zeroconf/mdns.h

243 lines
7.2 KiB
C

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