snoopy: add support for DNS packets

1 files changed, 429 insertions, 0 deletions

diff --git a/src/cmd/ip/snoopy/dns.c b/src/cmd/ip/snoopy/dns.c
new file mode 100644
index 00000000..144a4949
--- /dev/null
+++ b/src/cmd/ip/snoopy/dns.c
@@ -0,0 +1,429 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+#include "dat.h"
+#include "protos.h"
+
+enum
+{
+	/* RR types */
+	Ta=	1,
+	Tns=	2,
+	Tmd=	3,
+	Tmf=	4,
+	Tcname=	5,
+	Tsoa=	6,
+	Tmb=	7,
+	Tmg=	8,
+	Tmr=	9,
+	Tnull=	10,
+	Twks=	11,
+	Tptr=	12,
+	Thinfo=	13,
+	Tminfo=	14,
+	Tmx=	15,
+	Ttxt=	16,
+	Trp=	17,
+	Tsig=	24,
+	Tkey=	25,
+	Taaaa=	28,
+	Tcert=	37,
+
+	/* query types (all RR types are also queries) */
+	Tixfr=	251,	/* incremental zone transfer */
+	Taxfr=	252,	/* zone transfer */
+	Tmailb=	253,	/* { Tmb, Tmg, Tmr } */	
+	Tall=	255,	/* all records */
+
+	/* classes */
+	Csym=	0,	/* internal symbols */
+	Cin=	1,	/* internet */
+	Ccs,		/* CSNET (obsolete) */
+	Cch,		/* Chaos net */
+	Chs,		/* Hesiod (?) */
+
+	/* class queries (all class types are also queries) */
+	Call=	255,	/* all classes */
+
+	/* opcodes */
+	Oquery=		0<<11,		/* normal query */
+	Oinverse=	1<<11,		/* inverse query */
+	Ostatus=	2<<11,		/* status request */
+	Onotify=	4<<11,		/* notify slaves of updates */
+	Omask=		0xf<<11,	/* mask for opcode */
+
+	/* response codes */
+	Rok=		0,
+	Rformat=	1,	/* format error */
+	Rserver=	2,	/* server failure (e.g. no answer from something) */
+	Rname=		3,	/* bad name */
+	Runimplimented=	4,	/* unimplemented */
+	Rrefused=	5,	/* we don't like you */
+	Rmask=		0xf,	/* mask for response */
+	Rtimeout=	0x10,	/* timeout sending (for internal use only) */
+
+	/* bits in flag word (other than opcode and response) */
+	Fresp=		1<<15,	/* message is a response */
+	Fauth=		1<<10,	/* true if an authoritative response */
+	Ftrunc=		1<<9,	/* truncated message */
+	Frecurse=	1<<8,	/* request recursion */
+	Fcanrec=	1<<7,	/* server can recurse */
+};
+
+typedef struct Hdr	Hdr;
+struct Hdr
+{
+	uchar	id[2];
+	uchar	flags[2];
+	uchar	qdcount[2];
+	uchar	ancount[2];
+	uchar	nscount[2];
+	uchar	arcount[2];
+};
+
+
+static char*
+getstr(uchar **pp, int *len, uchar *ep)
+{
+	uchar *p;
+	int n;
+	
+	p = *pp;
+	n = *p++;
+	if(p+n > ep)
+		return nil;
+	*len = n;
+	*pp = p+n;
+	return (char*)p;
+}
+
+static char*
+getname(uchar **pp, uchar *bp, uchar *ep)
+{
+	static char buf[2][512];
+	static int toggle;
+	char *tostart, *to;
+	char *toend;
+	int len, off, pointer, n;
+	uchar *p;
+
+	to = buf[toggle^=1];
+	toend = to+sizeof buf[0];
+	tostart = to;
+	p = *pp;
+	len = 0;
+	pointer = 0;
+	while(p < ep && *p){
+		if((*p & 0xc0) == 0xc0){
+			/* pointer to another spot in message */
+			if(pointer == 0)
+				*pp = p + 2;
+			if(pointer++ > 10)
+				return nil;
+			off = ((p[0]<<8) + p[1]) & 0x3ff;
+			p = bp + off;
+			if(p >= ep)
+				return nil;
+			n = 0;
+			continue;
+		}
+		n = *p++;
