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Use non-sACN multicast IP by default; add parameter to use sACN multicast #307

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Use non-sACN multicast IP by default; add parameter to use sACN multicast #307

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a7fcaab
Use non-sACN multicast IP by default; add parameter to use sACN multi…
GinjaNinja32 Mar 20, 2026
20a7ae6
Change bool to enum class
GinjaNinja32 Mar 21, 2026
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46 changes: 33 additions & 13 deletions src/io/network/udpSocket.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,32 @@ namespace sp {
namespace io {
namespace network {

int getMulticastIPv4(UdpMulticastMode mode, int group_nr) {
switch (mode) {
case UdpMulticastMode::SACN: // 239.255.gh.gl
return htonl((239 << 24) | (255 << 16) | (group_nr));
default:
case UdpMulticastMode::Default: // 239.192.gh.gl
return htonl((239 << 24) | (192 << 16) | (group_nr));
}
}
void setMulticastIPv6(unsigned char* address, UdpMulticastMode mode, int group_nr) {
address[14] = group_nr >> 8;
address[15] = group_nr;

switch (mode) {
case UdpMulticastMode::SACN: // FF18::8300:GHGL
address[0] = 0xff;
address[1] = 0x18;
address[12] = 0x83;
break;
default:
case UdpMulticastMode::Default: // FF08::GHGL
address[0] = 0xff;
address[1] = 0x08;
}
}


UdpSocket::UdpSocket()
{
Expand Down Expand Up @@ -121,7 +147,7 @@ bool UdpSocket::joinMulticast(int group_nr)
memcpy(&server_addr, addr_info.addr.data(), addr_info.addr.size());

struct ip_mreq mreq;
mreq.imr_multiaddr.s_addr = htonl((239 << 24) | (255 << 16) | (group_nr));
mreq.imr_multiaddr.s_addr = getMulticastIPv4(UdpMulticastMode::Default, group_nr);
mreq.imr_interface.s_addr = server_addr.sin_addr.s_addr;

success = success && ::setsockopt(handle, IPPROTO_IP, IP_ADD_MEMBERSHIP, reinterpret_cast<const char*>(&mreq), sizeof(mreq)) == 0;
Expand All @@ -133,10 +159,7 @@ bool UdpSocket::joinMulticast(int group_nr)
struct ipv6_mreq mreq;
memset(&mreq, 0, sizeof(mreq));
mreq.ipv6mr_interface = 0;
mreq.ipv6mr_multiaddr.s6_addr[0] = 0xff;
mreq.ipv6mr_multiaddr.s6_addr[1] = 0x08;
mreq.ipv6mr_multiaddr.s6_addr[14] = group_nr >> 8;
mreq.ipv6mr_multiaddr.s6_addr[15] = group_nr;
setMulticastIPv6(mreq.ipv6mr_multiaddr.s6_addr, UdpMulticastMode::Default, group_nr);

success = ::setsockopt(handle, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, reinterpret_cast<const char*>(&mreq), sizeof(mreq)) == 0;
}
Expand Down Expand Up @@ -282,7 +305,7 @@ bool UdpSocket::receive(DataBuffer& buffer, Address& address, int& port)
return received_size > 0;
}

bool UdpSocket::sendMulticast(const void* data, size_t size, int group_nr, int port)
bool UdpSocket::sendMulticast(const void* data, size_t size, int group_nr, int port, UdpMulticastMode mode)
{
if (handle == INVALID_SOCKET)
{
Expand All @@ -300,7 +323,7 @@ bool UdpSocket::sendMulticast(const void* data, size_t size, int group_nr, int p
::setsockopt(handle, IPPROTO_IP, IP_MULTICAST_IF, reinterpret_cast<const char*>(&server_addr.sin_addr), sizeof(server_addr.sin_addr));

memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_addr.s_addr = htonl((239 << 24) | (192 << 16) | (group_nr));
server_addr.sin_addr.s_addr = getMulticastIPv4(mode, group_nr);

server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(port);
Expand All @@ -317,10 +340,7 @@ bool UdpSocket::sendMulticast(const void* data, size_t size, int group_nr, int p
::setsockopt(handle, IPPROTO_IPV6, IPV6_MULTICAST_IF, reinterpret_cast<const char*>(&server_addr.sin6_addr), sizeof(server_addr.sin6_addr));

memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin6_addr.s6_addr[0] = 0xff;
server_addr.sin6_addr.s6_addr[1] = 0x08;
server_addr.sin6_addr.s6_addr[14] = group_nr >> 8;
server_addr.sin6_addr.s6_addr[15] = group_nr;
setMulticastIPv6(server_addr.sin6_addr.s6_addr, mode, group_nr);
server_addr.sin6_family = AF_INET6;
server_addr.sin6_port = htons(port);

Expand All @@ -332,9 +352,9 @@ bool UdpSocket::sendMulticast(const void* data, size_t size, int group_nr, int p
return success;
}

bool UdpSocket::sendMulticast(const DataBuffer& buffer, int group_nr, int port)
bool UdpSocket::sendMulticast(const DataBuffer& buffer, int group_nr, int port, UdpMulticastMode mode)
{
return sendMulticast(buffer.getData(), buffer.getDataSize(), group_nr, port);
return sendMulticast(buffer.getData(), buffer.getDataSize(), group_nr, port, mode);
}

bool UdpSocket::sendBroadcast(const void* data, size_t size, int port)
Expand Down
8 changes: 6 additions & 2 deletions src/io/network/udpSocket.h
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,10 @@ namespace sp {
namespace io {
namespace network {

enum class UdpMulticastMode {
Default, // Default SP multicast; 239.192.hh.ll or FF08::hhll
SACN, // sACN multicast; 239.255.hh.ll or FF18::8300:hhll
};

class UdpSocket : public SocketBase
{
Expand All @@ -29,8 +33,8 @@ class UdpSocket : public SocketBase
bool send(const DataBuffer& buffer, const Address& address, int port);
bool receive(DataBuffer& buffer, Address& address, int& port);

bool sendMulticast(const void* data, size_t size, int group_nr, int port);
bool sendMulticast(const DataBuffer& buffer, int group_nr, int port);
bool sendMulticast(const void* data, size_t size, int group_nr, int port, UdpMulticastMode mode = UdpMulticastMode::Default);
bool sendMulticast(const DataBuffer& buffer, int group_nr, int port, UdpMulticastMode mode = UdpMulticastMode::Default);

bool sendBroadcast(const void* data, size_t size, int port);
bool sendBroadcast(const DataBuffer& buffer, int port);
Expand Down
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