236 lines
6.3 KiB
C++
236 lines
6.3 KiB
C++
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Library General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* InterfacePicker.cpp
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* Chooses an interface to listen on
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* Copyright (C) 2005-2010 Simon Newton
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*/
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#if HAVE_CONFIG_H
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# include <config.h>
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#endif
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#ifdef HAVE_GETIFADDRS
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#ifdef HAVE_LINUX_IF_PACKET_H
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#define OLA_USE_GETIFADDRS
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#endif
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#endif
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#ifdef OLA_USE_GETIFADDRS
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#include <ifaddrs.h>
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#include <linux/types.h>
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#include <linux/if_packet.h>
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#endif
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#include <arpa/inet.h>
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#include <errno.h>
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#include <net/if.h>
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#ifdef HAVE_SOCKADDR_DL_STRUCT
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#include <net/if_dl.h>
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#endif
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#include <string.h>
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#include <sys/ioctl.h>
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#include <algorithm>
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#include <string>
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#include <vector>
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#include "common/network/PosixInterfacePicker.h"
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#include "ola/Logging.h"
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#include "ola/network/NetworkUtils.h"
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namespace ola {
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namespace network {
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using std::string;
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using std::vector;
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/*
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* Return a vector of interfaces on the system.
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*/
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vector<Interface> PosixInterfacePicker::GetInterfaces() const {
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vector<Interface> interfaces;
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string last_dl_iface_name;
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uint8_t hwlen = 0;
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char *hwaddr = NULL;
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// create socket to get iface config
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int sd = socket(PF_INET, SOCK_DGRAM, 0);
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if (sd < 0) {
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OLA_WARN << "Could not create socket " << strerror(errno);
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return interfaces;
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}
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// use ioctl to get a listing of interfaces
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char *buffer; // holds the iface data
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unsigned int lastlen = 0; // the amount of data returned by the last ioctl
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unsigned int len = INITIAL_IFACE_COUNT;
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while (true) {
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struct ifconf ifc;
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ifc.ifc_len = len * sizeof(struct ifreq);
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buffer = new char[ifc.ifc_len];
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ifc.ifc_buf = buffer;
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if (ioctl(sd, SIOCGIFCONF, &ifc) < 0) {
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if (errno != EINVAL || lastlen != 0) {
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OLA_WARN << "ioctl error " << strerror(errno);
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delete[] buffer;
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return interfaces;
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}
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} else {
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if (static_cast<unsigned int>(ifc.ifc_len) == lastlen) {
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lastlen = ifc.ifc_len;
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break;
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}
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lastlen = ifc.ifc_len;
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}
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len += IFACE_COUNT_INC;
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delete[] buffer;
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}
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// loop through each iface
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for (char *ptr = buffer; ptr < buffer + lastlen;) {
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struct ifreq *iface = (struct ifreq*) ptr;
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ptr += GetIfReqSize(ptr);
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#ifdef HAVE_SOCKADDR_DL_STRUCT
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if (iface->ifr_addr.sa_family == AF_LINK) {
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struct sockaddr_dl *sdl = (struct sockaddr_dl*) &iface->ifr_addr;
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last_dl_iface_name.assign(sdl->sdl_data, sdl->sdl_nlen);
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hwaddr = sdl->sdl_data + sdl->sdl_nlen;
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hwlen = sdl->sdl_alen;
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}
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#endif
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// look for AF_INET interfaces only
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if (iface->ifr_addr.sa_family != AF_INET) {
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OLA_DEBUG << "skipping " << iface->ifr_name <<
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" because it's not af_inet";
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continue;
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}
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struct ifreq ifrcopy = *iface;
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if (ioctl(sd, SIOCGIFFLAGS, &ifrcopy) < 0) {
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OLA_WARN << "ioctl error for " << iface->ifr_name << ":"
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<< strerror(errno);
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continue;
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}
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if (!(ifrcopy.ifr_flags & IFF_UP)) {
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OLA_DEBUG << "skipping " << iface->ifr_name << " because it's down";
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continue;
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}
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if (ifrcopy.ifr_flags & IFF_LOOPBACK) {
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OLA_DEBUG << "skipping " << iface->ifr_name <<
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" because it's a loopback";
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continue;
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}
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Interface interface;
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interface.name = iface->ifr_name;
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if (interface.name == last_dl_iface_name && hwaddr) {
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memcpy(interface.hw_address, hwaddr,
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std::min(hwlen, (uint8_t) MAC_LENGTH));
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}
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struct sockaddr_in *sin = (struct sockaddr_in *) &iface->ifr_addr;
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interface.ip_address = sin->sin_addr;
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// fetch bcast address
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#ifdef SIOCGIFBRDADDR
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if (ifrcopy.ifr_flags & IFF_BROADCAST) {
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if (ioctl(sd, SIOCGIFBRDADDR, &ifrcopy) < 0) {
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OLA_WARN << "ioctl error " << strerror(errno);
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} else {
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sin = (struct sockaddr_in *) &ifrcopy.ifr_broadaddr;
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interface.bcast_address = sin->sin_addr;
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}
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}
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#endif
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// fetch subnet address
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#ifdef SIOCGIFNETMASK
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if (ioctl(sd, SIOCGIFNETMASK, &ifrcopy) < 0) {
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OLA_WARN << "ioctl error " << strerror(errno);
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} else {
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sin = (struct sockaddr_in *) &ifrcopy.ifr_broadaddr;
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interface.subnet_address = sin->sin_addr;
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}
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#endif
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// fetch hardware address
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#ifdef SIOCGIFHWADDR
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if (ifrcopy.ifr_flags & SIOCGIFHWADDR) {
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if (ioctl(sd, SIOCGIFHWADDR, &ifrcopy) < 0) {
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OLA_WARN << "ioctl error" << strerror(errno);
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} else {
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memcpy(interface.hw_address, ifrcopy.ifr_hwaddr.sa_data, MAC_LENGTH);
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}
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}
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#endif
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/* ok, if that all failed we should prob try and use sysctl to work out the bcast
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* and hware addresses
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* i'll leave that for another day
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*/
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interfaces.push_back(interface);
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}
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close(sd);
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delete[] buffer;
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return interfaces;
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}
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/*
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* Return the size of an ifreq structure in a cross platform manner.
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* @param data a pointer to an ifreq structure
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* @return the size of the ifreq structure
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*/
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unsigned int PosixInterfacePicker::GetIfReqSize(const char *data) const {
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const struct ifreq *iface = (struct ifreq*) data;
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#ifdef HAVE_SOCKADDR_SA_LEN
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unsigned int socket_len = iface->ifr_addr.sa_len;
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#else
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unsigned int socket_len = sizeof(struct sockaddr);
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switch (iface->ifr_addr.sa_family) {
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case AF_INET:
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socket_len = sizeof(struct sockaddr_in);
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break;
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#ifdef IPV6
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case AF_INET6:
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socket_len = sizeof(struct sockaddr_in6);
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break;
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#endif
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#ifdef HAVE_SOCKADDR_DL_STRUCT
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case AF_LINK:
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socket_len = sizeof(struct sockaddr_dl);
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break;
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#endif
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}
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#endif
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// We can't assume sizeof(ifreq) = IFNAMSIZ + sizeof(sockaddr), this isn't
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// the case on some 64bit linux systems.
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if (socket_len > sizeof(struct ifreq) - IFNAMSIZ)
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return IFNAMSIZ + socket_len;
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else
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return sizeof(struct ifreq);
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}
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} // network
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} // ola
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