[1237] Initial interface detection implemented for Linux.

- Interface detection implemented for Linux.
- OS-specific defines added to configure.ac
- Added stub interface detection for BSD systems.

configure.ac

@@ -367,6 +367,33 @@ AC_HEADER_STDBOOL
 AC_TYPE_SIZE_T
 
 
+# Detect OS type (it may be used to do OS-specific things, e.g.
+# interface detection in DHCP)
+AC_MSG_CHECKING(OS family)
+system=`uname -s`
+case $system in
+    Linux)
+      OS_TYPE="LINUX"
+      CPPFLAGS="$CPPFLAGS -DOS_LINUX"
+      ;;
+    Darwin | FreeBSD | NetBSD | OpenBSD)
+      OS_TYPE="BSD"
+      CPPFLAGS="$CPPFLAGS -DOS_BSD"
+      ;;
+    Solaris)
+      OS_TYPE="Solaris"
+      CPPFLAGS="$CPPFLAGS -DOS_SOLARIS"
+      ;;
+    *)
+      OS_TYPE="Unknown"
+      AC_MSG_WARN("Unsupported OS: uname returned $system")
+      ;;
+esac
+AC_MSG_RESULT($OS_TYPE)
+AM_CONDITIONAL(OS_LINUX, test $OS_TYPE = LINUX)
+AM_CONDITIONAL(OS_BSD, test $OS_TYPE = BSD)
+AM_CONDITIONAL(OS_SOLARIS, test $OS_TYPE = Solaris)
+
 
 AC_MSG_CHECKING(for sa_len in struct sockaddr)
 AC_TRY_COMPILE([
@@ -1079,6 +1106,7 @@ Flags:
   CXXFLAGS:      $CXXFLAGS
   LDFLAGS:       $LDFLAGS
   B10_CXXFLAGS:  $B10_CXXFLAGS
+  OS Family:     $OS_TYPE
 dnl includes too
   Python:        ${PYTHON_INCLUDES}
                  ${PYTHON_CXXFLAGS}

src/bin/dhcp6/dhcp6_srv.cc

@@ -30,7 +30,17 @@ Dhcpv6Srv::Dhcpv6Srv() {
 
     // first call to instance() will create IfaceMgr (it's a singleton)
     // it may throw something if things go wrong
-    IfaceMgr::instance();
+    try {
+	IfaceMgr::instance();
+    } catch (const std::exception &e) {
+	cout << "Failed to instantiate InterfaceManager. Aborting." << endl;
+	shutdown = true;
+    }
+
+    if (IfaceMgr::instance().countIfaces() == 0) {
+	cout << "Failed to detect any network interfaces. Aborting." << endl;
+	shutdown = true;
+    }
 
     /// @todo: instantiate LeaseMgr here once it is imlpemented.
 

src/lib/dhcp/Makefile.am

@@ -19,6 +19,15 @@ libdhcp_la_SOURCES += dhcp6.h dhcp4.h
 libdhcp_la_SOURCES += pkt6.cc pkt6.h
 libdhcp_la_SOURCES += pkt4.cc pkt4.h
 
+if OS_LINUX
+libdhcp_la_SOURCES += iface_mgr_linux.cc
+endif
+
+if OS_BSD
+libdhcp_la_SOURCES += iface_mgr_bsd.cc
+endif
+
+
 EXTRA_DIST  = README
 #EXTRA_DIST += log_messages.mes
 

src/lib/dhcp/iface_mgr.cc

@@ -52,8 +52,10 @@ IfaceMgr::instance() {
 }
 
 IfaceMgr::Iface::Iface(const std::string& name, int ifindex)
-    :name_(name), ifindex_(ifindex), mac_len_(0) {
-
+    :name_(name), ifindex_(ifindex), mac_len_(0), flag_loopback_(false),
+     flag_up_(false), flag_running_(false), flag_multicast_(false),
+     flag_broadcast_(false), flags_(0), hardware_type_(0)
+{
     memset(mac_, 0, sizeof(mac_));
 }
 
@@ -71,7 +73,7 @@ IfaceMgr::Iface::getPlainMac() const {
     tmp << hex;
     for (int i = 0; i < mac_len_; i++) {
         tmp.width(2);
-        tmp << mac_[i];
+        tmp <<  int(mac_[i]);
         if (i < mac_len_-1) {
             tmp << ":";
         }
@@ -95,7 +97,7 @@ IfaceMgr::IfaceMgr()
 
         detectIfaces();
 
