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  1. 15 10月, 2021 3 次提交
  3. 19 4月, 2021 1 次提交
  5. 10 12月, 2020 1 次提交
  7. 25 11月, 2020 1 次提交
    • A
      tcp: Set ECT0 bit in tos/tclass for synack when BPF needs ECN · 407c85c7
      由 Alexander Duyck 提交于 
      When a BPF program is used to select between a type of TCP congestion
control algorithm that uses either ECN or not there is a case where the
synack for the frame was coming up without the ECT0 bit set. A bit of
research found that this was due to the final socket being configured to
dctcp while the listener socket was staying in cubic.

To reproduce it all that is needed is to monitor TCP traffic while running
the sample bpf program "samples/bpf/tcp_cong_kern.c". What is observed,
assuming tcp_dctcp module is loaded or compiled in and the traffic matches
the rules in the sample file, is that for all frames with the exception of
the synack the ECT0 bit is set.

To address that it is necessary to make one additional call to
tcp_bpf_ca_needs_ecn using the request socket and then use the output of
that to set the ECT0 bit for the tos/tclass of the packet.

Fixes: 91b5b21c ("bpf: Add support for changing congestion control")
Signed-off-by: NAlexander Duyck <alexanderduyck@fb.com>
Link: https://lore.kernel.org/r/160593039663.2604.1374502006916871573.stgit@localhost.localdomainSigned-off-by: NJakub Kicinski <kuba@kernel.org>
      407c85c7
  9. 24 11月, 2020 1 次提交
    • R
      tcp: fix race condition when creating child sockets from syncookies · 01770a16
      由 Ricardo Dias 提交于 
      When the TCP stack is in SYN flood mode, the server child socket is
created from the SYN cookie received in a TCP packet with the ACK flag
set.

The child socket is created when the server receives the first TCP
packet with a valid SYN cookie from the client. Usually, this packet
corresponds to the final step of the TCP 3-way handshake, the ACK
packet. But is also possible to receive a valid SYN cookie from the
first TCP data packet sent by the client, and thus create a child socket
from that SYN cookie.

Since a client socket is ready to send data as soon as it receives the
SYN+ACK packet from the server, the client can send the ACK packet (sent
by the TCP stack code), and the first data packet (sent by the userspace
program) almost at the same time, and thus the server will equally
receive the two TCP packets with valid SYN cookies almost at the same
instant.

When such event happens, the TCP stack code has a race condition that
occurs between the momement a lookup is done to the established
connections hashtable to check for the existence of a connection for the
same client, and the moment that the child socket is added to the
established connections hashtable. As a consequence, this race condition
can lead to a situation where we add two child sockets to the
established connections hashtable and deliver two sockets to the
userspace program to the same client.

This patch fixes the race condition by checking if an existing child
socket exists for the same client when we are adding the second child
socket to the established connections socket. If an existing child
socket exists, we drop the packet and discard the second child socket
to the same client.
Signed-off-by: NRicardo Dias <rdias@singlestore.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20201120111133.GA67501@rdias-suse-pc.lanSigned-off-by: NJakub Kicinski <kuba@kernel.org>
      01770a16
  11. 21 11月, 2020 1 次提交
    • A
      tcp: Allow full IP tos/IPv6 tclass to be reflected in L3 header · 861602b5
      由 Alexander Duyck 提交于 
      An issue was recently found where DCTCP SYN/ACK packets did not have the
ECT bit set in the L3 header. A bit of code review found that the recent
change referenced below had gone though and added a mask that prevented the
ECN bits from being populated in the L3 header.

This patch addresses that by rolling back the mask so that it is only
applied to the flags coming from the incoming TCP request instead of
applying it to the socket tos/tclass field. Doing this the ECT bits were
restored in the SYN/ACK packets in my testing.

One thing that is not addressed by this patch set is the fact that
tcp_reflect_tos appears to be incompatible with ECN based congestion
avoidance algorithms. At a minimum the feature should likely be documented
which it currently isn't.

Fixes: ac8f1710 ("tcp: reflect tos value received in SYN to the socket")
Signed-off-by: NAlexander Duyck <alexanderduyck@fb.com>
Acked-by: NWei Wang <weiwan@google.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
      861602b5
  13. 19 9月, 2020 1 次提交
  15. 11 9月, 2020 1 次提交
    • W
      tcp: reflect tos value received in SYN to the socket · ac8f1710
      由 Wei Wang 提交于 
      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: NWei Wang <weiwan@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      ac8f1710
  17. 09 9月, 2020 1 次提交
  19. 25 8月, 2020 1 次提交
    • M
      bpf: tcp: Add bpf_skops_hdr_opt_len() and bpf_skops_write_hdr_opt() · 331fca43
      由 Martin KaFai Lau 提交于 
      The bpf prog needs to parse the SYN header to learn what options have
been sent by the peer's bpf-prog before writing its options into SYNACK.
This patch adds a "syn_skb" arg to tcp_make_synack() and send_synack().
This syn_skb will eventually be made available (as read-only) to the
bpf prog.  This will be the only SYN packet available to the bpf
prog during syncookie.  For other regular cases, the bpf prog can
also use the saved_syn.

