diff options
Diffstat (limited to 'Documentation/networking')
| -rw-r--r-- | Documentation/networking/cdc_mbim.txt | 4 | ||||
| -rw-r--r-- | Documentation/networking/checksum-offloads.txt | 2 | ||||
| -rw-r--r-- | Documentation/networking/dsa/lan9303.txt | 6 | ||||
| -rw-r--r-- | Documentation/networking/gtp.txt | 103 | ||||
| -rw-r--r-- | Documentation/networking/ila.txt | 285 | ||||
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 12 | ||||
| -rw-r--r-- | Documentation/networking/netdev-FAQ.txt | 5 | ||||
| -rw-r--r-- | Documentation/networking/packet_mmap.txt | 2 |
8 files changed, 405 insertions, 14 deletions
diff --git a/Documentation/networking/cdc_mbim.txt b/Documentation/networking/cdc_mbim.txt index e4c376abbdad..4e68f0bc5dba 100644 --- a/Documentation/networking/cdc_mbim.txt +++ b/Documentation/networking/cdc_mbim.txt @@ -332,8 +332,8 @@ References [5] "MBIM (Mobile Broadband Interface Model) Registry" - http://compliance.usb.org/mbim/ -[6] "/dev/bus/usb filesystem output" - - Documentation/usb/proc_usb_info.txt +[6] "/sys/kernel/debug/usb/devices output format" + - Documentation/driver-api/usb/usb.rst [7] "/sys/bus/usb/devices/.../descriptors" - Documentation/ABI/stable/sysfs-bus-usb diff --git a/Documentation/networking/checksum-offloads.txt b/Documentation/networking/checksum-offloads.txt index d52d191bbb0c..27bc09cfcf6d 100644 --- a/Documentation/networking/checksum-offloads.txt +++ b/Documentation/networking/checksum-offloads.txt @@ -47,7 +47,7 @@ The requirements for GSO are more complicated, because when segmenting an (section 'E') for more details. A driver declares its offload capabilities in netdev->hw_features; see - Documentation/networking/netdev-features for more. Note that a device + Documentation/networking/netdev-features.txt for more. Note that a device which only advertises NETIF_F_IP[V6]_CSUM must still obey the csum_start and csum_offset given in the SKB; if it tries to deduce these itself in hardware (as some NICs do) the driver should check that the values in the diff --git a/Documentation/networking/dsa/lan9303.txt b/Documentation/networking/dsa/lan9303.txt index ec28683d107d..144b02b95207 100644 --- a/Documentation/networking/dsa/lan9303.txt +++ b/Documentation/networking/dsa/lan9303.txt @@ -1,9 +1,9 @@ LAN9303 Ethernet switch driver ============================== -The LAN9303 is a three port 10/100 ethernet switch with integrated phys for the -two external ethernet ports. The third port is an RMII/MII interface to a host -master network interface (e.g. fixed link). +The LAN9303 is a three port 10/100 Mbps ethernet switch with integrated phys for +the two external ethernet ports. The third port is an RMII/MII interface to a +host master network interface (e.g. fixed link). Driver details diff --git a/Documentation/networking/gtp.txt b/Documentation/networking/gtp.txt index 93e96750f103..0d9c18f05ec6 100644 --- a/Documentation/networking/gtp.txt +++ b/Documentation/networking/gtp.txt @@ -1,6 +1,7 @@ The Linux kernel GTP tunneling module ====================================================================== -Documentation by Harald Welte <laforge@gnumonks.org> +Documentation by Harald Welte <laforge@gnumonks.org> and + Andreas Schultz <aschultz@tpip.net> In 'drivers/net/gtp.c' you are finding a kernel-level implementation of a GTP tunnel endpoint. @@ -91,9 +92,13 @@ http://git.osmocom.org/libgtpnl/ == Protocol Versions == -There are two different versions of GTP-U: v0 and v1. Both are -implemented in the Kernel GTP module. Version 0 is a legacy version, -and deprecated from recent 3GPP specifications. +There are two different versions of GTP-U: v0 [GSM TS 09.60] and v1 +[3GPP TS 29.281]. Both are implemented in the Kernel GTP module. +Version 0 is a legacy version, and deprecated from recent 3GPP +specifications. + +GTP-U uses UDP for transporting PDUs. The receiving UDP port is 2151 +for GTPv1-U and 3386 for GTPv0-U. There are three versions of GTP-C: v0, v1, and v2. As the kernel doesn't implement GTP-C, we don't have to worry about this. It's the @@ -133,3 +138,93 @@ doe to a lack of user interest, it never got merged. In 2015, Andreas Schultz came to the rescue and fixed lots more bugs, extended it with new features and finally pushed all of us to get it mainline, where it was merged