_set(&tw->tw_refcnt, 3) spin_unlock() By replacing sk with tw atomically via hlist_nulls_replace_init_rcu() after setting tw_refcnt, we ensure that tw is either fully initialized or not visible to other CPUs, eliminating the race. It's worth noting that we held lock_sock() before the replacement, so there's no need to check if sk is hashed. Thanks to Kuniyuki Iwashima! Fixes: 3ab5aee7fe84 ("net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls") Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev> Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251015020236.431822-4-xuanqiang.luo@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-17inet: Avoid ehash lookup race in inet_ehash_insert()Xuanqiang Luo
Since ehash lookups are lockless, if one CPU performs a lookup while another concurrently deletes and inserts (removing reqsk and inserting sk), the lookup may fail to find the socket, an RST may be sent. The call trace map is drawn as follows: CPU 0 CPU 1 ----- ----- inet_ehash_insert() spin_lock() sk_nulls_del_node_init_rcu(osk) __inet_lookup_established() (lookup failed) __sk_nulls_add_node_rcu(sk, list) spin_unlock() As both deletion and insertion operate on the same ehash chain, this patch introduces a new sk_nulls_replace_node_init_rcu() helper functions to implement atomic replacement. Fixes: 5e0724d027f0 ("tcp/dccp: fix hashdance race for passive sessions") Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev> Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251015020236.431822-3-xuanqiang.luo@linux.dev Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-16net: Allow opt-out from global protocol memory accounting.Kuniyuki Iwashima
Some protocols (e.g., TCP, UDP) implement memory accounting for socket buffers and charge memory to per-protocol global counters pointed to by sk->sk_proto->memory_allocated. Sometimes, system processes do not want that limitation. For a similar purpose, there is SO_RESERVE_MEM for sockets under memcg. Also, by opting out of the per-protocol accounting, sockets under memcg can avoid paying costs for two orthogonal memory accounting mechanisms. A microbenchmark result is in the subsequent bpf patch. Let's allow opt-out from the per-protocol memory accounting if sk->sk_bypass_prot_mem is true. sk->sk_bypass_prot_mem and sk->sk_prot are placed in the same cache line, and sk_has_account() always fetches sk->sk_prot before accessing sk->sk_bypass_prot_mem, so there is no extra cache miss for this patch. The following patches will set sk->sk_bypass_prot_mem to true, and then, the per-protocol memory accounting will be skipped. Note that this does NOT disable memcg, but rather the per-protocol one. Another option not to use the hole in struct sock_common is create sk_prot variants like tcp_prot_bypass, but this would complicate SOCKMAP logic, tcp_bpf_prots etc. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Link: https://patch.msgid.link/20251014235604.3057003-3-kuniyu@google.com
2025-10-16tcp: Save lock_sock() for memcg in inet_csk_accept().Kuniyuki Iwashima
If memcg is enabled, accept() acquires lock_sock() twice for each new TCP/MPTCP socket in inet_csk_accept() and __inet_accept(). Let's move memcg operations from inet_csk_accept() to __inet_accept(). Note that SCTP somehow allocates a new socket by sk_alloc() in sk->sk_prot->accept() and clones fields manually, instead of using sk_clone_lock(). mem_cgroup_sk_alloc() is called for SCTP before __inet_accept(), so I added the protocol check in __inet_accept(), but this can be removed once SCTP uses sk_clone_lock(). Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Link: https://patch.msgid.link/20251014235604.3057003-2-kuniyu@google.com
2025-10-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.18-rc2). No conflicts or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-16udp: do not use skb_release_head_state() before skb_attempt_defer_free()Eric Dumazet
