--- a/src/devices/tap-bridge/tap-sock-creator.cc Tue Jan 27 12:36:46 2009 -0800
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,456 +0,0 @@
-/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/*
- * Copyright (c) 2009 University of Washington
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation;
- *
- * 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 <unistd.h>
-#include <stdint.h>
-#include <string>
-#include <iostream>
-#include <iomanip>
-#include <sstream>
-#include <stdlib.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <sys/ioctl.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <linux/un.h>
-#include <linux/if.h>
-#include <linux/if_tun.h>
-#include <linux/route.h>
-#include <netinet/in.h>
-
-#include "tap-encode-decode.h"
-
-#define TAP_MAGIC 95549
-
-static int gVerbose = 0;
-
-#define LOG(msg) \
- if (gVerbose) \
- { \
- std::cout << __FUNCTION__ << "(): " << msg << std::endl; \
- }
-
-#define ABORT(msg, printErrno) \
- std::cout << __FILE__ << ": fatal error at line " << __LINE__ << ": " << __FUNCTION__ << "(): " << msg << std::endl; \
- if (printErrno) \
- { \
- std::cout << " errno = " << errno << " (" << strerror (errno) << ")" << std::endl; \
- } \
- exit (-1);
-
-#define ABORT_IF(cond, msg, printErrno) \
- if (cond) \
- { \
- ABORT(msg, printErrno); \
- }
-
-//
-// Thanks, Mathieu, for the beginning of these functions
-//
-#define ASCII_DOT (0x2e)
-#define ASCII_ZERO (0x30)
-#define ASCII_a (0x41)
-#define ASCII_z (0x5a)
-#define ASCII_A (0x61)
-#define ASCII_Z (0x7a)
-#define ASCII_COLON (0x3a)
-#define ASCII_ZERO (0x30)
-
-static char
-AsciiToLowCase (char c)
-{
- if (c >= ASCII_a && c <= ASCII_z) {
- return c;
- } else if (c >= ASCII_A && c <= ASCII_Z) {
- return c + (ASCII_a - ASCII_A);
- } else {
- return c;
- }
-}
-
-static uint32_t
-AsciiToIpv4 (const char *address)
-{
- uint32_t host = 0;
- while (true) {
- uint8_t byte = 0;
- while (*address != ASCII_DOT &&
- *address != 0) {
- byte *= 10;
- byte += *address - ASCII_ZERO;
- address++;
- }
- host <<= 8;
- host |= byte;
- if (*address == 0) {
- break;
- }
- address++;
- }
- return host;
-}
-
-static void
-AsciiToMac48 (const char *str, uint8_t addr[6])
-{
- int i = 0;
- while (*str != 0 && i < 6)
- {
- uint8_t byte = 0;
- while (*str != ASCII_COLON && *str != 0)
- {
- byte <<= 4;
- char low = AsciiToLowCase (*str);
- if (low >= ASCII_a)
- {
- byte |= low - ASCII_a + 10;
- }
- else
- {
- byte |= low - ASCII_ZERO;
- }
- str++;
- }
- addr[i] = byte;
- i++;
- if (*str == 0)
- {
- break;
- }
- str++;
- }
-}
-
-static void
-SetInetAddress (sockaddr *ad, uint32_t networkOrder)
-{
- struct sockaddr_in *sin = (struct sockaddr_in*)ad;
- sin->sin_family = AF_INET;
- sin->sin_port = 0; // unused
- sin->sin_addr.s_addr = htonl (networkOrder);
-}
-
-/**
- * \brief Send the socket file descriptor we created back to the tap bridge,
- * which will read it as soon as we're done.
- *
- * \param path The socket address information from the Unix socket we use
- * to send the created socket back to.
- * \param fd The socket we're going to send.
- */
- static void
-SendSocket (const char *path, int fd)
-{
- //
- // Open a Unix (local interprocess) socket to call back to the tap bridge
- //
- LOG ("Create Unix socket");
- int sock = socket (PF_UNIX, SOCK_DGRAM, 0);
- ABORT_IF (sock == -1, "Unable to open socket", 1);
-
- //
- // We have this string called path, which is really a hex representation
- // of the endpoint that the tap bridge created. It used a forward encoding
- // method (TapBufferToString) to take the sockaddr_un it made and passed
- // the resulting string to us. So we need to take the inverse method
- // (TapStringToBuffer) and build the same sockaddr_un over here.
- //
- socklen_t clientAddrLen;
- struct sockaddr_un clientAddr;
-
- LOG ("Decode address " << path);
- bool rc = ns3::TapStringToBuffer (path, (uint8_t *)&clientAddr, &clientAddrLen);
- ABORT_IF (rc == false, "Unable to decode path", 0);
-
- LOG ("Connect");
- int status = connect (sock, (struct sockaddr*)&clientAddr, clientAddrLen);
- ABORT_IF (status == -1, "Unable to connect to tap bridge", 1);
-
- LOG ("Connected");
-
- //
- // This is arcane enough that a few words are worthwhile to explain what's
- // going on here.
