#include "dns.h"
-flxDnsPacket* flx_dns_packet_new(void) {
+flxDnsPacket* flx_dns_packet_new(guint max_size) {
flxDnsPacket *p;
- p = g_new(flxDnsPacket, 1);
- p->size = p->rindex = 2*6;
- memset(p->data, 0, p->size);
+
+ if (max_size <= 0)
+ max_size = FLX_DNS_PACKET_MAX_SIZE;
+ else if (max_size < FLX_DNS_PACKET_HEADER_SIZE)
+ max_size = FLX_DNS_PACKET_HEADER_SIZE;
+
+ p = g_malloc(sizeof(flxDnsPacket) + max_size);
+ p->size = p->rindex = FLX_DNS_PACKET_HEADER_SIZE;
+ p->max_size = max_size;
+
+ memset(FLX_DNS_PACKET_DATA(p), 0, p->size);
+ return p;
+}
+
+flxDnsPacket* flx_dns_packet_new_query(guint max_size) {
+ 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));
+ return p;
+}
+
+flxDnsPacket* flx_dns_packet_new_response(guint max_size) {
+ 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));
return p;
}
void flx_dns_packet_set_field(flxDnsPacket *p, guint index, guint16 v) {
g_assert(p);
- g_assert(index < 2*6);
+ g_assert(index < FLX_DNS_PACKET_HEADER_SIZE);
- ((guint16*) p->data)[index] = g_htons(v);
+ ((guint16*) FLX_DNS_PACKET_DATA(p))[index] = g_htons(v);
}
guint16 flx_dns_packet_get_field(flxDnsPacket *p, guint index) {
g_assert(p);
- g_assert(index < 2*6);
+ g_assert(index < FLX_DNS_PACKET_HEADER_SIZE);
- return g_ntohs(((guint16*) p->data)[index]);
+ return g_ntohs(((guint16*) FLX_DNS_PACKET_DATA(p))[index]);
}
guint8* flx_dns_packet_append_name(flxDnsPacket *p, const gchar *name) {
guint8 *d, *f = NULL;
+ guint saved_size;
g_assert(p);
g_assert(name);
+ saved_size = p->size;
+
for (;;) {
guint n = strcspn(name, ".");
if (!n || n > 63)
- return NULL;
+ goto fail;
- d = flx_dns_packet_extend(p, n+1);
+ if (!(d = flx_dns_packet_extend(p, n+1)))
+ goto fail;
+
if (!f)
f = d;
d[0] = n;
break;
}
- d = flx_dns_packet_extend(p, 1);
+ if (!(d = flx_dns_packet_extend(p, 1)))
+ goto fail;
+
d[0] = 0;
return f;
+
+fail:
+ p->size = saved_size;
+ return NULL;
}
guint8* flx_dns_packet_append_uint16(flxDnsPacket *p, guint16 v) {
guint8 *d;
-
g_assert(p);
- d = flx_dns_packet_extend(p, sizeof(guint16));
+ if (!(d = flx_dns_packet_extend(p, sizeof(guint16))))
+ return NULL;
+
*((guint16*) d) = g_htons(v);
+ return d;
+}
+
+guint8 *flx_dns_packet_append_uint32(flxDnsPacket *p, guint32 v) {
+ guint8 *d;
+ g_assert(p);
+
+ if (!(d = flx_dns_packet_extend(p, sizeof(guint32))))
+ return NULL;
+ *((guint32*) d) = g_htonl(v);
+
+ return d;
+}
+
+guint8 *flx_dns_packet_append_bytes(flxDnsPacket *p, gconstpointer b, guint l) {
+ guint8* d;
+
+ g_assert(p);
+ g_assert(b);
+ g_assert(l);
+
+ if (!(d = flx_dns_packet_extend(p, l)))
+ return NULL;
+
+ memcpy(d, b, l);
return d;
}
guint8 *d;
g_assert(p);
- g_assert(p->size+l <= sizeof(p->data));
- d = p->data + p->size;
+ if (p->size+l > p->max_size)
+ return NULL;
+
+ d = FLX_DNS_PACKET_DATA(p) + p->size;
p->size += l;
return d;
if (!prev)
return flx_dns_packet_append_name(p, name);
- k = prev - p->data;
+ k = prev - FLX_DNS_PACKET_DATA(p);
if (k < 0 || k >= 0x4000 || (guint) k >= p->size)
return flx_dns_packet_append_name(p, name);
- d = (guint16*) flx_dns_packet_extend(p, sizeof(guint16));
- *d = g_htons((0xC000 | k));
+ if (!(d = (guint16*) flx_dns_packet_extend(p, sizeof(guint16))))
+ return NULL;
+ *d = g_htons((0xC000 | k));
return prev;
}
if (index+1 > p->size)
return -1;
- n = p->data[index];
+ n = FLX_DNS_PACKET_DATA(p)[index];
if (!n) {
index++;
