1 /* $NetBSD: server.c,v 1.9 2021/10/29 11:40:23 nia Exp $ */ 2 /* 3 * Copyright (c) 1983-2003, Regents of the University of California. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions are 8 * met: 9 * 10 * + Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * + Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * + Neither the name of the University of California, San Francisco nor 16 * the names of its contributors may be used to endorse or promote 17 * products derived from this software without specific prior written 18 * permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 21 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 23 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __RCSID("$NetBSD: server.c,v 1.9 2021/10/29 11:40:23 nia Exp $"); 35 36 #include <sys/param.h> 37 #include <sys/stat.h> 38 #include <sys/time.h> 39 #include <sys/poll.h> 40 #include <ctype.h> 41 #include <err.h> 42 #include <errno.h> 43 #include <signal.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <unistd.h> 47 #include <assert.h> 48 #include <ifaddrs.h> 49 50 #include "hunt_common.h" 51 #include "pathnames.h" 52 #include "hunt_private.h" 53 54 #ifdef INTERNET 55 56 /* 57 * Code for finding and talking to hunt daemons. 58 */ 59 60 static struct sockaddr_in *daemons; 61 static unsigned int numdaemons, maxdaemons; 62 63 static struct sockaddr_in *broadcastaddrs; 64 static int numbroadcastaddrs; 65 66 static bool initial = true; 67 static struct in_addr local_address; 68 static const char *explicit_host; 69 static uint16_t port; 70 71 void 72 serverlist_setup(const char *explicit_host_arg, uint16_t port_arg) 73 { 74 char local_name[MAXHOSTNAMELEN + 1]; 75 struct hostent *hp; 76 77 if (gethostname(local_name, sizeof(local_name)) < 0) { 78 leavex(1, "Sorry, I have no hostname."); 79 } 80 local_name[sizeof(local_name) - 1] = '\0'; 81 if ((hp = gethostbyname(local_name)) == NULL) { 82 leavex(1, "Can't find myself."); 83 } 84 memcpy(&local_address, hp->h_addr, sizeof(local_address)); 85 86 numdaemons = 0; 87 maxdaemons = 20; 88 daemons = NULL; 89 if (reallocarr(&daemons, maxdaemons, sizeof(daemons[0])) != 0) 90 leavex(1, "Out of memory."); 91 92 if (explicit_host_arg) { 93 explicit_host = explicit_host_arg; 94 } 95 port = port_arg; 96 } 97 98 static void 99 add_daemon_addr(const struct sockaddr_storage *addr, socklen_t addrlen, 100 uint16_t port_num) 101 { 102 const struct sockaddr_in *sin; 103 104 if (addr->ss_family != AF_INET) { 105 return; 106 } 107 assert(addrlen == sizeof(struct sockaddr_in)); 108 sin = (const struct sockaddr_in *)addr; 109 110 assert(numdaemons <= maxdaemons); 111 if (numdaemons == maxdaemons) { 112 maxdaemons += 20; 113 if (reallocarr(&daemons, maxdaemons, sizeof(daemons[0])) != 0) 114 leave(1, "realloc"); 115 } 116 117 /* 118 * Note that we do *not* convert from network to host 119 * order since the port number we were sent *should* 120 * already be in network order. 121 * 122 * The result may be either the port number for the hunt 123 * socket or the port number for the stats socket... or the 124 * number of players connected and not a port number at all, 125 * depending on the packet type. 126 * 127 * For now at least it is ok to stuff it in here, because the 128 * usage of the various different packet types and the 129 * persistence of the results vs. the program exiting does not 130 * cause us to get confused. If the game is made more 131 * self-contained in the future we'll need to be more careful 132 * about this, especially if we make the caching of results 133 * less scattershot. 134 */ 135 daemons[numdaemons] = *sin; 136 daemons[numdaemons].sin_port = port_num; 137 numdaemons++; 138 } 139 140 static bool 141 have_daemon_addr(const struct sockaddr_storage *addr, socklen_t addrlen) 142 { 143 unsigned j; 144 const struct sockaddr_in *sin; 145 146 if (addr->ss_family != AF_INET) { 147 return false; 148 } 149 assert(addrlen == sizeof(struct sockaddr_in)); 150 sin = (const struct sockaddr_in *)addr; 151 152 for (j = 0; j < numdaemons; j++) { 153 if (sin->sin_addr.s_addr == daemons[j].sin_addr.s_addr) { 154 return true; 155 } 156 } 157 return false; 158 } 159 160 static void 161 getbroadcastaddrs(void) 162 { 163 unsigned num, i; 164 struct ifaddrs *ifp, *ip; 165 166 broadcastaddrs = NULL; 167 numbroadcastaddrs = 0; 168 169 if (getifaddrs(&ifp) < 0) { 170 return; 171 } 172 173 num = 0; 174 for (ip = ifp; ip; ip = ip->ifa_next) { 175 if ((ip->ifa_addr->sa_family == AF_INET) && 176 (ip->ifa_flags & IFF_BROADCAST)) { 177 num++; 178 } 179 } 