1 /* $Id: ipx_mcast4.c,v 1.2 2003-10-14 20:48:15 btb Exp $ */
5 * "ipx driver" for IPv4 multicasting
24 #include "ipx_mcast4.h"
27 #include "../../main/multi.h"
28 #include "../../main/newmenu.h"
30 //#define IPX_MCAST4_DEBUG
32 extern unsigned char ipx_MyAddress[10];
34 #define UDP_BASEPORT 28342
35 #define PORTSHIFT_TOLERANCE 0x100
36 #define MAX_PACKETSIZE 8192
38 /* OUR port. Can be changed by "@X[+=]..." argument (X is the shift value)
40 static int baseport=UDP_BASEPORT;
42 static struct in_addr game_addr; // The game's multicast address
44 #define MSGHDR "IPX_mcast4: "
46 #ifdef IPX_MCAST4_DEBUG
47 static void msg(const char *fmt, ...)
51 fputs(MSGHDR, stdout);
61 #define FAIL(m...) do{ nm_messagebox("Error", 1, "Ok", ##m); return -1; } while (0)
63 #ifdef IPX_MCAST4_DEBUG
64 /* Dump raw form of IP address/port by fancy output to user
66 static void dumpraddr(unsigned char *a)
70 printf("[%u.%u.%u.%u]", a[0], a[1], a[2], a[3]);
71 port=(signed short)ntohs(*(unsigned short *)(a+4));
72 if (port) printf(":%+d",port);
75 /* Like dumpraddr() but for structure "sockaddr_in"
77 static void dumpaddr(struct sockaddr_in *sin)
80 unsigned char qhbuf[8];
82 memcpy(qhbuf + 0, &sin->sin_addr, 4);
83 ports = htons(((short)ntohs(sin->sin_port)) - UDP_BASEPORT);
84 memcpy(qhbuf + 4, &ports, 2);
89 // The multicast address for Descent 2 game announcements.
90 // TODO: Pick a better address for this
91 #define DESCENT2_ANNOUNCE_ADDR inet_addr("239.255.1.2")
93 /* Open the socket and subscribe to the multicast session */
94 static int ipx_mcast4_OpenSocket(ipx_socket_t *sk, int port)
98 struct sockaddr_in sin;
101 if((sk->fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
104 FAIL("socket() creation failed on port %d: %m", port);
108 sin.sin_family = AF_INET;
109 sin.sin_addr.s_addr = htonl(INADDR_ANY);
110 sin.sin_port = htons(baseport);
111 if (bind(sk->fd, (struct sockaddr *)&sin, sizeof(sin)))
113 if (closesocket(sk->fd))
114 msg("close() failed during error recovery: %m");
116 FAIL("bind() to UDP port %d failed: %m", baseport);
119 // Set the TTL so the packets can get out of the local network.
120 if(setsockopt(sk->fd, IPPROTO_IP, IP_MULTICAST_TTL, (const void*)&ttl, sizeof(ttl)) < 0)
121 FAIL("setsockopt() failed to set TTL to 128");
123 // Disable multicast loopback
125 if(setsockopt(sk->fd, IPPROTO_IP, IP_MULTICAST_LOOP, (const void*)&loop, sizeof(loop)) < 0)
126 FAIL("setsockopt() failed to disable multicast loopback: %m");
128 // Subscribe to the game announcement address
129 memset(&mreq, 0, sizeof(mreq));
130 mreq.imr_multiaddr.s_addr = DESCENT2_ANNOUNCE_ADDR;
131 mreq.imr_interface.s_addr = INADDR_ANY;
132 if(setsockopt(sk->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (const void*)&mreq, sizeof(mreq)) < 0)
133 FAIL("setsockopt() failed to subscribe to the game announcement multicast group");
135 // We're not subscribed to a game address yet
136 game_addr.s_addr = 0;
142 static void ipx_mcast4_CloseSocket(ipx_socket_t *sk)
144 if(closesocket(sk->fd) < 0)
149 static int ipx_mcast4_SendPacket(ipx_socket_t *sk, IPXPacket_t *IPXHeader, u_char *data, int dataLen)
151 struct sockaddr_in toaddr;
154 msg("SendPacket enter, dataLen=%d", dataLen);
156 if(dataLen < 0 || dataLen > MAX_PACKETSIZE)
159 toaddr.sin_family = AF_INET;
160 memcpy(&toaddr.sin_addr, IPXHeader->Destination.Node + 0, 4);
161 //toaddr.sin_port = htons(((short)ntohs(*(unsigned short *)(IPXHeader->Destination.Node + 4))) + UDP_BASEPORT);
162 // For now, just use the same port for everything
163 toaddr.sin_port = htons(UDP_BASEPORT);
165 // If it's the broadcast address, then we want to send it to the
166 // GAME ANNOUNCEMENT address.
167 // Data to be sent to the GAME has the destination already set by
168 // ipx_mcast4_SendGamePacket
169 if(toaddr.sin_addr.s_addr == INADDR_BROADCAST)
170 toaddr.sin_addr.s_addr = DESCENT2_ANNOUNCE_ADDR;
172 #ifdef IPX_MCAST4_DEBUG
173 printf(MSGHDR "sendto((%d),Node=[4] %02X %02X,Socket=%02X %02X,s_port=%u,",
175 IPXHeader->Destination.Node[4], IPXHeader->Destination.Node[5],
176 IPXHeader->Destination.Socket[0], IPXHeader->Destination.Socket[1],
177 ntohs(toaddr.sin_port));
182 i = sendto(sk->fd, data, dataLen, 0, (struct sockaddr *)&toaddr, sizeof(toaddr));
186 static int ipx_mcast4_ReceivePacket(ipx_socket_t *sk, char *outbuf, int outbufsize, struct ipx_recv_data *rd)
189 struct sockaddr_in fromaddr;
190 int fromaddrsize = sizeof(fromaddr);
192 if((size = recvfrom(sk->fd, outbuf, outbufsize, 0, (struct sockaddr*)&fromaddr, &fromaddrsize)) < 0)
195 #ifdef IPX_MCAST4_DEBUG
196 printf(MSGHDR "Got packet from ");
201 // We have the packet, now fill out the receive data.
