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Diffstat (limited to '')
18 files changed, 274 insertions, 1073 deletions
diff --git a/Documentation/networking/bonding.rst b/Documentation/networking/bonding.rst index 31cfd7d674a6..ab98373535ea 100644 --- a/Documentation/networking/bonding.rst +++ b/Documentation/networking/bonding.rst @@ -196,11 +196,12 @@ ad_actor_sys_prio ad_actor_system In an AD system, this specifies the mac-address for the actor in - protocol packet exchanges (LACPDUs). The value cannot be NULL or - multicast. It is preferred to have the local-admin bit set for this - mac but driver does not enforce it. If the value is not given then - system defaults to using the masters' mac address as actors' system - address. + protocol packet exchanges (LACPDUs). The value cannot be a multicast + address. If the all-zeroes MAC is specified, bonding will internally + use the MAC of the bond itself. It is preferred to have the + local-admin bit set for this mac but driver does not enforce it. If + the value is not given then system defaults to using the masters' + mac address as actors' system address. This parameter has effect only in 802.3ad mode and is available through SysFs interface. @@ -421,6 +422,17 @@ arp_all_targets consider the slave up only when all of the arp_ip_targets are reachable +arp_missed_max + + Specifies the number of arp_interval monitor checks that must + fail in order for an interface to be marked down by the ARP monitor. + + In order to provide orderly failover semantics, backup interfaces + are permitted an extra monitor check (i.e., they must fail + arp_missed_max + 1 times before being marked down). + + The default value is 2, and the allowable range is 1 - 255. + downdelay Specifies the time, in milliseconds, to wait before disabling diff --git a/Documentation/networking/device_drivers/can/freescale/flexcan.rst b/Documentation/networking/device_drivers/can/freescale/flexcan.rst new file mode 100644 index 000000000000..4e3eec6cecd2 --- /dev/null +++ b/Documentation/networking/device_drivers/can/freescale/flexcan.rst @@ -0,0 +1,54 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +============================= +Flexcan CAN Controller driver +============================= + +Authors: Marc Kleine-Budde <mkl@pengutronix.de>, +Dario Binacchi <dario.binacchi@amarula.solutions.com> + +On/off RTR frames reception +=========================== + +For most flexcan IP cores the driver supports 2 RX modes: + +- FIFO +- mailbox + +The older flexcan cores (integrated into the i.MX25, i.MX28, i.MX35 +and i.MX53 SOCs) only receive RTR frames if the controller is +configured for RX-FIFO mode. + +The RX FIFO mode uses a hardware FIFO with a depth of 6 CAN frames, +while the mailbox mode uses a software FIFO with a depth of up to 62 +CAN frames. With the help of the bigger buffer, the mailbox mode +performs better under high system load situations. + +As reception of RTR frames is part of the CAN standard, all flexcan +cores come up in a mode where RTR reception is possible. + +With the "rx-rtr" private flag the ability to receive RTR frames can +be waived at the expense of losing the ability to receive RTR +messages. This trade off is beneficial in certain use cases. + +"rx-rtr" on + Receive RTR frames. (default) + + The CAN controller can and will receive RTR frames. + + On some IP cores the controller cannot receive RTR frames in the + more performant "RX mailbox" mode and will use "RX FIFO" mode + instead. + +"rx-rtr" off + + Waive ability to receive RTR frames. (not supported on all IP cores) + + This mode activates the "RX mailbox mode" for better performance, on + some IP cores RTR frames cannot be received anymore. + +The setting can only be changed if the interface is down:: + + ip link set dev can0 down + ethtool --set-priv-flags can0 rx-rtr {off|on} + ip link set dev can0 up diff --git a/Documentation/networking/device_drivers/can/index.rst b/Documentation/networking/device_drivers/can/index.rst new file mode 100644 index 000000000000..58b6e0ad3030 --- /dev/null +++ b/Documentation/networking/device_drivers/can/index.rst @@ -0,0 +1,20 @@ +.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) + +Controller Area Network (CAN) Device Drivers +============================================ + +Device drivers for CAN devices. + +Contents: + +.. toctree:: + :maxdepth: 2 + + freescale/flexcan + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/networking/device_drivers/ethernet/amazon/ena.rst b/Documentation/networking/device_drivers/ethernet/amazon/ena.rst index 01b2a69b0cb0..8bcb173e0353 100644 --- a/Documentation/networking/device_drivers/ethernet/amazon/ena.rst +++ b/Documentation/networking/device_drivers/ethernet/amazon/ena.rst @@ -135,7 +135,7 @@ The ENA driver supports two Queue Operation modes for Tx SQs: - **Low Latency Queue (LLQ) mode or "push-mode":** In this mode the driver pushes the transmit descriptors and the - first 128 bytes of the packet directly to the ENA device memory + first 96 bytes of the packet directly to the ENA device memory space. The rest of the packet payload is fetched by the device. For this operation mode, the driver uses a dedicated PCI device memory BAR, which is mapped with write-combine capability. diff --git a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst index d638b5a8aadd..199647729251 100644 --- a/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst +++ b/Documentation/networking/device_drivers/ethernet/freescale/dpaa2/overview.rst @@ -183,6 +183,7 @@ PHY and allows physical transmission and reception of Ethernet frames. IRQ config, enable, reset DPNI (Datapath Network Interface) +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Contains TX/RX queues, network interface configuration, and RX buffer pool configuration mechanisms. The TX/RX queues are in memory and are identified by queue number. diff --git a/Documentation/networking/device_drivers/ethernet/intel/ixgbe.rst b/Documentation/networking/device_drivers/ethernet/intel/ixgbe.rst index f1d5233e5e51..0a233b17c664 100644 --- a/Documentation/networking/device_drivers/ethernet/intel/ixgbe.rst +++ b/Documentation/networking/device_drivers/ethernet/intel/ixgbe.rst @@ -440,6 +440,22 @@ NOTE: For 82599-based network connections, if you are enabling jumbo frames in a virtual function (VF), jumbo frames must first be enabled in the physical function (PF). The VF MTU setting cannot be larger than the PF MTU. +NBASE-T Support +--------------- +The ixgbe driver supports NBASE-T on some devices. However, the advertisement +of NBASE-T speeds is suppressed by default, to accommodate broken network +switches which cannot cope with advertised NBASE-T speeds. Use the ethtool +command to enable advertising NBASE-T speeds on devices which support it:: + + ethtool -s eth? advertise 0x1800000001028 + +On Linux systems with INTERFACES(5), this can be specified as a pre-up command +in /etc/network/interfaces so that the interface is always brought up with +NBASE-T support, e.g.:: + + iface eth? inet dhcp + pre-up ethtool -s eth? advertise 0x1800000001028 || true + Generic Receive Offload, aka GRO -------------------------------- The driver supports the in-kernel software implementation of GRO. GRO has diff --git a/Documentation/networking/device_drivers/index.rst b/Documentation/networking/device_drivers/index.rst index 3a5a1d46e77e..5f5cfdb2a300 100644 --- a/Documentation/networking/device_drivers/index.rst +++ b/Documentation/networking/device_drivers/index.rst @@ -11,6 +11,7 @@ Contents: appletalk/index atm/index cable/index + can/index cellular/index ethernet/index fddi/index diff --git a/Documentation/networking/devlink/devlink-params.rst b/Documentation/networking/devlink/devlink-params.rst index 4878907e9232..4e01dc32bc08 100644 --- a/Documentation/networking/devlink/devlink-params.rst +++ b/Documentation/networking/devlink/devlink-params.rst @@ -109,14 +109,19 @@ own name. - Boolean - When enabled, the device driver will instantiate VDPA networking specific auxiliary device of the devlink device. + * - ``enable_iwarp`` + - Boolean + - Enable handling