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Commit 68b6c2b5 authored by Marcin Siodelski's avatar Marcin Siodelski
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[3252] Addressed review comments.

parent d0da7ccd
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Showing with 63 additions and 32 deletions
src/lib/dhcp/iface_mgr.cc
View file @ 68b6c2b5
......@@ -60,14 +60,16 @@
/// @param handler Error handler function to be called or NULL to indicate
/// that exception should be thrown instead.
/// @param stream stream object holding an error string.
#define ifacemgr_error(ex_type, handler, stream) \
#define IFACEMGR_ERROR(ex_type, handler, stream) \
{ \
std::ostringstream oss__; \
oss__ << stream; \
if (handler) { \
handler(oss__.str()); \
} else { \
isc_throw(ex_type, oss__); \
}
} \
} \
using namespace std;
using namespace isc::asiolink;
......@@ -405,7 +407,7 @@ IfaceMgr::openSockets4(const uint16_t port, const bool use_bcast,
// bind to INADDR_ANY address but we can do it only once. Thus,
// if one socket has been bound we can't do it any further.
if (!bind_to_device && bcast_num > 0) {
ifacemgr_error(SocketConfigError, error_handler,
IFACEMGR_ERROR(SocketConfigError, error_handler,
"SO_BINDTODEVICE socket option is"
" not supported on this OS;"
" therefore, DHCP server can only"
......@@ -419,7 +421,7 @@ IfaceMgr::openSockets4(const uint16_t port, const bool use_bcast,
// open at least one more.
openSocket(iface->getName(), *addr, port, true, true);
} catch (const Exception& ex) {
ifacemgr_error(SocketConfigError, error_handler,
IFACEMGR_ERROR(SocketConfigError, error_handler,
"failed to open socket on interface "
<< iface->getName() << ", reason: "
<< ex.what());
......@@ -439,7 +441,7 @@ IfaceMgr::openSockets4(const uint16_t port, const bool use_bcast,
// Not broadcast capable, do not set broadcast flags.
openSocket(iface->getName(), *addr, port, false, false);
} catch (const Exception& ex) {
ifacemgr_error(SocketConfigError, error_handler,
IFACEMGR_ERROR(SocketConfigError, error_handler,
"failed to open socket on interface "
<< iface->getName() << ", reason: "
<< ex.what());
......@@ -479,7 +481,7 @@ IfaceMgr::openSockets6(const uint16_t port,
openSocket(iface->getName(), *addr, port);
} catch (const Exception& ex) {
ifacemgr_error(SocketConfigError, error_handler,
IFACEMGR_ERROR(SocketConfigError, error_handler,
"Failed to open unicast socket on interface "
<< iface->getName() << ", reason: "
<< ex.what());
......@@ -517,13 +519,23 @@ IfaceMgr::openSockets6(const uint16_t port,
// it for some odd use cases which may utilize non-multicast
// interfaces. Perhaps a warning should be emitted if the
// interface is not a multicast one.
// The sock variable will hold a socket descriptor. It may be
// used to close a socket if the function fails to bind to
// multicast address on Linux systems. Because we only bind
// a socket to multicast address on Linux, on other systems
// the sock variable will be initialized but unused. We have
// to suppress the cppcheck warning which shows up on non-Linux
// systems.
// cppcheck-suppress variableScope
int sock;
try {
// cppcheck-suppress unreadVariable
sock = openSocket(iface->getName(), *addr, port,
iface->flag_multicast_);
} catch (const Exception& ex) {
ifacemgr_error(SocketConfigError, error_handler,
IFACEMGR_ERROR(SocketConfigError, error_handler,
"Failed to open link-local socket on "
" interface " << iface->getName() << ": "
<< ex.what());
......@@ -545,7 +557,7 @@ IfaceMgr::openSockets6(const uint16_t port,
} catch (const Exception& ex) {
// Delete previously opened socket.
iface->delSocket(sock);
ifacemgr_error(SocketConfigError, error_handler,
IFACEMGR_ERROR(SocketConfigError, error_handler,
"Failed to open multicast socket on"
" interface " << iface->getName()
<< ", reason: " << ex.what());
......
src/lib/dhcp/iface_mgr.h
View file @ 68b6c2b5
......@@ -629,18 +629,33 @@ public:
/// @brief Opens IPv6 sockets on detected interfaces.
///
/// @todo This function will throw an exception immediately when a socket
/// fails to open. This is undersired behavior because it will preclude
/// other sockets from opening. We should strive to provide similar mechanism
/// that has been introduced for V4 sockets. If socket creation fails the
/// appropriate error handler is called and once the handler returns the
/// function contnues to open other sockets. The change in the IfaceMgr
/// is quite straight forward and it is proven to work for V4. However,
/// unit testing it is a bit involved, because for unit testing we need
/// a replacement of the openSocket6 function which will mimic the
/// behavior of the real socket opening. For the V4 we have the means to
/// to achieve that with the replaceable PktFilter class. For V6, the
/// implementation is hardcoded in the openSocket6.
