tap.cc

来自「linux下基于c++的处理器仿真平台。具有处理器流水线」· CC 代码 · 共 544 行

/*
 * Copyright (c) 2003, 2004, 2005
 * The Regents of The University of Michigan
 * All Rights Reserved
 *
 * This code is part of the M5 simulator, developed by Nathan Binkert,
 * Erik Hallnor, Steve Raasch, and Steve Reinhardt, with contributions
 * from Ron Dreslinski, Dave Greene, Lisa Hsu, Kevin Lim, Ali Saidi,
 * and Andrew Schultz.
 *
 * Permission is granted to use, copy, create derivative works and
 * redistribute this software and such derivative works for any
 * purpose, so long as the copyright notice above, this grant of
 * permission, and the disclaimer below appear in all copies made; and
 * so long as the name of The University of Michigan is not used in
 * any advertising or publicity pertaining to the use or distribution
 * of this software without specific, written prior authorization.
 *
 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE
 * UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND
 * WITHOUT WARRANTY BY THE UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE
 * LIABLE FOR ANY DAMAGES, INCLUDING DIRECT, SPECIAL, INDIRECT,
 * INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGES.
 */

extern "C" {
#include <pcap.h>
}

#include <dnet.h>

#include <arpa/inet.h>

#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <netinet/tcp.h>

#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <netdb.h>
#include <poll.h>
#include <signal.h>
#include <unistd.h>

#include <list>
#include <string>

#include "base/cprintf.hh"

#define panic(arg...) \
  do { cprintf("Panic: " arg); exit(1); } while (0)

char *program = "ethertap";
void
usage()
{
    cprintf(
	"usage: \n"
	"\t%s [-b bufsize] [-d] [-f filter] [-p port] [-v] <device> <host>\n"
	"\t%s [-b bufsize] [-d] [-f filter] [-l] [-p port] [-v] <device>\n",
	program, program);
    exit(2);
}

int verbose = 0;
#define DPRINTF(args...) do { \
    if (verbose >= 1) \
        cprintf(args); \
} while (0)

#define DDUMP(args...) do { \
    if (verbose >= 2) \
        dump((const u_char *)args); \
} while (0)

void
dump(const u_char *data, int len)
{
	int c, i, j;

	for (i = 0; i < len; i += 16) {
		cprintf("%08x  ", i);
		c = len - i;
		if (c > 16) c = 16;

		for (j = 0; j < c; j++) {
			cprintf("%02x ", data[i + j] & 0xff);
			if ((j & 0xf) == 7 && j > 0)
				cprintf(" ");
		}

		for (; j < 16; j++)
			cprintf("   ");
		cprintf("  ");

		for (j = 0; j < c; j++) {
			int ch = data[i + j] & 0x7f;
			cprintf("%c", (char)(isprint(ch) ? ch : ' '));
		}

		cprintf("\n");

		if (c < 16)
			break;
	}
}

bool quit = false;
void
quit_now(int sigtype)
{
    DPRINTF("User requested exit\n");
    quit = true;
}


int
Socket(int reuse)
{
    int fd = ::socket(PF_INET, SOCK_STREAM, 0);
    if (fd < 0)
	panic("Can't create socket!\n");

    if (reuse) {
	int i = 1;
	if (::setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)&i,
			 sizeof(i)) < 0)
	    panic("setsockopt() SO_REUSEADDR failed!\n");
    }

    return fd;
}

void
Listen(int fd, int port)
{
    struct sockaddr_in sockaddr;
    sockaddr.sin_family = PF_INET;
    sockaddr.sin_addr.s_addr = INADDR_ANY;

    sockaddr.sin_port = htons(port);
    int ret = ::bind(fd, (struct sockaddr *)&sockaddr, sizeof (sockaddr));
    if (ret == -1)
	panic("bind() failed!\n");

    if (::listen(fd, 1) == -1)
	panic("listen() failed!\n");
}

// Open a connection.  Accept will block, so if you don't want it to,
// make sure a connection is ready before you call accept.
int
Accept(int fd, bool nodelay)
{
    struct sockaddr_in sockaddr;
    socklen_t slen = sizeof (sockaddr);
    int sfd = ::accept(fd, (struct sockaddr *)&sockaddr, &slen);
    if (sfd == -1)
	panic("accept() failed!\n");

    if (nodelay) {
	int i = 1;
	::setsockopt(sfd, IPPROTO_TCP, TCP_NODELAY, (char *)&i, sizeof(i));
    }
    return sfd;
}

void
Connect(int fd, const std::string &host, int port)
{
    struct sockaddr_in sockaddr;
    if (::inet_aton(host.c_str(), &sockaddr.sin_addr) == 0) {
	struct hostent *hp;
    	hp = ::gethostbyname(host.c_str());
	if (!hp)
	    panic("Host %s not found\n", host);

	sockaddr.sin_family = hp->h_addrtype;
	memcpy(&sockaddr.sin_addr, hp->h_addr, hp->h_length);
    }

    sockaddr.sin_port = htons(port);
    if (::connect(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr)) != 0)
	panic("could not connect to %s on port %d\n", host, port);