in 4.7.0. + +== Architectural Details == + +=== Local GTP-U entity and tunnel identification === + +GTP-U uses UDP for transporting PDU's. The receiving UDP port is 2152 +for GTPv1-U and 3386 for GTPv0-U. + +There is only one GTP-U entity (and therefor SGSN/GGSN/S-GW/PDN-GW +instance) per IP address. Tunnel Endpoint Identifier (TEID) are unique +per GTP-U entity. + +A specific tunnel is only defined by the destination entity. Since the +destination port is constant, only the destination IP and TEID define +a tunnel. The source IP and Port have no meaning for the tunnel. + +Therefore: + + * when sending, the remote entity is defined by the remote IP and + the tunnel endpoint id. The source IP and port have no meaning and + can be changed at any time. + + * when receiving the local entity is defined by the local + destination IP and the tunnel endpoint id. The source IP and port + have no meaning and can change at any time. + +[3GPP TS 29.281] Section 4.3.0 defines this so: + +> The TEID in the GTP-U header is used to de-multiplex traffic +> incoming from remote tunnel endpoints so that it is delivered to the +> User plane entities in a way that allows multiplexing of different +> users, different packet protocols and different QoS levels. +> Therefore no two remote GTP-U endpoints shall send traffic to a +> GTP-U protocol entity using the same TEID value except +> for data forwarding as part of mobility procedures. + +The definition above only defines that two remote GTP-U endpoints +*should not* send to the same TEID, it *does not* forbid or exclude +such a scenario. In fact, the mentioned mobility procedures make it +necessary that the GTP-U entity accepts traffic for TEIDs from +multiple or unknown peers. + +Therefore, the receiving side identifies tunnels exclusively based on +TEIDs, not based on the source IP! + +== APN vs. Network Device == + +The GTP-U driver creates a Linux network device for each Gi/SGi +interface. + +[3GPP TS 29.281] calls the Gi/SGi reference point an interface. This +may lead to the impression that the GGSN/P-GW can have only one such +interface. + +Correct is that the Gi/SGi reference point defines the interworking +between +the 3GPP packet domain (PDN) based on GTP-U tunnel and IP +based networks. + +There is no provision in any of the 3GPP documents that limits the +number of Gi/SGi interfaces implemented by a GGSN/P-GW. + +[3GPP TS 29.061] Section 11.3 makes it clear that the selection of a +specific Gi/SGi interfaces is made through the Access Point Name +(APN): + +> 2. each private network manages its own addressing. In general this +> will result in different private networks having overlapping +> address ranges. A logically separate connection (e.g. an IP in IP +> tunnel or layer 2 virtual circuit) is used between the GGSN/P-GW +> and each private network. +> +> In this case the IP address alone is not necessarily unique. The +> pair of values, Access Point Name (APN) and IPv4 address and/or +> IPv6 prefixes, is unique. + +In order to support the overlapping address range use case, each APN +is mapped to a separate Gi/SGi interface (network device). + +NOTE: The Access Point Name is purely a control plane (GTP-C) concept. +At the GTP-U level, only Tunnel Endpoint Identifiers are present in +GTP-U packets and network devices are known + +Therefore for a given UE the mapping in IP to PDN network is: + * network device + MS IP -> Peer IP + Peer TEID, + +and from PDN to IP network: + * local GTP-U IP + TEID -> network device + +Furthermore, before a received T-PDU is injected into the network +device the MS IP is checked against the IP recorded in PDP context. diff --git a/Documentation/networking/ila.txt b/Documentation/networking/ila.txt new file mode 100644 index 000000000000..78df879abd26 --- /dev/null +++ b/Documentation/networking/ila.txt @@ -0,0 +1,285 @@ +Identifier Locator Addressing (ILA) + + +Introduction +============ + +Identifier-locator addressing (ILA) is a technique used with IPv6 that +differentiates between location and identity of a network node. Part of an +address expresses the immutable identity of the node, and another part +indicates the location of the node which can be dynamic. Identifier-locator +addressing can be used to efficiently implement overlay networks for +network