return g_ntohs(((guint16*) FLX_DNS_PACKET_DATA(p))[index]);
}
+/* Read the first label from string *name, unescape "\" and write it to dest */
+gchar *flx_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;
-
- for (;;) {
+ saved_ptr = flx_dns_packet_extend(p, 0);
+
+ while (*name) {
guint n;
guint8* prev;
+ const gchar *pname;
+ gchar label[64];
/* Check whether we can compress this name. */
if (!(t = (guint16*) flx_dns_packet_extend(p, sizeof(guint16))))
return NULL;
- if (!f)
- f = (guint8*) t;
-
*t = g_htons((0xC000 | index));
- return f;
+ return saved_ptr;
}
}
+
+ pname = name;
- n = strcspn(name, ".");
- if (!n || n > 63)
+ if (!(flx_unescape_label(label, sizeof(label), &name)))
goto fail;
-
- if (!(d = flx_dns_packet_extend(p, n+1)))
+
+ if (!(d = flx_dns_packet_append_string(p, label)))
goto fail;
-
- if (!f)
- f = d;
- d[0] = n;
- memcpy(d+1, name, n);
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(name), d);
-
- name += n;
-
- /* no trailing dot */
- if (!*name)
- break;
-
- name ++;
-
- /* trailing dot */
- if (!*name)
- break;
+ 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;
return NULL;
}
-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;
-}
-
guint8* flx_dns_packet_append_uint16(flxDnsPacket *p, guint16 v) {
guint8 *d;
g_assert(p);
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) {
gint ret = 0;
int compressed = 0;
} 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;
goto fail;
/* g_message("name = %s, rdlength = %u", name, rdlength); */
+
+ *ret_cache_flush = !!(class & FLX_DNS_CACHE_FLUSH);
+ class &= ~ FLX_DNS_CACHE_FLUSH;
start = flx_dns_packet_get_rptr(p);
-
+
r = flx_record_new_full(name, class, type);
switch (type) {
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;