    DPRINTF("connected to %s on port %d\n", host, port);
}

class Ethernet
{
  protected:
    int fd;

  public:
    virtual ~Ethernet() {}

    int getfd() const { return fd; }
    virtual bool read(const char *&data, int &len) = 0;
    virtual bool write(const char *data, int len) = 0;
};

class Tap : public Ethernet
{
  private:
    char buffer[65536];
    int fd;

  public:
    Tap(char *device);
    ~Tap();
    virtual bool read(const char *&data, int &len);
    virtual bool write(const char *data, int len);
};

class PCap : public Ethernet
{
  private:
    pcap_t *pcap;
    eth_t *ethernet;

  public:
    PCap(char *device, char *filter = NULL);
    ~PCap();
    virtual bool read(const char *&data, int &len);
    virtual bool write(const char *data, int len);
};

PCap::PCap(char *device, char *filter)
{
    char errbuf[PCAP_ERRBUF_SIZE];
    memset(errbuf, 0, sizeof errbuf);
    pcap = pcap_open_live(device, 1500, 1, -1, errbuf);
    if (pcap == NULL)
	panic("pcap_open_live failed: %s\n", errbuf);

    if (filter) {
	bpf_program program;
	bpf_u_int32 localnet, netmask;
	if (pcap_lookupnet(device, &localnet, &netmask, errbuf) == -1) {
	    DPRINTF("pcap_lookupnet failed: %s\n", errbuf);
	    netmask = 0xffffff00;
	}

	if (pcap_compile(pcap, &program, filter, 1, netmask) == -1)
	    panic("pcap_compile failed, invalid filter:\n%s\n", filter);

	if (pcap_setfilter(pcap, &program) == -1)
	    panic("pcap_setfilter failed\n");
    }

    ethernet = eth_open(device);
    if (!ethernet)
	panic("cannot open the ethernet device for writing\n");

    fd = pcap_fileno(pcap);
}

PCap::~PCap()
{
    pcap_close(pcap);
    eth_close(ethernet);
}

bool
PCap::read(const char *&data, int &len)
{
    pcap_pkthdr hdr;
    data = (const char *)pcap_next(pcap, &hdr);
    if (!data)
	return false;

    len = hdr.len;
    return true;
}

bool
PCap::write(const char *data, int len)
{
    eth_send(ethernet, data, len);
}

Tap::Tap(char *device)
{
    fd = open(device, O_RDWR, 0);
    if (fd < 0)
	panic("could not open %s: %s\n", device, strerror(errno));
}

Tap::~Tap()
{
    close(fd);
}

bool
Tap::read(const char *&data, int &len)
{
    DPRINTF("tap read!\n");
    data = buffer;
    len = ::read(fd, buffer, sizeof(buffer));
    if (len < 0)
	return false;

    return true;
}

bool
Tap::write(const char *data, int len)
{
    int result = ::write(fd, data, len);
    if (result < 0)
	return false;

    return true;
}

int
main(int argc, char *argv[])
{
    int port = 3500;
    int bufsize = 2000;
    bool listening = false;
    char *device = NULL;
    char *filter = NULL;
    Ethernet *tap = NULL;
    bool usetap = false;
    char c;
    int daemon = false;
    std::string host;
    int devfd;

    program = basename(argv[0]);

    while ((c = getopt(argc, argv, "b:df:lp:tv")) != -1) {
	switch (c) {
	  case 'b':
	    bufsize = atoi(optarg);
	    break;
	  case 'd':
	    daemon = true;
	    break;
	  case 'f':
	    filter = optarg;
	    break;
	  case 'l':
	    listening = true;
	    break;
	  case 'p':
	    port = atoi(optarg);
	    break;
	  case 't':
	    usetap = true;
	    break;
	  case 'v':
	    verbose++;
	    break;
	  default:
	    usage();
	    break;
	}
    }

    signal(SIGINT, quit_now);
    signal(SIGTERM, quit_now);
    signal(SIGHUP, quit_now);

