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2020-09-24tcp: skip DSACKs with dubious sequence rangesPriyaranjan Jha
Currently, we use length of DSACKed range to compute number of delivered packets. And if sequence range in DSACK is corrupted, we can get bogus dsacked/acked count, and bogus cwnd. This patch put bounds on DSACKed range to skip update of data delivery and spurious retransmission information, if the DSACK is unlikely caused by sender's action: - DSACKed range shouldn't be greater than maximum advertised rwnd. - Total no. of DSACKed segments shouldn't be greater than total no. of retransmitted segs. Unlike spurious retransmits, network duplicates or corrupted DSACKs shouldn't be counted as delivery. Signed-off-by: Priyaranjan Jha <priyarjha@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Alexei Starovoitov says: ==================== pull-request: bpf-next 2020-09-23 The following pull-request contains BPF updates for your *net-next* tree. We've added 95 non-merge commits during the last 22 day(s) which contain a total of 124 files changed, 4211 insertions(+), 2040 deletions(-). The main changes are: 1) Full multi function support in libbpf, from Andrii. 2) Refactoring of function argument checks, from Lorenz. 3) Make bpf_tail_call compatible with functions (subprograms), from Maciej. 4) Program metadata support, from YiFei. 5) bpf iterator optimizations, from Yonghong. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller
Two minor conflicts: 1) net/ipv4/route.c, adding a new local variable while moving another local variable and removing it's initial assignment. 2) drivers/net/dsa/microchip/ksz9477.c, overlapping changes. One pretty prints the port mode differently, whilst another changes the driver to try and obtain the port mode from the port node rather than the switch node. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-21inet_diag: validate INET_DIAG_REQ_PROTOCOL attributeEric Dumazet
User space could send an invalid INET_DIAG_REQ_PROTOCOL attribute as caught by syzbot. BUG: KMSAN: uninit-value in inet_diag_lock_handler net/ipv4/inet_diag.c:55 [inline] BUG: KMSAN: uninit-value in __inet_diag_dump+0x58c/0x720 net/ipv4/inet_diag.c:1147 CPU: 0 PID: 8505 Comm: syz-executor174 Not tainted 5.9.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219 inet_diag_lock_handler net/ipv4/inet_diag.c:55 [inline] __inet_diag_dump+0x58c/0x720 net/ipv4/inet_diag.c:1147 inet_diag_dump_compat+0x2a5/0x380 net/ipv4/inet_diag.c:1254 netlink_dump+0xb73/0x1cb0 net/netlink/af_netlink.c:2246 __netlink_dump_start+0xcf2/0xea0 net/netlink/af_netlink.c:2354 netlink_dump_start include/linux/netlink.h:246 [inline] inet_diag_rcv_msg_compat+0x5da/0x6c0 net/ipv4/inet_diag.c:1288 sock_diag_rcv_msg+0x24f/0x620 net/core/sock_diag.c:256 netlink_rcv_skb+0x6d7/0x7e0 net/netlink/af_netlink.c:2470 sock_diag_rcv+0x63/0x80 net/core/sock_diag.c:275 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x11c8/0x1490 net/netlink/af_netlink.c:1330 netlink_sendmsg+0x173a/0x1840 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0xc82/0x1240 net/socket.c:2353 ___sys_sendmsg net/socket.c:2407 [inline] __sys_sendmsg+0x6d1/0x820 net/socket.c:2440 __do_sys_sendmsg net/socket.c:2449 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x441389 Code: e8 fc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 1b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff3b02ce98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441389 RDX: 0000000000000000 RSI: 0000000020001500 RDI: 0000000000000003 RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000402130 R13: 00000000004021c0 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:143 [inline] kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:126 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80 slab_alloc_node mm/slub.c:2907 [inline] __kmalloc_node_track_caller+0x9aa/0x12f0 mm/slub.c:4511 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0x35f/0xb30 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1094 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1176 [inline] netlink_sendmsg+0xdb9/0x1840 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0xc82/0x1240 net/socket.c:2353 ___sys_sendmsg net/socket.c:2407 [inline] __sys_sendmsg+0x6d1/0x820 net/socket.c:2440 __do_sys_sendmsg net/socket.c:2449 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 3f935c75eb52 ("inet_diag: support for wider protocol numbers") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Christoph Paasch <cpaasch@apple.com> Cc: Mat Martineau <mathew.j.martineau@linux.intel.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-21bpf: Allow specifying a BTF ID per argument in function protosLorenz Bauer
