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#include <u.h>
#include <libc.h>
#include <ip.h>
#include "dat.h"
#include "protos.h"
typedef struct Hdr Hdr;
struct Hdr
{
uchar sport[2]; /* Source port */
uchar dport[2]; /* Destination port */
uchar len[2]; /* data length */
uchar cksum[2]; /* Checksum */
};
enum
{
UDPLEN= 8
};
enum
{
Os,
Od,
Osd,
Osetport
};
static Field p_fields[] =
{
{"s", Fnum, Os, "source port", } ,
{"d", Fnum, Od, "dest port", } ,
{"a", Fnum, Osd, "source/dest port", } ,
{"sd", Fnum, Osd, "source/dest port", } ,
{0}
};
#define ANYPORT ~0UL
static Mux p_mux[] =
{
{"bootp", 67, },
{"ninep", 6346, }, /* tvs */
{"dns", 53 },
{"rtp", ANYPORT, },
{"rtcp", ANYPORT, },
{0}
};
/* default next protocol, can be changed by p_filter, reset by p_compile */
static Proto *defproto = &dump;
static void
p_compile(Filter *f)
{
Mux *m;
if(f->op == '='){
compile_cmp(udp.name, f, p_fields);
return;
}
for(m = p_mux; m->name != nil; m++)
if(strcmp(f->s, m->name) == 0){
f->pr = m->pr;
f->ulv = m->val;
f->subop = Osd;
return;
}
sysfatal("unknown udp field or protocol: %s", f->s);
}
static int
p_filter(Filter *f, Msg *m)
{
Hdr *h;
if(m->pe - m->ps < UDPLEN)
return 0;
h = (Hdr*)m->ps;
m->ps += UDPLEN;
switch(f->subop){
case Os:
return NetS(h->sport) == f->ulv;
case Od:
return NetS(h->dport) == f->ulv;
case Osd:
if(f->ulv == ANYPORT){
defproto = f->pr;
return 1;
}
return NetS(h->sport) == f->ulv || NetS(h->dport) == f->ulv;
}
return 0;
}
static int
p_seprint(Msg *m)
{
Hdr *h;
int dport, sport;
if(m->pe - m->ps < UDPLEN)
return -1;
h = (Hdr*)m->ps;
m->ps += UDPLEN;
/* next protocol */
sport = NetS(h->sport);
dport = NetS(h->dport);
demux(p_mux, sport, dport, m, defproto);
defproto = &dump;
m->p = seprint(m->p, m->e, "s=%d d=%d ck=%4.4ux ln=%4d",
NetS(h->sport), dport,
NetS(h->cksum), NetS(h->len));
return 0;
}
Proto udp =
{
"udp",
p_compile,
p_filter,
p_seprint,
p_mux,
"%lud",
p_fields,
defaultframer
};
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