- //
- // The interesting information (the socket FD) is going to go back to the
- // tap bridge as an integer of ancillary data. Ancillary data is bits
- // that are not a part a socket payload (out-of-band data). We're also
- // going to send one integer back. It's just initialized to a magic number
- // we use to make sure that the tap bridge is talking to the tap socket
- // creator and not some other creator process (emu, specifically)
- //
- // The struct iovec below is part of a scatter-gather list. It describes a
- // buffer. In this case, it describes a buffer (an integer) containing the
- // data that we're going to send back to the tap bridge (that magic number).
- //
- struct iovec iov;
- uint32_t magic = TAP_MAGIC;
- iov.iov_base = &magic;
- iov.iov_len = sizeof(magic);
-
- //
- // The CMSG macros you'll see below are used to create and access control
- // messages (which is another name for ancillary data). The ancillary
- // data is made up of pairs of struct cmsghdr structures and associated
- // data arrays.
- //
- // First, we're going to allocate a buffer on the stack to contain our
- // data array (that contains the socket). Sometimes you'll see this called
- // an "ancillary element" but the msghdr uses the control message termimology
- // so we call it "control."
- //
- size_t msg_size = sizeof(int);
- char control[CMSG_SPACE(msg_size)];
-
- //
- // There is a msghdr that is used to minimize the number of parameters
- // passed to sendmsg (which we will use to send our ancillary data). This
- // structure uses terminology corresponding to control messages, so you'll
- // see msg_control, which is the pointer to the ancillary data and controllen
- // which is the size of the ancillary data array.
- //
- // So, initialize the message header that describes our ancillary/control data
- // and point it to the control message/ancillary data we just allocated space
- // for.
- //
- struct msghdr msg;
- msg.msg_name = 0;
- msg.msg_namelen = 0;
- msg.msg_iov = &iov;
- msg.msg_iovlen = 1;
- msg.msg_control = control;
- msg.msg_controllen = sizeof (control);
- msg.msg_flags = 0;
-
- //
- // A cmsghdr contains a length field that is the length of the header and
- // the data. It has a cmsg_level field corresponding to the originating
- // protocol. This takes values which are legal levels for getsockopt and
- // setsockopt (here SOL_SOCKET). We're going to use the SCM_RIGHTS type of
- // cmsg, that indicates that the ancillary data array contains access rights
- // that we are sending back to the tap bridge.
- //
- // We have to put together the first (and only) cmsghdr that will describe
- // the whole package we're sending.
- //
- struct cmsghdr *cmsg;
- cmsg = CMSG_FIRSTHDR(&msg);
- cmsg->cmsg_level = SOL_SOCKET;
- cmsg->cmsg_type = SCM_RIGHTS;
- cmsg->cmsg_len = CMSG_LEN(msg_size);
- //
- // We also have to update the controllen in case other stuff is actually
- // in there we may not be aware of (due to macros).
- //
- msg.msg_controllen = cmsg->cmsg_len;
-
- //
- // Finally, we get a pointer to the start of the ancillary data array and
- // put our file descriptor in.
- //
- int *fdptr = (int*) (CMSG_DATA(cmsg));
- *fdptr = fd; //
-
- //
- // Actually send the file descriptor back to the tap bridge.
- //
- ssize_t len = sendmsg(sock, &msg, 0);
- ABORT_IF (len == -1, "Could not send socket back to tap bridge", 1);
-
- LOG ("sendmsg complete");
-}
-
- static int
-CreateTap (const char *dev, const char *gw, const char *ip, const char *netmask, const char *mac)
-{
- //
- // Creation and management of Tap devices is done via the tun device
- //
- int tap = open ("/dev/net/tun", O_RDWR);
- ABORT_IF (tap == -1, "Could not open /dev/net/tun", true);
-
- //
- // Allocate a tap device, making sure that it will not send the tun_pi header.
- // If we provide a null name to the ifr.ifr_name, we tell the kernel to pick
- // a name for us (i.e., tapn where n = 0..255
- //
- struct ifreq ifr;
- ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
- strcpy (ifr.ifr_name, dev);
- int status = ioctl (tap, TUNSETIFF, (void *) &ifr);
- ABORT_IF (status == -1, "Could not allocate tap device", true);
-
- std::string tapDeviceName = (char *)ifr.ifr_name;
- LOG ("Allocated TAP device " << tapDeviceName);
-
- //
- // Set the hardware (MAC) address of the new device
- //
- ifr.ifr_hwaddr.sa_family = 1; // this is ARPHRD_ETHER from if_arp.h
- AsciiToMac48 (mac, (uint8_t*)ifr.ifr_hwaddr.sa_data);
- status = ioctl (tap, SIOCSIFHWADDR, &ifr);
- ABORT_IF (status == -1, "Could not set MAC address", true);
- LOG ("Set device MAC address to " << mac);
-
- int fd = socket (AF_INET, SOCK_DGRAM, 0);
-
- //
- // Bring the interface up.
