+#include <netinet/in.h>
+
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "dns.h"
+#include "util.h"
flxDnsPacket* flx_dns_packet_new(guint max_size) {
flxDnsPacket *p;
p = g_malloc(sizeof(flxDnsPacket) + max_size);
p->size = p->rindex = FLX_DNS_PACKET_HEADER_SIZE;
p->max_size = max_size;
+ p->name_table = NULL;
memset(FLX_DNS_PACKET_DATA(p), 0, p->size);
return p;
flxDnsPacket *p;
p = flx_dns_packet_new(max_size);
- flx_dns_packet_set_field(p, DNS_FIELD_FLAGS, DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+ flx_dns_packet_set_field(p, FLX_DNS_FIELD_FLAGS, FLX_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
return p;
}
flxDnsPacket *p;
p = flx_dns_packet_new(max_size);
- flx_dns_packet_set_field(p, DNS_FIELD_FLAGS, DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+ flx_dns_packet_set_field(p, FLX_DNS_FIELD_FLAGS, FLX_DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0));
return p;
}
void flx_dns_packet_free(flxDnsPacket *p) {
g_assert(p);
+
+ if (p->name_table)
+ g_hash_table_destroy(p->name_table);
+
g_free(p);
}
return g_ntohs(((guint16*) FLX_DNS_PACKET_DATA(p))[index]);
}
+/* Read the first label from string dest, unescape "\" and append it to *name */
+static gchar *unescape_label(gchar *dest, guint size, const gchar **name) {
+ guint i = 0;
+ gchar *d;
+
+ g_assert(dest);
+ g_assert(size > 0);
+ g_assert(name);
+ g_assert(*name);
+
+ d = dest;
+
+ for (;;) {
+ if (i >= size)
+ return NULL;
+
+ if (**name == '.') {
+ (*name)++;
+ break;
+ }
+
+ if (**name == 0)
+ break;
+
+ if (**name == '\\') {
+ (*name) ++;
+
+ if (**name == 0)
+ break;
+ }
+
+ *(d++) = *((*name) ++);
+ i++;
+ }
+
+ g_assert(i < size);
+
+ *d = 0;
+
+ return dest;
+}
+
guint8* flx_dns_packet_append_name(flxDnsPacket *p, const gchar *name) {
- guint8 *d, *f = NULL;
+ guint8 *d, *saved_ptr = NULL;
guint saved_size;
g_assert(p);
g_assert(name);
saved_size = p->size;
+ saved_ptr = flx_dns_packet_extend(p, 0);
+
+ while (*name) {
+ guint n;
+ guint8* prev;
+ const gchar *pname;
+ char label[64];
- for (;;) {
- guint n = strcspn(name, ".");
- if (!n || n > 63)
- goto fail;
-
- if (!(d = flx_dns_packet_extend(p, n+1)))
- goto fail;
+ /* Check whether we can compress this name. */
+
+ if (p->name_table && (prev = g_hash_table_lookup(p->name_table, name))) {
+ guint index;
- if (!f)
- f = d;
- d[0] = n;
- memcpy(d+1, name, n);
+ g_assert(prev >= FLX_DNS_PACKET_DATA(p));
+ index = (guint) (prev - FLX_DNS_PACKET_DATA(p));
- name += n;
+ g_assert(index < p->size);
- /* no trailing dot */
- if (!*name)
- break;
+ if (index < 0x4000) {
+ guint16 *t;
+ if (!(t = (guint16*) flx_dns_packet_extend(p, sizeof(guint16))))
+ return NULL;
- name ++;
+ *t = g_htons((0xC000 | index));
+ return saved_ptr;
+ }
+ }
- /* trailing dot */
- if (!*name)
- break;
+ pname = name;
+
+ if (!(unescape_label(label, sizeof(label), &name)))
+ goto fail;
+
+ if (!(d = flx_dns_packet_append_string(p, label)))
+ goto fail;
+
+ if (!p->name_table)
+ p->name_table = g_hash_table_new_full((GHashFunc) flx_domain_hash, (GEqualFunc) flx_domain_equal, g_free, NULL);
+
+ g_hash_table_insert(p->name_table, g_strdup(pname), d);
}