When writing options, the bpf prog will first be called to tell the
kernel its required number of bytes.  It is done by the new
bpf_skops_hdr_opt_len().  The bpf prog will only be called when the new
BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG is set in tp->bpf_sock_ops_cb_flags.
When the bpf prog returns, the kernel will know how many bytes are needed
and then update the "*remaining" arg accordingly.  4 byte alignment will
be included in the "*remaining" before this function returns.  The 4 byte
aligned number of bytes will also be stored into the opts->bpf_opt_len.
"bpf_opt_len" is a newly added member to the struct tcp_out_options.

Then the new bpf_skops_write_hdr_opt() will call the bpf prog to write the
header options.  The bpf prog is only called if it has reserved spaces
before (opts->bpf_opt_len > 0).

The bpf prog is the last one getting a chance to reserve header space
and writing the header option.

These two functions are half implemented to highlight the changes in
TCP stack.  The actual codes preparing the bpf running context and
invoking the bpf prog will be added in the later patch with other
necessary bpf pieces.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20200820190052.2885316-1-kafai@fb.com
      331fca43
  21. 25 7月, 2020 1 次提交
  23. 20 7月, 2020 1 次提交
  25. 21 6月, 2020 1 次提交
  27. 02 6月, 2020 1 次提交
  29. 29 5月, 2020 1 次提交
    • E
      tcp: ipv6: support RFC 6069 (TCP-LD) · d2924569
      由 Eric Dumazet 提交于 
      Make tcp_ld_RTO_revert() helper available to IPv6, and
implement RFC 6069 :

Quoting this RFC :

3. Connectivity Disruption Indication

   For Internet Protocol version 6 (IPv6) [RFC2460], the counterpart of
   the ICMP destination unreachable message of code 0 (net unreachable)
   and of code 1 (host unreachable) is the ICMPv6 destination
   unreachable message of code 0 (no route to destination) [RFC4443].
   As with IPv4, a router should generate an ICMPv6 destination
   unreachable message of code 0 in response to a packet that cannot be
   delivered to its destination address because it lacks a matching
   entry in its routing table.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NYuchung Cheng <ycheng@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d2924569
  31. 26 5月, 2020 1 次提交
    • E
      tcp: allow traceroute -Mtcp for unpriv users · 45af29ca
      由 Eric Dumazet 提交于 
      Unpriv users can use traceroute over plain UDP sockets, but not TCP ones.

$ traceroute -Mtcp 8.8.8.8
You do not have enough privileges to use this traceroute method.

$ traceroute -n -Mudp 8.8.8.8
traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets
 1  192.168.86.1  3.631 ms  3.512 ms  3.405 ms
 2  10.1.10.1  4.183 ms  4.125 ms  4.072 ms
 3  96.120.88.125  20.621 ms  19.462 ms  20.553 ms
 4  96.110.177.65  24.271 ms  25.351 ms  25.250 ms
 5  69.139.199.197  44.492 ms  43.075 ms  44.346 ms
 6  68.86.143.93  27.969 ms  25.184 ms  25.092 ms
 7  96.112.146.18  25.323 ms 96.112.146.22  25.583 ms 96.112.146.26  24.502 ms
 8  72.14.239.204  24.405 ms 74.125.37.224  16.326 ms  17.194 ms
 9  209.85.251.9  18.154 ms 209.85.247.55  14.449 ms 209.85.251.9  26.296 ms^C

We can easily support traceroute over TCP, by queueing an error message
into socket error queue.

Note that applications need to set IP_RECVERR/IPV6_RECVERR option to
enable this feature, and that the error message is only queued
while in SYN_SNT state.

socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3
setsockopt(3, SOL_IPV6, IPV6_RECVERR, [1], 4) = 0
setsockopt(3, SOL_SOCKET, SO_TIMESTAMP_OLD, [1], 4) = 0
setsockopt(3, SOL_IPV6, IPV6_UNICAST_HOPS, [5], 4) = 0
connect(3, {sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0),
        inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, 28) = -1 EHOSTUNREACH (No route to host)
recvmsg(3, {msg_name={sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0),
        inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0},
        msg_namelen=1024->28, msg_iov=[{iov_base="`\r\337\320\0004\6\1&\7\370\260\200\231\16\27\0\0\0\0\0\0\0\0 \2\n\5f\10\2\227"..., iov_len=1024}],
        msg_iovlen=1, msg_control=[{cmsg_len=32, cmsg_level=SOL_SOCKET, cmsg_type=SO_TIMESTAMP_OLD, cmsg_data={tv_sec=1590340680, tv_usec=272424}},
                                   {cmsg_len=60, cmsg_level=SOL_IPV6, cmsg_type=IPV6_RECVERR}],
        msg_controllen=96, msg_flags=MSG_ERRQUEUE}, MSG_ERRQUEUE) = 144