of iWARP traffic in the device. * - ``internal_err_reset`` - Boolean - When enabled, the device driver will reset the device on internal errors. * - ``max_macs`` - u32 - - Specifies the maximum number of MAC addresses per ethernet port of - this device. + - Typically macvlan, vlan net devices mac are also programmed in their + parent netdevice's Function rx filter. This parameter limit the + maximum number of unicast mac address filters to receive traffic from + per ethernet port of this device. * - ``region_snapshot_enable`` - Boolean - Enable capture of ``devlink-region`` snapshots. @@ -126,3 +131,9 @@ own name. will NACK any attempt of other host to reset the device. This parameter is useful for setups where a device is shared by different hosts, such as multi-host setup. + * - ``io_eq_size`` + - u32 + - Control the size of I/O completion EQs. + * - ``event_eq_size`` + - u32 + - Control the size of asynchronous control events EQ. diff --git a/Documentation/networking/devlink/ice.rst b/Documentation/networking/devlink/ice.rst index 59c78e9717d2..8c082b139bbd 100644 --- a/Documentation/networking/devlink/ice.rst +++ b/Documentation/networking/devlink/ice.rst @@ -26,8 +26,10 @@ The ``ice`` driver reports the following versions * - ``fw.mgmt`` - running - 2.1.7 - - 3-digit version number of the management firmware that controls the - PHY, link, etc. + - 3-digit version number of the management firmware running on the + Embedded Management Processor of the device. It controls the PHY, + link, access to device resources, etc. Intel documentation refers to + this as the EMP firmware. * - ``fw.mgmt.api`` - running - 1.5.1 @@ -119,6 +121,24 @@ preserving settings, and thus ``DEVLINK_FLASH_OVERWRITE_IDENTIFIERS`` on its own will be rejected. If no overwrite mask is provided, the firmware will be instructed to preserve all settings and identifying fields when updating. +Reload +====== + +The ``ice`` driver supports activating new firmware after a flash update +using ``DEVLINK_CMD_RELOAD`` with the ``DEVLINK_RELOAD_ACTION_FW_ACTIVATE`` +action. + +.. code:: shell + + $ devlink dev reload pci/0000:01:00.0 reload action fw_activate + +The new firmware is activated by issuing a device specific Embedded +Management Processor reset which requests the device to reset and reload the +EMP firmware image. + +The driver does not currently support reloading the driver via +``DEVLINK_RELOAD_ACTION_DRIVER_REINIT``. + Regions ======= diff --git a/Documentation/networking/devlink/mlx5.rst b/Documentation/networking/devlink/mlx5.rst index 4e4b97f7971a..29ad304e6fba 100644 --- a/Documentation/networking/devlink/mlx5.rst +++ b/Documentation/networking/devlink/mlx5.rst @@ -14,8 +14,19 @@ Parameters * - Name - Mode + - Validation * - ``enable_roce`` - driverinit + - Type: Boolean + * - ``io_eq_size`` + - driverinit + - The range is between 64 and 4096. + * - ``event_eq_size`` + - driverinit + - The range is between 64 and 4096. + * - ``max_macs`` + - driverinit + - The range is between 1 and 2^31. Only power of 2 values are supported. The ``mlx5`` driver also implements the following driver-specific parameters. diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst index 7b598c7e3912..9d98e0511249 100644 --- a/Documentation/networking/ethtool-netlink.rst +++ b/Documentation/networking/ethtool-netlink.rst @@ -849,7 +849,7 @@ Request contents: Kernel response contents: - ==================================== ====== ========================== + ==================================== ====== =========================== ``ETHTOOL_A_RINGS_HEADER`` nested reply header ``ETHTOOL_A_RINGS_RX_MAX`` u32 max size of RX ring ``ETHTOOL_A_RINGS_RX_MINI_MAX`` u32 max size of RX mini ring @@ -859,7 +859,8 @@ Kernel response contents: ``ETHTOOL_A_RINGS_RX_MINI`` u32 size of RX mini ring ``ETHTOOL_A_RINGS_RX_JUMBO`` u32 size of RX jumbo ring ``ETHTOOL_A_RINGS_TX`` u32 size of TX ring - ==================================== ====== ========================== + ``ETHTOOL_A_RINGS_RX_BUF_LEN`` u32 size of buffers on the ring + ==================================== ====== =========================== RINGS_SET @@ -869,13 +870,14 @@ Sets ring sizes like ``ETHTOOL_SRINGPARAM`` ioctl request. Request contents: - ==================================== ====== ========================== + ==================================== ====== =========================== ``ETHTOOL_A_RINGS_HEADER`` nested reply header ``ETHTOOL_A_RINGS_RX`` u32 size of RX ring ``ETHTOOL_A_RINGS_RX_MINI`` u32 size of RX mini ring ``ETHTOOL_A_RINGS_RX_JUMBO`` u32 size of RX jumbo ring ``ETHTOOL_A_RINGS_TX`` u32 size of TX ring - ==================================== ====== ========================== + ``ETHTOOL_A_RINGS_RX_BUF_LEN`` u32 size of buffers on the ring + ==================================== ====== =========================== Kernel checks that requested ring sizes do not exceed limits reported by driver. Driver may impose additional constraints and may not suspport all diff --git a/Documentation/networking/filter.rst b/Documentation/networking/filter.rst index ce2b8e8bb9ab..43cdc4d34745 100644 --- a/Documentation/networking/filter.rst +++ b/Documentation/networking/filter.rst @@ -6,6 +6,13 @@ Linux Socket Filtering aka Berkeley Packet Filter (BPF) ======================================================= +Notice +------ + +This file used to document the eBPF format and mechanisms even when not +related to socket filtering. The ../bpf/index.rst has more details +on eBPF. + Introduction ------------ @@ -617,15 +624,11 @@ format with similar underlying principles from BPF described in previous paragraphs is being used. However, the instruction set format is modelled closer to the underlying architecture to mimic native instruction sets, so that a better performance can be achieved (more details later). This new -ISA is called 'eBPF' or 'internal BPF' interchangeably. (Note: eBPF which +ISA is called eBPF. See the ../bpf/index.rst for details. (Note: eBPF which originates from [e]xtended BPF is not the same as BPF extensions! While eBPF is an ISA, BPF extensions date back to classic BPF's 'overloading' of BPF_LD | BPF_{B,H,W} | BPF_ABS instruction.) -It is designed to be JITed with one to one mapping, which can also open up -the possibility for GCC/LLVM compilers to generate optimized eBPF code through -an eBPF backend that performs almost as fast as natively compiled code. - The new instruction set was originally designed with the possible goal in mind to write programs in "restricted C" and compile into eBPF with a optional GCC/LLVM backend, so that it can just-in-time map to modern 64-bit CPUs with @@ -650,1032 +653,11 @@ Currently, the classic BPF format is being used for JITing on most sparc64, arm32, riscv64, riscv32 perform JIT compilation from eBPF instruction set. -Some core changes of the new internal format: - -- Number of registers increase from 2 to 10: - - The old format had two registers A and X, and a hidden frame pointer. The - new layout extends this to be 10 internal registers and a read-only frame - pointer. Since 64-bit CPUs are passing arguments to functions via registers - the number of args from eBPF program to in-kernel function is restricted - to 5 and one register is used to accept return value from an in-kernel - function. Natively, x86_64 passes first 6 arguments in registers, aarch64/ - sparcv9/mips64 have 7 - 8 registers for arguments; x86_64 has 6 callee saved - registers, and aarch64/sparcv9/mips64 have 11 or more callee saved registers. - - Therefore, eBPF calling convention is defined as: - - * R0 - return value from in-kernel function, and exit value for eBPF program - * R1 - R5 - arguments from eBPF program to in-kernel function - * R6 - R9 - callee saved registers that in-kernel function will preserve - * R10 - read-only frame pointer to access stack - - Thus, all eBPF registers map one to one to HW registers on x86_64, aarch64, - etc, and eBPF calling convention maps directly to ABIs used by the kernel on - 64-bit architectures. - - On 32-bit architectures JIT may map programs that use only 32-bit arithmetic - and may let more complex