xref: /aosp_15_r20/external/mdnsresponder/mDNSShared/PlatformCommon.c (revision 48a54d368dc4fa860885eef7b70b6c53499e7c25)
1 /* -*- Mode: C; tab-width: 4 -*-
2  *
3  * Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  *     http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 
18 #include <stdio.h>				// Needed for fopen() etc.
19 #include <unistd.h>				// Needed for close()
20 #include <string.h>				// Needed for strlen() etc.
21 #include <errno.h>				// Needed for errno etc.
22 #include <sys/socket.h>			// Needed for socket() etc.
23 #include <netinet/in.h>			// Needed for sockaddr_in
24 #include <syslog.h>
25 
26 #include "mDNSEmbeddedAPI.h"	// Defines the interface provided to the client layer above
27 #include "DNSCommon.h"
28 #include "PlatformCommon.h"
29 
30 #ifdef __ANDROID__
31 #include <android/log.h>
32 #endif
33 
34 #ifdef NOT_HAVE_SOCKLEN_T
35     typedef unsigned int socklen_t;
36 #endif
37 
38 // Bind a UDP socket to find the source address to a destination
mDNSPlatformSourceAddrForDest(mDNSAddr * const src,const mDNSAddr * const dst)39 mDNSexport void mDNSPlatformSourceAddrForDest(mDNSAddr *const src, const mDNSAddr *const dst)
40 	{
41 	union { struct sockaddr s; struct sockaddr_in a4; struct sockaddr_in6 a6; } addr;
42 	socklen_t len = sizeof(addr);
43 	socklen_t inner_len = 0;
44 	int sock = socket(AF_INET, SOCK_DGRAM, 0);
45 	src->type = mDNSAddrType_None;
46 	if (sock == -1) return;
47 	if (dst->type == mDNSAddrType_IPv4)
48 		{
49 		inner_len = sizeof(addr.a4);
50 		#ifndef NOT_HAVE_SA_LEN
51 		addr.a4.sin_len         = inner_len;
52 		#endif
53 		addr.a4.sin_family      = AF_INET;
54 		addr.a4.sin_port        = 1;	// Not important, any port will do
55 		addr.a4.sin_addr.s_addr = dst->ip.v4.NotAnInteger;
56 		}
57 	else if (dst->type == mDNSAddrType_IPv6)
58 		{
59 		inner_len = sizeof(addr.a6);
60 		#ifndef NOT_HAVE_SA_LEN
61 		addr.a6.sin6_len      = inner_len;
62 		#endif
63 		addr.a6.sin6_family   = AF_INET6;
64 		addr.a6.sin6_flowinfo = 0;
65 		addr.a6.sin6_port     = 1;	// Not important, any port will do
66 		addr.a6.sin6_addr     = *(struct in6_addr*)&dst->ip.v6;
67 		addr.a6.sin6_scope_id = 0;
68 		}
69 	else
70 		{
71 		// __ANDROID__ : Fix fd leak
72 		goto exit;
73 		}
74 
75 
76 	if ((connect(sock, &addr.s, inner_len)) < 0)
77 		{ LogMsg("mDNSPlatformSourceAddrForDest: connect %#a failed errno %d (%s)", dst, errno, strerror(errno)); goto exit; }
78 
79 	if ((getsockname(sock, &addr.s, &len)) < 0)
80 		{ LogMsg("mDNSPlatformSourceAddrForDest: getsockname failed errno %d (%s)", errno, strerror(errno)); goto exit; }
81 
82 	src->type = dst->type;
83 	if (dst->type == mDNSAddrType_IPv4) src->ip.v4.NotAnInteger = addr.a4.sin_addr.s_addr;
84 	else                                src->ip.v6 = *(mDNSv6Addr*)&addr.a6.sin6_addr;
85 exit:
86 	close(sock);
87 	}
88 
89 // dst must be at least MAX_ESCAPED_DOMAIN_NAME bytes, and option must be less than 32 bytes in length
GetConfigOption(char * dst,const char * option,FILE * f)90 mDNSlocal mDNSBool GetConfigOption(char *dst, const char *option, FILE *f)
91 	{
92 	char buf[32+1+MAX_ESCAPED_DOMAIN_NAME];	// Option name, one space, option value
93 	unsigned int len = strlen(option);
94 	if (len + 1 + MAX_ESCAPED_DOMAIN_NAME > sizeof(buf)-1) { LogMsg("GetConfigOption: option %s too long", option); return mDNSfalse; }
95 	fseek(f, 0, SEEK_SET);  // set position to beginning of stream
96 	while (fgets(buf, sizeof(buf), f))		// Read at most sizeof(buf)-1 bytes from file, and append '\0' C-string terminator
97 		{
98 		if (!strncmp(buf, option, len))
99 			{
100 			strncpy(dst, buf + len + 1, MAX_ESCAPED_DOMAIN_NAME-1);
101 			if (dst[MAX_ESCAPED_DOMAIN_NAME-1]) dst[MAX_ESCAPED_DOMAIN_NAME-1] = '\0';
102 			len = strlen(dst);
103 			if (len && dst[len-1] == '\n') dst[len-1] = '\0';  // chop newline
104 			return mDNStrue;
105 			}
106 		}
107 	debugf("Option %s not set", option);
108 	return mDNSfalse;
109 	}
110 
ReadDDNSSettingsFromConfFile(mDNS * const m,const char * const filename,domainname * const hostname,domainname * const domain,mDNSBool * DomainDiscoveryDisabled)111 mDNSexport void ReadDDNSSettingsFromConfFile(mDNS *const m, const char *const filename, domainname *const hostname, domainname *const domain, mDNSBool *DomainDiscoveryDisabled)
