Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from David Miller:

 1) Allow setting bluetooth L2CAP modes via socket option, from Luiz
    Augusto von Dentz.

 2) Add GSO partial support to igc, from Sasha Neftin.

 3) Several cleanups and improvements to r8169 from Heiner Kallweit.

 4) Add IF_OPER_TESTING link state and use it when ethtool triggers a
    device self-test. From Andrew Lunn.

 5) Start moving away from custom driver versions, use the globally
    defined kernel version instead, from Leon Romanovsky.

 6) Support GRO vis gro_cells in DSA layer, from Alexander Lobakin.

 7) Allow hard IRQ deferral during NAPI, from Eric Dumazet.

 8) Add sriov and vf support to hinic, from Luo bin.

 9) Support Media Redundancy Protocol (MRP) in the bridging code, from
    Horatiu Vultur.

10) Support netmap in the nft_nat code, from Pablo Neira Ayuso.

11) Allow UDPv6 encapsulation of ESP in the ipsec code, from Sabrina
    Dubroca. Also add ipv6 support for espintcp.

12) Lots of ReST conversions of the networking documentation, from Mauro
    Carvalho Chehab.

13) Support configuration of ethtool rxnfc flows in bcmgenet driver,
    from Doug Berger.

14) Allow to dump cgroup id and filter by it in inet_diag code, from
    Dmitry Yakunin.

15) Add infrastructure to export netlink attribute policies to
    userspace, from Johannes Berg.

16) Several optimizations to sch_fq scheduler, from Eric Dumazet.

17) Fallback to the default qdisc if qdisc init fails because otherwise
    a packet scheduler init failure will make a device inoperative. From
    Jesper Dangaard Brouer.

18) Several RISCV bpf jit optimizations, from Luke Nelson.

19) Correct the return type of the ->ndo_start_xmit() method in several
    drivers, it's netdev_tx_t but many drivers were using
    'int'. From Yunjian Wang.

20) Add an ethtool interface for PHY master/slave config, from Oleksij
    Rempel.

21) Add BPF iterators, from Yonghang Song.

22) Add cable test infrastructure, including ethool interfaces, from
    Andrew Lunn. Marvell PHY driver is the first to support this
    facility.

23) Remove zero-length arrays all over, from Gustavo A. R. Silva.

24) Calculate and maintain an explicit frame size in XDP, from Jesper
    Dangaard Brouer.

25) Add CAP_BPF, from Alexei Starovoitov.

26) Support terse dumps in the packet scheduler, from Vlad Buslov.

27) Support XDP_TX bulking in dpaa2 driver, from Ioana Ciornei.

28) Add devm_register_netdev(), from Bartosz Golaszewski.

29) Minimize qdisc resets, from Cong Wang.

30) Get rid of kernel_getsockopt and kernel_setsockopt in order to
    eliminate set_fs/get_fs calls. From Christoph Hellwig.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2517 commits)
  selftests: net: ip_defrag: ignore EPERM
  net_failover: fixed rollback in net_failover_open()
  Revert "tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv"
  Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv"
  vmxnet3: allow rx flow hash ops only when rss is enabled
  hinic: add set_channels ethtool_ops support
  selftests/bpf: Add a default $(CXX) value
  tools/bpf: Don't use $(COMPILE.c)
  bpf, selftests: Use bpf_probe_read_kernel
  s390/bpf: Use bcr 0,%0 as tail call nop filler
  s390/bpf: Maintain 8-byte stack alignment
  selftests/bpf: Fix verifier test
  selftests/bpf: Fix sample_cnt shared between two threads
  bpf, selftests: Adapt cls_redirect to call csum_level helper
  bpf: Add csum_level helper for fixing up csum levels
  bpf: Fix up bpf_skb_adjust_room helper's skb csum setting
  sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf()
  crypto/chtls: IPv6 support for inline TLS
  Crypto/chcr: Fixes a coccinile check error
  Crypto/chcr: Fixes compilations warnings
  ...

