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Add an LLMNR responder implementation #2880
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,281 @@ | ||
| /* | ||
| * ESP8266 LLMNR responder | ||
| * Copyright (C) 2017 Stephen Warren <[email protected]> | ||
| * | ||
| * Based on: | ||
| * ESP8266 Multicast DNS (port of CC3000 Multicast DNS library) | ||
| * Version 1.1 | ||
| * Copyright (c) 2013 Tony DiCola ([email protected]) | ||
| * ESP8266 port (c) 2015 Ivan Grokhotkov ([email protected]) | ||
| * MDNS-SD Suport 2015 Hristo Gochkov | ||
| * Extended MDNS-SD support 2016 Lars Englund ([email protected]) | ||
| * | ||
| * License (MIT license): | ||
| * | ||
| * Permission is hereby granted, free of charge, to any person obtaining a copy | ||
| * of this software and associated documentation files (the "Software"), to deal | ||
| * in the Software without restriction, including without limitation the rights | ||
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | ||
| * copies of the Software, and to permit persons to whom the Software is | ||
| * furnished to do so, subject to the following conditions: | ||
| * | ||
| * The above copyright notice and this permission notice shall be included in | ||
| * all copies or substantial portions of the Software. | ||
| * | ||
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | ||
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | ||
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | ||
| * THE SOFTWARE. | ||
| * | ||
| * Reference: | ||
| * https://tools.ietf.org/html/rfc4795 (LLMNR) | ||
| * https://tools.ietf.org/html/rfc1035 (DNS) | ||
| */ | ||
|
|
||
| #include <debug.h> | ||
| #include <functional> | ||
| #include <ESP8266LLMNR.h> | ||
| #include <WiFiUdp.h> | ||
|
|
||
| extern "C" { | ||
| #include <user_interface.h> | ||
| } | ||
|
|
||
| #include <lwip/udp.h> | ||
| #include <lwip/igmp.h> | ||
| #include <include/UdpContext.h> | ||
|
|
||
| //#define LLMNR_DEBUG | ||
|
|
||
| #define BIT(x) (1 << (x)) | ||
|
|
||
| #define FLAGS_QR BIT(15) | ||
| #define FLAGS_OP_SHIFT 11 | ||
| #define FLAGS_OP_MASK 0xf | ||
| #define FLAGS_C BIT(10) | ||
| #define FLAGS_TC BIT(9) | ||
| #define FLAGS_T BIT(8) | ||
| #define FLAGS_RCODE_SHIFT 0 | ||
| #define FLAGS_RCODE_MASK 0xf | ||
|
|
||
| #define _conn_read16() (((uint16_t)_conn->read() << 8) | _conn->read()) | ||
| #define _conn_read8() _conn->read() | ||
| #define _conn_readS(b, l) _conn->read((b), (l)); | ||
|
|
||
| static const IPAddress LLMNR_MULTICAST_ADDR(224, 0, 0, 252); | ||
| static const int LLMNR_MULTICAST_TTL = 1; | ||
| static const int LLMNR_PORT = 5355; | ||
|
|
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| LLMNRResponder::LLMNRResponder() : | ||
| _conn(0) { | ||
| } | ||
|
|
||
| LLMNRResponder::~LLMNRResponder() { | ||
| if (_conn) | ||
| _conn->unref(); | ||
| } | ||
|
|
||
| bool LLMNRResponder::begin(const char* hostname) { | ||
| // Max length for a single label in DNS | ||
| if (strlen(hostname) > 63) | ||
| return false; | ||
|
|
||
| _hostname = hostname; | ||
| _hostname.toLowerCase(); | ||
|
|
||
| _sta_got_ip_handler = WiFi.onStationModeGotIP([this](const WiFiEventStationModeGotIP& event){ | ||
| _restart(); | ||
| }); | ||
|
|
||
| _sta_disconnected_handler = WiFi.onStationModeDisconnected([this](const WiFiEventStationModeDisconnected& event) { | ||
| _restart(); | ||
| }); | ||
|
|
||
| return _restart(); | ||
| } | ||
|
|
||
| void LLMNRResponder::notify_ap_change() { | ||
| _restart(); | ||
| } | ||
|
|
||
| bool LLMNRResponder::_restart() { | ||
| if (_conn) { | ||
| _conn->unref(); | ||
| _conn = 0; | ||
| } | ||
|
|
||
| ip_addr_t multicast_addr; | ||
| multicast_addr.addr = (uint32_t)LLMNR_MULTICAST_ADDR; | ||
|
|
||
| if (igmp_joingroup(IP_ADDR_ANY, &multicast_addr) != ERR_OK) | ||
| return false; | ||