Michal reported and bisected an issue after recent adoption of skb_attempt_defer_free() in UDP. The issue here is that skb_release_head_state() is called twice per skb, one time from skb_consume_udp(), then a second time from skb_defer_free_flush() and napi_consume_skb(). As Sabrina suggested, remove skb_release_head_state() call from skb_consume_udp(). Add a DEBUG_NET_WARN_ON_ONCE(skb_nfct(skb)) in skb_attempt_defer_free() Many thanks to Michal, Sabrina, Paolo and Florian for their help. Fixes: 6471658dc66c ("udp: use skb_attempt_defer_free()") Reported-and-bisected-by: Michal Kubecek <mkubecek@suse.cz> Closes: https://lore.kernel.org/netdev/gpjh4lrotyephiqpuldtxxizrsg6job7cvhiqrw72saz2ubs3h@g6fgbvexgl3r/ Signed-off-by: Eric Dumazet <edumazet@google.com> Tested-by: Michal Kubecek <mkubecek@suse.cz> Cc: Sabrina Dubroca <sd@queasysnail.net> Cc: Florian Westphal <fw@strlen.de> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Link: https://patch.msgid.link/20251015052715.4140493-1-edumazet@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-10-15tcp: better handle TCP_TX_DELAY on established flowsEric Dumazet
Some applications uses TCP_TX_DELAY socket option after TCP flow is established. Some metrics need to be updated, otherwise TCP might take time to adapt to the new (emulated) RTT. This patch adjusts tp->srtt_us, tp->rtt_min, icsk_rto and sk->sk_pacing_rate. This is best effort, and for instance icsk_rto is reset without taking backoff into account. Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251013145926.833198-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-14tcp: fix tcp_tso_should_defer() vs large RTTEric Dumazet
Neal reported that using neper tcp_stream with TCP_TX_DELAY set to 50ms would often lead to flows stuck in a small cwnd mode, regardless of the congestion control. While tcp_stream sets TCP_TX_DELAY too late after the connect(), it highlighted two kernel bugs. The following heuristic in tcp_tso_should_defer() seems wrong for large RTT: delta = tp->tcp_clock_cache - head->tstamp; /* If next ACK is likely to come too late (half srtt), do not defer */ if ((s64)(delta - (u64)NSEC_PER_USEC * (tp->srtt_us >> 4)) < 0) goto send_now; If next ACK is expected to come in more than 1 ms, we should not defer because we prefer a smooth ACK clocking. While blamed commit was a step in the good direction, it was not generic enough. Another patch fixing TCP_TX_DELAY for established flows will be proposed when net-next reopens. Fixes: 50c8339e9299 ("tcp: tso: restore IW10 after TSO autosizing") Reported-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Tested-by: Neal Cardwell <ncardwell@google.com> Link: https://patch.msgid.link/20251011115742.1245771-1-edumazet@google.com [pabeni@redhat.com: fixed whitespace issue] Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-10-13net/ip6_tunnel: Prevent perpetual tunnel growthDmitry Safonov
Similarly to ipv4 tunnel, ipv6 version updates dev->needed_headroom, too. While ipv4 tunnel headroom adjustment growth was limited in commit 5ae1e9922bbd ("net: ip_tunnel: prevent perpetual headroom growth"), ipv6 tunnel yet increases the headroom without any ceiling. Reflect ipv4 tunnel headroom adjustment limit on ipv6 version. Credits to Francesco Ruggeri, who was originally debugging this issue and wrote local Arista-specific patch and a reproducer. Fixes: 8eb30be0352d ("ipv6: Create ip6_tnl_xmit") Cc: Florian Westphal <fw@strlen.de> Cc: Francesco Ruggeri <fruggeri05@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Link: https://patch.msgid.link/20251009-ip6_tunnel-headroom-v2-1-8e4dbd8f7e35@arista.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-06tcp: take care of zero tp->window_clamp in tcp_set_rcvlowat()Eric Dumazet