Function prototypes using ARG_PTR_TO_BTF_ID currently use two ways to signal which BTF IDs are acceptable. First, bpf_func_proto.btf_id is an array of IDs, one for each argument. This array is only accessed up to the highest numbered argument that uses ARG_PTR_TO_BTF_ID and may therefore be less than five arguments long. It usually points at a BTF_ID_LIST. Second, check_btf_id is a function pointer that is called by the verifier if present. It gets the actual BTF ID of the register, and the argument number we're currently checking. It turns out that the only user check_arg_btf_id ignores the argument, and is simply used to check whether the BTF ID has a struct sock_common at it's start. Replace both of these mechanisms with an explicit BTF ID for each argument in a function proto. Thanks to btf_struct_ids_match this is very flexible: check_arg_btf_id can be replaced by requiring struct sock_common. Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200921121227.255763-5-lmb@cloudflare.com
2020-09-15nexthop: Only emit a notification when nexthop is actually deletedIdo Schimmel
Currently, the in-kernel delete notification is emitted from the error path of nexthop_add() and replace_nexthop(), which can be confusing to in-kernel listeners as they are not familiar with the nexthop. Instead, only emit the notification when the nexthop is actually deleted. The following sub-cases are covered: 1. User space deletes the nexthop 2. The nexthop is deleted by the kernel due to a netdev event (e.g., nexthop device going down) 3. A group is deleted because its last nexthop is being deleted 4. The network namespace of the nexthop device is deleted Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-15nexthop: Convert to blocking notification chainIdo Schimmel
Currently, the only listener of the nexthop notification chain is the VXLAN driver. Subsequent patches will add more listeners (e.g., device drivers such as netdevsim) that need to be able to block when processing notifications. Therefore, convert the notification chain to a blocking one. This is safe as notifications are always emitted from process context. Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-15ipv4: Update exception handling for multipath routes via same deviceDavid Ahern
Kfir reported that pmtu exceptions are not created properly for deployments where multipath routes use the same device. After some digging I see 2 compounding problems: 1. ip_route_output_key_hash_rcu is updating the flowi4_oif *after* the route lookup. This is the second use case where this has been a problem (the first is related to use of vti devices with VRF). I can not find any reason for the oif to be changed after the lookup; the code goes back to the start of git. It does not seem logical so remove it. 2. fib_lookups for exceptions do not call fib_select_path to handle multipath route selection based on the hash. The end result is that the fib_lookup used to add the exception always creates it based using the first leg of the route. An example topology showing the problem: | host1 +------+ | eth0 | .209 +------+ | +------+ switch | br0 | +------+ | +---------+---------+ | host2 | host3 +------+ +------+ | eth0 | .250 | eth0 | 192.168.252.252 +------+ +------+ +-----+ +-----+ | vti | .2 | vti | 192.168.247.3 +-----+ +-----+ \ / ================================= tunnels 192.168.247.1/24 for h in host1 host2 host3; do ip netns add ${h} ip -netns ${h} link set lo up ip netns exec ${h} sysctl -wq net.ipv4.ip_forward=1 done ip netns add switch ip -netns switch li set lo up ip -netns switch link add br0 type bridge stp 0 ip -netns switch link set br0 up for n in 1 2 3; do ip -netns switch link add eth-sw type veth peer name eth-h${n} ip -netns switch li set eth-h${n} master br0 up ip -netns switch li set eth-sw netns host${n} name eth0 done ip -netns host1 addr add 192.168.252.209/24 dev eth0 ip -netns host1 link set dev eth0 up ip -netns host1 route add 192.168.247.0/24 \ nexthop via 192.168.252.250 dev eth0 nexthop via 192.168.252.252 dev eth0 ip -netns host2 addr add 192.168.252.250/24 dev eth0 ip -netns host2 link set dev eth0 up ip -netns host2 addr add 192.168.252.252/24 dev eth0 ip -netns host3 link set dev eth0 up ip netns add tunnel ip -netns tunnel li set lo up ip -netns tunnel li add br0 type bridge ip -netns tunnel li set br0 up for n in $(seq 11 20); do ip -netns tunnel addr add dev br0 192.168.247.${n}/24 done for n in 2 3 do ip -netns tunnel link add vti${n} type veth peer name eth${n} ip -netns tunnel link set eth${n} mtu 1360 master br0 up ip -netns tunnel link set vti${n} netns host${n} mtu 1360 up ip -netns host${n} addr add dev vti${n} 192.168.247.${n}/24 done ip -netns tunnel ro add default nexthop via 192.168.247.2 nexthop via 192.168.247.3 ip netns exec host1 ping -M do -s 1400 -c3 -I 192.168.252.209 192.168.247.11 ip netns exec host1 ping -M do -s 1400 -c3 -I 192.168.252.209 192.168.247.15 ip -netns host1 ro ls cache Before this patch the cache always shows exceptions against the first leg in the multipath route; 192.168.252.250 per this example. Since the hash has an initial random seed, you may need to vary the final octet more than what is listed. In my tests, using addresses between 11 and 19 usually found 1 that used both legs. With this patch, the cache will have exceptions for both legs. Fixes: 4895c771c7f0 ("ipv4: Add FIB nexthop exceptions") Reported-by: Kfir Itzhak <mastertheknife@gmail.com> Signed-off-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14tcp: schedule EPOLLOUT after a partial sendmsgSoheil Hassas Yeganeh
