1 /* $Id: ipx_mcast4.c,v 1.2 2003-12-08 22:55:27 btb Exp $ */
5 * "ipx driver" for IPv4 multicasting
16 #include <arpa/inet.h>
17 #include <netinet/in.h>
20 #include <sys/socket.h>
26 #include "ipx_mcast4.h"
30 #include "../../main/multi.h"
32 //#define IPX_MCAST4_DEBUG
34 extern unsigned char ipx_MyAddress[10];
36 #define UDP_BASEPORT 28342
37 #define PORTSHIFT_TOLERANCE 0x100
38 #define MAX_PACKETSIZE 8192
40 /* OUR port. Can be changed by "@X[+=]..." argument (X is the shift value)
42 static int baseport=UDP_BASEPORT;
44 static struct in_addr game_addr; // The game's multicast address
46 #define MSGHDR "IPX_mcast4: "
48 #ifdef IPX_MCAST4_DEBUG
49 static void msg(const char *fmt, ...)
53 fputs(MSGHDR, stdout);
63 #define FAIL(m...) do{ nm_messagebox("Error", 1, "Ok", ##m); return -1; } while (0)
65 #ifdef IPX_MCAST4_DEBUG
66 /* Dump raw form of IP address/port by fancy output to user
68 static void dumpraddr(unsigned char *a)
72 printf("[%u.%u.%u.%u]", a[0], a[1], a[2], a[3]);
73 port=(signed short)ntohs(*(unsigned short *)(a+4));
74 if (port) printf(":%+d",port);
77 /* Like dumpraddr() but for structure "sockaddr_in"
79 static void dumpaddr(struct sockaddr_in *sin)
82 unsigned char qhbuf[8];
84 memcpy(qhbuf + 0, &sin->sin_addr, 4);
85 ports = htons(((short)ntohs(sin->sin_port)) - UDP_BASEPORT);
86 memcpy(qhbuf + 4, &ports, 2);
91 // The multicast address for Descent 2 game announcements.
92 // TODO: Pick a better address for this
93 #define DESCENT2_ANNOUNCE_ADDR inet_addr("239.255.1.2")
95 /* Open the socket and subscribe to the multicast session */
96 static int ipx_mcast4_OpenSocket(ipx_socket_t *sk, int port)
100 struct sockaddr_in sin;
103 if((sk->fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
106 FAIL("socket() creation failed on port %d: %m", port);
110 sin.sin_family = AF_INET;
111 sin.sin_addr.s_addr = htonl(INADDR_ANY);
112 sin.sin_port = htons(baseport);
113 if (bind(sk->fd, (struct sockaddr *)&sin, sizeof(sin)))
116 msg("close() failed during error recovery: %m");
118 FAIL("bind() to UDP port %d failed: %m", baseport);
121 // Set the TTL so the packets can get out of the local network.
122 if(setsockopt(sk->fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
123 FAIL("setsockopt() failed to set TTL to 128");
125 // Disable multicast loopback
127 if(setsockopt(sk->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop)) < 0)
128 FAIL("setsockopt() failed to disable multicast loopback: %m");
130 // Subscribe to the game announcement address
131 memset(&mreq, 0, sizeof(mreq));
132 mreq.imr_multiaddr.s_addr = DESCENT2_ANNOUNCE_ADDR;
133 mreq.imr_interface.s_addr = INADDR_ANY;
134 if(setsockopt(sk->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
135 FAIL("setsockopt() failed to subscribe to the game announcement multicast group");
137 // We're not subscribed to a game address yet
138 game_addr.s_addr = 0;
144 static void ipx_mcast4_CloseSocket(ipx_socket_t *sk)
146 if(close(sk->fd) < 0)
151 static int ipx_mcast4_SendPacket(ipx_socket_t *sk, IPXPacket_t *IPXHeader, u_char *data, int dataLen)
153 struct sockaddr_in toaddr;
156 msg("SendPacket enter, dataLen=%d", dataLen);
158 if(dataLen < 0 || dataLen > MAX_PACKETSIZE)
161 toaddr.sin_family = AF_INET;
162 memcpy(&toaddr.sin_addr, IPXHeader->Destination.Node + 0, 4);
163 //toaddr.sin_port = htons(((short)ntohs(*(unsigned short *)(IPXHeader->Destination.Node + 4))) + UDP_BASEPORT);
164 // For now, just use the same port for everything
165 toaddr.sin_port = htons(UDP_BASEPORT);
167 // If it's the broadcast address, then we want to send it to the
168 // GAME ANNOUNCEMENT address.