Some applications (like selftests/net/tcp_mmap.c) call SO_RCVLOWAT on their listener, before accept(). This has an unfortunate effect on wscale selection in tcp_select_initial_window() during 3WHS. For instance, tcp_mmap was negotiating wscale 4, regardless of tcp_rmem[2] and sysctl_rmem_max. Do not change tp->window_clamp if it is zero or bigger than our computed value. Zero value is special, it allows tcp_select_initial_window() to enable autotuning. Note that SO_RCVLOWAT use on listener is probably not wise, because tp->scaling_ratio has a default value, possibly wrong. Fixes: d1361840f8c5 ("tcp: fix SO_RCVLOWAT and RCVBUF autotuning") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Link: https://patch.msgid.link/20251003184119.2526655-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-06tcp: Don't call reqsk_fastopen_remove() in tcp_conn_request().Kuniyuki Iwashima
syzbot reported the splat below in tcp_conn_request(). [0] If a listener is close()d while a TFO socket is being processed in tcp_conn_request(), inet_csk_reqsk_queue_add() does not set reqsk->sk and calls inet_child_forget(), which calls tcp_disconnect() for the TFO socket. After the cited commit, tcp_disconnect() calls reqsk_fastopen_remove(), where reqsk_put() is called due to !reqsk->sk. Then, reqsk_fastopen_remove() in tcp_conn_request() decrements the last req->rsk_refcnt and frees reqsk, and __reqsk_free() at the drop_and_free label causes the refcount underflow for the listener and double-free of the reqsk. Let's remove reqsk_fastopen_remove() in tcp_conn_request(). Note that other callers make sure tp->fastopen_rsk is not NULL. [0]: refcount_t: underflow; use-after-free. WARNING: CPU: 12 PID: 5563 at lib/refcount.c:28 refcount_warn_saturate (lib/refcount.c:28) Modules linked in: CPU: 12 UID: 0 PID: 5563 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:refcount_warn_saturate (lib/refcount.c:28) Code: ab e8 8e b4 98 ff 0f 0b c3 cc cc cc cc cc 80 3d a4 e4 d6 01 00 75 9c c6 05 9b e4 d6 01 01 48 c7 c7 e8 df fb ab e8 6a b4 98 ff <0f> 0b e9 03 5b 76 00 cc 80 3d 7d e4 d6 01 00 0f 85 74 ff ff ff c6 RSP: 0018:ffffa79fc0304a98 EFLAGS: 00010246 RAX: d83af4db1c6b3900 RBX: ffff9f65c7a69020 RCX: d83af4db1c6b3900 RDX: 0000000000000000 RSI: 00000000ffff7fff RDI: ffffffffac78a280 RBP: 000000009d781b60 R08: 0000000000007fff R09: ffffffffac6ca280 R10: 0000000000017ffd R11: 0000000000000004 R12: ffff9f65c7b4f100 R13: ffff9f65c7d23c00 R14: ffff9f65c7d26000 R15: ffff9f65c7a64ef8 FS: 00007f9f962176c0(0000) GS:ffff9f65fcf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000180 CR3: 000000000dbbe006 CR4: 0000000000372ef0 Call Trace: <IRQ> tcp_conn_request (./include/linux/refcount.h:400 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 ./include/net/sock.h:1965 ./include/net/request_sock.h:131 net/ipv4/tcp_input.c:7301) tcp_rcv_state_process (net/ipv4/tcp_input.c:6708) tcp_v6_do_rcv (net/ipv6/tcp_ipv6.c:1670) tcp_v6_rcv (net/ipv6/tcp_ipv6.c:1906) ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:438) ip6_input (net/ipv6/ip6_input.c:500) ipv6_rcv (net/ipv6/ip6_input.c:311) __netif_receive_skb (net/core/dev.c:6104) process_backlog (net/core/dev.c:6456) __napi_poll (net/core/dev.c:7506) net_rx_action (net/core/dev.c:7569 net/core/dev.c:7696) handle_softirqs (kernel/softirq.c:579) do_softirq (kernel/softirq.c:480) </IRQ> Fixes: 45c8a6cc2bcd ("tcp: Clear tcp_sk(sk)->fastopen_rsk in tcp_disconnect().") Reported-by: syzkaller <syzkaller@googlegroups.com> Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Link: https://patch.msgid.link/20251001233755.1340927-1-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-03net: psp: don't assume reply skbs will have a socketJakub Kicinski