For EPOLLET, applications must call sendmsg until they get EAGAIN. Otherwise, there is no guarantee that EPOLLOUT is sent if there was a failure upon memory allocation. As a result on high-speed NICs, userspace observes multiple small sendmsgs after a partial sendmsg until EAGAIN, since TCP can send 1-2 TSOs in between two sendmsg syscalls: // One large partial send due to memory allocation failure. sendmsg(20MB) = 2MB // Many small sends until EAGAIN. sendmsg(18MB) = 64KB sendmsg(17.9MB) = 128KB sendmsg(17.8MB) = 64KB ... sendmsg(...) = EAGAIN // At this point, userspace can assume an EPOLLOUT. To fix this, set the SOCK_NOSPACE on all partial sendmsg scenarios to guarantee that we send EPOLLOUT after partial sendmsg. After this commit userspace can assume that it will receive an EPOLLOUT after the first partial sendmsg. This EPOLLOUT will benefit from sk_stream_write_space() logic delaying the EPOLLOUT until significant space is available in write queue. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14tcp: return EPOLLOUT from tcp_poll only when notsent_bytes is half the limitSoheil Hassas Yeganeh
If there was any event available on the TCP socket, tcp_poll() will be called to retrieve all the events. In tcp_poll(), we call sk_stream_is_writeable() which returns true as long as we are at least one byte below notsent_lowat. This will result in quite a few spurious EPLLOUT and frequent tiny sendmsg() calls as a result. Similar to sk_stream_write_space(), use __sk_stream_is_writeable with a wake value of 1, so that we set EPOLLOUT only if half the space is available for write. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14lwtunnel: only keep the available bits when setting vxlan md->gbpXin Long
As we can see from vxlan_build/parse_gbp_hdr(), when processing metadata on vxlan rx/tx path, only dont_learn/policy_applied/policy_id fields can be set to or parse from the packet for vxlan gbp option. So do the mask when set it in lwtunnel, as it does in act_tunnel_key and cls_flower. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14ipv4: Initialize flowi4_multipath_hash in data pathDavid Ahern
flowi4_multipath_hash was added by the commit referenced below for tunnels. Unfortunately, the patch did not initialize the new field for several fast path lookups that do not initialize the entire flow struct to 0. Fix those locations. Currently, flowi4_multipath_hash is random garbage and affects the hash value computed by fib_multipath_hash for multipath selection. Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash") Signed-off-by: David Ahern <dsahern@gmail.com> Cc: wenxu <wenxu@ucloud.cn> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14tcp: remove SOCK_QUEUE_SHRUNKEric Dumazet
SOCK_QUEUE_SHRUNK is currently used by TCP as a temporary state that remembers if some room has been made in the rtx queue by an incoming ACK packet. This is later used from tcp_check_space() before considering to send EPOLLOUT. Problem is: If we receive SACK packets, and no packet is removed from RTX queue, we can send fresh packets, thus moving them from write queue to rtx queue and eventually empty the write queue. This stall can happen if TCP_NOTSENT_LOWAT is used. With this fix, we no longer risk stalling sends while holes are repaired, and we can fully use socket sndbuf. This also removes a cache line dirtying for typical RPC workloads. Fixes: c9bee3b7fdec ("tcp: TCP_NOTSENT_LOWAT socket option") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-14mptcp: call tcp_cleanup_rbuf on subflowsPaolo Abeni
That is needed to let the subflows announce promptly when new space is available in the receive buffer. tcp_cleanup_rbuf() is currently a static function, drop the scope modifier and add a declaration in the TCP header. Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-10tcp: Simplify tcp_set_congestion_control() load=false caseNeal Cardwell
Simplify tcp_set_congestion_control() by removing the initialization code path for the !load case. There are only two call sites for tcp_set_congestion_control(). The EBPF call site is the only one that passes load=false; it also passes cap_net_admin=true. Because of that, the exact same behavior can be achieved by removing the special if (!load) branch of the logic. Both before and after this commit, the EBPF case will call bpf_try_module_get(), and if that succeeds then call tcp_reinit_congestion_control() or if that fails then return EBUSY. Note that this returns the logic to a structure very similar to the structure before: commit 91b5b21c7c16 ("bpf: Add support for changing congestion control") except that the CAP_NET_ADMIN status is passed in as a function argument. This clean-up was suggested by Martin KaFai Lau. Suggested-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Lawrence Brakmo <brakmo@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Kevin Yang <yyd@google.com>
