mDNSMacOSX/mdns_objects/mdns_powerlog.c

   1 /*
   2  * Copyright (c) 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 #include "mdns_powerlog.h"
  18 #include "mdns_helpers.h"
  19
  20 #include "DNSMessage.h"
  21
  22 #include <CoreUtils/CoreUtils.h>
  23 #include <libproc.h>
  24 #include <os/log.h>
  25 #include <PowerLog/PowerLog.h>
  26 #include <SoftLinking/WeakLinking.h>
  27 #include <sys/proc_info.h>
  28
  29 //======================================================================================================================
  30 // MARK: - Weak Linking
  31
  32 WEAK_LINK_FORCE_IMPORT(PLLogRegisteredEvent); // The PowerLog framework isn't present in the BaseSystem
  33
  34 //======================================================================================================================
  35 // MARK: - PowerLog Event Names
  36
  37 #define MDNS_POWERLOG_EVENT_AWDL_BROWSE_START           CFSTR("startAWDLBrowse")
  38 #define MDNS_POWERLOG_EVENT_AWDL_BROWSE_STOP            CFSTR("stopAWDLBrowse")
  39 #define MDNS_POWERLOG_EVENT_AWDL_ADVERTISE_START        CFSTR("startAWDLAdvertise")
  40 #define MDNS_POWERLOG_EVENT_AWDL_ADVERTISE_STOP         CFSTR("stopAWDLAdvertise")
  41 #define MDNS_POWERLOG_EVENT_AWDL_RESOLVE_START          CFSTR("startAWDLResolve")
  42 #define MDNS_POWERLOG_EVENT_AWDL_RESOLVE_STOP           CFSTR("stopAWDLResolve")
  43
  44 //======================================================================================================================
  45 // MARK: - PowerLog Event Dictionary Keys
  46
  47 #define MDNS_POWERLOG_EVENT_KEY_SERVICE_TYPE    CFSTR("service")        // String: Service name w/protocol, e.g., _ssh._tcp.
  48 #define MDNS_POWERLOG_EVENT_KEY_RECORD_TYPE             CFSTR("recordType")     // String: Record type, e.g., PTR, SRV, A.
  49 #define MDNS_POWERLOG_EVENT_KEY_CLIENT_PID              CFSTR("clientPID")      // Number: Client's PID.
  50 #define MDNS_POWERLOG_EVENT_KEY_CLIENT_NAME             CFSTR("clientName")     // String: Client's process name.
  51
  52 //======================================================================================================================
  53 // MARK: - Helper Prototypes
  54
  55 static void
  56 _mdns_powerlog_bonjour_event(CFStringRef event_name, const uint8_t *record_name, int record_type, pid_t client_pid);
  57
  58 //======================================================================================================================
  59 // MARK: - Debug Logging
  60
  61 // The purpose of this os_log category is to log debug messages about logging to PowerLog.
  62 // It has nothing to do with actually logging to PowerLog.
  63 MDNS_LOG_CATEGORY_DEFINE(powerlog, "powerlog");
  64
  65 //======================================================================================================================
  66 // MARK: - External Functions
  67
  68 void
  69 mdns_powerlog_awdl_browse_start(const uint8_t * const record_name, const int record_type, const pid_t client_pid)
  70 {
  71         _mdns_powerlog_bonjour_event(MDNS_POWERLOG_EVENT_AWDL_BROWSE_START, record_name, record_type, client_pid);
  72 }
  73
  74 //======================================================================================================================
  75
  76 void
  77 mdns_powerlog_awdl_browse_stop(const uint8_t * const record_name, const int record_type, const pid_t client_pid)
  78 {
  79         _mdns_powerlog_bonjour_event(MDNS_POWERLOG_EVENT_AWDL_BROWSE_STOP, record_name, record_type, client_pid);
  80 }
  81
  82 //======================================================================================================================
  83
  84 void
  85 mdns_powerlog_awdl_advertise_start(const uint8_t * const record_name, const int record_type, const pid_t client_pid)
  86 {
  87         _mdns_powerlog_bonjour_event(MDNS_POWERLOG_EVENT_AWDL_ADVERTISE_START, record_name, record_type, client_pid);
  88 }
  89
  90 //======================================================================================================================
  91
  92 void
  93 mdns_powerlog_awdl_advertise_stop(const uint8_t * const record_name, const int record_type, const pid_t client_pid)
  94 {
  95         _mdns_powerlog_bonjour_event(MDNS_POWERLOG_EVENT_AWDL_ADVERTISE_STOP, record_name, record_type, client_pid);
  96 }
  97
  98 //======================================================================================================================
  99
 100 void
 101 mdns_powerlog_awdl_resolve_start(const uint8_t * const record_name, const int record_type, const pid_t client_pid)
 102 {
 103         _mdns_powerlog_bonjour_event(MDNS_POWERLOG_EVENT_AWDL_RESOLVE_START, record_name, record_type, client_pid);
