mDNSMacOSX/mdns_objects/log_mdns.m

   1 /*
   2  * Copyright (c) 2019-2020 Apple Inc. All rights reserved.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     https://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #import "DNSMessage.h"
  18
  19 #import <CoreUtils/CoreUtils.h>
  20 #import <Foundation/Foundation.h>
  21 #import <os/log_private.h>
  22
  23 #if !COMPILER_ARC
  24         #error "This file must be compiled with ARC."
  25 #endif
  26
  27 //======================================================================================================================
  28 // MARK: - Specifiers
  29 //
  30 //      Data Type                               Specifier                                                       Arguments                                                       Notes
  31 //      DNS message                             %{mdns:dnsmsg}.*P                                       length (int), pointer (void *)          -
  32 //      DNS message header              %{mdns:dnshdr}.*P                                       length (int), pointer (void *)          -
  33 //      Error code integer              %{mdns:err}d, %{mdns:err}ld, etc.       error code (int, OSStatus, etc.)        1
  34 //      DNS record data                 %{mdns:rd.<record type>}.*P                     length (int), pointer (void *)          2,3,4
  35 //      DNS record type                 %{mdns:rrtype}d                                         record type (int)
  36 //
  37 //      Notes:
  38 //      1. Formatting is handled by NSPrintTypedObject() from the CoreUtils framework, which handles a large variety of
  39 //         error codes, including errno and kDNSServiceErr_* error codes.
  40 //      2. The DNS record data must be fully expanded, i.e., it must not contain any compressed DNS domain names.
  41 //      3. The <record type> portion of the specifier is a case-insensitive DNS record type mnemonic, e.g., A, AAAA,
  42 //         DNSKEY, DS, etc.
  43 //      4. Formatting is handled by DNSRecordDataToString(), which currently only handles a subset of record types.
  44 //         This subset consists of the record types most commonly encountered by mDNSResponder. This subset may grow
  45 //         as needed.
  46 //
  47 //      The specifiers for DNSSEC record data, %{mdns:dnskey}, %{mdns:ds}, %{mdns:nsec}, %{mdns:nsec3}, and
  48 //      %{mdns:rrsig}, have been deprecated in favor of the %{mdns:rd.<record type>} style of record data specifiers.
  49
  50 #define LOG_MDNS_SPECIFIER_DNS_MESSAGE                  "dnsmsg"
  51 #define LOG_MDNS_SPECIFIER_DNS_MESSAGE_HEADER   "dnshdr"
  52 #define LOG_MDNS_SPECIFIER_ERROR                                "err"
  53 #define LOG_MDNS_SPECIFIER_RDATA_PREFIX                 "rd."
  54 #define LOG_MDNS_SPECIFIER_DNS_RECORD_TYPE              "rrtype"
  55
  56 //======================================================================================================================
  57 // MARK: - Data Structures
  58
  59 typedef NSAttributedString *
  60 (*log_mdns_data_formatter_f)(NSData *data);
  61
  62 typedef struct {
  63         const char *                            specifier;
  64         log_mdns_data_formatter_f       formatter;
  65 } log_mdns_data_formatter_item_t;
  66
  67 typedef NSAttributedString *
  68 (*log_mdns_number_formatter_f)(NSNumber *number);
  69
  70 typedef struct {
  71         const char *                            specifier;
  72         log_mdns_number_formatter_f     formatter;
  73 } log_mdns_number_formatter_item_t;
  74
  75 //======================================================================================================================
  76 // MARK: - Local Prototypes
  77
  78 static NSAttributedString *
  79 _log_mdns_format_dns_message(NSData *data);
  80
  81 static NSAttributedString *
  82 _log_mdns_format_dns_message_header(NSData *data);
  83
  84 static NSAttributedString *
  85 _log_mdns_format_record_data(NSData *data, int record_type);
  86
  87 static NSAttributedString *
  88 _log_mdns_format_err(NSNumber *number);
  89
  90 static NSAttributedString *