virtualization as well as solutions for use cases in mobility. + +ILA can be thought of as means to implement an overlay network without +encapsulation. This is accomplished by performing network address +translation on destination addresses as a packet traverses a network. To +the network, an ILA translated packet appears to be no different than any +other IPv6 packet. For instance, if the transport protocol is TCP then an +ILA translated packet looks like just another TCP/IPv6 packet. The +advantage of this is that ILA is transparent to the network so that +optimizations in the network, such as ECMP, RSS, GRO, GSO, etc., just work. + +The ILA protocol is described in Internet-Draft draft-herbert-intarea-ila. + + +ILA terminology +=============== + + - Identifier A number that identifies an addressable node in the network + independent of its location. ILA identifiers are sixty-four + bit values. + + - Locator A network prefix that routes to a physical host. Locators + provide the topological location of an addressed node. ILA + locators are sixty-four bit prefixes. + + - ILA mapping + A mapping of an ILA identifier to a locator (or to a + locator and meta data). An ILA domain maintains a database + that contains mappings for all destinations in the domain. + + - SIR address + An IPv6 address composed of a SIR prefix (upper sixty- + four bits) and an identifier (lower sixty-four bits). + SIR addresses are visible to applications and provide a + means for them to address nodes independent of their + location. + + - ILA address + An IPv6 address composed of a locator (upper sixty-four + bits) and an identifier (low order sixty-four bits). ILA + addresses are never visible to an application. + + - ILA host An end host that is capable of performing ILA translations + on transmit or receive. + + - ILA router A network node that performs ILA translation and forwarding + of translated packets. + + - ILA forwarding cache + A type of ILA router that only maintains a working set + cache of mappings. + + - ILA node A network node capable of performing ILA translations. This + can be an ILA router, ILA forwarding cache, or ILA host. + + +Operation +========= + +There are two fundamental operations with ILA: + + - Translate a SIR address to an ILA address. This is performed on ingress + to an ILA overlay. + + - Translate an ILA address to a SIR address. This is performed on egress + from the ILA overlay. + +ILA can be deployed either on end hosts or intermediate devices in the +network; these are provided by "ILA hosts" and "ILA routers" respectively. +Configuration and datapath for these two points of deployment is somewhat +different. + +The diagram below illustrates the flow of packets through ILA as well +as showing ILA hosts and routers. + + +--------+ +--------+ + | Host A +-+ +--->| Host B | + | | | (2) ILA (') | | + +--------+ | ...addressed.... ( ) +--------+ + V +---+--+ . packet . +---+--+ (_) + (1) SIR | | ILA |----->-------->---->| ILA | | (3) SIR + addressed +->|router| . . |router|->-+ addressed + packet +---+--+ . IPv6 . +---+--+ packet + / . Network . + / . . +--+-++--------+ + +--------+ / . . |ILA || Host | + | Host +--+ . .- -|host|| | + | | . . +--+-++--------+ + +--------+ ................ + + +Transport checksum handling +=========================== + +When an address is translated by ILA, an encapsulated transport checksum +that includes the translated address in a pseudo header may be rendered +incorrect on the wire. This is a problem for intermediate devices, +including checksum offload in NICs, that process the checksum. There are +three options to deal with this: + +- no action Allow the checksum to be incorrect on the wire. Before + a receiver verifies a checksum the ILA to SIR address + translation must be done. + +- adjust transport checksum + When ILA translation is performed the packet is parsed + and if a transport layer checksum is found then it is + adjusted to reflect the correct checksum per the + translated address. + +- checksum neutral mapping + When an address is translated the difference can be offset + elsewhere in a part of the packet that is covered by the + the checksum. The low order sixteen bits of the identifier + are used. This method is preferred since it doesn't require + parsing a