1 files changed, 216 insertions, 0 deletions

diff --git a/Documentation/networking/dccp.rst b/Documentation/networking/dccp.rst
new file mode 100644
index 000000000000..dde16be04456
--- /dev/null
+++ b/Documentation/networking/dccp.rst
@@ -0,0 +1,216 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============
+DCCP protocol
+=============
+
+
+.. Contents
+   - Introduction
+   - Missing features
+   - Socket options
+   - Sysctl variables
+   - IOCTLs
+   - Other tunables
+   - Notes
+
+
+Introduction
+============
+Datagram Congestion Control Protocol (DCCP) is an unreliable, connection
+oriented protocol designed to solve issues present in UDP and TCP, particularly
+for real-time and multimedia (streaming) traffic.
+It divides into a base protocol (RFC 4340) and pluggable congestion control
+modules called CCIDs. Like pluggable TCP congestion control, at least one CCID
+needs to be enabled in order for the protocol to function properly. In the Linux
+implementation, this is the TCP-like CCID2 (RFC 4341). Additional CCIDs, such as
+the TCP-friendly CCID3 (RFC 4342), are optional.
+For a brief introduction to CCIDs and suggestions for choosing a CCID to match
+given applications, see section 10 of RFC 4340.
+
+It has a base protocol and pluggable congestion control IDs (CCIDs).
+
+DCCP is a Proposed Standard (RFC 2026), and the homepage for DCCP as a protocol
+is at http://www.ietf.org/html.charters/dccp-charter.html
+
+
+Missing features
+================
+The Linux DCCP implementation does not currently support all the features that are
+specified in RFCs 4340...42.
+
+The known bugs are at:
+
+	http://www.linuxfoundation.org/collaborate/workgroups/networking/todo#DCCP
+
+For more up-to-date versions of the DCCP implementation, please consider using
+the experimental DCCP test tree; instructions for checking this out are on:
+http://www.linuxfoundation.org/collaborate/workgroups/networking/dccp_testing#Experimental_DCCP_source_tree
+
+
+Socket options
+==============
+DCCP_SOCKOPT_QPOLICY_ID sets the dequeuing policy for outgoing packets. It takes
+a policy ID as argument and can only be set before the connection (i.e. changes
+during an established connection are not supported). Currently, two policies are
+defined: the "simple" policy (DCCPQ_POLICY_SIMPLE), which does nothing special,
+and a priority-based variant (DCCPQ_POLICY_PRIO). The latter allows to pass an
+u32 priority value as ancillary data to sendmsg(), where higher numbers indicate
+a higher packet priority (similar to SO_PRIORITY). This ancillary data needs to
+be formatted using a cmsg(3) message header filled in as follows::
+
+	cmsg->cmsg_level = SOL_DCCP;
+	cmsg->cmsg_type	 = DCCP_SCM_PRIORITY;
+	cmsg->cmsg_len	 = CMSG_LEN(sizeof(uint32_t));	/* or CMSG_LEN(4) */
+
+DCCP_SOCKOPT_QPOLICY_TXQLEN sets the maximum length of the output queue. A zero
+value is always interpreted as unbounded queue length. If different from zero,
+the interpretation of this parameter depends on the current dequeuing policy
+(see above): the "simple" policy will enforce a fixed queue size by returning
+EAGAIN, whereas the "prio" policy enforces a fixed queue length by dropping the
+lowest-priority packet first. The default value for this parameter is
+initialised from /proc/sys/net/dccp/default/tx_qlen.
+
+DCCP_SOCKOPT_SERVICE sets the service. The specification mandates use of
+service codes (RFC 4340, sec. 8.1.2); if this socket option is not set,
+the socket will fall back to 0 (which means that no meaningful service code
+is present). On active sockets this is set before connect(); specifying more
+than one code has no effect (all subsequent service codes are ignored). The
+case is different for passive sockets, where multiple service codes (up to 32)
+can be set before calling bind().
+
+DCCP_SOCKOPT_GET_CUR_MPS is read-only and retrieves the current maximum packet
+size (application payload size) in bytes, see RFC 4340, section 14.
+
+DCCP_SOCKOPT_AVAILABLE_CCIDS is also read-only and returns the list of CCIDs
+supported by the endpoint. The option value is an array of type uint8_t whose
+size is passed as option length. The minimum array size is 4 elements, the
+value returned in the optlen argument always reflects the true number of
+built-in CCIDs.
+
+DCCP_SOCKOPT_CCID is write-only and sets both the TX and RX CCIDs at the same
+time, combining the operation of the next two socket options. This option is
+preferable over the latter two, since often applications will use the same
+type of CCID for both directions; and mixed use of CCIDs is not currently well
+understood. This socket option takes as argument at least one uint8_t value, or
+an array of uint8_t values, which must match available CCIDS (see above). CCIDs
+must be registered on the socket before calling connect() or listen().
+
+DCCP_SOCKOPT_TX_CCID is read/write. It returns the current CCID (if set) or sets
+the preference list for the TX CCID, using the same format as DCCP_SOCKOPT_CCID.
+Please note that the getsockopt argument type here is ``int``, not uint8_t.
+