Rx path may be passing around unreferenced sockets, which means that skb_set_owner_edemux() may not set skb->sk and PSP will crash: KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] RIP: 0010:psp_reply_set_decrypted (./include/net/psp/functions.h:132 net/psp/psp_sock.c:287) tcp_v6_send_response.constprop.0 (net/ipv6/tcp_ipv6.c:979) tcp_v6_send_reset (net/ipv6/tcp_ipv6.c:1140 (discriminator 1)) tcp_v6_do_rcv (net/ipv6/tcp_ipv6.c:1683) tcp_v6_rcv (net/ipv6/tcp_ipv6.c:1912) Fixes: 659a2899a57d ("tcp: add datapath logic for PSP with inline key exchange") Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20251001022426.2592750-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-02Merge tag 'net-next-6.18' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Paolo Abeni: "Core & protocols: - Improve drop account scalability on NUMA hosts for RAW and UDP sockets and the backlog, almost doubling the Pps capacity under DoS - Optimize the UDP RX performance under stress, reducing contention, revisiting the binary layout of the involved data structs and implementing NUMA-aware locking. This improves UDP RX performance by an additional 50%, even more under extreme conditions - Add support for PSP encryption of TCP connections; this mechanism has some similarities with IPsec and TLS, but offers superior HW offloads capabilities - Ongoing work to support Accurate ECN for TCP. AccECN allows more than one congestion notification signal per RTT and is a building block for Low Latency, Low Loss, and Scalable Throughput (L4S) - Reorganize the TCP socket binary layout for data locality, reducing the number of touched cachelines in the fastpath - Refactor skb deferral free to better scale on large multi-NUMA hosts, this improves TCP and UDP RX performances significantly on such HW - Increase the default socket memory buffer limits from 256K to 4M to better fit modern link speeds - Improve handling of setups with a large number of nexthop, making dump operating scaling linearly and avoiding unneeded synchronize_rcu() on delete - Improve bridge handling of VLAN FDB, storing a single entry per bridge instead of one entry per port; this makes the dump order of magnitude faster on large switches - Restore IP ID correctly for encapsulated packets at GSO segmentation time, allowing GRO to merge packets in more scenarios - Improve netfilter matching performance on large sets - Improve MPTCP receive path performance by leveraging recently introduced core infrastructure (skb deferral free) and adopting recent TCP autotuning changes - Allow bridges to redirect to a backup port when the bridge port is administratively down - Introduce MPTCP 'laminar' endpoint that con be used only once per connection and simplify common MPTCP setups - Add RCU safety to dst->dev, closing a lot of possible races - A significant crypto library API for SCTP, MPTCP and IPv6 SR, reducing code duplication - Supports pulling data from an skb frag into the linear area of an XDP buffer Things we sprinkled into general kernel code: - Generate netlink documentation from YAML using an integrated YAML parser Driver API: - Support using IPv6 Flow Label in Rx hash computation and RSS queue selection - Introduce API for fetching the DMA device for a given queue, allowing TCP zerocopy RX on more H/W setups - Make XDP helpers compatible with unreadable memory, allowing more easily building DevMem-enabled drivers with a unified XDP/skbs datapath - Add a new dedicated ethtool callback enabling drivers to provide the number of RX rings directly, improving efficiency and clarity in RX ring queries and RSS configuration - Introduce a burst period for the health reporter, allowing better handling of multiple errors due to the same root cause - Support for DPLL phase offset exponential moving average, controlling the average smoothing factor Device drivers: - Add a new Huawei driver for 3rd gen NIC (hinic3) - Add a new SpacemiT driver for K1 ethernet MAC - Add a generic abstraction for shared memory communication devices (dibps) - Ethernet