mirror of
https://github.com/torvalds/linux.git
synced 2024-11-10 14:11:52 +00:00
d1533d726a
Use the struct member's name and the correct format to prevent a
kernel-doc warning.
nsh.h:200: warning: Function parameter or member 'context' not described in 'nsh_md1_ctx'
Fixes: 1f0b7744c5 ("net: add NSH header structures and helpers")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jiri Benc <jbenc@redhat.com>
Link: https://lore.kernel.org/r/20230714045127.18752-8-rdunlap@infradead.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
311 lines
12 KiB
C
311 lines
12 KiB
C
#ifndef __NET_NSH_H
|
|
#define __NET_NSH_H 1
|
|
|
|
#include <linux/skbuff.h>
|
|
|
|
/*
|
|
* Network Service Header:
|
|
* 0 1 2 3
|
|
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* |Ver|O|U| TTL | Length |U|U|U|U|MD Type| Next Protocol |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | Service Path Identifier (SPI) | Service Index |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | |
|
|
* ~ Mandatory/Optional Context Headers ~
|
|
* | |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
*
|
|
* Version: The version field is used to ensure backward compatibility
|
|
* going forward with future NSH specification updates. It MUST be set
|
|
* to 0x0 by the sender, in this first revision of NSH. Given the
|
|
* widespread implementation of existing hardware that uses the first
|
|
* nibble after an MPLS label stack for ECMP decision processing, this
|
|
* document reserves version 01b and this value MUST NOT be used in
|
|
* future versions of the protocol. Please see [RFC7325] for further
|
|
* discussion of MPLS-related forwarding requirements.
|
|
*
|
|
* O bit: Setting this bit indicates an Operations, Administration, and
|
|
* Maintenance (OAM) packet. The actual format and processing of SFC
|
|
* OAM packets is outside the scope of this specification (see for
|
|
* example [I-D.ietf-sfc-oam-framework] for one approach).
|
|
*
|
|
* The O bit MUST be set for OAM packets and MUST NOT be set for non-OAM
|
|
* packets. The O bit MUST NOT be modified along the SFP.
|
|
*
|
|
* SF/SFF/SFC Proxy/Classifier implementations that do not support SFC
|
|
* OAM procedures SHOULD discard packets with O bit set, but MAY support
|
|
* a configurable parameter to enable forwarding received SFC OAM
|
|
* packets unmodified to the next element in the chain. Forwarding OAM
|
|
* packets unmodified by SFC elements that do not support SFC OAM
|
|
* procedures may be acceptable for a subset of OAM functions, but can
|
|
* result in unexpected outcomes for others, thus it is recommended to
|
|
* analyze the impact of forwarding an OAM packet for all OAM functions
|
|
* prior to enabling this behavior. The configurable parameter MUST be
|
|
* disabled by default.
|
|
*
|
|
* TTL: Indicates the maximum SFF hops for an SFP. This field is used
|
|
* for service plane loop detection. The initial TTL value SHOULD be
|
|
* configurable via the control plane; the configured initial value can
|
|
* be specific to one or more SFPs. If no initial value is explicitly
|
|
* provided, the default initial TTL value of 63 MUST be used. Each SFF
|
|
* involved in forwarding an NSH packet MUST decrement the TTL value by
|
|
* 1 prior to NSH forwarding lookup. Decrementing by 1 from an incoming
|
|
* value of 0 shall result in a TTL value of 63. The packet MUST NOT be
|
|
* forwarded if TTL is, after decrement, 0.
|
|
*
|
|
* All other flag fields, marked U, are unassigned and available for
|
|
* future use, see Section 11.2.1. Unassigned bits MUST be set to zero
|
|
* upon origination, and MUST be ignored and preserved unmodified by
|
|
* other NSH supporting elements. Elements which do not understand the
|
|
* meaning of any of these bits MUST NOT modify their actions based on
|
|
* those unknown bits.