169 // Data to be sent to the GAME has the destination already set by
170 // ipx_mcast4_SendGamePacket
171 if(toaddr.sin_addr.s_addr == INADDR_BROADCAST)
172 toaddr.sin_addr.s_addr = DESCENT2_ANNOUNCE_ADDR;
174 #ifdef IPX_MCAST4_DEBUG
175 printf(MSGHDR "sendto((%d),Node=[4] %02X %02X,Socket=%02X %02X,s_port=%u,",
177 IPXHeader->Destination.Node[4], IPXHeader->Destination.Node[5],
178 IPXHeader->Destination.Socket[0], IPXHeader->Destination.Socket[1],
179 ntohs(toaddr.sin_port));
184 i = sendto(sk->fd, data, dataLen, 0, (struct sockaddr *)&toaddr, sizeof(toaddr));
188 static int ipx_mcast4_ReceivePacket(ipx_socket_t *sk, char *outbuf, int outbufsize, struct ipx_recv_data *rd)
191 struct sockaddr_in fromaddr;
192 int fromaddrsize = sizeof(fromaddr);
194 if((size = recvfrom(sk->fd, outbuf, outbufsize, 0, (struct sockaddr*)&fromaddr, &fromaddrsize)) < 0)
197 #ifdef IPX_MCAST4_DEBUG
198 printf(MSGHDR "Got packet from ");
203 // We have the packet, now fill out the receive data.
204 memset(rd, 0, sizeof(*rd));
205 memcpy(rd->src_node, &fromaddr.sin_addr, 4);
206 // TODO: Include the port like in ipx_udp.c
212 /* Handle the netgame aux data
213 * Byte 0 is the protocol version number.
214 * Bytes 1-4 are the IPv4 multicast session to join, in network byte order.
216 static int ipx_mcast4_HandleNetgameAuxData(ipx_socket_t *sk, const u_char buf[NETGAME_AUX_SIZE])
218 // Extract the multicast session and subscribe to it. We should
219 // now be getting packets intended for the players of this game.
221 // Note that we stay subscribed to the game announcement session,
222 // so we can reply to game info requests
226 // Check the protocol version
227 if(buf[0] != IPX_MCAST4_VERSION)
229 FAIL("mcast4 protocol\nversion mismatch!\nGame version is %02x,\nour version is %02x", buf[0], IPX_MCAST4_VERSION);
232 // Get the multicast session
233 memcpy(&game_addr, buf + 1, sizeof(game_addr));
235 #ifdef IPX_MCAST4_DEBUG
237 struct sockaddr_in tmpaddr;
238 tmpaddr.sin_addr = game_addr;
239 tmpaddr.sin_port = 0;
241 printf("Handling netgame aux data: Subscribing to ");
247 // Set the TTL so the packets can get out of the local network.
248 if(setsockopt(sk->fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
249 FAIL("setsockopt() failed to set TTL to 128");
251 memset(&mreq, 0, sizeof(mreq));
252 mreq.imr_multiaddr = game_addr;
253 mreq.imr_interface.s_addr = INADDR_ANY;
255 if(setsockopt(sk->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
256 FAIL("setsockopt() failed to subscribe to the game group");
261 /* Create the netgame aux data.
262 * Byte 0 is the protcol version number.
263 * Bytes 1-4 hold the IPv4 multicast session for the game.
265 static void ipx_mcast4_InitNetgameAuxData(ipx_socket_t *sk, u_char buf[NETGAME_AUX_SIZE])
267 Assert(game_addr.s_addr == 0);
269 // The first byte is the version number
270 buf[0] = IPX_MCAST4_VERSION;
272 // Generate a random session
273 game_addr = inet_makeaddr(239*256 + 255, d_rand() % 0xFFFF);
274 memcpy(buf + 1, &game_addr, sizeof(game_addr));
276 // Since we're obviously the hosting machine, subscribe to this address
277 ipx_mcast4_HandleNetgameAuxData(sk, buf);
280 static void ipx_mcast4_HandleLeaveGame(ipx_socket_t *sk)
282 // We left the game, so unsubscribe from its multicast session
285 Assert(game_addr.s_addr != 0);
287 #ifdef IPX_MCAST4_DEBUG
288 printf("Unsubscribing from game's multicast group: ");
289 dumpraddr(&game_addr.s_addr);
293 mreq.imr_multiaddr = game_addr;
294 mreq.imr_interface.s_addr = INADDR_ANY;
295 if(setsockopt(sk->fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
296 msg("setsockopt() failed unsubscribing from previous group!");
297 game_addr.s_addr = 0;
300 // Send a packet to every member of the game. We can just multicast it here.
301 static int ipx_mcast4_SendGamePacket(ipx_socket_t *sk, ubyte *data, int dataLen)
303 struct sockaddr_in toaddr;
306 memset(&toaddr, 0, sizeof(toaddr));
307 toaddr.sin_addr = game_addr;
308 toaddr.sin_port = htons(UDP_BASEPORT);
310 msg("ipx_mcast4_SendGamePacket");
312 i = sendto(sk->fd, data, dataLen, 0, (struct sockaddr *)&toaddr, sizeof(toaddr));
317 // Pull this in from ipx_udp.c since it's the same for us.
318 extern int ipx_udp_GetMyAddress();
320 struct ipx_driver ipx_mcast4 = {
321 ipx_udp_GetMyAddress,
322 ipx_mcast4_OpenSocket,
323 ipx_mcast4_CloseSocket,
324 ipx_mcast4_SendPacket,
325 ipx_mcast4_ReceivePacket,
326 ipx_general_PacketReady,
327 ipx_mcast4_InitNetgameAuxData,
328 ipx_mcast4_HandleNetgameAuxData,
329 ipx_mcast4_HandleLeaveGame,
330 ipx_mcast4_SendGamePacket