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 hrd[2];
11 uchar pro[2];
12 uchar hln;
13 uchar pln;
14 uchar op[2];
15 uchar sha[6];
16 uchar spa[4];
17 uchar tha[6];
18 uchar tpa[4];
19 };
20
21 enum
22 {
23 ARPLEN= 28,
24 };
25
26 enum
27 {
28 Ospa,
29 Otpa,
30 Ostpa,
31 Osha,
32 Otha,
33 Ostha,
34 Opa,
35 };
36
37 static Field p_fields[] =
38 {
39 {"spa", Fv4ip, Ospa, "protocol source", } ,
40 {"tpa", Fv4ip, Otpa, "protocol target", } ,
41 {"a", Fv4ip, Ostpa, "protocol source/target", } ,
42 {"sha", Fba, Osha, "hardware source", } ,
43 {"tha", Fba, Otha, "hardware target", } ,
44 {"ah", Fba, Ostha, "hardware source/target", } ,
45 {0}
46 };
47
48 static void
p_compile(Filter * f)49 p_compile(Filter *f)
50 {
51 if(f->op == '='){
52 compile_cmp(arp.name, f, p_fields);
53 return;
54 }
55 sysfatal("unknown arp field: %s", f->s);
56 }
57
58 static int
p_filter(Filter * f,Msg * m)59 p_filter(Filter *f, Msg *m)
60 {
61 Hdr *h;
62
63 if(m->pe - m->ps < ARPLEN)
64 return 0;
65
66 h = (Hdr*)m->ps;
67 m->ps += ARPLEN;
68
69 switch(f->subop){
70 case Ospa:
71 return h->pln == 4 && NetL(h->spa) == f->ulv;
72 case Otpa:
73 return h->pln == 4 && NetL(h->tpa) == f->ulv;
74 case Ostpa:
75 return h->pln == 4 && (NetL(h->tpa) == f->ulv ||
76 NetL(h->spa) == f->ulv);
77 case Osha:
78 return memcmp(h->sha, f->a, h->hln) == 0;
79 case Otha:
80 return memcmp(h->tha, f->a, h->hln) == 0;
81 case Ostha:
82 return memcmp(h->sha, f->a, h->hln)==0
83 ||memcmp(h->tha, f->a, h->hln)==0;
84 }
85 return 0;
86 }
87
88 static int
p_seprint(Msg * m)89 p_seprint(Msg *m)
90 {
91 Hdr *h;
92
93 if(m->pe - m->ps < ARPLEN)
94 return -1;
95
96 h = (Hdr*)m->ps;
97 m->ps += ARPLEN;
98
99 /* no next protocol */
100 m->pr = nil;
101
102 m->p = seprint(m->p, m->e, "op=%1d len=%1d/%1d spa=%V sha=%E tpa=%V tha=%E",
103 NetS(h->op), h->pln, h->hln,
104 h->spa, h->sha, h->tpa, h->tha);
105 return 0;
106 }
107
108 Proto arp =
109 {
110 "arp",
111 p_compile,
112 p_filter,
113 p_seprint,
114 nil,
115 nil,
116 p_fields,
117 defaultframer,
118 };
119
120 Proto rarp =
121 {
122 "rarp",
123 p_compile,
124 p_filter,
125 p_seprint,
126 nil,
127 nil,
128 p_fields,
129 defaultframer,
130 };
131