package/libnl-tiny/src/handlers.c

   1 /*
   2  * lib/handlers.c       default netlink message handlers
   3  *
   4  *      This library is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU Lesser General Public
   6  *      License as published by the Free Software Foundation version 2.1
   7  *      of the License.
   8  *
   9  * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
  10  */
  11
  12 /**
  13  * @ingroup core
  14  * @defgroup cb Callbacks/Customization
  15  *
  16  * @details
  17  * @par 1) Setting up a callback set
  18  * @code
  19  * // Allocate a callback set and initialize it to the verbose default set
  20  * struct nl_cb *cb = nl_cb_alloc(NL_CB_VERBOSE);
  21  *
  22  * // Modify the set to call my_func() for all valid messages
  23  * nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, my_func, NULL);
  24  *
  25  * // Set the error message handler to the verbose default implementation
  26  * // and direct it to print all errors to the given file descriptor.
  27  * FILE *file = fopen(...);
  28  * nl_cb_err(cb, NL_CB_VERBOSE, NULL, file);
  29  * @endcode
  30  * @{
  31  */
  32
  33 #include <netlink-local.h>
  34 #include <netlink/netlink.h>
  35 #include <netlink/utils.h>
  36 #include <netlink/msg.h>
  37 #include <netlink/handlers.h>
  38
  39 /**
  40  * @name Callback Handle Management
  41  * @{
  42  */
  43
  44 /**
  45  * Allocate a new callback handle
  46  * @arg kind            callback kind to be used for initialization
  47  * @return Newly allocated callback handle or NULL
  48  */
  49 struct nl_cb *nl_cb_alloc(enum nl_cb_kind kind)
  50 {
  51         int i;
  52         struct nl_cb *cb;
  53
  54         if (kind < 0 || kind > NL_CB_KIND_MAX)
  55                 return NULL;
  56
  57         cb = calloc(1, sizeof(*cb));
  58         if (!cb)
  59                 return NULL;
  60
  61         cb->cb_refcnt = 1;
  62
  63         for (i = 0; i <= NL_CB_TYPE_MAX; i++)
  64                 nl_cb_set(cb, i, kind, NULL, NULL);
  65
  66         nl_cb_err(cb, kind, NULL, NULL);
  67
  68         return cb;
  69 }
  70
  71 /**
  72  * Clone an existing callback handle
  73  * @arg orig            original callback handle
  74  * @return Newly allocated callback handle being a duplicate of
  75  *         orig or NULL
  76  */
  77 struct nl_cb *nl_cb_clone(struct nl_cb *orig)
  78 {
  79         struct nl_cb *cb;
  80
  81         cb = nl_cb_alloc(NL_CB_DEFAULT);
  82         if (!cb)
  83                 return NULL;
  84
  85         memcpy(cb, orig, sizeof(*orig));
  86         cb->cb_refcnt = 1;
  87
  88         return cb;
  89 }
  90
  91 void nl_cb_put(struct nl_cb *cb)
  92 {
  93         if (!cb)
  94                 return;
  95
  96         cb->cb_refcnt--;
  97
  98         if (cb->cb_refcnt < 0)
  99                 BUG();
 100
 101         if (cb->cb_refcnt <= 0)
 102                 free(cb);
 103 }
 104
 105 /** @} */
 106
 107 /**
 108  * @name Callback Setup
 109  * @{
 110  */
 111
 112 /**
 113  * Set up a callback
 114  * @arg cb              callback set
 115  * @arg type            callback to modify
 116  * @arg kind            kind of implementation
 117  * @arg func            callback function (NL_CB_CUSTOM)
 118  * @arg arg             argument passed to callback
 119  *
 120  * @return 0 on success or a negative error code
 121  */
 122 int nl_cb_set(struct nl_cb *cb, enum nl_cb_type type, enum nl_cb_kind kind,
 123               nl_recvmsg_msg_cb_t func, void *arg)
 124 {
 125         if (type < 0 || type > NL_CB_TYPE_MAX)
 126                 return -NLE_RANGE;
 127
 128         if (kind < 0 || kind > NL_CB_KIND_MAX)
 129                 return -NLE_RANGE;
 130
 131         if (kind == NL_CB_CUSTOM) {
 132                 cb->cb_set[type] = func;
 133                 cb->cb_args[type] = arg;
 134         }
 135
 136         return 0;
 137 }
 138
 139 /**
 140  * Set up an error callback
 141  * @arg cb              callback set
 142  * @arg kind            kind of callback
 143  * @arg func            callback function
 144  * @arg arg             argument to be passed to callback function
 145  */
 146 int nl_cb_err(struct nl_cb *cb, enum nl_cb_kind kind,
 147               nl_recvmsg_err_cb_t func, void *arg)
 148 {
 149         if (kind < 0 || kind > NL_CB_KIND_MAX)
 150                 return -NLE_RANGE;
 151
 152         if (kind == NL_CB_CUSTOM) {
 153                 cb->cb_err = func;
 154                 cb->cb_err_arg = arg;
 155         }
 156
 157         return 0;
 158 }
 159
 160 /** @} */
 161
 162 /** @} */