move dns.[ch] back to avahi-core/

git-svn-id: file:///home/lennart/svn/public/avahi/trunk@104 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

4 files changed, 923 insertions, 4 deletions

diff --git a/avahi-core/Makefile.am b/avahi-core/Makefile.am
index b692fcc..6920e8c 100644
--- a/avahi-core/Makefile.am
+++ b/avahi-core/Makefile.am
@@ -21,9 +21,11 @@ AM_CFLAGS=-I$(top_srcdir) -D_GNU_SOURCE
 
 # GLIB 2.0
 AM_CFLAGS+=$(GLIB20_CFLAGS)
-AM_LDADD=$(GLIB20_LIBS) ../avahi-common/libavahi-common.la
+AM_LDADD=$(GLIB20_LIBS)
 
-AM_CFLAGS+=-I$(top_srcdir)/avahi-common
+# Import stuff from avahi-common
+AM_CFLAGS+=-I$(top_srcdir)/avahi-common 
+AM_LDADD+=../avahi-common/libavahi-common.la
 
 # This cool debug trap works on i386/gcc only
 AM_CFLAGS+='-DDEBUG_TRAP=__asm__("int $$3")'
@@ -40,7 +42,8 @@ noinst_PROGRAMS = \
 	prioq-test \
 	avahi-test \
 	conformance-test \
-	avahi-reflector
+	avahi-reflector \
+	dns-test
 
 libavahi_core_la_SOURCES = \
 	timeeventq.c timeeventq.h\
@@ -61,7 +64,8 @@ libavahi_core_la_SOURCES = \
 	browse-domain.c \
 	browse-service-type.c \
 	browse-service.c \
-	resolve-service.c
+	resolve-service.c \
+	dns.c dns.h
 
 prioq_test_SOURCES = \
 	prioq-test.c  \
@@ -87,6 +91,12 @@ avahi_reflector_SOURCES = \
 avahi_reflector_CFLAGS = $(AM_CFLAGS)
 avahi_reflector_LDADD = $(AM_LDADD)
 
+dns_test_SOURCES = \
+	dns.c dns.h \
+        dns-test.c
+dns_test_CFLAGS = $(AM_CFLAGS)
+dns_test_LDADD = $(AM_LDADD)
+
 valgrind: avahi-test
 	libtool --mode=execute valgrind ./avahi-test
 
diff --git a/avahi-core/dns-test.c b/avahi-core/dns-test.c
new file mode 100644
index 0000000..aa36f2a
--- /dev/null
+++ b/avahi-core/dns-test.c
@@ -0,0 +1,60 @@
+/* $Id$ */
+
+/***
+  This file is part of avahi.
+ 
+  avahi is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+ 
+  avahi is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
+  Public License for more details.
+ 
+  You should have received a copy of the GNU Lesser General Public
+  License along with avahi; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "dns.h"
+#include "util.h"
+
+int main(int argc, char *argv[]) {
+    gchar t[256], *a, *b, *c, *d;
+    AvahiDnsPacket *p;
+
+    p = avahi_dns_packet_new(0);
+
+    avahi_dns_packet_append_name(p, a = "hello.hello.hello.de.");
+    avahi_dns_packet_append_name(p, b = "this is a test.hello.de."); 
+    avahi_dns_packet_append_name(p, c = "this\\.is\\.a\\.test\\.with\\.dots.hello.de."); 
+    avahi_dns_packet_append_name(p, d = "this\\\\is another\\ \\test.hello.de."); 
+
+    avahi_hexdump(AVAHI_DNS_PACKET_DATA(p), p->size);
+
+    avahi_dns_packet_consume_name(p, t, sizeof(t));
+    g_message(">%s<", t);
+    g_assert(avahi_domain_equal(a, t));
+    
+    avahi_dns_packet_consume_name(p, t, sizeof(t));
+    g_message(">%s<", t);
+    g_assert(avahi_domain_equal(b, t));
+
+    avahi_dns_packet_consume_name(p, t, sizeof(t));
+    g_message(">%s<", t);
+    g_assert(avahi_domain_equal(c, t));
+
+    avahi_dns_packet_consume_name(p, t, sizeof(t));
+    g_message(">%s<", t);
+    g_assert(avahi_domain_equal(d, t));
+    
+    avahi_dns_packet_free(p);
+    return 0;
+}
diff --git a/avahi-core/dns.c b/avahi-core/dns.c
new file mode 100644
index 0000000..9e19c9e
--- /dev/null
+++ b/avahi-core/dns.c
@@ -0,0 +1,744 @@
+/* $Id$ */
+
+/***
+  This file is part of avahi.