|
|
||
| _conn = new UdpContext; | ||
| _conn->ref(); | ||
|
|
||
| if (!_conn->listen(*IP_ADDR_ANY, LLMNR_PORT)) | ||
| return false; | ||
|
|
||
| _conn->setMulticastTTL(LLMNR_MULTICAST_TTL); | ||
| _conn->onRx(std::bind(&LLMNRResponder::_process_packet, this)); | ||
| _conn->connect(multicast_addr, LLMNR_PORT); | ||
| } | ||
|
|
||
| void LLMNRResponder::_process_packet() { | ||
| if (!_conn || !_conn->next()) | ||
| return; | ||
|
|
||
| #ifdef LLMNR_DEBUG | ||
| Serial.println("LLMNR: RX'd packet"); | ||
| #endif | ||
|
|
||
| uint16_t id = _conn_read16(); | ||
| uint16_t flags = _conn_read16(); | ||
| uint16_t qdcount = _conn_read16(); | ||
| uint16_t ancount = _conn_read16(); | ||
| uint16_t nscount = _conn_read16(); | ||
| uint16_t arcount = _conn_read16(); | ||
|
|
||
| #ifdef LLMNR_DEBUG | ||
| Serial.print("LLMNR: ID="); | ||
| Serial.println(id, HEX); | ||
| Serial.print("LLMNR: FLAGS="); | ||
| Serial.println(flags, HEX); | ||
| Serial.print("LLMNR: QDCOUNT="); | ||
| Serial.println(qdcount); | ||
| Serial.print("LLMNR: ANCOUNT="); | ||
| Serial.println(ancount); | ||
| Serial.print("LLMNR: NSCOUNT="); | ||
| Serial.println(nscount); | ||
| Serial.print("LLMNR: ARCOUNT="); | ||
| Serial.println(arcount); | ||
| #endif | ||
|
|
||
| #define BAD_FLAGS (FLAGS_QR | (FLAGS_OP_MASK << FLAGS_OP_SHIFT) | FLAGS_C) | ||
| if (flags & BAD_FLAGS) { | ||
| #ifdef LLMNR_DEBUG | ||
| Serial.println("Bad flags"); | ||
| #endif | ||
| return; | ||
| } | ||
|
|
||
| if (qdcount != 1) { | ||
| #ifdef LLMNR_DEBUG | ||
| Serial.println("QDCOUNT != 1"); | ||
| #endif | ||
| return; | ||
| } | ||
|
|
||
| if (ancount || nscount || arcount) { | ||
| #ifdef LLMNR_DEBUG | ||
| Serial.println("AN/NS/AR-COUNT != 0"); | ||
| #endif | ||
| return; | ||
| } | ||
|
|
||
| uint8_t namelen = _conn_read8(); | ||
| #ifdef LLMNR_DEBUG | ||
| Serial.print("QNAME len "); | ||
| Serial.println(namelen); | ||
| #endif | ||
| if (namelen != _hostname.length()) { | ||
| #ifdef LLMNR_DEBUG | ||
| Serial.println("QNAME len mismatch"); | ||
| #endif | ||
| return; | ||
| } | ||
|
|
||
| char qname[64]; | ||
| _conn_readS(qname, namelen); | ||
| _conn_read8(); | ||
| qname[namelen] = '\0'; | ||
| #ifdef LLMNR_DEBUG | ||
| Serial.print("QNAME "); | ||
| Serial.println(qname); | ||
| #endif | ||
|
|
||
| if (strcmp(_hostname.c_str(), qname)) { | ||
| #ifdef LLMNR_DEBUG | ||
| Serial.println("QNAME mismatch"); | ||
| #endif | ||
| return; | ||
| } | ||
|
|
||
| uint16_t qtype = _conn_read16(); | ||
| uint16_t qclass = _conn_read16(); | ||
|
|
||
| #ifdef LLMNR_DEBUG | ||
| Serial.print("QTYPE "); | ||
| Serial.print(qtype); | ||
| Serial.print(" QCLASS "); | ||
| Serial.println(qclass); | ||
| #endif | ||
|
|
||
| bool have_rr = | ||
| (qtype == 1) && /* A */ | ||
| (qclass == 1); /* IN */ | ||
|
|
||
| _conn->flush(); | ||
|
|
||
| #ifdef LLMNR_DEBUG | ||
| Serial.println("Match; responding"); | ||
| if (!have_rr) | ||
| Serial.println("(no matching RRs)"); | ||
| #endif | ||
|
|
||
| struct ip_info remote_ip_info; | ||
| remote_ip_info.ip.addr = _conn->getRemoteAddress(); | ||
| struct ip_info ip_info; | ||
| bool match_ap = false; | ||
| if (wifi_get_opmode() & SOFTAP_MODE) { | ||
| wifi_get_ip_info(SOFTAP_IF, &ip_info); | ||
| if (ip_info.ip.addr && ip_addr_netcmp(&remote_ip_info.ip, &ip_info.ip, &ip_info.netmask)) | ||
| match_ap = true; | ||
| } | ||
| if (!match_ap) | ||
| wifi_get_ip_info(STATION_IF, &ip_info); | ||
| uint32_t ip = ip_info.ip.addr; | ||
|
|
||
| // Header | ||
| uint8_t header[] = { | ||
| id >> 8, id & 0xff, // ID | ||
| FLAGS_QR >> 8, 0, // FLAGS | ||
| 0, 1, // QDCOUNT | ||
| 0, !!have_rr, // ANCOUNT | ||
| 0, 0, // NSCOUNT | ||
| 0, 0, // ARCOUNT | ||
| }; | ||
| _conn->append(reinterpret_cast<const char*>(header), sizeof(header)); | ||
| // Question | ||
