538 lines
13 KiB
C++
538 lines
13 KiB
C++
/*
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* Copyright (c) 2003-2005 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Nathan Binkert
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*/
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extern "C" {
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#include <pcap.h>
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}
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <netinet/tcp.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <dnet.h>
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#include <fcntl.h>
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#include <libgen.h>
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#include <netdb.h>
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#include <poll.h>
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#include <unistd.h>
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#include <cerrno>
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#include <csignal>
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#include <list>
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#include <string>
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#include "base/cprintf.hh"
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#define panic(arg...) \
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do { cprintf("Panic: " arg); exit(1); } while (0)
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char *program = "ethertap";
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void
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usage()
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{
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cprintf(
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"usage: \n"
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"\t%s [-b bufsize] [-d] [-f filter] [-p port] [-v] <device> <host>\n"
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"\t%s [-b bufsize] [-d] [-f filter] [-l] [-p port] [-v] <device>\n",
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program, program);
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exit(2);
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}
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int verbose = 0;
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#define DPRINTF(args...) do { \
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if (verbose >= 1) \
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cprintf(args); \
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} while (0)
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#define DDUMP(args...) do { \
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if (verbose >= 2) \
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dump((const u_char *)args); \
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} while (0)
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void
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dump(const u_char *data, int len)
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{
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int c, i, j;
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for (i = 0; i < len; i += 16) {
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cprintf("%08x ", i);
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c = len - i;
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if (c > 16) c = 16;
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for (j = 0; j < c; j++) {
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cprintf("%02x ", data[i + j] & 0xff);
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if ((j & 0xf) == 7 && j > 0)
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cprintf(" ");
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}
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for (; j < 16; j++)
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cprintf(" ");
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cprintf(" ");
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for (j = 0; j < c; j++) {
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int ch = data[i + j] & 0x7f;
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cprintf("%c", (char)(isprint(ch) ? ch : ' '));
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}
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cprintf("\n");
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if (c < 16)
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break;
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}
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}
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bool quit = false;
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void
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quit_now(int sigtype)
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{
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DPRINTF("User requested exit\n");
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quit = true;
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}
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int
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Socket(int reuse)
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{
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int fd = ::socket(PF_INET, SOCK_STREAM, 0);
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if (fd < 0)
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panic("Can't create socket!\n");
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if (reuse) {
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int i = 1;
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if (::setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)&i,
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sizeof(i)) < 0)
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panic("setsockopt() SO_REUSEADDR failed!\n");
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}
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return fd;
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}
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void
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Listen(int fd, int port)
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{
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struct sockaddr_in sockaddr;
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sockaddr.sin_family = PF_INET;
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sockaddr.sin_addr.s_addr = INADDR_ANY;
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sockaddr.sin_port = htons(port);
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int ret = ::bind(fd, (struct sockaddr *)&sockaddr, sizeof (sockaddr));
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if (ret == -1)
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panic("bind() failed!\n");
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if (::listen(fd, 1) == -1)
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panic("listen() failed!\n");
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}
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// Open a connection. Accept will block, so if you don't want it to,
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// make sure a connection is ready before you call accept.
