1 /* 2 * PPP IP Protocol Interface 3 * 4 * Written by Toshiharu OHNO (tony-o@iij.ad.jp) 5 * 6 * Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd. 7 * 8 * Redistribution and use in source and binary forms are permitted 9 * provided that the above copyright notice and this paragraph are 10 * duplicated in all such forms and that any documentation, 11 * advertising materials, and other materials related to such 12 * distribution and use acknowledge that the software was developed 13 * by the Internet Initiative Japan. The name of the 14 * IIJ may not be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 19 * 20 * $Id: ip.c,v 1.4 1995/05/30 03:50:37 rgrimes Exp $ 21 * 22 * TODO: 23 * o Return ICMP message for filterd packet 24 * and optionaly record it into log. 25 */ 26 #include "fsm.h" 27 #include "lcpproto.h" 28 #include "hdlc.h" 29 #include <netinet/in_systm.h> 30 #include <netinet/ip.h> 31 #include <netinet/ip_icmp.h> 32 #include <netinet/udp.h> 33 #include <netinet/tcp.h> 34 #include "vars.h" 35 #include "filter.h" 36 37 extern void SendPppFrame(); 38 extern int PacketCheck(); 39 extern void LcpClose(); 40 41 static struct pppTimer IdleTimer; 42 43 static void IdleTimeout() 44 { 45 LogPrintf(LOG_PHASE, "Idle timer expired.\n"); 46 LcpClose(); 47 } 48 49 /* 50 * Start Idle timer. If timeout is reached, we call LcpClose() to 51 * close LCP and link. 52 */ 53 void 54 StartIdleTimer() 55 { 56 if (!(mode & MODE_DEDICATED)) { 57 StopTimer(&IdleTimer); 58 IdleTimer.func = IdleTimeout; 59 IdleTimer.load = VarIdleTimeout * SECTICKS; 60 IdleTimer.state = TIMER_STOPPED; 61 StartTimer(&IdleTimer); 62 } 63 } 64 65 void 66 StopIdleTimer() 67 { 68 StopTimer(&IdleTimer); 69 } 70 71 /* 72 * If any IP layer traffic is detected, refresh IdleTimer. 73 */ 74 static void 75 RestartIdleTimer() 76 { 77 if (!(mode & MODE_DEDICATED) && ipKeepAlive ) { 78 StartTimer(&IdleTimer); 79 ipIdleSecs = 0; 80 } 81 } 82 83 static u_short interactive_ports[8] = { 84 0, 513, 0, 0, 0, 21, 0, 23, 85 }; 86 87 #define INTERACTIVE(p) (interactive_ports[(p) & 7] == (p)) 88 89 static char *TcpFlags[] = { 90 "FIN", "SYN", "RST", "PSH", "ACK", "URG", 91 }; 92 93 static char *Direction[] = { "INP", "OUT", "OUT", "IN/OUT" }; 94 static struct filterent *Filters[] = { ifilters, ofilters, dfilters, afilters }; 95 96 static int 97 PortMatch(op, pport, rport) 98 int op; 99 u_short pport, rport; 100 { 101 switch (op) { 102 case OP_EQ: 103 return(pport == rport); 104 case OP_GT: 105 return(pport > rport); 106 case OP_LT: 107 return(pport < rport); 108 default: 109 return(0); 110 } 111 } 112 113 /* 114 * Check a packet against with defined filters 115 */ 116 static int 117 FilterCheck(pip, direction) 118 struct ip *pip; 119 int direction; 120 { 121 struct filterent *fp = Filters[direction]; 122 int gotinfo, cproto, estab, n; 123 struct tcphdr *th; 124 struct udphdr *uh; 125 struct icmp *ih; 126 char *ptop; 127 u_short sport, dport; 128 129 if (fp->action) { 130 cproto = gotinfo = estab = 0; 131 sport = dport = 0; 132 for (n = 0; n < MAXFILTERS; n++) { 133 if (fp->action) { 134 /* permit fragments on in and out filter */ 135 if ((direction == FL_IN || direction == FL_OUT) && 136 (pip->ip_off & IP_OFFMASK) != 0) { 137 return(A_PERMIT); 