21  * going forward with future NSH specification updates.  It MUST be set
22  * to 0x0 by the sender, in this first revision of NSH.  Given the
53  * involved in forwarding an NSH packet MUST decrement the TTL value by
54  * 1 prior to NSH forwarding lookup.  Decrementing by 1 from an incoming
61  * other NSH supporting elements.  Elements which do not understand the
65  * Length: The total length, in 4-byte words, of NSH including the Base
69  * 0x2.  The length of the NSH header MUST be an integer multiple of 4
73  * MD Type: Indicates the format of NSH beyond the mandatory Base Header
94  * NSH does not alter the inner payload, and the semantics on the inner
95  * protocol remain unchanged due to NSH service function chaining.
103  * 0x4: NSH
127  * NSH.  The initial Classifier MUST send the packet to the first SFF in
190  * [0] https://datatracker.ietf.org/doc/draft-ietf-sfc-nsh/
194  * struct nsh_md1_ctx - Keeps track of NSH context data
195  * @context: NSH Contexts.
219 /* Masking NSH header fields. */
243 /* NSH Base Header Length */
246 /* NSH MD Type 1 header Length. */
249 /* NSH header maximum Length. */
252 /* NSH context headers maximum Length. */
260 static inline u16 nsh_hdr_len(const struct nshhdr *nsh)  in nsh_hdr_len()  argument
262 	return ((ntohs(nsh->ver_flags_ttl_len) & NSH_LEN_MASK)  in nsh_hdr_len()
266 static inline u8 nsh_get_ver(const struct nshhdr *nsh)  in nsh_get_ver()  argument
268 	return (ntohs(nsh->ver_flags_ttl_len) & NSH_VER_MASK)  in nsh_get_ver()
272 static inline u8 nsh_get_flags(const struct nshhdr *nsh)  in nsh_get_flags()  argument
274 	return (ntohs(nsh->ver_flags_ttl_len) & NSH_FLAGS_MASK)  in nsh_get_flags()
278 static inline u8 nsh_get_ttl(const struct nshhdr *nsh)  in nsh_get_ttl()  argument
280 	return (ntohs(nsh->ver_flags_ttl_len) & NSH_TTL_MASK)  in nsh_get_ttl()
284 static inline void __nsh_set_xflag(struct nshhdr *nsh, u16 xflag, u16 xmask)  in __nsh_set_xflag()  argument
286 	nsh->ver_flags_ttl_len  in __nsh_set_xflag()
287 		= (nsh->ver_flags_ttl_len & ~htons(xmask)) | htons(xflag);  in __nsh_set_xflag()
290 static inline void nsh_set_flags_and_ttl(struct nshhdr *nsh, u8 flags, u8 ttl)  in nsh_set_flags_and_ttl()  argument
292 	__nsh_set_xflag(nsh, ((flags << NSH_FLAGS_SHIFT) & NSH_FLAGS_MASK) |  in nsh_set_flags_and_ttl()
297 static inline void nsh_set_flags_ttl_len(struct nshhdr *nsh, u8 flags,  in nsh_set_flags_ttl_len()  argument
301 	__nsh_set_xflag(nsh, ((flags << NSH_FLAGS_SHIFT) & NSH_FLAGS_MASK) |  in nsh_set_flags_ttl_len()