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-rw-r--r--src/plugins/dns/dns_packet.h156
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+/*
+ * Copyright (c) 2015 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef included_dns_packet_h
+#define included_dns_packet_h
+
+/**
+ * DNS packet header format
+ */
+
+/* *INDENT-OFF* */
+typedef CLIB_PACKED (struct {
+ u16 id; /**< transaction ID */
+ u16 flags; /**< flags */
+ u16 qdcount; /**< number of questions */
+ u16 anscount; /**< number of answers */
+ u16 nscount; /**< number of name servers */
+ u16 arcount; /**< number of additional records */
+}) dns_header_t;
+/* *INDENT-ON* */
+
+#define DNS_RCODE_MASK (0xf)
+#define DNS_RCODE_NO_ERROR 0
+#define DNS_RCODE_FORMAT_ERROR 1
+#define DNS_RCODE_SERVER_FAILURE 2
+#define DNS_RCODE_NAME_ERROR 3
+#define DNS_RCODE_NOT_IMPLEMENTED 4
+#define DNS_RCODE_REFUSED 5
+
+#define DNS_RA (1<<7) /**< recursion available */
+#define DNS_RD (1<<8) /**< recursion desired */
+#define DNS_TC (1<<9) /**< truncation */
+#define DNS_AA (1<<10) /**< authoritative answer */
+#define DNS_OPCODE_MASK (0xf<<11) /**< opcode mask */
+#define DNS_OPCODE_QUERY (0<<11) /**< standard query */
+#define DNS_OPCODE_IQUERY (1<<11) /**< inverse query (deprecated) */
+#define DNS_OPCODE_STATUS (2<<11) /**< server status */
+#define DNS_QR (1<<15) /**< query=0, response=1 */
+
+
+/*
+ * Note: in DNS-land, www.foobar.com is encoded as three "labels,"
+ * each of which amount to a 1 octet length followed by up to 63
+ * octets of name. Don't forget to add a "null root label" after the last
+ * real one, or the poor slob trying to parse the name will have
+ * no chance whatsoever.
+ *
+ * All RRs have the same top level format shown below:
+ *
+ * 1 1 1 1 1 1
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ * | |
+ * / /
+ * / NAME /
+ * | |
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ * | TYPE |
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ * | CLASS |
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ * | TTL |
+ * | |
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ * | RDLENGTH |
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
+ * / RDATA /
+ * / /
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ *
+ *
+ * DNS "questions" have the following format:
+ *
+ * 1 1 1 1 1 1
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ * | |
+ * / QNAME /
+ * / /
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ * | QTYPE |
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ * | QCLASS |
+ * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+ */
+
+/**
+ * DNS "question" fixed header.
+ */
+/* *INDENT-OFF* */
+typedef CLIB_PACKED (struct {
+ u16 type; /**< record type requested */
+ u16 class; /**< class, 1 = internet */
+}) dns_query_t;
+/* *INDENT-ON* */
+
+/**
+ * DNS RR fixed header.
+ */
+/* *INDENT-OFF* */
+typedef CLIB_PACKED (struct {
+ u16 type; /**< record type */
+ u16 class; /**< class, 1 = internet */
+ u32 ttl; /**< time to live, in seconds */
+ u16 rdlength;
+ /**< length of r */
+ u8 rdata[0];
+}) dns_rr_t;
+/* *INDENT-ON* */
+
+/*
+ * There are quite a number of DNS record types
+ * Feel free to add as needed
+ */
+#define foreach_dns_type \
+_(A, 1) /**< ip4 host address */ \
+_(AAAA, 28) /**< ip6 host address */ \
+_(ALL, 255) /**< all available data */ \
+_(TEXT, 16) /**< a text string */ \
+_(NAMESERVER, 2) /**< a nameserver */ \
+_(CNAME, 5) /**< a CNAME (alias) */ \
+_(MAIL_EXCHANGE, 15) /**< a mail exchange */ \
+_(PTR, 12) /**< a PTR (pointer) record */ \
+_(HINFO, 13) /**< Host info */
+
+typedef enum
+{
+#define _(name,value) DNS_TYPE_##name = value,
+ foreach_dns_type
+#undef _
+} dns_type_t;
+
+#define DNS_CLASS_IN 1 /**< The Internet */
+
+
+#endif /* included_dns_packet_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */