add dns

1 files changed, 460 insertions, 0 deletions

diff --git a/src/cmd/ndb/convM2DNS.c b/src/cmd/ndb/convM2DNS.c
new file mode 100755
index 00000000..47b35616
--- /dev/null
+++ b/src/cmd/ndb/convM2DNS.c
@@ -0,0 +1,460 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+#include <bio.h>
+#include <ndb.h>
+#include "dns.h"
+
+typedef struct Scan	Scan;
+struct Scan
+{
+	uchar	*base;
+	uchar	*p;
+	uchar	*ep;
+	char	*err;
+};
+
+#define NAME(x)		gname(x, sp)
+#define SYMBOL(x)	(x = gsym(sp))
+#define STRING(x)	(x = gstr(sp))
+#define USHORT(x)	(x = gshort(sp))
+#define ULONG(x)	(x = glong(sp))
+#define UCHAR(x)	(x = gchar(sp))
+#define V4ADDR(x)	(x = gv4addr(sp))
+#define V6ADDR(x)	(x = gv6addr(sp))
+#define BYTES(x, y)	(y = gbytes(sp, &x, len - (sp->p - data)))
+
+static char *toolong = "too long";
+
+/*
+ *  get a ushort/ulong
+ */
+static ushort
+gchar(Scan *sp)
+{
+	ushort x;
+
+	if(sp->err)
+		return 0;
+	if(sp->ep - sp->p < 1){
+		sp->err = toolong;
+		return 0;
+	}
+	x = sp->p[0];
+	sp->p += 1;
+	return x;
+}
+static ushort
+gshort(Scan *sp)
+{
+	ushort x;
+
+	if(sp->err)
+		return 0;
+	if(sp->ep - sp->p < 2){
+		sp->err = toolong;
+		return 0;
+	}
+	x = (sp->p[0]<<8) | sp->p[1];
+	sp->p += 2;
+	return x;
+}
+static ulong
+glong(Scan *sp)
+{
+	ulong x;
+
+	if(sp->err)
+		return 0;
+	if(sp->ep - sp->p < 4){
+		sp->err = toolong;
+		return 0;
+	}
+	x = (sp->p[0]<<24) | (sp->p[1]<<16) | (sp->p[2]<<8) | sp->p[3];
+	sp->p += 4;
+	return x;
+}
+
+/*
+ *  get an ip address
+ */
+static DN*
+gv4addr(Scan *sp)
+{
+	char addr[32];
+
+	if(sp->err)
+		return 0;
+	if(sp->ep - sp->p < 4){
+		sp->err = toolong;
+		return 0;
+	}
+	snprint(addr, sizeof(addr), "%V", sp->p);
+	sp->p += 4;
+
+	return dnlookup(addr, Cin, 1);
+}
+static DN*
+gv6addr(Scan *sp)
+{
+	char addr[64];
+
+	if(sp->err)
+		return 0;
+	if(sp->ep - sp->p < IPaddrlen){
+		sp->err = toolong;
+		return 0;
+	}
+	snprint(addr, sizeof(addr), "%I", sp->p);
+	sp->p += IPaddrlen;
+
+	return dnlookup(addr, Cin, 1);
+}
+
+/*
+ *  get a string.  make it an internal symbol.
+ */
+static DN*
+gsym(Scan *sp)
+{
+	int n;
+	char sym[Strlen+1];
+
+	if(sp->err)
+		return 0;
+	n = *(sp->p++);
+	if(sp->p+n > sp->ep){
+		sp->err = toolong;
+		return 0;
+	}
+
+	if(n > Strlen){
+		sp->err = "illegal string";
+		return 0;
+	}
+	strncpy(sym, (char*)sp->p, n);
+	sym[n] = 0;
+	sp->p += n;
+
+	return dnlookup(sym, Csym, 1);
+}
+
+/*
+ *  get a string.  don't make it an internal symbol.
