include/net/gue.h

Source file repositories/reference/linux-study-clean/include/net/gue.h

File Facts

System
Linux kernel
Corpus path
include/net/gue.h
Extension
.h
Size
3366 bytes
Lines
121
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

struct guehdr {
	union {
		struct {
#if defined(__LITTLE_ENDIAN_BITFIELD)
			__u8	hlen:5,
				control:1,
				version:2;
#elif defined (__BIG_ENDIAN_BITFIELD)
			__u8	version:2,
				control:1,
				hlen:5;
#else
#error  "Please fix <asm/byteorder.h>"
#endif
			__u8	proto_ctype;
			__be16	flags;
		};
		__be32	word;
	};
};

/* Standard flags in GUE header */

#define GUE_FLAG_PRIV	htons(1<<0)	/* Private flags are in options */
#define GUE_LEN_PRIV	4

#define GUE_FLAGS_ALL	(GUE_FLAG_PRIV)

/* Private flags in the private option extension */

#define GUE_PFLAG_REMCSUM	htonl(1U << 31)
#define GUE_PLEN_REMCSUM	4

#define GUE_PFLAGS_ALL	(GUE_PFLAG_REMCSUM)

/* Functions to compute options length corresponding to flags.
 * If we ever have a lot of flags this can be potentially be
 * converted to a more optimized algorithm (table lookup
 * for instance).
 */
static inline size_t guehdr_flags_len(__be16 flags)
{
	return ((flags & GUE_FLAG_PRIV) ? GUE_LEN_PRIV : 0);
}

static inline size_t guehdr_priv_flags_len(__be32 flags)
{
	return 0;
}

/* Validate standard and private flags. Returns non-zero (meaning invalid)
 * if there is an unknown standard or private flags, or the options length for
 * the flags exceeds the options length specific in hlen of the GUE header.
 */
static inline int validate_gue_flags(struct guehdr *guehdr, size_t optlen)
{
	__be16 flags = guehdr->flags;
	size_t len;

	if (flags & ~GUE_FLAGS_ALL)
		return 1;

	len = guehdr_flags_len(flags);
	if (len > optlen)
		return 1;

	if (flags & GUE_FLAG_PRIV) {
		/* Private flags are last four bytes accounted in
		 * guehdr_flags_len
		 */
		__be32 pflags = *(__be32 *)((void *)&guehdr[1] +
					    len - GUE_LEN_PRIV);

		if (pflags & ~GUE_PFLAGS_ALL)
			return 1;

		len += guehdr_priv_flags_len(pflags);
		if (len > optlen)
			return 1;
	}

	return 0;
}

#endif

Annotation

Implementation Notes