+ 
+  avahi is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+ 
+  avahi is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
+  Public License for more details.
+ 
+  You should have received a copy of the GNU Lesser General Public
+  License along with avahi; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <netinet/in.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "dns.h"
+#include "util.h"
+
+AvahiDnsPacket* avahi_dns_packet_new(guint mtu) {
+    AvahiDnsPacket *p;
+    guint max_size;
+
+    if (mtu <= 0)
+        max_size = AVAHI_DNS_PACKET_MAX_SIZE;
+    else if (mtu >= AVAHI_DNS_PACKET_EXTRA_SIZE)
+        max_size = mtu - AVAHI_DNS_PACKET_EXTRA_SIZE;
+    else
+        max_size = 0;
+
+    if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE)
+        max_size = AVAHI_DNS_PACKET_HEADER_SIZE;
+    
+    p = g_malloc(sizeof(AvahiDnsPacket) + max_size);
+    p->size = p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
+    p->max_size = max_size;
+    p->name_table = NULL;
+
+    memset(AVAHI_DNS_PACKET_DATA(p), 0, p->size);
+    return p;
+}
+
+AvahiDnsPacket* avahi_dns_packet_new_query(guint mtu) {
+    AvahiDnsPacket *p;
+
+    p = avahi_dns_packet_new(mtu);
+    avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+    return p;
+}
+
+AvahiDnsPacket* avahi_dns_packet_new_response(guint mtu, gboolean aa) {
+    AvahiDnsPacket *p;
+
+    p = avahi_dns_packet_new(mtu);
+    avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, aa, 0, 0, 0, 0, 0, 0, 0));
+    return p;
+}
+
+AvahiDnsPacket* avahi_dns_packet_new_reply(AvahiDnsPacket* p, guint mtu, gboolean copy_queries, gboolean aa) {
+    AvahiDnsPacket *r;
+    g_assert(p);
+
+    r = avahi_dns_packet_new_response(mtu, aa);
+
+    if (copy_queries) {
+        guint n, saved_rindex;
+
+        saved_rindex = p->rindex;
+        p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
+        
+        for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); n > 0; n--) {
+            AvahiKey *k;
+            gboolean unicast_response;
+
+            if ((k = avahi_dns_packet_consume_key(p, &unicast_response))) {
+                avahi_dns_packet_append_key(r, k, unicast_response);
+                avahi_key_unref(k);
+            }
+        }
+
+        p->rindex = saved_rindex;
+
+        avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_QDCOUNT, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT));
+    }
+
+    avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_ID, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID));
+
+    avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_FLAGS,
+                               (avahi_dns_packet_get_field(r, AVAHI_DNS_FIELD_FLAGS) & ~AVAHI_DNS_FLAG_OPCODE) |
+                               (avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_OPCODE));
+
+    return r;
+} 
+
+
+void avahi_dns_packet_free(AvahiDnsPacket *p) {
+    g_assert(p);
+
+    if (p->name_table)
+        g_hash_table_destroy(p->name_table);
+    
+    g_free(p);
+}
+
+void avahi_dns_packet_set_field(AvahiDnsPacket *p, guint index, guint16 v) {
+    g_assert(p);
+    g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
+    
+    ((guint16*) AVAHI_DNS_PACKET_DATA(p))[index] = g_htons(v);
