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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];
uchar dport[2];
uchar seq[4];
uchar ack[4];
uchar flag[2];
uchar win[2];
uchar cksum[2];
uchar urg[2];
uchar opt[1];
};
typedef struct PseudoHdr{
uchar src[4];
uchar dst[4];
uchar zero;
uchar proto;
uchar length[2];
uchar hdrdata[1580];
} PseudoHdr;
enum
{
TCPLEN= 20
};
enum
{
Os,
Od,
Osd
};
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}
};
static Mux p_mux[] =
{
{"ninep", 17007, }, /* exportfs */
{"ninep", 564, }, /* 9fs */
{"ninep", 17005, }, /* ocpu */
{"ninep", 17010, }, /* ncpu */
{"ninep", 17013, }, /* cpu */
{0}
};
enum
{
EOLOPT = 0,
NOOPOPT = 1,
MSSOPT = 2,
MSS_LENGTH = 4, /* Mean segment size */
WSOPT = 3,
WS_LENGTH = 3, /* Bits to scale window size by */
};
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 tcp field or protocol: %s", f->s);
}
static int
p_filter(Filter *f, Msg *m)
{
Hdr *h;
if(m->pe - m->ps < TCPLEN)
return 0;
h = (Hdr*)m->ps;
m->ps += ((NetS(h->flag)>>10)&0x3f);
switch(f->subop){
case Os:
return NetS(h->sport) == f->ulv;
case Od:
return NetS(h->dport) == f->ulv;
case Osd:
return NetS(h->sport) == f->ulv || NetS(h->dport) == f->ulv;
}
return 0;
}
enum
{
URG = 0x20, /* Data marked urgent */
ACK = 0x10, /* Aknowledge is valid */
PSH = 0x08, /* Whole data pipe is pushed */
RST = 0x04, /* Reset connection */
SYN = 0x02, /* Pkt. is synchronise */
FIN = 0x01, /* Start close down */
};
static char*
flags(int f)
{
static char fl[20];
char *p;
p = fl;
if(f & URG)
*p++ = 'U';
if(f & ACK)
*p++ = 'A';
if(f & PSH)
*p++ = 'P';
if(f & RST)
*p++ = 'R';
if(f & SYN)
*p++ = 'S';
if(f & FIN)
*p++ = 'F';
*p = 0;
return fl;
}
static int
p_seprint(Msg *m)
{
Hdr *h;
int dport, sport;
int len, flag, optlen;
uchar *optr;
if(m->pe - m->ps < TCPLEN)
return -1;
h = (Hdr*)m->ps;
/* get tcp header length */
flag = NetS(h->flag);
len = (flag>>10)&~3;
flag &= 0x3ff;
m->ps += len;
/* next protocol */
dport = NetS(h->dport);
sport = NetS(h->sport);
demux(p_mux, sport, dport, m, &dump);
m->p = seprint(m->p, m->e, "s=%d d=%d seq=%lud ack=%lud fl=%s win=%d ck=%4.4ux",
NetS(h->sport), dport,
(ulong)NetL(h->seq), (ulong)NetL(h->ack),
flags(flag), NetS(h->win),
NetS(h->cksum));
/* tcp options */
len -= TCPLEN;
optr = h->opt;
while(len > 0) {
if(*optr == EOLOPT){
m->p = seprint(m->p, m->e, " opt=EOL");
break;
}
if(*optr == NOOPOPT) {
m->p = seprint(m->p, m->e, " opt=NOOP");
len--;
optr++;
continue;
}
optlen = optr[1];
if(optlen < 2 || optlen > len)
break;
switch(*optr) {
case MSSOPT:
m->p = seprint(m->p, m->e, " opt%d=(mss %ud)", optlen, nhgets(optr+2));
break;
case WSOPT:
m->p = seprint(m->p, m->e, " opt%d=(wscale %ud)", optlen, *(optr+2));
break;
default:
m->p = seprint(m->p, m->e, " opt%d=(%ud %.*H)", optlen, *optr, optlen-2,optr+2);
}
len -= optlen;
optr += optlen;
}
if(Cflag){
/* editing in progress by ehg */
}
return 0;
}
Proto tcp =
{
"tcp",
p_compile,
p_filter,
p_seprint,
p_mux,
"%lud",
p_fields,
defaultframer
};
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