if (!(d = flx_dns_packet_extend(p, 1)))
goto fail;
- d[0] = 0;
+ *d = 0;
- return f;
+ return saved_ptr;
fail:
p->size = saved_size;
g_assert(p);
g_assert(b);
g_assert(l);
-
+
if (!(d = flx_dns_packet_extend(p, l)))
return NULL;
return d;
}
+guint8* flx_dns_packet_append_string(flxDnsPacket *p, const gchar *s) {
+ guint8* d;
+ guint k;
+
+ g_assert(p);
+ g_assert(s);
+
+ if ((k = strlen(s)) >= 255)
+ k = 255;
+
+ if (!(d = flx_dns_packet_extend(p, k+1)))
+ return NULL;
+
+ *d = (guint8) k;
+ memcpy(d+1, s, k);
+
+ return d;
+}
+
guint8 *flx_dns_packet_extend(flxDnsPacket *p, guint l) {
guint8 *d;
return d;
}
-guint8 *flx_dns_packet_append_name_compressed(flxDnsPacket *p, const gchar *name, guint8 *prev) {
- guint16 *d;
- signed long k;
- g_assert(p);
-
- if (!prev)
- return flx_dns_packet_append_name(p, name);
-
- k = prev - FLX_DNS_PACKET_DATA(p);
- if (k < 0 || k >= 0x4000 || (guint) k >= p->size)
- return flx_dns_packet_append_name(p, name);
-
- if (!(d = (guint16*) flx_dns_packet_extend(p, sizeof(guint16))))
- return NULL;
-
- *d = g_htons((0xC000 | k));
- return prev;
-}
-
gint flx_dns_packet_check_valid(flxDnsPacket *p) {
guint16 flags;
g_assert(p);
if (p->size < 12)
return -1;
- flags = flx_dns_packet_get_field(p, DNS_FIELD_FLAGS);
+ flags = flx_dns_packet_get_field(p, FLX_DNS_FIELD_FLAGS);
- if (flags & DNS_FLAG_OPCODE || flags & DNS_FLAG_RCODE)
+ if (flags & FLX_DNS_FLAG_OPCODE || flags & FLX_DNS_FLAG_RCODE)
return -1;
return 0;
gint flx_dns_packet_is_query(flxDnsPacket *p) {
g_assert(p);
- return !(flx_dns_packet_get_field(p, DNS_FIELD_FLAGS) & DNS_FLAG_QR);
+ return !(flx_dns_packet_get_field(p, FLX_DNS_FIELD_FLAGS) & FLX_DNS_FLAG_QR);
+}
+
+/* Read a label from a DNS packet, escape "\" and ".", append \0 */
+static gchar *escape_label(guint8* src, guint src_length, gchar **ret_name, guint *ret_name_length) {
+ gchar *r;
+
+ g_assert(src);
+ g_assert(ret_name);
+ g_assert(*ret_name);
+ g_assert(ret_name_length);
+ g_assert(*ret_name_length > 0);
+
+ r = *ret_name;
+
+ while (src_length > 0) {
+ if (*src == '.' || *src == '\\') {
+ if (*ret_name_length < 3)
+ return NULL;
+
+ *((*ret_name) ++) = '\\';
+ (*ret_name_length) --;
+ }
+
+ if (*ret_name_length < 2)
+ return NULL;
+
+ *((*ret_name)++) = *src;
+ (*ret_name_length) --;
+
+ src_length --;
+ src++;
+ }
+
+ **ret_name = 0;
+
+ return r;
}
static gint consume_labels(flxDnsPacket *p, guint index, gchar *ret_name, guint l) {
} else
first_label = 0;
- memcpy(ret_name, FLX_DNS_PACKET_DATA(p) + index, n);
+ if (!(escape_label(FLX_DNS_PACKET_DATA(p) + index, n, &ret_name, &l)))
+ return -1;
+
index += n;
- ret_name += n;
- l -= n;
if (!compressed)
ret += n;
return 0;
}
+gint flx_dns_packet_consume_string(flxDnsPacket *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 = FLX_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, FLX_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
+ ret_string[l-1] = 0;
+
+
+ p->rindex += 1+k;
+
+ return 0;
+
+}
+
gconstpointer flx_dns_packet_get_rptr(flxDnsPacket *p) {
g_assert(p);
- if (p->rindex >= p->size)
+ if (p->rindex > p->size)
return NULL;
return FLX_DNS_PACKET_DATA(p) + p->rindex;