|
|
*
|
|
* Length: The total length, in 4-byte words, of NSH including the Base
|
|
* Header, the Service Path Header, the Fixed Length Context Header or
|
|
* Variable Length Context Header(s). The length MUST be 0x6 for MD
|
|
* Type equal to 0x1, and MUST be 0x2 or greater for MD Type equal to
|
|
* 0x2. The length of the NSH header MUST be an integer multiple of 4
|
|
* bytes, thus variable length metadata is always padded out to a
|
|
* multiple of 4 bytes.
|
|
*
|
|
* MD Type: Indicates the format of NSH beyond the mandatory Base Header
|
|
* and the Service Path Header. MD Type defines the format of the
|
|
* metadata being carried.
|
|
*
|
|
* 0x0 - This is a reserved value. Implementations SHOULD silently
|
|
* discard packets with MD Type 0x0.
|
|
*
|
|
* 0x1 - This indicates that the format of the header includes a fixed
|
|
* length Context Header (see Figure 4 below).
|
|
*
|
|
* 0x2 - This does not mandate any headers beyond the Base Header and
|
|
* Service Path Header, but may contain optional variable length Context
|
|
* Header(s). The semantics of the variable length Context Header(s)
|
|
* are not defined in this document. The format of the optional
|
|
* variable length Context Headers is provided in Section 2.5.1.
|
|
*
|
|
* 0xF - This value is reserved for experimentation and testing, as per
|
|
* [RFC3692]. Implementations not explicitly configured to be part of
|
|
* an experiment SHOULD silently discard packets with MD Type 0xF.
|
|
*
|
|
* Next Protocol: indicates the protocol type of the encapsulated data.
|
|
* NSH does not alter the inner payload, and the semantics on the inner
|
|
* protocol remain unchanged due to NSH service function chaining.
|
|
* Please see the IANA Considerations section below, Section 11.2.5.
|
|
*
|
|
* This document defines the following Next Protocol values:
|
|
*
|
|
* 0x1: IPv4
|
|
* 0x2: IPv6
|
|
* 0x3: Ethernet
|
|
* 0x4: NSH
|
|
* 0x5: MPLS
|
|
* 0xFE: Experiment 1
|
|
* 0xFF: Experiment 2
|
|
*
|
|
* Packets with Next Protocol values not supported SHOULD be silently
|
|
* dropped by default, although an implementation MAY provide a
|
|
* configuration parameter to forward them. Additionally, an
|
|
* implementation not explicitly configured for a specific experiment
|
|
* [RFC3692] SHOULD silently drop packets with Next Protocol values 0xFE
|
|
* and 0xFF.
|
|
*
|
|
* Service Path Identifier (SPI): Identifies a service path.
|
|
* Participating nodes MUST use this identifier for Service Function
|
|
* Path selection. The initial classifier MUST set the appropriate SPI
|
|
* for a given classification result.
|
|
*
|
|
* Service Index (SI): Provides location within the SFP. The initial
|
|
* classifier for a given SFP SHOULD set the SI to 255, however the
|
|
* control plane MAY configure the initial value of SI as appropriate
|
|
* (i.e., taking into account the length of the service function path).
|
|
* The Service Index MUST be decremented by a value of 1 by Service
|
|
* Functions or by SFC Proxy nodes after performing required services
|
|
* and the new decremented SI value MUST be used in the egress packet's
|
|
* NSH. The initial Classifier MUST send the packet to the first SFF in
|
|
* the identified SFP for forwarding along an SFP. If re-classification
|
|
* occurs, and that re-classification results in a new SPI, the
|
|
* (re)classifier is, in effect, the initial classifier for the
|
|
* resultant SPI.
|
|
*
|
|
* The SI is used in conjunction the with Service Path Identifier for
|
|
* Service Function Path Selection and for determining the next SFF/SF
|
|
* in the path. The SI is also valuable when troubleshooting or
|
|
* reporting service paths. Additionally, while the TTL field is the
|
|
* main mechanism for service plane loop detection, the SI can also be
|
|
* used for detecting service plane loops.
