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| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
|---|---|
| 2 | #ifndef __NET_GUE_H |
| 3 | #define __NET_GUE_H |
| 4 | |
| 5 | /* Definitions for the GUE header, standard and private flags, lengths |
| 6 | * of optional fields are below. |
| 7 | * |
| 8 | * Diagram of GUE header: |
| 9 | * |
| 10 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 11 | * |Ver|C| Hlen | Proto/ctype | Standard flags |P| |
| 12 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 13 | * | | |
| 14 | * ~ Fields (optional) ~ |
| 15 | * | | |
| 16 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 17 | * | Private flags (optional, P bit is set) | |
| 18 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 19 | * | | |
| 20 | * ~ Private fields (optional) ~ |
| 21 | * | | |
| 22 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 23 | * |
| 24 | * C bit indicates control message when set, data message when unset. |
| 25 | * For a control message, proto/ctype is interpreted as a type of |
| 26 | * control message. For data messages, proto/ctype is the IP protocol |
| 27 | * of the next header. |
| 28 | * |
| 29 | * P bit indicates private flags field is present. The private flags |
| 30 | * may refer to options placed after this field. |
| 31 | */ |
| 32 | |
| 33 | #include <asm/byteorder.h> |
| 34 | #include <linux/types.h> |
| 35 | |
| 36 | struct guehdr { |
| 37 | union { |
| 38 | struct { |
| 39 | #if defined(__LITTLE_ENDIAN_BITFIELD) |
| 40 | __u8 hlen:5, |
| 41 | control:1, |
| 42 | version:2; |
| 43 | #elif defined (__BIG_ENDIAN_BITFIELD) |
| 44 | __u8 version:2, |
| 45 | control:1, |
| 46 | hlen:5; |
| 47 | #else |
| 48 | #error "Please fix <asm/byteorder.h>" |
| 49 | #endif |
| 50 | __u8 proto_ctype; |
| 51 | __be16 flags; |
| 52 | }; |
| 53 | __be32 word; |
| 54 | }; |
| 55 | }; |
| 56 | |
| 57 | /* Standard flags in GUE header */ |
| 58 | |
| 59 | #define GUE_FLAG_PRIV htons(1<<0) /* Private flags are in options */ |
| 60 | #define GUE_LEN_PRIV 4 |
| 61 | |
| 62 | #define GUE_FLAGS_ALL (GUE_FLAG_PRIV) |
| 63 | |
| 64 | /* Private flags in the private option extension */ |
| 65 | |
| 66 | #define GUE_PFLAG_REMCSUM htonl(1U << 31) |
| 67 | #define GUE_PLEN_REMCSUM 4 |
| 68 | |
| 69 | #define GUE_PFLAGS_ALL (GUE_PFLAG_REMCSUM) |
| 70 | |
| 71 | /* Functions to compute options length corresponding to flags. |
| 72 | * If we ever have a lot of flags this can be potentially be |
| 73 | * converted to a more optimized algorithm (table lookup |
| 74 | * for instance). |
| 75 | */ |
| 76 | static inline size_t guehdr_flags_len(__be16 flags) |
| 77 | { |
| 78 | return ((flags & GUE_FLAG_PRIV) ? GUE_LEN_PRIV : 0); |
| 79 | } |
| 80 | |
| 81 | static inline size_t guehdr_priv_flags_len(__be32 flags) |
| 82 | { |
| 83 | return 0; |
| 84 | } |
| 85 | |
| 86 | /* Validate standard and private flags. Returns non-zero (meaning invalid) |
| 87 | * if there is an unknown standard or private flags, or the options length for |
| 88 | * the flags exceeds the options length specific in hlen of the GUE header. |
| 89 | */ |
| 90 | static inline int validate_gue_flags(struct guehdr *guehdr, size_t optlen) |
| 91 | { |
| 92 | __be16 flags = guehdr->flags; |
| 93 | size_t len; |
| 94 | |
| 95 | if (flags & ~GUE_FLAGS_ALL) |
| 96 | return 1; |
| 97 | |
| 98 | len = guehdr_flags_len(flags); |
| 99 | if (len > optlen) |
| 100 | return 1; |
| 101 | |
| 102 | if (flags & GUE_FLAG_PRIV) { |
| 103 | /* Private flags are last four bytes accounted in |
| 104 | * guehdr_flags_len |
| 105 | */ |
| 106 | __be32 pflags = *(__be32 *)((void *)&guehdr[1] + |
| 107 | len - GUE_LEN_PRIV); |
| 108 | |
| 109 | if (pflags & ~GUE_PFLAGS_ALL) |
| 110 | return 1; |
| 111 | |
| 112 | len += guehdr_priv_flags_len(pflags); |
| 113 | if (len > optlen) |
| 114 | return 1; |
| 115 | } |
| 116 | |
| 117 | return 0; |
| 118 | } |
| 119 | |
| 120 | #endif |
| 121 |
Warning: This file is not a C or C++ file. It does not have highlighting.