+ */
+static Txt*
+gstr(Scan *sp)
+{
+	int n;
+	char sym[Strlen+1];
+	Txt *t;
+
+	if(sp->err)
+		return 0;
+	n = *(sp->p++);
+	if(sp->p+n > sp->ep){
+		sp->err = toolong;
+		return 0;
+	}
+
+	if(n > Strlen){
+		sp->err = "illegal string";
+		return 0;
+	}
+	strncpy(sym, (char*)sp->p, n);
+	sym[n] = 0;
+	sp->p += n;
+
+	t = emalloc(sizeof(*t));
+	t->next = nil;
+	t->p = estrdup(sym);
+	return t;
+}
+
+/*
+ *  get a sequence of bytes
+ */
+static int
+gbytes(Scan *sp, uchar **p, int n)
+{
+	if(sp->err)
+		return 0;
+	if(sp->p+n > sp->ep || n < 0){
+		sp->err = toolong;
+		return 0;
+	}
+	*p = emalloc(n);
+	memmove(*p, sp->p, n);
+	sp->p += n;
+
+	return n;
+}
+
+/*
+ *  get a domain name.  'to' must point to a buffer at least Domlen+1 long.
+ */
+static char*
+gname(char *to, Scan *sp)
+{
+	int len, off;
+	int pointer;
+	int n;
+	char *tostart;
+	char *toend;
+	uchar *p;
+
+	tostart = to;
+	if(sp->err)
+		goto err;
+	pointer = 0;
+	p = sp->p;
+	toend = to + Domlen;
+	for(len = 0; *p; len += pointer ? 0 : (n+1)){
+		if((*p & 0xc0) == 0xc0){
+			/* pointer to other spot in message */
+			if(pointer++ > 10){
+				sp->err = "pointer loop";
+				goto err;
+			}
+			off = ((p[0]<<8) + p[1]) & 0x3ff;
+			p = sp->base + off;
+			if(p >= sp->ep){
+				sp->err = "bad pointer";
+				goto err;
+			}
+			n = 0;
+			continue;
+		}
+		n = *p++;
+		if(len + n < Domlen - 1){
+			if(to + n > toend){
+				sp->err = toolong;
+				goto err;
+			}
+			memmove(to, p, n);
+			to += n;
+		}
+		p += n;
+		if(*p){
+			if(to >= toend){
+				sp->err = toolong;
+				goto err;
+			}
+			*to++ = '.';
+		}
+	}
+	*to = 0;
+	if(pointer)
+		sp->p += len + 2;	/* + 2 for pointer */
+	else
+		sp->p += len + 1;	/* + 1 for the null domain */
+	return tostart;
+err:
+	*tostart = 0;
+	return tostart;
+}
+
+/*
+ *  convert the next RR from a message
+ */
+static RR*
+convM2RR(Scan *sp)
+{
+	RR *rp;
+	int type;
+	int class;
+	uchar *data;
+	int len;
+	char dname[Domlen+1];
+	Txt *t, **l;
+
+retry:
+	NAME(dname);
+	USHORT(type);
+	USHORT(class);
+
+	rp = rralloc(type);
+	rp->owner = dnlookup(dname, class, 1);
+	rp->type = type;
+
+	ULONG(rp->ttl);
+	rp->ttl += now;
+	USHORT(len);
+	data = sp->p;
+
+	if(sp->p + len > sp->ep)
+		sp->err = toolong;
+	if(sp->err){
+		rrfree(rp);
+		return 0;
+	}
+
+	switch(type){
+	default:
+		/* unknown type, just ignore it */
+		sp->p = data + len;
+		rrfree(rp);
+		goto retry;
+	case Thinfo:
+		SYMBOL(rp->cpu);
+		SYMBOL(rp->os);
+		break;
+	case Tcname:
+	case Tmb:
+	case Tmd:
+	case Tmf:
+	case Tns:
+		rp->host = dnlookup(NAME(dname), Cin, 1);
+		break;
+	case Tmg:
+	case Tmr:
+		rp->mb = dnlookup(NAME(dname), Cin, 1);
+		break;
+	case Tminfo:
+		rp->rmb = dnlookup(NAME(dname), Cin, 1);
+		rp->mb = dnlookup(NAME(dname), Cin, 1);