-        if (!openSockets()) {
+        if (!openSockets6()) {
             isc_throw(Unexpected, "Failed to open/bind sockets.");
         }
     } catch (const std::exception& ex) {
@@ -105,7 +107,7 @@ IfaceMgr::IfaceMgr()
         // interface detection is implemented. Otherwise
         // it is not possible to run tests in a portable
         // way (see detectIfaces() method).
-        // throw ex;
+        throw ex;
     }
 }
 
@@ -115,7 +117,7 @@ IfaceMgr::~IfaceMgr() {
 }
 
 void
-IfaceMgr::detectIfaces() {
+IfaceMgr::stubDetectIfaces() {
     string ifaceName, linkLocal;
 
     // TODO do the actual detection. Currently interface detection is faked
@@ -154,8 +156,13 @@ IfaceMgr::detectIfaces() {
     }
 }
 
-bool
-IfaceMgr::openSockets() {
+#if !defined(OS_LINUX) && !defined(OS_BSD)
+void IfaceMgr::detectIfaces() {
+    stubDetectIfaces();
+}
+#endif
+
+bool IfaceMgr::openSockets6() {
     int sock;
 
     for (IfaceLst::iterator iface=ifaces_.begin();
@@ -166,6 +173,11 @@ IfaceMgr::openSockets() {
              addr!=iface->addrs_.end();
              ++addr) {
 
+            // skip IPv4 addresses
+            if (addr->getFamily() != AF_INET6) {
+                continue;
+            }
+
             sock = openSocket(iface->name_, *addr,
                               DHCP6_SERVER_PORT);
             if (sock<0) {
@@ -194,14 +206,23 @@ IfaceMgr::printIfaces(std::ostream& out /*= std::cout*/) {
     for (IfaceLst::const_iterator iface=ifaces_.begin();
          iface!=ifaces_.end();
          ++iface) {
-        out << "Detected interface " << iface->getFullName() << endl;
+
+        out << "Detected interface " << iface->getFullName()
+             << ", hwtype=" << iface->hardware_type_ << ", maclen=" << iface->mac_len_
+             << ", mac=" << iface->getPlainMac() << endl;
+        out << "flags=" << hex << iface->flags_ << dec << "("
+            << (iface->flag_loopback_?"LOOPBACK ":"")
+            << (iface->flag_up_?"UP ":"")
+            << (iface->flag_running_?"RUNNING ":"")
+            << (iface->flag_multicast_?"MULTICAST ":"")
+            << (iface->flag_broadcast_?"BROADCAST ":"")
+            << ")" << endl;
         out << "  " << iface->addrs_.size() << " addr(s):" << endl;
         for (Addr6Lst::const_iterator addr=iface->addrs_.begin();
              addr != iface->addrs_.end();
              ++addr) {
             out << "  " << addr->toText() << endl;
         }
-        out << "  mac: " << iface->getPlainMac() << endl;
     }
 }
 

src/lib/dhcp/iface_mgr.h

@@ -54,6 +54,8 @@ public:
         /// returns link-layer address a plain text
         std::string getPlainMac() const;
 
+        void setFlags(uint32_t flags);
+
         /// network interface name
         std::string name_;
 
@@ -69,6 +71,29 @@ public:
         /// length of link-layer address (usually 6)
         int mac_len_;
 
+        /// specifies if selected interface is loopback
+        bool flag_loopback_;
+
+        /// specifies if selected interface is up
+        bool flag_up_;
+
+        /// flag specifies if selected interface is running
+        /// (e.g. cable plugged in, wifi associated)
+        bool flag_running_;
+
+        /// flag specifies if selected interface is multicast capable
+        bool flag_multicast_;
+
+        /// flag specifies if selected interface is broadcast capable
+        bool flag_broadcast_;
+
+        /// interface flags (this value is as is returned by OS,
+        /// it may mean different things on different OSes)
+        uint32_t flags_;
+
+        /// hardware type
+        uint16_t hardware_type_;
+
         /// socket used to sending data
         int sendsock_;
 
@@ -140,6 +165,11 @@ public:
     /// @return Pkt6 object representing received packet (or NULL)
     boost::shared_ptr<Pkt6> receive();
 
+    /// @brief returns number of detected interfaces
+    ///
+    /// @return number of detected interfaces
+    uint16_t countIfaces() { return ifaces_.size(); }
+
     // don't use private, we need derived classes in tests
 protected:
 
@@ -159,6 +189,15 @@ protected:
     void
     detectIfaces();
 