2020-09-10tcp: simplify tcp_set_congestion_control(): Always reinitializeNeal Cardwell
Now that the previous patches ensure that all call sites for tcp_set_congestion_control() want to initialize congestion control, we can simplify tcp_set_congestion_control() by removing the reinit argument and the code to support it. Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Kevin Yang <yyd@google.com> Cc: Lawrence Brakmo <brakmo@fb.com>
2020-09-10tcp: Only init congestion control if not initialized alreadyNeal Cardwell
Change tcp_init_transfer() to only initialize congestion control if it has not been initialized already. With this new approach, we can arrange things so that if the EBPF code sets the congestion control by calling setsockopt(TCP_CONGESTION) then tcp_init_transfer() will not re-initialize the CC module. This is an approach that has the following beneficial properties: (1) This allows CC module customizations made by the EBPF called in tcp_init_transfer() to persist, and not be wiped out by a later call to tcp_init_congestion_control() in tcp_init_transfer(). (2) Does not flip the order of EBPF and CC init, to avoid causing bugs for existing code upstream that depends on the current order. (3) Does not cause 2 initializations for for CC in the case where the EBPF called in tcp_init_transfer() wants to set the CC to a new CC algorithm. (4) Allows follow-on simplifications to the code in net/core/filter.c and net/ipv4/tcp_cong.c, which currently both have some complexity to special-case CC initialization to avoid double CC initialization if EBPF sets the CC. Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Kevin Yang <yyd@google.com> Cc: Lawrence Brakmo <brakmo@fb.com>
2020-09-10tcp: reflect tos value received in SYN to the socketWei Wang
This commit adds a new TCP feature to reflect the tos value received in SYN, and send it out on the SYN-ACK, and eventually set the tos value of the established socket with this reflected tos value. This provides a way to set the traffic class/QoS level for all traffic in the same connection to be the same as the incoming SYN request. It could be useful in data centers to provide equivalent QoS according to the incoming request. This feature is guarded by /proc/sys/net/ipv4/tcp_reflect_tos, and is by default turned off. Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-10ip: pass tos into ip_build_and_send_pkt()Wei Wang
This commit adds tos as a new passed in parameter to ip_build_and_send_pkt() which will be used in the later commit. This is a pure restructure and does not have any functional change. Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-10tcp: record received TOS value in the request socketWei Wang
A new field is added to the request sock to record the TOS value received on the listening socket during 3WHS: When not under syn flood, it is recording the TOS value sent in SYN. When under syn flood, it is recording the TOS value sent in the ACK. This is a preparation patch in order to do TOS reflection in the later commit. Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-10ipmr: Use full VIF ID in netlink cache reportsPaul Davey
Insert the full 16 bit VIF ID into ipmr Netlink cache reports. The VIF_ID attribute has 32 bits of space so can store the full VIF ID extracted from the high and low byte fields in the igmpmsg. Signed-off-by: Paul Davey <paul.davey@alliedtelesis.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-10ipmr: Add high byte of VIF ID to igmpmsgPaul Davey
Use the unused3 byte in struct igmpmsg to hold the high 8 bits of the VIF ID. If using more than 255 IPv4 multicast interfaces it is necessary to have access to a VIF ID for cache reports that is wider than 8 bits, the VIF ID present in the igmpmsg reports sent to mroute_sk was only 8 bits wide in the igmpmsg header. Adding the high 8 bits of the 16 bit VIF ID in the unused byte allows use of more than 255 IPv4 multicast interfaces. Signed-off-by: Paul Davey <paul.davey@alliedtelesis.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-10ipmr: Add route table ID to netlink cache reportsPaul Davey
Insert the multicast route table ID as a Netlink attribute to Netlink cache report notifications. When multiple route tables are in use it is necessary to have a way to determine which route table a given cache report belongs to when receiving the cache report. Signed-off-by: Paul Davey <paul.davey@alliedtelesis.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-08ip: fix tos reflection in ack and reset packetsWei Wang
Currently, in tcp_v4_reqsk_send_ack() and tcp_v4_send_reset(), we echo the TOS value of the received packets in the response. However, we do not want to echo the lower 2 ECN bits in accordance with RFC 3168 6.1.5 robustness principles. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-08cipso: fix 'audit_secid' kernel-doc warning in cipso_ipv4.cWang Hai
