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Diffstat (limited to 'pjlib-util/include/pjlib-util/dns.h')
| -rw-r--r-- | pjlib-util/include/pjlib-util/dns.h | 445 |
1 files changed, 445 insertions, 0 deletions
diff --git a/pjlib-util/include/pjlib-util/dns.h b/pjlib-util/include/pjlib-util/dns.h new file mode 100644 index 0000000..99c5bd8 --- /dev/null +++ b/pjlib-util/include/pjlib-util/dns.h @@ -0,0 +1,445 @@ +/* $Id: dns.h 3553 2011-05-05 06:14:19Z nanang $ */ +/* + * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) + * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +#ifndef __PJLIB_UTIL_DNS_H__ +#define __PJLIB_UTIL_DNS_H__ + + +/** + * @file dns.h + * @brief Low level DNS message parsing and packetization. + */ +#include <pjlib-util/types.h> +#include <pj/sock.h> + +PJ_BEGIN_DECL + +/** + * @defgroup PJ_DNS DNS and Asynchronous DNS Resolver + * @ingroup PJ_PROTOCOLS + */ + +/** + * @defgroup PJ_DNS_PARSING Low-level DNS Message Parsing and Packetization + * @ingroup PJ_DNS + * @{ + * + * This module provides low-level services to parse and packetize DNS queries + * and responses. The functions support building a DNS query packet and parse + * the data in the DNS response. This implementation conforms to the + * following specifications: + * - RFC 1035: DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION + * - RFC 1886: DNS Extensions to support IP version 6 + * + * To create a DNS query packet, application should call #pj_dns_make_query() + * function, specifying the desired DNS query type, the name to be resolved, + * and the buffer where the DNS packet will be built into. + * + * When incoming DNS query or response packet arrives, application can use + * #pj_dns_parse_packet() to parse the TCP/UDP payload into parsed DNS packet + * structure. + * + * This module does not provide any networking functionalities to send or + * receive DNS packets. This functionality should be provided by higher layer + * modules such as @ref PJ_DNS_RESOLVER. + */ + +enum +{ + PJ_DNS_CLASS_IN = 1 /**< DNS class IN. */ +}; + +/** + * This enumeration describes standard DNS record types as described by + * RFC 1035, RFC 2782, and others. + */ +typedef enum pj_dns_type +{ + PJ_DNS_TYPE_A = 1, /**< Host address (A) record. */ + PJ_DNS_TYPE_NS = 2, /**< Authoritative name server (NS) */ + PJ_DNS_TYPE_MD = 3, /**< Mail destination (MD) record. */ + PJ_DNS_TYPE_MF = 4, /**< Mail forwarder (MF) record. */ + PJ_DNS_TYPE_CNAME = 5, /**< Canonical name (CNAME) record. */ + PJ_DNS_TYPE_SOA = 6, /**< Marks start of zone authority. */ + PJ_DNS_TYPE_MB = 7, /**< Mailbox domain name (MB). */ + PJ_DNS_TYPE_MG = 8, /**< Mail group member (MG). */ + PJ_DNS_TYPE_MR = 9, /**< Mail rename domain name. */ + PJ_DNS_TYPE_NULL = 10, /**< NULL RR. */ + PJ_DNS_TYPE_WKS = 11, /**< Well known service description */ + PJ_DNS_TYPE_PTR = 12, /**< Domain name pointer. */ + PJ_DNS_TYPE_HINFO = 13, /**< Host information. */ + PJ_DNS_TYPE_MINFO = 14, /**< Mailbox or mail list information. */ + PJ_DNS_TYPE_MX = 15, /**< Mail exchange record. */ + PJ_DNS_TYPE_TXT = 16, /**< Text string. */ + PJ_DNS_TYPE_RP = 17, /**< Responsible person. */ + PJ_DNS_TYPE_AFSB = 18, /**< AFS cell database. */ + PJ_DNS_TYPE_X25 = 19, /**< X.25 calling address. */ + PJ_DNS_TYPE_ISDN = 20, /**< ISDN calling address. */ + PJ_DNS_TYPE_RT = 21, /**< Router. */ + PJ_DNS_TYPE_NSAP = 22, /**< NSAP address. */ + PJ_DNS_TYPE_NSAP_PTR= 23, /**< NSAP reverse address. */ + PJ_DNS_TYPE_SIG = 24, /**< Signature. */ + PJ_DNS_TYPE_KEY = 25, /**< Key. */ + PJ_DNS_TYPE_PX = 26, /**< X.400 mail mapping. */ + PJ_DNS_TYPE_GPOS = 27, /**< Geographical