    if (daemon) {
	verbose = 0;
	switch(fork()) {
	  case -1:
	    panic("Fork failed\n");
	  case 0:
	    break;
	  default:
	    exit(0);
	}
    }

    char *buffer = new char[bufsize];
    argc -= optind;
    argv += optind;

    if (argc-- == 0)
	usage();

    device = *argv++;

    if (listening) {
	if (argc)
	    usage();
    } else {
	if (argc != 1)
	    usage();

	host = *argv;
    }
    
    if (usetap) {
	if (filter)
	    panic("-f parameter not valid with a tap device!");
	tap = new Tap(device);
    } else {
	tap = new PCap(device, filter);
    }

    pollfd pfds[3];
    pfds[0].fd = Socket(true);
    pfds[0].events = POLLIN;
    pfds[0].revents = 0;

    if (listening)
	Listen(pfds[0].fd, port);
    else
	Connect(pfds[0].fd, host, port);

    pfds[1].fd = tap->getfd();
    pfds[1].events = POLLIN;
    pfds[1].revents = 0;

    pfds[2].fd = 0;
    pfds[2].events = POLLIN|POLLERR;
    pfds[2].revents = 0;

    pollfd *listen_pfd = listening ? &pfds[0] : NULL;
    pollfd *tap_pfd = &pfds[1];
    pollfd *client_pfd = listening ? NULL : &pfds[0];
    int npfds = 2;

    int32_t buffer_offset = 0;
    int32_t data_len = 0;

    DPRINTF("Begin poll loop\n");
    while (!quit) {
	int ret = ::poll(pfds, npfds, INFTIM);
	if (ret < 0)
	    continue;

	if (listen_pfd && listen_pfd->revents) {
	    if (listen_pfd->revents & POLLIN) {
		int fd = Accept(listen_pfd->fd, false);
		if (client_pfd) {
		    DPRINTF("Connection rejected\n");
		    close(fd);
		} else {
		    DPRINTF("Connection accepted\n");
		    client_pfd = &pfds[2];
		    client_pfd->fd = fd;
		    npfds++;
		}
	    }
	    listen_pfd->revents = 0;
	}

	DPRINTF("tap events: %x\n", tap_pfd->revents);
	if (tap_pfd && tap_pfd->revents) {
	    if (tap_pfd->revents & POLLIN) {
		const char *data; int len;
		if (tap->read(data, len) && client_pfd) {
		    DPRINTF("Received packet from ethernet len=%d\n", len);
		    DDUMP(data, len);
		    u_int32_t swaplen = htonl(len);
		    write(client_pfd->fd, &swaplen, sizeof(swaplen));
		    write(client_pfd->fd, data, len);
		}
	    }

	    tap_pfd->revents = 0;
	}

	if (client_pfd && client_pfd->revents) {
	    if (client_pfd->revents & POLLIN) {
		if (buffer_offset < data_len + sizeof(u_int32_t)) {
		    int len = read(client_pfd->fd, buffer + buffer_offset,
				   bufsize - buffer_offset);

		    if (len <= 0) {
			perror("read");
			goto error;
		    }

		    buffer_offset += len;
		    if (data_len == 0)
			data_len = ntohl(*(u_int32_t *)buffer);

		    DPRINTF("Received data from peer: len=%d buffer_offset=%d "
			    "data_len=%d\n", len, buffer_offset, data_len);
		}

		while (data_len != 0 &&
		       buffer_offset >= data_len + sizeof(u_int32_t)) {
		    char *data = buffer + sizeof(u_int32_t);
		    tap->write(data, data_len);
		    DPRINTF("Sent packet to ethernet len = %d\n", data_len);
		    DDUMP(data, data_len);

		    buffer_offset -= data_len + sizeof(u_int32_t);
		    if (buffer_offset > 0 && data_len > 0) {
			memmove(buffer, data + data_len, buffer_offset);
			data_len = ntohl(*(u_int32_t *)buffer);
		    } else
			data_len = 0;
		}
	    }

	    if (client_pfd->revents & POLLERR) {
	      error:
		DPRINTF("Error on client socket\n");
		close(client_pfd->fd);
		client_pfd = NULL;

		if (listening)
		    npfds--;
		else {
		    DPRINTF("Calling it quits because of poll error\n");
		    quit = true;
		}
	    }

	    if (client_pfd)
		client_pfd->revents = 0;
	}
    }

    delete [] buffer;
    delete tap;

    if (listen_pfd)
	close(listen_pfd->fd);

    if (client_pfd)
	close(client_pfd->fd);

    return 0;
}