programs to be interpreted. - - R0 - R5 are scratch registers and eBPF program needs spill/fill them if - necessary across calls. Note that there is only one eBPF program (== one - eBPF main routine) and it cannot call other eBPF functions, it can only - call predefined in-kernel functions, though. - -- Register width increases from 32-bit to 64-bit: - - Still, the semantics of the original 32-bit ALU operations are preserved - via 32-bit subregisters. All eBPF registers are 64-bit with 32-bit lower - subregisters that zero-extend into 64-bit if they are being written to. - That behavior maps directly to x86_64 and arm64 subregister definition, but - makes other JITs more difficult. - - 32-bit architectures run 64-bit internal BPF programs via interpreter. - Their JITs may convert BPF programs that only use 32-bit subregisters into - native instruction set and let the rest being interpreted. - - Operation is 64-bit, because on 64-bit architectures, pointers are also - 64-bit wide, and we want to pass 64-bit values in/out of kernel functions, - so 32-bit eBPF registers would otherwise require to define register-pair - ABI, thus, there won't be able to use a direct eBPF register to HW register - mapping and JIT would need to do combine/split/move operations for every - register in and out of the function, which is complex, bug prone and slow. - Another reason is the use of atomic 64-bit counters. - -- Conditional jt/jf targets replaced with jt/fall-through: - - While the original design has constructs such as ``if (cond) jump_true; - else jump_false;``, they are being replaced into alternative constructs like - ``if (cond) jump_true; /* else fall-through */``. - -- Introduces bpf_call insn and register passing convention for zero overhead - calls from/to other kernel functions: - - Before an in-kernel function call, the internal BPF program needs to - place function arguments into R1 to R5 registers to satisfy calling - convention, then the interpreter will take them from registers and pass - to in-kernel function. If R1 - R5 registers are mapped to CPU registers - that are used for argument passing on given architecture, the JIT compiler - doesn't need to emit extra moves. Function arguments will be in the correct - registers and BPF_CALL instruction will be JITed as single 'call' HW - instruction. This calling convention was picked to cover common call - situations without performance penalty. - - After an in-kernel function call, R1 - R5 are reset to unreadable and R0 has - a return value of the function. Since R6 - R9 are callee saved, their state - is preserved across the call. - - For example, consider three C functions:: - - u64 f1() { return (*_f2)(1); } - u64 f2(u64 a) { return f3(a + 1, a); } - u64 f3(u64 a, u64 b) { return a - b; } - - GCC can compile f1, f3 into x86_64:: - - f1: - movl $1, %edi - movq _f2(%rip), %rax - jmp *%rax - f3: - movq %rdi, %rax - subq %rsi, %rax - ret - - Function f2 in eBPF may look like:: - - f2: - bpf_mov R2, R1 - bpf_add R1, 1 - bpf_call f3 - bpf_exit - - If f2 is JITed and the pointer stored to ``_f2``. The calls f1 -> f2 -> f3 and - returns will be seamless. Without JIT, __bpf_prog_run() interpreter needs to - be used to call into f2. - - For practical reasons all eBPF programs have only one argument 'ctx' which is - already placed into R1 (e.g. on __bpf_prog_run() startup) and the programs - can call kernel functions with up to 5 arguments. Calls with 6 or more arguments - are currently not supported, but these restrictions can be lifted if necessary - in the future. - - On 64-bit architectures all register map to HW registers one to one. For - example, x86_64 JIT compiler can map them as ... - - :: - - R0 - rax - R1 - rdi - R2 - rsi - R3 - rdx - R4 - rcx - R5 - r8 - R6 - rbx - R7 - r13 - R8 - r14 - R9 - r15 - R10 - rbp - - ... since x86_64 ABI mandates rdi, rsi, rdx, rcx, r8, r9 for argument passing - and rbx, r12 - r15 are callee saved. - - Then the following internal BPF pseudo-program:: - - bpf_mov R6, R1 /* save ctx */ - bpf_mov R2, 2 - bpf_mov R3, 3 - bpf_mov R4, 4 - bpf_mov R5, 5 - bpf_call foo - bpf_mov R7, R0 /* save foo() return value */ - bpf_mov R1, R6 /* restore ctx for next call */ - bpf_mov R2, 6 - bpf_mov R3, 7 - bpf_mov R4, 8 - bpf_mov R5, 9 - bpf_call bar - bpf_add R0, R7 - bpf_exit - - After JIT to x86_64 may look like:: - - push %rbp - mov %rsp,%rbp - sub $0x228,%rsp - mov %rbx,-0x228(%rbp) - mov %r13,-0x220(%rbp) - mov %rdi,%rbx - mov $0x2,%esi - mov $0x3,%edx - mov $0x4,%ecx - mov $0x5,%r8d - callq foo - mov %rax,%r13 - mov %rbx,%rdi - mov $0x6,%esi - mov $0x7,%edx - mov $0x8,%ecx - mov $0x9,%r8d - callq bar - add %r13,%rax - mov -0x228(%rbp),%rbx - mov -0x220(%rbp),%r13 - leaveq - retq - - Which is in this example equivalent in C to:: - - u64 bpf_filter(u64 ctx) - { - return foo(ctx, 2, 3, 4, 5) + bar(ctx, 6, 7, 8, 9); - } - - In-kernel functions foo() and bar() with prototype: u64 (*)(u64 arg1, u64 - arg2, u64 arg3, u64 arg4, u64 arg5); will receive arguments in proper - registers and place their return value into ``%rax`` which is R0 in eBPF. - Prologue and epilogue are emitted by JIT and are implicit in the - interpreter. R0-R5 are scratch registers, so eBPF program needs to preserve - them across the calls as defined by calling convention. - - For example the following program is invalid:: - - bpf_mov R1, 1 - bpf_call foo - bpf_mov R0, R1 - bpf_exit - - After the call the registers R1-R5 contain junk values and cannot be read. - An in-kernel eBPF verifier is used to validate internal BPF programs. - -Also in the new design, eBPF is limited to 4096 insns, which means that any -program will terminate quickly and will only call a fixed number of kernel -functions. Original BPF and the new format are two operand instructions, -which helps to do one-to-one mapping between eBPF insn and x86 insn during JIT. - -The input context pointer for invoking the interpreter function is generic, -its content is defined by a specific use case. For seccomp register R1 points -to seccomp_data, for converted BPF filters R1 points to a skb. - -A program, that is translated internally consists of the following elements:: - - op:16, jt:8, jf:8, k:32 ==> op:8, dst_reg:4, src_reg:4, off:16, imm:32 - -So far 87 internal BPF instructions were implemented. 8-bit 'op' opcode field -has room for new instructions. Some of them may use 16/24/32 byte encoding. New -instructions must be multiple of 8 bytes to preserve backward compatibility. - -Internal BPF is a general purpose RISC instruction set. Not every register and -every instruction are used during translation from original BPF to new format. -For example, socket filters are not using ``exclusive add`` instruction, but -tracing filters may do to maintain counters of events, for example. Register R9 -is not used by socket filters either, but more complex filters may be running -out of registers and would have to resort to spill/fill to stack. - -Internal BPF can be used as a generic assembler for last step performance -optimizations, socket filters and seccomp are using it as assembler. Tracing -filters may use it as assembler to generate code from kernel. In kernel usage -may not be bounded by security considerations, since generated internal BPF code -may be optimizing internal code path and not being exposed to the user space. -Safety of internal BPF can come from a verifier (TBD). In such use cases as -described, it may be used as safe instruction set. - -Just like the original BPF, the new format runs within a controlled environment, -is deterministic and the kernel can easily prove that. The safety of the program -can be determined in two steps: first step does depth-first-search to disallow -loops and other CFG validation; second step starts from the first insn and -descends all possible paths. It simulates execution of every insn and observes -the state change of registers and stack. - -eBPF opcode encoding --------------------- - -eBPF is reusing most of the opcode encoding from classic to simplify conversion -of classic BPF to eBPF. For arithmetic and jump instructions the 