180 181 broadcastaddrs = NULL; 182 if (reallocarr(&broadcastaddrs, num, sizeof(broadcastaddrs[0])) != 0) 183 leavex(1, "Out of memory"); 184 185 i = 0; 186 for (ip = ifp; ip; ip = ip->ifa_next) { 187 if ((ip->ifa_addr->sa_family == AF_INET) && 188 (ip->ifa_flags & IFF_BROADCAST)) { 189 memcpy(&broadcastaddrs[i], ip->ifa_broadaddr, 190 sizeof(broadcastaddrs[i])); 191 i++; 192 } 193 } 194 assert(i == num); 195 numbroadcastaddrs = num; 196 197 freeifaddrs(ifp); 198 } 199 200 static void 201 send_messages(int contactsock, unsigned short msg) 202 { 203 struct sockaddr_in contactaddr; 204 struct hostent *hp; 205 uint16_t wiremsg; 206 int option; 207 int i; 208 209 memset(&contactaddr, 0, sizeof(contactaddr)); 210 contactaddr.sin_family = SOCK_FAMILY; 211 contactaddr.sin_port = htons(port); 212 213 if (explicit_host != NULL) { /* explicit host given */ 214 hp = gethostbyname(explicit_host); 215 if (hp == NULL) { 216 leavex(1, "%s: Unknown host", explicit_host); 217 } 218 memcpy(&contactaddr.sin_addr, hp->h_addr, 219 sizeof(contactaddr.sin_addr)); 220 wiremsg = htons(msg); 221 (void) sendto(contactsock, &wiremsg, sizeof(wiremsg), 0, 222 (struct sockaddr *)&contactaddr, 223 sizeof(contactaddr)); 224 return; 225 } 226 227 if (!initial) { 228 /* favor host of previous session by contacting it first */ 229 contactaddr.sin_addr = Daemon.sin_addr; 230 231 /* Must be playing! */ 232 assert(msg == C_PLAYER); 233 wiremsg = htons(msg); 234 235 (void) sendto(contactsock, &wiremsg, sizeof(wiremsg), 0, 236 (struct sockaddr *)&contactaddr, sizeof(contactaddr)); 237 } 238 239 if (initial) { 240 getbroadcastaddrs(); 241 } 242 243 #ifdef SO_BROADCAST 244 /* Sun's will broadcast even though this option can't be set */ 245 option = 1; 246 if (setsockopt(contactsock, SOL_SOCKET, SO_BROADCAST, 247 &option, sizeof option) < 0) { 248 leave(1, "setsockopt broadcast"); 249 /* NOTREACHED */ 250 } 251 #endif 252 253 /* send broadcast packets on all interfaces */ 254 wiremsg = htons(msg); 255 for (i = 0; i < numbroadcastaddrs; i++) { 256 contactaddr.sin_addr = broadcastaddrs[i].sin_addr; 257 if (sendto(contactsock, &wiremsg, sizeof(wiremsg), 0, 258 (struct sockaddr *)&contactaddr, 259 sizeof(contactaddr)) < 0) { 260 leave(1, "sendto"); 261 } 262 } 263 contactaddr.sin_addr = local_address; 264 if (sendto(contactsock, &wiremsg, sizeof(wiremsg), 0, 265 (struct sockaddr *)&contactaddr, sizeof(contactaddr)) < 0) { 266 leave(1, "sendto"); 267 } 268 } 269 270 static void 271 get_responses(int contactsock) 272 { 273 struct pollfd set[1]; 274 struct sockaddr_storage addr; 275 socklen_t addrlen; 276 int r; 277 uint16_t port_num; 278 ssize_t portlen; 279 280 /* forget all old responses */ 281 numdaemons = 0; 282 283 errno = 0; 284 set[0].fd = contactsock; 285 set[0].events = POLLIN; 286 for (;;) { 287 r = poll(set, 1, 1000); 288 if (r < 0) { 289 if (errno == EINTR) { 290 continue; 291 } 292 leave(1, "poll"); 293 } 294 if (r == 0) { 295 break; 296 } 297 298 addrlen = sizeof(addr); 299 portlen = recvfrom(contactsock, &port_num, sizeof(port_num), 0, 300 (struct sockaddr *)&addr, &addrlen); 301 if (portlen < 0) { 302 if (errno == EINTR) { 303 continue; 304 } 305 leave(1, "recvfrom"); 306 } 307 if (portlen == 0) { 308 leavex(1, "recvfrom: Unexpected EOF"); 309 } 310 if ((size_t)portlen != sizeof(port_num)) { 311 /* trash, ignore it */ 312 continue; 313 } 314 if (have_daemon_addr(&addr, addrlen)) { 315 /* this shouldn't happen */ 316 continue; 317 } 318 319 add_daemon_addr(&addr, addrlen, port_num); 320 } 321 322 initial = false; 323 } 324 325 void 326 serverlist_query(unsigned short msg) 327 { 328 int contactsock; 329 330 if (!initial && explicit_host != NULL) { 331 /* already did the work, no point doing it again */ 332 return; 333 } 334 335 contactsock = socket(SOCK_FAMILY, SOCK_DGRAM, 0); 336 if (contactsock < 0) { 337 leave(1, "socket system call failed"); 338 } 339 340 send_messages(contactsock, msg); 341 get_responses(contactsock); 342 343 (void) close(contactsock); 344 } 345 346 unsigned 347 serverlist_num(void) 348 { 349 return numdaemons; 350 } 351 352 const struct sockaddr_storage * 353 serverlist_gethost(unsigned i, socklen_t *len_ret) 354 { 355 struct sockaddr_in *ret; 356 357 assert(i < numdaemons); 358 ret = &daemons[i]; 359 *len_ret = sizeof(*ret); 360 return (struct sockaddr_storage *)ret; 361 } 362 363 unsigned short 364 serverlist_getresponse(unsigned i) 365 { 366 assert(i < numdaemons); 367 return daemons[i].sin_port; 368 } 369 370 #endif /* INTERNET */ 371
Indexes created Sun Sep 21 19:09:51 GMT 2025