| _conn->append(reinterpret_cast<const char*>(&namelen), 1); | ||
| _conn->append(qname, namelen); | ||
| uint8_t q[] = { | ||
| 0, // Name terminator | ||
| 0, 1, // TYPE (A) | ||
| 0, 1, // CLASS (IN) | ||
| }; | ||
| _conn->append(reinterpret_cast<const char*>(q), sizeof(q)); | ||
| // Answer, if we have one | ||
| if (have_rr) { | ||
| _conn->append(reinterpret_cast<const char*>(&namelen), 1); | ||
| _conn->append(qname, namelen); | ||
| uint8_t rr[] = { | ||
| 0, // Name terminator | ||
| 0, 1, // TYPE (A) | ||
| 0, 1, // CLASS (IN) | ||
| 0, 0, 0, 30, // TTL (30 seconds) | ||
| 0, 4, // RDLENGTH | ||
| ip & 0xff, (ip >> 8) & 0xff, (ip >> 16) & 0xff, (ip >> 24) & 0xff, // RDATA | ||
| }; | ||
| _conn->append(reinterpret_cast<const char*>(rr), sizeof(rr)); | ||
| } | ||
| _conn->setMulticastInterface(remote_ip_info.ip); | ||
| _conn->send(&remote_ip_info.ip, _conn->getRemotePort()); | ||
| } | ||
|
|
||
| #if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_LLMNR) | ||
| LLMNRResponder LLMNR; | ||
| #endif | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,66 @@ | ||
| /* | ||
| * ESP8266 LLMNR responder | ||
| * Copyright (C) 2017 Stephen Warren <[email protected]> | ||
| * | ||
| * Based on: | ||
| * ESP8266 Multicast DNS (port of CC3000 Multicast DNS library) | ||
| * Version 1.1 | ||
| * Copyright (c) 2013 Tony DiCola ([email protected]) | ||
| * ESP8266 port (c) 2015 Ivan Grokhotkov ([email protected]) | ||
| * MDNS-SD Suport 2015 Hristo Gochkov | ||
| * Extended MDNS-SD support 2016 Lars Englund ([email protected]) | ||
| * | ||
| * License (MIT license): | ||
| * | ||
| * Permission is hereby granted, free of charge, to any person obtaining a copy | ||
| * of this software and associated documentation files (the "Software"), to deal | ||
| * in the Software without restriction, including without limitation the rights | ||
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | ||
| * copies of the Software, and to permit persons to whom the Software is | ||
| * furnished to do so, subject to the following conditions: | ||
| * | ||
| * The above copyright notice and this permission notice shall be included in | ||
| * all copies or substantial portions of the Software. | ||
| * | ||
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | ||
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | ||
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | ||
| * THE SOFTWARE. | ||
| */ | ||
|
|
||
| #ifndef ESP8266LLMNR_H | ||
| #define ESP8266LLMNR_H | ||
|
|
||
| #include <ESP8266WiFi.h> | ||
|
|
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| class UdpContext; | ||
|
|
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| class LLMNRResponder { | ||
| public: | ||
| LLMNRResponder(); | ||
| ~LLMNRResponder(); | ||
|
|
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| /* Initialize and start responding to LLMNR requests on all interfaces */ | ||
| bool begin(const char* hostname); | ||
|
|
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| /* Application should call this whenever AP is configured/disabled */ | ||
| void notify_ap_change(); | ||
|
|
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| private: | ||
| String _hostname; | ||
| UdpContext *_conn; | ||
| WiFiEventHandler _sta_got_ip_handler; | ||
| WiFiEventHandler _sta_disconnected_handler; | ||
|
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| bool _restart(); | ||
| void _process_packet(); | ||
| }; | ||
|
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| #if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_LLMNR) | ||
| extern LLMNRResponder LLMNR; | ||
| #endif | ||
|
|
||
| #endif |
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It's a minor thing, but in some other places you put braces around one-line if bodies. Suggest doing the same thing everywhere.