Search Site ~Sockets~  C++ Sockets   Tutorial   Classes   License   Java Sockets  ~Examples~  SMTPProxy   PortProxy   ChatServer   Small MUD   ClientServer   HttpGet   DChat   WebServer   UDP   ICMP  ~Contact~ message board  email author

ICMPTwistSocket.cpp Go to the documentation of this file. /* Copyright (C) 2004 Anders Hedstrom Parts Copyright (c) Vergil of Ragestorm.net, 2003 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include <ISocketHandler.h> #include <stdint.h> #include <linux/types.h> #include <linux/icmp.h> #include <errno.h> #include <Utility.h> #include "ICMPTwistSocket.h" ICMPTwistSocket::ICMPTwistSocket(ISocketHandler& h) : Socket(h) ,m_seq_no(0) { SOCKET s = CreateSocket(AF_INET, SOCK_RAW, "icmp"); if (s != INVALID_SOCKET) { // socket to filter out irrelevant ICMP, and make IO non-blocking static uint32_t flags = ~(1 << ICMP_INFO_REQUEST); if (setsockopt(s, SOL_RAW, ICMP_FILTER, &flags, sizeof(uint32_t)) == -1) { Handler().LogError(this, "setsockopt", errno, strerror(errno)); } Attach(s); Set(true, false, false); } memset(&m_info, 0, sizeof(m_info)); m_info.type = ICMP_INFO_REQUEST; } ICMPTwistSocket::~ICMPTwistSocket() { } void ICMPTwistSocket::OnRead() { int len; int hsize; uint8_t incoming[1000]; if (recv(GetSocket(), m_info.buffer, 4, MSG_PEEK) != -1) { len = ntohs(*(uint16_t *)(m_info.buffer + 2)); if (len < 1000) { if (recv(GetSocket(), incoming, len, 0) == -1) { Handler().LogError(this, "recv", errno, strerror(errno), LOG_LEVEL_WARNING); } else { // IP Header length + ICMP header length hsize = (m_info.buffer[0] & 0xf) << 2; uint16_t crc; memcpy(&crc, incoming + hsize + 2, 2); if (calc_crc(incoming + hsize, len - hsize) != crc) //*(uint16_t *)(incoming + hsize + 2)) { printf("(Bad crc)\n"); } else { printf("Received: %s\n", incoming + hsize + 8); } } } } } void ICMPTwistSocket::Connect(const std::string& host) { struct sockaddr_in dest; ipaddr_t a; if (Utility::u2ip(host, a)) { memset(&dest, 0, sizeof(dest)); dest.sin_port = htons(IPPROTO_ICMP); dest.sin_family = AF_INET; memcpy(&dest.sin_addr, &a, 4); if (connect(GetSocket(), (struct sockaddr *)&dest, sizeof(struct sockaddr)) == -1) { Handler().LogError(this, "Connect", errno, strerror(errno), LOG_LEVEL_FATAL); SetCloseAndDelete(); } } else { printf("u2ip failed\n"); } } void ICMPTwistSocket::Send(const std::string& line) { strcpy(m_info.buffer, line.c_str()); int len = line.size() + 9; m_info.checksum = calc_crc((uint8_t *)&m_info, len); int n; if ((n = send(GetSocket(), (void *)&m_info, len, 0)) == -1) { Handler().LogError(this, "Send", errno, strerror(errno)); } m_info.seq_no = htons(m_seq_no++); } uint16_t ICMPTwistSocket::calc_crc(uint8_t * packet, size_t len) { uint16_t r; uint16_t i; uint32_t s; s = (packet[0] << 8) + packet[1]; for (i = 4; i < len - 1; i += 2) { s += (packet[i] << 8) + packet[i + 1]; } if (len % 2) // an extra member { s += packet[len - 1] << 8; } s = (s & 0xffff) + (s >> 16); r = s + (s >> 16); return htons(~r); }

Page, code, and content Copyright (C) 2006 by Anders Hedström

---