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int
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Accept(int fd, bool nodelay)
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{
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struct sockaddr_in sockaddr;
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socklen_t slen = sizeof (sockaddr);
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int sfd = ::accept(fd, (struct sockaddr *)&sockaddr, &slen);
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if (sfd == -1)
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panic("accept() failed!\n");
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if (nodelay) {
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int i = 1;
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::setsockopt(sfd, IPPROTO_TCP, TCP_NODELAY, (char *)&i, sizeof(i));
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}
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return sfd;
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}
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void
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Connect(int fd, const std::string &host, int port)
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{
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struct sockaddr_in sockaddr;
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if (::inet_aton(host.c_str(), &sockaddr.sin_addr) == 0) {
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struct hostent *hp;
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hp = ::gethostbyname(host.c_str());
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if (!hp)
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panic("Host %s not found\n", host);
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sockaddr.sin_family = hp->h_addrtype;
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memcpy(&sockaddr.sin_addr, hp->h_addr, hp->h_length);
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}
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sockaddr.sin_port = htons(port);
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if (::connect(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr)) != 0)
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panic("could not connect to %s on port %d\n", host, port);
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DPRINTF("connected to %s on port %d\n", host, port);
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}
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class Ethernet
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{
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protected:
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int fd;
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public:
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virtual ~Ethernet() {}
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int getfd() const { return fd; }
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virtual bool read(const char *&data, int &len) = 0;
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virtual bool write(const char *data, int len) = 0;
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};
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class Tap : public Ethernet
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{
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private:
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char buffer[65536];
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int fd;
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public:
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Tap(char *device);
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~Tap();
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virtual bool read(const char *&data, int &len);
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virtual bool write(const char *data, int len);
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};
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class PCap : public Ethernet
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{
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private:
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pcap_t *pcap;
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eth_t *ethernet;
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public:
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PCap(char *device, char *filter = NULL);
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~PCap();
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virtual bool read(const char *&data, int &len);
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virtual bool write(const char *data, int len);
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};
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PCap::PCap(char *device, char *filter)
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{
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char errbuf[PCAP_ERRBUF_SIZE];
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memset(errbuf, 0, sizeof errbuf);
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pcap = pcap_open_live(device, 1500, 1, -1, errbuf);
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if (pcap == NULL)
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panic("pcap_open_live failed: %s\n", errbuf);
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if (filter) {
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bpf_program program;
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bpf_u_int32 localnet, netmask;
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if (pcap_lookupnet(device, &localnet, &netmask, errbuf) == -1) {
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DPRINTF("pcap_lookupnet failed: %s\n", errbuf);
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netmask = 0xffffff00;
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}
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if (pcap_compile(pcap, &program, filter, 1, netmask) == -1)
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panic("pcap_compile failed, invalid filter:\n%s\n", filter);
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if (pcap_setfilter(pcap, &program) == -1)
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panic("pcap_setfilter failed\n");
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}
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ethernet = eth_open(device);
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if (!ethernet)
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panic("cannot open the ethernet device for writing\n");
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fd = pcap_fileno(pcap);
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}
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PCap::~PCap()
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{
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pcap_close(pcap);
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eth_close(ethernet);
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}
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bool
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PCap::read(const char *&data, int &len)
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{
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pcap_pkthdr hdr;
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data = (const char *)pcap_next(pcap, &hdr);
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if (!data)
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return false;
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len = hdr.len;
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return true;
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}
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bool
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PCap::write(const char *data, int len)
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{
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eth_send(ethernet, data, len);
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}
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Tap::Tap(char *device)
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{
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fd = open(device, O_RDWR, 0);
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if (fd < 0)
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panic("could not open %s: %s\n", device, strerror(errno));
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}
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Tap::~Tap()
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{
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close(fd);
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}
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bool
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Tap::read(const char *&data, int &len)
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{
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DPRINTF("tap read!\n");
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data = buffer;
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len = ::read(fd, buffer, sizeof(buffer));
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if (len < 0)
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return false;
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return true;
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}
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bool
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Tap::write(const char *data, int len)
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{
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int result = ::write(fd, data, len);
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if (result < 0)
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return false;
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return true;
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}
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int
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main(int argc, char *argv[])
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{
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int port = 3500;
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int bufsize = 2000;
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bool listening = false;
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char *device = NULL;
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char *filter = NULL;
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Ethernet *tap = NULL;
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bool usetap = false;
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char c;
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int daemon = false;
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std::string host;
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int devfd;
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program = basename(argv[0]);
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while ((c = getopt(argc, argv, "b:df:lp:tv")) != -1) {
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switch (c) {
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case 'b':
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bufsize = atoi(optarg);
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break;
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case 'd':
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daemon = true;
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break;
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case 'f':