high-speed NICs: - nVidia/Mellanox: - Use multiple per-queue doorbell, to avoid MMIO contention issues - support adjacent functions, allowing them to delegate their SR-IOV VFs to sibling PFs - support RSS for IPSec offload - support exposing raw cycle counters in PTP and mlx5 - support for disabling host PFs. - Intel (100G, ice, idpf): - ice: support for SRIOV VFs over an Active-Active link aggregate - ice: support for firmware logging via debugfs - ice: support for Earliest TxTime First (ETF) hardware offload - idpf: support basic XDP functionalities and XSk - Broadcom (bnxt): - support Hyper-V VF ID - dynamic SRIOV resource allocations for RoCE - Meta (fbnic): - support queue API, zero-copy Rx and Tx - support basic XDP functionalities - devlink health support for FW crashes and OTP mem corruptions - expand hardware stats coverage to FEC, PHY, and Pause - Wangxun: - support ethtool coalesce options - support for multiple RSS contexts - Ethernet virtual: - Macsec: - replace custom netlink attribute checks with policy-level checks - Bonding: - support aggregator selection based on port priority - Microsoft vNIC: - use page pool fragments for RX buffers instead of full pages to improve memory efficiency - Ethernet NICs consumer, and embedded: - Qualcomm: support Ethernet function for IPQ9574 SoC - Airoha: implement wlan offloading via NPU - Freescale - enetc: add NETC timer PTP driver and add PTP support - fec: enable the Jumbo frame support for i.MX8QM - Renesas (R-Car S4): - support HW offloading for layer 2 switching - support for RZ/{T2H, N2H} SoCs - Cadence (macb): support TAPRIO traffic scheduling - TI: - support for Gigabit ICSS ethernet SoC (icssm-prueth) - Synopsys (stmmac): a lot of cleanups - Ethernet PHYs: - Support 10g-qxgmi phy-mode for AQR412C, Felix DSA and Lynx PCS driver - Support bcm63268 GPHY power control - Support for Micrel lan8842 PHY and PTP - Support for Aquantia AQR412 and AQR115 - CAN: - a large CAN-XL preparation work - reorganize raw_sock and uniqframe struct to minimize memory usage - rcar_canfd: update the CAN-FD handling - WiFi: - extended Neighbor Awareness Networking (NAN) support - S1G channel representation cleanup - improve S1G support - WiFi drivers: - Intel (iwlwifi): - major refactor and cleanup - Broadcom (brcm80211): - support for AP isolation - RealTek (rtw88/89) rtw88/89: - preparation work for RTL8922DE support - MediaTek (mt76): - HW restart improvements - MLO support - Qualcomm/Atheros (ath10k): - GTK rekey fixes - Bluetooth drivers: - btusb: support for several new IDs for MT7925 - btintel: support for BlazarIW core - btintel_pcie: support for _suspend() / _resume() - btintel_pcie: support for Scorpious, Panther Lake-H484 IDs" * tag 'net-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1536 commits) net: stmmac: Add support for Allwinner A523 GMAC200 dt-bindings: net: sun8i-emac: Add A523 GMAC200 compatible Revert "Documentation: net: add flow control guide and document ethtool API" octeontx2-pf: fix bitmap leak octeontx2-vf: fix bitmap leak net/mlx5e: Use extack in set rxfh callback net/mlx5e: Introduce mlx5e_rss_params for RSS configuration net/mlx5e: Introduce mlx5e_rss_init_params net/mlx5e: Remove unused mdev param from RSS indir init net/mlx5: Improve QoS error messages with actual depth values net/mlx5e: Prevent entering switchdev mode with inconsistent netns net/mlx5: HWS, Generalize complex matchers net/mlx5: Improve write-combining test reliability for ARM64 Grace CPUs selftests/net: add tcp_port_share to .gitignore Revert "net/mlx5e: Update and set Xon/Xoff upon MTU set" net: add NUMA awareness to skb_attempt_defer_free() net: use llist for sd->defer_list net: make softnet_data.defer_count an atomic selftests: drv-net: psp: add tests for destroying devices selftests: drv-net: psp: add test for auto-adjusting TCP MSS ...