+}
+
+guint16 avahi_dns_packet_get_field(AvahiDnsPacket *p, guint index) {
+    g_assert(p);
+    g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
+
+    return g_ntohs(((guint16*) AVAHI_DNS_PACKET_DATA(p))[index]);
+}
+
+void avahi_dns_packet_inc_field(AvahiDnsPacket *p, guint index) {
+    g_assert(p);
+
+    avahi_dns_packet_set_field(p, index, avahi_dns_packet_get_field(p, index) + 1);
+}   
+
+guint8* avahi_dns_packet_append_name(AvahiDnsPacket *p, const gchar *name) {
+    guint8 *d, *saved_ptr = NULL;
+    guint saved_size;
+    
+    g_assert(p);
+    g_assert(name);
+
+    saved_size = p->size;
+    saved_ptr = avahi_dns_packet_extend(p, 0);
+    
+    while (*name) {
+        guint8* prev;
+        const gchar *pname;
+        gchar label[64];
+
+        /* Check whether we can compress this name. */
+
+        if (p->name_table && (prev = g_hash_table_lookup(p->name_table, name))) {
+            guint index;
+            
+            g_assert(prev >= AVAHI_DNS_PACKET_DATA(p));
+            index = (guint) (prev - AVAHI_DNS_PACKET_DATA(p));
+
+            g_assert(index < p->size);
+
+            if (index < 0x4000) {
+                guint16 *t;
+                if (!(t = (guint16*) avahi_dns_packet_extend(p, sizeof(guint16))))
+                    return NULL;
+
+                *t = g_htons((0xC000 | index));
+                return saved_ptr;
+            }
+        }
+
+        pname = name;
+        
+        if (!(avahi_unescape_label(&name, label, sizeof(label))))
+            goto fail;
+
+        if (!(d = avahi_dns_packet_append_string(p, label)))
+            goto fail;
+
+        if (!p->name_table)
+            /* This works only for normalized domain names */
+            p->name_table = g_hash_table_new_full((GHashFunc) g_str_hash, (GEqualFunc) g_str_equal, g_free, NULL);
+
+        g_hash_table_insert(p->name_table, g_strdup(pname), d);
+    }
+
+    if (!(d = avahi_dns_packet_extend(p, 1)))
+        goto fail;
+    
+    *d = 0;
+
+    return saved_ptr;
+
+fail:
+    p->size = saved_size;
+    return NULL;
+}
+
+guint8* avahi_dns_packet_append_uint16(AvahiDnsPacket *p, guint16 v) {
+    guint8 *d;
+    g_assert(p);
+    
+    if (!(d = avahi_dns_packet_extend(p, sizeof(guint16))))
+        return NULL;
+    
+    *((guint16*) d) = g_htons(v);
+    return d;
+}
+
+guint8 *avahi_dns_packet_append_uint32(AvahiDnsPacket *p, guint32 v) {
+    guint8 *d;
+    g_assert(p);
+
+    if (!(d = avahi_dns_packet_extend(p, sizeof(guint32))))
+        return NULL;
+    
+    *((guint32*) d) = g_htonl(v);
+
+    return d;
+}
+
+guint8 *avahi_dns_packet_append_bytes(AvahiDnsPacket  *p, gconstpointer b, guint l) {
+    guint8* d;
+
+    g_assert(p);
+    g_assert(b);
+    g_assert(l);
+
+    if (!(d = avahi_dns_packet_extend(p, l)))
+        return NULL;
+
+    memcpy(d, b, l);
+    return d;
+}
+
+guint8* avahi_dns_packet_append_string(AvahiDnsPacket *p, const gchar *s) {
+    guint8* d;
+    guint k;
+    
+    g_assert(p);
+    g_assert(s);
+
+    if ((k = strlen(s)) >= 255)
+        k = 255;
+    
+    if (!(d = avahi_dns_packet_extend(p, k+1)))
+        return NULL;
+
+    *d = (guint8) k;
+    memcpy(d+1, s, k);
+
+    return d;
+}
+