+    /// @brief Stub implementation of network interface detection.
+    ///
+    /// This implementations reads a single line from interfaces.txt file
+    /// and pretends to detect such interface. First interface name and
+    /// link-local IPv6 address or IPv4 address is read from the
+    /// intefaces.txt file.
+    void
+    stubDetectIfaces();
+
     ///
     /// Opens UDP/IPv6 socket and binds it to address, interface and port.
     ///
@@ -199,7 +238,7 @@ protected:
 private:
     /// Opens sockets on detected interfaces.
     bool
-    openSockets();
+    openSockets6();
 
     /// creates a single instance of this class (a singleton implementation)
     static void

src/lib/dhcp/iface_mgr_bsd.cc

+// Copyright (C) 2011  Internet Systems Consortium, Inc. ("ISC")
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#include <dhcp6/iface_mgr.h>
+#include <exceptions/exceptions.h>
+
+using namespace std;
+using namespace isc;
+using namespace isc::asiolink;
+using namespace isc::dhcp;
+
+#if !defined(OS_BSD)
+/// There are several detectIfaces() implementations for specific
+/// Operating Systems. This one is specific to BSD. It works on
+/// BSD only, so it does not make sense to try to compile it somewhere
+/// else. In particular, Makefile.am includes only one iface_mgr_{OS_TYPE}.cc
+/// file.
+
+#error "Attempt to compile iface_mgr_bsd.cc on non-BSD system!"
+
+#endif
+
+namespace isc {
+
+void
+IfaceMgr::detectIfaces() {
+    // TODO do the actual detection on BSDs. Currently just calling
+    // stub implementation.
+    stubDetectIfaces();
+}
+
+}

