X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=avahi-core%2Fdns.c;h=41d645f952944ee393d4a819d19101a64909db21;hb=22a61b042376903deada022e7585e0585aaa7d43;hp=cc1463a729b15ea66702bedd2e1134ccfeb4ba9e;hpb=c58379bde376cb2298fca14f83a86626f1b76f2f;p=catta diff --git a/avahi-core/dns.c b/avahi-core/dns.c index cc1463a..41d645f 100644 --- a/avahi-core/dns.c +++ b/avahi-core/dns.c @@ -32,12 +32,18 @@ #include "dns.h" #include "util.h" -AvahiDnsPacket* avahi_dns_packet_new(guint max_size) { +AvahiDnsPacket* avahi_dns_packet_new(guint mtu) { AvahiDnsPacket *p; + guint max_size; - if (max_size <= 0) + if (mtu <= 0) max_size = AVAHI_DNS_PACKET_MAX_SIZE; - else if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE) + else if (mtu >= 48) + max_size = mtu - 48; + 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); @@ -49,22 +55,59 @@ AvahiDnsPacket* avahi_dns_packet_new(guint max_size) { return p; } -AvahiDnsPacket* avahi_dns_packet_new_query(guint max_size) { +AvahiDnsPacket* avahi_dns_packet_new_query(guint mtu) { AvahiDnsPacket *p; - p = avahi_dns_packet_new(max_size); + 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 max_size) { +AvahiDnsPacket* avahi_dns_packet_new_response(guint mtu, gboolean aa) { AvahiDnsPacket *p; - p = avahi_dns_packet_new(max_size); - avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, 0, 0, 0, 0, 0, 0, 0, 0)); + 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); @@ -88,47 +131,13 @@ guint16 avahi_dns_packet_get_field(AvahiDnsPacket *p, guint index) { return g_ntohs(((guint16*) AVAHI_DNS_PACKET_DATA(p))[index]); } -/* Read the first label from string *name, unescape "\" and write it to dest */ -gchar *avahi_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++; - } +void avahi_dns_packet_inc_field(AvahiDnsPacket *p, guint index) { + g_assert(p); - g_assert(i < size); + avahi_dns_packet_set_field(p, index, avahi_dns_packet_get_field(p, index) + 1); +} - *d = 0; - return dest; -} guint8* avahi_dns_packet_append_name(AvahiDnsPacket *p, const gchar *name) { guint8 *d, *saved_ptr = NULL; @@ -167,14 +176,15 @@ guint8* avahi_dns_packet_append_name(AvahiDnsPacket *p, const gchar *name) { pname = name; - if (!(avahi_unescape_label(label, sizeof(label), &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) - p->name_table = g_hash_table_new_full((GHashFunc) avahi_domain_hash, (GEqualFunc) avahi_domain_equal, g_free, NULL); + /* 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); } @@ -282,42 +292,6 @@ gint avahi_dns_packet_is_query(AvahiDnsPacket *p) { return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_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(AvahiDnsPacket *p, guint index, gchar *ret_name, guint l) { gint ret = 0; int compressed = 0; @@ -361,7 +335,7 @@ static gint consume_labels(AvahiDnsPacket *p, guint index, gchar *ret_name, guin } else first_label = 0; - if (!(escape_label(AVAHI_DNS_PACKET_DATA(p) + index, n, &ret_name, &l))) + if (!(avahi_escape_label(AVAHI_DNS_PACKET_DATA(p) + index, n, &ret_name, &l))) return -1; index += n; @@ -654,7 +628,7 @@ guint8* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, gboolean uni return t; } -guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush) { +guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush, guint max_ttl) { guint8 *t, *l, *start; guint size; @@ -666,7 +640,7 @@ guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboole 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, r->ttl) || + !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;