  91 _log_mdns_format_dns_record_type(NSNumber *number);
  92
  93 static NSAttributedString *
  94 _log_mdns_format_dns_message_ex(NSData *data, DNSMessageToStringFlags extra_flags);
  95
  96 //======================================================================================================================
  97 // MARK: - DNS Record Data Formatters
  98
  99 #define LOG_MDNS_DEFINE_RDATA_FORMATTER(RECORD_TYPE)                                                            \
 100         static NSAttributedString *                                                                                                             \
 101         _log_mdns_format_record_data_ ## RECORD_TYPE (NSData * const rdata)                             \
 102         {                                                                                                                                                               \
 103                 return _log_mdns_format_record_data(rdata, kDNSRecordType_ ## RECORD_TYPE);     \
 104         }                                                                                                                                                               \
 105         extern int _log_mdns_dummy_variable
 106
 107 LOG_MDNS_DEFINE_RDATA_FORMATTER(DNSKEY);
 108 LOG_MDNS_DEFINE_RDATA_FORMATTER(DS);
 109 LOG_MDNS_DEFINE_RDATA_FORMATTER(NSEC);
 110 LOG_MDNS_DEFINE_RDATA_FORMATTER(NSEC3);
 111 LOG_MDNS_DEFINE_RDATA_FORMATTER(RRSIG);
 112
 113 //======================================================================================================================
 114 // MARK: - External Functions
 115
 116 #define LOG_MDNS_RDATA_FORMATTER_ITEM(RECORD_TYPE)      { # RECORD_TYPE, _log_mdns_format_record_data_ ## RECORD_TYPE }
 117
 118 NSAttributedString *
 119 OSLogCopyFormattedString(const char * const specifier, const id arg, __unused const os_log_type_info_t info)
 120 {
 121         if ([arg isKindOfClass:[NSData class]]) {
 122                 NSData * const data = (NSData *)arg;
 123                 if (stricmp_prefix(specifier, LOG_MDNS_SPECIFIER_RDATA_PREFIX) == 0) {
 124                         const char * const type_str = specifier + sizeof_string(LOG_MDNS_SPECIFIER_RDATA_PREFIX);
 125                         const int type_value = DNSRecordTypeStringToValue(type_str);
 126                         if (type_value != 0) {
 127                                 return _log_mdns_format_record_data(data, type_value);
 128                         }
 129                 } else {
 130                         const log_mdns_data_formatter_item_t log_mdns_data_formatter_table[] = {
 131                                 { LOG_MDNS_SPECIFIER_DNS_MESSAGE,                _log_mdns_format_dns_message },
 132                                 { LOG_MDNS_SPECIFIER_DNS_MESSAGE_HEADER, _log_mdns_format_dns_message_header },
 133                                 LOG_MDNS_RDATA_FORMATTER_ITEM(DNSKEY),
 134                                 LOG_MDNS_RDATA_FORMATTER_ITEM(DS),
 135                                 LOG_MDNS_RDATA_FORMATTER_ITEM(NSEC),
 136                                 LOG_MDNS_RDATA_FORMATTER_ITEM(NSEC3),
 137                                 LOG_MDNS_RDATA_FORMATTER_ITEM(RRSIG)
 138                         };
 139                         for (size_t i = 0; i < countof(log_mdns_data_formatter_table); ++i) {
 140                                 const log_mdns_data_formatter_item_t * const item = &log_mdns_data_formatter_table[i];
 141                                 if (strcasecmp(specifier, item->specifier) == 0) {
 142                                         return item->formatter(data);
 143                                 }
 144                         }
 145                 }
 146         } else if ([arg isKindOfClass:[NSNumber class]]) {
 147                 const log_mdns_number_formatter_item_t log_mdns_number_formatter_table[] = {
 148                         { LOG_MDNS_SPECIFIER_ERROR,                             _log_mdns_format_err },
 149                         { LOG_MDNS_SPECIFIER_DNS_RECORD_TYPE,   _log_mdns_format_dns_record_type }
 150                 };