src/lib/dhcp/iface_mgr_linux.cc

+// Copyright (C) 2011  Internet Systems Consortium, Inc. ("ISC")
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#include <dhcp/iface_mgr.h>
+#include <exceptions/exceptions.h>
+
+#include <net/if.h>
+#include <linux/if_link.h>
+#include <linux/rtnetlink.h>
+
+using namespace std;
+using namespace isc;
+using namespace isc::asiolink;
+using namespace isc::dhcp;
+
+#if !defined(OS_LINUX)
+/// There are several detectIfaces() implementations for specific
+/// Operating Systems. This one is specific to Linux. It works on
+/// Linux only, so it does not make sense to try to compile it somewhere
+/// else. In particular, Makefile.am includes only one iface_mgr_{OS_TYPE}.cc
+/// file.
+
+#error "Attempt to compile iface_mgr_linux.cc on non-Linux system!"
+#endif
+
+struct rtnl_handle
+{
+	int			fd;
+	struct sockaddr_nl	local;
+	struct sockaddr_nl	peer;
+	__u32			seq;
+	__u32			dump;
+};
+
+struct nlmsg_list
+{
+	struct nlmsg_list *next;
+	struct nlmsghdr	  h;
+};
+
+const int sndbuf = 32768;
+const int rcvbuf = 32768;
+
+namespace isc {
+
+
+void rtnl_open_socket(struct rtnl_handle& handle) {
+    // equivalent of rtnl_open
+    handle.fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+    if (handle.fd < 0) {
+	isc_throw(Unexpected, "Failed to create NETLINK socket.");
+    }
+    
+    if (setsockopt(handle.fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf)) < 0) {
+	isc_throw(Unexpected, "Failed to set send buffer in NETLINK socket.");
+    }
+    
+    if (setsockopt(handle.fd, SOL_SOCKET, SO_RCVBUF, &sndbuf, sizeof(rcvbuf)) < 0) {
+	isc_throw(Unexpected, "Failed to set receive buffer in NETLINK socket.");
+    }
+    
+    memset(&handle.local, 0, sizeof(handle.local));
+    handle.local.nl_family = AF_NETLINK;
+    handle.local.nl_groups = 0;
+
+    if (bind(handle.fd, (struct sockaddr*)&handle.local, sizeof(handle.local)) < 0) {
+	isc_throw(Unexpected, "Failed to bind netlink socket.");
+    }
+
+    socklen_t addr_len = sizeof(handle.local);
+    if (getsockname(handle.fd, (struct sockaddr*)&handle.local, &addr_len) < 0) {
+	isc_throw(Unexpected, "Getsockname for netlink socket failed.");
+    }
+
+    // just 2 sanity checks and we are done
+    if ( (addr_len != sizeof(handle.local)) ||
+	 (handle.local.nl_family != AF_NETLINK) ) {
+	isc_throw(Unexpected, "getsockname() returned unexpected data for netlink socket.");
+    }
+}
+
+// sends request over NETLINK socket
+void rtnl_send_request(struct rtnl_handle& handle,
+		       int family, int type) {
+    struct {
+	struct nlmsghdr nlh;
+	struct rtgenmsg g;
+    } req;
+    struct sockaddr_nl nladdr;
+    
+    memset(&nladdr, 0, sizeof(nladdr));
+    nladdr.nl_family = AF_NETLINK;
+    
+    memset(&req, 0, sizeof(req));
+    req.nlh.nlmsg_len = sizeof(req);
+    req.nlh.nlmsg_type = type;
+    req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
+    req.nlh.nlmsg_pid = 0;
+    req.nlh.nlmsg_seq = handle.dump = ++handle.seq;
+    req.g.rtgen_family = family;
+    
+    int status =  sendto(handle.fd, (void*)&req, sizeof(req), 0,
+			 (struct sockaddr*)&nladdr, sizeof(nladdr));
+
+    if (status<0) {
+	isc_throw(Unexpected, "Failed to send " << sizeof(nladdr) << " bytes over netlink socket.");
+    }
+}
+
+void rtnl_store_reply(/*const struct sockaddr_nl *who,*/ struct nlmsghdr *n, struct nlmsg_list** linfo)
+{
+    struct nlmsg_list *h;
+    struct nlmsg_list **lp;
+    
+    h = (nlmsg_list*)malloc(n->nlmsg_len+sizeof(void*));
+    if (h == NULL) {
+	isc_throw(Unexpected, "Failed to allocate " << n->nlmsg_len+sizeof(void*)
+		  << " bytes.");
+    }
+    
+    memcpy(&h->h, n, n->nlmsg_len);
+    h->next = NULL;
+    
+    for (lp = linfo; *lp; lp = &(*lp)->next) /* NOTHING */;
+    *lp = h;
+    
+    // ll_remember_index(who, n, NULL);
+    // return 0;
+}
+
+void parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
+{
+    memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
+    while (RTA_OK(rta, len)) {
+	if (rta->rta_type <= max)
+	    tb[rta->rta_type] = rta;
+	rta = RTA_NEXT(rta,len);
+    }
+    if (len) {
+	isc_throw(Unexpected, "Failed to parse RTATTR in netlink message.");
+    }
+}
+
+
+ void ipaddrs_get(IfaceMgr::Iface& iface, struct nlmsg_list *ainfo) {
+    uint8_t addr[16];
+    struct rtattr * rta_tb[IFA_MAX+1];
+
+    for ( ;ainfo ;  ainfo = ainfo->next) {
+	struct nlmsghdr *n = &ainfo->h;
+	struct ifaddrmsg *ifa = (ifaddrmsg*)NLMSG_DATA(n);
+