8-bit 'code' -field is divided into three parts:: - - +----------------+--------+--------------------+ - | 4 bits | 1 bit | 3 bits | - | operation code | source | instruction class | - +----------------+--------+--------------------+ - (MSB) (LSB) - -Three LSB bits store instruction class which is one of: - - =================== =============== - Classic BPF classes eBPF classes - =================== =============== - BPF_LD 0x00 BPF_LD 0x00 - BPF_LDX 0x01 BPF_LDX 0x01 - BPF_ST 0x02 BPF_ST 0x02 - BPF_STX 0x03 BPF_STX 0x03 - BPF_ALU 0x04 BPF_ALU 0x04 - BPF_JMP 0x05 BPF_JMP 0x05 - BPF_RET 0x06 BPF_JMP32 0x06 - BPF_MISC 0x07 BPF_ALU64 0x07 - =================== =============== - -When BPF_CLASS(code) == BPF_ALU or BPF_JMP, 4th bit encodes source operand ... - - :: - - BPF_K 0x00 - BPF_X 0x08 - - * in classic BPF, this means:: - - BPF_SRC(code) == BPF_X - use register X as source operand - BPF_SRC(code) == BPF_K - use 32-bit immediate as source operand - - * in eBPF, this means:: - - BPF_SRC(code) == BPF_X - use 'src_reg' register as source operand - BPF_SRC(code) == BPF_K - use 32-bit immediate as source operand - -... and four MSB bits store operation code. - -If BPF_CLASS(code) == BPF_ALU or BPF_ALU64 [ in eBPF ], BPF_OP(code) is one of:: - - BPF_ADD 0x00 - BPF_SUB 0x10 - BPF_MUL 0x20 - BPF_DIV 0x30 - BPF_OR 0x40 - BPF_AND 0x50 - BPF_LSH 0x60 - BPF_RSH 0x70 - BPF_NEG 0x80 - BPF_MOD 0x90 - BPF_XOR 0xa0 - BPF_MOV 0xb0 /* eBPF only: mov reg to reg */ - BPF_ARSH 0xc0 /* eBPF only: sign extending shift right */ - BPF_END 0xd0 /* eBPF only: endianness conversion */ - -If BPF_CLASS(code) == BPF_JMP or BPF_JMP32 [ in eBPF ], BPF_OP(code) is one of:: - - BPF_JA 0x00 /* BPF_JMP only */ - BPF_JEQ 0x10 - BPF_JGT 0x20 - BPF_JGE 0x30 - BPF_JSET 0x40 - BPF_JNE 0x50 /* eBPF only: jump != */ - BPF_JSGT 0x60 /* eBPF only: signed '>' */ - BPF_JSGE 0x70 /* eBPF only: signed '>=' */ - BPF_CALL 0x80 /* eBPF BPF_JMP only: function call */ - BPF_EXIT 0x90 /* eBPF BPF_JMP only: function return */ - BPF_JLT 0xa0 /* eBPF only: unsigned '<' */ - BPF_JLE 0xb0 /* eBPF only: unsigned '<=' */ - BPF_JSLT 0xc0 /* eBPF only: signed '<' */ - BPF_JSLE 0xd0 /* eBPF only: signed '<=' */ - -So BPF_ADD | BPF_X | BPF_ALU means 32-bit addition in both classic BPF -and eBPF. There are only two registers in classic BPF, so it means A += X. -In eBPF it means dst_reg = (u32) dst_reg + (u32) src_reg; similarly, -BPF_XOR | BPF_K | BPF_ALU means A ^= imm32 in classic BPF and analogous -src_reg = (u32) src_reg ^ (u32) imm32 in eBPF. - -Classic BPF is using BPF_MISC class to represent A = X and X = A moves. -eBPF is using BPF_MOV | BPF_X | BPF_ALU code instead. Since there are no -BPF_MISC operations in eBPF, the class 7 is used as BPF_ALU64 to mean -exactly the same operations as BPF_ALU, but with 64-bit wide operands -instead. So BPF_ADD | BPF_X | BPF_ALU64 means 64-bit addition, i.e.: -dst_reg = dst_reg + src_reg - -Classic BPF wastes the whole BPF_RET class to represent a single ``ret`` -operation. Classic BPF_RET | BPF_K means copy imm32 into return register -and perform function exit. eBPF is modeled to match CPU, so BPF_JMP | BPF_EXIT -in eBPF means function exit only. The eBPF program needs to store return -value into register R0 before doing a BPF_EXIT. Class 6 in eBPF is used as -BPF_JMP32 to mean exactly the same operations as BPF_JMP, but with 32-bit wide -operands for the comparisons instead. - -For load and store instructions the 8-bit 'code' field is divided as:: - - +--------+--------+-------------------+ - | 3 bits | 2 bits | 3 bits | - | mode | size | instruction class | - +--------+--------+-------------------+ - (MSB) (LSB) - -Size modifier is one of ... - -:: - - BPF_W 0x00 /* word */ - BPF_H 0x08 /* half word */ - BPF_B 0x10 /* byte */ - BPF_DW 0x18 /* eBPF only, double word */ - -... which encodes size of load/store operation:: - - B - 1 byte - H - 2 byte - W - 4 byte - DW - 8 byte (eBPF only) - -Mode modifier is one of:: - - BPF_IMM 0x00 /* used for 32-bit mov in classic BPF and 64-bit in eBPF */ - BPF_ABS 0x20 - BPF_IND 0x40 - BPF_MEM 0x60 - BPF_LEN 0x80 /* classic BPF only, reserved in eBPF */ - BPF_MSH 0xa0 /* classic BPF only, reserved in eBPF */ - BPF_ATOMIC 0xc0 /* eBPF only, atomic operations */ - -eBPF has two non-generic instructions: (BPF_ABS | <size> | BPF_LD) and -(BPF_IND | <size> | BPF_LD) which are used to access packet data. - -They had to be carried over from classic to have strong performance of -socket filters running in eBPF interpreter. These instructions can only -be used when interpreter context is a pointer to ``struct sk_buff`` and -have seven implicit operands. Register R6 is an implicit input that must -contain pointer to sk_buff. Register R0 is an implicit output which contains -the data fetched from the packet. Registers R1-R5 are scratch registers -and must not be used to store the data across BPF_ABS | BPF_LD or -BPF_IND | BPF_LD instructions. - -These instructions have implicit program exit condition as well. When -eBPF program is trying to access the data beyond the packet boundary, -the interpreter will abort the execution of the program. JIT compilers -therefore must preserve this property. src_reg and imm32 fields are -explicit inputs to these instructions. - -For example:: - - BPF_IND | BPF_W | BPF_LD means: - - R0 = ntohl(*(u32 *) (((struct sk_buff *) R6)->data + src_reg + imm32)) - and R1 - R5 were scratched. - -Unlike classic BPF instruction set, eBPF has generic load/store operations:: - - BPF_MEM | <size> | BPF_STX: *(size *) (dst_reg + off) = src_reg - BPF_MEM | <size> | BPF_ST: *(size *) (dst_reg + off) = imm32 - BPF_MEM | <size> | BPF_LDX: dst_reg = *(size *) (src_reg + off) - -Where size is one of: BPF_B or BPF_H or BPF_W or BPF_DW. - -It also includes atomic operations, which use the immediate field for extra -encoding:: - - .imm = BPF_ADD, .code = BPF_ATOMIC | BPF_W | BPF_STX: lock xadd *(u32 *)(dst_reg + off16) += src_reg - .imm = BPF_ADD, .code = BPF_ATOMIC | BPF_DW | BPF_STX: lock xadd *(u64 *)(dst_reg + off16) += src_reg - -The basic atomic operations supported are:: - - BPF_ADD - BPF_AND - BPF_OR - BPF_XOR - -Each having equivalent semantics with the ``BPF_ADD`` example, that is: the -memory location addresed by ``dst_reg + off`` is atomically modified, with -``src_reg`` as the other operand. If the ``BPF_FETCH`` flag is set in the -immediate, then these operations also overwrite ``src_reg`` with the -value that was in memory before it was modified. - -The more special operations are:: - - BPF_XCHG - -This atomically exchanges ``src_reg`` with the value addressed by ``dst_reg + -off``. :: - - BPF_CMPXCHG - -This atomically compares the value addressed by ``dst_reg + off`` with -``R0``. If they match it is replaced with ``src_reg``. In either case, the -value that was there before is zero-extended and loaded back to ``R0``. - -Note that 1 and 2 byte atomic operations are not supported. - -Clang can generate atomic instructions by default when ``-mcpu=v3`` is -enabled. If a lower version for ``-mcpu`` is set, the only atomic instruction -Clang can generate is ``BPF_ADD`` *without* ``BPF_FETCH``. If you need to enable -the atomics features, while keeping a lower ``-mcpu`` version, you can use -``-Xclang -target-feature -Xclang +alu32``. - -You may encounter ``BPF_XADD`` - this is a legacy name for ``BPF_ATOMIC``, -referring to the exclusive-add operation encoded when the immediate field is -zero. - -eBPF has one 16-byte instruction: ``BPF_LD | BPF_DW | BPF_IMM`` which consists -of two consecutive ``struct bpf_insn`` 8-byte blocks and interpreted as single -instruction that loads 64-bit immediate value into a dst_reg. -Classic BPF has similar instruction: ``BPF_LD | BPF_W | BPF_IMM`` which loads -32-bit immediate value into a register. - -eBPF verifier -------------- -The safety of the eBPF program is determined in two steps. - -First step does DAG check to disallow loops and other CFG validation. -In particular it will detect programs that have unreachable instructions. -(though classic BPF checker allows them) - -Second step starts from the first insn and