| 1 |
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| 2 | #ifndef __NET_GUE_H
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| 3 | #define __NET_GUE_H
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| 4 |
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| 5 | |
| 6 | * of optional fields are below.
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| 7 | *
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| 8 | * Diagram of GUE header:
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| 9 | *
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| 10 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 11 | * |Ver|C| Hlen | Proto/ctype | Standard flags |P|
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| 12 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 13 | * | |
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| 14 | * ~ Fields (optional) ~
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| 15 | * | |
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| 16 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 17 | * | Private flags (optional, P bit is set) |
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| 18 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 19 | * | |
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| 20 | * ~ Private fields (optional) ~
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| 21 | * | |
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| 22 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 23 | *
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| 24 | * C bit indicates control message when set, data message when unset.
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| 25 | * For a control message, proto/ctype is interpreted as a type of
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| 26 | * control message. For data messages, proto/ctype is the IP protocol
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| 27 | * of the next header.
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| 28 | *
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| 29 | * P bit indicates private flags field is present. The private flags
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| 30 | * may refer to options placed after this field.
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| 31 |
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| 32 |
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| 33 | #include <asm/byteorder.h>
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| 34 | #include <linux/types.h>
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| 35 |
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| 36 | struct guehdr {
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| 37 | union {
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| 38 | struct {
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| 39 | #if defined(__LITTLE_ENDIAN_BITFIELD)
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| 40 | __u8 hlen:5,
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| 41 | control:1,
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| 42 | version:2;
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| 43 | #elif defined (__BIG_ENDIAN_BITFIELD)
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| 44 | __u8 version:2,
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| 45 | control:1,
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| 46 | hlen:5;
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| 47 | #else
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| 48 | #error "Please fix <asm/byteorder.h>"
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| 49 | #endif
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| 50 | __u8 proto_ctype;
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| 51 | __be16 flags;
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| 52 | };
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| 53 | __be32 word;
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| 54 | };
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| 55 | };
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| 56 |
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| 57 |
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| 58 |
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| 59 | #define GUE_FLAG_PRIV htons(1<<0)
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| 60 | #define GUE_LEN_PRIV 4
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| 61 |
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| 62 | #define GUE_FLAGS_ALL (GUE_FLAG_PRIV)
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| 63 |
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| 64 |
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| 65 |
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| 66 | #define GUE_PFLAG_REMCSUM htonl(1U << 31)
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| 67 | #define GUE_PLEN_REMCSUM 4
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| 68 |
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| 69 | #define GUE_PFLAGS_ALL (GUE_PFLAG_REMCSUM)
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| 70 |
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| 71 | |
| 72 | * If we ever have a lot of flags this can be potentially be
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| 73 | * converted to a more optimized algorithm (table lookup
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| 74 | * for instance).
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| 75 |
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| 76 | static inline size_t guehdr_flags_len(__be16 flags)
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| 77 | {
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| 78 | return ((flags & GUE_FLAG_PRIV) ? GUE_LEN_PRIV : 0);
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| 79 | }
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| 80 |
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| 81 | static inline size_t guehdr_priv_flags_len(__be32 flags)
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| 82 | {
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| 83 | return (flags & GUE_PFLAG_REMCSUM) ? GUE_PLEN_REMCSUM : 0;
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| 84 | }
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| 85 |
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| 86 | |
| 87 | * if there is an unknown standard or private flags, if the options length for
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| 88 | * the flags exceeds the options length specified in hlen of the GUE header, or
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| 89 | * if a private option contains invalid data.
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| 90 |
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| 91 | static inline int validate_gue_flags(struct guehdr *guehdr, size_t optlen)
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| 92 | {
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| 93 | __be16 flags = guehdr->flags;
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| 94 | size_t len;
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| 95 |
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| 96 | if (flags & ~GUE_FLAGS_ALL)
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| 97 | return 1;
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| 98 |
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| 99 | len = guehdr_flags_len(flags);
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| 100 | if (len > optlen)
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| 101 | return 1;
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| 102 |
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| 103 | if (flags & GUE_FLAG_PRIV) {
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| 104 | |
| 105 | * guehdr_flags_len
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| 106 |
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| 107 | void *data = (void *)&guehdr[1] + len;
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| 108 | __be32 pflags = *(__be32 *)(data - GUE_LEN_PRIV);
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| 109 |
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| 110 | if (pflags & ~GUE_PFLAGS_ALL)
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| 111 | return 1;
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| 112 |
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| 113 | len += guehdr_priv_flags_len(pflags);
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| 114 | if (len > optlen)
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| 115 | return 1;
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| 116 |
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| 117 | if (pflags & GUE_PFLAG_REMCSUM) {
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| 118 | __be16 *pd = data;
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| 119 |
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| 120 | |
| 121 | * than the start pd[0].
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| 122 |
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| 123 | if (ntohs(pd[1]) < ntohs(pd[0]))
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| 124 | return 1;
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| 125 | }
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| 126 | }
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| 127 |
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| 128 | return 0;
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| 129 | }
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| 130 |
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| 131 | #endif
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