Suggested-by: Maciej Żenczykowski <maze@google.com
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Reviewed-by: NMaciej Żenczykowski <maze@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      45af29ca
  33. 13 3月, 2020 1 次提交
  35. 30 1月, 2020 1 次提交
    • G
      mptcp: Fix undefined mptcp_handle_ipv6_mapped for modular IPV6 · 31484d56
      由 Geert Uytterhoeven 提交于 
      If CONFIG_MPTCP=y, CONFIG_MPTCP_IPV6=n, and CONFIG_IPV6=m:

    ERROR: "mptcp_handle_ipv6_mapped" [net/ipv6/ipv6.ko] undefined!

This does not happen if CONFIG_MPTCP_IPV6=y, as CONFIG_MPTCP_IPV6
selects CONFIG_IPV6, and thus forces CONFIG_IPV6 builtin.

As exporting a symbol for an empty function would be a bit wasteful, fix
this by providing a dummy version of mptcp_handle_ipv6_mapped() for the
CONFIG_MPTCP_IPV6=n case.

Rename mptcp_handle_ipv6_mapped() to mptcpv6_handle_mapped(), to make it
clear this is a pure-IPV6 function, just like mptcpv6_init().

Fixes: cec37a6e ("mptcp: Handle MP_CAPABLE options for outgoing connections")
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      31484d56
  37. 24 1月, 2020 2 次提交
  39. 10 1月, 2020 1 次提交
  41. 03 1月, 2020 3 次提交
    • D
      net: Add device index to tcp_md5sig · 6b102db5
      由 David Ahern 提交于 
      Add support for userspace to specify a device index to limit the scope
of an entry via the TCP_MD5SIG_EXT setsockopt. The existing __tcpm_pad
is renamed to tcpm_ifindex and the new field is only checked if the new
TCP_MD5SIG_FLAG_IFINDEX is set in tcpm_flags. For now, the device index
must point to an L3 master device (e.g., VRF). The API and error
handling are setup to allow the constraint to be relaxed in the future
to any device index.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6b102db5
    • D
      tcp: Add l3index to tcp_md5sig_key and md5 functions · dea53bb8
      由 David Ahern 提交于 
      Add l3index to tcp_md5sig_key to represent the L3 domain of a key, and
add l3index to tcp_md5_do_add and tcp_md5_do_del to fill in the key.

With the key now based on an l3index, add the new parameter to the
lookup functions and consider the l3index when looking for a match.

The l3index comes from the skb when processing ingress packets leveraging
the helpers created for socket lookups, tcp_v4_sdif and inet_iif (and the
v6 variants). When the sdif index is set it means the packet ingressed a
device that is part of an L3 domain and inet_iif points to the VRF device.
For egress, the L3 domain is determined from the socket binding and
sk_bound_dev_if.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      dea53bb8
    • D
      ipv6/tcp: Pass dif and sdif to tcp_v6_inbound_md5_hash · d14c77e0
      由 David Ahern 提交于 
      The original ingress device index is saved to the cb space of the skb
and the cb is moved during tcp processing. Since tcp_v6_inbound_md5_hash
can be called before and after the cb move, pass dif and sdif to it so
the caller can save both prior to the cb move. Both are used by a later
patch.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d14c77e0
  43. 05 12月, 2019 1 次提交
  45. 07 11月, 2019 1 次提交
  47. 14 10月, 2019 4 次提交
    • E
      tcp: annotate tp->write_seq lockless reads · 0f317464
      由 Eric Dumazet 提交于 
      There are few places where we fetch tp->write_seq while
this field can change from IRQ or other cpu.

We need to add READ_ONCE() annotations, and also make
sure write sides use corresponding WRITE_ONCE() to avoid
store-tearing.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      0f317464
    • E
      tcp: annotate tp->copied_seq lockless reads · 7db48e98
      由 Eric Dumazet 提交于 
      There are few places where we fetch tp->copied_seq while
this field can change from IRQ or other cpu.

We need to add READ_ONCE() annotations, and also make
sure write sides use corresponding WRITE_ONCE() to avoid
store-tearing.

