new goodies

src/cmd/ip/snoopy/udp.c

@@ -0,0 +1,131 @@
+#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[] =
+{
+	{"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,
+	p_fields,
+	defaultframer,
+};