+		if(to+n >= toend || p+n > ep)
+			return nil;
+		memmove(to, p, n);
+		to += n;
+		p += n;
+		if(*p){
+			if(to >= toend)
+				return nil;
+			*to++ = '.';
+		}
+	}
+	if(to >= toend || p >= ep)
+		return nil;
+	*to = 0;
+	if(!pointer)
+		*pp = ++p;
+	return tostart;
+}
+
+static char*
+tname(int type)
+{
+	static char buf[20];
+
+	switch(type){
+	case Ta:
+		return "a";
+	case Tns:
+		return "ns";
+	case Tmd:
+		return "md";
+	case Tmf:
+		return "mf";
+	case Tcname:
+		return "cname";
+	case Tsoa:
+		return "soa";
+	case Tmb:
+		return "mb";
+	case Tmg:
+		return "mg";
+	case Tmr:
+		return "mr";
+	case Tnull:
+		return "null";
+	case Twks:
+		return "wks";
+	case Tptr:
+		return "ptr";
+	case Thinfo:
+		return "hinfo";
+	case Tminfo:
+		return "minfo";
+	case Tmx:
+		return "mx";
+	case Ttxt:
+		return "txt";
+	case Trp:
+		return "rp";
+	case Tsig:
+		return "sig";
+	case Tkey:
+		return "key";
+	case Taaaa:
+		return "aaaa";
+	case Tcert:
+		return "cert";
+	case Tixfr:
+		return "ixfr";
+	case Taxfr:
+		return "axfr";
+	case Tmailb:
+		return "mailb";
+	case Tall:
+		return "all";
+	}
+	snprint(buf, sizeof buf, "%d", type);
+	return buf;
+}
+
+static char*
+cname(int class)
+{
+	static char buf[40];
+
+	if(class == Cin)
+		return "";
+	
+	snprint(buf, sizeof buf, "class=%d", class);
+	return buf;
+}
+
+#define PR(name, len) utfnlen(name, len), name
+
+extern int sflag;
+
+static int
+p_seprint(Msg *m)
+{
+	int i, pref;
+	Hdr *h;
+	uchar *p, *ep;
+	int an, ns, ar, rlen;
+	char *name, *prefix;
+	int len1, len2;
+	char *sym1, *sym2, *sep;
+	int type;
+	static int first = 1;
+	
+	if(first){
+		first = 0;
+		quotefmtinstall();
+	}
+
+	if(m->pe - m->ps < sizeof(Hdr))
+		return -1;
+	h = (Hdr*)m->ps;
+	m->pr = nil;
+
+	m->p = seprint(m->p, m->e, "id=%d flags=%04ux %d/%d/%d/%d",
+			NetS(h->id), NetS(h->flags),
+			NetS(h->qdcount), NetS(h->ancount),
+			NetS(h->nscount), NetS(h->arcount));
+	sep = ")\n\t";
+	if(sflag)
+		sep = ") ";
+	p = m->ps + sizeof(Hdr);
+	for(i=0; i<NetS(h->qdcount); i++){
+		name = getname(&p, m->ps, m->pe);
+		if(name == nil || p+4 > m->pe)
+			goto error;
+		m->p = seprint(m->p, m->e, "%sq=(%q %s%s",
+			sep, name, tname(NetS(p)), cname(NetS(p+2)));
+		p += 4;
+	}
+
+	an = NetS(h->ancount);
+	ns = NetS(h->nscount);
+	ar = NetS(h->arcount);
+	while(an+ns+ar > 0){
+		if(an > 0){
+			prefix = "an";
+			an--;
+		}else if(ns > 0){
+			prefix = "ns";
+			ns--;
+		}else{
+			prefix = "ar";
+			ar--;
+		}
+		name = getname(&p, m->ps, m->pe);
+		if(name == nil || p+10 > m->pe)
+			goto error;
+		type = NetS(p);
+		rlen = NetS(p+8);
+		ep = p+10+rlen;
+		if(ep > m->pe)
+			goto error;
+		m->p = seprint(m->p, m->e, "%s%s=(%q %s%s | ttl=%lud",
+			sep, prefix, name, tname(type), cname(NetS(p+2)), NetL(p+4), rlen);
+		p += 10;
+		switch(type){
+		default:
+			p = ep;
+			break;
+		case Thinfo:
+			sym1 = getstr(&p, &len1, ep);
+			if(sym1 == nil)
+				goto error;
+			sym2 = getstr(&p, &len2, ep);
+			if(sym2 == nil)
+				goto error;
+			m->p = seprint(m->p, m->e, " cpu=%.*s os=%.*s",
+				PR(sym1, len1),
+				PR(sym2, len2));
+			break;
+		case Tcname:
+		case Tmb:
+		case Tmd:
+		case Tmf:
+		case Tns:
+		case Tmg:
+		case Tmr:
+		case Tptr:
+			sym1 = getname(&p, m->ps, m->pe);
+			if(sym1 == nil)
+				goto error;
+			m->p = seprint(m->p, m->e, " %q", sym1);
+			break;
+		case Tminfo:
+			sym1 = getname(&p, m->ps, m->pe);
+			if(sym1 == nil)
+				goto error;
+			sym2 = getname(&p, m->ps, m->pe);
+			if(sym2 == nil)
+				goto error;
+			m->p = seprint(m->p, m->e, " %q %q", sym1, sym2);
+			break;
+		case Tmx:
+			if(p+2 >= ep)
+				goto error;
+			pref = NetS(p);
+			p += 2;
+			sym1 = getname(&p, m->ps, m->pe);
+			if(sym1 == nil)
+				goto error;
+			break;
+		case Ta:
+			if(p+4 > ep)
+				goto error;
+			m->p = seprint(m->p, m->e, " %V", p);
+			p += 4;
+			break;
+		case Taaaa:
+			if(p+16 > ep)
+				goto error;
+			m->p = seprint(m->p, m->e, " %I", p);
+			p += 16;
+			break;
+		case Tsoa:
+			sym1 = getname(&p, m->ps, m->pe);
+			if(sym1 == nil)
+				goto error;
+			sym2 = getname(&p, m->ps, m->pe);
+			if(sym2 == nil)
+				goto error;
+			if(p+20 > ep)
+				goto error;
+			m->p = seprint(m->p, m->e, " host=%q rmb=%q serial=%lud refresh=%lud retry=%lud expire=%lud minttl=%lud",
+				sym1, sym2, NetL(p), NetL(p+4),
+				NetL(p+8), NetL(p+12), NetL(p+16));
+			break;
+		case Ttxt:
+			while(p < ep){
+				sym1 = getstr(&p, &len1, ep);
+				if(sym1 == nil)
+					goto error;
+				m->p = seprint(m->p, m->e, " %.*q", PR(sym1, len1));
+			}
+			break;
+		case Tnull:
+			m->p = seprint(m->p, m->e, " %.*H", rlen, p);
+			p += rlen;
+			break;
+		case Trp:
+			sym1 = getname(&p, m->ps, m->pe);
+			if(sym1 == nil)
+				goto error;
+			sym2 = getname(&p, m->ps, m->pe);
+			if(sym2 == nil)
+				goto error;
+			m->p = seprint(m->p, m->e, " rmb=%q rp=%q", sym1, sym2);
+			break;
+		case Tkey:
+			if(rlen < 4)
+				goto error;
+			m->p = seprint(m->p, m->e, " flags=%04ux proto=%d alg=%d %.*H",
+				NetS(p), p[3], p[4], rlen-4, p+4);
+			p += rlen;
+			break;
+ 
+		case Tsig:
+			if(rlen < 18)
+				goto error;
+			m->p = seprint(m->p, m->e, " type=%d alg=%d labels=%d ttl=%lud exp=%lud incep=%lud tag=%d %.*H",
+				NetS(p), p[3], p[4], NetL(p+4), NetL(p+8), NetL(p+12), NetS(p+16),
+				rlen-18, p+18);
+			p += rlen;
+			break;
+
+		case Tcert:
+			if(rlen < 5)
+				goto error;
+			m->p = seprint(m->p, m->e, " type=%d tag=%d alg=%d %.*H",
+				NetS(p), NetS(p+2), p[4], rlen-5, p+5);
+			p += rlen;
+			break;
+		}
+		if(p != ep)
+			goto error;
+	}	
+	return 0;
+
+error:
+	m->p = seprint(m->p, m->e, " packet error!");
+	return 0;
+}
+
+Proto dns =
+{
+	"dns",
+	nil,
+	nil,
+	p_seprint,
+	nil,
+	nil,
+	nil,
+	defaultframer
+};