- //
- status = ioctl (fd, SIOCGIFFLAGS, &ifr);
- ABORT_IF (status == -1, "Could not get flags for interface", true);
- ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
- status = ioctl (fd, SIOCSIFFLAGS, &ifr);
- ABORT_IF (status == -1, "Could not bring interface up", true);
- LOG ("Device is up");
-
- //
- // Set the IP address of the new interface/device.
- //
- SetInetAddress (&ifr.ifr_addr, AsciiToIpv4 (ip));
- status = ioctl (fd, SIOCSIFADDR, &ifr);
- ABORT_IF (status == -1, "Could not set IP address", true);
- LOG ("Set device IP address to " << ip);
-
- //
- // Set the net mask of the new interface/device
- //
- SetInetAddress (&ifr.ifr_netmask, AsciiToIpv4 (netmask));
- status = ioctl (fd, SIOCSIFNETMASK, &ifr);
- ABORT_IF (status == -1, "Could not set net mask", true);
- LOG ("Set device Net Mask to " << netmask);
-
- return tap;
-}
-
- int
-main (int argc, char *argv[])
-{
- int c;
- char *dev = NULL;
- char *gw = NULL;
- char *ip = NULL;
- char *mac = NULL;
- char *netmask = NULL;
- char *path = NULL;
-
- opterr = 0;
-
- while ((c = getopt (argc, argv, "vd:g:i:m:n:p:")) != -1)
- {
- switch (c)
- {
- case 'v':
- gVerbose = true;
- break;
- case 'd':
- dev = optarg; // name of the new tap device
- break;
- case 'g':
- gw = optarg; // gateway address for the new device
- break;
- case 'i':
- ip = optarg; // ip address of the new device
- break;
- case 'm':
- mac = optarg; // mac address of the new device
- break;
- case 'n':
- netmask = optarg; // net mask for the new device
- break;
- case 'p':
- path = optarg; // path back to the tap bridge
- break;
- }
- }
-
- //
- // We have got to be able to coordinate the name of the tap device we are
- // going to create and or open with the device that an external Linux host
- // will use. THis name is given in dev
- //
- ABORT_IF (dev == NULL, "Device Name is a required argument", 0);
- LOG ("Provided Device Name is \"" << dev << "\"");
-
- //
- // We have got to be able to provide a gateway to the external Linux host
- // so it can talk to the ns-3 network. This ip address is provided in
- // gw.
- //
- ABORT_IF (gw == NULL, "Gateway Address is a required argument", 0);
- LOG ("Provided Gateway Address is \"" << dev << "\"");
-
- //
- // We have got to be able to assign an IP address to the tap device we are
- // allocating. This address is allocated in the simulation and assigned to
- // the tap bridge. This address is given in ip.
- //
- ABORT_IF (ip == NULL, "IP Address is a required argument", 0);
- LOG ("Provided IP Address is \"" << ip << "\"");
-
- //
- // We have got to be able to assign a Mac address to the tap device we are
- // allocating. This address is allocated in the simulation and assigned to
- // the bridged device. This allows packets addressed to the bridged device
- // to appear in the Linux host as if they were received there.
- //
- ABORT_IF (mac == NULL, "MAC Address is a required argument", 0);
- LOG ("Provided MAC Address is \"" << mac << "\"");
-
- //
- // We have got to be able to assign a net mask to the tap device we are
- // allocating. This mask is allocated in the simulation and given to
- // the bridged device.
- //
- ABORT_IF (netmask == NULL, "Net Mask is a required argument", 0);
- LOG ("Provided Net Mask is \"" << netmask << "\"");
-
- //
- // This program is spawned by a tap bridge running in a simulation. It
- // wants to create a socket as described below. We are going to do the
- // work here since we're running suid root. Once we create the socket,
- // we have to send it back to the tap bridge. We do that over a Unix
- // (local interprocess) socket. The tap bridge created a socket to
- // listen for our response on, and it is expected to have encoded the address
- // information as a string and to have passed that string as an argument to
- // us. We see it here as the "path" string. We can't do anything useful
- // unless we have that string.
- //
- ABORT_IF (path == NULL, "path is a required argument", 0);
- LOG ("Provided path is \"" << path << "\"");
-
- //
- // The whole reason for all of the hoops we went through to call out to this
- // program will pay off here. We created this program to run as suid root
- // in order to keep the main simulation program from having to be run with
- // root privileges. We need root privileges to be able to futz with the
- // Tap device underlying all of this. So all of these hoops are to allow
- // us to exeucte the following code:
- //
- LOG ("Creating Tap");
- int sock = CreateTap (dev, gw, ip, mac, netmask);
- ABORT_IF (sock == -1, "main(): Unable to create tap socket", 1);
-
- //
- // Send the socket back to the tap net device so it can go about its business
- //
- SendSocket (path, sock);
-
- return 0;
-}