 104 }
 105
 106 //======================================================================================================================
 107
 108 void
 109 mdns_powerlog_awdl_resolve_stop(const uint8_t * const record_name, const int record_type, const pid_t client_pid)
 110 {
 111         _mdns_powerlog_bonjour_event(MDNS_POWERLOG_EVENT_AWDL_RESOLVE_STOP, record_name, record_type, client_pid);
 112 }
 113
 114 //======================================================================================================================
 115 // MARK: - Helpers
 116
 117 static CFDictionaryRef
 118 _mdns_powerlog_create_event_dictionary(const uint8_t *record_name, int record_type, pid_t client_pid);
 119
 120 static void
 121 _mdns_powerlog_bonjour_event(const CFStringRef event_name, const uint8_t * const record_name, const int record_type,
 122         const pid_t client_pid)
 123 {
 124         require_quiet(PLLogRegisteredEvent, exit);
 125
 126         const PLClientID plc_id = PLClientIDMDNSResponder;
 127         const CFDictionaryRef event_dict = _mdns_powerlog_create_event_dictionary(record_name, record_type, client_pid);
 128         os_log_debug(_mdns_powerlog_log(),
 129                 "Logging to powerlog -- id: %ld, event: %@, dictionary: %@", (long)plc_id, event_name, event_dict);
 130         PLLogRegisteredEvent(plc_id, event_name, event_dict, NULL);
 131         CFReleaseNullSafe(event_dict);
 132
 133 exit:
 134         return;
 135 }
 136
 137 //======================================================================================================================
 138
 139 static void
 140 _mdns_powerlog_event_dictionary_add_service_type(CFMutableDictionaryRef event_dict, const uint8_t *record_name);
 141
 142 static void
 143 _mdns_powerlog_event_dictionary_add_record_type(CFMutableDictionaryRef event_dict, int record_type);
 144
 145 static void
 146 _mdns_powerlog_event_dictionary_add_client_info(CFMutableDictionaryRef event_dict, pid_t client_pid);
 147
 148 static CFDictionaryRef
 149 _mdns_powerlog_create_event_dictionary(const uint8_t * const record_name, const int record_type,
 150         const pid_t client_pid)
 151 {
 152         CFMutableDictionaryRef event_dict = CFDictionaryCreateMutable(NULL, 0, &kCFTypeDictionaryKeyCallBacks,
 153                 &kCFTypeDictionaryValueCallBacks);
 154         require_quiet(event_dict, exit);
 155
 156         _mdns_powerlog_event_dictionary_add_service_type(event_dict, record_name);
 157         _mdns_powerlog_event_dictionary_add_record_type(event_dict, record_type);
 158         _mdns_powerlog_event_dictionary_add_client_info(event_dict, client_pid);
 159
 160 exit:
 161         return event_dict;
 162 }
 163
 164 //======================================================================================================================
 165
 166 static char *
 167 _mdns_get_service_name_string_from_domain_name(const uint8_t *name,
 168         char service_name_str[static kDNSServiceMaxDomainName]);
 169
 170 static void
 171 _mdns_powerlog_event_dictionary_add_service_type(const CFMutableDictionaryRef event_dict,
 172         const uint8_t * const record_name)
 173 {
 174         char service_type[kDNSServiceMaxDomainName];
 175         if (_mdns_get_service_name_string_from_domain_name(record_name, service_type)) {
 176                 CFStringRef service_type_value = CFStringCreateWithCString(NULL, service_type, kCFStringEncodingUTF8);
 177                 if (service_type_value) {
 178                         CFDictionaryAddValue(event_dict, MDNS_POWERLOG_EVENT_KEY_SERVICE_TYPE, service_type_value);
 179                         ForgetCF(&service_type_value);
 180                 }
 181         }
 182 }
 183
 184 #define MDNS_TCP_PROTOCOL_LABEL ((const uint8_t *)"\x4" "_tcp")
 185 #define MDNS_UDP_PROTOCOL_LABEL ((const uint8_t *)"\x4" "_udp")
 186 #define MDNS_LOCAL_DOMAIN_NAME  ((const uint8_t *)"\x5" "local")
 187
 188 static char *
 189 _mdns_get_service_name_string_from_domain_name(const uint8_t * const record_name,
 190         char service_name_str[static kDNSServiceMaxDomainName])
 191 {
 192         size_t len;
 193         const uint8_t *l1 = NULL;
 194         const uint8_t *l2 = NULL;
 195         const uint8_t *l3 = NULL;
 196         // Get the three labels leading up to the root label.
 197         for (const uint8_t *ptr = record_name; (len = *ptr) != 0; ptr = &ptr[1 + len]) {
 198                 l1 = l2;
 199                 l2 = l3;
 200                 l3 = ptr;
 201         }
 202         // Make sure the first label begins with '_', the second label is '_tcp' or '_udp', and the third label is 'local'.