+	// these are not the addresses you are looking for
+	if ( ifa->ifa_index != iface.ifindex_) {
+	    continue;
+	}
+
+	if ( ifa->ifa_family == AF_INET6 ) {
+	    memset(rta_tb, 0, sizeof(rta_tb));
+	    parse_rtattr(rta_tb, IFA_MAX, IFA_RTA(ifa), n->nlmsg_len - NLMSG_LENGTH(sizeof(*ifa)));
+	    if (!rta_tb[IFA_LOCAL])   
+		rta_tb[IFA_LOCAL]   = rta_tb[IFA_ADDRESS];
+	    if (!rta_tb[IFA_ADDRESS]) 
+		rta_tb[IFA_ADDRESS] = rta_tb[IFA_LOCAL];
+	    
+	    memcpy(addr,(char*)RTA_DATA(rta_tb[IFLA_ADDRESS]),16);
+	    IOAddress a = IOAddress::from_bytes(AF_INET6, addr);
+	    iface.addrs_.push_back(a);
+
+	    /// TODO: Read lifetimes of configured addresses
+	}
+
+	if ( ifa->ifa_family == AF_INET ) {
+	    memset(rta_tb, 0, sizeof(rta_tb));
+	    parse_rtattr(rta_tb, IFA_MAX, IFA_RTA(ifa), n->nlmsg_len - NLMSG_LENGTH(sizeof(*ifa)));
+	    if (!rta_tb[IFA_LOCAL])   
+		rta_tb[IFA_LOCAL]   = rta_tb[IFA_ADDRESS];
+	    if (!rta_tb[IFA_ADDRESS]) 
+		rta_tb[IFA_ADDRESS] = rta_tb[IFA_LOCAL];
+	    
+	    memcpy(addr,(char*)RTA_DATA(rta_tb[IFLA_ADDRESS]),4);
+	    IOAddress a = IOAddress::from_bytes(AF_INET, addr);
+	    iface.addrs_.push_back(a);
+	}
+
+
+    }
+}
+
+
+void rtnl_process_reply(struct rtnl_handle &rth,
+		       struct nlmsg_list *&info) {
+
+    struct sockaddr_nl nladdr;
+    struct iovec iov;
+    struct msghdr msg;
+    memset(&msg, 0, sizeof(struct msghdr));
+    msg.msg_name = &nladdr;
+    msg.msg_namelen = sizeof(nladdr);
+    msg.msg_iov = &iov;
+    msg.msg_iovlen = 1;
+
+    char buf[rcvbuf];
+    
+    iov.iov_base = buf;
+    while (1) {
+	int status;
+	struct nlmsghdr *h;
+	
+	iov.iov_len = sizeof(buf);
+	status = recvmsg(rth.fd, &msg, 0);
+	
+	if (status < 0) {
+	    if (errno == EINTR)
+		continue;
+	    isc_throw(Unexpected, "Overrun while processing reply from netlink socket.");
+	}
+	
+	if (status == 0) {
+	    isc_throw(Unexpected, "EOF while reading netlink socket.");
+	}
+	
+	h = (struct nlmsghdr*)buf;
+	while (NLMSG_OK(h, status)) {
+
+	    // why we received this anyway?
+	    if (nladdr.nl_pid != 0 ||
+		h->nlmsg_pid != rth.local.nl_pid ||
+		h->nlmsg_seq != rth.dump) {
+		h = NLMSG_NEXT(h, status);
+		continue;
+	    }
+		    
+	    if (h->nlmsg_type == NLMSG_DONE) {
+		// end of message
+		return;
+	    }
+
+	    if (h->nlmsg_type == NLMSG_ERROR) {
+		struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
+		if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
+		    // we are really out of luck here. We can't even say what is
+		    // wrong as error message is truncated. D'oh.
+		    isc_throw(Unexpected, "Netlink reply read failed.");
+		} else {
+		    isc_throw(Unexpected, "Netlink reply read error " << -err->error);
+		}
+		// never happens we throw before we reach here
+		return;
+	    }
+
+	    // store the data 
+	    rtnl_store_reply(/*&nladdr,*/ h, &info);
+	    
+	    h = NLMSG_NEXT(h, status);
+	}
+	if (msg.msg_flags & MSG_TRUNC) {
+	    isc_throw(Unexpected, "Message received over netlink truncated.");
+	}
+	if (status) {
+	    isc_throw(Unexpected, "Trailing garbage of " << status << " bytes received over netlink.");
+	}
+    }
+}
+
+void release_list(struct nlmsg_list *n) {
+    struct nlmsg_list *tmp;
+    while (n) {
+	tmp = n->next;
+	free(n);
+	n = tmp;
+    }
+}
+
+    
+void
+IfaceMgr::detectIfaces() {
+
+    cout << "Linux: detecting interfaces." << endl;
+
+    struct nlmsg_list *linfo = NULL;
+    struct nlmsg_list *ainfo = NULL;
+    struct nlmsg_list *l = NULL;
+    struct rtnl_handle rth;
+
+    /* required to display information about interface */
+    struct ifinfomsg *ifi = NULL;
+    struct rtattr * tb[IFLA_MAX+1];
+    int len = 0;
+    memset(tb, 0, sizeof(tb));
+    memset(&rth,0, sizeof(rth));
+
+    // open socket
+    rtnl_open_socket(rth);
+
+    // now we have open functional socket, let's use it!
+    rtnl_send_request(rth, AF_PACKET, RTM_GETLINK);
+
+    // process reply
+    rtnl_process_reply(rth, linfo);
+    //rtnl_dump_filter(&rth, store_nlmsg, &linfo, NULL, NULL);
+    
+    /* 2nd attribute: AF_UNSPEC, AF_INET, AF_INET6 */
+    rtnl_send_request(rth, AF_UNSPEC, RTM_GETADDR);
+    rtnl_process_reply(rth, ainfo);
+
+    /* build list with interface names */
+    for (l=linfo; l; l = l->next) {
+	ifi = (ifinfomsg*)NLMSG_DATA(&l->h);
+	len = (&l->h)->nlmsg_len;
+	len -= NLMSG_LENGTH(sizeof(*ifi));
+	parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
+
+	Iface* iface = new Iface(string( (char*)RTA_DATA(tb[IFLA_IFNAME])), ifi->ifi_index);
+