1 | /* $Id: pxdns.c 106061 2024-09-16 14:03:52Z vboxsync $ */
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2 | /** @file
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3 | * NAT Network - DNS proxy.
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2009-2024 Oracle and/or its affiliates.
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8 | *
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9 | * This file is part of VirtualBox base platform packages, as
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10 | * available from https://www.virtualbox.org.
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11 | *
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12 | * This program is free software; you can redistribute it and/or
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13 | * modify it under the terms of the GNU General Public License
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14 | * as published by the Free Software Foundation, in version 3 of the
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15 | * License.
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16 | *
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17 | * This program is distributed in the hope that it will be useful, but
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18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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20 | * General Public License for more details.
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21 | *
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22 | * You should have received a copy of the GNU General Public License
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23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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24 | *
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25 | * SPDX-License-Identifier: GPL-3.0-only
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26 | */
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27 |
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28 | /*
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29 | * Copyright (c) 2003,2004,2005 Armin Wolfermann
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30 | *
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31 | * Permission is hereby granted, free of charge, to any person obtaining a
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32 | * copy of this software and associated documentation files (the "Software"),
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33 | * to deal in the Software without restriction, including without limitation
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34 | * the rights to use, copy, modify, merge, publish, distribute, sublicense,
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35 | * and/or sell copies of the Software, and to permit persons to whom the
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36 | * Software is furnished to do so, subject to the following conditions:
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37 | *
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38 | * The above copyright notice and this permission notice shall be included in
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39 | * all copies or substantial portions of the Software.
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40 | *
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41 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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42 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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43 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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44 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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45 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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46 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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47 | * DEALINGS IN THE SOFTWARE.
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48 | */
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49 | #define LOG_GROUP LOG_GROUP_NAT_SERVICE
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50 |
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51 | #include "winutils.h"
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52 |
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53 | #include "proxy.h"
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54 | #include "proxy_pollmgr.h"
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55 | #include "pxtcp.h"
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56 |
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57 | #include "lwip/sys.h"
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58 | #include "lwip/tcpip.h"
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59 | #include "lwip/ip_addr.h"
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60 | #include "lwip/udp.h"
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61 | #include "lwip/tcp.h"
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62 |
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63 | #ifndef RT_OS_WINDOWS
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64 | #include <sys/poll.h>
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65 | #include <sys/socket.h>
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66 | #include <netinet/in.h>
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67 | #include <netdb.h>
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68 | #else
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69 | #include "winpoll.h"
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70 | #endif
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71 |
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72 | #include <stdio.h>
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73 | #include <string.h>
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74 |
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75 |
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76 | union sockaddr_inet {
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77 | struct sockaddr sa;
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78 | struct sockaddr_in sin;
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79 | struct sockaddr_in6 sin6;
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80 | };
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81 |
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82 |
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83 | struct request;
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84 |
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85 |
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86 | /**
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87 | * DNS Proxy
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88 | */
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89 | struct pxdns {
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90 | SOCKET sock4;
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91 | SOCKET sock6;
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92 |
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93 | struct pollmgr_handler pmhdl4;
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94 | struct pollmgr_handler pmhdl6;
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95 |
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96 | struct udp_pcb *pcb4;
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97 | struct udp_pcb *pcb6;
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98 |
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99 | struct tcp_pcb *ltcp;
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100 |
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101 | size_t generation;
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102 | size_t nresolvers;
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103 | union sockaddr_inet *resolvers;
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104 |
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105 | u16_t id;
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106 |
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107 | sys_mutex_t lock;
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108 |
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109 | size_t active_queries;
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110 | size_t expired_queries;
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111 | size_t late_answers;
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112 | size_t hash_collisions;
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113 |
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114 | #define TIMEOUT 5
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115 | size_t timeout_slot;
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116 | u32_t timeout_mask;
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117 | struct request *timeout_list[TIMEOUT];
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118 |
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119 | #define HASHSIZE 10
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120 | #define HASH(id) ((id) & ((1 << HASHSIZE) - 1))
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121 | struct request *request_hash[1 << HASHSIZE];
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122 | } g_pxdns;
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123 |
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124 |
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125 | struct request {
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126 | /**
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127 | * Request ID that we use in relayed request.
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128 | */
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129 | u16_t id;
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130 |
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131 | /**
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132 | * pxdns::generation used for this request
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133 | */
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134 | size_t generation;
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135 |
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136 | /**
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137 | * Current index into pxdns::resolvers
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138 | */
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139 | size_t residx;
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140 |
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141 | /**
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142 | * PCB from which we have received this request. lwIP doesn't
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143 | * support listening for both IPv4 and IPv6 on the same pcb, so we
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144 | * use two and need to keep track.
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145 | */
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146 | struct udp_pcb *pcb;
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147 |
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148 | /**
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149 | * Client this request is from and its original request ID.
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150 | */
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151 | ipX_addr_t client_addr;
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152 | u16_t client_port;
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153 | u16_t client_id;
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154 |
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155 | /**
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156 | * Chaining for pxdns::request_hash
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157 | */
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158 | struct request **pprev_hash;
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159 | struct request *next_hash;
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160 |
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161 | /**
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162 | * Chaining for pxdns::timeout_list
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163 | */
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164 | struct request **pprev_timeout;
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165 | struct request *next_timeout;
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166 |
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167 | /**
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168 | * Slot in pxdns::timeout_list
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169 | */
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170 | size_t timeout_slot;
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171 |
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172 | /**
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173 | * Pbuf with reply received on pollmgr thread.