 203         // See <https://tools.ietf.org/html/rfc6763#section-4.1.2>.
 204         char *result = NULL;
 205         if (l1 && (l1[1] == '_') &&
 206                 l2 && (DomainLabelEqual(l2, MDNS_TCP_PROTOCOL_LABEL) || DomainLabelEqual(l2, MDNS_UDP_PROTOCOL_LABEL)) &&
 207                 l3 && DomainNameEqual(l3, MDNS_LOCAL_DOMAIN_NAME)) {
 208                 uint8_t service_name[kDomainNameLengthMax];
 209                 uint8_t *ptr = service_name;
 210                 const uint8_t * const limit = &service_name[countof(service_name)];
 211
 212                 // Append service name label.
 213                 len = 1 + l1[0];
 214                 require_quiet(((size_t)(limit - ptr)) >= len, exit);
 215                 memcpy(ptr, l1, len);
 216                 ptr += len;
 217
 218                 // Append protocol label, i.e., '_tcp' or '_udp'.
 219                 len = 1 + l2[0];
 220                 require_quiet(((size_t)(limit - ptr)) >= len, exit);
 221                 memcpy(ptr, l2, len);
 222                 ptr += len;
 223
 224                 // Append root label.
 225                 require_quiet((limit - ptr) >= 1, exit);
 226                 *ptr = 0;
 227
 228                 // Convert to string.
 229                 const OSStatus err = DomainNameToString(service_name, limit, service_name_str, NULL);
 230                 if (!err) {
 231                         // Remove trailing root dot.
 232                         len = strlen(service_name_str);
 233                         if (len > 0) {
 234                                 char * const cptr = &service_name_str[len - 1];
 235                                 if (*cptr == '.') {
 236                                         *cptr = '\0';
 237                                 }
 238                         }
 239                         result = service_name_str;
 240                 }
 241         }
 242
 243 exit:
 244         return result;
 245 }
 246
 247 //======================================================================================================================
 248
 249 static void
 250 _mdns_powerlog_event_dictionary_add_record_type(const CFMutableDictionaryRef event_dict, const int record_type)
 251 {
 252         char qtype_str_buf[32];
 253         const char *qtype_str = DNSRecordTypeValueToString(record_type);
 254         if (!qtype_str) {
 255                 snprintf(qtype_str_buf, sizeof(qtype_str_buf), "TYPE%d", record_type);
 256                 qtype_str = qtype_str_buf;
 257         }
 258         CFStringRef qtype_str_value = CFStringCreateWithCString(NULL, qtype_str, kCFStringEncodingUTF8);
 259         if (qtype_str_value) {
 260                 CFDictionaryAddValue(event_dict, MDNS_POWERLOG_EVENT_KEY_RECORD_TYPE, qtype_str_value);
 261                 ForgetCF(&qtype_str_value);
 262         }
 263 }
 264
 265 //======================================================================================================================
 266
 267 static char *
 268 _mdns_pid_to_name(pid_t pid, char name[STATIC_PARAM MAXCOMLEN]);
 269
 270 static void
 271 _mdns_powerlog_event_dictionary_add_client_info(const CFMutableDictionaryRef event_dict, const pid_t client_pid)
 272 {
 273         const long long client_pid_ll = client_pid;
 274         CFNumberRef client_pid_value = CFNumberCreate(NULL, kCFNumberLongLongType, &client_pid_ll);
 275         if (client_pid_value != NULL) {
 276                 CFDictionaryAddValue(event_dict, MDNS_POWERLOG_EVENT_KEY_CLIENT_PID, client_pid_value);
 277                 ForgetCF(&client_pid_value);
 278         }
 279         char client_name[MAXCOMLEN];
 280         if (_mdns_pid_to_name(client_pid, client_name)) {
 281                 CFStringRef client_name_value = CFStringCreateWithCString(NULL, client_name, kCFStringEncodingUTF8);
 282                 if (client_name_value) {
 283                         CFDictionaryAddValue(event_dict, MDNS_POWERLOG_EVENT_KEY_CLIENT_NAME, client_name_value);
 284                         ForgetCF(&client_name_value);
 285                 }
 286         }
 287 }
 288
 289 static char *
 290 _mdns_pid_to_name(const pid_t pid, char name[STATIC_PARAM MAXCOMLEN])
 291 {
 292         if (pid != 0) {
 293                 struct proc_bsdshortinfo info;
 294                 const int n = proc_pidinfo(pid, PROC_PIDT_SHORTBSDINFO, 1, &info, PROC_PIDT_SHORTBSDINFO_SIZE);
 295                 if (n == (int)sizeof(info)) {
 296                         strlcpy(name, info.pbsi_comm, MAXCOMLEN);
 297                         return name;
 298                 }
 299         }
 300         return NULL;
 301 }