244 lines
7.3 KiB
C
244 lines
7.3 KiB
C
/*
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* tinysvcmdns - a tiny MDNS implementation for publishing services
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* Copyright (C) 2011 Darell Tan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __MDNS_H__
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#define __MDNS_H__
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#ifdef _WIN32
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#include <winsock.h>
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#else
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#include <arpa/inet.h>
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#endif
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/* see RFC 6762 Section 10 */
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#define DEFAULT_TTL_FOR_RECORD_WITH_HOSTNAME 120
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#define DEFAULT_TTL 4500
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/* see RFC 6762 Section 5.4 */
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#define DEFAULT_TTL_LEGACY 10
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#ifndef MDNS_DEBUG_PRINTF
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#define MDNS_DEBUG_PRINTF 0
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#endif
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#if MDNS_DEBUG_PRINTF==1
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#define MDNS_RR_DEBUG 0
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#define MDNS_MEMORY_DEBUG 0
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#endif
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#if MDNS_DEBUG_PRINTF==1 && MDNS_MEMORY_DEBUG==1
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void *mdns_malloc(const char *func_name, int line, unsigned int size);
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void mdns_free(const char *func_name, int line, void *ptr);
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char *mdns_strdup(const char *func_name, int line, const char *str);
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void mdns_show_meminfo(void);
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#define MDNS_MALLOC(size) mdns_malloc(__FUNCTION__, __LINE__, size)
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#define MDNS_FREE(ptr) mdns_free(__FUNCTION__, __LINE__, ptr)
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#define MDNS_STRDUP(str) mdns_strdup(__FUNCTION__, __LINE__, str)
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#else
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#define MDNS_MALLOC(size) malloc(size)
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#define MDNS_FREE(ptr) free(ptr)
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#define MDNS_STRDUP(size) strdup(size)
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#endif
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#define MALLOC_ZERO_STRUCT(x, type) \
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x = MDNS_MALLOC(sizeof(struct type)); \
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memset(x, 0, sizeof(struct type))
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#define DECL_MALLOC_ZERO_STRUCT(x, type) \
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struct type * MALLOC_ZERO_STRUCT(x, type)
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#define DECL_ZERO_STRUCT(_x, _type) \
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struct _type _x; \
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memset(&(_x), 0, sizeof(struct _type))
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#if MDNS_DEBUG_PRINTF==1
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#define DEBUG_PRINTF(...) printf(__VA_ARGS__)
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#else
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#define DEBUG_PRINTF(...) ((void) 0)
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#endif
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#define MDNS_RR_DEBUG_PRINTF(...) printf(__VA_ARGS__)
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struct rr_data_srv {
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uint16_t priority;
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uint16_t weight;
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uint16_t port;
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uint8_t *target; // host
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};
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struct rr_data_txt {
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struct rr_data_txt *next;
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uint8_t *txt;
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};
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struct rr_data_nsec {
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//uint8_t *name; // same as record
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// NSEC occupies the 47th bit, 5 bytes
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//uint8_t bitmap_len; // = 5
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uint8_t bitmap[5]; // network order: first byte contains LSB
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};
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struct rr_data_ptr {
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uint8_t *name; // NULL if entry is to be used
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struct rr_entry *entry;
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};
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struct rr_data_a {
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uint32_t addr;
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};
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struct rr_data_aaaa {
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struct in6_addr *addr;
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};
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struct rr_entry {
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uint8_t *name;
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enum rr_type {
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RR_A = 0x01,
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RR_PTR = 0x0C,
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RR_TXT = 0x10,
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RR_AAAA = 0x1C,
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RR_SRV = 0x21,
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RR_NSEC = 0x2F,
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RR_ANY = 0xFF,
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} type;
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uint32_t ttl;
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// for use in Questions only
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char unicast_query;
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// for use in Answers only
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char cache_flush;
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uint16_t rr_class;
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// RR data
