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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]; /* Source port */
- uchar dport[2]; /* Destination port */
- uchar len[2]; /* data length */
- uchar cksum[2]; /* Checksum */
- };
- enum
- {
- UDPLEN= 8,
- };
- enum
- {
- Os,
- Od,
- Osd,
- Osetport,
- };
- 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}
- };
- #define ANYPORT ~0UL
- static Mux p_mux[] =
- {
- {"dns", 53, },
- {"bootp", 67, },
- {"ninep", 6346, }, /* tvs */
- {"rtp", ANYPORT, },
- {"rtcp", ANYPORT, },
- {0},
- };
- /* default next protocol, can be changed by p_filter, reset by p_compile */
- static Proto *defproto = &dump;
- 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 udp field or protocol: %s", f->s);
- }
- static int
- p_filter(Filter *f, Msg *m)
- {
- Hdr *h;
- if(m->pe - m->ps < UDPLEN)
- return 0;
- h = (Hdr*)m->ps;
- m->ps += UDPLEN;
- switch(f->subop){
- case Os:
- return NetS(h->sport) == f->ulv;
- case Od:
- return NetS(h->dport) == f->ulv;
- case Osd:
- if(f->ulv == ANYPORT){
- defproto = f->pr;
- return 1;
- }
- return NetS(h->sport) == f->ulv || NetS(h->dport) == f->ulv;
- }
- return 0;
- }
- static int
- p_seprint(Msg *m)
- {
- Hdr *h;
- int dport, sport;
- if(m->pe - m->ps < UDPLEN)
- return -1;
- h = (Hdr*)m->ps;
- m->ps += UDPLEN;
- /* next protocol */
- sport = NetS(h->sport);
- dport = NetS(h->dport);
- demux(p_mux, sport, dport, m, defproto);
- defproto = &dump;
- m->p = seprint(m->p, m->e, "s=%d d=%d ck=%4.4ux ln=%4d",
- NetS(h->sport), dport,
- NetS(h->cksum), NetS(h->len));
- return 0;
- }
- Proto udp =
- {
- "udp",
- p_compile,
- p_filter,
- p_seprint,
- p_mux,
- "%lud",
- p_fields,
- defaultframer,
- };
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