202 memset(rd, 0, sizeof(*rd));
203 memcpy(rd->src_node, &fromaddr.sin_addr, 4);
204 // TODO: Include the port like in ipx_udp.c
210 /* Handle the netgame aux data
211 * Byte 0 is the protocol version number.
212 * Bytes 1-4 are the IPv4 multicast session to join, in network byte order.
214 static int ipx_mcast4_HandleNetgameAuxData(ipx_socket_t *sk, const u_char buf[NETGAME_AUX_SIZE])
216 // Extract the multicast session and subscribe to it. We should
217 // now be getting packets intended for the players of this game.
219 // Note that we stay subscribed to the game announcement session,
220 // so we can reply to game info requests
224 // Check the protocol version
225 if(buf[0] != IPX_MCAST4_VERSION)
227 FAIL("mcast4 protocol\nversion mismatch!\nGame version is %02x,\nour version is %02x", buf[0], IPX_MCAST4_VERSION);
230 // Get the multicast session
231 memcpy(&game_addr, buf + 1, sizeof(game_addr));
233 #ifdef IPX_MCAST4_DEBUG
235 struct sockaddr_in tmpaddr;
236 tmpaddr.sin_addr = game_addr;
237 tmpaddr.sin_port = 0;
239 printf("Handling netgame aux data: Subscribing to ");
245 // Set the TTL so the packets can get out of the local network.
246 if(setsockopt(sk->fd, IPPROTO_IP, IP_MULTICAST_TTL, (const void*)&ttl, sizeof(ttl)) < 0)
247 FAIL("setsockopt() failed to set TTL to 128");
249 memset(&mreq, 0, sizeof(mreq));
250 mreq.imr_multiaddr = game_addr;
251 mreq.imr_interface.s_addr = INADDR_ANY;
253 if(setsockopt(sk->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (const void*)&mreq, sizeof(mreq)) < 0)
254 FAIL("setsockopt() failed to subscribe to the game group");
259 /* Create the netgame aux data.
260 * Byte 0 is the protcol version number.
261 * Bytes 1-4 hold the IPv4 multicast session for the game.
263 static void ipx_mcast4_InitNetgameAuxData(ipx_socket_t *sk, u_char buf[NETGAME_AUX_SIZE])
266 Assert(game_addr.s_addr == 0);
268 // The first byte is the version number
269 buf[0] = IPX_MCAST4_VERSION;
271 // Generate a random session
272 // game_addr = inet_makeaddr(239*256 + 255, d_rand() % 0xFFFF);
273 sprintf(addr, "%i.%i.%i.%i", 239, 255, d_rand() % 0xFF, d_rand() % 0xFF);
274 game_addr.s_addr = inet_addr(addr);
275 memcpy(buf + 1, &game_addr, sizeof(game_addr));
277 // Since we're obviously the hosting machine, subscribe to this address
278 ipx_mcast4_HandleNetgameAuxData(sk, buf);
281 static void ipx_mcast4_HandleLeaveGame(ipx_socket_t *sk)
283 // We left the game, so unsubscribe from its multicast session
286 Assert(game_addr.s_addr != 0);
288 #ifdef IPX_MCAST4_DEBUG
289 printf("Unsubscribing from game's multicast group: ");
290 dumpraddr(&game_addr.s_addr);
294 mreq.imr_multiaddr = game_addr;
295 mreq.imr_interface.s_addr = INADDR_ANY;
296 if(setsockopt(sk->fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, (const void*)&mreq, sizeof(mreq)) < 0)
297 msg("setsockopt() failed unsubscribing from previous group!");
298 game_addr.s_addr = 0;
301 // Send a packet to every member of the game. We can just multicast it here.
302 static int ipx_mcast4_SendGamePacket(ipx_socket_t *sk, ubyte *data, int dataLen)
304 struct sockaddr_in toaddr;
307 memset(&toaddr, 0, sizeof(toaddr));
308 toaddr.sin_family = AF_INET;
309 toaddr.sin_addr = game_addr;
310 toaddr.sin_port = htons(UDP_BASEPORT);
312 msg("ipx_mcast4_SendGamePacket");
314 i = sendto(sk->fd, data, dataLen, 0, (struct sockaddr *)&toaddr, sizeof(toaddr));
319 // Pull this in from ipx_udp.c since it's the same for us.
320 extern int ipx_udp_GetMyAddress();
322 struct ipx_driver ipx_mcast4 = {
323 ipx_udp_GetMyAddress,
324 ipx_mcast4_OpenSocket,
325 ipx_mcast4_CloseSocket,
326 ipx_mcast4_SendPacket,
327 ipx_mcast4_ReceivePacket,
328 ipx_general_PacketReady,
329 ipx_mcast4_InitNetgameAuxData,
330 ipx_mcast4_HandleNetgameAuxData,
331 ipx_mcast4_HandleLeaveGame,
332 ipx_mcast4_SendGamePacket