server_ipc.h

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#ifndef ATALK_SERVER_IPC_H
#define ATALK_SERVER_IPC_H
 
#include <stdint.h>
 
#include <atalk/cnid.h>
#include <atalk/globals.h>
#include <atalk/server_child.h>
 
/* IPC wire format constants — moved from server_ipc.c so receivers (Eg dircache.c)
 * can parse the wire format. 14-byte header: cmd(2) + pid(4) + uid(4) + len(4) */
#define IPC_HEADERLEN  14
#define IPC_MAXMSGSIZE 90
 
/* Remember to add IPC commands to server_ipc.c:ipc_cmd_str[] */
#define IPC_DISCOLDSESSION   0
#define IPC_GETSESSION       1
#define IPC_STATE            2  
#define IPC_VOLUMES          3  
#define IPC_LOGINDONE        4
#define IPC_CACHE_HINT       5  
#define IPC_SESSIONTOKEN     6  
 
/* Cache hint types — carried in struct ipc_cache_hint_payload.event */
#define CACHE_HINT_REFRESH          0  
#define CACHE_HINT_DELETE           1  
#define CACHE_HINT_DELETE_CHILDREN  2  
#define CACHE_HINT_VOLUME_RESET     3  
#define CACHE_HINT_COUNT            4  
 
/* Hint payload — sent inside standard IPC wire header framing.
 * Packed to guarantee sizeof == 8. vid and cnid in network byte order. */
struct __attribute__((packed)) ipc_cache_hint_payload {
    uint8_t   event;       /* Hint type: one of the CACHE_HINT_* values */
    uint8_t   reserved;    /* Alignment padding (could be version field in future) */
    uint16_t  vid;         /* Volume ID — network byte order (matches vol->v_vid) */
    cnid_t    cnid;        /* CNID of affected file/dir — network byte order */
};
 
_Static_assert(sizeof(struct ipc_cache_hint_payload) == 8,
               "Hint payload must be exactly 8 bytes");
 
/* Every event is validated against CACHE_HINT_COUNT, then used as an index */
_Static_assert(CACHE_HINT_REFRESH < CACHE_HINT_COUNT
               && CACHE_HINT_DELETE < CACHE_HINT_COUNT
               && CACHE_HINT_DELETE_CHILDREN < CACHE_HINT_COUNT
               && CACHE_HINT_VOLUME_RESET < CACHE_HINT_COUNT,
               "CACHE_HINT_COUNT must cover every CACHE_HINT_* value");
 
/* Hint buffer capacity — main.c checks this to trigger immediate flush
 * when buffer is full after fd event processing. */
#define HINT_BUF_SIZE           128
 
/* Flush interval for poll timeout — main.c uses this to set poll timeout
 * when hints are buffered. 50ms balances latency vs syscall overhead. */
#define HINT_FLUSH_INTERVAL_MS  50
 
extern int ipc_server_read(server_child_t *children, int fd);
extern int ipc_child_write(AFPObj *obj, uint16_t command, size_t len,
                           void *token);
extern int ipc_child_state(AFPObj *obj, uint16_t state);
 
extern int ipc_send_cache_hint(const AFPObj *obj, uint16_t vid, cnid_t cnid,
                               uint8_t event);
extern unsigned long long ipc_get_hints_sent(void);
extern unsigned long long ipc_get_hints_dropped(void);
 
/* Poll-driven hint flush API (parent-side only, single-threaded) */
extern void hint_flush_pending(server_child_t *children);
extern int  hint_buf_count(void);
 
#endif /* ATALK_SERVER_IPC_H */