mDNSShared/dnssd_ipc.c

   1 /*
   2  * Copyright (c) 2003-2020 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are met:
   6  *
   7  * 1.  Redistributions of source code must retain the above copyright notice,
   8  *     this list of conditions and the following disclaimer.
   9  * 2.  Redistributions in binary form must reproduce the above copyright notice,
  10  *     this list of conditions and the following disclaimer in the documentation
  11  *     and/or other materials provided with the distribution.
  12  * 3.  Neither the name of Apple Inc. ("Apple") nor the names of its
  13  *     contributors may be used to endorse or promote products derived from this
  14  *     software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  17  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  20  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  23  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  25  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "dnssd_ipc.h"
  29 #if APPLE_OSX_mDNSResponder
  30 #include "mdns_tlv.h"
  31 #endif
  32
  33 #if defined(_WIN32)
  34
  35 char *win32_strerror(int inErrorCode)
  36 {
  37     static char buffer[1024];
  38     DWORD n;
  39     memset(buffer, 0, sizeof(buffer));
  40     n = FormatMessageA(
  41         FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
  42         NULL,
  43         (DWORD) inErrorCode,
  44         MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
  45         buffer,
  46         sizeof(buffer),
  47         NULL);
  48     if (n > 0)
  49     {
  50         // Remove any trailing CR's or LF's since some messages have them.
  51         while ((n > 0) && isspace(((unsigned char *) buffer)[n - 1]))
  52             buffer[--n] = '\0';
  53     }
  54     return buffer;
  55 }
  56
  57 #endif
  58
  59 void put_uint32(const uint32_t l, char **ptr)
  60 {
  61     (*ptr)[0] = (char)((l >> 24) &  0xFF);
  62     (*ptr)[1] = (char)((l >> 16) &  0xFF);
  63     (*ptr)[2] = (char)((l >>  8) &  0xFF);
  64     (*ptr)[3] = (char)((l      ) &  0xFF);
  65     *ptr += sizeof(uint32_t);
  66 }
  67
  68 uint32_t get_uint32(const char **ptr, const char *end)
  69 {
  70     if (!*ptr || *ptr + sizeof(uint32_t) > end)
  71     {
  72         *ptr = NULL;
  73         return(0);
  74     }
  75     else
  76     {
  77         uint8_t *p = (uint8_t*) *ptr;
  78         *ptr += sizeof(uint32_t);
  79         return((uint32_t) ((uint32_t)p[0] << 24 | (uint32_t)p[1] << 16 | (uint32_t)p[2] << 8 | p[3]));
  80     }
  81 }
  82
  83 void put_uint16(uint16_t s, char **ptr)
  84 {
  85     (*ptr)[0] = (char)((s >>  8) &  0xFF);
  86     (*ptr)[1] = (char)((s      ) &  0xFF);
  87     *ptr += sizeof(uint16_t);
  88 }
  89
  90 uint16_t get_uint16(const char **ptr, const char *end)
  91 {
  92     if (!*ptr || *ptr + sizeof(uint16_t) > end)
  93     {
  94         *ptr = NULL;
  95         return(0);
  96     }
  97     else
  98     {
  99         uint8_t *p = (uint8_t*) *ptr;
 100         *ptr += sizeof(uint16_t);
 101         return((uint16_t) ((uint16_t)p[0] << 8 | p[1]));
 102     }
 103 }
 104
 105 int put_string(const char *str, char **ptr)
 106 {
 107     size_t len;
 108     if (!str) str = "";
 109     len = strlen(str) + 1;
 110     memcpy(*ptr, str, len);
 111     *ptr += len;
 112     return 0;
 113 }
 114
 115 int get_string(const char **ptr, const char *const end, char *buffer, int buflen)
 116 {
 117     if (!*ptr)
 118     {
 119         *buffer = 0;
 120         return(-1);
 121     }
 122     else
 123     {
 124         char *lim = buffer + buflen;    // Calculate limit
 125         while (*ptr < end && buffer < lim)
 126         {
 127             char c = *buffer++ = *(*ptr)++;
 128             if (c == 0) return(0);      // Success
 129         }
 130         if (buffer == lim) buffer--;
 131         *buffer = 0;                    // Failed, so terminate string,
 132         *ptr = NULL;                    // clear pointer,
 133         return(-1);                     // and return failure indication
 134     }
 135 }
 136
 137 void put_rdata(const int rdlen, const unsigned char *rdata, char **ptr)
 138 {
 139     memcpy(*ptr, rdata, rdlen);
 140     *ptr += rdlen;
 141 }
 142
 143 const char *get_rdata(const char **ptr, const char *end, int rdlen)
 144 {
 145     if (!*ptr || *ptr + rdlen > end)
 146     {
 147         *ptr = NULL;
 148         return(0);
 149     }
 150     else
 151     {
 152         const char *rd = *ptr;
 153         *ptr += rdlen;
 154         return rd;
 155     }
 156 }
 157
 158 #if APPLE_OSX_mDNSResponder
 159 size_t get_required_tlv16_length(const uint16_t valuelen)
 160 {
 161     return mdns_tlv16_get_required_length(valuelen);
 162 }
 163
 164 void put_tlv16(const uint16_t type, const uint16_t length, const uint8_t *value, char **ptr)
 165 {
 166         uint8_t *dst = (uint8_t *)*ptr;
 167         mdns_tlv16_set(dst, NULL, type, length, value, &dst);
 168     *ptr = (char *)dst;
 169 }
 170 #endif
 171
 172 void ConvertHeaderBytes(ipc_msg_hdr *hdr)
 173 {
 174     hdr->version   = htonl(hdr->version);
 175     hdr->datalen   = htonl(hdr->datalen);
 176     hdr->ipc_flags = htonl(hdr->ipc_flags);
 177     hdr->op        = htonl(hdr->op );
 178     hdr->reg_index = htonl(hdr->reg_index);
 179 }