descends all possible paths. -It simulates execution of every insn and observes the state change of -registers and stack. - -At the start of the program the register R1 contains a pointer to context -and has type PTR_TO_CTX. -If verifier sees an insn that does R2=R1, then R2 has now type -PTR_TO_CTX as well and can be used on the right hand side of expression. -If R1=PTR_TO_CTX and insn is R2=R1+R1, then R2=SCALAR_VALUE, -since addition of two valid pointers makes invalid pointer. -(In 'secure' mode verifier will reject any type of pointer arithmetic to make -sure that kernel addresses don't leak to unprivileged users) - -If register was never written to, it's not readable:: - - bpf_mov R0 = R2 - bpf_exit - -will be rejected, since R2 is unreadable at the start of the program. - -After kernel function call, R1-R5 are reset to unreadable and -R0 has a return type of the function. - -Since R6-R9 are callee saved, their state is preserved across the call. - -:: - - bpf_mov R6 = 1 - bpf_call foo - bpf_mov R0 = R6 - bpf_exit - -is a correct program. If there was R1 instead of R6, it would have -been rejected. - -load/store instructions are allowed only with registers of valid types, which -are PTR_TO_CTX, PTR_TO_MAP, PTR_TO_STACK. They are bounds and alignment checked. -For example:: - - bpf_mov R1 = 1 - bpf_mov R2 = 2 - bpf_xadd *(u32 *)(R1 + 3) += R2 - bpf_exit - -will be rejected, since R1 doesn't have a valid pointer type at the time of -execution of instruction bpf_xadd. - -At the start R1 type is PTR_TO_CTX (a pointer to generic ``struct bpf_context``) -A callback is used to customize verifier to restrict eBPF program access to only -certain fields within ctx structure with specified size and alignment. - -For example, the following insn:: - - bpf_ld R0 = *(u32 *)(R6 + 8) - -intends to load a word from address R6 + 8 and store it into R0 -If R6=PTR_TO_CTX, via is_valid_access() callback the verifier will know -that offset 8 of size 4 bytes can be accessed for reading, otherwise -the verifier will reject the program. -If R6=PTR_TO_STACK, then access should be aligned and be within -stack bounds, which are [-MAX_BPF_STACK, 0). In this example offset is 8, -so it will fail verification, since it's out of bounds. - -The verifier will allow eBPF program to read data from stack only after -it wrote into it. - -Classic BPF verifier does similar check with M[0-15] memory slots. -For example:: - - bpf_ld R0 = *(u32 *)(R10 - 4) - bpf_exit - -is invalid program. -Though R10 is correct read-only register and has type PTR_TO_STACK -and R10 - 4 is within stack bounds, there were no stores into that location. - -Pointer register spill/fill is tracked as well, since four (R6-R9) -callee saved registers may not be enough for some programs. - -Allowed function calls are customized with bpf_verifier_ops->get_func_proto() -The eBPF verifier will check that registers match argument constraints. -After the call register R0 will be set to return type of the function. - -Function calls is a main mechanism to extend functionality of eBPF programs. -Socket filters may let programs to call one set of functions, whereas tracing -filters may allow completely different set. - -If a function made accessible to eBPF program, it needs to be thought through -from safety point of view. The verifier will guarantee that the function is -called with valid arguments. - -seccomp vs socket filters have different security restrictions for classic BPF. -Seccomp solves this by two stage verifier: classic BPF verifier is followed -by seccomp verifier. In case of eBPF one configurable verifier is shared for -all use cases. - -See details of eBPF verifier in kernel/bpf/verifier.c - -Register value tracking ------------------------ -In order to determine the safety of an eBPF program, the verifier must track -the range of possible values in each register and also in each stack slot. -This is done with ``struct bpf_reg_state``, defined in include/linux/ -bpf_verifier.h, which unifies tracking of scalar and pointer values. Each -register state has a type, which is either NOT_INIT (the register has not been -written to), SCALAR_VALUE (some value which is not usable as a pointer), or a -pointer type. The types of pointers describe their base, as follows: - - - PTR_TO_CTX - Pointer to bpf_context. - CONST_PTR_TO_MAP - Pointer to struct bpf_map. "Const" because arithmetic - on these pointers is forbidden. - PTR_TO_MAP_VALUE - Pointer to the value stored in a map element. - PTR_TO_MAP_VALUE_OR_NULL - Either a pointer to a map value, or NULL; map accesses - (see section 'eBPF maps', below) return this type, - which becomes a PTR_TO_MAP_VALUE when checked != NULL. - Arithmetic on these pointers is forbidden. - PTR_TO_STACK - Frame pointer. - PTR_TO_PACKET - skb->data. - PTR_TO_PACKET_END - skb->data + headlen; arithmetic forbidden. - PTR_TO_SOCKET - Pointer to struct bpf_sock_ops, implicitly refcounted. - PTR_TO_SOCKET_OR_NULL - Either a pointer to a socket, or NULL; socket lookup - returns this type, which becomes a PTR_TO_SOCKET when - checked != NULL. PTR_TO_SOCKET is reference-counted, - so programs must release the reference through the - socket release function before the end of the program. - Arithmetic on these pointers is forbidden. - -However, a pointer may be offset from this base (as a result of pointer -arithmetic), and this is tracked in two parts: the 'fixed offset' and 'variable -offset'. The former is used when an exactly-known value (e.g. an immediate -operand) is added to a pointer, while the latter is used for values which are -not exactly known. The variable offset is also used in SCALAR_VALUEs, to track -the range of possible values in the register. - -The verifier's knowledge about the variable offset consists of: - -* minimum and maximum values as unsigned -* minimum and maximum values as signed - -* knowledge of the values of individual bits, in the form of a 'tnum': a u64 - 'mask' and a u64 'value'. 1s in the mask represent bits whose value is unknown; - 1s in the value represent bits known to be 1. Bits known to be 0 have 0 in both - mask and value; no bit should ever be 1 in both. For example, if a byte is read - into a register from memory, the register's top 56 bits are known zero, while - the low 8 are unknown - which is represented as the tnum (0x0; 0xff). If we - then OR this with 0x40, we get (0x40; 0xbf), then if we add 1 we get (0x0; - 0x1ff), because of potential carries. - -Besides arithmetic, the register state can also be updated by conditional -branches. For instance, if a SCALAR_VALUE is compared > 8, in the 'true' branch -it will have a umin_value (unsigned minimum value) of 9, whereas in the 'false' -branch it will have a umax_value of 8. A signed compare (with BPF_JSGT or -BPF_JSGE) would instead update the signed minimum/maximum values. Information -from the signed and unsigned bounds can be combined; for instance if a value is -first tested < 8 and then tested s> 4, the verifier will conclude that the value -is also > 4 and s< 8, since the bounds prevent crossing the sign boundary. - -PTR_TO_PACKETs with a variable offset part have an 'id', which is common to all -pointers sharing that same variable offset. This is important for packet range -checks: after adding a variable to a packet pointer register A, if you then copy -it to another register B and then add a constant 4 to A, both registers will -share the same 'id' but the A will have a fixed offset of +4. Then if A is -bounds-checked and found to be less than a PTR_TO_PACKET_END, the register B is -now known to have a safe range of at least 4 bytes. See 'Direct packet access', -below, for more on PTR_TO_PACKET ranges. - -The 'id' field is also used on PTR_TO_MAP_VALUE_OR_NULL, common to all copies of -the pointer returned from a map lookup. This means that when one copy is -checked and found to be non-NULL, all copies can become PTR_TO_MAP_VALUEs. -As well as range-checking, the tracked information is also used for enforcing -alignment of pointer accesses. For instance, on most systems the packet pointer -is 2 bytes after a 4-byte