112 	{
113 	char buf[MAX_ESCAPED_DOMAIN_NAME] = "";
114 	mStatus err;
115 	FILE *f = fopen(filename, "r");
116 
117     if (hostname)                 hostname->c[0] = 0;
118     if (domain)                   domain->c[0] = 0;
119 	if (DomainDiscoveryDisabled) *DomainDiscoveryDisabled = mDNSfalse;
120 
121 	if (f)
122 		{
123 		if (DomainDiscoveryDisabled && GetConfigOption(buf, "DomainDiscoveryDisabled", f) && !strcasecmp(buf, "true")) *DomainDiscoveryDisabled = mDNStrue;
124 		if (hostname && GetConfigOption(buf, "hostname", f) && !MakeDomainNameFromDNSNameString(hostname, buf)) goto badf;
125 		if (domain && GetConfigOption(buf, "zone", f) && !MakeDomainNameFromDNSNameString(domain, buf)) goto badf;
126 		buf[0] = 0;
127 		GetConfigOption(buf, "secret-64", f);  // failure means no authentication
128 		fclose(f);
129 		f = NULL;
130 		}
131 	else
132 		{
133 		if (errno != ENOENT) LogMsg("ERROR: Config file exists, but cannot be opened.");
134 		return;
135 		}
136 
137 	if (domain && domain->c[0] && buf[0])
138 		{
139 		DomainAuthInfo *info = (DomainAuthInfo*)mDNSPlatformMemAllocate(sizeof(*info));
140 		// for now we assume keyname = service reg domain and we use same key for service and hostname registration
141 		err = mDNS_SetSecretForDomain(m, info, domain, domain, buf, NULL, 0, NULL);
142 		if (err) LogMsg("ERROR: mDNS_SetSecretForDomain returned %d for domain %##s", err, domain->c);
143 		}
144 
145 	return;
146 
147 	badf:
148 	LogMsg("ERROR: malformatted config file");
149 	if (f) fclose(f);
150 	}
151 
152 #if MDNS_DEBUGMSGS
mDNSPlatformWriteDebugMsg(const char * msg)153 mDNSexport void mDNSPlatformWriteDebugMsg(const char *msg)
154 	{
155 #ifdef __ANDROID__
156 	__android_log_print(ANDROID_LOG_DEBUG, "mdns", "%s", msg);
157 #else
158 	fprintf(stderr,"%s\n", msg);
159 	fflush(stderr);
160 #endif
161 	}
162 #endif
163 
mDNSPlatformWriteLogMsg(const char * ident,const char * buffer,mDNSLogLevel_t loglevel)164 mDNSexport void mDNSPlatformWriteLogMsg(const char *ident, const char *buffer, mDNSLogLevel_t loglevel)
165 	{
166 #if APPLE_OSX_mDNSResponder && LogTimeStamps
167 	extern mDNS mDNSStorage;
168 	extern mDNSu32 mDNSPlatformClockDivisor;
169 	mDNSs32 t = mDNSStorage.timenow ? mDNSStorage.timenow : mDNSPlatformClockDivisor ? mDNS_TimeNow_NoLock(&mDNSStorage) : 0;
170 	int ms = ((t < 0) ? -t : t) % 1000;
171 #endif
172 
173 	if (mDNS_DebugMode)	// In debug mode we write to stderr
174 		{
175 #if APPLE_OSX_mDNSResponder && LogTimeStamps
176 		if (ident && ident[0] && mDNSPlatformClockDivisor)
177 			fprintf(stderr,"%8d.%03d: %s\n", (int)(t/1000), ms, buffer);
178 		else
179 #endif
180 			fprintf(stderr,"%s\n", buffer);
181 		fflush(stderr);
182 		}
183 	else				// else, in production mode, we write to syslog
184 		{
185 		static int log_inited = 0;
186 
187 		int syslog_level = LOG_ERR;
188 		switch (loglevel)
189 			{
190 			case MDNS_LOG_MSG:       syslog_level = LOG_ERR;     break;
191 			case MDNS_LOG_OPERATION: syslog_level = LOG_WARNING; break;
192 			case MDNS_LOG_SPS:       syslog_level = LOG_NOTICE;  break;
193 			case MDNS_LOG_INFO:      syslog_level = LOG_INFO;    break;
194 			case MDNS_LOG_DEBUG:     syslog_level = LOG_DEBUG;   break;
195 			default:
196 			fprintf(stderr, "Unknown loglevel %d, assuming LOG_ERR\n", loglevel);
197 			fflush(stderr);
198 			}
199 
200 		if (!log_inited) { openlog(ident, LOG_CONS, LOG_DAEMON); log_inited++; }
201 
202 #if APPLE_OSX_mDNSResponder && LogTimeStamps
203 		if (ident && ident[0] && mDNSPlatformClockDivisor)
204 			syslog(syslog_level, "%8d.%03d: %s", (int)(t/1000), ms, buffer);
205 		else
206 #endif
207 #ifdef __ANDROID__
208 		switch (loglevel)
209 			{
210 			case MDNS_LOG_DEBUG:     syslog_level = ANDROID_LOG_DEBUG;  break;
211 #if MDNS_DEBUGMSGS > 0
212 			case MDNS_LOG_OPERATION: syslog_level = ANDROID_LOG_WARN;   break;
213 			case MDNS_LOG_SPS:       syslog_level = ANDROID_LOG_DEBUG;  break;
214 			case MDNS_LOG_INFO:      syslog_level = ANDROID_LOG_INFO;   break;
215 			default:                 syslog_level = ANDROID_LOG_ERROR;  break;
216 #else
217 			default:		return;
218 #endif
219 			}
220 		__android_log_print(syslog_level, "mdns", "%s", buffer);
221 #else
222 			syslog(syslog_level, "%s", buffer);
223 #endif
224 		}
225 	}
226