+guint8 *avahi_dns_packet_extend(AvahiDnsPacket *p, guint l) {
+    guint8 *d;
+    
+    g_assert(p);
+
+    if (p->size+l > p->max_size)
+        return NULL;
+    
+    d = AVAHI_DNS_PACKET_DATA(p) + p->size;
+    p->size += l;
+    
+    return d;
+}
+
+gint avahi_dns_packet_check_valid(AvahiDnsPacket *p) {
+    guint16 flags;
+    g_assert(p);
+
+    if (p->size < 12)
+        return -1;
+
+    flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS);
+
+    if (flags & AVAHI_DNS_FLAG_OPCODE || flags & AVAHI_DNS_FLAG_RCODE)
+        return -1;
+
+    return 0;
+}
+
+gint avahi_dns_packet_is_query(AvahiDnsPacket *p) {
+    g_assert(p);
+    
+    return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_QR);
+}
+
+static gint consume_labels(AvahiDnsPacket *p, guint index, gchar *ret_name, guint l) {
+    gint ret = 0;
+    int compressed = 0;
+    int first_label = 1;
+    g_assert(p && ret_name && l);
+    
+    for (;;) {
+        guint8 n;
+
+        if (index+1 > p->size)
+            return -1;
+
+        n = AVAHI_DNS_PACKET_DATA(p)[index];
+
+        if (!n) {
+            index++;
+            if (!compressed)
+                ret++;
+
+            if (l < 1)
+                return -1;
+            *ret_name = 0;
+            
+            return ret;
+            
+        } else if (n <= 63) {
+            /* Uncompressed label */
+            index++;
+            if (!compressed)
+                ret++;
+        
+            if (index + n > p->size)
+                return -1;
+
+            if ((guint) n + 1 > l)
+                return -1;
+
+            if (!first_label) {
+                *(ret_name++) = '.';
+                l--;
+            } else
+                first_label = 0;
+
+            if (!(avahi_escape_label(AVAHI_DNS_PACKET_DATA(p) + index, n, &ret_name, &l)))
+                return -1;
+
+            index += n;
+            
+            if (!compressed)
+                ret += n;
+        } else if ((n & 0xC0) == 0xC0) {
+            /* Compressed label */
+
+            if (index+2 > p->size)
+                return -1;
+
+            index = ((guint) (AVAHI_DNS_PACKET_DATA(p)[index] & ~0xC0)) << 8 | AVAHI_DNS_PACKET_DATA(p)[index+1];
+
+            if (!compressed)
+                ret += 2;
+            
+            compressed = 1;
+        } else
+            return -1;
+    }
+}
+
+gint avahi_dns_packet_consume_name(AvahiDnsPacket *p, gchar *ret_name, guint l) {
+    gint r;
+    
+    if ((r = consume_labels(p, p->rindex, ret_name, l)) < 0)
+        return -1;
+
+    p->rindex += r;
+    return 0;
+}
+
+gint avahi_dns_packet_consume_uint16(AvahiDnsPacket *p, guint16 *ret_v) {
+    g_assert(p);
+    g_assert(ret_v);
+
+    if (p->rindex + sizeof(guint16) > p->size)
+        return -1;
+
+    *ret_v = g_ntohs(*((guint16*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
+    p->rindex += sizeof(guint16);
+
+    return 0;
+}
+
+gint avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, guint32 *ret_v) {
+    g_assert(p);
+    g_assert(ret_v);
+
+    if (p->rindex + sizeof(guint32) > p->size)
+        return -1;
+
+    *ret_v = g_ntohl(*((guint32*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
+    p->rindex += sizeof(guint32);
+    
+    return 0;
