[2902] Unit tests for linux packet filtering.

src/lib/dhcp/tests/Makefile.am

@@ -44,6 +44,7 @@ libdhcp___unittests_SOURCES += option_space_unittest.cc
 libdhcp___unittests_SOURCES += pkt4_unittest.cc
 libdhcp___unittests_SOURCES += pkt6_unittest.cc
 libdhcp___unittests_SOURCES += pkt_filter_inet_unittest.cc
+libdhcp___unittests_SOURCES += pkt_filter_lpf_unittest.cc
 libdhcp___unittests_SOURCES += protocol_util_unittest.cc
 libdhcp___unittests_SOURCES += duid_unittest.cc
 

src/lib/dhcp/tests/pkt_filter_lpf_unittest.cc

+// Copyright (C) 2013 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 <config.h>
+#include <asiolink/io_address.h>
+#include <dhcp/iface_mgr.h>
+#include <dhcp/pkt4.h>
+#include <dhcp/pkt_filter_lpf.h>
+#include <dhcp/protocol_util.h>
+#include <util/buffer.h>
+
+#include <gtest/gtest.h>
+
+#include <linux/if_packet.h>
+#include <sys/socket.h>
+
+using namespace isc::asiolink;
+using namespace isc::dhcp;
+using namespace isc::util;
+
+namespace {
+
+/// Port number used by tests.
+const uint16_t PORT = 10067;
+/// Size of the buffer holding received packets.
+const size_t RECV_BUF_SIZE = 2048;
+
+/// This class handles has simple algorithm checking
+/// presence of loopback interface and initializing
+/// its index.
+class PktFilterLPFTest : public ::testing::Test {
+public:
+    PktFilterLPFTest() {
+        // Initialize ifname_ and ifindex_.
+        loInit();
+    }
+
+    ~PktFilterLPFTest() {
+        // Cleanup after each test. This guarantees
+        // that the socket does not hang after a test.
+        close(socket_);
+    }
+
+    /// @brief Detect loopback interface.
+    ///
+    /// @todo this function will be removed once cross-OS interface
+    /// detection is implemented
+    void loInit() {
+        if (if_nametoindex("lo") > 0) {
+            ifname_ = "lo";
+            ifindex_ = if_nametoindex("lo");
+
+        } else if (if_nametoindex("lo0") > 0) {
+            ifname_ = "lo0";
+            ifindex_ = if_nametoindex("lo0");
+
+        } else {
+            std::cout << "Failed to detect loopback interface. Neither "
+                      << "lo nor lo0 worked. Giving up." << std::endl;
+            FAIL();
+
+
+
+        }
+    }
+
+    std::string ifname_; ///< Loopback interface name
+    uint16_t ifindex_;   ///< Loopback interface index.
+    int socket_;         ///< Socket descriptor.
+
+};
+
+// All tests below require root privileges to execute successfully. If
+// they are run as non-root user they will fail due to insufficient privileges
+// to open raw network sockets. Therefore, they should remain disabled by default
+// and "DISABLED_" tags should not be removed. If one is willing to run these
+// tests please run "make check" as root and enable execution of disabled tests
+// by setting GTEST_ALSO_RUN_DISABLED_TESTS to a value other than 0. In order
+// to run tests from this particular file, set the GTEST_FILTER environmental
+// variable to "PktFilterLPFTest.*" apart from GTEST_ALSO_RUN_DISABLED_TESTS
+// setting.
+
+// This test verifies that the raw AF_PACKET family socket can
+// be opened and bound to the specific interface.
+TEST_F(PktFilterLPFTest, DISABLED_openSocket) {
+    // Create object representing loopback interface.
+    Iface iface(ifname_, ifindex_);
+    // Set loopback address.
+    IOAddress addr("127.0.0.1");
+
+    // Try to open socket.
+    PktFilterLPF pkt_filter;
+    socket_ = pkt_filter.openSocket(iface, addr, PORT, false, false);
+    // Check that socket has been opened.
+    ASSERT_GE(socket_, 0);
+
+    // Verify that the socket belongs to AF_PACKET family.
+    sockaddr_ll sock_address;
+    socklen_t sock_address_len = sizeof(sock_address);
+    ASSERT_EQ(0, getsockname(socket_, reinterpret_cast<sockaddr*>(&sock_address),
+                             &sock_address_len));
+    EXPECT_EQ(AF_PACKET, sock_address.sll_family);
+
+    // Verify that the socket is bound to appropriate interface.