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union {
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struct rr_data_nsec NSEC;
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struct rr_data_srv SRV;
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struct rr_data_txt TXT;
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struct rr_data_ptr PTR;
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struct rr_data_a A;
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struct rr_data_aaaa AAAA;
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} data;
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time_t update_time;
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};
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struct rr_list {
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struct rr_entry *e;
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struct rr_list *next;
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};
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struct rr_group {
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uint8_t *name;
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struct rr_list *rr;
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struct rr_group *next;
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};
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#define MDNS_FLAG_RESP (1 << 15) // Query=0 / Response=1
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#define MDNS_FLAG_AA (1 << 10) // Authoritative
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#define MDNS_FLAG_TC (1 << 9) // TrunCation
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#define MDNS_FLAG_RD (1 << 8) // Recursion Desired
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#define MDNS_FLAG_RA (1 << 7) // Recursion Available
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#define MDNS_FLAG_Z (1 << 6) // Reserved (zero)
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#define MDNS_FLAG_GET_RCODE(x) (x & 0x0F)
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#define MDNS_FLAG_GET_OPCODE(x) ((x >> 11) & 0x0F)
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// gets the PTR target name, either from "name" member or "entry" member
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#define MDNS_RR_GET_PTR_NAME(rr) (rr->data.PTR.name != NULL ? rr->data.PTR.name : rr->data.PTR.entry->name)
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struct mdns_pkt {
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uint16_t id; // transaction ID
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uint16_t flags;
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uint16_t num_qn;
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uint16_t num_ans_rr;
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uint16_t num_auth_rr;
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uint16_t num_add_rr;
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struct rr_list *rr_qn; // questions
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struct rr_list *rr_ans; // answer RRs
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struct rr_list *rr_auth; // authority RRs
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struct rr_list *rr_add; // additional RRs
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};
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struct mdns_pkt *mdns_parse_pkt(uint8_t *pkt_buf, size_t pkt_len);
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void mdns_init_query(struct mdns_pkt *pkt, uint16_t id);
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void mdns_init_reply(struct mdns_pkt *pkt, uint16_t id);
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size_t mdns_encode_pkt(struct mdns_pkt *encoded_pkt, uint8_t *pkt_buf, size_t pkt_len);
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void mdns_pkt_destroy(struct mdns_pkt *p);
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void rr_group_destroy(struct rr_group *group);
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struct rr_group *rr_group_find(struct rr_group *g, uint8_t *name);
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struct rr_entry *rr_entry_find(struct rr_list *rr_list, uint8_t *name, uint16_t type);
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struct rr_entry *rr_entry_match(struct rr_list *rr_list, struct rr_entry *entry);
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void rr_group_add(struct rr_group **group, struct rr_entry *rr);
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void rr_group_del(struct rr_group **group, struct rr_entry *rr);
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int rr_list_count(struct rr_list *rr);
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int rr_list_append(struct rr_list **rr_head, struct rr_entry *rr);
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struct rr_entry *rr_list_remove(struct rr_list **rr_head, struct rr_entry *rr);
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void rr_list_destroy(struct rr_list *rr, char destroy_items);
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struct rr_entry *qn_create(uint8_t *name, enum rr_type type, int unicast_query);
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struct rr_entry *rr_create_ptr(uint8_t *name, struct rr_entry *d_rr);
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struct rr_entry *rr_create_srv(uint8_t *name, uint16_t port, uint8_t *target);
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struct rr_entry *rr_create_aaaa(uint8_t *name, struct in6_addr *addr);
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struct rr_entry *rr_create_a(uint8_t *name, uint32_t addr);
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struct rr_entry *rr_create(uint8_t *name, enum rr_type type);
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struct rr_entry *rr_duplicate(struct rr_entry *rr_src);
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void rr_set_nsec(struct rr_entry *rr_nsec, enum rr_type type);
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void rr_add_txt(struct rr_entry *rr_txt, const char *txt);
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const char *rr_get_type_name(enum rr_type type);
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uint8_t *create_label(const char *txt);
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uint8_t *create_nlabel(const char *name);
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char *nlabel_to_str(const uint8_t *name);
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uint8_t *dup_label(const uint8_t *label);
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uint8_t *dup_nlabel(const uint8_t *n);
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uint8_t *join_nlabel(const uint8_t *n1, const uint8_t *n2);
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// compares 2 names
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static inline int cmp_nlabel(const uint8_t *L1, const uint8_t *L2) {
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return strcmp((char *) L1, (char *) L2);
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}
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#endif /*!__MDNS_H__*/
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