packet beyond the IP header and in most cases the + adjustment can be precomputed and saved with the mapping. + +Note that the checksum neutral adjustment affects the low order sixteen +bits of the identifier. When ILA to SIR address translation is done on +egress the low order bits are restored to the original value which +restores the identifier as it was originally sent. + + +Identifier types +================ + +ILA defines different types of identifiers for different use cases. + +The defined types are: + + 0: interface identifier + + 1: locally unique identifier + + 2: virtual networking identifier for IPv4 address + + 3: virtual networking identifier for IPv6 unicast address + + 4: virtual networking identifier for IPv6 multicast address + + 5: non-local address identifier + +In the current implementation of kernel ILA only locally unique identifiers +(LUID) are supported. LUID allows for a generic, unformatted 64 bit +identifier. + + +Identifier formats +================== + +Kernel ILA supports two optional fields in an identifier for formatting: +"C-bit" and "identifier type". The presence of these fields is determined +by configuration as demonstrated below. + +If the identifier type is present it occupies the three highest order +bits of an identifier. The possible values are given in the above list. + +If the C-bit is present, this is used as an indication that checksum +neutral mapping has been done. The C-bit can only be set in an +ILA address, never a SIR address. + +In the simplest format the identifier types, C-bit, and checksum +adjustment value are not present so an identifier is considered an +unstructured sixty-four bit value. + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Identifier | + + + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +The checksum neutral adjustment may be configured to always be +present using neutral-map-auto. In this case there is no C-bit, but the +checksum adjustment is in the low order 16 bits. The identifier is +still sixty-four bits. + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Identifier | + | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | Checksum-neutral adjustment | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +The C-bit may used to explicitly indicate that checksum neutral +mapping has been applied to an ILA address. The format is: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | |C| Identifier | + | +-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | Checksum-neutral adjustment | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +The identifier type field may be present to indicate the identifier +type. If it is not present then the type is inferred based on mapping +configuration. The checksum neutral adjustment may automatically +used with the identifier type as illustrated below. + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type| Identifier | + +-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | Checksum-neutral adjustment | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +If the identifier type and the C-bit can be present simultaneously so +the identifier format would be: + + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type|C| Identifier | + +-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | Checksum-neutral adjustment | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + +Configuration +============= + +There are two methods to configure ILA mappings. One is by using LWT routes +and the other is ila_xlat (called from NFHOOK PREROUTING hook). ila_xlat +is intended to be used in the receive path for ILA hosts . + +An ILA router has also been implemented in XDP. Description of that is +outside the scope of this document. + +The usage of for ILA LWT routes is: + +ip route add DEST/128 encap ila LOC csum-mode MODE ident-type TYPE via ADDR + +Destination (DEST) can either be a SIR address (for an ILA host or ingress +ILA router) or an ILA address (egress ILA router). LOC is the sixty-four +bit locator (with format W:X:Y:Z) that overwrites the upper sixty-four +bits of the destination address. Checksum MODE is one of "no-action", +"adj-transport", "neutral-map", and "neutral-map-auto". If neutral-map is +set then the C-bit will be present. Identifier TYPE one of "luid" or +"use-format." In the