+}
+
+gint avahi_dns_packet_consume_bytes(AvahiDnsPacket *p, gpointer ret_data, guint l) {
+    g_assert(p);
+    g_assert(ret_data);
+    g_assert(l > 0);
+    
+    if (p->rindex + l > p->size)
+        return -1;
+
+    memcpy(ret_data, AVAHI_DNS_PACKET_DATA(p) + p->rindex, l);
+    p->rindex += l;
+
+    return 0;
+}
+
+gint avahi_dns_packet_consume_string(AvahiDnsPacket *p, gchar *ret_string, guint l) {
+    guint k;
+    
+    g_assert(p);
+    g_assert(ret_string);
+    g_assert(l > 0);
+
+    if (p->rindex >= p->size)
+        return -1;
+
+    k = AVAHI_DNS_PACKET_DATA(p)[p->rindex];
+
+    if (p->rindex+1+k > p->size)
+        return -1;
+
+    if (l > k+1)
+        l = k+1;
+
+    memcpy(ret_string, AVAHI_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
+    ret_string[l-1] = 0;
+
+    
+    p->rindex += 1+k;
+
+    return 0;
+    
+}
+
+gconstpointer avahi_dns_packet_get_rptr(AvahiDnsPacket *p) {
+    g_assert(p);
+    
+    if (p->rindex > p->size)
+        return NULL;
+
+    return AVAHI_DNS_PACKET_DATA(p) + p->rindex;
+}
+
+gint avahi_dns_packet_skip(AvahiDnsPacket *p, guint length) {
+    g_assert(p);
+
+    if (p->rindex + length > p->size)
+        return -1;
+
+    p->rindex += length;
+    return 0;
+}
+
+AvahiRecord* avahi_dns_packet_consume_record(AvahiDnsPacket *p, gboolean *ret_cache_flush) {
+    gchar name[257], buf[257];
+    guint16 type, class;
+    guint32 ttl;
+    guint16 rdlength;
+    AvahiRecord *r = NULL;
+    gconstpointer start;
+
+    g_assert(p);
+    g_assert(ret_cache_flush);
+
+/*     g_message("consume_record()"); */
+
+    if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
+        avahi_dns_packet_consume_uint16(p, &type) < 0 ||
+        avahi_dns_packet_consume_uint16(p, &class) < 0 ||
+        avahi_dns_packet_consume_uint32(p, &ttl) < 0 ||
+        avahi_dns_packet_consume_uint16(p, &rdlength) < 0 ||
+        p->rindex + rdlength > p->size)
+        goto fail;
+
+/*     g_message("name = %s, rdlength = %u", name, rdlength); */
+
+    *ret_cache_flush = !!(class & AVAHI_DNS_CACHE_FLUSH);
+    class &= ~AVAHI_DNS_CACHE_FLUSH;
+    
+    start = avahi_dns_packet_get_rptr(p);
+    
+    r = avahi_record_new_full(name, class, type);
+    
+    switch (type) {
+        case AVAHI_DNS_TYPE_PTR:
+        case AVAHI_DNS_TYPE_CNAME:
+
+/*             g_message("ptr"); */
+            
+            if (avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
+                goto fail;
+
+            r->data.ptr.name = g_strdup(buf);
+            break;
+
+            
+        case AVAHI_DNS_TYPE_SRV:
+
+/*             g_message("srv"); */
+            
+            if (avahi_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
+                avahi_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
+                avahi_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
+                avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
+                goto fail;
+            
+            r->data.srv.name = g_strdup(buf);
+            break;
+
+        case AVAHI_DNS_TYPE_HINFO:
+            
+/*             g_message("hinfo"); */
+
+            if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
+                goto fail;
+
+            r->data.hinfo.cpu = g_strdup(buf);
+
+            if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
+                goto fail;
+
+            r->data.hinfo.os = g_strdup(buf);
+            break;
+
+        case AVAHI_DNS_TYPE_TXT:
+
+/*             g_message("txt"); */
+
+            if (rdlength > 0) {
+                r->data.txt.string_list = avahi_string_list_parse(avahi_dns_packet_get_rptr(p), rdlength);
+                
+                if (avahi_dns_packet_skip(p, rdlength) < 0)
+                    goto fail;
+            } else
+                r->data.txt.string_list = NULL;
+            
+            break;
+
+        case AVAHI_DNS_TYPE_A:
+
+/*             g_message("A"); */
+
+            if (avahi_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(AvahiIPv4Address)) < 0)
+                goto fail;
+            
+            break;
+
+        case AVAHI_DNS_TYPE_AAAA:
+
+/*             g_message("aaaa"); */
+            
+            if (avahi_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(AvahiIPv6Address)) < 0)
+                goto fail;
+            
+            break;
+            
+        default:
+
+/*             g_message("generic"); */
+            
+            if (rdlength > 0) {
+
+                r->data.generic.data = g_memdup(avahi_dns_packet_get_rptr(p), rdlength);
+                
+                if (avahi_dns_packet_skip(p, rdlength) < 0)
+                    goto fail;
+            }
+
+            break;
+    }
+
+/*     g_message("%i == %u ?", (guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start, rdlength); */
+    
+    /* Check if we read enough data */
+    if ((guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start != rdlength)
+        goto fail;
+    
+    r->ttl = ttl;
+
+    return r;
+
+fail:
+    if (r)
+        avahi_record_unref(r);
+
+    return NULL;
+}
+
+AvahiKey* avahi_dns_packet_consume_key(AvahiDnsPacket *p, gboolean *ret_unicast_response) {
+    gchar name[256];
+    guint16 type, class;
+
+    g_assert(p);
+    g_assert(ret_unicast_response);
+
+    if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
+        avahi_dns_packet_consume_uint16(p, &type) < 0 ||
+        avahi_dns_packet_consume_uint16(p, &class) < 0)
+        return NULL;
+
+    *ret_unicast_response = !!(class & AVAHI_DNS_UNICAST_RESPONSE);
+    class &= ~AVAHI_DNS_UNICAST_RESPONSE;
+
+    return avahi_key_new(name, class, type);
+}
+
+guint8* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, gboolean unicast_response) {
+    guint8 *t;
+    guint size;
+    
+    g_assert(p);
+    g_assert(k);
+
+    size = p->size;
+    
+    if (!(t = avahi_dns_packet_append_name(p, k->name)) ||
+        !avahi_dns_packet_append_uint16(p, k->type) ||
+        !avahi_dns_packet_append_uint16(p, k->class | (unicast_response ? AVAHI_DNS_UNICAST_RESPONSE : 0))) {
+        p->size = size;
+        return NULL;
+    }
+
+    return t;
+}
+
+guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush, guint max_ttl) {
+    guint8 *t, *l, *start;
+    guint size;
+
+    g_assert(p);
+    g_assert(r);
+
+    size = p->size;
+
+    if (!(t = avahi_dns_packet_append_name(p, r->key->name)) ||
+        !avahi_dns_packet_append_uint16(p, r->key->type) ||