+    EXPECT_EQ(ifindex_, sock_address.sll_ifindex);
+
+    // Verify that the socket has SOCK_RAW type.
+    int sock_type;
+    socklen_t sock_type_len = sizeof(sock_type);
+    ASSERT_EQ(0, getsockopt(socket_, SOL_SOCKET, SO_TYPE, &sock_type, &sock_type_len));
+    EXPECT_EQ(SOCK_RAW, sock_type);
+}
+
+// This test verifies correctness of sending DHCP packet through the raw
+// socket, whereby all IP stack headers are hand-crafted.
+TEST_F(PktFilterLPFTest, DISABLED_send) {
+        // Let's create a DHCPv4 packet.
+    Pkt4Ptr pkt(new Pkt4(DHCPOFFER, 0));
+    ASSERT_TRUE(pkt);
+
+    // Set required fields.
+    pkt->setLocalAddr(IOAddress("127.0.0.1"));
+    pkt->setRemotePort(PORT);
+    pkt->setLocalPort(PORT + 1);
+    pkt->setIndex(ifindex_);
+    pkt->setIface(ifname_);
+    pkt->setHops(6);
+    pkt->setSecs(42);
+    pkt->setCiaddr(IOAddress("192.0.2.1"));
+    pkt->setSiaddr(IOAddress("192.0.2.2"));
+    pkt->setYiaddr(IOAddress("192.0.2.3"));
+    pkt->setGiaddr(IOAddress("192.0.2.4"));
+
+    // Create the on-wire data.
+    ASSERT_NO_THROW(pkt->pack());
+
+    // Packet will be sent over loopback interface.
+    Iface iface(ifname_, ifindex_);
+    IOAddress addr("127.0.0.1");
+
+    // Create an instance of the class which we are testing.
+    PktFilterLPF pkt_filter;
+    // Open socket. We don't check that the socket has appropriate
+    // options and family set because we have checked that in the
+    // openSocket test already.
+    socket_ = pkt_filter.openSocket(iface, addr, PORT, false, false);
+    ASSERT_GE(socket_, 0);
+
+    // Send the packet over the socket.
+    ASSERT_NO_THROW(pkt_filter.send(iface, socket_, pkt));
+
+    // Read the data from socket.
+    fd_set readfds;
+    FD_ZERO(&readfds);
+    FD_SET(socket_, &readfds);
+    
+    struct timeval timeout;
+    timeout.tv_sec = 5;
+    timeout.tv_usec = 0;
+    int result = select(socket_ + 1, &readfds, NULL, NULL, &timeout);
+    // We should receive some data from loopback interface.
+    ASSERT_GT(result, 0);
+
+    // Get the actual data.
+    uint8_t rcv_buf[RECV_BUF_SIZE];
+    result = recv(socket_, rcv_buf, RECV_BUF_SIZE, 0);
+    ASSERT_GT(result, 0);
+
+    Pkt4Ptr dummy_pkt = Pkt4Ptr(new Pkt4(DHCPDISCOVER, 0));
+
+    InputBuffer buf(rcv_buf, result);
+
+    // Decode ethernet, ip and udp headers.
+    decodeEthernetHeader(buf, dummy_pkt);
+    decodeIpUdpHeader(buf, dummy_pkt);
+
+    // Create the DHCPv4 packet from the received data.
+    std::vector<uint8_t> dhcp_buf;
+    buf.readVector(dhcp_buf, buf.getLength() - buf.getPosition());
+    Pkt4Ptr rcvd_pkt(new Pkt4(&dhcp_buf[0], dhcp_buf.size()));
+    ASSERT_TRUE(rcvd_pkt);
+
+    // Parse the packet.
+    ASSERT_NO_THROW(rcvd_pkt->unpack());
+
+    // Verify that the received packet matches sent packet.