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174 | */
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175 | struct pbuf *reply;
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176 |
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177 | /**
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178 | * Preallocated lwIP message to send reply from the lwIP thread.
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179 | */
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180 | struct tcpip_msg msg_reply;
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181 |
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182 | /**
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183 | * Client request. ID is replaced with ours, original saved in
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184 | * client_id. Use a copy since we might need to resend and we
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185 | * don't want to hold onto pbuf of the request.
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186 | */
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187 | size_t size;
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188 | u8_t data[1];
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189 | };
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190 |
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191 |
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192 | static void pxdns_create_resolver_sockaddrs(struct pxdns *pxdns,
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193 | const char **nameservers);
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194 |
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195 | static err_t pxdns_accept_syn(void *arg, struct tcp_pcb *newpcb, struct pbuf *syn);
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196 |
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197 | static void pxdns_recv4(void *arg, struct udp_pcb *pcb, struct pbuf *p,
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198 | ip_addr_t *addr, u16_t port);
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199 | static void pxdns_recv6(void *arg, struct udp_pcb *pcb, struct pbuf *p,
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200 | ip6_addr_t *addr, u16_t port);
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201 | static void pxdns_query(struct pxdns *pxdns, struct udp_pcb *pcb, struct pbuf *p,
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202 | ipX_addr_t *addr, u16_t port);
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203 | static void pxdns_timer(void *arg);
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204 | static int pxdns_rexmit(struct pxdns *pxdns, struct request *req);
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205 | static int pxdns_forward_outbound(struct pxdns *pxdns, struct request *req);
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206 |
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207 | static int pxdns_pmgr_pump(struct pollmgr_handler *handler, SOCKET fd, int revents);
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208 | static void pxdns_pcb_reply(void *ctx);
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209 |
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210 | static void pxdns_request_register(struct pxdns *pxdns, struct request *req);
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211 | static void pxdns_request_deregister(struct pxdns *pxdns, struct request *req);
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212 | static struct request *pxdns_request_find(struct pxdns *pxdns, u16_t id);
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213 |
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214 | static void pxdns_hash_add(struct pxdns *pxdns, struct request *req);
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215 | static void pxdns_hash_del(struct pxdns *pxdns, struct request *req);
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216 | static void pxdns_timeout_add(struct pxdns *pxdns, struct request *req);
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217 | static void pxdns_timeout_del(struct pxdns *pxdns, struct request *req);
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218 |
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219 | static void pxdns_request_free(struct request *req);
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220 |
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221 |
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222 | err_t
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223 | pxdns_init(struct netif *proxy_netif)
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224 | {
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225 | struct pxdns *pxdns = &g_pxdns;
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226 | err_t error;
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227 |
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228 | LWIP_UNUSED_ARG(proxy_netif);
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229 |
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230 | pxdns->ltcp = tcp_new();
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231 | if (pxdns->ltcp != NULL) {
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232 | tcp_bind_ip6(pxdns->ltcp, IP6_ADDR_ANY, 53);
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233 | pxdns->ltcp = tcp_listen_dual(pxdns->ltcp);
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234 | if (pxdns->ltcp != NULL) {
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235 | tcp_arg(pxdns->ltcp, pxdns);
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236 | tcp_accept_syn(pxdns->ltcp, pxdns_accept_syn);
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237 | }
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238 | }
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239 |
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240 | pxdns->pmhdl4.callback = pxdns_pmgr_pump;
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241 | pxdns->pmhdl4.data = (void *)pxdns;
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242 | pxdns->pmhdl4.slot = -1;
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243 |
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244 | pxdns->pmhdl6.callback = pxdns_pmgr_pump;
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245 | pxdns->pmhdl6.data = (void *)pxdns;
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246 | pxdns->pmhdl6.slot = -1;
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247 |
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248 | pxdns->pcb4 = udp_new();
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249 | if (pxdns->pcb4 == NULL) {
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250 | error = ERR_MEM;
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251 | goto err_cleanup_pcb;
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252 | }
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253 |
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254 | pxdns->pcb6 = udp_new_ip6();
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255 | if (pxdns->pcb6 == NULL) {
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256 | error = ERR_MEM;
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257 | goto err_cleanup_pcb;
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258 | }
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259 |
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260 | error = udp_bind(pxdns->pcb4, IP_ADDR_ANY, 53);
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261 | if (error != ERR_OK) {
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262 | goto err_cleanup_pcb;
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263 | }
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264 |
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265 | error = udp_bind_ip6(pxdns->pcb6, IP6_ADDR_ANY, 53);
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266 | if (error != ERR_OK) {
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267 | goto err_cleanup_pcb;
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268 | }
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269 |
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270 | udp_recv(pxdns->pcb4, pxdns_recv4, pxdns);
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271 | udp_recv_ip6(pxdns->pcb6, pxdns_recv6, pxdns);
