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