From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ... --- Documentation/networking/ipvlan.rst | 189 ++++++++++++++++++++++++++++++++++++ 1 file changed, 189 insertions(+) create mode 100644 Documentation/networking/ipvlan.rst (limited to 'Documentation/networking/ipvlan.rst') diff --git a/Documentation/networking/ipvlan.rst b/Documentation/networking/ipvlan.rst new file mode 100644 index 000000000..895d0ccfd --- /dev/null +++ b/Documentation/networking/ipvlan.rst @@ -0,0 +1,189 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================== +IPVLAN Driver HOWTO +=================== + +Initial Release: + Mahesh Bandewar + +1. Introduction: +================ +This is conceptually very similar to the macvlan driver with one major +exception of using L3 for mux-ing /demux-ing among slaves. This property makes +the master device share the L2 with its slave devices. I have developed this +driver in conjunction with network namespaces and not sure if there is use case +outside of it. + + +2. Building and Installation: +============================= + +In order to build the driver, please select the config item CONFIG_IPVLAN. +The driver can be built into the kernel (CONFIG_IPVLAN=y) or as a module +(CONFIG_IPVLAN=m). + + +3. Configuration: +================= + +There are no module parameters for this driver and it can be configured +using IProute2/ip utility. +:: + + ip link add link name type ipvlan [ mode MODE ] [ FLAGS ] + where + MODE: l3 (default) | l3s | l2 + FLAGS: bridge (default) | private | vepa + +e.g. + + (a) Following will create IPvlan link with eth0 as master in + L3 bridge mode:: + + bash# ip link add link eth0 name ipvl0 type ipvlan + (b) This command will create IPvlan link in L2 bridge mode:: + + bash# ip link add link eth0 name ipvl0 type ipvlan mode l2 bridge + + (c) This command will create an IPvlan device in L2 private mode:: + + bash# ip link add link eth0 name ipvlan type ipvlan mode l2 private + + (d) This command will create an IPvlan device in L2 vepa mode:: + + bash# ip link add link eth0 name ipvlan type ipvlan mode l2 vepa + + +4. Operating modes: +=================== + +IPvlan has two modes of operation - L2 and L3. For a given master device, +you can select one of these two modes and all slaves on that master will +operate in the same (selected) mode. The RX mode is almost identical except +that in L3 mode the slaves won't receive any multicast / broadcast traffic. +L3 mode is more restrictive since routing is controlled from the other (mostly) +default namespace. + +4.1 L2 mode: +------------ + +In this mode TX processing happens on the stack instance attached to the +slave device and packets are switched and queued to the master device to send +out. In this mode the slaves will RX/TX multicast and broadcast (if applicable) +as well. + +4.2 L3 mode: +------------ + +In this mode TX processing up to L3 happens on the stack instance attached +to the slave device and packets are switched to the stack instance of the +master device for the L2 processing and routing from that instance will be +used before packets are queued on the outbound device. In this mode the slaves +will not receive nor can send multicast / broadcast traffic. + +4.3 L3S mode: +------------- + +This is very similar to the L3 mode except that iptables (conn-tracking) +works in this mode and hence it is L3-symmetric (L3s). This will have slightly less +performance but that shouldn't matter since you are choosing this mode over plain-L3 +mode to make conn-tracking work. + +5. Mode flags: +============== + +At this time following mode flags are available + +5.1 bridge: +----------- +This is the default option. To configure the IPvlan port in this mode, +user can choose to either add this option on the command-line or don't specify +anything. This is the traditional mode where slaves can cross-talk among +themselves apart from talking through the master device. + +5.2 private: +------------ +If this option is added to the command-line, the port is set in private +mode. i.e. port won't allow cross communication between slaves. + +5.3 vepa: +--------- +If this is added to the command-line, the port is set in VEPA mode. +i.e. port will offload switching functionality to the external entity as +described in 802.1Qbg +Note: VEPA mode in IPvlan has limitations. IPvlan uses the mac-address of the +master-device, so the packets which are emitted in this mode for the adjacent +neighbor will have source and destination mac same. This will make the switch / +router send the redirect message. + +6. What to choose (macvlan vs. ipvlan)? +======================================= + +These two devices are very similar in many regards and the specific use +case could very well define which device to choose. if one of the following +situations defines your use case then you can choose to use ipvlan: + + +(a) The Linux host that is connected to the external switch / router has + policy configured that allows only one mac per port. +(b) No of virtual devices created on a master exceed the mac capacity and + puts the NIC in promiscuous mode and degraded performance is a concern. +(c) If the slave device is to be put into the hostile / untrusted network + namespace where L2 on the slave could be changed / misused. + + +6. Example configuration: +========================= + +:: + + +=============================================================+ + | Host: host1 | + | | + | +----------------------+ +----------------------+ | + | | NS:ns0 | | NS:ns1 | | + | | | | | | + | | | | | | + | | ipvl0 | | ipvl1 | | + | +----------#-----------+ +-----------#----------+ | + | # # | + | ################################ | + | # eth0 | + +==============================#==============================+ + + +(a) Create two network namespaces - ns0, ns1:: + + ip netns add ns0 + ip netns add ns1 + +(b) Create two ipvlan slaves on eth0 (master device):: + + ip link add link eth0 ipvl0 type ipvlan mode l2 + ip link add link eth0 ipvl1 type ipvlan mode l2 + +(c) Assign slaves to the respective network namespaces:: + + ip link set dev ipvl0 netns ns0 + ip link set dev ipvl1 netns ns1 + +(d) Now switch to the namespace (ns0 or ns1) to configure the slave devices + + - For ns0:: + + (1) ip netns exec ns0 bash + (2) ip link set dev ipvl0 up + (3) ip link set dev lo up + (4) ip -4 addr add 127.0.0.1 dev lo + (5) ip -4 addr add $IPADDR dev ipvl0 + (6) ip -4 route add default via $ROUTER dev ipvl0 + + - For ns1:: + + (1) ip netns exec ns1 bash + (2) ip link set dev ipvl1 up + (3) ip link set dev lo up + (4) ip -4 addr add 127.0.0.1 dev lo + (5) ip -4 addr add $IPADDR dev ipvl1 + (6) ip -4 route add default via $ROUTER dev ipvl1 -- cgit v1.3.1