Fixes the following W=1 kernel build warning(s): net/ipv4/cipso_ipv4.c:510: warning: Excess function parameter 'audit_secid' description in 'cipso_v4_doi_remove' Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Wang Hai <wanghai38@huawei.com> Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
We got slightly different patches removing a double word in a comment in net/ipv4/raw.c - picked the version from net. Simple conflict in drivers/net/ethernet/ibm/ibmvnic.c. Use cached values instead of VNIC login response buffer (following what commit 507ebe6444a4 ("ibmvnic: Fix use-after-free of VNIC login response buffer") did). Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-09-03ip: expose inet sockopts through inet_diagWei Wang
Expose all exisiting inet sockopt bits through inet_diag for debug purpose. Corresponding changes in iproute2 ss will be submitted to output all these values. Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Mahesh Bandewar <maheshb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf-next 2020-09-01 The following pull-request contains BPF updates for your *net-next* tree. There are two small conflicts when pulling, resolve as follows: 1) Merge conflict in tools/lib/bpf/libbpf.c between 88a82120282b ("libbpf: Factor out common ELF operations and improve logging") in bpf-next and 1e891e513e16 ("libbpf: Fix map index used in error message") in net-next. Resolve by taking the hunk in bpf-next: [...] scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx); data = elf_sec_data(obj, scn); if (!scn || !data) { pr_warn("elf: failed to get %s map definitions for %s\n", MAPS_ELF_SEC, obj->path); return -EINVAL; } [...] 2) Merge conflict in drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c between 9647c57b11e5 ("xsk: i40e: ice: ixgbe: mlx5: Test for dma_need_sync earlier for better performance") in bpf-next and e20f0dbf204f ("net/mlx5e: RX, Add a prefetch command for small L1_CACHE_BYTES") in net-next. Resolve the two locations by retaining net_prefetch() and taking xsk_buff_dma_sync_for_cpu() from bpf-next. Should look like: [...] xdp_set_data_meta_invalid(xdp); xsk_buff_dma_sync_for_cpu(xdp, rq->xsk_pool); net_prefetch(xdp->data); [...] We've added 133 non-merge commits during the last 14 day(s) which contain a total of 246 files changed, 13832 insertions(+), 3105 deletions(-). The main changes are: 1) Initial support for sleepable BPF programs along with bpf_copy_from_user() helper for tracing to reliably access user memory, from Alexei Starovoitov. 2) Add BPF infra for writing and parsing TCP header options, from Martin KaFai Lau. 3) bpf_d_path() helper for returning full path for given 'struct path', from Jiri Olsa. 4) AF_XDP support for shared umems between devices and queues, from Magnus Karlsson. 5) Initial prep work for full BPF-to-BPF call support in libbpf, from Andrii Nakryiko. 6) Generalize bpf_sk_storage map & add local storage for inodes, from KP Singh. 7) Implement sockmap/hash updates from BPF context, from Lorenz Bauer. 8) BPF xor verification for scalar types & add BPF link iterator, from Yonghong Song. 9) Use target's prog type for BPF_PROG_TYPE_EXT prog verification, from Udip Pant. 10) Rework BPF tracing samples to use libbpf loader, from Daniel T. Lee. 11) Fix xdpsock sample to really cycle through all buffers, from Weqaar Janjua. 12) Improve type safety for tun/veth XDP frame handling, from Maciej Żenczykowski. 13) Various smaller cleanups and improvements all over the place. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-31net: ipv4: remove unused arg exact_dif in compute_scoreMiaohe Lin
The arg exact_dif is not used anymore, remove it. inet_exact_dif_match() is no longer needed after the above is removed, so remove it too. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-31net: clean up codestyleMiaohe Lin
This is a pure codestyle cleanup patch. No functional change intended. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-31net: Use helper macro IP_MAX_MTU in __ip_append_data()Miaohe Lin
What 0xFFFF means here is actually the max mtu of a ip packet. Use help macro IP_MAX_MTU here. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-28netfilter: delete repeated wordsRandy Dunlap
Drop duplicated words in net/netfilter/ and net/ipv4/netfilter/. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2020-08-27net: Fix some commentsMiaohe Lin
Fix some comments, including wrong function name, duplicated word and so on. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-26ipv4: nexthop: Correctly update nexthop group when replacing a nexthopIdo Schimmel
Each nexthop group contains an indication if it has IPv4 nexthops ('has_v4'). Its purpose is to prevent IPv6 routes from using groups with IPv4 nexthops. However, the indication is not updated when a nexthop is replaced. This results in the kernel wrongly rejecting IPv6 routes from pointing to groups that only contain IPv6 nexthops. Example: # ip nexthop replace id 1 via 192.0.2.2 dev dummy10 # ip nexthop replace id 10 group 1 # ip nexthop replace id 1 via 2001:db8:1::2 dev dummy10 # ip route replace 2001:db8:10::/64 nhid 10 Error: IPv6 routes can not use an IPv4 nexthop. Solve this by iterating over all the nexthop groups that the replaced nexthop is a member of and potentially update their IPv4 indication according to the new set of member nexthops. Avoid wasting cycles by only performing the update in case an IPv4 nexthop is replaced by an IPv6 nexthop. Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-26ipv4: nexthop: Correctly update nexthop group when removing a nexthopIdo Schimmel
