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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];
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	uchar	dport[2];
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	uchar	seq[4];
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	uchar	ack[4];
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	uchar	flag[2];
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	uchar	win[2];
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	uchar	cksum[2];
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	uchar	urg[2];
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	uchar	opt[1];
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};
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typedef struct PseudoHdr{
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	uchar	src[4];
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	uchar	dst[4];
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	uchar	zero;
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	uchar	proto;
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	uchar	length[2];
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	uchar	hdrdata[1580];
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} PseudoHdr;
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enum
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{
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	TCPLEN= 20,
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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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};
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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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static Mux p_mux[] =
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{
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	{"dns",		53, },
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	{"ninep",	17007, },	/* exportfs */
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	{"ninep",	564, },		/* 9fs */
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	{"ninep",	17005, },	/* ocpu */
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	{"ninep",	17010, },	/* ncpu */
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	{"ninep",	17013, },	/* cpu */
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	{0},
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};
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enum
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{
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	EOLOPT		= 0,
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	NOOPOPT		= 1,
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	MSSOPT		= 2,
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	MSS_LENGTH	= 4,		/* Mean segment size */
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	WSOPT		= 3,
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	WS_LENGTH	= 3,		/* Bits to scale window size by */
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};
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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(tcp.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 tcp 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 < TCPLEN)
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		return 0;
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	h = (Hdr*)m->ps;
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	m->ps += (NetS(h->flag)>>10) & 0x3f;
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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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		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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enum
114 
{
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	URG		= 0x20,		/* Data marked urgent */
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	ACK		= 0x10,		/* Aknowledge is valid */
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	PSH		= 0x08,		/* Whole data pipe is pushed */
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	RST		= 0x04,		/* Reset connection */
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	SYN		= 0x02,		/* Pkt. is synchronise */
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	FIN		= 0x01,		/* Start close down */
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};
122 
 
123 
static char*
124 
flags(int f)
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{
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	static char fl[20];
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	char *p;
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	p = fl;
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	if(f & URG)
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		*p++ = 'U';
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	if(f & ACK)
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		*p++ = 'A';
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	if(f & PSH)
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		*p++ = 'P';
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	if(f & RST)
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		*p++ = 'R';
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	if(f & SYN)
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		*p++ = 'S';
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	if(f & FIN)
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		*p++ = 'F';
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	*p = 0;
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	return fl;
144 
}
145 
 
146 
 
147 
static int
148 
p_seprint(Msg *m)
149 
{
150 
	int dport, sport, len, flag, optlen;
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	uchar *optr;
152 
	Hdr *h;
153 
 
154 
	if(m->pe - m->ps < TCPLEN)
155 
		return -1;
156 
	h = (Hdr*)m->ps;
157 
 
158 
	/* get tcp header length */
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	flag = NetS(h->flag);
160 
	len = (flag>>10) & ~3;
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	flag &= 0x3ff;
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	m->ps += len;
163 
 
164 
	/* next protocol */
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	dport = NetS(h->dport);
166 
	sport = NetS(h->sport);
167 
	demux(p_mux, sport, dport, m, &dump);
168 
 
169 
	m->p = seprint(m->p, m->e, "s=%d d=%d seq=%lud ack=%lud fl=%s win=%d ck=%4.4ux",
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			NetS(h->sport), dport,
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			(ulong)NetL(h->seq), (ulong)NetL(h->ack),
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			flags(flag), NetS(h->win),
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			NetS(h->cksum));
174 
 
175 
	/* tcp options */
176 
	len -= TCPLEN;
177 
	optr = h->opt;
178 
	while(len > 0) {
179 
		if(*optr == EOLOPT){
180 
			m->p = seprint(m->p, m->e, " opt=EOL");
181 
			break;
182 
		}
183 
		if(*optr == NOOPOPT) {
184 
			m->p = seprint(m->p, m->e, " opt=NOOP");
185 
			len--;
186 
			optr++;
187 
			continue;
188 
		}
189 
		optlen = optr[1];
190 
		if(optlen < 2 || optlen > len)
191 
			break;
192 
		switch(*optr) {
193 
		case MSSOPT:
194 
			m->p = seprint(m->p, m->e, " opt%d=(mss %ud)",
195 
				optlen, nhgets(optr+2));
196 
			break;
197 
		case WSOPT:
198 
			m->p = seprint(m->p, m->e, " opt%d=(wscale %ud)",
199 
				optlen, *(optr+2));
200 
			break;
201 
		default:
202 
			m->p = seprint(m->p, m->e, " opt%d=(%ud %.*H)",
203 
				optlen, *optr, optlen-2, optr+2);
204 
		}
205 
		len -= optlen;
206 
		optr += optlen;
207 
	}
208 
	return 0;
209 
}
210 
 
211 
Proto tcp =
212 
{
213 
	"tcp",
214 
	p_compile,
215 
	p_filter,
216 
	p_seprint,
217 
	p_mux,
218 
	"%lud",
219 
	p_fields,
220 
	defaultframer,
221 
};