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filter = optarg;
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break;
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case 'l':
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listening = true;
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break;
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case 'p':
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port = atoi(optarg);
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break;
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case 't':
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usetap = true;
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break;
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case 'v':
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verbose++;
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break;
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default:
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usage();
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break;
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}
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}
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signal(SIGINT, quit_now);
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signal(SIGTERM, quit_now);
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signal(SIGHUP, quit_now);
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if (daemon) {
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verbose = 0;
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switch(fork()) {
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case -1:
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panic("Fork failed\n");
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case 0:
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break;
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default:
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exit(0);
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}
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}
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char *buffer = new char[bufsize];
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argc -= optind;
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argv += optind;
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if (argc-- == 0)
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usage();
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device = *argv++;
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if (listening) {
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if (argc)
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usage();
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} else {
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if (argc != 1)
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usage();
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host = *argv;
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}
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if (usetap) {
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if (filter)
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panic("-f parameter not valid with a tap device!");
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tap = new Tap(device);
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} else {
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tap = new PCap(device, filter);
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}
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pollfd pfds[3];
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pfds[0].fd = Socket(true);
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pfds[0].events = POLLIN;
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pfds[0].revents = 0;
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if (listening)
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Listen(pfds[0].fd, port);
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else
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Connect(pfds[0].fd, host, port);
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pfds[1].fd = tap->getfd();
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pfds[1].events = POLLIN;
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pfds[1].revents = 0;
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pfds[2].fd = 0;
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pfds[2].events = POLLIN|POLLERR;
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pfds[2].revents = 0;
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pollfd *listen_pfd = listening ? &pfds[0] : NULL;
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pollfd *tap_pfd = &pfds[1];
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pollfd *client_pfd = listening ? NULL : &pfds[0];
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int npfds = 2;
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int32_t buffer_offset = 0;
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int32_t data_len = 0;
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DPRINTF("Begin poll loop\n");
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while (!quit) {
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int ret = ::poll(pfds, npfds, INFTIM);
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if (ret < 0)
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continue;
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if (listen_pfd && listen_pfd->revents) {
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if (listen_pfd->revents & POLLIN) {
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int fd = Accept(listen_pfd->fd, false);
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if (client_pfd) {
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DPRINTF("Connection rejected\n");
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close(fd);
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} else {
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DPRINTF("Connection accepted\n");
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client_pfd = &pfds[2];
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client_pfd->fd = fd;
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npfds++;
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}
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}
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listen_pfd->revents = 0;
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}
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DPRINTF("tap events: %x\n", tap_pfd->revents);
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if (tap_pfd && tap_pfd->revents) {
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if (tap_pfd->revents & POLLIN) {
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const char *data; int len;
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if (tap->read(data, len) && client_pfd) {
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DPRINTF("Received packet from ethernet len=%d\n", len);
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DDUMP(data, len);
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u_int32_t swaplen = htonl(len);
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write(client_pfd->fd, &swaplen, sizeof(swaplen));
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write(client_pfd->fd, data, len);
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}
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}
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tap_pfd->revents = 0;
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}
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if (client_pfd && client_pfd->revents) {
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if (client_pfd->revents & POLLIN) {
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if (buffer_offset < data_len + sizeof(u_int32_t)) {
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int len = read(client_pfd->fd, buffer + buffer_offset,
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bufsize - buffer_offset);
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if (len <= 0) {
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perror("read");
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goto error;
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}
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buffer_offset += len;
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if (data_len == 0)
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data_len = ntohl(*(u_int32_t *)buffer);
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DPRINTF("Received data from peer: len=%d buffer_offset=%d "
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"data_len=%d\n", len, buffer_offset, data_len);
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}
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while (data_len != 0 &&
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buffer_offset >= data_len + sizeof(u_int32_t)) {
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char *data = buffer + sizeof(u_int32_t);
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tap->write(data, data_len);
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DPRINTF("Sent packet to ethernet len = %d\n", data_len);
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DDUMP(data, data_len);
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buffer_offset -= data_len + sizeof(u_int32_t);
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if (buffer_offset > 0 && data_len > 0) {
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memmove(buffer, data + data_len, buffer_offset);
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data_len = ntohl(*(u_int32_t *)buffer);
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} else
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data_len = 0;
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}
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}
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if (client_pfd->revents & POLLERR) {
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error:
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DPRINTF("Error on client socket\n");
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close(client_pfd->fd);
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client_pfd = NULL;
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if (listening)
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npfds--;
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else {
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DPRINTF("Calling it quits because of poll error\n");
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quit = true;
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}
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}
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if (client_pfd)
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client_pfd->revents = 0;
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}
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}
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delete [] buffer;
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delete tap;
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if (listen_pfd)
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close(listen_pfd->fd);
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if (client_pfd)
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close(client_pfd->fd);
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return 0;
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}
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