dns.h

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#pragma once
/*
 *  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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: ccd4976e6e62129e2296fc9db32c33ed27714112 $
 *
 * @file protocols/dns/dns.h
 * @brief Implementation of the DNS protocol.
 *
 * @copyright 2021 Network RADIUS SAS (legal@networkradius.com)
 */
RCSIDH(dhcp_h, "$Id: ccd4976e6e62129e2296fc9db32c33ed27714112 $")
 
#ifdef __cplusplus
extern "C" {
#endif
 
#include <freeradius-devel/util/packet.h>
#include <freeradius-devel/util/dns.h>
 
#define DNS_MAX_ATTRIBUTES      255
 
typedef struct {
        uint16_t        id;
#ifdef WORDS_BIGENDIAN
        unsigned int    query                   : 1;
        unsigned int    opcode                  : 4;
        unsigned int    authoritative           : 1;
        unsigned int    truncated               : 1;
        unsigned int    recursion_desired       : 1;
#else
        unsigned int    recursion_desired       : 1;
        unsigned int    truncated               : 1;
        unsigned int    authoritative           : 1;
        unsigned int    opcode                  : 4;
        unsigned int    query                   : 1;
#endif
 
#ifdef WORDS_BIGENDIAN
        unsigned int    recursion_available     : 1;
        unsigned int    reserved                : 1;
        unsigned int    authentic_data          : 1;
        unsigned int    checking_disabled       : 1;
        unsigned int    rcode                   : 4;
#else
        unsigned int    rcode                   : 4;
        unsigned int    checking_disabled       : 1;
        unsigned int    authentic_data          : 1;
        unsigned int    reserved                : 1;
        unsigned int    recursion_available     : 1;
#endif
 
        uint16_t        qdcount;
        uint16_t        ancount;
        uint16_t        nscount;
        uint16_t        arcount;
} CC_HINT(__packed__) fr_dns_packet_t;
 
typedef struct {
        TALLOC_CTX              *tmp_ctx;               //!< for temporary things cleaned up during decoding
        uint8_t const           *packet;                //!< DNS labels can point anywhere in the packet :(
        size_t                  packet_len;
        fr_dns_labels_t         *lb;
} fr_dns_ctx_t;
 
int             fr_dns_global_init(void);
void            fr_dns_global_free(void);
 
typedef enum {
        FR_DNS_QUERY = 0,
        FR_DNS_INVERSE_QUERY = 1,
        FR_DNS_STATUS = 2,
        FR_DNS_NOTIFY = 4,
        FR_DNS_UPDATE = 5,
        FR_DNS_STATEFUL_OPERATION = 6,
        FR_DNS_CODE_MAX = 7,
 
        FR_DNS_QUERY_RESPONSE = 16,
        FR_DNS_INVERSE_QUERY_RESPONSE = 17,
        FR_DNS_STATUS_RESPONSE = 18,
        FR_DNS_NOTIFY_RESPONSE = 20,
        FR_DNS_UPDATE_RESPONSE = 21,
        FR_DNS_STATEFUL_OPERATION_RESPONSE = 22,
 
        FR_DNS_DO_NOT_RESPOND = 256,
} fr_dns_packet_code_t;
 
typedef enum {
        FR_DNS_DECODE_FAIL_NONE = 0,
        FR_DNS_DECODE_FAIL_MIN_LENGTH_PACKET,
        FR_DNS_DECODE_FAIL_MAX_LENGTH_PACKET,
        FR_DNS_DECODE_FAIL_UNEXPECTED,
        FR_DNS_DECODE_FAIL_NO_QUESTIONS,
        FR_DNS_DECODE_FAIL_ANSWERS_IN_QUESTION,
        FR_DNS_DECODE_FAIL_NS_IN_QUESTION,
        FR_DNS_DECODE_FAIL_INVALID_RR_LABEL,
        FR_DNS_DECODE_FAIL_MISSING_RR_HEADER,
        FR_DNS_DECODE_FAIL_MISSING_RR_LEN,
        FR_DNS_DECODE_FAIL_ZERO_RR_LEN,
        FR_DNS_DECODE_FAIL_RR_OVERFLOWS_PACKET,
        FR_DNS_DECODE_FAIL_TOO_MANY_RRS,
        FR_DNS_DECODE_FAIL_TOO_FEW_RRS,
        FR_DNS_DECODE_FAIL_POINTER_TO_NON_LABEL,
        FR_DNS_DECODE_FAIL_POINTER_OVERFLOWS_PACKET,
        FR_DNS_DECODE_FAIL_POINTER_TO_HEADER,
        FR_DNS_DECODE_FAIL_POINTER_LOOPS,
        FR_DNS_DECODE_FAIL_INVALID_POINTER,
        FR_DNS_DECODE_FAIL_LABEL_OVERFLOWS_PACKET,
        FR_DNS_DECODE_FAIL_LABEL_TOO_LONG,
        FR_DNS_DECODE_FAIL_MISSING_QD_HEADER,
        FR_DNS_DECODE_FAIL_MISSING_TLV_HEADER,
        FR_DNS_DECODE_FAIL_TLV_OVERFLOWS_RR,
        FR_DNS_DECODE_FAIL_MAX
} fr_dns_decode_fail_t;
 
#define FR_DNS_PACKET_CODE_VALID(_code) (((_code) < FR_DNS_CODE_MAX) || (((_code & 0x10) != 0) && ((_code & ~0x10) < FR_DNS_CODE_MAX)))
 
#define DNS_HDR_LEN (12)
 
typedef struct {
        bool                    dns_label;
        bool                    dns_label_uncompressed;
} fr_dns_attr_flags_t;
 
static inline fr_dns_attr_flags_t const *fr_dns_attr_flags(fr_dict_attr_t const *da)
{
        return fr_dict_attr_ext(da, FR_DICT_ATTR_EXT_PROTOCOL_SPECIFIC);
}
 
static inline bool fr_dns_flag_dns_label_any(fr_dict_attr_t const *da)
{
        fr_dns_attr_flags_t const *flags = fr_dns_attr_flags(da);
 
        return flags->dns_label || flags->dns_label_uncompressed;
}
 
#define fr_dns_flag_dns_label(_da)                      (fr_dns_attr_flags(_da)->dns_label)
#define fr_dns_flag_dns_label_uncompressed(_da)         (fr_dns_attr_flags(_da)->dns_label_uncompressed)
 
extern fr_table_num_ordered_t fr_dns_reason_fail_table[];
extern char const *fr_dns_packet_names[FR_DNS_CODE_MAX];
extern size_t fr_dns_reason_fail_table_len;
 
bool fr_dns_packet_ok(uint8_t const *packet, size_t packet_len, bool query, fr_dns_decode_fail_t *reason);
 
fr_dns_labels_t *fr_dns_labels_get(uint8_t const *packet, size_t packet_len, bool init_mark);
 
ssize_t fr_dns_decode(TALLOC_CTX *ctx, fr_pair_list_t *out,
                      uint8_t const *packet, size_t packet_len, fr_dns_ctx_t *packet_ctx);
 
ssize_t fr_dns_encode(fr_dbuff_t *dbuff, fr_pair_list_t *vps, fr_dns_ctx_t *encode_ctx);
 
#ifdef __cplusplus
}
#endif