Note that tcp_inq_hint() was already using READ_ONCE(tp->copied_seq)
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7db48e98
    • E
      tcp: annotate tp->rcv_nxt lockless reads · dba7d9b8
      由 Eric Dumazet 提交于 
      There are few places where we fetch tp->rcv_nxt while
this field can change from IRQ or other cpu.

We need to add READ_ONCE() annotations, and also make
sure write sides use corresponding WRITE_ONCE() to avoid
store-tearing.

Note that tcp_inq_hint() was already using READ_ONCE(tp->rcv_nxt)

syzbot reported :

BUG: KCSAN: data-race in tcp_poll / tcp_queue_rcv

write to 0xffff888120425770 of 4 bytes by interrupt on cpu 0:
 tcp_rcv_nxt_update net/ipv4/tcp_input.c:3365 [inline]
 tcp_queue_rcv+0x180/0x380 net/ipv4/tcp_input.c:4638
 tcp_rcv_established+0xbf1/0xf50 net/ipv4/tcp_input.c:5616
 tcp_v4_do_rcv+0x381/0x4e0 net/ipv4/tcp_ipv4.c:1542
 tcp_v4_rcv+0x1a03/0x1bf0 net/ipv4/tcp_ipv4.c:1923
 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204
 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:442 [inline]
 ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523
 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004
 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5118
 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208
 napi_skb_finish net/core/dev.c:5671 [inline]
 napi_gro_receive+0x28f/0x330 net/core/dev.c:5704
 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061

read to 0xffff888120425770 of 4 bytes by task 7254 on cpu 1:
 tcp_stream_is_readable net/ipv4/tcp.c:480 [inline]
 tcp_poll+0x204/0x6b0 net/ipv4/tcp.c:554
 sock_poll+0xed/0x250 net/socket.c:1256
 vfs_poll include/linux/poll.h:90 [inline]
 ep_item_poll.isra.0+0x90/0x190 fs/eventpoll.c:892
 ep_send_events_proc+0x113/0x5c0 fs/eventpoll.c:1749
 ep_scan_ready_list.constprop.0+0x189/0x500 fs/eventpoll.c:704
 ep_send_events fs/eventpoll.c:1793 [inline]
 ep_poll+0xe3/0x900 fs/eventpoll.c:1930
 do_epoll_wait+0x162/0x180 fs/eventpoll.c:2294
 __do_sys_epoll_pwait fs/eventpoll.c:2325 [inline]
 __se_sys_epoll_pwait fs/eventpoll.c:2311 [inline]
 __x64_sys_epoll_pwait+0xcd/0x170 fs/eventpoll.c:2311
 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7254 Comm: syz-fuzzer Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      dba7d9b8
    • E
      tcp: add rcu protection around tp->fastopen_rsk · d983ea6f
      由 Eric Dumazet 提交于 
      Both tcp_v4_err() and tcp_v6_err() do the following operations
while they do not own the socket lock :

	fastopen = tp->fastopen_rsk;
 	snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;

The problem is that without appropriate barrier, the compiler
might reload tp->fastopen_rsk and trigger a NULL deref.

request sockets are protected by RCU, we can simply add
the missing annotations and barriers to solve the issue.

Fixes: 168a8f58 ("tcp: TCP Fast Open Server - main code path")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d983ea6f
  49. 27 9月, 2019 3 次提交
  51. 31 7月, 2019 1 次提交
  53. 12 7月, 2019 1 次提交
  55. 09 7月, 2019 1 次提交
    • W
      ipv6: elide flowlabel check if no exclusive leases exist · 59c820b2
      由 Willem de Bruijn 提交于 
      Processes can request ipv6 flowlabels with cmsg IPV6_FLOWINFO.
If not set, by default an autogenerated flowlabel is selected.

Explicit flowlabels require a control operation per label plus a
datapath check on every connection (every datagram if unconnected).
This is particularly expensive on unconnected sockets multiplexing
many flows, such as QUIC.

In the common case, where no lease is exclusive, the check can be
safely elided, as both lease request and check trivially succeed.
Indeed, autoflowlabel does the same even with exclusive leases.

Elide the check if no process has requested an exclusive lease.

fl6_sock_lookup previously returns either a reference to a lease or
NULL to denote failure. Modify to return a real error and update
all callers. On return NULL, they can use the label and will elide
the atomic_dec in fl6_sock_release.

This is an optimization. Robust applications still have to revert to
requesting leases if the fast path fails due to an exclusive lease.

Changes RFC->v1:
  - use static_key_false_deferred to rate limit jump label operations
    - call static_key_deferred_flush to stop timers on exit
  - move decrement out of RCU context
  - defer optimization also if opt data is associated with a lease
  - updated all fp6_sock_lookup callers, not just udp
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      59c820b2
  57. 02 7月, 2019 1 次提交
  59. 15 6月, 2019 1 次提交