filter/f-util.c

   1 /*
   2  *      Filters: utility functions
   3  *
   4  *      Copyright 1998 Pavel Machek <pavel@ucw.cz>
   5  *
   6  *      Can be freely distributed and used under the terms of the GNU GPL.
   7  */
   8
   9 #include <stdio.h>
  10 #include <fcntl.h>
  11 #include <unistd.h>
  12 #include <sys/signal.h>
  13
  14 #include "nest/bird.h"
  15 #include "lib/lists.h"
  16 #include "lib/resource.h"
  17 #include "lib/socket.h"
  18 #include "nest/route.h"
  19 #include "nest/protocol.h"
  20 #include "nest/iface.h"
  21 #include "conf/conf.h"
  22 #include "filter/filter.h"
  23
  24 struct f_inst *last_func = NULL;
  25
  26 #define runtime die
  27
  28 static struct f_val
  29 interpret(struct f_inst *what)
  30 {
  31   struct symbol *sym;
  32   struct f_val v1, v2, res;
  33
  34   res.type = T_VOID;
  35   if (!what)
  36     return res;
  37
  38   switch(what->code) {
  39   case ',':
  40     interpret(what->arg1);
  41     interpret(what->arg2);
  42     break;
  43   case '+':
  44     v1 = interpret(what->arg1);
  45     v2 = interpret(what->arg2);
  46     if (v1.type != v2.type)
  47       runtime( "Can not operate with values of incompatible types" );
  48
  49     switch (res.type = v1.type) {
  50     case T_VOID: runtime( "Can not operate with values of type void" );
  51     case T_INT: res.val.i = v1.val.i + v2.val.i; break;
  52     default: runtime( "Usage of unknown type" );
  53     }
  54     break;
  55   case '=':
  56     v1 = interpret(what->arg2);
  57     sym = what->arg1;
  58     switch (res.type = v1.type) {
  59     case T_VOID: runtime( "Can not assign void values" );
  60     case T_INT:
  61       if (sym->class != SYM_VARIABLE_INT)
  62         runtime( "Variable of bad type" );
  63       sym->aux = v1.val.i;
  64       break;
  65     }
  66     break;
  67   case 'c':
  68     res.type = T_INT;
  69     res.val.i = (int) what->arg1;
  70     break;
  71   case 'i':
  72     res.type = T_INT;
  73     res.val.i = * ((int *) what->arg1);
  74     break;
  75   case 'p':
  76     v1 = interpret(what->arg1);
  77     printf( "Printing: " );
  78     switch (v1.type) {
  79     case T_VOID: printf( "(void)" ); break;
  80     case T_INT: printf( "%d", v1.val.i ); break;
  81     default: runtime( "Print of variable of unknown type" );
  82     }
  83     printf( "\n" );
  84     break;
  85   case '?':
  86     v1 = interpret(what->arg1);
  87     if (v1.type != T_INT)
  88       runtime( "If requires integer expression" );
  89     if (v1.val.i)
  90       res = interpret(what->arg2);
  91     break;
  92   case 'D':
  93     printf( "DEBUGGING PRINT\n" );
  94     break;
  95   case '0':
  96     printf( "No operation\n" );
  97     break;
  98   case 'd':
  99     printf( "Puts: %s\n", what->arg1 );
 100     break;
 101   case '!':
 102     die( "Filter asked me to die" );
 103   default:
 104     die( "Unknown insruction %d(%c)", what->code, what->code & 0xff);
 105   }
 106   if (what->next)
 107     return interpret(what->next);
 108   return res;
 109 }
 110
 111 void
 112 filters_postconfig(void)
 113 {
 114   if (!last_func)
 115     printf( "No function defined\n" );
 116   else {
 117     interpret(last_func);
 118   }
 119 }
 120
 121 struct f_inst *
 122 f_new_inst(void)
 123 {
 124   struct f_inst * ret;
 125   ret = cfg_alloc(sizeof(struct f_inst));
 126   ret->code = 0;
 127   ret->arg1 = ret->arg2 = ret->next = NULL;
 128   return ret;
 129 }
 130
 131 int
 132 f_run(struct symbol *filter, struct rte *rtein, struct rte **rteout)
 133 {
 134   struct f_inst *inst;
 135   debug( "Running filter `%s'...", filter->name );
 136
 137   inst = filter->def;
 138   interpret(inst);
 139   debug( "done\n" );
 140   return F_ACCEPT;
 141 }