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-rw-r--r--pkg/tcpip/network/ipv4/ipv4.go4
-rw-r--r--pkg/tcpip/network/ipv6/ipv6.go4
-rw-r--r--pkg/tcpip/stack/route.go10
-rw-r--r--test/syscalls/linux/socket_ipv4_udp_unbound_external_networking.cc129
4 files changed, 145 insertions, 2 deletions
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index da07a39e5..44b1d5b9b 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -215,7 +215,9 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, hdr buffer.Prepen
views[0] = hdr.View()
views = append(views, payload.Views()...)
vv := buffer.NewVectorisedView(len(views[0])+payload.Size(), views)
- e.HandlePacket(r, vv)
+ loopedR := r.MakeLoopedRoute()
+ e.HandlePacket(&loopedR, vv)
+ loopedR.Release()
}
if loop&stack.PacketOut == 0 {
return nil
diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go
index 4b8cd496b..bcae98e1f 100644
--- a/pkg/tcpip/network/ipv6/ipv6.go
+++ b/pkg/tcpip/network/ipv6/ipv6.go
@@ -108,7 +108,9 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, hdr buffer.Prepen
views[0] = hdr.View()
views = append(views, payload.Views()...)
vv := buffer.NewVectorisedView(len(views[0])+payload.Size(), views)
- e.HandlePacket(r, vv)
+ loopedR := r.MakeLoopedRoute()
+ e.HandlePacket(&loopedR, vv)
+ loopedR.Release()
}
if loop&stack.PacketOut == 0 {
return nil
diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go
index 3d4c282a9..55ed02479 100644
--- a/pkg/tcpip/stack/route.go
+++ b/pkg/tcpip/stack/route.go
@@ -187,3 +187,13 @@ func (r *Route) Clone() Route {
r.ref.incRef()
return *r
}
+
+// MakeLoopedRoute duplicates the given route and tweaks it in case of multicast.
+func (r *Route) MakeLoopedRoute() Route {
+ l := r.Clone()
+ if header.IsV4MulticastAddress(r.RemoteAddress) || header.IsV6MulticastAddress(r.RemoteAddress) {
+ l.RemoteAddress, l.LocalAddress = l.LocalAddress, l.RemoteAddress
+ l.RemoteLinkAddress = l.LocalLinkAddress
+ }
+ return l
+}
diff --git a/test/syscalls/linux/socket_ipv4_udp_unbound_external_networking.cc b/test/syscalls/linux/socket_ipv4_udp_unbound_external_networking.cc
index 53dcd58cd..6b92e05aa 100644
--- a/test/syscalls/linux/socket_ipv4_udp_unbound_external_networking.cc
+++ b/test/syscalls/linux/socket_ipv4_udp_unbound_external_networking.cc
@@ -559,5 +559,134 @@ TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
EXPECT_EQ(0, memcmp(send_buf, recv_buf, sizeof(send_buf)));
}
+// Check that two sockets can join the same multicast group at the same time,
+// and both will receive data on it.
+TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest, TestSendMulticastToTwo) {
+ auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
+ std::unique_ptr<FileDescriptor> receivers[2] = {
+ ASSERT_NO_ERRNO_AND_VALUE(NewSocket()),
+ ASSERT_NO_ERRNO_AND_VALUE(NewSocket())};
+
+ ip_mreq group = {};
+ group.imr_multiaddr.s_addr = inet_addr(kMulticastAddress);
+ auto receiver_addr = V4Any();
+ int bound_port = 0;
+ for (auto& receiver : receivers) {
+ ASSERT_THAT(setsockopt(receiver->get(), SOL_SOCKET, SO_REUSEPORT,
+ &kSockOptOn, sizeof(kSockOptOn)),
+ SyscallSucceeds());
+ // Bind the receiver to the v4 any address to ensure that we can receive the
+ // multicast packet.
+ ASSERT_THAT(
+ bind(receiver->get(), reinterpret_cast<sockaddr*>(&receiver_addr.addr),
+ receiver_addr.addr_len),
+ SyscallSucceeds());
+ socklen_t receiver_addr_len = receiver_addr.addr_len;
+ ASSERT_THAT(getsockname(receiver->get(),
+ reinterpret_cast<sockaddr*>(&receiver_addr.addr),
+ &receiver_addr_len),
+ SyscallSucceeds());
+ EXPECT_EQ(receiver_addr_len, receiver_addr.addr_len);
+ // On the first iteration, save the port we are bound to. On the second
+ // iteration, verify the port is the same as the one from the first
+ // iteration. In other words, both sockets listen on the same port.
+ if (bound_port == 0) {
+ bound_port =
+ reinterpret_cast<sockaddr_in*>(&receiver_addr.addr)->sin_port;
+ } else {
+ EXPECT_EQ(bound_port,
+ reinterpret_cast<sockaddr_in*>(&receiver_addr.addr)->sin_port);
+ }
+
+ // Register to receive multicast packets.