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272 |
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273 | pxdns->sock4 = socket(AF_INET, SOCK_DGRAM, 0);
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274 | if (pxdns->sock4 == INVALID_SOCKET) {
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275 | goto err_cleanup_pcb;
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276 | }
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277 |
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278 | pxdns->sock6 = socket(AF_INET6, SOCK_DGRAM, 0);
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279 | if (pxdns->sock6 == INVALID_SOCKET) {
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280 | /* it's ok if the host doesn't support IPv6 */
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281 | /* XXX: TODO: log */
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282 | }
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283 |
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284 | pxdns->generation = 0;
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285 | pxdns->nresolvers = 0;
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286 | pxdns->resolvers = NULL;
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287 | pxdns_create_resolver_sockaddrs(pxdns, g_proxy_options->nameservers);
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288 |
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289 | sys_mutex_new(&pxdns->lock);
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290 |
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291 | pxdns->timeout_slot = 0;
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292 | pxdns->timeout_mask = 0;
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293 |
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294 | /* NB: assumes pollmgr thread is not running yet */
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295 | pollmgr_add(&pxdns->pmhdl4, pxdns->sock4, POLLIN);
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296 | if (pxdns->sock6 != INVALID_SOCKET) {
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297 | pollmgr_add(&pxdns->pmhdl6, pxdns->sock6, POLLIN);
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298 | }
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299 |
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300 | return ERR_OK;
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301 |
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302 | err_cleanup_pcb:
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303 | if (pxdns->pcb4 != NULL) {
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304 | udp_remove(pxdns->pcb4);
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305 | pxdns->pcb4 = NULL;
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306 | }
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307 | if (pxdns->pcb6 != NULL) {
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308 | udp_remove(pxdns->pcb6);
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309 | pxdns->pcb4 = NULL;
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310 | }
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311 |
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312 | return error;
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313 | }
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314 |
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315 |
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316 | /**
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317 | * lwIP thread callback to set the new list of nameservers.
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318 | */
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319 | void
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320 | pxdns_set_nameservers(void *arg)
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321 | {
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322 | const char **nameservers = (const char **)arg;
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323 |
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324 | if (g_proxy_options->nameservers != NULL) {
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325 | RTMemFree((void *)g_proxy_options->nameservers);
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326 | }
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327 | g_proxy_options->nameservers = nameservers;
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328 |
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329 | pxdns_create_resolver_sockaddrs(&g_pxdns, nameservers);
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330 | }
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331 |
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332 |
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333 | /**
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334 | * Use this list of nameservers to resolve guest requests.
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335 | *
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336 | * Runs on lwIP thread, so no new queries or retramsmits compete with
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337 | * it for the use of the existing list of resolvers (to be replaced).
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338 | */
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339 | static void
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340 | pxdns_create_resolver_sockaddrs(struct pxdns *pxdns, const char **nameservers)
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341 | {
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342 | struct addrinfo hints;
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343 | union sockaddr_inet *resolvers;
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344 | size_t nnames, nresolvers;
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345 | const char **p;
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346 | int status;
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347 |
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348 | resolvers = NULL;
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349 | nresolvers = 0;
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350 |
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351 | if (nameservers == NULL) {
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352 | goto update_resolvers;
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353 | }
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354 |
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355 | nnames = 0;
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356 | for (p = nameservers; *p != NULL; ++p) {
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357 | ++nnames;
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358 | }
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359 |
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360 | if (nnames == 0) {
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361 | goto update_resolvers;
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362 | }
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363 |
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364 | resolvers = (union sockaddr_inet *)calloc(nnames, sizeof(resolvers[0]));
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365 | if (resolvers == NULL) {
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366 | nresolvers = 0;
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367 | goto update_resolvers;
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368 | }
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369 |
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370 | memset(&hints, 0, sizeof(hints));
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371 | hints.ai_family = AF_UNSPEC;
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372 | hints.ai_socktype = SOCK_DGRAM;
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373 | hints.ai_flags = AI_NUMERICHOST | AI_NUMERICSERV;
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374 |
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375 | for (p = nameservers; *p != NULL; ++p) {
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376 | const char *name = *p;
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377 | struct addrinfo *ai;