+DCCP_SOCKOPT_RX_CCID is analogous to DCCP_SOCKOPT_TX_CCID, but for the RX CCID.
+
+DCCP_SOCKOPT_SERVER_TIMEWAIT enables the server (listening socket) to hold
+timewait state when closing the connection (RFC 4340, 8.3). The usual case is
+that the closing server sends a CloseReq, whereupon the client holds timewait
+state. When this boolean socket option is on, the server sends a Close instead
+and will enter TIMEWAIT. This option must be set after accept() returns.
+
+DCCP_SOCKOPT_SEND_CSCOV and DCCP_SOCKOPT_RECV_CSCOV are used for setting the
+partial checksum coverage (RFC 4340, sec. 9.2). The default is that checksums
+always cover the entire packet and that only fully covered application data is
+accepted by the receiver. Hence, when using this feature on the sender, it must
+be enabled at the receiver, too with suitable choice of CsCov.
+
+DCCP_SOCKOPT_SEND_CSCOV sets the sender checksum coverage. Values in the
+	range 0..15 are acceptable. The default setting is 0 (full coverage),
+	values between 1..15 indicate partial coverage.
+
+DCCP_SOCKOPT_RECV_CSCOV is for the receiver and has a different meaning: it
+	sets a threshold, where again values 0..15 are acceptable. The default
+	of 0 means that all packets with a partial coverage will be discarded.
+	Values in the range 1..15 indicate that packets with minimally such a
+	coverage value are also acceptable. The higher the number, the more
+	restrictive this setting (see [RFC 4340, sec. 9.2.1]). Partial coverage
+	settings are inherited to the child socket after accept().
+
+The following two options apply to CCID 3 exclusively and are getsockopt()-only.
+In either case, a TFRC info struct (defined in <linux/tfrc.h>) is returned.
+
+DCCP_SOCKOPT_CCID_RX_INFO
+	Returns a ``struct tfrc_rx_info`` in optval; the buffer for optval and
+	optlen must be set to at least sizeof(struct tfrc_rx_info).
+
+DCCP_SOCKOPT_CCID_TX_INFO
+	Returns a ``struct tfrc_tx_info`` in optval; the buffer for optval and
+	optlen must be set to at least sizeof(struct tfrc_tx_info).
+
+On unidirectional connections it is useful to close the unused half-connection
+via shutdown (SHUT_WR or SHUT_RD): this will reduce per-packet processing costs.
+
+
+Sysctl variables
+================
+Several DCCP default parameters can be managed by the following sysctls
+(sysctl net.dccp.default or /proc/sys/net/dccp/default):
+
+request_retries
+	The number of active connection initiation retries (the number of
+	Requests minus one) before timing out. In addition, it also governs
+	the behaviour of the other, passive side: this variable also sets
+	the number of times DCCP repeats sending a Response when the initial
+	handshake does not progress from RESPOND to OPEN (i.e. when no Ack
+	is received after the initial Request).  This value should be greater
+	than 0, suggested is less than 10. Analogue of tcp_syn_retries.
+
+retries1
+	How often a DCCP Response is retransmitted until the listening DCCP
+	side considers its connecting peer dead. Analogue of tcp_retries1.
+
+retries2
+	The number of times a general DCCP packet is retransmitted. This has
+	importance for retransmitted acknowledgments and feature negotiation,
+	data packets are never retransmitted. Analogue of tcp_retries2.
+
+tx_ccid = 2
+	Default CCID for the sender-receiver half-connection. Depending on the
+	choice of CCID, the Send Ack Vector feature is enabled automatically.
+
+rx_ccid = 2
+	Default CCID for the receiver-sender half-connection; see tx_ccid.
+
+seq_window = 100
+	The initial sequence window (sec. 7.5.2) of the sender. This influences
+	the local ackno validity and the remote seqno validity windows (7.5.1).
+	Values in the range Wmin = 32 (RFC 4340, 7.5.2) up to 2^32-1 can be set.
+
+tx_qlen = 5
+	The size of the transmit buffer in packets. A value of 0 corresponds
+	to an unbounded transmit buffer.
+
+sync_ratelimit = 125 ms
+	The timeout between subsequent DCCP-Sync packets sent in response to
+	sequence-invalid packets on the same socket (RFC 4340, 7.5.4). The unit
+	of this parameter is milliseconds; a value of 0 disables rate-limiting.
+
+
+IOCTLS
+======
+FIONREAD
+	Works as in udp(7): returns in the ``int`` argument pointer the size of
+	the next pending datagram in bytes, or 0 when no datagram is pending.
+
+
+Other tunables
+==============
+Per-route rto_min support
+	CCID-2 supports the RTAX_RTO_MIN per-route setting for the minimum value
+	of the RTO timer. This setting can be modified via the 'rto_min' option
+	of iproute2; for example::
+
+		> ip route change 10.0.0.0/24   rto_min 250j dev wlan0
+		> ip route add    10.0.0.254/32 rto_min 800j dev wlan0
+		> ip route show dev wlan0
+
+	CCID-3 also supports the rto_min setting: it is used to define the lower
+	bound for the expiry of the nofeedback timer. This can be useful on LANs
+	with very low RTTs (e.g., loopback, Gbit ethernet).
+
+
+Notes
+=====
+DCCP does not travel through NAT successfully at present on many boxes. This is
+because the checksum covers the pseudo-header as per TCP and UDP. Linux NAT
+support for DCCP has been added.