position (withdrawn) */ + PJ_DNS_TYPE_AAAA = 28, /**< IPv6 address. */ + PJ_DNS_TYPE_LOC = 29, /**< Location. */ + PJ_DNS_TYPE_NXT = 30, /**< Next valid name in the zone. */ + PJ_DNS_TYPE_EID = 31, /**< Endpoint idenfitier. */ + PJ_DNS_TYPE_NIMLOC = 32, /**< Nimrod locator. */ + PJ_DNS_TYPE_SRV = 33, /**< Server selection (SRV) record. */ + PJ_DNS_TYPE_ATMA = 34, /**< DNS ATM address record. */ + PJ_DNS_TYPE_NAPTR = 35, /**< DNS Naming authority pointer record. */ + PJ_DNS_TYPE_KX = 36, /**< DNS key exchange record. */ + PJ_DNS_TYPE_CERT = 37, /**< DNS certificate record. */ + PJ_DNS_TYPE_A6 = 38, /**< DNS IPv6 address (experimental) */ + PJ_DNS_TYPE_DNAME = 39, /**< DNS non-terminal name redirection rec. */ + + PJ_DNS_TYPE_OPT = 41, /**< DNS options - contains EDNS metadata. */ + PJ_DNS_TYPE_APL = 42, /**< DNS Address Prefix List (APL) record. */ + PJ_DNS_TYPE_DS = 43, /**< DNS Delegation Signer (DS) */ + PJ_DNS_TYPE_SSHFP = 44, /**< DNS SSH Key Fingerprint */ + PJ_DNS_TYPE_IPSECKEY= 45, /**< DNS IPSEC Key. */ + PJ_DNS_TYPE_RRSIG = 46, /**< DNS Resource Record signature. */ + PJ_DNS_TYPE_NSEC = 47, /**< DNS Next Secure Name. */ + PJ_DNS_TYPE_DNSKEY = 48 /**< DNSSEC Key. */ +} pj_dns_type; + + + +/** + * Standard DNS header, according to RFC 1035, which will be present in + * both DNS query and DNS response. + * + * Note that all values seen by application would be in + * host by order. The library would convert them to network + * byte order as necessary. + */ +typedef struct pj_dns_hdr +{ + pj_uint16_t id; /**< Transaction ID. */ + pj_uint16_t flags; /**< Flags. */ + pj_uint16_t qdcount; /**< Nb. of queries. */ + pj_uint16_t anscount; /**< Nb. of res records */ + pj_uint16_t nscount; /**< Nb. of NS records. */ + pj_uint16_t arcount; /**< Nb. of additional records */ +} pj_dns_hdr; + +/** Create RCODE flag */ +#define PJ_DNS_SET_RCODE(c) ((pj_uint16_t)((c) & 0x0F)) + +/** Create RA (Recursion Available) bit */ +#define PJ_DNS_SET_RA(on) ((pj_uint16_t)((on) << 7)) + +/** Create RD (Recursion Desired) bit */ +#define PJ_DNS_SET_RD(on) ((pj_uint16_t)((on) << 8)) + +/** Create TC (Truncated) bit */ +#define PJ_DNS_SET_TC(on) ((pj_uint16_t)((on) << 9)) + +/** Create AA (Authoritative Answer) bit */ +#define PJ_DNS_SET_AA(on) ((pj_uint16_t)((on) << 10)) + +/** Create four bits opcode */ +#define PJ_DNS_SET_OPCODE(o) ((pj_uint16_t)((o) << 11)) + +/** Create query/response bit */ +#define PJ_DNS_SET_QR(on) ((pj_uint16_t)((on) << 15)) + + +/** Get RCODE value */ +#define PJ_DNS_GET_RCODE(val) (((val) & PJ_DNS_SET_RCODE(0x0F)) >> 0) + +/** Get RA bit */ +#define PJ_DNS_GET_RA(val) (((val) & PJ_DNS_SET_RA(1)) >> 7) + +/** Get RD bit */ +#define PJ_DNS_GET_RD(val) (((val) & PJ_DNS_SET_RD(1)) >> 8) + +/** Get TC bit */ +#define PJ_DNS_GET_TC(val) (((val) & PJ_DNS_SET_TC(1)) >> 9) + +/** Get AA bit */ +#define PJ_DNS_GET_AA(val) (((val) & PJ_DNS_SET_AA(1)) >> 10) + +/** Get OPCODE value */ +#define PJ_DNS_GET_OPCODE(val) (((val) & PJ_DNS_SET_OPCODE(0x0F)) >> 11) + +/** Get QR bit */ +#define PJ_DNS_GET_QR(val) (((val) & PJ_DNS_SET_QR(1)) >> 15) + + +/** + * These constants describe DNS RCODEs. Application can fold these constants + * into PJLIB pj_status_t namespace by calling #PJ_STATUS_FROM_DNS_RCODE() + * macro. + */ +typedef enum pj_dns_rcode +{ + PJ_DNS_RCODE_FORMERR = 1, /**< Format error. */ + PJ_DNS_RCODE_SERVFAIL = 2, /**< Server failure. */ + PJ_DNS_RCODE_NXDOMAIN = 3, /**< Name Error. */ + PJ_DNS_RCODE_NOTIMPL = 4, /**< Not Implemented. */ + PJ_DNS_RCODE_REFUSED = 5, /**< Refused. */ + PJ_DNS_RCODE_YXDOMAIN = 6, /**< The name exists. */ + PJ_DNS_RCODE_YXRRSET = 7, /**< The