1035.h

Go to the documentation of this file.

/** Familiarize yourself with RFC1035 if you want to know what all the
 * variable names mean.  This file hides most of the dirty work all of
 * this code depends on the buffer space a packet is in being 4096 and
 * zero'd before the packet is copied in also conveniently decodes srv
 * rr's, type 33, see RFC2782
 */
#ifndef MDNS_1035_H_
#define MDNS_1035_H_
 
#ifdef __cplusplus
extern "C" {
#endif
 
#include "mdnsd_config.h"
 
#ifdef _WIN32
 
/** Backup definition of SLIST_ENTRY on mingw winnt.h */
#ifdef SLIST_ENTRY
# pragma push_macro("SLIST_ENTRY")
# undef SLIST_ENTRY
# define POP_SLIST_ENTRY
#endif
 
/** winnt.h redefines SLIST_ENTRY */
# define _WINSOCK_DEPRECATED_NO_WARNINGS /* inet_ntoa is deprecated on MSVC but used for compatibility */
# include <winsock2.h>
# include <ws2tcpip.h>
 
#ifndef in_addr_t
#define in_addr_t unsigned __int32
#endif
 
/** restore definition */
#ifdef POP_SLIST_ENTRY
# undef SLIST_ENTRY
# undef POP_SLIST_ENTRY
# pragma pop_macro("SLIST_ENTRY")
#endif
 
 
#else
# include <arpa/inet.h>
#endif
 
#if !defined(__bool_true_false_are_defined) && defined(_MSC_VER) && _MSC_VER < 1600
// VS 2008 has no stdbool.h
#define bool    short
#define true    1
#define false   0
#else
#include <stdbool.h>
#endif
 
#ifdef _MSC_VER
#include "ms_stdint.h" /* Includes stdint.h or workaround for older Visual Studios */
#else
#include <stdint.h>
#endif
 
/** Should be reasonably large, for UDP */
#define MAX_PACKET_LEN 10000
#define MAX_NUM_LABELS 20
 
struct question {
    char *name;
    unsigned short type, clazz;
};
 
#define QTYPE_A      1
#define QTYPE_NS     2
#define QTYPE_CNAME  5
#define QTYPE_PTR    12
#define QTYPE_TXT    16
#define QTYPE_SRV    33
 
struct resource {
    char *name;
    unsigned short type, clazz;
    unsigned long int ttl;
    unsigned short int rdlength;
    unsigned char *rdata;
    union {
        struct {
            struct in_addr ip;
            //cppcheck-suppress unusedStructMember
            char *name;
        } a;
        struct {
            //cppcheck-suppress unusedStructMember
            char *name;
        } ns;
        struct {
            //cppcheck-suppress unusedStructMember
            char *name;
        } cname;
        struct {
            //cppcheck-suppress unusedStructMember
            char *name;
        } ptr;
        struct {
            //cppcheck-suppress unusedStructMember
            unsigned short int priority, weight, port;
            //cppcheck-suppress unusedStructMember
            char *name;
        } srv;
    } known;
};
 
struct message {
    /* External data */
    unsigned short int id;
    struct {
        //it would be better to use unsigned short, but gcc < 5 complaints when using pedantic
        //cppcheck-suppress unusedStructMember
        unsigned int qr:1, opcode:4, aa:1, tc:1, rd:1, ra:1, z:3, rcode:4;
    } header;
    unsigned short int qdcount, ancount, nscount, arcount;
    struct question *qd;
    struct resource *an, *ns, *ar;
 
    /* Internal variables */
    unsigned char *_buf;
    unsigned char *_bufEnd;
    char *_labels[MAX_NUM_LABELS];
    size_t _len;
    int _label;
 
    /* Packet acts as padding, easier mem management */
    unsigned char _packet[MAX_PACKET_LEN];
};
 
 
uint16_t net2short(const unsigned char **bufp);
uint32_t  net2long (const unsigned char **bufp);
 
 
void MDNSD_EXPORT short2net(uint16_t i, unsigned char **bufp);
void MDNSD_EXPORT long2net (uint32_t  l, unsigned char **bufp);
 
 
bool MDNSD_EXPORT message_parse(struct message *m, unsigned char *packet, size_t packetLen);
 
 
struct message *message_wire(void);
 
 
void MDNSD_EXPORT message_qd(struct message *m, char *name, unsigned short int type, unsigned short int clazz);
 
 
void MDNSD_EXPORT message_an(struct message *m, char *name, unsigned short int type, unsigned short int clazz, unsigned long ttl);
void MDNSD_EXPORT message_ns(struct message *m, char *name, unsigned short int type, unsigned short int clazz, unsigned long ttl);
void MDNSD_EXPORT message_ar(struct message *m, char *name, unsigned short int type, unsigned short int clazz, unsigned long ttl);
 
 
void MDNSD_EXPORT message_rdata_long (struct message *m, struct in_addr l);
void MDNSD_EXPORT message_rdata_name (struct message *m, char *name);
void MDNSD_EXPORT message_rdata_srv  (struct message *m, unsigned short int priority, unsigned short int weight,
             unsigned short int port, char *name);
void MDNSD_EXPORT message_rdata_raw  (struct message *m, unsigned char *rdata, unsigned short int rdlength);
 
 
unsigned char MDNSD_EXPORT * message_packet     (struct message *m);
int   MDNSD_EXPORT           message_packet_len (struct message *m);
 
#ifdef __cplusplus
} // extern "C"
#endif
 
#endif  /* MDNS_1035_H_ */