138 } 139 #ifdef DEBUG 140 logprintf("rule = %d\n", n); 141 #endif 142 if ((pip->ip_src.s_addr & fp->smask.s_addr) == fp->saddr.s_addr 143 && (pip->ip_dst.s_addr & fp->dmask.s_addr) == fp->daddr.s_addr) { 144 if (fp->proto) { 145 if (!gotinfo) { 146 ptop = (char *)pip + (pip->ip_hl << 2); 147 148 switch (pip->ip_p) { 149 case IPPROTO_ICMP: 150 cproto = P_ICMP; ih = (struct icmp *)ptop; 151 sport = ih->icmp_type; estab = 1; 152 break; 153 case IPPROTO_UDP: 154 cproto = P_UDP; uh = (struct udphdr *)ptop; 155 sport = ntohs(uh->uh_sport); dport = ntohs(uh->uh_dport); 156 estab = 1; 157 break; 158 case IPPROTO_TCP: 159 cproto = P_TCP; th = (struct tcphdr *)ptop; 160 sport = ntohs(th->th_sport); dport = ntohs(th->th_dport); 161 estab = (th->th_flags & TH_ACK); 162 #ifdef DEBUG 163 if (estab == 0) 164 logprintf("flag = %02x, sport = %d, dport = %d\n", th->th_flags, sport, dport); 165 #endif 166 break; 167 default: 168 return(A_DENY); /* We'll block unknown type of packet */ 169 } 170 gotinfo = 1; 171 #ifdef DEBUG 172 logprintf("dir = %d, proto = %d, srcop = %d, dstop = %d, estab = %d\n", 173 direction, cproto, fp->opt.srcop, fp->opt.dstop, estab); 174 #endif 175 } 176 #ifdef DEBUG 177 logprintf("check0: rule = %d, proto = %d, sport = %d, dport = %d\n", 178 n, cproto, sport, dport); 179 logprintf("check0: action = %d\n", fp->action); 180 #endif 181 if (cproto == fp->proto) { 182 if ((fp->opt.srcop == OP_NONE || 183 PortMatch(fp->opt.srcop, sport, fp->opt.srcport)) 184 && 185 (fp->opt.dstop == OP_NONE || 186 PortMatch(fp->opt.dstop, dport, fp->opt.dstport)) 187 && 188 (fp->opt.estab == 0 || estab)) { 189 return(fp->action); 190 } 191 } 192 } else { 193 /* Address is mached. Make a decision. */ 194 #ifdef DEBUG 195 logprintf("check1: action = %d\n", fp->action); 196 #endif 197 return(fp->action); 198 } 199 } 200 } 201 fp++; 202 } 203 drop: 204 return(A_DENY); /* No rule is mached. Deny this packet */ 205 } 206 return(A_PERMIT); /* No rule is given. Permit this packet */ 207 } 208 209 static void 210 IcmpError(pip, code) 211 struct ip *pip; 212 int code; 213 { 214 #ifdef notdef 215 struct mbuf *bp; 216 217 if (pip->ip_p != IPPROTO_ICMP) { 218 bp = mballoc(cnt, MB_IPIN); 219 bcopy(ptr, MBUF_CTOP(bp), cnt); 220 SendPppFrame(PRI_URGENT, bp); 221 RestartIdleTimer(); 222 ipOutOctets += cnt; 223 } 224 #endif 225 } 226 227 /* 228 * For debugging aid. 229 */ 230 int 231 PacketCheck(cp, nb, direction) 232 char *cp; 233 int nb; 234 int direction; 235 { 236 struct ip *pip; 237 struct tcphdr *th; 238 struct udphdr *uh; 239 struct icmp *icmph; 240 char *ptop; 241 int mask, len, n; 242 int logit; 243 int pri = PRI_NORMAL; 244 245 logit = (loglevel & (1 << LOG_TCPIP)); 246 247 pip = (struct ip *)cp; 248 249 if (logit) logprintf("%s ", Direction[direction]); 250 251 ptop = (cp + (pip->ip_hl << 2)); 252 253 switch (pip->ip_p) { 254 case IPPROTO_ICMP: 255 if (logit) { 256 icmph = (struct icmp *)ptop; 257 logprintf("ICMP: %s:%d ---> ", inet_ntoa(pip->ip_src), icmph->icmp_type); 258 logprintf("%s:%d\n", inet_ntoa(pip->ip_dst), icmph->icmp_type); 259 } 260 break; 261 case IPPROTO_UDP: 262 if (logit) { 263 uh = (struct udphdr *)ptop; 264 logprintf("UDP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport)); 