version.h

#ifndef VERSION_VERSION_H
#define VERSION_VERSION_H
 
#include "common/platform/sys/syscall.h"
 
/* QUIC version numbers and the version_information transport parameter
 * (RFC 9368) used for compatible version negotiation. */
 
#define VERSION_1 0x00000001u
#define VERSION_2 0x6b3343cfu /* RFC 9369 */
 
/* A reserved version matches the 0x?a?a?a?a GREASE pattern (RFC 8999 6) and
 * is never selected. */
int version_is_reserved(u32 version);
 
/* version_information transport parameter id (RFC 9368 3). */
#define TP_VERSION_INFORMATION 0x11
#define VI_MAX_AVAILABLE 16

typedef struct {
  u32 chosen;                      
  usz n_available;                 
  u32 available[VI_MAX_AVAILABLE]; 
} version_info;

typedef struct {
  const u32* list; 
  usz        n;    
} verlist;
 
static inline verlist verlist_of(const u32* list, usz n) {
  verlist v = {list, n};
  return v;
}
 
/* Encode the version_information TP (id, length, Chosen Version, Available
 * Versions) into buf of cap bytes. Returns bytes written, or 0. */
usz version_info_encode(u8* buf, usz cap, const version_info* vi);
 
/* Decode a version_information TP at buf (n readable). Returns bytes
 * consumed, or 0 on malformed input. Chosen must appear in Available for a
 * client-sent parameter; the caller validates that per RFC 9368 4. */
usz version_info_decode(const u8* buf, usz n, version_info* vi);
 
#endif