|
|
*
|
|
* When the Base Header specifies MD Type = 0x1, a Fixed Length Context
|
|
* Header (16-bytes) MUST be present immediately following the Service
|
|
* Path Header. The value of a Fixed Length Context
|
|
* Header that carries no metadata MUST be set to zero.
|
|
*
|
|
* When the base header specifies MD Type = 0x2, zero or more Variable
|
|
* Length Context Headers MAY be added, immediately following the
|
|
* Service Path Header (see Figure 5). Therefore, Length = 0x2,
|
|
* indicates that only the Base Header followed by the Service Path
|
|
* Header are present. The optional Variable Length Context Headers
|
|
* MUST be of an integer number of 4-bytes. The base header Length
|
|
* field MUST be used to determine the offset to locate the original
|
|
* packet or frame for SFC nodes that require access to that
|
|
* information.
|
|
*
|
|
* The format of the optional variable length Context Headers
|
|
*
|
|
* 0 1 2 3
|
|
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | Metadata Class | Type |U| Length |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | Variable Metadata |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
*
|
|
* Metadata Class (MD Class): Defines the scope of the 'Type' field to
|
|
* provide a hierarchical namespace. The IANA Considerations
|
|
* Section 11.2.4 defines how the MD Class values can be allocated to
|
|
* standards bodies, vendors, and others.
|
|
*
|
|
* Type: Indicates the explicit type of metadata being carried. The
|
|
* definition of the Type is the responsibility of the MD Class owner.
|
|
*
|
|
* Unassigned bit: One unassigned bit is available for future use. This
|
|
* bit MUST NOT be set, and MUST be ignored on receipt.
|
|
*
|
|
* Length: Indicates the length of the variable metadata, in bytes. In
|
|
* case the metadata length is not an integer number of 4-byte words,
|
|
* the sender MUST add pad bytes immediately following the last metadata
|
|
* byte to extend the metadata to an integer number of 4-byte words.
|
|
* The receiver MUST round up the length field to the nearest 4-byte
|
|
* word boundary, to locate and process the next field in the packet.
|
|
* The receiver MUST access only those bytes in the metadata indicated
|
|
* by the length field (i.e., actual number of bytes) and MUST ignore
|
|
* the remaining bytes up to the nearest 4-byte word boundary. The
|
|
* Length may be 0 or greater.
|
|
*
|
|
* A value of 0 denotes a Context Header without a Variable Metadata
|
|
* field.
|
|
*
|
|
* [0] https://datatracker.ietf.org/doc/draft-ietf-sfc-nsh/
|
|
*/
|
|
|
|
/**
|
|
* struct nsh_md1_ctx - Keeps track of NSH context data
|
|
* @context: NSH Contexts.
|
|
*/
|
|
struct nsh_md1_ctx {
|
|
__be32 context[4];
|
|
};
|
|
|
|
struct nsh_md2_tlv {
|
|
__be16 md_class;
|
|
u8 type;
|
|
u8 length;
|
|