+    EXPECT_EQ(pkt->getHops(), rcvd_pkt->getHops());
+    EXPECT_EQ(pkt->getOp(),   rcvd_pkt->getOp());
+    EXPECT_EQ(pkt->getSecs(), rcvd_pkt->getSecs());
+    EXPECT_EQ(pkt->getFlags(), rcvd_pkt->getFlags());
+    EXPECT_EQ(pkt->getCiaddr(), rcvd_pkt->getCiaddr());
+    EXPECT_EQ(pkt->getSiaddr(), rcvd_pkt->getSiaddr());
+    EXPECT_EQ(pkt->getYiaddr(), rcvd_pkt->getYiaddr());
+    EXPECT_EQ(pkt->getGiaddr(), rcvd_pkt->getGiaddr());
+    EXPECT_EQ(pkt->getTransid(), rcvd_pkt->getTransid());
+    EXPECT_TRUE(pkt->getSname() == rcvd_pkt->getSname());
+    EXPECT_TRUE(pkt->getFile() == rcvd_pkt->getFile());
+    EXPECT_EQ(pkt->getHtype(), rcvd_pkt->getHtype());
+    EXPECT_EQ(pkt->getHlen(), rcvd_pkt->getHlen());
+}
+
+// This test verifies correctness of reception of the DHCP packet over
+// raw socket, whereby all IP stack headers are hand-crafted.
+TEST_F(PktFilterLPFTest, DISABLED_receive) {
+
+    // Let's create a DHCPv4 packet.
+    Pkt4Ptr pkt(new Pkt4(DHCPOFFER, 0));
+    ASSERT_TRUE(pkt);
+
+    // Set required fields.
+    pkt->setLocalAddr(IOAddress("127.0.0.1"));
+    pkt->setRemotePort(PORT);
+    pkt->setLocalPort(PORT + 1);
+    pkt->setIndex(ifindex_);
+    pkt->setIface(ifname_);
+    pkt->setHops(6);
+    pkt->setSecs(42);
+    pkt->setCiaddr(IOAddress("192.0.2.1"));
+    pkt->setSiaddr(IOAddress("192.0.2.2"));
+    pkt->setYiaddr(IOAddress("192.0.2.3"));
+    pkt->setGiaddr(IOAddress("192.0.2.4"));
+
+    // Create the on-wire data.
+    ASSERT_NO_THROW(pkt->pack());
+
+    // Packet will be sent over loopback interface.
+    Iface iface(ifname_, ifindex_);
+    IOAddress addr("127.0.0.1");
+
+    // Create an instance of the class which we are testing.
+    PktFilterLPF pkt_filter;
+    // Open socket. We don't check that the socket has appropriate
+    // options and family set because we have checked that in the
+    // openSocket test already.
+    socket_ = pkt_filter.openSocket(iface, addr, PORT, false, false);
+    ASSERT_GE(socket_, 0);
+
+    // Send the packet over the socket.
+    ASSERT_NO_THROW(pkt_filter.send(iface, socket_, pkt));
+
+    // Receive the packet.
+    SocketInfo socket_info(socket_, IOAddress("127.0.0.1"), PORT);
+    Pkt4Ptr rcvd_pkt = pkt_filter.receive(iface, socket_info);
+    // Check that the packet has been correctly received.
+    ASSERT_TRUE(rcvd_pkt);
+
+    // Parse the packet.
+    ASSERT_NO_THROW(rcvd_pkt->unpack());
+
+    // Verify that the received packet matches sent packet.
+    EXPECT_EQ(pkt->getHops(), rcvd_pkt->getHops());
+    EXPECT_EQ(pkt->getOp(),   rcvd_pkt->getOp());
+    EXPECT_EQ(pkt->getSecs(), rcvd_pkt->getSecs());
+    EXPECT_EQ(pkt->getFlags(), rcvd_pkt->getFlags());
+    EXPECT_EQ(pkt->getCiaddr(), rcvd_pkt->getCiaddr());
+    EXPECT_EQ(pkt->getSiaddr(), rcvd_pkt->getSiaddr());
+    EXPECT_EQ(pkt->getYiaddr(), rcvd_pkt->getYiaddr());
+    EXPECT_EQ(pkt->getGiaddr(), rcvd_pkt->getGiaddr());
+    EXPECT_EQ(pkt->getTransid(), rcvd_pkt->getTransid());
+    EXPECT_TRUE(pkt->getSname() == rcvd_pkt->getSname());
+    EXPECT_TRUE(pkt->getFile() == rcvd_pkt->getFile());
+    EXPECT_EQ(pkt->getHtype(), rcvd_pkt->getHtype());
+    EXPECT_EQ(pkt->getHlen(), rcvd_pkt->getHlen());
+}
+
+} // anonymous namespace