RRset (name, type) exists. */ + PJ_DNS_RCODE_NXRRSET = 8, /**< The RRset (name, type) doesn't exist*/ + PJ_DNS_RCODE_NOTAUTH = 9, /**< Not authorized. */ + PJ_DNS_RCODE_NOTZONE = 10 /**< The zone specified is not a zone. */ + +} pj_dns_rcode; + + +/** + * This structure describes a DNS query record. + */ +typedef struct pj_dns_parsed_query +{ + pj_str_t name; /**< The domain in the query. */ + pj_uint16_t type; /**< Type of the query (pj_dns_type) */ + pj_uint16_t dnsclass; /**< Network class (PJ_DNS_CLASS_IN=1) */ +} pj_dns_parsed_query; + + +/** + * This structure describes a Resource Record parsed from the DNS packet. + * All integral values are in host byte order. + */ +typedef struct pj_dns_parsed_rr +{ + pj_str_t name; /**< The domain name which this rec pertains. */ + pj_uint16_t type; /**< RR type code. */ + pj_uint16_t dnsclass; /**< Class of data (PJ_DNS_CLASS_IN=1). */ + pj_uint32_t ttl; /**< Time to live. */ + pj_uint16_t rdlength; /**< Resource data length. */ + void *data; /**< Pointer to the raw resource data, only + when the type is not known. If it is known, + the data will be put in rdata below. */ + + /** For resource types that are recognized/supported by this library, + * the parsed resource data will be placed in this rdata union. + */ + union rdata + { + /** SRV Resource Data (PJ_DNS_TYPE_SRV, 33) */ + struct srv { + pj_uint16_t prio; /**< Target priority (lower is higher). */ + pj_uint16_t weight; /**< Weight/proportion */ + pj_uint16_t port; /**< Port number of the service */ + pj_str_t target; /**< Target name. */ + } srv; + + /** CNAME Resource Data (PJ_DNS_TYPE_CNAME, 5) */ + struct cname { + pj_str_t name; /**< Primary canonical name for an alias. */ + } cname; + + /** NS Resource Data (PJ_DNS_TYPE_NS, 2) */ + struct ns { + pj_str_t name; /**< Primary name server. */ + } ns; + + /** PTR Resource Data (PJ_DNS_TYPE_PTR, 12) */ + struct ptr { + pj_str_t name; /**< PTR name. */ + } ptr; + + /** A Resource Data (PJ_DNS_TYPE_A, 1) */ + struct a { + pj_in_addr ip_addr;/**< IPv4 address in network byte order. */ + } a; + + /** AAAA Resource Data (PJ_DNS_TYPE_AAAA, 28) */ + struct aaaa { + pj_in6_addr ip_addr;/**< IPv6 address in network byte order. */ + } aaaa; + + } rdata; + +} pj_dns_parsed_rr; + + +/** + * This structure describes the parsed repersentation of the raw DNS packet. + * Note that all integral values in the parsed packet are represented in + * host byte order. + */ +typedef struct pj_dns_parsed_packet +{ + pj_dns_hdr hdr; /**< Pointer to DNS hdr, in host byte order */ + pj_dns_parsed_query *q; /**< Array of DNS queries. */ + pj_dns_parsed_rr *ans; /**< Array of DNS RR answer. */ + pj_dns_parsed_rr *ns; /**< Array of NS record in the answer. */ + pj_dns_parsed_rr *arr; /**< Array of additional RR answer. */ +} pj_dns_parsed_packet; + + +/** + * Option flags to be specified when calling #pj_dns_packet_dup() function. + * These flags can be combined with bitwise OR operation. + */ +enum pj_dns_dup_options +{ + PJ_DNS_NO_QD = 1, /**< Do not duplicate the query section. */ + PJ_DNS_NO_ANS = 2, /**< Do not duplicate the answer section. */ + PJ_DNS_NO_NS = 4, /**< Do not duplicate the NS section. */ + PJ_DNS_NO_AR = 8 /**< Do not duplicate the additional rec section */ +}; + + +/** + * Create DNS query packet to resolve the specified names. This function + * can be used to build any types of DNS query, such as A record or DNS SRV + * record. + * + * Application specifies the type of record and the name to be queried, + * and the function will build the DNS query packet into the buffer + * specified. Once the packet is successfully built, application