+        !avahi_dns_packet_append_uint16(p, cache_flush ? (r->key->class | AVAHI_DNS_CACHE_FLUSH) : (r->key->class &~ AVAHI_DNS_CACHE_FLUSH)) ||
+        !avahi_dns_packet_append_uint32(p, (max_ttl && r->ttl > max_ttl) ? max_ttl : r->ttl) ||
+        !(l = avahi_dns_packet_append_uint16(p, 0)))
+        goto fail;
+
+    start = avahi_dns_packet_extend(p, 0);
+
+    switch (r->key->type) {
+        
+        case AVAHI_DNS_TYPE_PTR:
+        case AVAHI_DNS_TYPE_CNAME :
+
+            if (!(avahi_dns_packet_append_name(p, r->data.ptr.name)))
+                goto fail;
+            
+            break;
+
+        case AVAHI_DNS_TYPE_SRV:
+
+            if (!avahi_dns_packet_append_uint16(p, r->data.srv.priority) ||
+                !avahi_dns_packet_append_uint16(p, r->data.srv.weight) ||
+                !avahi_dns_packet_append_uint16(p, r->data.srv.port) ||
+                !avahi_dns_packet_append_name(p, r->data.srv.name))
+                goto fail;
+
+            break;
+
+        case AVAHI_DNS_TYPE_HINFO:
+            if (!avahi_dns_packet_append_string(p, r->data.hinfo.cpu) ||
+                !avahi_dns_packet_append_string(p, r->data.hinfo.os))
+                goto fail;
+
+            break;
+
+        case AVAHI_DNS_TYPE_TXT: {
+
+            guint8 *data;
+            guint size;
+
+            size = avahi_string_list_serialize(r->data.txt.string_list, NULL, 0);
+
+/*             g_message("appending string: %u %p", size, r->data.txt.string_list); */
+
+            if (!(data = avahi_dns_packet_extend(p, size)))
+                goto fail;
+
+            avahi_string_list_serialize(r->data.txt.string_list, data, size);
+            break;
+        }
+
+
+        case AVAHI_DNS_TYPE_A:
+
+            if (!avahi_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
+                goto fail;
+            
+            break;
+
+        case AVAHI_DNS_TYPE_AAAA:
+            
+            if (!avahi_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
+                goto fail;
+            
+            break;
+            
+        default:
+
+            if (r->data.generic.size &&
+                avahi_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
+                goto fail;
+
+            break;
+    }
+
+
+
+    
+    size = avahi_dns_packet_extend(p, 0) - start;
+    g_assert(size <= 0xFFFF);
+
+/*     g_message("appended %u", size); */
+
+    * (guint16*) l = g_htons((guint16) size);
+    
+    return t;
+
+
+fail:
+    p->size = size;
+    return NULL;
+}
+
+gboolean avahi_dns_packet_is_empty(AvahiDnsPacket *p) {
+    g_assert(p);
+
+    return p->size <= AVAHI_DNS_PACKET_HEADER_SIZE;
+}
+
+guint avahi_dns_packet_space(AvahiDnsPacket *p) {
+    g_assert(p);
+
+    g_assert(p->size <= p->max_size);
+    
+    return p->max_size - p->size;
+}
diff --git a/avahi-core/dns.h b/avahi-core/dns.h
new file mode 100644
index 0000000..03d9798
--- /dev/null
+++ b/avahi-core/dns.h
@@ -0,0 +1,105 @@
+#ifndef foodnshfoo
+#define foodnshfoo
+
+/* $Id$ */
+
+/***
+  This file is part of avahi.
+ 
+  avahi is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+ 
+  avahi is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
+  Public License for more details.