}
flxRecord* flx_dns_packet_consume_record(flxDnsPacket *p, gboolean *ret_cache_flush) {
- gchar name[256];
+ gchar name[257], buf[257];
guint16 type, class;
guint32 ttl;
guint16 rdlength;
gconstpointer data;
+ flxRecord *r = NULL;
+ gconstpointer start;
g_assert(p);
g_assert(ret_cache_flush);
+/* g_message("consume_record()"); */
+
if (flx_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
flx_dns_packet_consume_uint16(p, &type) < 0 ||
flx_dns_packet_consume_uint16(p, &class) < 0 ||
flx_dns_packet_consume_uint32(p, &ttl) < 0 ||
flx_dns_packet_consume_uint16(p, &rdlength) < 0 ||
- !(data = flx_dns_packet_get_rptr(p)) ||
- flx_dns_packet_skip(p, rdlength) < 0)
- return NULL;
+ p->rindex + rdlength > p->size)
+
+ goto fail;
+
+/* g_message("name = %s, rdlength = %u", name, rdlength); */
+
+ start = flx_dns_packet_get_rptr(p);
+
+ r = flx_record_new_full(name, class, type);
+
+ switch (type) {
+ case FLX_DNS_TYPE_PTR:
+ case FLX_DNS_TYPE_CNAME:
+
+/* g_message("ptr"); */
+
+ if (flx_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
+ goto fail;
- *ret_cache_flush = !!(class & MDNS_CACHE_FLUSH);
- class &= ~ MDNS_CACHE_FLUSH;
+ r->data.ptr.name = g_strdup(buf);
+ break;
+
+
+ case FLX_DNS_TYPE_SRV:
- return flx_record_new_full(name, class, type, data, rdlength, ttl);
+/* g_message("srv"); */
+
+ if (flx_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
+ flx_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
+ flx_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
+ flx_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
+ goto fail;
+
+ r->data.srv.name = g_strdup(buf);
+ break;
+
+ case FLX_DNS_TYPE_HINFO:
+
+/* g_message("hinfo"); */
+
+ if (flx_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
+ goto fail;
+
+ r->data.hinfo.cpu = g_strdup(buf);
+
+ if (flx_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
+ goto fail;
+
+ r->data.hinfo.os = g_strdup(buf);
+ break;
+
+ case FLX_DNS_TYPE_TXT:
+
+/* g_message("txt"); */
+
+ if (rdlength > 0) {
+ r->data.txt.string_list = flx_string_list_parse(flx_dns_packet_get_rptr(p), rdlength);
+
+ if (flx_dns_packet_skip(p, rdlength) < 0)
+ goto fail;
+ } else
+ r->data.txt.string_list = NULL;
+
+ break;
+
+ case FLX_DNS_TYPE_A:
+
+/* g_message("A"); */
+
+ if (flx_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(flxIPv4Address)) < 0)
+ goto fail;
+
+ break;
+
+ case FLX_DNS_TYPE_AAAA:
+
+/* g_message("aaaa"); */
+
+ if (flx_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(flxIPv6Address)) < 0)
+ goto fail;
+
+ break;
+
+ default:
+
+/* g_message("generic"); */
+
+ if (rdlength > 0) {
+
+ r->data.generic.data = g_memdup(flx_dns_packet_get_rptr(p), rdlength);
+
+ if (flx_dns_packet_skip(p, rdlength) < 0)
+ goto fail;
+ }
+
+ break;
+ }
+
+/* g_message("%i == %u ?", (guint8*) flx_dns_packet_get_rptr(p) - (guint8*) start, rdlength); */
+
+ /* Check if we read enough data */
+ if ((guint8*) flx_dns_packet_get_rptr(p) - (guint8*) start != rdlength)
+ goto fail;
+
+ *ret_cache_flush = !!(class & FLX_DNS_CACHE_FLUSH);
+ class &= ~ FLX_DNS_CACHE_FLUSH;
+
+ r->ttl = ttl;
+
+ return r;
+
+fail:
+ if (r)