alignment. If a program adds 14 bytes to that to jump -over the Ethernet header, then reads IHL and addes (IHL * 4), the resulting -pointer will have a variable offset known to be 4n+2 for some n, so adding the 2 -bytes (NET_IP_ALIGN) gives a 4-byte alignment and so word-sized accesses through -that pointer are safe. -The 'id' field is also used on PTR_TO_SOCKET and PTR_TO_SOCKET_OR_NULL, common -to all copies of the pointer returned from a socket lookup. This has similar -behaviour to the handling for PTR_TO_MAP_VALUE_OR_NULL->PTR_TO_MAP_VALUE, but -it also handles reference tracking for the pointer. PTR_TO_SOCKET implicitly -represents a reference to the corresponding ``struct sock``. To ensure that the -reference is not leaked, it is imperative to NULL-check the reference and in -the non-NULL case, and pass the valid reference to the socket release function. - -Direct packet access --------------------- -In cls_bpf and act_bpf programs the verifier allows direct access to the packet -data via skb->data and skb->data_end pointers. -Ex:: - - 1: r4 = *(u32 *)(r1 +80) /* load skb->data_end */ - 2: r3 = *(u32 *)(r1 +76) /* load skb->data */ - 3: r5 = r3 - 4: r5 += 14 - 5: if r5 > r4 goto pc+16 - R1=ctx R3=pkt(id=0,off=0,r=14) R4=pkt_end R5=pkt(id=0,off=14,r=14) R10=fp - 6: r0 = *(u16 *)(r3 +12) /* access 12 and 13 bytes of the packet */ - -this 2byte load from the packet is safe to do, since the program author -did check ``if (skb->data + 14 > skb->data_end) goto err`` at insn #5 which -means that in the fall-through case the register R3 (which points to skb->data) -has at least 14 directly accessible bytes. The verifier marks it -as R3=pkt(id=0,off=0,r=14). -id=0 means that no additional variables were added to the register. -off=0 means that no additional constants were added. -r=14 is the range of safe access which means that bytes [R3, R3 + 14) are ok. -Note that R5 is marked as R5=pkt(id=0,off=14,r=14). It also points -to the packet data, but constant 14 was added to the register, so -it now points to ``skb->data + 14`` and accessible range is [R5, R5 + 14 - 14) -which is zero bytes. - -More complex packet access may look like:: - - - R0=inv1 R1=ctx R3=pkt(id=0,off=0,r=14) R4=pkt_end R5=pkt(id=0,off=14,r=14) R10=fp - 6: r0 = *(u8 *)(r3 +7) /* load 7th byte from the packet */ - 7: r4 = *(u8 *)(r3 +12) - 8: r4 *= 14 - 9: r3 = *(u32 *)(r1 +76) /* load skb->data */ - 10: r3 += r4 - 11: r2 = r1 - 12: r2 <<= 48 - 13: r2 >>= 48 - 14: r3 += r2 - 15: r2 = r3 - 16: r2 += 8 - 17: r1 = *(u32 *)(r1 +80) /* load skb->data_end */ - 18: if r2 > r1 goto pc+2 - R0=inv(id=0,umax_value=255,var_off=(0x0; 0xff)) R1=pkt_end R2=pkt(id=2,off=8,r=8) R3=pkt(id=2,off=0,r=8) R4=inv(id=0,umax_value=3570,var_off=(0x0; 0xfffe)) R5=pkt(id=0,off=14,r=14) R10=fp - 19: r1 = *(u8 *)(r3 +4) - -The state of the register R3 is R3=pkt(id=2,off=0,r=8) -id=2 means that two ``r3 += rX`` instructions were seen, so r3 points to some -offset within a packet and since the program author did -``if (r3 + 8 > r1) goto err`` at insn #18, the safe range is [R3, R3 + 8). -The verifier only allows 'add'/'sub' operations on packet registers. Any other -operation will set the register state to 'SCALAR_VALUE' and it won't be -available for direct packet access. - -Operation ``r3 += rX`` may overflow and become less than original skb->data, -therefore the verifier has to prevent that. So when it sees ``r3 += rX`` -instruction and rX is more than 16-bit value, any subsequent bounds-check of r3 -against skb->data_end will not give us 'range' information, so attempts to read -through the pointer will give "invalid access to packet" error. - -Ex. after insn ``r4 = *(u8 *)(r3 +12)`` (insn #7 above) the state of r4 is -R4=inv(id=0,umax_value=255,var_off=(0x0; 0xff)) which means that upper 56 bits -of the register are guaranteed to be zero, and nothing is known about the lower -8 bits. After insn ``r4 *= 14`` the state becomes -R4=inv(id=0,umax_value=3570,var_off=(0x0; 0xfffe)), since multiplying an 8-bit -value by constant 14 will keep upper 52 bits as zero, also the least significant -bit will be zero as 14 is even. Similarly ``r2 >>= 48`` will make -R2=inv(id=0,umax_value=65535,var_off=(0x0; 0xffff)), since the shift is not sign -extending. This logic is implemented in adjust_reg_min_max_vals() function, -which calls adjust_ptr_min_max_vals() for adding pointer to scalar (or vice -versa) and adjust_scalar_min_max_vals() for operations on two scalars. - -The end result is that bpf program author can access packet directly -using normal C code as:: - - void *data = (void *)(long)skb->data; - void *data_end = (void *)(long)skb->data_end; - struct eth_hdr *eth = data; - struct iphdr *iph = data + sizeof(*eth); - struct udphdr *udp = data + sizeof(*eth) + sizeof(*iph); - - if (data + sizeof(*eth) + sizeof(*iph) + sizeof(*udp) > data_end) - return 0; - if (eth->h_proto != htons(ETH_P_IP)) - return 0; - if (iph->protocol != IPPROTO_UDP || iph->ihl != 5) - return 0; - if (udp->dest == 53 || udp->source == 9) - ...; - -which makes such programs easier to write comparing to LD_ABS insn -and significantly faster. - -eBPF maps ---------- -'maps' is a generic storage of different types for sharing data between kernel -and userspace. - -The maps are accessed from user space via BPF syscall, which has commands: - -- create a map with given type and attributes - ``map_fd = bpf(BPF_MAP_CREATE, union bpf_attr *attr, u32 size)`` - using attr->map_type, attr->key_size, attr->value_size, attr->max_entries - returns process-local file descriptor or negative error - -- lookup key in a given map - ``err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)`` - using attr->map_fd, attr->key, attr->value - returns zero and stores found elem into value or negative error - -- create or update key/value pair in a given map - ``err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)`` - using attr->map_fd, attr->key, attr->value - returns zero or negative error - -- find and delete element by key in a given map - ``err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)`` - using attr->map_fd, attr->key - -- to delete map: close(fd) - Exiting process will delete maps automatically - -userspace programs use this syscall to create/access maps that eBPF programs -are concurrently updating. - -maps can have different types: hash, array, bloom filter, radix-tree, etc. - -The map is defined by: - - - type - - max number of elements - - key size in bytes - - value size in bytes - -Pruning -------- -The verifier does not actually walk all possible paths through the program. For -each new branch to analyse, the verifier looks at all the states it's previously -been in when at this instruction. If any of them contain the current state as a -subset, the branch is 'pruned' - that is, the fact that the previous state was -accepted implies the current state would be as well. For instance, if in the -previous state, r1 held a packet-pointer, and in the current state, r1 holds a -packet-pointer with a range as long or longer and at least as strict an -alignment, then r1 is safe. Similarly, if r2 was NOT_INIT before then it can't -have been used by any path from that point, so any value in r2 (including -another NOT_INIT) is safe. The implementation is in the function regsafe(). -Pruning considers not only the registers but also the stack (and any spilled -registers it may hold). They must all be safe for the branch to be pruned. -This is implemented in states_equal(). - -Understanding eBPF verifier messages ------------------------------------- - -The following are few examples of invalid eBPF programs and verifier error -messages as seen in the log: - -Program with unreachable instructions:: - - static struct bpf_insn prog[] = { - BPF_EXIT_INSN(), - BPF_EXIT_INSN(), - }; - -Error: - - unreachable insn 1 - -Program that reads uninitialized register:: - - BPF_MOV64_REG(BPF_REG_0, BPF_REG_2), - BPF_EXIT_INSN(), - -Error:: - - 0: (bf) r0 = r2 - R2 !read_ok - -Program that doesn't initialize R0 before exiting:: - - BPF_MOV64_REG(BPF_REG_2, BPF_REG_1), - BPF_EXIT_INSN(), - -Error:: - - 0: (bf) r2 = r1 - 1: (95) exit - R0 !read_ok - -Program that accesses stack out of bounds:: - - BPF_ST_MEM(BPF_DW, BPF_REG_10, 8, 0), - BPF_EXIT_INSN(), - -Error:: - - 0: (7a) *(u64 *)(r10 +8) = 0 - invalid stack off=8 size=8 - -Program that doesn't initialize stack before passing its address into function:: - - BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), - BPF_LD_MAP_FD(BPF_REG_1, 0), - BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), - BPF_EXIT_INSN(), - -Error:: - - 0: (bf) r2 = r10 - 1: (07) r2 += -8 - 2: (b7) r1 = 0x0 - 3: (85) call 1 - invalid indirect read from stack off -8+0 size 8 - -Program that uses invalid map_fd=0 while calling to map_lookup_elem() function:: - - BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), - BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), - BPF_LD_MAP_FD(BPF_REG_1, 0), - BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), - BPF_EXIT_INSN(), - -Error:: - - 0: (7a) *(u64 *)(r10 -8) = 0 - 1: (bf) r2 = r10 - 2: (07) r2 += -8 - 3: (b7) r1 = 0x0 - 4: (85) call 1 - fd 0 is not pointing to valid bpf_map - -Program that doesn't check return value of map_lookup_elem() before accessing -map element:: - - BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), - BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), - BPF_LD_MAP_FD(BPF_REG_1, 0), - BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), - BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0), - BPF_EXIT_INSN(), - -Error:: - - 0: (7a) *(u64 *)(r10 -8) = 0 - 1: (bf) r2 = r10 - 2: (07) r2 += -8 - 3: (b7) r1 = 0x0 - 4: (85) call 1 - 5: (7a) *(u64 *)(r0 +0) = 0 - R0 invalid mem access 'map_value_or_null' - -Program that correctly checks map_lookup_elem() returned value for NULL, but -accesses the memory with incorrect alignment:: - - BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), - BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), - BPF_LD_MAP_FD(BPF_REG_1, 0), - BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), - BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1), - BPF_ST_MEM(BPF_DW, BPF_REG_0, 4, 0), - BPF_EXIT_INSN(), - -Error:: - - 0: (7a) *(u64 *)(r10 -8) = 0 - 1: (bf) r2 = r10 - 2: (07) r2 += -8 - 3: (b7) r1 = 1 - 4: (85) call 1 - 5: (15) if r0 == 0x0 goto pc+1 - R0=map_ptr R10=fp - 6: (7a) *(u64 *)(r0 +4) = 0 - misaligned access off 4 size 8 - -Program that correctly checks map_lookup_elem() returned value for NULL and -accesses memory with correct alignment in one side of 'if' branch, but fails -to do so in the other side of 'if' branch:: - - BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), - BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), - BPF_LD_MAP_FD(BPF_REG_1, 0), - BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), - BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), - BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 0), - BPF_EXIT_INSN(), - BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, 1), - BPF_EXIT_INSN(), - -Error:: - - 0: (7a) *(u64 *)(r10 -8) = 0 - 1: (bf) r2 = r10 - 2: (07) r2 += -8 - 3: (b7) r1 = 1 - 4: (85) call 1 - 5: (15) if r0 == 0x0 goto pc+2 - R0=map_ptr R10=fp - 6: (7a) *(u64 *)(r0 +0) = 0 - 7: (95) exit - - from 5 to 8: R0=imm0 R10=fp - 8: (7a) *(u64 *)(r0 +0) = 1 - R0 invalid mem access 'imm' - -Program that performs a socket lookup then sets the pointer to NULL without -checking it:: - - BPF_MOV64_IMM(BPF_REG_2, 0), - BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_2, -8), - BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), - BPF_MOV64_IMM(BPF_REG_3, 4), - BPF_MOV64_IMM(BPF_REG_4, 0), - BPF_MOV64_IMM(BPF_REG_5, 0), - BPF_EMIT_CALL(BPF_FUNC_sk_lookup_tcp), - BPF_MOV64_IMM(BPF_REG_0, 0), - BPF_EXIT_INSN(), - -Error:: - - 0: (b7) r2 = 0 - 1: (63) *(u32 *)(r10 -8) = r2 - 2: (bf) r2 = r10 - 3: (07) r2 += -8 - 4: (b7) r3 = 4 - 5: (b7) r4 = 0 - 6: (b7) r5 = 0 - 7: (85) call bpf_sk_lookup_tcp#65 - 8: (b7) r0 = 0 - 9: (95) exit - Unreleased reference id=1, alloc_insn=7 - -Program that performs a socket lookup but does not NULL-check the returned -value:: - - BPF_MOV64_IMM(BPF_REG_2, 0), - BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_2, -8), - BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), - BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), - BPF_MOV64_IMM(BPF_REG_3, 4), - BPF_MOV64_IMM(BPF_REG_4, 0), - BPF_MOV64_IMM(BPF_REG_5, 0), - BPF_EMIT_CALL(BPF_FUNC_sk_lookup_tcp), - BPF_EXIT_INSN(), - -Error:: - - 0: (b7) r2 = 0 - 1: (63) *(u32 *)(r10 -8) = r2 - 2: (bf) r2 = r10 - 3: (07) r2 += -8 - 4: (b7) r3 = 4 - 5: (b7) r4 = 0 - 6: (b7) r5 = 0 - 7: (85) call bpf_sk_lookup_tcp#65 - 8: (95) exit - Unreleased reference id=1, alloc_insn=7 - Testing ------- Next to the BPF toolchain, the kernel also ships a test module that contains -various test cases for classic and internal BPF that can be executed against +various test cases for classic and eBPF that can be executed against the BPF interpreter and JIT compiler. It can be found in lib/test_bpf.c and enabled via Kconfig:: diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index c04431144f7a..2572eecc3e86 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -25,7 +25,8 @@ ip_default_ttl - INTEGER ip_no_pmtu_disc - INTEGER Disable Path MTU Discovery. If enabled in mode 1 and a fragmentation-required ICMP is received, the PMTU to this - destination will be set to min_pmtu (see below). You will need + destination will be set to the smallest of the old MTU to + this destination and min_pmtu (see below). You will need to raise min_pmtu to the smallest interface MTU on your system manually if you want to avoid locally generated fragments. @@ -49,7 +50,8 @@ ip_no_pmtu_disc - INTEGER Default: FALSE min_pmtu - INTEGER - default 552 - minimum discovered Path MTU + default 552 - minimum Path MTU. Unless this is changed mannually, + each cached pmtu will never be lower than this setting. ip_forward_use_pmtu - BOOLEAN By default we don't trust protocol path MTUs while forwarding diff --git a/Documentation/networking/ipvs-sysctl.rst b/Documentation/networking/ipvs-sysctl.rst index 95ef56d62077..387fda80f05f 100644 --- a/Documentation/networking/ipvs-sysctl.rst +++ b/Documentation/networking/ipvs-sysctl.rst @@ -37,8 +37,7 @@ conn_reuse_mode - INTEGER 0: disable any special handling on port reuse. The new connection will be delivered to the same real server that was - servicing the previous connection. This will effectively - disable expire_nodest_conn. + servicing the previous connection. bit 1: enable rescheduling of new connections when it is safe. That is, whenever expire_nodest_conn and for TCP sockets, when diff --git a/Documentation/networking/net_failover.rst b/Documentation/networking/net_failover.rst index e143ab79a960..3a662f2b4d6e 100644 --- a/Documentation/networking/net_failover.rst +++ b/Documentation/networking/net_failover.rst @@ -35,7 +35,7 @@ To support this, the hypervisor needs to enable VIRTIO_NET_F_STANDBY feature on the virtio-net interface and assign the same MAC address to both virtio-net and VF interfaces. -Here is an example XML snippet that shows such configuration. +Here is an example libvirt XML snippet that shows such configuration: :: <interface type='network'> @@ -45,18 +45,32 @@ Here is an example XML snippet that shows such configuration. <model type='virtio'/> <driver name='vhost' queues='4'/> <link state='down'/> - <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/> + <teaming type='persistent'/> + <alias name='ua-backup0'/> </interface> <interface type='hostdev' managed='yes'> <mac address='52:54:00:00:12:53'/> <source> <address type='pci' domain='0x0000' bus='0x42' slot='0x02' function='0x5'/> </source> - <address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/> + <teaming type='transient' persistent='ua-backup0'/> </interface> +In this configuration, the first device definition is for the virtio-net +interface and this acts as the 'persistent' device indicating that this +interface will always be plugged in. This is specified by the 'teaming' tag with +required attribute type having value 'persistent'. The link state for the +virtio-net