Line data    Source code

       1             : #ifndef HEADER_fd_src_waltz_resolv_fd_adns_h
       2             : #define HEADER_fd_src_waltz_resolv_fd_adns_h
       3             : 
       4             : /* fd_adns is a non-blocking IPv4 DNS client, for resolving hostnames
       5             :    from a tile run loop (inside the seccomp sandbox) without ever
       6             :    blocking on the network.  Queries for all outstanding names are in
       7             :    flight concurrently on a single UDP socket.
       8             : 
       9             :    Requests are queued with fd_adns_resolve and completions are polled
      10             :    out of fd_adns_advance, which the owner calls periodically (it only
      11             :    performs syscalls while requests are outstanding).  Names
      12             :    satisfiable locally (IPv4 literals, /etc/hosts) complete on the
      13             :    next advance.  Requires fd_netdb_open_fds to have been called
      14             :    (before the sandbox). */
      15             : 
      16             : #include "../../util/fd_util_base.h"
      17             : #include "../fd_fqdn.h"
      18             : 
      19           0 : #define FD_ADNS_MAGIC (0xF17EDA2CEADD5000) /* FIREDANCE ADNS V0 */
      20             : 
      21             : /* Max addresses delivered per name. */
      22           0 : #define FD_ADNS_ADDR_MAX (8UL)
      23             : 
      24             : struct fd_adns_result {
      25             :   ulong req_id;   /* caller's cookie from fd_adns_resolve */
      26             :   int   err;      /* 0 on success, else FD_EAI_* (FD_EAI_AGAIN if all
      27             :                      attempts timed out; the caller may re-queue) */
      28             :   ulong addr_cnt; /* >=1 on success, 0 on error */
      29             :   uint  addrs[ FD_ADNS_ADDR_MAX ]; /* network byte order */
      30             : };
      31             : 
      32             : typedef struct fd_adns_result fd_adns_result_t;
      33             : 
      34             : struct fd_adns_private;
      35             : typedef struct fd_adns_private fd_adns_t;
      36             : 
      37             : extern FD_TL ushort fd_adns_ns_port;
      38             : 
      39             : FD_PROTOTYPES_BEGIN
      40             : 
      41             : FD_FN_CONST ulong
      42             : fd_adns_align( void );
      43             : 
      44             : FD_FN_CONST ulong
      45             : fd_adns_footprint( ulong max_reqs );
      46             : 
      47             : void *
      48             : fd_adns_new( void * shmem,
      49             :              ulong  max_reqs,
      50             :              int    epoll_fd );
      51             : 
      52             : fd_adns_t *
      53             : fd_adns_join( void * shadns );
      54             : 
      55             : void *
      56             : fd_adns_leave( fd_adns_t * adns );
      57             : 
      58             : /* fd_adns_delete closes the client's UDP socket (required if the
      59             :    owner must not carry stray fds into a sandbox). */
      60             : 
      61             : void *
      62             : fd_adns_delete( void * shadns );
      63             : 
      64             : /* Queue name (cstr fitting in FD_FQDN_BUF_MAX bytes) for resolution.
      65             :    req_id is an opaque cookie returned with the result.  Returns 0 on
      66             :    success, -1 if the request table is full. */
      67             : 
      68             : int
      69             : fd_adns_resolve( fd_adns_t *  adns,
      70             :                  char const * name,
      71             :                  ulong        req_id );
      72             : 
      73             : /* Drive I/O forward (send due (re)tries, receive answers, expire
      74             :    requests that exhausted their attempts) and pop one completed
      75             :    request into *result.  Returns 1 if a result was popped, 0 if
      76             :    nothing has completed.  Call repeatedly until 0 to drain. */
      77             : 
      78             : int
      79             : fd_adns_advance( fd_adns_t *        adns,
      80             :                  long               now,
      81             :                  fd_adns_result_t * result );
      82             : 
      83             : /* fd_adns_next_deadline returns the earliest wallclock at which a
      84             :    pending request (re)sends, or LONG_MAX if none is pending. */
      85             : 
      86             : long
      87             : fd_adns_next_deadline( fd_adns_t const * adns );
      88             : 
      89             : FD_PROTOTYPES_END
      90             : 
      91             : #endif /* HEADER_fd_src_waltz_resolv_fd_adns_h */