Rune Harlyk
145 lines
4.0 KiB
C++
145 lines
4.0 KiB
C++
#pragma once
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#include <lwip/sockets.h>
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#include <lwip/netdb.h>
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#include <esp_log.h>
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#include <utils/ip_address.h>
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#include <freertos/FreeRTOS.h>
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#include <freertos/task.h>
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#include <string>
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#include <atomic>
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#define DNS_PORT 53
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#define DNS_MAX_PACKET_SIZE 512
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class DNSServer {
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public:
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DNSServer() : _socket(-1), _running(false), _task(nullptr) {}
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~DNSServer() { stop(); }
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bool start(uint16_t port, const char* domainName, const IPAddress& resolvedIP) {
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if (_running) return true;
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_port = port;
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_resolvedIP = resolvedIP;
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_domainName = domainName ? domainName : "*";
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_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
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if (_socket < 0) {
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ESP_LOGE("DNSServer", "Failed to create socket");
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return false;
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}
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int opt = 1;
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setsockopt(_socket, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
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struct timeval tv;
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tv.tv_sec = 1;
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tv.tv_usec = 0;
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setsockopt(_socket, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
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struct sockaddr_in serverAddr = {};
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serverAddr.sin_family = AF_INET;
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serverAddr.sin_addr.s_addr = INADDR_ANY;
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serverAddr.sin_port = htons(_port);
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if (bind(_socket, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) < 0) {
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ESP_LOGE("DNSServer", "Failed to bind socket");
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close(_socket);
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_socket = -1;
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return false;
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}
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_running = true;
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xTaskCreate(dnsTask, "dns_server", 4096, this, 3, &_task);
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ESP_LOGI("DNSServer", "Started on port %d, resolving to %s", _port, _resolvedIP.toString().c_str());
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return true;
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}
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void stop() {
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_running = false;
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if (_task) {
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vTaskDelay(100 / portTICK_PERIOD_MS);
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_task = nullptr;
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}
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if (_socket >= 0) {
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close(_socket);
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_socket = -1;
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}
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ESP_LOGI("DNSServer", "Stopped");
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}
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void processNextRequest() {}
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private:
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static void dnsTask(void* param) {
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DNSServer* self = static_cast<DNSServer*>(param);
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self->run();
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vTaskDelete(nullptr);
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}
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void run() {
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uint8_t buffer[DNS_MAX_PACKET_SIZE];
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struct sockaddr_in clientAddr;
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socklen_t clientAddrLen = sizeof(clientAddr);
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while (_running) {
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int len = recvfrom(_socket, buffer, DNS_MAX_PACKET_SIZE, 0, (struct sockaddr*)&clientAddr, &clientAddrLen);
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if (len > 0) {
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processRequest(buffer, len, &clientAddr);
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}
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}
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}
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void processRequest(uint8_t* buffer, int len, struct sockaddr_in* clientAddr) {
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if (len < 12) return;
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uint16_t flags = (buffer[2] << 8) | buffer[3];
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if ((flags & 0x8000) != 0) return;
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uint8_t response[DNS_MAX_PACKET_SIZE];
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memcpy(response, buffer, len);
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response[2] = 0x81;
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response[3] = 0x80;
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response[6] = 0x00;
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response[7] = 0x01;
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int responseLen = len;
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response[responseLen++] = 0xC0;
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response[responseLen++] = 0x0C;
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response[responseLen++] = 0x00;
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response[responseLen++] = 0x01;
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response[responseLen++] = 0x00;
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response[responseLen++] = 0x01;
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response[responseLen++] = 0x00;
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response[responseLen++] = 0x00;
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response[responseLen++] = 0x00;
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response[responseLen++] = 0x3C;
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response[responseLen++] = 0x00;
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response[responseLen++] = 0x04;
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uint32_t ip = static_cast<uint32_t>(_resolvedIP);
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response[responseLen++] = ip & 0xFF;
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response[responseLen++] = (ip >> 8) & 0xFF;
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response[responseLen++] = (ip >> 16) & 0xFF;
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response[responseLen++] = (ip >> 24) & 0xFF;
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sendto(_socket, response, responseLen, 0, (struct sockaddr*)clientAddr, sizeof(*clientAddr));
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}
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int _socket;
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uint16_t _port;
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IPAddress _resolvedIP;
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std::string _domainName;
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std::atomic<bool> _running;
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TaskHandle_t _task;
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};
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