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378 | status = getaddrinfo(name, /* "domain" */ "53", &hints, &ai);
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379 | if (status != 0) {
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380 | /* XXX: log failed resolution */
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381 | continue;
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382 | }
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383 |
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384 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) {
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385 | /* XXX: log unsupported address family */
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386 | freeaddrinfo(ai);
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387 | continue;
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388 | }
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389 |
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390 | if (ai->ai_addrlen > sizeof(resolvers[nresolvers])) {
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391 | /* XXX: log */
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392 | freeaddrinfo(ai);
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393 | continue;
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394 | }
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395 |
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396 | if (ai->ai_family == AF_INET6 && pxdns->sock6 == INVALID_SOCKET) {
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397 | /* no IPv6 support on the host, can't use this resolver */
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398 | freeaddrinfo(ai);
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399 | continue;
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400 | }
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401 |
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402 | memcpy(&resolvers[nresolvers], ai->ai_addr, ai->ai_addrlen);
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403 | freeaddrinfo(ai);
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404 | ++nresolvers;
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405 | }
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406 |
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407 | if (nresolvers == 0) {
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408 | if (resolvers != NULL) {
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409 | free(resolvers);
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410 | }
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411 | resolvers = NULL;
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412 | }
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413 |
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414 | update_resolvers:
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415 | ++pxdns->generation;
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416 | if (pxdns->resolvers != NULL) {
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417 | free(pxdns->resolvers);
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418 | }
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419 | pxdns->resolvers = resolvers;
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420 | pxdns->nresolvers = nresolvers;
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421 | }
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422 |
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423 |
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424 | static void
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425 | pxdns_request_free(struct request *req)
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426 | {
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427 | LWIP_ASSERT1(req->pprev_hash == NULL);
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428 | LWIP_ASSERT1(req->pprev_timeout == NULL);
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429 |
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430 | if (req->reply != NULL) {
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431 | pbuf_free(req->reply);
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432 | }
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433 | free(req);
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434 | }
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435 |
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436 |
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437 | static void
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438 | pxdns_hash_add(struct pxdns *pxdns, struct request *req)
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439 | {
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440 | struct request **chain;
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441 |
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442 | LWIP_ASSERT1(req->pprev_hash == NULL);
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443 | ++pxdns->active_queries;
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444 |
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445 | chain = &pxdns->request_hash[HASH(req->id)];
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446 | if ((req->next_hash = *chain) != NULL) {
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447 | (*chain)->pprev_hash = &req->next_hash;
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448 | ++pxdns->hash_collisions;
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449 | }
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450 | *chain = req;
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451 | req->pprev_hash = chain;
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452 | }
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453 |
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454 |
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455 | static void
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456 | pxdns_timeout_add(struct pxdns *pxdns, struct request *req)
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457 | {
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458 | struct request **chain;
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459 | u32_t omask;
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460 |
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461 | LWIP_ASSERT1(req->pprev_timeout == NULL);
|
---|
462 |
|
---|
463 | req->timeout_slot = pxdns->timeout_slot;
|
---|
464 | chain = &pxdns->timeout_list[req->timeout_slot];
|
---|
465 | if ((req->next_timeout = *chain) != NULL) {
|
---|
466 | (*chain)->pprev_timeout = &req->next_timeout;
|
---|
467 | }
|
---|
468 | *chain = req;
|
---|
469 | req->pprev_timeout = chain;
|
---|
470 |
|
---|
471 | omask = pxdns->timeout_mask;
|
---|
472 | pxdns->timeout_mask |= 1U << req->timeout_slot;
|
---|
473 | if (omask == 0) {
|
---|
474 | sys_untimeout(pxdns_timer, pxdns);
|
---|
475 | sys_timeout(1 * 1000, pxdns_timer, pxdns);
|
---|
476 | }
|
---|
477 | }
|
---|
478 |
|
---|
479 |
|
---|
480 | static void
|
---|
481 | pxdns_hash_del(struct pxdns *pxdns, struct request *req)
|
---|
482 | {
|
---|
483 | LWIP_ASSERT1(req->pprev_hash != NULL);
|
---|
484 | --pxdns->active_queries;
|
---|
485 |
|
---|
486 | if (req->next_hash != NULL) {
|
---|
487 | req->next_hash->pprev_hash = req->pprev_hash;
|
---|
488 | }
|
---|
489 | *req->pprev_hash = req->next_hash;
|
---|
490 | req->pprev_hash = NULL;
|
---|
491 | req->next_hash = NULL;
|
---|
492 | }
|
---|
493 |
|
---|
494 |
|
---|
495 | static void
|
---|
496 | pxdns_timeout_del(struct pxdns *pxdns, struct request *req)
|
---|
497 | {
|
---|
498 | LWIP_ASSERT1(req->pprev_timeout != NULL);
|
---|
499 | LWIP_ASSERT1(req->timeout_slot < TIMEOUT);
|
---|
500 |
|
---|
501 | if (req->next_timeout != NULL) {
|
---|
502 | req->next_timeout->pprev_timeout = req->pprev_timeout;
|
---|
503 | }
|
---|
504 | *req->pprev_timeout = req->next_timeout;
|
---|
505 | req->pprev_timeout = NULL;
|
---|
506 | req->next_timeout = NULL;
|
---|
507 |
|
---|
508 | if (pxdns->timeout_list[req->timeout_slot] == NULL) {
|
---|
509 | pxdns->timeout_mask &= ~(1U << req->timeout_slot);
|
---|
510 | /* may be on pollmgr thread so no sys_untimeout */
|
---|
511 | }
|
---|
512 | }
|
---|
513 |
|
---|
514 |
|
---|
515 |
|
---|
516 | /**
|
---|
517 | * Do bookkeeping on new request. Called from pxdns_query().
