diff options
Diffstat (limited to 'dns.c')
| -rw-r--r-- | dns.c | 256 |
1 files changed, 213 insertions, 43 deletions
@@ -1,3 +1,5 @@ +#include <netinet/in.h> + #include <stdlib.h> #include <string.h> #include <stdio.h> @@ -139,6 +141,25 @@ guint8 *flx_dns_packet_append_bytes(flxDnsPacket *p, gconstpointer b, guint l) 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; @@ -310,10 +331,38 @@ gint flx_dns_packet_consume_bytes(flxDnsPacket *p, gpointer ret_data, guint l) { 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; @@ -330,65 +379,144 @@ gint flx_dns_packet_skip(flxDnsPacket *p, guint length) { } flxRecord* flx_dns_packet_consume_record(flxDnsPacket *p, gboolean *ret_cache_flush) { - gchar name[257], buf[257+6]; + 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) - return NULL; + flx_dns_packet_consume_uint16(p, &rdlength) < 0 || + 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) - return NULL; + goto fail; + + r->data.ptr.name = g_strdup(buf); + break; + - data = buf; - rdlength = strlen(buf); + case FLX_DNS_TYPE_SRV: + + 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_SRV: { - const guint8 *t = flx_dns_packet_get_rptr(p); + case FLX_DNS_TYPE_TXT: + + g_message("txt"); - if (flx_dns_packet_skip(p, 6) < 0) - return NULL; + 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; + } - memcpy(buf, t, 6); + break; + + case FLX_DNS_TYPE_A: + + g_message("A"); - if (flx_dns_packet_consume_name(p, buf+6, sizeof(buf)-6) < 0) - return NULL; - data = buf; - rdlength = 6 + strlen(buf+6); + g_message("%p", flx_dns_packet_get_rptr(p)); + + if (flx_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(flxIPv4Address)) < 0) + goto fail; + + g_message("%p", flx_dns_packet_get_rptr(p)); + + 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) { - if (!(data = flx_dns_packet_get_rptr(p)) || - flx_dns_packet_skip(p, rdlength) < 0) - return NULL; - } else - data = NULL; + 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 & MDNS_CACHE_FLUSH); class &= ~ MDNS_CACHE_FLUSH; - return flx_record_new_full(name, class, type, data, rdlength, ttl); + r->ttl = ttl; + + return r; + +fail: + if (r) + flx_record_unref(r); + + return NULL; } flxKey* flx_dns_packet_consume_key(flxDnsPacket *p) { @@ -427,7 +555,7 @@ guint8* flx_dns_packet_append_key(flxDnsPacket *p, flxKey *k) { } guint8* flx_dns_packet_append_record(flxDnsPacket *p, flxRecord *r, gboolean cache_flush) { - guint8 *t; + guint8 *t, *l, *start; guint size; g_assert(p); @@ -438,47 +566,89 @@ guint8* flx_dns_packet_append_record(flxDnsPacket *p, flxRecord *r, gboolean cac 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)) + !flx_dns_packet_append_uint32(p, r->ttl) || + !(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: { - char ptr_name[257]; + case FLX_DNS_TYPE_CNAME : - 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_name(p, r->data.ptr.name))) + goto fail; - if (!flx_dns_packet_append_uint16(p, strlen(ptr_name)+1) || - !flx_dns_packet_append_name(p, ptr_name)) + 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_SRV: { - char name[257]; + 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; - 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; + size = flx_string_list_serialize(r->data.txt.string_list, NULL, 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)) + 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 (!flx_dns_packet_append_uint16(p, r->size) || - (r->size != 0 && !flx_dns_packet_append_bytes(p, r->data, r->size))) + + 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; |