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   hrd[2];
        uchar   pro[2];
        uchar   hln;
        uchar   pln;
        uchar   op[2];
        uchar   sha[6];
        uchar   spa[4];
        uchar   tha[6];
        uchar   tpa[4];
};

enum
{
        ARPLEN= 28,
};

enum
{
        Ospa,
        Otpa,
        Ostpa,
        Osha,
        Otha,
        Ostha,
        Opa,
};

static Field p_fields[] = 
{
        {"spa",         Fv4ip,  Ospa,   "protocol source",      } ,
        {"tpa",         Fv4ip,  Otpa,   "protocol target",      } ,
        {"a",           Fv4ip,  Ostpa,  "protocol source/target",       } ,
        {"sha",         Fba,    Osha,   "hardware source",      } ,
        {"tha",         Fba,    Otha,   "hardware target",      } ,
        {"ah",          Fba,    Ostha,  "hardware source/target",       } ,
        {0}
};

static void
p_compile(Filter *f)
{
        if(f->op == '='){
                compile_cmp(arp.name, f, p_fields);
                return;
        }
        sysfatal("unknown arp field: %s", f->s);
}

static int
p_filter(Filter *f, Msg *m)
{
        Hdr *h;

        if(m->pe - m->ps < ARPLEN)
                return 0;

        h = (Hdr*)m->ps;
        m->ps += ARPLEN;

        switch(f->subop){
        case Ospa:
                return h->pln == 4 && NetL(h->spa) == f->ulv;
        case Otpa:
                return h->pln == 4 && NetL(h->tpa) == f->ulv;
        case Ostpa:
                return h->pln == 4 && (NetL(h->tpa) == f->ulv ||
                        NetL(h->spa) == f->ulv);
        case Osha:
                return memcmp(h->sha, f->a, h->hln) == 0;
        case Otha:
                return memcmp(h->tha, f->a, h->hln) == 0;
        case Ostha:
                return memcmp(h->sha, f->a, h->hln)==0
                        ||memcmp(h->tha, f->a, h->hln)==0;
        }
        return 0;
}

static int
p_seprint(Msg *m)
{
        Hdr *h;

        if(m->pe - m->ps < ARPLEN)
                return -1;

        h = (Hdr*)m->ps;
        m->ps += ARPLEN;

        /* no next protocol */
        m->pr = nil;

        m->p = seprint(m->p, m->e, "op=%1d len=%1d/%1d spa=%V sha=%E tpa=%V tha=%E",
                        NetS(h->op), h->pln, h->hln,
                        h->spa, h->sha, h->tpa, h->tha);
        return 0;
}

Proto arp =
{
        "arp",
        p_compile,
        p_filter,
        p_seprint,
        nil,
        nil,
        p_fields,
        defaultframer,
};

Proto rarp =
{
        "rarp",
        p_compile,
        p_filter,
        p_seprint,
        nil,
        nil,
        p_fields,
        defaultframer,
};