+ flx_record_unref(r);
+
+ return NULL;
}
flxKey* flx_dns_packet_consume_key(flxDnsPacket *p) {
flx_dns_packet_consume_uint16(p, &class) < 0)
return NULL;
- class &= ~ MDNS_CACHE_FLUSH;
+ class &= ~ FLX_DNS_CACHE_FLUSH;
return flx_key_new(name, class, type);
}
guint8* flx_dns_packet_append_key(flxDnsPacket *p, flxKey *k) {
guint8 *t;
+ guint size;
g_assert(p);
g_assert(k);
+ size = p->size;
+
if (!(t = flx_dns_packet_append_name(p, k->name)) ||
!flx_dns_packet_append_uint16(p, k->type) ||
- !flx_dns_packet_append_uint16(p, k->class))
+ !flx_dns_packet_append_uint16(p, k->class)) {
+ p->size = size;
return NULL;
+ }
return t;
}
guint8* flx_dns_packet_append_record(flxDnsPacket *p, flxRecord *r, gboolean cache_flush) {
- guint8 *t;
+ guint8 *t, *l, *start;
+ guint size;
g_assert(p);
g_assert(r);
+ size = p->size;
+
if (!(t = flx_dns_packet_append_name(p, r->key->name)) ||
!flx_dns_packet_append_uint16(p, r->key->type) ||
- !flx_dns_packet_append_uint16(p, cache_flush ? (r->key->class | MDNS_CACHE_FLUSH) : (r->key->class &~ MDNS_CACHE_FLUSH)) ||
+ !flx_dns_packet_append_uint16(p, cache_flush ? (r->key->class | FLX_DNS_CACHE_FLUSH) : (r->key->class &~ FLX_DNS_CACHE_FLUSH)) ||
!flx_dns_packet_append_uint32(p, r->ttl) ||
- !flx_dns_packet_append_uint16(p, r->size) ||
- !flx_dns_packet_append_bytes(p, r->data, r->size))
- return NULL;
+ !(l = flx_dns_packet_append_uint16(p, 0)))
+ goto fail;
+
+ start = flx_dns_packet_extend(p, 0);
+
+ switch (r->key->type) {
+
+ case FLX_DNS_TYPE_PTR:
+ case FLX_DNS_TYPE_CNAME :
+
+ if (!(flx_dns_packet_append_name(p, r->data.ptr.name)))
+ goto fail;
+
+ break;
+
+ case FLX_DNS_TYPE_SRV:
+
+ if (!flx_dns_packet_append_uint16(p, r->data.srv.priority) ||
+ !flx_dns_packet_append_uint16(p, r->data.srv.weight) ||
+ !flx_dns_packet_append_uint16(p, r->data.srv.port) ||
+ !flx_dns_packet_append_name(p, r->data.srv.name))
+ goto fail;
+
+ break;
+
+ case FLX_DNS_TYPE_HINFO:
+ if (!flx_dns_packet_append_string(p, r->data.hinfo.cpu) ||
+ !flx_dns_packet_append_string(p, r->data.hinfo.os))
+ goto fail;
+
+ break;
+
+ case FLX_DNS_TYPE_TXT: {
+
+ guint8 *data;
+ guint size;
+ size = flx_string_list_serialize(r->data.txt.string_list, NULL, 0);
+
+/* g_message("appending string: %u %p", size, r->data.txt.string_list); */
+
+ if (!(data = flx_dns_packet_extend(p, size)))
+ goto fail;
+
+ flx_string_list_serialize(r->data.txt.string_list, data, size);
+ break;
+ }
+
+
+ case FLX_DNS_TYPE_A:
+
+ if (!flx_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
+ goto fail;
+
+ break;
+
+ case FLX_DNS_TYPE_AAAA:
+
+ if (!flx_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
+ goto fail;
+
+ break;
+
+ default:
+
+ if (r->data.generic.size &&
+ flx_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
+ goto fail;
+
+ break;
+ }
+
+
+
+
+ size = flx_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 flx_dns_packet_is_empty(flxDnsPacket *p) {
+ g_assert(p);
+
+ return p->size <= FLX_DNS_PACKET_HEADER_SIZE;
+}
+
+guint flx_dns_packet_space(flxDnsPacket *p) {
+ g_assert(p);
+
+ g_assert(p->size <= p->max_size);
+
+ return p->max_size - p->size;
}
projects / catta / blobdiff