+		break;
+	case Tmx:
+		USHORT(rp->pref);
+		rp->host = dnlookup(NAME(dname), Cin, 1);
+		break;
+	case Ta:
+		V4ADDR(rp->ip);
+		break;
+	case Taaaa:
+		V6ADDR(rp->ip);
+		break;
+	case Tptr:
+		rp->ptr = dnlookup(NAME(dname), Cin, 1);
+		break;
+	case Tsoa:
+		rp->host = dnlookup(NAME(dname), Cin, 1);
+		rp->rmb = dnlookup(NAME(dname), Cin, 1);
+		ULONG(rp->soa->serial);
+		ULONG(rp->soa->refresh);
+		ULONG(rp->soa->retry);
+		ULONG(rp->soa->expire);
+		ULONG(rp->soa->minttl);
+		break;
+	case Ttxt:
+		l = &rp->txt;
+		*l = nil;
+		while(sp->p-data < len){
+			STRING(t);
+			*l = t;
+			l = &t->next;
+		}
+		break;
+	case Tnull:
+		BYTES(rp->null->data, rp->null->dlen);
+		break;
+	case Trp:
+		rp->rmb = dnlookup(NAME(dname), Cin, 1);
+		rp->rp = dnlookup(NAME(dname), Cin, 1);
+		break;
+	case Tkey:
+		USHORT(rp->key->flags);
+		UCHAR(rp->key->proto);
+		UCHAR(rp->key->alg);
+		BYTES(rp->key->data, rp->key->dlen);
+		break;
+	case Tsig:
+		USHORT(rp->sig->type);
+		UCHAR(rp->sig->alg);
+		UCHAR(rp->sig->labels);
+		ULONG(rp->sig->ttl);
+		ULONG(rp->sig->exp);
+		ULONG(rp->sig->incep);
+		USHORT(rp->sig->tag);
+		rp->sig->signer = dnlookup(NAME(dname), Cin, 1);
+		BYTES(rp->sig->data, rp->sig->dlen);
+		break;
+	case Tcert:
+		USHORT(rp->cert->type);
+		USHORT(rp->cert->tag);
+		UCHAR(rp->cert->alg);
+		BYTES(rp->cert->data, rp->cert->dlen);
+		break;
+	}
+	if(sp->p - data != len)
+		sp->err = "bad RR len";
+	return rp;
+}
+
+/*
+ *  convert the next question from a message
+ */
+static RR*
+convM2Q(Scan *sp)
+{
+	char dname[Domlen+1];
+	int type;
+	int class;
+	RR *rp;
+
+	NAME(dname);
+	USHORT(type);
+	USHORT(class);
+	if(sp->err)
+		return 0;
+
+	rp = rralloc(type);
+	rp->owner = dnlookup(dname, class, 1);
+
+	return rp;
+}
+
+static RR*
+rrloop(Scan *sp, int count, int quest)
+{
+	int i;
+	static char errbuf[64];
+	RR *first, *rp, **l;
+
+	if(sp->err)
+		return 0;
+	l = &first;
+	first = 0;
+	for(i = 0; i < count; i++){
+		rp = quest ? convM2Q(sp) : convM2RR(sp);
+		if(rp == 0)
+			break;
+		if(sp->err){
+			rrfree(rp);
+			break;
+		}
+		*l = rp;
+		l = &rp->next;
+	}
+	return first;
+}
+
+/*
+ *  convert the next DNS from a message stream
+ */
+char*
+convM2DNS(uchar *buf, int len, DNSmsg *m)
+{
+	Scan scan;
+	Scan *sp;
+	char *err;
+
+	scan.base = buf;
+	scan.p = buf;
+	scan.ep = buf + len;
+	scan.err = 0;
+	sp = &scan;
+	memset(m, 0, sizeof(DNSmsg));
+	USHORT(m->id);
+	USHORT(m->flags);
+	USHORT(m->qdcount);
+	USHORT(m->ancount);
+	USHORT(m->nscount);
+	USHORT(m->arcount);
+	m->qd = rrloop(sp, m->qdcount, 1);
+	m->an = rrloop(sp, m->ancount, 0);
+	m->ns = rrloop(sp, m->nscount, 0);
+	err = scan.err;				/* live with bad ar's */
+	m->ar = rrloop(sp, m->arcount, 0);
+	return err;
+}