|
---|
518 | */
|
---|
519 | static void
|
---|
520 | pxdns_request_register(struct pxdns *pxdns, struct request *req)
|
---|
521 | {
|
---|
522 | sys_mutex_lock(&pxdns->lock);
|
---|
523 |
|
---|
524 | pxdns_hash_add(pxdns, req);
|
---|
525 | pxdns_timeout_add(pxdns, req);
|
---|
526 |
|
---|
527 | sys_mutex_unlock(&pxdns->lock);
|
---|
528 | }
|
---|
529 |
|
---|
530 |
|
---|
531 | static void
|
---|
532 | pxdns_request_deregister(struct pxdns *pxdns, struct request *req)
|
---|
533 | {
|
---|
534 | sys_mutex_lock(&pxdns->lock);
|
---|
535 |
|
---|
536 | pxdns_hash_del(pxdns, req);
|
---|
537 | pxdns_timeout_del(pxdns, req);
|
---|
538 |
|
---|
539 | sys_mutex_unlock(&pxdns->lock);
|
---|
540 | }
|
---|
541 |
|
---|
542 |
|
---|
543 | /**
|
---|
544 | * Find request by the id we used when relaying it and remove it from
|
---|
545 | * id hash and timeout list. Called from pxdns_pmgr_pump() when reply
|
---|
546 | * comes.
|
---|
547 | */
|
---|
548 | static struct request *
|
---|
549 | pxdns_request_find(struct pxdns *pxdns, u16_t id)
|
---|
550 | {
|
---|
551 | struct request *req = NULL;
|
---|
552 |
|
---|
553 | sys_mutex_lock(&pxdns->lock);
|
---|
554 |
|
---|
555 | /* find request in the id->req hash */
|
---|
556 | for (req = pxdns->request_hash[HASH(id)]; req != NULL; req = req->next_hash) {
|
---|
557 | if (req->id == id) {
|
---|
558 | break;
|
---|
559 | }
|
---|
560 | }
|
---|
561 |
|
---|
562 | if (req != NULL) {
|
---|
563 | pxdns_hash_del(pxdns, req);
|
---|
564 | pxdns_timeout_del(pxdns, req);
|
---|
565 | }
|
---|
566 |
|
---|
567 | sys_mutex_unlock(&pxdns->lock);
|
---|
568 | return req;
|
---|
569 | }
|
---|
570 |
|
---|
571 |
|
---|
572 | /**
|
---|
573 | * Retransmit of g/c expired requests and move timeout slot forward.
|
---|
574 | */
|
---|
575 | static void
|
---|
576 | pxdns_timer(void *arg)
|
---|
577 | {
|
---|
578 | struct pxdns *pxdns = (struct pxdns *)arg;
|
---|
579 | struct request **chain, *req;
|
---|
580 | u32_t mask;
|
---|
581 |
|
---|
582 | sys_mutex_lock(&pxdns->lock);
|
---|
583 |
|
---|
584 | /*
|
---|
585 | * Move timeout slot first. New slot points to the list of
|
---|
586 | * expired requests. If any expired request is retransmitted, we
|
---|
587 | * keep it on the list (that is now current), effectively
|
---|
588 | * resetting the timeout.
|
---|
589 | */
|
---|
590 | LWIP_ASSERT1(pxdns->timeout_slot < TIMEOUT);
|
---|
591 | if (++pxdns->timeout_slot == TIMEOUT) {
|
---|
592 | pxdns->timeout_slot = 0;
|
---|
593 | }
|
---|
594 |
|
---|
595 | chain = &pxdns->timeout_list[pxdns->timeout_slot];
|
---|
596 | req = *chain;
|
---|
597 | while (req != NULL) {
|
---|
598 | struct request *expired = req;
|
---|
599 | req = req->next_timeout;
|
---|
600 |
|
---|
601 | if (pxdns_rexmit(pxdns, expired)) {
|
---|
602 | continue;
|
---|
603 | }
|
---|
604 |
|
---|
605 | pxdns_hash_del(pxdns, expired);
|
---|
606 | pxdns_timeout_del(pxdns, expired);
|
---|
607 | ++pxdns->expired_queries;
|
---|
608 |
|
---|
609 | pxdns_request_free(expired);
|
---|
610 | }
|
---|
611 |
|
---|
612 | if (pxdns->timeout_list[pxdns->timeout_slot] == NULL) {
|
---|
613 | pxdns->timeout_mask &= ~(1U << pxdns->timeout_slot);
|
---|
614 | }
|
---|
615 | else {
|
---|
616 | pxdns->timeout_mask |= 1U << pxdns->timeout_slot;
|
---|
617 | }
|
---|
618 | mask = pxdns->timeout_mask;
|
---|
619 |
|
---|
620 | sys_mutex_unlock(&pxdns->lock);
|
---|
621 |
|
---|
622 | if (mask != 0) {
|
---|
623 | sys_timeout(1 * 1000, pxdns_timer, pxdns);
|
---|
624 | }
|
---|
625 | }
|
---|
626 |
|
---|
627 |
|
---|
628 | static void
|
---|
629 | pxdns_recv4(void *arg, struct udp_pcb *pcb, struct pbuf *p,
|
---|
630 | ip_addr_t *addr, u16_t port)
|
---|
631 | {
|
---|
632 | struct pxdns *pxdns = (struct pxdns *)arg;
|
---|
633 | pxdns_query(pxdns, pcb, p, ip_2_ipX(addr), port);
|
---|
634 | }
|
---|
635 |
|
---|
636 | static void
|
---|
637 | pxdns_recv6(void *arg, struct udp_pcb *pcb, struct pbuf *p,
|
---|
638 | ip6_addr_t *addr, u16_t port)
|
---|
639 | {
|
---|
640 | struct pxdns *pxdns = (struct pxdns *)arg;
|
---|
641 | pxdns_query(pxdns, pcb, p, ip6_2_ipX(addr), port);
|
---|
642 | }
|
---|
643 |
|
---|
644 |
|
---|
645 | static void
|
---|
646 | pxdns_query(struct pxdns *pxdns, struct udp_pcb *pcb, struct pbuf *p,
|
---|
647 | ipX_addr_t *addr, u16_t port)
|
---|
648 | {
|
---|
649 | struct request *req;
|
---|
650 | int sent;
