sys/src/cmd/ip/snoopy/eapol.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <ip.h>
   4 #include "dat.h"
   5 #include "protos.h"
   6
   7 typedef struct Hdr      Hdr;
   8 struct Hdr
   9 {
  10         uchar   vi;             /* version */
  11         uchar   type;
  12         uchar   len[2]; /* length of data following this header */
  13 };
  14
  15 enum
  16 {
  17         EAPOLHDR=       4,              /* sizeof(Hdr) */
  18
  19         /* eapol types */
  20         Eap = 0,
  21         Start,
  22         Logoff,
  23         Key,
  24         AsfAlert,
  25 };
  26
  27 enum
  28 {
  29         Ot,     /* type */
  30 };
  31
  32 static Mux p_mux[] =
  33 {
  34         { "eap", Eap, },
  35         { "eapol_start", Start, },
  36         { "eapol_logoff", Logoff, },
  37         { "eapol_key", Key, },
  38         { "asf_alert", AsfAlert, },
  39         { 0 }
  40 };
  41
  42 static void
  43 p_compile(Filter *f)
  44 {
  45         Mux *m;
  46
  47         for(m = p_mux; m->name != nil; m++)
  48                 if(strcmp(f->s, m->name) == 0){
  49                         f->pr = m->pr;
  50                         f->ulv = m->val;
  51                         f->subop = Ot;
  52                         return;
  53                 }
  54         sysfatal("unknown eapol field or type: %s", f->s);
  55 }
  56
  57 static int
  58 p_filter(Filter *f, Msg *m)
  59 {
  60         Hdr *h;
  61
  62         if(m->pe - m->ps < EAPOLHDR)
  63                 return 0;
  64
  65         h = (Hdr*)m->ps;
  66
  67         /* len does not include header */
  68         m->ps += EAPOLHDR;
  69
  70         switch(f->subop){
  71         case Ot:
  72                 return h->type == f->ulv;
  73         }
  74         return 0;
  75 }
  76
  77 static char*
  78 op(int i)
  79 {
  80         static char x[20];
  81
  82         switch(i){
  83         case Eap:
  84                 return "Eap";
  85         case Start:
  86                 return "Start";
  87         case Logoff:
  88                 return "Logoff";
  89         case Key:
  90                 return "Key";
  91         case AsfAlert:
  92                 return "AsfAlert";
  93         default:
  94                 sprint(x, "%1d", i);
  95                 return x;
  96         }
  97 }
  98
  99 static int
 100 p_seprint(Msg *m)
 101 {
 102         Hdr *h;
 103         int len;
 104
 105         if(m->pe - m->ps < EAPOLHDR)
 106                 return -1;
 107
 108         h = (Hdr*)m->ps;
 109
 110         /* len does not include header */
 111         m->ps += EAPOLHDR;
 112
 113         /* truncate the message if there's extra */
 114         len = NetS(h->len);
 115         if(m->ps + len < m->pe)
 116                 m->pe = m->ps + len;
 117         else if(m->ps+len > m->pe)
 118                 return -1;
 119
 120         /* next protocol  depending on type*/
 121         demux(p_mux, h->type, h->type, m, &dump);
 122
 123         m->p = seprint(m->p, m->e, "type=%s version=%1d datalen=%1d",
 124                         op(h->type), h->vi, len);
 125         return 0;
 126 }
 127
 128 Proto eapol =
 129 {
 130         "eapol",
 131         p_compile,
 132         p_filter,
 133         p_seprint,
 134         p_mux,
 135         "%lud",
 136         nil,
 137         defaultframer,
 138 };