/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * inet_dscp.h: helpers for handling differentiated services codepoints (DSCP) * * DSCP is defined in RFC 2474: * * 0 1 2 3 4 5 6 7 * +---+---+---+---+---+---+---+---+ * | DSCP | CU | * +---+---+---+---+---+---+---+---+ * * DSCP: differentiated services codepoint * CU: currently unused * * The whole DSCP + CU bits form the DS field. * The DS field is also commonly called TOS or Traffic Class (for IPv6). * * Note: the CU bits are now used for Explicit Congestion Notification * (RFC 3168). */ #ifndef _INET_DSCP_H #define _INET_DSCP_H #include <linux/types.h> /* Special type for storing DSCP values. * * A dscp_t variable stores a DS field with the CU (ECN) bits cleared. * Using dscp_t allows to strictly separate DSCP and ECN bits, thus avoiding * bugs where ECN bits are erroneously taken into account during FIB lookups * or policy routing. * * Note: to get the real DSCP value contained in a dscp_t variable one would * have to do a bit shift after calling inet_dscp_to_dsfield(). We could have * a helper for that, but there's currently no users. */ typedef u8 __bitwise dscp_t; #define INET_DSCP_MASK 0xfc static inline dscp_t inet_dsfield_to_dscp(__u8 dsfield) { return (__force dscp_t)(dsfield & INET_DSCP_MASK); } static inline __u8 inet_dscp_to_dsfield(dscp_t dscp) { return (__force __u8)dscp; } static inline bool inet_validate_dscp(__u8 val) { return !(val & ~INET_DSCP_MASK); } #endif /* _INET_DSCP_H */