|
---|
651 |
|
---|
652 | if (pxdns->nresolvers == 0) {
|
---|
653 | /* nothing we can do */
|
---|
654 | pbuf_free(p);
|
---|
655 | return;
|
---|
656 | }
|
---|
657 |
|
---|
658 | req = calloc(1, sizeof(struct request) - 1 + p->tot_len);
|
---|
659 | if (req == NULL) {
|
---|
660 | pbuf_free(p);
|
---|
661 | return;
|
---|
662 | }
|
---|
663 |
|
---|
664 | /* copy request data */
|
---|
665 | req->size = p->tot_len;
|
---|
666 | pbuf_copy_partial(p, req->data, p->tot_len, 0);
|
---|
667 |
|
---|
668 | /* save client identity and client's request id */
|
---|
669 | req->pcb = pcb;
|
---|
670 | ipX_addr_copy(PCB_ISIPV6(pcb), req->client_addr, *addr);
|
---|
671 | req->client_port = port;
|
---|
672 | memcpy(&req->client_id, req->data, sizeof(req->client_id));
|
---|
673 |
|
---|
674 | /* slap our request id onto it */
|
---|
675 | req->id = pxdns->id++;
|
---|
676 | memcpy(req->data, &req->id, sizeof(u16_t));
|
---|
677 |
|
---|
678 | /* resolver to forward to */
|
---|
679 | req->generation = pxdns->generation;
|
---|
680 | req->residx = 0;
|
---|
681 |
|
---|
682 | /* prepare for relaying the reply back to guest */
|
---|
683 | req->msg_reply.type = TCPIP_MSG_CALLBACK_STATIC;
|
---|
684 | req->msg_reply.sem = NULL;
|
---|
685 | req->msg_reply.msg.cb.function = pxdns_pcb_reply;
|
---|
686 | req->msg_reply.msg.cb.ctx = (void *)req;
|
---|
687 |
|
---|
688 | DPRINTF2(("%s: req=%p: client id %d -> id %d\n",
|
---|
689 | __func__, (void *)req, req->client_id, req->id));
|
---|
690 |
|
---|
691 | pxdns_request_register(pxdns, req);
|
---|
692 |
|
---|
693 | sent = pxdns_forward_outbound(pxdns, req);
|
---|
694 | if (!sent) {
|
---|
695 | sent = pxdns_rexmit(pxdns, req);
|
---|
696 | }
|
---|
697 | if (!sent) {
|
---|
698 | pxdns_request_deregister(pxdns, req);
|
---|
699 | pxdns_request_free(req);
|
---|
700 | }
|
---|
701 | }
|
---|
702 |
|
---|
703 |
|
---|
704 | /**
|
---|
705 | * Forward request to the req::residx resolver in the pxdns::resolvers
|
---|
706 | * array of upstream resolvers.
|
---|
707 | *
|
---|
708 | * Returns 1 on success, 0 on failure.
|
---|
709 | */
|
---|
710 | static int
|
---|
711 | pxdns_forward_outbound(struct pxdns *pxdns, struct request *req)
|
---|
712 | {
|
---|
713 | union sockaddr_inet *resolver;
|
---|
714 | ssize_t nsent;
|
---|
715 | #ifdef RT_OS_WINDOWS
|
---|
716 | const char *pSendData = (const char *)&req->data[0];
|
---|
717 | int cbSendData = (int)req->size;
|
---|
718 | Assert((size_t)cbSendData == req->size);
|
---|
719 | #else
|
---|
720 | const void *pSendData = &req->data[0];
|
---|
721 | size_t cbSendData = req->size;
|
---|
722 | #endif
|
---|
723 |
|
---|
724 | DPRINTF2(("%s: req %p: sending to resolver #%lu\n",
|
---|
725 | __func__, (void *)req, (unsigned long)req->residx));
|
---|
726 |
|
---|
727 | LWIP_ASSERT1(req->generation == pxdns->generation);
|
---|
728 | LWIP_ASSERT1(req->residx < pxdns->nresolvers);
|
---|
729 | resolver = &pxdns->resolvers[req->residx];
|
---|
730 |
|
---|
731 | if (resolver->sa.sa_family == AF_INET) {
|
---|
732 | nsent = sendto(pxdns->sock4, pSendData, cbSendData, 0,
|
---|
733 | &resolver->sa, sizeof(resolver->sin));
|
---|
734 |
|
---|
735 | }
|
---|
736 | else if (resolver->sa.sa_family == AF_INET6) {
|
---|
737 | if (pxdns->sock6 != INVALID_SOCKET) {
|
---|
738 | nsent = sendto(pxdns->sock6, pSendData, cbSendData, 0,
|
---|
739 | &resolver->sa, sizeof(resolver->sin6));
|
---|
740 | }
|
---|
741 | else {
|
---|
742 | /* shouldn't happen, we should have weeded out IPv6 resolvers */
|
---|
743 | return 0;
|
---|
744 | }
|
---|
745 | }
|
---|
746 | else {
|
---|
747 | /* shouldn't happen, we should have weeded out unsupported families */
|
---|
748 | return 0;
|
---|
749 | }
|
---|
750 |
|
---|
751 | if ((size_t)nsent == req->size) {
|
---|
752 | return 1; /* sent */
|
---|
753 | }
|
---|
754 |
|
---|
755 | if (nsent < 0) {
|
---|
756 | DPRINTF2(("%s: send: %R[sockerr]\n", __func__, SOCKERRNO()));
|
---|
757 | }
|
---|
758 | else {
|
---|
759 | DPRINTF2(("%s: sent only %lu of %lu\n",
|
---|
760 | __func__, (unsigned long)nsent, (unsigned long)req->size));
|
---|
761 | }
|
---|
762 | return 0; /* not sent, caller will retry as necessary */
|
---|
763 | }
|
---|
764 |
|
---|
765 |
|
---|
766 | /**
|
---|
767 | * Forward request to the next resolver in the pxdns::resolvers array
|
---|
768 | * of upstream resolvers if there are any left.
