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 #include <setjmp.h>
  14
  15 #include "nest/bird.h"
  16 #include "lib/lists.h"
  17 #include "lib/resource.h"
  18 #include "lib/socket.h"
  19 #include "nest/route.h"
  20 #include "nest/protocol.h"
  21 #include "nest/iface.h"
  22 #include "conf/conf.h"
  23 #include "filter/filter.h"
  24
  25 struct f_inst *autoexec_func = NULL;
  26
  27 #define runtime(x) do { \
  28     log( L_ERR, x ); \
  29     res.type = T_RETURN; \
  30     res.val.i = F_ERROR; \
  31     return res; \
  32   } while(0)
  33
  34 #define ARG(x,y) \
  35         x = interpret(what->y); \
  36         if (x.type == T_RETURN) \
  37                 return x;
  38
  39 #define ONEARG ARG(v1, arg1)
  40 #define TWOARGS ARG(v1, arg1) \
  41                 ARG(v2, arg2)
  42
  43 static struct f_val
  44 interpret(struct f_inst *what)
  45 {
  46   struct symbol *sym;
  47   struct f_val v1, v2, res;
  48
  49   res.type = T_VOID;
  50   if (!what)
  51     return res;
  52
  53   switch(what->code) {
  54   case ',':
  55     TWOARGS;
  56     break;
  57   case '+':
  58     TWOARGS;
  59     if (v1.type != v2.type)
  60       runtime( "Can not operate with values of incompatible types" );
  61
  62     switch (res.type = v1.type) {
  63     case T_VOID: runtime( "Can not operate with values of type void" );
  64     case T_INT: res.val.i = v1.val.i + v2.val.i; break;
  65     default: runtime( "Usage of unknown type" );
  66     }
  67     break;
  68   case '=':
  69     ARG(v2, arg2);
  70     sym = what->arg1;
  71     switch (res.type = v2.type) {
  72     case T_VOID: runtime( "Can not assign void values" );
  73     case T_INT:
  74       if (sym->class != SYM_VARIABLE_INT)
  75         runtime( "Variable of bad type" );
  76       sym->aux = v2.val.i;
  77       break;
  78     }
  79     break;
  80   case 'c':
  81     res.type = T_INT;
  82     res.val.i = (int) what->arg1;
  83     break;
  84   case 'i':
  85     res.type = T_INT;
  86     res.val.i = * ((int *) what->arg1);
  87     break;
  88   case 'p':
  89     ONEARG;
  90     printf( "Printing: " );
  91     switch (v1.type) {
  92     case T_VOID: printf( "(void)" ); break;
  93     case T_INT: printf( "%d", v1.val.i ); break;
  94     default: runtime( "Print of variable of unknown type" );
  95     }
  96     printf( "\n" );
  97     break;
  98   case '?':
  99     ONEARG;
 100     if (v1.type != T_INT)
 101       runtime( "If requires integer expression" );
 102     if (v1.val.i) {
 103       ARG(res,arg2);
 104     }
 105     break;
 106   case 'D':
 107     printf( "DEBUGGING PRINT\n" );
 108     break;
 109   case '0':
 110     printf( "No operation\n" );
 111     break;
 112   case 'd':
 113     printf( "Puts: %s\n", (char *) what->arg1 );
 114     break;
 115   case '!':
 116     switch ((int) what->arg1) {
 117     case F_QUITBIRD:
 118       die( "Filter asked me to die" );
 119     case F_ACCEPT:
 120       /* Should take care about turning ACCEPT into MODIFY */
 121     case F_ERROR:
 122     case F_REJECT:
 123       res.type = T_RETURN;
 124       res.val.i = (int) what->arg1;
 125       break;
 126     default:
 127       bug( "unknown return type: can not happen");
 128     }
 129     break;
 130   default:
 131     bug( "Unknown instruction %d (%c)", what->code, what->code & 0xff);
 132   }
 133   if (what->next)
 134     return interpret(what->next);
 135   return res;
 136 }
 137
 138 struct f_inst *
 139 f_new_inst(void)
 140 {
 141   struct f_inst * ret;
 142   ret = cfg_alloc(sizeof(struct f_inst));
 143   ret->code = 0;
 144   ret->arg1 = ret->arg2 = ret->next = NULL;
 145   return ret;
 146 }
 147
 148 int
 149 f_run(struct filter *filter, struct rte *rtein, struct rte **rteout)
 150 {
 151   struct f_inst *inst;
 152   struct f_val res;
 153   debug( "Running filter `%s'...", filter->name );
 154
 155   inst = filter->root;
 156   res = interpret(inst);
 157   if (res.type != T_RETURN)
 158     return F_ERROR;
 159   debug( "done (%d)\n", res.val.i );
 160   return res.val.i;
 161 }
 162
 163 void
 164 filters_postconfig(void)
 165 {
 166   if (autoexec_func)
 167     interpret(autoexec_func);
 168 }