new goodies

src/cmd/ip/snoopy/icmp.c

@@ -0,0 +1,196 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+#include "dat.h"
+#include "protos.h"
+
+typedef struct Hdr	Hdr;
+struct Hdr
+{	uchar	type;
+	uchar	code;
+	uchar	cksum[2];	/* Checksum */
+	uchar	data[1];
+};
+
+enum
+{
+	ICMPLEN=	4,
+};
+
+enum
+{
+	Ot,	/* type */
+	Op,	/* next protocol */
+};
+
+static Field p_fields[] = 
+{
+	{"t",		Fnum,	Ot,	"type",	} ,
+	{0}
+};
+
+enum
+{
+	EchoRep=	0,
+	Unreachable=	3,
+	SrcQuench=	4,
+	Redirect=	5,
+	EchoReq=	8,
+	TimeExceed=	11,
+	ParamProb=	12,
+	TSreq=		13,
+	TSrep=		14,
+	InfoReq=	15,
+	InfoRep=	16,
+};
+
+static Mux p_mux[] =
+{
+	{"ip",	Unreachable, },
+	{"ip",	SrcQuench, },
+	{"ip",	Redirect, },
+	{"ip",	TimeExceed, },
+	{"ip",	ParamProb, },
+	{0},
+};
+
+char *icmpmsg[236] =
+{
+[EchoRep]	"EchoRep",
+[Unreachable]	"Unreachable",
+[SrcQuench]	"SrcQuench",
+[Redirect]	"Redirect",
+[EchoReq]	"EchoReq",
+[TimeExceed]	"TimeExceed",
+[ParamProb]	"ParamProb",
+[TSreq]		"TSreq",
+[TSrep]		"TSrep",
+[InfoReq]	"InfoReq",
+[InfoRep]	"InfoRep",
+};
+
+static void
+p_compile(Filter *f)
+{
+	if(f->op == '='){
+		compile_cmp(udp.name, f, p_fields);
+		return;
+	}
+	if(strcmp(f->s, "ip") == 0){
+		f->pr = p_mux->pr;
+		f->subop = Op;
+		return;
+	}
+	sysfatal("unknown icmp field or protocol: %s", f->s);
+}
+
+static int
+p_filter(Filter *f, Msg *m)
+{
+	Hdr *h;
+
+	if(m->pe - m->ps < ICMPLEN)
+		return 0;
+
+	h = (Hdr*)m->ps;
+	m->ps += ICMPLEN;
+
+	switch(f->subop){
+	case Ot:
+		if(h->type == f->ulv)
+			return 1;
+		break;
+	case Op:
+		switch(h->type){
+		case Unreachable:
+		case TimeExceed:
+		case SrcQuench:
+		case Redirect:
+		case ParamProb:
+			m->ps += 4;
+			return 1;
+		}
+	}
+	return 0;
+}
+
+static int
+p_seprint(Msg *m)
+{
+	Hdr *h;
+	char *tn;
+	char *p = m->p;
+	char *e = m->e;
+	ushort cksum2, cksum;
+
+	h = (Hdr*)m->ps;
+	m->ps += ICMPLEN;
+	m->pr = &dump;
+
+	if(m->pe - m->ps < ICMPLEN)
+		return -1;
+
+	tn = icmpmsg[h->type];
+	if(tn == nil)
+		p = seprint(p, e, "t=%ud c=%d ck=%4.4ux", h->type,
+			h->code, (ushort)NetS(h->cksum));
+	else
+		p = seprint(p, e, "t=%s c=%d ck=%4.4ux", tn,
+			h->code, (ushort)NetS(h->cksum));
+	if(Cflag){
+		cksum = NetS(h->cksum);
+		h->cksum[0] = 0;
+		h->cksum[1] = 0;
+		cksum2 = ~ptclbsum((uchar*)h, m->pe - m->ps + ICMPLEN) & 0xffff;
+		if(cksum != cksum2)
+			p = seprint(p,e, " !ck=%4.4ux", cksum2);
+	}
+	switch(h->type){
+	case EchoRep:
+	case EchoReq:
+		m->ps += 4;
+		p = seprint(p, e, " id=%ux seq=%ux",
+			NetS(h->data), NetS(h->data+2));
+		break;
+	case TSreq:
+	case TSrep:
+		m->ps += 12;
+		p = seprint(p, e, " orig=%ud rcv=%ux xmt=%ux",
+			NetL(h->data), NetL(h->data+4),
+			NetL(h->data+8));
+		m->pr = nil;
+		break;
+	case InfoReq:
+	case InfoRep:
+		break;
+	case Unreachable:
+	case TimeExceed:
+	case SrcQuench:
+		m->ps += 4;
+		m->pr = &ip;
+		break;
+	case Redirect:
+		m->ps += 4;
+		m->pr = &ip;
+		p = seprint(p, e, "gw=%V", h->data);
+		break;
+	case ParamProb:
+		m->ps += 4;
+		m->pr = &ip;
+		p = seprint(p, e, "ptr=%2.2ux", h->data[0]);
+		break;
+	}
+	m->p = p;
+	return 0;
+}
+
+Proto icmp =
+{
+	"icmp",
+	p_compile,
+	p_filter,
+	p_seprint,
+	p_mux,
+	p_fields,
+	defaultframer,
+};