u8 md_value[];
|
|
};
|
|
|
|
struct nshhdr {
|
|
__be16 ver_flags_ttl_len;
|
|
u8 mdtype;
|
|
u8 np;
|
|
__be32 path_hdr;
|
|
union {
|
|
struct nsh_md1_ctx md1;
|
|
struct nsh_md2_tlv md2;
|
|
};
|
|
};
|
|
|
|
/* Masking NSH header fields. */
|
|
#define NSH_VER_MASK 0xc000
|
|
#define NSH_VER_SHIFT 14
|
|
#define NSH_FLAGS_MASK 0x3000
|
|
#define NSH_FLAGS_SHIFT 12
|
|
#define NSH_TTL_MASK 0x0fc0
|
|
#define NSH_TTL_SHIFT 6
|
|
#define NSH_LEN_MASK 0x003f
|
|
#define NSH_LEN_SHIFT 0
|
|
|
|
#define NSH_MDTYPE_MASK 0x0f
|
|
#define NSH_MDTYPE_SHIFT 0
|
|
|
|
#define NSH_SPI_MASK 0xffffff00
|
|
#define NSH_SPI_SHIFT 8
|
|
#define NSH_SI_MASK 0x000000ff
|
|
#define NSH_SI_SHIFT 0
|
|
|
|
/* MD Type Registry. */
|
|
#define NSH_M_TYPE1 0x01
|
|
#define NSH_M_TYPE2 0x02
|
|
#define NSH_M_EXP1 0xFE
|
|
#define NSH_M_EXP2 0xFF
|
|
|
|
/* NSH Base Header Length */
|
|
#define NSH_BASE_HDR_LEN 8
|
|
|
|
/* NSH MD Type 1 header Length. */
|
|
#define NSH_M_TYPE1_LEN 24
|
|
|
|
/* NSH header maximum Length. */
|
|
#define NSH_HDR_MAX_LEN 256
|
|
|
|
/* NSH context headers maximum Length. */
|
|
#define NSH_CTX_HDRS_MAX_LEN 248
|
|
|
|
static inline struct nshhdr *nsh_hdr(struct sk_buff *skb)
|
|
{
|
|
return (struct nshhdr *)skb_network_header(skb);
|
|
}
|
|
|
|
static inline u16 nsh_hdr_len(const struct nshhdr *nsh)
|
|
{
|
|
return ((ntohs(nsh->ver_flags_ttl_len) & NSH_LEN_MASK)
|
|
>> NSH_LEN_SHIFT) << 2;
|
|
}
|
|
|
|
static inline u8 nsh_get_ver(const struct nshhdr *nsh)
|
|
{
|
|
return (ntohs(nsh->ver_flags_ttl_len) & NSH_VER_MASK)
|
|
>> NSH_VER_SHIFT;
|
|
}
|
|
|
|
static inline u8 nsh_get_flags(const struct nshhdr *nsh)
|
|
{
|
|
return (ntohs(nsh->ver_flags_ttl_len) & NSH_FLAGS_MASK)
|
|
>> NSH_FLAGS_SHIFT;
|
|
}
|
|
|
|
static inline u8 nsh_get_ttl(const struct nshhdr *nsh)
|
|
{
|
|
return (ntohs(nsh->ver_flags_ttl_len) & NSH_TTL_MASK)
|
|
>> NSH_TTL_SHIFT;
|
|
}
|
|
|
|
static inline void __nsh_set_xflag(struct nshhdr *nsh, u16 xflag, u16 xmask)
|
|
{
|
|
nsh->ver_flags_ttl_len
|
|
= (nsh->ver_flags_ttl_len & ~htons(xmask)) | htons(xflag);
|
|
}
|
|
|
|
static inline void nsh_set_flags_and_ttl(struct nshhdr *nsh, u8 flags, u8 ttl)
|
|
{
|
|
__nsh_set_xflag(nsh, ((flags << NSH_FLAGS_SHIFT) & NSH_FLAGS_MASK) |
|
|
((ttl << NSH_TTL_SHIFT) & NSH_TTL_MASK),
|
|
NSH_FLAGS_MASK | NSH_TTL_MASK);
|
|
}
|
|
|
|
static inline void nsh_set_flags_ttl_len(struct nshhdr *nsh, u8 flags,
|
|
u8 ttl, u8 len)
|
|
{
|
|
len = len >> 2;
|
|
__nsh_set_xflag(nsh, ((flags << NSH_FLAGS_SHIFT) & NSH_FLAGS_MASK) |
|
|
((ttl << NSH_TTL_SHIFT) & NSH_TTL_MASK) |
|
|
((len << NSH_LEN_SHIFT) & NSH_LEN_MASK),
|
|
NSH_FLAGS_MASK | NSH_TTL_MASK | NSH_LEN_MASK);
|
|
}
|
|
|
|
int nsh_push(struct sk_buff *skb, const struct nshhdr *pushed_nh);
|
|
int nsh_pop(struct sk_buff *skb);
|
|
|
|
#endif /* __NET_NSH_H */
|