 151                 NSNumber * const number = (NSNumber *)arg;
 152                 for (size_t i = 0; i < countof(log_mdns_number_formatter_table); ++i) {
 153                         const log_mdns_number_formatter_item_t * const item = &log_mdns_number_formatter_table[i];
 154                         if (strcasecmp(specifier, item->specifier) == 0) {
 155                                 return item->formatter(number);
 156                         }
 157                 }
 158         }
 159         return nil;
 160 }
 161
 162 //======================================================================================================================
 163 // MARK: - Internal Functions
 164
 165 static NSAttributedString *
 166 _log_mdns_format_dns_message(NSData * const data)
 167 {
 168         return _log_mdns_format_dns_message_ex(data, kDNSMessageToStringFlag_Null);
 169 }
 170
 171 //======================================================================================================================
 172
 173 static NSAttributedString *
 174 _log_mdns_format_dns_message_header(NSData * const data)
 175 {
 176         return _log_mdns_format_dns_message_ex(data, kDNSMessageToStringFlag_HeaderOnly);
 177 }
 178
 179 //======================================================================================================================
 180
 181 static NSAttributedString *
 182 _log_mdns_format_err(NSNumber * const number)
 183 {
 184         return NSPrintTypedObject("err", number, NULL);
 185 }
 186
 187 //======================================================================================================================
 188
 189 static NSAttributedString *
 190 _log_mdns_format_dns_record_type(NSNumber * const number)
 191 {
 192         unsigned long long value = [number unsignedLongLongValue];
 193         require_return_value(value <= INT_MAX, nil);
 194
 195         NSString *nsstr;
 196         const char *cstr = DNSRecordTypeValueToString((int)value);
 197         if (cstr) {
 198                 nsstr = [[NSString alloc] initWithFormat:@"%s", cstr];
 199                 require_return_value(nsstr, nil);
 200         } else {
 201                 nsstr = [[NSString alloc] initWithFormat:@"TYPE%u", (unsigned int)value];
 202                 require_return_value(nsstr, nil);
 203         }
 204         return [[NSAttributedString alloc] initWithString:nsstr];
 205 }
 206
 207 //======================================================================================================================
 208
 209 static NSAttributedString *
 210 _log_mdns_format_record_data(NSData * const rdata, const int record_type)
 211 {
 212         char *cstr = NULL;
 213         DNSRecordDataToString(rdata.bytes, rdata.length, record_type, &cstr);
 214         if (!cstr) {
 215                 return nil;
 216         }
 217         const size_t len = strlen(cstr);
 218         NSString * const nsstr = [[NSString alloc] initWithBytesNoCopy:cstr length:len encoding:NSUTF8StringEncoding
 219                 freeWhenDone:YES];
 220         if (!nsstr) {
 221                 ForgetMem(&cstr);
 222                 return nil;
 223         }
 224         return [[NSAttributedString alloc] initWithString:nsstr];
 225 }
 226
 227 //======================================================================================================================
 228
 229 static NSAttributedString *
 230 _log_mdns_format_dns_message_ex(NSData * const data, const DNSMessageToStringFlags extra_flags)
 231 {
 232         char *msg_cstr = NULL;
 233         const DNSMessageToStringFlags flags = kDNSMessageToStringFlag_OneLine | extra_flags;
 234         DNSMessageToString(data.bytes, data.length, flags, &msg_cstr);
 235         require_return_value(msg_cstr, nil);
 236
 237         NSString *msg_nsstr = [[NSString alloc] initWithBytesNoCopy:msg_cstr length:strlen(msg_cstr)
 238                 encoding:NSUTF8StringEncoding freeWhenDone:YES];
 239         require_return_value_action(msg_nsstr, nil, ForgetMem(&msg_cstr));
 240
 241         return [[NSAttributedString alloc] initWithString:msg_nsstr];
 242 }