Subversion Repositories planix.SVN

#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[] =
{
        {"dns",         53, },
        {"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(tcp.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)
{
        int dport, sport, len, flag, optlen;
        uchar *optr;
        Hdr *h;

        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;
        }
        return 0;
}

Proto tcp =
{
        "tcp",
        p_compile,
        p_filter,
        p_seprint,
        p_mux,
        "%lud",
        p_fields,
        defaultframer,
};