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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 | #ifndef __NET_GUE_H #define __NET_GUE_H /* Definitions for the GUE header, standard and private flags, lengths * of optional fields are below. * * Diagram of GUE header: * * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * |Ver|C| Hlen | Proto/ctype | Standard flags |P| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | | * ~ Fields (optional) ~ * | | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Private flags (optional, P bit is set) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | | * ~ Private fields (optional) ~ * | | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * C bit indicates contol message when set, data message when unset. * For a control message, proto/ctype is interpreted as a type of * control message. For data messages, proto/ctype is the IP protocol * of the next header. * * P bit indicates private flags field is present. The private flags * may refer to options placed after this field. */ 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; __u16 flags; }; __u32 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(1 << 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) { size_t len; __be32 flags = guehdr->flags; 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 */ flags = *(__be32 *)((void *)&guehdr[1] + len - GUE_LEN_PRIV); if (flags & ~GUE_PFLAGS_ALL) return 1; len += guehdr_priv_flags_len(flags); if (len > optlen) return 1; } return 0; } #endif |