+ ASSERT_THAT(setsockopt(receiver->get(), IPPROTO_IP, IP_ADD_MEMBERSHIP,
+ &group, sizeof(group)),
+ SyscallSucceeds());
+ }
+
+ // Send a multicast packet to the group and verify both receivers get it.
+ auto send_addr = V4Multicast();
+ reinterpret_cast<sockaddr_in*>(&send_addr.addr)->sin_port = bound_port;
+ char send_buf[200];
+ RandomizeBuffer(send_buf, sizeof(send_buf));
+ ASSERT_THAT(RetryEINTR(sendto)(sender->get(), send_buf, sizeof(send_buf), 0,
+ reinterpret_cast<sockaddr*>(&send_addr.addr),
+ send_addr.addr_len),
+ SyscallSucceedsWithValue(sizeof(send_buf)));
+ for (auto& receiver : receivers) {
+ char recv_buf[sizeof(send_buf)] = {};
+ ASSERT_THAT(
+ RetryEINTR(recv)(receiver->get(), recv_buf, sizeof(recv_buf), 0),
+ SyscallSucceedsWithValue(sizeof(recv_buf)));
+ EXPECT_EQ(0, memcmp(send_buf, recv_buf, sizeof(send_buf)));
+ }
+}
+
+// Check that when receiving a looped-back multicast packet, its source address
+// is not a multicast address.
+TEST_P(IPv4UDPUnboundExternalNetworkingSocketTest,
+ IpMulticastLoopbackFromAddr) {
+ auto sender = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
+ auto receiver = ASSERT_NO_ERRNO_AND_VALUE(NewSocket());
+
+ auto receiver_addr = V4Any();
+ ASSERT_THAT(
+ bind(receiver->get(), reinterpret_cast<sockaddr*>(&receiver_addr.addr),
+ receiver_addr.addr_len),
+ SyscallSucceeds());
+ socklen_t receiver_addr_len = receiver_addr.addr_len;
+ ASSERT_THAT(getsockname(receiver->get(),
+ reinterpret_cast<sockaddr*>(&receiver_addr.addr),
+ &receiver_addr_len),
+ SyscallSucceeds());
+ EXPECT_EQ(receiver_addr_len, receiver_addr.addr_len);
+ int receiver_port =
+ reinterpret_cast<sockaddr_in*>(&receiver_addr.addr)->sin_port;
+
+ ip_mreq group = {};
+ group.imr_multiaddr.s_addr = inet_addr(kMulticastAddress);
+ ASSERT_THAT(setsockopt(receiver->get(), IPPROTO_IP, IP_ADD_MEMBERSHIP, &group,
+ sizeof(group)),
+ SyscallSucceeds());
+
+ // Connect to the multicast address. This binds us to the outgoing interface
+ // and allows us to get its IP (to be compared against the src-IP on the
+ // receiver side).
+ auto sendto_addr = V4Multicast();
+ reinterpret_cast<sockaddr_in*>(&sendto_addr.addr)->sin_port = receiver_port;
+ ASSERT_THAT(RetryEINTR(connect)(
+ sender->get(), reinterpret_cast<sockaddr*>(&sendto_addr.addr),
+ sendto_addr.addr_len),
+ SyscallSucceeds());
+ TestAddress sender_addr("");
+ ASSERT_THAT(
+ getsockname(sender->get(), reinterpret_cast<sockaddr*>(&sender_addr.addr),
+ &sender_addr.addr_len),
+ SyscallSucceeds());
+ ASSERT_EQ(sizeof(struct sockaddr_in), sender_addr.addr_len);
+ sockaddr_in* sender_addr_in =
+ reinterpret_cast<sockaddr_in*>(&sender_addr.addr);
+
+ // Send a multicast packet.
+ char send_buf[4] = {};
+ ASSERT_THAT(RetryEINTR(send)(sender->get(), send_buf, sizeof(send_buf), 0),
+ SyscallSucceedsWithValue(sizeof(send_buf)));
+
+ // Receive a multicast packet.
+ char recv_buf[sizeof(send_buf)] = {};
+ TestAddress src_addr("");
+ ASSERT_THAT(
+ RetryEINTR(recvfrom)(receiver->get(), recv_buf, sizeof(recv_buf), 0,
+ reinterpret_cast<sockaddr*>(&src_addr.addr),
+ &src_addr.addr_len),
+ SyscallSucceedsWithValue(sizeof(recv_buf)));
+ ASSERT_EQ(sizeof(struct sockaddr_in), src_addr.addr_len);
+ sockaddr_in* src_addr_in = reinterpret_cast<sockaddr_in*>(&src_addr.addr);
+
+ // Verify that the received source IP:port matches the sender one.
+ EXPECT_EQ(sender_addr_in->sin_port, src_addr_in->sin_port);
+ EXPECT_EQ(sender_addr_in->sin_addr.s_addr, src_addr_in->sin_addr.s_addr);
+}
+
} // namespace testing
} // namespace gvisor
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-08 02:57:59 +0000