Each nexthop group contains an indication if it has IPv4 nexthops ('has_v4'). Its purpose is to prevent IPv6 routes from using groups with IPv4 nexthops. However, the indication is not updated when a nexthop is removed. This results in the kernel wrongly rejecting IPv6 routes from pointing to groups that only contain IPv6 nexthops. Example: # ip nexthop replace id 1 via 192.0.2.2 dev dummy10 # ip nexthop replace id 2 via 2001:db8:1::2 dev dummy10 # ip nexthop replace id 10 group 1/2 # ip nexthop del id 1 # ip route replace 2001:db8:10::/64 nhid 10 Error: IPv6 routes can not use an IPv4 nexthop. Solve this by updating the indication according to the new set of member nexthops. Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-26ipv4: nexthop: Remove unnecessary rtnl_dereference()Ido Schimmel
The pointer is not RCU protected, so remove the unnecessary rtnl_dereference(). This suppresses the following warning: net/ipv4/nexthop.c:1101:24: error: incompatible types in comparison expression (different address spaces): net/ipv4/nexthop.c:1101:24: struct rb_node [noderef] __rcu * net/ipv4/nexthop.c:1101:24: struct rb_node * Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-26ipv4: nexthop: Use nla_put_be32() for NHA_GATEWAYIdo Schimmel
The code correctly uses nla_get_be32() to get the payload of the attribute, but incorrectly uses nla_put_u32() to add the attribute to the payload. This results in the following warning: net/ipv4/nexthop.c:279:59: warning: incorrect type in argument 3 (different base types) net/ipv4/nexthop.c:279:59: expected unsigned int [usertype] value net/ipv4/nexthop.c:279:59: got restricted __be32 [usertype] ipv4 Suppress the warning by using nla_put_be32(). Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-26ipv4: nexthop: Reduce allocation size of 'struct nh_group'Ido Schimmel
The struct looks as follows: struct nh_group { struct nh_group *spare; /* spare group for removals */ u16 num_nh; bool mpath; bool fdb_nh; bool has_v4; struct nh_grp_entry nh_entries[]; }; But its offset within 'struct nexthop' is also taken into account to determine the allocation size. Instead, use struct_size() to allocate only the required number of bytes. Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-26ipv4: Silence suspicious RCU usage warningIdo Schimmel
fib_info_notify_update() is always called with RTNL held, but not from an RCU read-side critical section. This leads to the following warning [1] when the FIB table list is traversed with hlist_for_each_entry_rcu(), but without a proper lockdep expression. Since modification of the list is protected by RTNL, silence the warning by adding a lockdep expression which verifies RTNL is held. [1] ============================= WARNING: suspicious RCU usage 5.9.0-rc1-custom-14233-g2f26e122d62f #129 Not tainted ----------------------------- net/ipv4/fib_trie.c:2124 RCU-list traversed in non-reader section!! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by ip/834: #0: ffffffff85a3b6b0 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x49a/0xbd0 stack backtrace: CPU: 0 PID: 834 Comm: ip Not tainted 5.9.0-rc1-custom-14233-g2f26e122d62f #129 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x100/0x184 lockdep_rcu_suspicious+0x143/0x14d fib_info_notify_update+0x8d1/0xa60 __nexthop_replace_notify+0xd2/0x290 rtm_new_nexthop+0x35e2/0x5946 rtnetlink_rcv_msg+0x4f7/0xbd0 netlink_rcv_skb+0x17a/0x480 rtnetlink_rcv+0x22/0x30 netlink_unicast+0x5ae/0x890 netlink_sendmsg+0x98a/0xf40 ____sys_sendmsg+0x879/0xa00 ___sys_sendmsg+0x122/0x190 __sys_sendmsg+0x103/0x1d0 __x64_sys_sendmsg+0x7d/0xb0 do_syscall_64+0x32/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fde28c3be57 Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10 RSP: 002b:00007ffc09330028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fde28c3be57 RDX: 0000000000000000 RSI: 00007ffc09330090 RDI: 0000000000000003 RBP: 000000005f45f911 R08: 0000000000000001 R09: 00007ffc0933012c R10: 0000000000000076 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc09330290 R14: 00007ffc09330eee R15: 00005610e48ed020 Fixes: 1bff1a0c9bbd ("ipv4: Add function to send route updates") Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-25net: clean up codestyle for net/ipv4Miaohe Lin
This is a pure codestyle cleanup patch. Also add a blank line after declarations as warned by checkpatch.pl. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-25net: Remove duplicated midx check against 0Miaohe Lin
Check midx against 0 is always equal to check midx against sk_bound_dev_if when sk_bound_dev_if is known not equal to 0 in these case. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-25net: Avoid unnecessary inet_addr_type() call when addr is INADDR_ANYMiaohe Lin