+ 
+  You should have received a copy of the GNU Lesser General Public
+  License along with avahi; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#include <glib.h>
+
+#include "rr.h"
+
+#define AVAHI_DNS_PACKET_MAX_SIZE 9000
+#define AVAHI_DNS_PACKET_HEADER_SIZE 12
+#define AVAHI_DNS_PACKET_EXTRA_SIZE 48
+
+typedef struct AvahiDnsPacket {
+    guint size, rindex, max_size;
+    GHashTable *name_table; /* for name compression */
+} AvahiDnsPacket;
+
+#define AVAHI_DNS_PACKET_DATA(p) (((guint8*) p) + sizeof(AvahiDnsPacket))
+
+AvahiDnsPacket* avahi_dns_packet_new(guint mtu);
+AvahiDnsPacket* avahi_dns_packet_new_query(guint mtu);
+AvahiDnsPacket* avahi_dns_packet_new_response(guint mtu, gboolean aa);
+
+AvahiDnsPacket* avahi_dns_packet_new_reply(AvahiDnsPacket* p, guint mtu, gboolean copy_queries, gboolean aa);
+
+void avahi_dns_packet_free(AvahiDnsPacket *p);
+void avahi_dns_packet_set_field(AvahiDnsPacket *p, guint index, guint16 v);
+guint16 avahi_dns_packet_get_field(AvahiDnsPacket *p, guint index);
+void avahi_dns_packet_inc_field(AvahiDnsPacket *p, guint index);
+
+guint8 *avahi_dns_packet_extend(AvahiDnsPacket *p, guint l);
+
+guint8 *avahi_dns_packet_append_uint16(AvahiDnsPacket *p, guint16 v);
+guint8 *avahi_dns_packet_append_uint32(AvahiDnsPacket *p, guint32 v);
+guint8 *avahi_dns_packet_append_name(AvahiDnsPacket *p, const gchar *name);
+guint8 *avahi_dns_packet_append_bytes(AvahiDnsPacket  *p, gconstpointer, guint l);
+guint8* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, gboolean unicast_response);
+guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush, guint max_ttl);
+guint8* avahi_dns_packet_append_string(AvahiDnsPacket *p, const gchar *s);
+
+gint avahi_dns_packet_is_query(AvahiDnsPacket *p);
+gint avahi_dns_packet_check_valid(AvahiDnsPacket *p);
+
+gint avahi_dns_packet_consume_uint16(AvahiDnsPacket *p, guint16 *ret_v);
+gint avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, guint32 *ret_v);
+gint avahi_dns_packet_consume_name(AvahiDnsPacket *p, gchar *ret_name, guint l);
+gint avahi_dns_packet_consume_bytes(AvahiDnsPacket *p, gpointer ret_data, guint l);
+AvahiKey* avahi_dns_packet_consume_key(AvahiDnsPacket *p, gboolean *ret_unicast_response);
+AvahiRecord* avahi_dns_packet_consume_record(AvahiDnsPacket *p, gboolean *ret_cache_flush);
+gint avahi_dns_packet_consume_string(AvahiDnsPacket *p, gchar *ret_string, guint l);
+
+gconstpointer avahi_dns_packet_get_rptr(AvahiDnsPacket *p);
+
+gint avahi_dns_packet_skip(AvahiDnsPacket *p, guint length);
+
+gboolean avahi_dns_packet_is_empty(AvahiDnsPacket *p);
+guint avahi_dns_packet_space(AvahiDnsPacket *p);
+
+#define AVAHI_DNS_FIELD_ID 0
+#define AVAHI_DNS_FIELD_FLAGS 1
+#define AVAHI_DNS_FIELD_QDCOUNT 2
+#define AVAHI_DNS_FIELD_ANCOUNT 3
+#define AVAHI_DNS_FIELD_NSCOUNT 4
+#define AVAHI_DNS_FIELD_ARCOUNT 5
+
+#define AVAHI_DNS_FLAG_QR (1 << 15)
+#define AVAHI_DNS_FLAG_OPCODE (15 << 11)
+#define AVAHI_DNS_FLAG_RCODE (15)
+#define AVAHI_DNS_FLAG_TC (1 << 9)
+#define AVAHI_DNS_FLAG_AA (1 << 10)
+
+#define AVAHI_DNS_FLAGS(qr, opcode, aa, tc, rd, ra, z, ad, cd, rcode) \
+        (((guint16) !!qr << 15) |  \
+         ((guint16) (opcode & 15) << 11) | \
+         ((guint16) !!aa << 10) | \
+         ((guint16) !!tc << 9) | \
+         ((guint16) !!rd << 8) | \
+         ((guint16) !!ra << 7) | \
+         ((guint16) !!ad << 5) | \
+         ((guint16) !!cd << 4) | \
+         ((guint16) (rd & 15)))
+         
+
+#endif
+