can send + * the packet via TCP or UDP connection. + * + * @param packet The buffer to put the DNS query packet. + * @param size On input, it specifies the size of the buffer. + * On output, it will be filled with the actual size of + * the DNS query packet. + * @param id DNS query ID to associate DNS response with the + * query. + * @param qtype DNS type of record to be queried (see #pj_dns_type). + * @param name Name to be queried from the DNS server. + * + * @return PJ_SUCCESS on success, or the appropriate error code. + */ +PJ_DECL(pj_status_t) pj_dns_make_query(void *packet, + unsigned *size, + pj_uint16_t id, + int qtype, + const pj_str_t *name); + +/** + * Parse raw DNS packet into parsed DNS packet structure. This function is + * able to parse few DNS resource records such as A record, PTR record, + * CNAME record, NS record, and SRV record. + * + * @param pool Pool to allocate memory for the parsed packet. + * @param packet Pointer to the DNS packet (the TCP/UDP payload of + * the raw packet). + * @param size The size of the DNS packet. + * @param p_res Pointer to store the resulting parsed packet. + * + * @return PJ_SUCCESS on success, or the appropriate error code. + */ +PJ_DECL(pj_status_t) pj_dns_parse_packet(pj_pool_t *pool, + const void *packet, + unsigned size, + pj_dns_parsed_packet **p_res); + +/** + * Duplicate DNS packet. + * + * @param pool The pool to allocate memory for the duplicated packet. + * @param p The DNS packet to be cloned. + * @param options Option flags, from pj_dns_dup_options. + * @param p_dst Pointer to store the cloned DNS packet. + */ +PJ_DECL(void) pj_dns_packet_dup(pj_pool_t *pool, + const pj_dns_parsed_packet*p, + unsigned options, + pj_dns_parsed_packet **p_dst); + + +/** + * Utility function to get the type name string of the specified DNS type. + * + * @param type DNS type (see #pj_dns_type). + * + * @return String name of the type (e.g. "A", "SRV", etc.). + */ +PJ_DECL(const char *) pj_dns_get_type_name(int type); + + +/** + * Initialize DNS record as DNS SRV record. + * + * @param rec The DNS resource record to be initialized as DNS + * SRV record. + * @param res_name Resource name. + * @param dnsclass DNS class. + * @param ttl Resource TTL value. + * @param prio DNS SRV priority. + * @param weight DNS SRV weight. + * @param port Target port. + * @param target Target name. + */ +PJ_DECL(void) pj_dns_init_srv_rr(pj_dns_parsed_rr *rec, + const pj_str_t *res_name, + unsigned dnsclass, + unsigned ttl, + unsigned prio, + unsigned weight, + unsigned port, + const pj_str_t *target); + +/** + * Initialize DNS record as DNS CNAME record. + * + * @param rec The DNS resource record to be initialized as DNS + * CNAME record. + * @param res_name Resource name. + * @param dnsclass DNS class. + * @param ttl Resource TTL value. + * @param name Host name. + */ +PJ_DECL(void) pj_dns_init_cname_rr(pj_dns_parsed_rr *rec, + const pj_str_t *res_name, + unsigned dnsclass, + unsigned ttl, + const pj_str_t *name); + +/** + * Initialize DNS record as DNS A record. + * + * @param rec The DNS resource record to be initialized as DNS + * A record. + * @param res_name Resource name. + * @param dnsclass DNS class. + * @param ttl Resource TTL value. + * @param ip_addr Host address. + */ +PJ_DECL(void) pj_dns_init_a_rr(pj_dns_parsed_rr *rec, + const pj_str_t *res_name, + unsigned dnsclass, + unsigned ttl, + const pj_in_addr *ip_addr); + +/** + * Dump DNS packet to standard log. + * + * @param res The DNS packet. + */ +PJ_DECL(void) pj_dns_dump_packet(const pj_dns_parsed_packet *res); + + +/** + * @} + */ + +PJ_END_DECL + + +#endif /* __PJLIB_UTIL_DNS_H__ */ + |