We can avoid unnecessary inet_addr_type() call by check addr against INADDR_ANY first. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-25net: Set ping saddr after we successfully get the ping portMiaohe Lin
We can defer set ping saddr until we successfully get the ping port. So we can avoid clear saddr when failed. Since ping_clear_saddr() is not used anymore now, remove it. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-25net: gain ipv4 mtu when mtu is not lockedMiaohe Lin
When mtu is locked, we should not obtain ipv4 mtu as we return immediately in this case and leave acquired ipv4 mtu unused. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-24net: Use helper macro RT_TOS() in __icmp_send()Miaohe Lin
Use helper macro RT_TOS() to get tos in __icmp_send(). Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-24net: Avoid access icmp_err_convert when icmp code is ICMP_FRAG_NEEDEDMiaohe Lin
There is no need to fetch errno and fatal info from icmp_err_convert when icmp code is ICMP_FRAG_NEEDED. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-24net: ipv4: delete repeated wordsRandy Dunlap
Drop duplicate words in comments in net/ipv4/. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-24io_uring: allow tcp ancillary data for __sys_recvmsg_sock()Luke Hsiao
For TCP tx zero-copy, the kernel notifies the process of completions by queuing completion notifications on the socket error queue. This patch allows reading these notifications via recvmsg to support TCP tx zero-copy. Ancillary data was originally disallowed due to privilege escalation via io_uring's offloading of sendmsg() onto a kernel thread with kernel credentials (https://crbug.com/project-zero/1975). So, we must ensure that the socket type is one where the ancillary data types that are delivered on recvmsg are plain data (no file descriptors or values that are translated based on the identity of the calling process). This was tested by using io_uring to call recvmsg on the MSG_ERRQUEUE with tx zero-copy enabled. Before this patch, we received -EINVALID from this specific code path. After this patch, we could read tcp tx zero-copy completion notifications from the MSG_ERRQUEUE. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Arjun Roy <arjunroy@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jann Horn <jannh@google.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Luke Hsiao <lukehsiao@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-24tcp: bpf: Optionally store mac header in TCP_SAVE_SYNMartin KaFai Lau
This patch is adapted from Eric's patch in an earlier discussion [1]. The TCP_SAVE_SYN currently only stores the network header and tcp header. This patch allows it to optionally store the mac header also if the setsockopt's optval is 2. It requires one more bit for the "save_syn" bit field in tcp_sock. This patch achieves this by moving the syn_smc bit next to the is_mptcp. The syn_smc is currently used with the TCP experimental option. Since syn_smc is only used when CONFIG_SMC is enabled, this patch also puts the "IS_ENABLED(CONFIG_SMC)" around it like the is_mptcp did with "IS_ENABLED(CONFIG_MPTCP)". The mac_hdrlen is also stored in the "struct saved_syn" to allow a quick offset from the bpf prog if it chooses to start getting from the network header or the tcp header. [1]: https://lore.kernel.org/netdev/CANn89iLJNWh6bkH7DNhy_kmcAexuUCccqERqe7z2QsvPhGrYPQ@mail.gmail.com/ Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/bpf/20200820190123.2886935-1-kafai@fb.com
2020-08-24bpf: tcp: Allow bpf prog to write and parse TCP header optionMartin KaFai Lau
[ Note: The TCP changes here is mainly to implement the bpf pieces into the bpf_skops_*() functions introduced in the earlier patches. ] The earlier effort in BPF-TCP-CC allows the TCP Congestion Control algorithm to be written in BPF. It opens up opportunities to allow a faster turnaround time in testing/releasing new congestion control ideas to production environment. The same flexibility can be extended to writing TCP header option. It is not uncommon that people want to test new TCP header option to improve the TCP performance. Another use case is for data-center that has a more controlled environment and has more flexibility in putting header options for internal only use. For example, we want to test the idea in putting maximum delay ACK in TCP header option which is similar to a draft RFC proposal [1]. This patch introduces the necessary BPF API and use them in the TCP stack to allow BPF_PROG_TYPE_SOCK_OPS program to parse and write TCP header options. It currently supports most of the TCP packet except RST. Supported TCP header option: ─────────────────────────── This patch allows the bpf-prog to write any option kind. Different bpf-progs can write its own option by calling the new helper bpf_store_hdr_opt(). The helper will ensure there is no duplicated option in the header. By allowing bpf-prog to write any option kind, this gives a lot of flexibility to the bpf-prog. Different bpf-prog can write its own option kind. It could also allow the bpf-prog to support a recently standardized option on an older kernel. Sockops Callback Flags: ────────────────────── The bpf program will only be called to parse/write tcp header option if the following newly added callback flags are enabled in tp->bpf_sock_ops_cb_flags: BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG A few words on the PARSE CB flags. When the above PARSE CB flags are turned on, the bpf-prog will be called on packets received at a sk that has at least reached the ESTABLISHED state. The parsing of the SYN-SYNACK-ACK will be discussed in the "3 Way HandShake" section. The default is off for all of the above new CB flags, i.e. the bpf prog will not be called to parse or write bpf hdr option. There are details comment on these new cb flags in the UAPI bpf.h. sock_ops->skb_data and bpf_load_hdr_opt() ───────────────────────────────────────── sock_ops->skb_data and sock_ops->skb_data_end covers the whole TCP header and its options. They are read only. The new bpf_load_hdr_opt() helps to read a particular option "kind" from the skb_data. Please refer to the comment in UAPI bpf.h. It has details on what skb_data contains under different sock_ops->op. 3 Way HandShake ─────────────── The bpf-prog can learn if it is sending SYN or SYNACK by reading the sock_ops->skb_tcp_flags. * Passive side When writing SYNACK (i.e. sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB), the received SYN skb will be available to the bpf prog. The bpf prog can use the SYN skb (which may carry the header option sent from the remote bpf prog) to decide what bpf header option should be written to the outgoing SYNACK skb. The SYN packet can be obtained by getsockopt(TCP_BPF_SYN*). More on this later. Also, the bpf prog can learn if it is in syncookie mode (by checking sock_ops->args[0] == BPF_WRITE_HDR_TCP_SYNACK_COOKIE). The bpf prog can store the received SYN pkt by using the existing bpf_setsockopt(TCP_SAVE_SYN). The example in a later patch does it. [ Note that the fullsock here is a listen sk, bpf_sk_storage is not very useful here since the listen sk will be shared by many concurrent connection requests. Extending bpf_sk_storage support to request_sock will add weight to the minisock and it is not necessary better than storing the whole ~100 bytes SYN pkt. ] When the connection is established, the bpf prog will be called in the existing PASSIVE_ESTABLISHED_CB callback. At that time, the bpf prog can get the header option from the saved syn and then apply the needed operation to the newly established socket. The later patch will use the max delay ack specified in the SYN header and set the RTO of this newly established connection as an example. The received ACK (that concludes the 3WHS) will also be available to the bpf prog during PASSIVE_ESTABLISHED_CB through the sock_ops->skb_data. It could be useful in syncookie scenario. More on this later. There is an existing getsockopt "TCP_SAVED_SYN" to return the whole saved syn pkt which includes the IP[46] header and the TCP header. A few "TCP_BPF_SYN*" getsockopt has been added to allow specifying where to start getting from, e.g. starting from TCP header, or from IP[46] header. The new getsockopt(TCP_BPF_SYN*) will also know where it can get the SYN's packet from: - (a) the just received syn (available when the bpf prog is writing SYNACK) and it is the only way to get SYN during syncookie mode. or - (b) the saved syn (available in PASSIVE_ESTABLISHED_CB and also other existing CB). The bpf prog does not need to know where the SYN pkt is coming from. The getsockopt(TCP_BPF_SYN*) will hide this details. Similarly, a flags "BPF_LOAD_HDR_OPT_TCP_SYN" is also added to bpf_load_hdr_opt() to read a particular header option from the SYN packet. * Fastopen Fastopen should work the same as the regular non fastopen case. This is a test in a later patch. * Syncookie For syncookie, the later example patch asks the active side's bpf prog to resend the header options in ACK. The server can use bpf_load_hdr_opt() to look at the options in this received ACK during PASSIVE_ESTABLISHED_CB. * Active side The bpf prog will get a chance to write the bpf header option in the SYN packet during WRITE_HDR_OPT_CB. The received SYNACK pkt will also be available to the bpf prog during the existing ACTIVE_ESTABLISHED_CB callback through the sock_ops->skb_data and bpf_load_hdr_opt(). * Turn off header CB flags after 3WHS If the bpf prog does not need to write/parse header options beyond the 3WHS, the bpf prog can clear the bpf_sock_ops_cb_flags to avoid being called for header options. Or the bpf-prog can select to leave the UNKNOWN_HDR_OPT_CB_FLAG on so that the kernel will only call it when there is option that the kernel cannot handle. [1]: draft-wang-tcpm-low-latency-opt-00 https://tools.ietf.org/html/draft-wang-tcpm-low-latency-opt-00 Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200820190104.2885895-1-kafai@fb.com