|
---|
769 | */
|
---|
770 | static int
|
---|
771 | pxdns_rexmit(struct pxdns *pxdns, struct request *req)
|
---|
772 | {
|
---|
773 | int sent;
|
---|
774 |
|
---|
775 | if (/* __predict_false */ req->generation != pxdns->generation) {
|
---|
776 | DPRINTF2(("%s: req %p: generation %lu != pxdns generation %lu\n",
|
---|
777 | __func__, (void *)req,
|
---|
778 | (unsigned long)req->generation,
|
---|
779 | (unsigned long)pxdns->generation));
|
---|
780 | return 0;
|
---|
781 | }
|
---|
782 |
|
---|
783 | LWIP_ASSERT1(req->residx < pxdns->nresolvers);
|
---|
784 | do {
|
---|
785 | if (++req->residx == pxdns->nresolvers) {
|
---|
786 | return 0;
|
---|
787 | }
|
---|
788 |
|
---|
789 | sent = pxdns_forward_outbound(pxdns, req);
|
---|
790 | } while (!sent);
|
---|
791 |
|
---|
792 | return 1;
|
---|
793 | }
|
---|
794 |
|
---|
795 |
|
---|
796 | static int
|
---|
797 | pxdns_pmgr_pump(struct pollmgr_handler *handler, SOCKET fd, int revents)
|
---|
798 | {
|
---|
799 | struct pxdns *pxdns;
|
---|
800 | struct request *req;
|
---|
801 | ssize_t nread;
|
---|
802 | err_t error;
|
---|
803 | u16_t id;
|
---|
804 |
|
---|
805 | pxdns = (struct pxdns *)handler->data;
|
---|
806 | LWIP_ASSERT1(handler == &pxdns->pmhdl4 || handler == &pxdns->pmhdl6);
|
---|
807 | LWIP_ASSERT1(fd == (handler == &pxdns->pmhdl4 ? pxdns->sock4 : pxdns->sock6));
|
---|
808 |
|
---|
809 | if (revents & ~(POLLIN|POLLERR)) {
|
---|
810 | DPRINTF0(("%s: unexpected revents 0x%x\n", __func__, revents));
|
---|
811 | return POLLIN;
|
---|
812 | }
|
---|
813 |
|
---|
814 | if (revents & POLLERR) {
|
---|
815 | int sockerr = -1;
|
---|
816 | socklen_t optlen = (socklen_t)sizeof(sockerr);
|
---|
817 | int status;
|
---|
818 |
|
---|
819 | status = getsockopt(fd, SOL_SOCKET,
|
---|
820 | SO_ERROR, (char *)&sockerr, &optlen);
|
---|
821 | if (status < 0) {
|
---|
822 | DPRINTF(("%s: sock %d: SO_ERROR failed: %R[sockerr]\n",
|
---|
823 | __func__, fd, SOCKERRNO()));
|
---|
824 | }
|
---|
825 | else {
|
---|
826 | DPRINTF(("%s: sock %d: %R[sockerr]\n",
|
---|
827 | __func__, fd, sockerr));
|
---|
828 | }
|
---|
829 | }
|
---|
830 |
|
---|
831 | if ((revents & POLLIN) == 0) {
|
---|
832 | return POLLIN;
|
---|
833 | }
|
---|
834 |
|
---|
835 |
|
---|
836 | #ifdef RT_OS_WINDOWS
|
---|
837 | nread = recv(fd, (char *)pollmgr_udpbuf, sizeof(pollmgr_udpbuf), 0);
|
---|
838 | #else
|
---|
839 | nread = recv(fd, pollmgr_udpbuf, sizeof(pollmgr_udpbuf), 0);
|
---|
840 | #endif
|
---|
841 | if (nread < 0) {
|
---|
842 | DPRINTF(("%s: %R[sockerr]\n", __func__, SOCKERRNO()));
|
---|
843 | return POLLIN;
|
---|
844 | }
|
---|
845 |
|
---|
846 | /* check for minimum dns packet length */
|
---|
847 | if (nread < 12) {
|
---|
848 | DPRINTF2(("%s: short reply %lu bytes\n",
|
---|
849 | __func__, (unsigned long)nread));
|
---|
850 | return POLLIN;
|
---|
851 | }
|
---|
852 |
|
---|
853 | /* XXX: shall we proxy back RCODE=Refused responses? */
|
---|
854 |
|
---|
855 | memcpy(&id, pollmgr_udpbuf, sizeof(id));
|
---|
856 | req = pxdns_request_find(pxdns, id);
|
---|
