src/conftest/hooks/set_length.c

   1 /*
   2  * Copyright (C) 2010 Martin Willi
   3  * Copyright (C) 2010 revosec AG
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * for more details.
  14  */
  15
  16 #include "hook.h"
  17
  18 typedef struct private_set_length_t private_set_length_t;
  19
  20 /**
  21  * Private data of an set_length_t object.
  22  */
  23 struct private_set_length_t {
  24
  25         /**
  26          * Implements the hook_t interface.
  27          */
  28         hook_t hook;
  29
  30         /**
  31          * Alter requests or responses?
  32          */
  33         bool req;
  34
  35         /**
  36          * ID of message to alter.
  37          */
  38         int id;
  39
  40         /**
  41          * Payload type
  42          */
  43         char *type;
  44
  45         /**
  46          * Difference to correct length
  47          */
  48         int diff;
  49 };
  50
  51 METHOD(listener_t, message, bool,
  52         private_set_length_t *this, ike_sa_t *ike_sa, message_t *message,
  53         bool incoming)
  54 {
  55         if (!incoming &&
  56                 message->get_request(message) == this->req &&
  57                 message->get_message_id(message) == this->id)
  58         {
  59                 payload_t *payload;
  60                 enumerator_t *enumerator;
  61                 payload_type_t type;
  62
  63                 type = atoi(this->type);
  64                 if (!type)
  65                 {
  66                         type = enum_from_name(payload_type_short_names, this->type);
  67                         if (type == -1)
  68                         {
  69                                 DBG1(DBG_CFG, "unknown payload: '%s', skipped", this->type);
  70                                 return TRUE;
  71                         }
  72                 }
  73                 enumerator = message->create_payload_enumerator(message);
  74                 while (enumerator->enumerate(enumerator, &payload))
  75                 {
  76                         if (type == payload->get_type(payload))
  77                         {
  78                                 encoding_rule_t *rules;
  79                                 u_int16_t *len;
  80                                 int i, count;
  81
  82                                 count = payload->get_encoding_rules(payload, &rules);
  83                                 for (i = 0; i < count; i++)
  84                                 {
  85                                         if (rules[i].type == PAYLOAD_LENGTH)
  86                                         {
  87                                                 len = (u_int16_t*)(((void*)payload) + rules[i].offset);
  88                                                 DBG1(DBG_CFG, "adjusting length of %N payload "
  89                                                          "from %d to %d", payload_type_short_names, type,
  90                                                          *len, *len + this->diff);
  91                                                 *len = *len + this->diff;
  92                                         }
  93                                 }
  94                         }
  95                 }
  96                 enumerator->destroy(enumerator);
  97         }
  98         return TRUE;
  99 }
 100
 101 METHOD(hook_t, destroy, void,
 102         private_set_length_t *this)
 103 {
 104         free(this);
 105 }
 106
 107 /**
 108  * Create the IKE_AUTH fill hook
 109  */
 110 hook_t *set_length_hook_create(char *name)
 111 {
 112         private_set_length_t *this;
 113
 114         INIT(this,
 115                 .hook = {
 116                         .listener = {
 117                                 .message = _message,
 118                         },
 119                         .destroy = _destroy,
 120                 },
 121                 .req = conftest->test->get_bool(conftest->test,
 122                                                                                 "hooks.%s.request", TRUE, name),
 123                 .id = conftest->test->get_int(conftest->test,
 124                                                                                 "hooks.%s.id", 0, name),
 125                 .type = conftest->test->get_str(conftest->test,
 126                                                                                 "hooks.%s.type", "", name),
 127                 .diff = conftest->test->get_int(conftest->test,
 128                                                                                 "hooks.%s.diff", 0, name),
 129         );
 130
 131         return &this->hook;
 132 }