X-Git-Url: https://git.distorted.org.uk/~mdw/mLib/blobdiff_plain/dd3c57bc8cac59e0d657ee665ce462988d27d714..18c831dcd0ae4d660c70ccac69d27ed2a97851be:/sel/bres.h

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+/* -*-c-*-
+ *
+ * Background reverse name resolution
+ *
+ * (c) 1999 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of the mLib utilities library.
+ *
+ * mLib is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * mLib is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with mLib; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#ifndef MLIB_RES_H
+#define MLIB_RES_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <sys/types.h>
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+#ifdef HAVE_ADNS
+#  include <adns.h>
+#endif
+
+#ifndef MLIB_SEL_H
+#  include "sel.h"
+#endif
+
+#ifndef MLIB_SELBUF_H
+#  include "selbuf.h"
+#endif
+
+/*----- Data structures ---------------------------------------------------*/
+
+/* --- Client allocated request block --- */
+
+typedef struct bres_client {
+#ifdef HAVE_ADNS
+  adns_query aq;			/* ADNS query handle */
+  adns_answer *a;			/* Answer for reverse resolution */
+  struct _unused *_pad1;		/* And a spare slot */
+#else
+  struct bres_client *next, *prev;	/* Queue of waiting resolve jobs */
+  struct bres_server *rs;		/* Pointer to attached server */
+#endif
+  int q;				/* Query type (name or address) */
+  union {
+    struct in_addr addr;		/* Address to resolve */
+    char *name;				/* Name to resolve */
+  } u;
+  void (*func)(struct hostent */*h*/, void */*p*/); /* Handler function */
+  void *p;				/* Argument for handler function */
+} bres_client;
+
+/* --- Server maintained resolver blocks --- */
+
+typedef struct bres_server {
+  struct bres_server *next, *prev;	/* Doubly-linked list of servers */
+  pid_t kid;				/* Process id of server process */
+  int fd;				/* File descriptors */
+  struct bres_client *rc;		/* Pointer to attached client */
+  sel_timer t;				/* Timeout for idle servers */
+  sel_file f;				/* Read selector for server */
+} bres_server;
+
+/*----- Functions provided ------------------------------------------------*/
+
+/* --- @bres_abort@ --- *
+ *
+ * Arguments:	@bres_client *rc@ = pointer to client block
+ *
+ * Returns:	---
+ *
+ * Use:		Removes a queued job.
+ */
+
+extern void bres_abort(bres_client */*rc*/);
+
+/* --- @bres_byaddr@ --- *
+ *
+ * Arguments:	@bres_client *rc@ = pointer to client block
+ *		@struct in_addr addr@ = address to resolve
+ *		@void (*func)(struct hostent *h, void *p)@ = handler function
+ *		@void *p@ = argument for handler function
+ *
+ * Returns:	---
+ *
+ * Use:		Adds an address lookup job to the queue.  The job will be
+ *		processed when there's a spare resolver process to deal with
+ *		it.
+ */
+
+extern void bres_byaddr(bres_client */*rc*/, struct in_addr /*addr*/,
+			void (*/*func*/)(struct hostent */*h*/, void */*p*/),
+			void */*p*/);
+
+/* --- @bres_byname@ --- *
+ *
+ * Arguments:	@bres_client *rc@ = pointer to client block
+ *		@const char *name@ = name to resolve
+ *		@void (*func)(struct hostent *h, void *p)@ = handler function
+ *		@void *p@ = argument for handler function
+ *
+ * Returns:	---
+ *
+ * Use:		Adds a name lookup job to the queue.  The job will be
+ *		processed when there's a spare resolver process to deal with
+ *		it.
+ */
+
+extern void bres_byname(bres_client */*rc*/, const char */*name*/,
+			void (*/*func*/)(struct hostent */*h*/, void */*p*/),
+			void */*p*/);
+
+/* --- @bres_exec@ --- *
+ *
+ * Arguments:	@const char *file@ = file containing server code or null
+ *
+ * Returns:	---
+ *
+ * Use:		Makes `bres' use a standalone server rather than copies of
+ *		the current process.  This can reduce memory consumption for
+ *		large processes, at the expense of startup time (which
+ *		shouldn't be too bad anyway, because of the resolver design).
+ *		If the filename is null, a default set up at install time is
+ *		used.  It's probably a good idea to leave it alone.
+ */
+
+extern void bres_exec(const char */*file*/);
+
+/* --- @bres_init@ --- *
+ *
+ * Arguments:	@sel_state *s@ = pointer to select multiplexor
+ *
+ * Returns:	---
+ *
+ * Use:		Initializes the background resolver for use.
+ */
+
+extern void bres_init(sel_state */*s*/);
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+  }
+#endif
+
+#endif