/// On the systems with multiple interfaces, it is often desired that the
/// failure to open a socket on a particular interface doesn't cause a
/// fatal error and sockets should be opened on remaining interfaces.
/// However, the warning about the failure for the particular socket should
/// be communicated to the caller. The libdhcp++ is a common library with
/// no logger associated with it. Most of the functions in this library
/// communicate errors via exceptions. In case of openSockets6 function
/// exception must not be thrown if the function is supposed to continue
/// opening sockets, despite an error. Therefore, if such a behavior is
/// desired, the error handler function can be passed as a parameter.
/// This error handler is called (if present) with an error string.
/// Typically, error handler will simply log an error using an application
/// logger, but it can do more sophisticated error handling too.
///
/// @todo It is possible that additional parameters will have to be added
/// to the error handler, e.g. Iface if it was really supposed to do
/// some more sophisticated error handling.
///
/// If the error handler is not installed (is NULL), the exception is thrown
/// for each failure (default behavior).
///
/// @warning This function does not check if there has been any sockets
/// already open by the @c IfaceMgr. Therefore a caller should call
/// @c IfaceMgr::closeSockets(AF_INET6) before calling this function.
/// If there are any sockets open, the function may either throw an
/// exception or invoke an error handler on attempt to bind the new socket
/// to the same address and port.
///
/// @param port specifies port number (usually DHCP6_SERVER_PORT)
/// @param error_handler A pointer to an error handler function which is
......@@ -705,6 +720,13 @@ public:
/// If the error handler is not installed (is NULL), the exception is thrown
/// for each failure (default behavior).
///
/// @warning This function does not check if there has been any sockets
/// already open by the @c IfaceMgr. Therefore a caller should call
/// @c IfaceMgr::closeSockets(AF_INET) before calling this function.
/// If there are any sockets open, the function may either throw an
/// exception or invoke an error handler on attempt to bind the new socket
/// to the same address and port.
///
/// @param port specifies port number (usually DHCP4_SERVER_PORT)
/// @param use_bcast configure sockets to support broadcast messages.
/// @param error_handler A pointer to an error handler function which is
......
src/lib/dhcp/tests/iface_mgr_unittest.cc
View file @ 68b6c2b5
......@@ -1457,9 +1457,7 @@ TEST_F(IfaceMgrTest, openSocket4ErrorHandler) {
ASSERT_TRUE(custom_packet_filter);
ASSERT_NO_THROW(ifacemgr.setPacketFilter(custom_packet_filter));
// Open socket on eth0. The openSockets4 should detect that this
// socket has been already open and an attempt to open another socket
// and bind to this address and port should fail.
// Open socket on eth0.
ASSERT_NO_THROW(ifacemgr.openSocket("eth0", IOAddress("10.0.0.1"),
DHCP4_SERVER_PORT));
......@@ -1467,6 +1465,9 @@ TEST_F(IfaceMgrTest, openSocket4ErrorHandler) {
// should be called when the IfaceMgr fails to open socket on eth0.
isc::dhcp::IfaceMgrErrorMsgCallback error_handler =
boost::bind(&IfaceMgrTest::ifaceMgrErrorHandler, this, _1);
// The openSockets4 should detect that there is another socket already
// open and bound to the same address and port. An attempt to open
// another socket and bind to this address and port should fail.
ASSERT_NO_THROW(ifacemgr.openSockets4(DHCP4_SERVER_PORT, true, error_handler));
// We expect that an error occured when we tried to open a socket on
// eth0, but the socket on eth1 should open just fine.
......@@ -1849,9 +1850,7 @@ TEST_F(IfaceMgrTest, openSocket6ErrorHandler) {
ASSERT_TRUE(filter);
ASSERT_NO_THROW(ifacemgr.setPacketFilter(filter));
// Open socket on eth0. The openSockets6 should detect that this
// socket has been already open and an attempt to open another socket
// and bind to this address and port should fail.
// Open socket on eth0.
ASSERT_NO_THROW(ifacemgr.openSocket("eth0",
IOAddress("fe80::3a60:77ff:fed5:cdef"),
DHCP6_SERVER_PORT));
......@@ -1860,12 +1859,10 @@ TEST_F(IfaceMgrTest, openSocket6ErrorHandler) {
// should be called when the IfaceMgr fails to open socket on eth0.
isc::dhcp::IfaceMgrErrorMsgCallback error_handler =
boost::bind(&IfaceMgrTest::ifaceMgrErrorHandler, this, _1);
// ASSERT_NO_THROW(ifacemgr.openSockets6(DHCP6_SERVER_PORT, error_handler));
try {
ifacemgr.openSockets6(DHCP6_SERVER_PORT, error_handler);
} catch (const Exception& ex) {
std::cout << ex.what() << std::endl;
}
// The openSockets6 should detect that a socket has been already
// opened on eth0 and an attempt to open another socket and bind to
// the same address and port should fail.
ASSERT_NO_THROW(ifacemgr.openSockets6(DHCP6_SERVER_PORT, error_handler));
// We expect that an error occured when we tried to open a socket on
// eth0, but the socket on eth1 should open just fine.
EXPECT_EQ(1, errors_count_);
......
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