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>
2025-09-29tcp: use skb->len instead of skb->truesize in tcp_can_ingest()Eric Dumazet
Some applications are stuck to the 20th century and still use small SO_RCVBUF values. After the blamed commit, we can drop packets especially when using LRO/hw-gro enabled NIC and small MSS (1500) values. LRO/hw-gro NIC pack multiple segments into pages, allowing tp->scaling_ratio to be set to a high value. Whenever the receive queue gets full, we can receive a small packet filling RWIN, but with a high skb->truesize, because most NIC use 4K page plus sk_buff metadata even when receiving less than 1500 bytes of payload. Even if we refine how tp->scaling_ratio is estimated, we could have an issue at the start of the flow, because the first round of packets (IW10) will be sent based on the initial tp->scaling_ratio (1/2) Relax tcp_can_ingest() to use skb->len instead of skb->truesize, allowing the peer to use final RWIN, assuming a 'perfect' scaling_ratio of 1. Fixes: 1d2fbaad7cd8 ("tcp: stronger sk_rcvbuf checks") Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20250927092827.2707901-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-29Merge tag 'namespace-6.18-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull namespace updates from Christian Brauner: "This contains a larger set of changes around the generic namespace infrastructure of the kernel. Each specific namespace type (net, cgroup, mnt, ...) embedds a struct ns_common which carries the reference count of the namespace and so on. We open-coded and cargo-culted so many quirks for each namespace type that it just wasn't scalable anymore. So given there's a bunch of new changes coming in that area I've started cleaning all of this up. The core change is to make it possible to correctly initialize every namespace uniformly and derive the correct initialization settings from the type of the namespace such as namespace operations, namespace type and so on. This leaves the new ns_common_init() function with a single parameter which is the specific namespace type which derives the correct parameters statically. This also means the compiler will yell as soon as someone does something remotely fishy. The ns_common_init() addition also allows us to remove ns_alloc_inum() and drops any special-casing of the initial network namespace in the network namespace initialization code that Linus complained about. Another part is reworking the reference counting. The reference counting was open-coded and copy-pasted for each namespace type even though they all followed the same rules. This also removes all open accesses to the reference count and makes it private and only uses a very small set of dedicated helpers to manipulate them just like we do for e.g., files. In addition this generalizes the mount namespace iteration infrastructure introduced a few cycles ago. As reminder, the vfs makes it possible to iterate sequentially and bidirectionally through all mount namespaces on the system or all mount namespaces that the caller holds privilege over. This allow userspace to iterate over all mounts in all mount namespaces using the listmount() and statmount() system call. Each mount namespace has a unique identifier for the lifetime of the systems that is exposed to userspace. The network namespace also has a unique identifier working exactly the same way. This extends the concept to all other namespace types. The new nstree type makes it possible to lookup namespaces purely by their identifier and to walk the namespace list sequentially and bidirectionally for all namespace types, allowing userspace to iterate through all namespaces. Looking up namespaces in the namespace tree works completely locklessly. This also means we can move the mount namespace onto the generic infrastructure and remove a bunch of code and members from struct mnt_namespace itself. There's a bunch of stuff coming on top of this in the future but for now this uses the generic namespace tree to extend a concept introduced first for pidfs a few cycles ago. For a while now we have supported pidfs file handles for pidfds. This has proven to be very useful. This extends the concept to cover namespaces as well. It is possible to encode and decode namespace file handles using the common name_to_handle_at() and open_by_handle_at() apis. As with pidfs file handles, namespace file handles are exhaustive, meaning it is not required to actually hold a reference to nsfs in able to decode aka open_by_handle_at() a namespace file handle. Instead the FD_NSFS_ROOT constant can be passed which will let the kernel grab a reference to the root of nsfs internally and thus decode the file handle. Namespaces file descriptors can already be derived from pidfds which means they aren't subject to overmount protection bugs. IOW, it's irrelevant if the caller would not have access to an appropriate /proc/<pid>/ns/ directory as they could always just derive the namespace based on a pidfd already. It has the same advantage as pidfds. It's possible to reliably and for the lifetime of the system refer to a namespace without pinning any resources and to compare them trivially. Permission checking is kept simple. If the caller is located in the namespace the file handle refers to they are able to open it otherwise they must hold privilege over the owning namespace of the relevant namespace. The namespace file handle layout is exposed as uapi and has a stable and extensible format. For now it simply contains the namespace identifier, the namespace type, and the inode number. The stable format means that userspace may construct its own namespace file handles without going through name_to_handle_at() as they are already allowed for pidfs and cgroup file handles" * tag 'namespace-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (65 commits) ns: drop assert ns: move ns type into struct ns_common nstree: make struct ns_tree private ns: add ns_debug() ns: simplify ns_common_init() further cgroup: add missing ns_common include ns: use inode initializer for initial namespaces selftests/namespaces: verify initial namespace inode numbers ns: rename to __ns_ref nsfs: port to ns_ref_*() helpers net: port to ns_ref_*() helpers uts: port to ns_ref_*() helpers ipv4: use check_net() net: use check_net() net-sysfs: use check_net() user: port to ns_ref_*() helpers time: port to ns_ref_*() helpers pid: port to ns_ref_*() helpers ipc: port to ns_ref_*() helpers cgroup: port to ns_ref_*() helpers ...