case of use-format, the identifier type field is +present and the effective type is taken from that. + +The usage of ila_xlat is: + +ip ila add loc_match MATCH loc LOC csum-mode MODE ident-type TYPE + +MATCH indicates the incoming locator that must be matched to apply +a the translaiton. LOC is the locator that overwrites the upper +sixty-four bits of the destination address. MODE and TYPE have the +same meanings as described above. + + +Some examples +============= + +# Configure an ILA route that uses checksum neutral mapping as well +# as type field. Note that the type field is set in the SIR address +# (the 2000 implies type is 1 which is LUID). +ip route add 3333:0:0:1:2000:0:1:87/128 encap ila 2001:0:87:0 \ + csum-mode neutral-map ident-type use-format + +# Configure an ILA LWT route that uses auto checksum neutral mapping +# (no C-bit) and configure identifier type to be LUID so that the +# identifier type field will not be present. +ip route add 3333:0:0:1:2000:0:2:87/128 encap ila 2001:0:87:1 \ + csum-mode neutral-map-auto ident-type luid + +ila_xlat configuration + +# Configure an ILA to SIR mapping that matches a locator and overwrites +# it with a SIR address (3333:0:0:1 in this example). The C-bit and +# identifier field are used. +ip ila add loc_match 2001:0:119:0 loc 3333:0:0:1 \ + csum-mode neutral-map-auto ident-type use-format + +# Configure an ILA to SIR mapping where checksum neutral is automatically +# set without the C-bit and the identifier type is configured to be LUID +# so that the identifier type field is not present. +ip ila add loc_match 2001:0:119:0 loc 3333:0:0:1 \ + csum-mode neutral-map-auto ident-type use-format diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 54410a1d4065..46c7e1085efc 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -289,8 +289,7 @@ tcp_ecn_fallback - BOOLEAN Default: 1 (fallback enabled) tcp_fack - BOOLEAN - Enable FACK congestion avoidance and fast retransmission. - The value is not used, if tcp_sack is not enabled. + This is a legacy option, it has no effect anymore. tcp_fin_timeout - INTEGER The length of time an orphaned (no longer referenced by any @@ -1732,6 +1731,15 @@ ndisc_notify - BOOLEAN 1 - Generate unsolicited neighbour advertisements when device is brought up or hardware address changes. +ndisc_tclass - INTEGER + The IPv6 Traffic Class to use by default when sending IPv6 Neighbor + Discovery (Router Solicitation, Router Advertisement, Neighbor + Solicitation, Neighbor Advertisement, Redirect) messages. + These 8 bits can be interpreted as 6 high order bits holding the DSCP + value and 2 low order bits representing ECN (which you probably want + to leave cleared). + 0 - (default) + mldv1_unsolicited_report_interval - INTEGER The interval in milliseconds in which the next unsolicited MLDv1 report retransmit will take place. diff --git a/Documentation/networking/netdev-FAQ.txt b/Documentation/networking/netdev-FAQ.txt index cfc66ea72329..2a3278d5cf35 100644 --- a/Documentation/networking/netdev-FAQ.txt +++ b/Documentation/networking/netdev-FAQ.txt @@ -64,7 +64,10 @@ A: To understand this, you need to know a bit of background information If you aren't subscribed to netdev and/or are simply unsure if net-next has re-opened yet, simply check the net-next git repository link above for - any new networking-related commits. + any new networking-related commits. You may also check the following + website for the current status: + + http://vger.kernel.org/~davem/net-next.html The "net" tree continues to collect fixes for the vX.Y content, and is fed back to Linus at regular (~weekly) intervals. Meaning that the diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt index f3b9e507ab05..bf654845556e 100644 --- a/Documentation/networking/packet_mmap.txt +++ b/Documentation/networking/packet_mmap.txt @@ -1055,7 +1055,7 @@ TX_RING part only TP_STATUS_AVAILABLE is set, then the tp_sec and tp_{n,u}sec members do not contain a valid value. For TX_RINGs, by default no timestamp is generated! -See include/linux/net_tstamp.h and Documentation/networking/timestamping +See include/linux/net_tstamp.h and Documentation/networking/timestamping.txt for more information on hardware timestamps. ------------------------------------------------------------------------------- |