device is set to 'down' to ensure that the 'failover' netdev prefers +the VF passthrough device for normal communication. The virtio-net device will +be brought UP during live migration to allow uninterrupted communication. + +The second device definition is for the VF passthrough interface. Here the +'teaming' tag is provided with type 'transient' indicating that this device may +periodically be unplugged. A second attribute - 'persistent' is provided and +points to the alias name declared for the virtio-net device. + Booting a VM with the above configuration will result in the following 3 -netdevs created in the VM. +interfaces created in the VM: :: 4: ens10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 @@ -65,13 +79,36 @@ netdevs created in the VM. valid_lft 42482sec preferred_lft 42482sec inet6 fe80::97d8:db2:8c10:b6d6/64 scope link valid_lft forever preferred_lft forever - 5: ens10nsby: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master ens10 state UP group default qlen 1000 + 5: ens10nsby: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master ens10 state DOWN group default qlen 1000 link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff 7: ens11: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master ens10 state UP group default qlen 1000 link/ether 52:54:00:00:12:53 brd ff:ff:ff:ff:ff:ff -ens10 is the 'failover' master netdev, ens10nsby and ens11 are the slave -'standby' and 'primary' netdevs respectively. +Here, ens10 is the 'failover' master interface, ens10nsby is the slave 'standby' +virtio-net interface, and ens11 is the slave 'primary' VF passthrough interface. + +One point to note here is that some user space network configuration daemons +like systemd-networkd, ifupdown, etc, do not understand the 'net_failover' +device; and on the first boot, the VM might end up with both 'failover' device +and VF accquiring IP addresses (either same or different) from the DHCP server. +This will result in lack of connectivity to the VM. So some tweaks might be +needed to these network configuration daemons to make sure that an IP is +received only on the 'failover' device. + +Below is the patch snippet used with 'cloud-ifupdown-helper' script found on +Debian cloud images: + +:: + @@ -27,6 +27,8 @@ do_setup() { + local working="$cfgdir/.$INTERFACE" + local final="$cfgdir/$INTERFACE" + + + if [ -d "/sys/class/net/${INTERFACE}/master" ]; then exit 0; fi + + + if ifup --no-act "$INTERFACE" > /dev/null 2>&1; then + # interface is already known to ifupdown, no need to generate cfg + log "Skipping configuration generation for $INTERFACE" + Live Migration of a VM with SR-IOV VF & virtio-net in STANDBY mode ================================================================== @@ -80,40 +117,68 @@ net_failover also enables hypervisor controlled live migration to be supported with VMs that have direct attached SR-IOV VF devices by automatic failover to the paravirtual datapath when the VF is unplugged. -Here is a sample script that shows the steps to initiate live migration on -the source hypervisor. +Here is a sample script that shows the steps to initiate live migration from +the source hypervisor. Note: It is assumed that the VM is connected to a +software bridge 'br0' which has a single VF attached to it along with the vnet +device to the VM. This is not the VF that was passthrough'd to the VM (seen in +the vf.xml file). :: - # cat vf_xml + # cat vf.xml <interface type='hostdev' managed='yes'> <mac address='52:54:00:00:12:53'/> <source> <address type='pci' domain='0x0000' bus='0x42' slot='0x02' function='0x5'/> </source> - <address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/> + <teaming type='transient' persistent='ua-backup0'/> </interface> - # Source Hypervisor + # Source Hypervisor migrate.sh #!/bin/bash - DOMAIN=fedora27-tap01 - PF=enp66s0f0 - VF_NUM=5 - TAP_IF=tap01 - VF_XML= + DOMAIN=vm-01 + PF=ens6np0 + VF=ens6v1 # VF attached to the bridge. + VF_NUM=1 + TAP_IF=vmtap01 # virtio-net interface in the VM. + VF_XML=vf.xml MAC=52:54:00:00:12:53 ZERO_MAC=00:00:00:00:00:00 + # Set the virtio-net interface up. virsh domif-setlink $DOMAIN $TAP_IF up - bridge fdb del $MAC dev $PF master - virsh detach-device $DOMAIN $VF_XML + + # Remove the VF that was passthrough'd to the VM. + virsh detach-device --live --config $DOMAIN $VF_XML + ip link set $PF vf $VF_NUM mac $ZERO_MAC - virsh migrate --live $DOMAIN qemu+ssh://$REMOTE_HOST/system + # Add FDB entry for traffic to continue going to the VM via + # the VF -> br0 -> vnet interface path. + bridge fdb add $MAC dev $VF + bridge fdb add $MAC dev $TAP_IF master + + # Migrate the VM + virsh migrate --live --persistent $DOMAIN qemu+ssh://$REMOTE_HOST/system + + # Clean up FDB entries after migration completes. + bridge fdb del $MAC dev $VF + bridge fdb del $MAC dev $TAP_IF master - # Destination Hypervisor +On the destination hypervisor, a shared bridge 'br0' is created before migration +starts, and a VF from the destination PF is added to the bridge. Similarly an +appropriate FDB entry is added. + +The following script is executed on the destination hypervisor once migration +completes, and it reattaches the VF to the VM and brings down the virtio-net +interface. + +:: + # reattach-vf.sh #!/bin/bash - virsh attach-device $DOMAIN $VF_XML - virsh domif-setlink $DOMAIN $TAP_IF down + bridge fdb del 52:54:00:00:12:53 dev ens36v0 + bridge fdb del 52:54:00:00:12:53 dev vmtap01 master + virsh attach-device --config --live vm01 vf.xml + virsh domif-setlink vm01 vmtap01 down diff --git a/Documentation/networking/phy.rst b/Documentation/networking/phy.rst index 571ba08386e7..d43da709bf40 100644 --- a/Documentation/networking/phy.rst +++ b/Documentation/networking/phy.rst @@ -237,6 +237,11 @@ negotiation results. Some of the interface modes are described below: +``PHY_INTERFACE_MODE_SMII`` + This is serial MII, clocked at 125MHz, supporting 100M and 10M speeds. + Some details can be found in + https://opencores.org/ocsvn/smii/smii/trunk/doc/SMII.pdf + ``PHY_INTERFACE_MODE_1000BASEX`` This defines the 1000BASE-X single-lane serdes link as defined by the 802.3 standard section 36. The link operates at a fixed bit rate of diff --git a/Documentation/networking/rds.rst b/Documentation/networking/rds.rst index 44936c27ab3a..498395f5fbcb 100644 --- a/Documentation/networking/rds.rst +++ b/Documentation/networking/rds.rst @@ -1,6 +1,6 @@ .. SPDX-License-Identifier: GPL-2.0 -== +=== RDS === diff --git a/Documentation/networking/timestamping.rst b/Documentation/networking/timestamping.rst index a722eb30e014..f5809206eb93 100644 --- a/Documentation/networking/timestamping.rst +++ b/Documentation/networking/timestamping.rst @@ -486,8 +486,8 @@ of packets. Drivers are free to use a more permissive configuration than the requested configuration. It is expected that drivers should only implement directly the most generic mode that can be supported. For example if the hardware can -support HWTSTAMP_FILTER_V2_EVENT, then it should generally always upscale -HWTSTAMP_FILTER_V2_L2_SYNC_MESSAGE, and so forth, as HWTSTAMP_FILTER_V2_EVENT +support HWTSTAMP_FILTER_PTP_V2_EVENT, then it should generally always upscale +HWTSTAMP_FILTER_PTP_V2_L2_SYNC, and so forth, as HWTSTAMP_FILTER_PTP_V2_EVENT is more generic (and more useful to applications). A driver which supports hardware time stamping shall update the struct @@ -582,8 +582,8 @@ Time stamps for outgoing packets are to be generated as follows: and hardware timestamping is not possible (SKBTX_IN_PROGRESS not set). - As soon as the driver has sent the packet and/or obtained a hardware time stamp for it, it passes the time stamp back by - calling skb_hwtstamp_tx() with the original skb, the raw - hardware time stamp. skb_hwtstamp_tx() clones the original skb and + calling skb_tstamp_tx() with the original skb, the raw + hardware time stamp. skb_tstamp_tx() clones the original skb and adds the timestamps, therefore the original skb has to be freed now. If obtaining the hardware time stamp somehow fails, then the driver should not fall back to software time stamping. The rationale is that |