2025-09-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.17-rc8). Conflicts: drivers/net/can/spi/hi311x.c 6b6968084721 ("can: hi311x: fix null pointer dereference when resuming from sleep before interface was enabled") 27ce71e1ce81 ("net: WQ_PERCPU added to alloc_workqueue users") https://lore.kernel.org/72ce7599-1b5b-464a-a5de-228ff9724701@kernel.org net/smc/smc_loopback.c drivers/dibs/dibs_loopback.c a35c04de2565 ("net/smc: fix warning in smc_rx_splice() when calling get_page()") cc21191b584c ("dibs: Move data path to dibs layer") https://lore.kernel.org/74368a5c-48ac-4f8e-a198-40ec1ed3cf5f@kernel.org Adjacent changes: drivers/net/dsa/lantiq/lantiq_gswip.c c0054b25e2f1 ("net: dsa: lantiq_gswip: move gswip_add_single_port_br() call to port_setup()") 7a1eaef0a791 ("net: dsa: lantiq_gswip: support model-specific mac_select_pcs()") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-25net: gro: remove unnecessary df checksRichard Gobert
Currently, packets with fixed IDs will be merged only if their don't-fragment bit is set. This restriction is unnecessary since packets without the don't-fragment bit will be forwarded as-is even if they were merged together. The merged packets will be segmented into their original forms before being forwarded, either by GSO or by TSO. The IDs will also remain identical unless NETIF_F_TSO_MANGLEID is set, in which case the IDs can become incrementing, which is also fine. Clean up the code by removing the unnecessary don't-fragment checks. Signed-off-by: Richard Gobert <richardbgobert@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250923085908.4687-5-richardbgobert@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-25net: gso: restore ids of outer ip headers correctlyRichard Gobert
Currently, NETIF_F_TSO_MANGLEID indicates that the inner-most ID can be mangled. Outer IDs can always be mangled. Make GSO preserve outer IDs by default, with NETIF_F_TSO_MANGLEID allowing both inner and outer IDs to be mangled. This commit also modifies a few drivers that use SKB_GSO_FIXEDID directly. Signed-off-by: Richard Gobert <richardbgobert@gmail.com> Reviewed-by: Edward Cree <ecree.xilinx@gmail.com> # for sfc Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250923085908.4687-4-richardbgobert@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-25net: gro: only merge packets with incrementing or fixed outer idsRichard Gobert
Only merge encapsulated packets if their outer IDs are either incrementing or fixed, just like for inner IDs and IDs of non-encapsulated packets. Add another ip_fixedid bit for a total of two bits: one for outer IDs (and for unencapsulated packets) and one for inner IDs. This commit preserves the current behavior of GSO where only the IDs of the inner-most headers are restored correctly. Signed-off-by: Richard Gobert <richardbgobert@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250923085908.4687-3-richardbgobert@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-09-25net: gro: remove is_ipv6 from napi_gro_cbRichard Gobert
Remove is_ipv6 from napi_gro_cb and use sk->sk_family instead. This frees up space for another ip_fixedid bit that will be added in the next commit. udp_sock_create always creates either a AF_INET or a AF_INET6 socket, so using sk->sk_family is reliable. In IPv6-FOU, cfg->ipv6_v6only is always enabled. Signed-off-by: Richard Gobert <richardbgobert@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20250923085908.4687-2-richardbgobert@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>