} else
first_label = 0;
- memcpy(ret_name, p->data + index, n);
+ memcpy(ret_name, FLX_DNS_PACKET_DATA(p) + index, n);
index += n;
ret_name += n;
l -= n;
if (index+2 > p->size)
return -1;
- index = ((guint) (p->data[index] & ~0xC0)) << 8 | p->data[index+1];
+ index = ((guint) (FLX_DNS_PACKET_DATA(p)[index] & ~0xC0)) << 8 | FLX_DNS_PACKET_DATA(p)[index+1];
if (!compressed)
ret += 2;
if (p->rindex + sizeof(guint16) > p->size)
return -1;
- *ret_v = g_ntohs(*((guint16*) (p->data + p->rindex)));
+ *ret_v = g_ntohs(*((guint16*) (FLX_DNS_PACKET_DATA(p) + p->rindex)));
p->rindex += sizeof(guint16);
return 0;
if (p->rindex + sizeof(guint32) > p->size)
return -1;
- *ret_v = g_ntohl(*((guint32*) (p->data + p->rindex)));
+ *ret_v = g_ntohl(*((guint32*) (FLX_DNS_PACKET_DATA(p) + p->rindex)));
p->rindex += sizeof(guint32);
return 0;
if (p->rindex + l > p->size)
return -1;
- memcpy(ret_data, p->data + p->rindex, l);
+ memcpy(ret_data, FLX_DNS_PACKET_DATA(p) + p->rindex, l);
p->rindex += l;
return 0;
if (p->rindex >= p->size)
return NULL;
- return p->data + p->rindex;
+ return FLX_DNS_PACKET_DATA(p) + p->rindex;
}
gint flx_dns_packet_skip(flxDnsPacket *p, guint length) {
}
flxRecord* flx_dns_packet_consume_record(flxDnsPacket *p, gboolean *ret_cache_flush) {
- gchar name[256];
+ gchar name[257], buf[257+6];
guint16 type, class;
guint32 ttl;
guint16 rdlength;
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)
+ flx_dns_packet_consume_uint16(p, &rdlength) < 0)
return NULL;
+ switch (type) {
+ case FLX_DNS_TYPE_PTR:
+ case FLX_DNS_TYPE_CNAME:
+ if (flx_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
+ return NULL;
+
+ data = buf;
+ rdlength = strlen(buf);
+ break;
+
+ case FLX_DNS_TYPE_SRV: {
+ const guint8 *t = flx_dns_packet_get_rptr(p);
+
+ if (flx_dns_packet_skip(p, 6) < 0)
+ return NULL;
+
+ memcpy(buf, t, 6);
+
+ if (flx_dns_packet_consume_name(p, buf+6, sizeof(buf)-6) < 0)
+ return NULL;
+
+ data = buf;
+ rdlength = 6 + strlen(buf+6);
+ break;
+ }
+
+ default:
+
+ if (rdlength > 0) {
+
+ if (!(data = flx_dns_packet_get_rptr(p)) ||
+ flx_dns_packet_skip(p, rdlength) < 0)
+ return NULL;
+ } else
+ data = NULL;
+
+ break;
+ }
+
*ret_cache_flush = !!(class & MDNS_CACHE_FLUSH);
class &= ~ MDNS_CACHE_FLUSH;
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;
+ 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_uint32(p, r->ttl))
+ goto fail;
+
+ switch (r->key->type) {
+
+ case FLX_DNS_TYPE_PTR:
+ case FLX_DNS_TYPE_CNAME: {
+ char ptr_name[257];
+
+ g_assert((size_t) r->size+1 <= sizeof(ptr_name));
+ memcpy(ptr_name, r->data, r->size);
+ ptr_name[r->size] = 0;
+
+ if (!flx_dns_packet_append_uint16(p, strlen(ptr_name)+1) ||
+ !flx_dns_packet_append_name(p, ptr_name))
+ goto fail;
+
+ break;
+ }
+
+ case FLX_DNS_TYPE_SRV: {
+ char name[257];
+
+ g_assert(r->size >= 6 && (size_t) r->size-6+1 <= sizeof(name));
+ memcpy(name, r->data+6, r->size-6);
+ name[r->size-6] = 0;
+
+ if (!flx_dns_packet_append_uint16(p, strlen(name+6)+1+6) ||
+ !flx_dns_packet_append_bytes(p, r->data, 6) ||
+ !flx_dns_packet_append_name(p, name))
+ goto fail;
+
+ break;
+ }
+
+ default:
+ if (!flx_dns_packet_append_uint16(p, r->size) ||
+ (r->size != 0 && !flx_dns_packet_append_bytes(p, r->data, r->size)))
+ goto fail;
+ }
+
+ 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;
}
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