1 /*
2  * SNAP.
3  */
4 
5 #include <u.h>
6 #include <libc.h>
7 #include <ip.h>
8 #include "dat.h"
9 #include "protos.h"
10 
11 enum
12 {
13 	Oorg,
14 	Oet,
15 
16 	OuiEther = 0,
17 	OuiCisco = 0xc,
18 	OuiCisco90 = 0xf8,
19 	OuiRfc2684 = 0x80c2,
20 	OuiAppletalk = 0x80007,
21 };
22 
23 static Mux p_mux[] =
24 {
25 	{"ip",		0x0800,	} ,
26 	{"arp",		0x0806,	} ,
27 	{"rarp",	0x0806,	} ,
28 	{"ip6", 	0x86dd, } ,
29 	{"pppoe_disc",	0x8863, },
30 	{"pppoe_sess",	0x8864, },
31 	{"eapol",	0x888e, },
32 	{ 0 }
33 };
34 
35 typedef struct Hdr Hdr;
36 struct Hdr
37 {
38 	uchar org[3];
39 	uchar et[2];
40 };
41 
42 static Field p_fields[] =
43 {
44 	{ "org",	Fnum,	Oorg,	"org" },
45 	{ "et",	Fnum,	Oet,	"et" },
46 	{ 0 }
47 };
48 
49 static void
50 p_compile(Filter *f)
51 {
52 	Mux *m;
53 
54 	if(f->op == '='){
55 		compile_cmp(snap.name, f, p_fields);
56 		return;
57 	}
58 	for(m = p_mux; m->name != nil; m++){
59 		if(strcmp(f->s, m->name) == 0){
60 			f->pr = m->pr;
61 			f->ulv = m->val;
62 			f->subop = Oet;
63 			return;
64 		}
65 	}
66 	sysfatal("unknown snap field or protocol: %s", f->s);
67 }
68 
69 static int
70 p_filter(Filter *f, Msg *m)
71 {
72 	Hdr *h;
73 
74 	if(m->pe - m->ps < sizeof(Hdr))
75 		return 0;
76 	h = (Hdr*)m->ps;
77 	m->ps += 5;
78 	switch(f->subop){
79 	case Oorg:
80 		return f->ulv == Net3(h->org);
81 	case Oet:
82 		return f->ulv == NetS(h->et);
83 	}
84 	return 0;
85 }
86 
87 static int
88 p_seprint(Msg *m)
89 {
90 	Hdr *h;
91 
92 	if(m->pe - m->ps < sizeof(Hdr))
93 		return 0;
94 	h = (Hdr*)m->ps;
95 	m->ps += 5;
96 	demux(p_mux, NetS(h->et), NetS(h->et), m, &dump);
97 
98 	m->p = seprint(m->p, m->e, "org=%06x et=%04x", Net3(h->org), NetS(h->et));
99 	return 0;
100 }
101 
102 Proto snap =
103 {
104 	"snap",
105 	p_compile,
106 	p_filter,
107 	p_seprint,
108 	p_mux,
109 	nil,
110 	nil,
111 	defaultframer
112 };