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| 1 | +#ifndef LINUX_MULTICAST_TRANSPORT_H |
| 2 | +#define LINUX_MULTICAST_TRANSPORT_H |
| 3 | + |
| 4 | +#include "delegate/DelegateOpt.h" |
| 5 | +#include "predef/transport/ITransport.h" |
| 6 | +#include "predef/transport/DmqHeader.h" |
| 7 | + |
| 8 | +#include <iostream> |
| 9 | +#include <sstream> |
| 10 | +#include <cstring> |
| 11 | +#include <cstdlib> |
| 12 | +#include <unistd.h> |
| 13 | +#include <arpa/inet.h> |
| 14 | +#include <sys/socket.h> |
| 15 | +#include <net/if.h> |
| 16 | +#include <fcntl.h> |
| 17 | +#include <errno.h> |
| 18 | + |
| 19 | +/// @brief Linux Multicast UDP transport implementation for DelegateMQ. |
| 20 | +class MulticastTransport : public ITransport |
| 21 | +{ |
| 22 | +public: |
| 23 | + enum class Type { PUB, SUB }; |
| 24 | + |
| 25 | + MulticastTransport() = default; |
| 26 | + ~MulticastTransport() { Close(); } |
| 27 | + |
| 28 | + int Create(Type type, const char* groupAddr, uint16_t port, const char* localInterface = "0.0.0.0") |
| 29 | + { |
| 30 | + m_type = type; |
| 31 | + m_socket = socket(AF_INET, SOCK_DGRAM, 0); |
| 32 | + if (m_socket < 0) return -1; |
| 33 | + |
| 34 | + int reuse = 1; |
| 35 | + setsockopt(m_socket, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)); |
| 36 | + |
| 37 | + // ALWAYS enable loopback for testing convenience |
| 38 | + int loop = 1; |
| 39 | + setsockopt(m_socket, IPPROTO_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop)); |
| 40 | + |
| 41 | + memset(&m_addr, 0, sizeof(m_addr)); |
| 42 | + m_addr.sin_family = AF_INET; |
| 43 | + m_addr.sin_port = htons(port); |
| 44 | + |
| 45 | + if (type == Type::PUB) { |
| 46 | + m_addr.sin_addr.s_addr = inet_addr(groupAddr); |
| 47 | + |
| 48 | + struct in_addr interface_addr; |
| 49 | + interface_addr.s_addr = inet_addr(localInterface); |
| 50 | + setsockopt(m_socket, IPPROTO_IP, IP_MULTICAST_IF, &interface_addr, sizeof(interface_addr)); |
| 51 | + |
| 52 | + int ttl = 3; |
| 53 | + setsockopt(m_socket, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); |
| 54 | + } |
| 55 | + else { |
| 56 | + m_addr.sin_addr.s_addr = INADDR_ANY; |
| 57 | + if (bind(m_socket, (struct sockaddr*)&m_addr, sizeof(m_addr)) < 0) return -1; |
| 58 | + |
| 59 | + struct ip_mreq mreq; |
| 60 | + mreq.imr_multiaddr.s_addr = inet_addr(groupAddr); |
| 61 | + mreq.imr_interface.s_addr = inet_addr(localInterface); |
| 62 | + if (setsockopt(m_socket, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) { |
| 63 | + return -1; |
| 64 | + } |
| 65 | + |
| 66 | + struct timeval timeout; |
| 67 | + timeout.tv_sec = 1; |
| 68 | + timeout.tv_usec = 0; |
| 69 | + setsockopt(m_socket, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)); |
| 70 | + } |
| 71 | + return 0; |
| 72 | + } |
| 73 | + |
| 74 | + void Close() { |
| 75 | + if (m_socket != -1) { |
| 76 | + close(m_socket); |
| 77 | + m_socket = -1; |
| 78 | + } |
| 79 | + } |
| 80 | + |
| 81 | + virtual int Send(xostringstream& os, const DmqHeader& header) override { |
| 82 | + if (m_type != Type::PUB) return -1; |
| 83 | + std::string payload = os.str(); |
| 84 | + DmqHeader headerCopy = header; |
| 85 | + headerCopy.SetLength(static_cast<uint16_t>(payload.length())); |
| 86 | + |
| 87 | + xostringstream ss(std::ios::in | std::ios::out | std::ios::binary); |
| 88 | + uint16_t marker = htons(headerCopy.GetMarker()); |
| 89 | + uint16_t id = htons(headerCopy.GetId()); |
| 90 | + uint16_t seqNum = htons(headerCopy.GetSeqNum()); |
| 91 | + uint16_t length = htons(headerCopy.GetLength()); |
| 92 | + |
| 93 | + ss.write((const char*)&marker, 2); |
| 94 | + ss.write((const char*)&id, 2); |
| 95 | + ss.write((const char*)&seqNum, 2); |
| 96 | + ss.write((const char*)&length, 2); |
| 97 | + ss.write(payload.data(), payload.size()); |
| 98 | + |
| 99 | + std::string data = ss.str(); |
| 100 | + sendto(m_socket, data.c_str(), data.size(), 0, (struct sockaddr*)&m_addr, sizeof(m_addr)); |
| 101 | + return 0; |
| 102 | + } |
| 103 | + |
| 104 | + virtual int Receive(xstringstream& is, DmqHeader& header) override { |
| 105 | + if (m_type != Type::SUB) return -1; |
| 106 | + int size = recvfrom(m_socket, m_buffer, sizeof(m_buffer), 0, NULL, NULL); |
| 107 | + |
| 108 | + if (size <= (int)DmqHeader::HEADER_SIZE) return -1; |
| 109 | + |
| 110 | + xstringstream headerStream(std::ios::in | std::ios::out | std::ios::binary); |
| 111 | + headerStream.write(m_buffer, DmqHeader::HEADER_SIZE); |
| 112 | + headerStream.seekg(0); |
| 113 | + |
| 114 | + uint16_t val = 0; |
| 115 | + headerStream.read((char*)&val, 2); header.SetMarker(ntohs(val)); |
| 116 | + headerStream.read((char*)&val, 2); header.SetId(ntohs(val)); |
| 117 | + headerStream.read((char*)&val, 2); header.SetSeqNum(ntohs(val)); |
| 118 | + headerStream.read((char*)&val, 2); header.SetLength(ntohs(val)); |
| 119 | + |
| 120 | + if (header.GetMarker() != DmqHeader::MARKER) { |
| 121 | + // std::cerr << "[Multicast] Bad Marker: " << std::hex << header.GetMarker() << std::dec << std::endl; |
| 122 | + return -1; |
| 123 | + } |
| 124 | + |
| 125 | + is.write(m_buffer + DmqHeader::HEADER_SIZE, size - DmqHeader::HEADER_SIZE); |
| 126 | + return 0; |
| 127 | + } |
| 128 | + |
| 129 | +private: |
| 130 | + int m_socket = -1; |
| 131 | + sockaddr_in m_addr{}; |
| 132 | + Type m_type = Type::PUB; |
| 133 | + static const int BUFFER_SIZE = 4096; |
| 134 | + char m_buffer[BUFFER_SIZE] = { 0 }; |
| 135 | +}; |
| 136 | + |
| 137 | +#endif |
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