857 | if (req == NULL) {
|
---|
858 | DPRINTF2(("%s: orphaned reply for %d\n", __func__, id));
|
---|
859 | ++pxdns->late_answers;
|
---|
860 | return POLLIN;
|
---|
861 | }
|
---|
862 |
|
---|
863 | DPRINTF2(("%s: reply for req=%p: id %d -> client id %d\n",
|
---|
864 | __func__, (void *)req, req->id, req->client_id));
|
---|
865 |
|
---|
866 | req->reply = pbuf_alloc(PBUF_RAW, nread, PBUF_RAM);
|
---|
867 | if (req->reply == NULL) {
|
---|
868 | DPRINTF(("%s: pbuf_alloc(%d) failed\n", __func__, (int)nread));
|
---|
869 | pxdns_request_free(req);
|
---|
870 | return POLLIN;
|
---|
871 | }
|
---|
872 |
|
---|
873 | memcpy(pollmgr_udpbuf, &req->client_id, sizeof(req->client_id));
|
---|
874 | error = pbuf_take(req->reply, pollmgr_udpbuf, nread);
|
---|
875 | if (error != ERR_OK) {
|
---|
876 | DPRINTF(("%s: pbuf_take(%d) failed\n", __func__, (int)nread));
|
---|
877 | pxdns_request_free(req);
|
---|
878 | return POLLIN;
|
---|
879 | }
|
---|
880 |
|
---|
881 | proxy_lwip_post(&req->msg_reply);
|
---|
882 | return POLLIN;
|
---|
883 | }
|
---|
884 |
|
---|
885 |
|
---|
886 | /**
|
---|
887 | * Called on lwIP thread via request::msg_reply callback.
|
---|
888 | */
|
---|
889 | static void
|
---|
890 | pxdns_pcb_reply(void *ctx)
|
---|
891 | {
|
---|
892 | struct request *req = (struct request *)ctx;
|
---|
893 | err_t error;
|
---|
894 |
|
---|
895 | error = udp_sendto(req->pcb, req->reply,
|
---|
896 | ipX_2_ip(&req->client_addr), req->client_port);
|
---|
897 | if (error != ERR_OK) {
|
---|
898 | DPRINTF(("%s: udp_sendto err %s\n",
|
---|
899 | __func__, proxy_lwip_strerr(error)));
|
---|
900 | }
|
---|
901 |
|
---|
902 | pxdns_request_free(req);
|
---|
903 | }
|
---|
904 |
|
---|
905 |
|
---|
906 | /**
|
---|
907 | * TCP DNS proxy. This kicks in for large replies that don't fit into
|
---|
908 | * 512 bytes of UDP payload. Client will retry with TCP to get
|
---|
909 | * complete reply.
|
---|
910 | */
|
---|
911 | static err_t
|
---|
912 | pxdns_accept_syn(void *arg, struct tcp_pcb *newpcb, struct pbuf *syn)
|
---|
913 | {
|
---|
914 | struct pxdns *pxdns = (struct pxdns *)arg;
|
---|
915 | union sockaddr_inet *si;
|
---|
916 | ipX_addr_t *dst;
|
---|
917 | u16_t dst_port;
|
---|
918 |
|
---|
919 | tcp_accepted(pxdns->ltcp);
|
---|
920 |
|
---|
921 | if (pxdns->nresolvers == 0) {
|
---|
922 | return ERR_CONN;
|
---|
923 | }
|
---|
924 |
|
---|
925 | si = &pxdns->resolvers[0];
|
---|
926 |
|
---|
927 | if (si->sa.sa_family == AF_INET6) {
|
---|
928 | dst = (ipX_addr_t *)&si->sin6.sin6_addr;
|
---|
929 | dst_port = ntohs(si->sin6.sin6_port);
|
---|
930 | }
|
---|
931 | else {
|
---|
932 | dst = (ipX_addr_t *)&si->sin.sin_addr;
|
---|
933 | dst_port = ntohs(si->sin.sin_port);
|
---|
934 | }
|
---|
935 |
|
---|
936 | /*
|
---|
937 | * XXX: TODO: need to implement protocol hooks. E.g. here if
|
---|
938 | * connect fails, we should try connecting to a different server.
|
---|
939 | */
|
---|
940 | return pxtcp_pcb_accept_outbound(newpcb, syn,
|
---|
941 | si->sa.sa_family == AF_INET6, dst, dst_port);
|
---|
942 | }
|
---|