265 logprintf("%s:%d\n", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport)); 266 } 267 break; 268 case IPPROTO_TCP: 269 th = (struct tcphdr *)ptop; 270 if (pip->ip_tos == IPTOS_LOWDELAY) 271 pri = PRI_FAST; 272 else if (pip->ip_off == 0) { 273 if (INTERACTIVE(ntohs(th->th_sport)) || INTERACTIVE(ntohs(th->th_dport))) 274 pri = PRI_FAST; 275 } 276 277 if (logit) { 278 len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - (th->th_off << 2); 279 logprintf("TCP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(th->th_sport)); 280 logprintf("%s:%d", inet_ntoa(pip->ip_dst), ntohs(th->th_dport)); 281 n = 0; 282 for (mask = TH_FIN; mask != 0x40; mask <<= 1) { 283 if (th->th_flags & mask) 284 logprintf(" %s", TcpFlags[n]); 285 n++; 286 } 287 logprintf(" seq:%x ack:%x (%d/%d)\n", 288 ntohl(th->th_seq), ntohl(th->th_ack), len, nb); 289 if ((th->th_flags & TH_SYN) && nb > 40) { 290 u_short *sp; 291 292 ptop += 20; 293 sp = (u_short *)ptop; 294 if (ntohs(sp[0]) == 0x0204) 295 logprintf(" MSS = %d\n", ntohs(sp[1])); 296 } 297 } 298 break; 299 } 300 pri = FilterCheck(pip, direction); 301 if (pri & A_DENY) { 302 #ifdef DEBUG 303 logprintf("blocked.\n"); 304 #endif 305 if (direction == 0) IcmpError(pip, pri); 306 return(-1); 307 } else { 308 if ( FilterCheck(pip, FL_KEEP ) & A_DENY ) { /* Check Keep Alive filter */ 309 ipKeepAlive = FALSE; 310 } else { 311 ipKeepAlive = TRUE; 312 } 313 return(pri); 314 } 315 } 316 317 void 318 IpInput(bp) 319 struct mbuf *bp; /* IN: Pointer to IP pakcet */ 320 { 321 u_char *cp; 322 struct mbuf *wp; 323 int nb, nw; 324 u_char tunbuff[MAX_MRU]; 325 326 cp = tunbuff; 327 nb = 0; 328 for (wp = bp; wp; wp = wp->next) { /* Copy to continuois region */ 329 bcopy(MBUF_CTOP(wp), cp, wp->cnt); 330 cp += wp->cnt; 331 nb += wp->cnt; 332 } 333 334 if ( PacketCheck(tunbuff, nb, FL_IN ) < 0) { 335 pfree(bp); 336 return; 337 } 338 339 ipInOctets += nb; 340 /* 341 * Pass it to tunnel device 342 */ 343 nw = write(tun_out, tunbuff, nb); 344 if (nw != nb) 345 fprintf(stderr, "wrote %d, got %d\r\n"); 346 pfree(bp); 347 348 RestartIdleTimer(); 349 } 350 351 void 352 IpOutput(ptr, cnt) 353 u_char *ptr; /* IN: Pointer to IP packet */ 354 int cnt; /* IN: Length of packet */ 355 { 356 struct mbuf *bp; 357 int pri; 358 359 if (IpcpFsm.state != ST_OPENED) 360 return; 361 362 pri = PacketCheck(ptr, cnt, FL_OUT); 363 if (pri >= 0) { 364 bp = mballoc(cnt, MB_IPIN); 365 bcopy(ptr, MBUF_CTOP(bp), cnt); 366 SendPppFrame(pri, bp); 367 RestartIdleTimer(); 368 ipOutOctets += cnt; 369 } 370 } 371 372 static struct mqueue IpOutputQueues[PRI_URGENT+1]; 373 374 void 375 IpEnqueue(pri, ptr, count) 376 int pri; 377 char *ptr; 378 int count; 379 { 380 struct mbuf *bp; 381 382 bp = mballoc(count, MB_IPQ); 383 bcopy(ptr, MBUF_CTOP(bp), count); 384 Enqueue(&IpOutputQueues[pri], bp); 385 } 386 387 int 388 IsIpEnqueued() 389 { 390 struct mqueue *queue; 391 int exist = FALSE; 392 for (queue = &IpOutputQueues[PRI_URGENT]; queue >= IpOutputQueues; queue--) { 393 if ( queue->qlen > 0 ) { 394 exist = TRUE; 395 break; 396 } 397 } 398 return( exist ); 399 } 400 401 void 402 IpStartOutput() 403 { 404 struct mqueue *queue; 405 struct mbuf *bp; 406 int pri, cnt; 407 408 if (IpcpFsm.state != ST_OPENED) 409 return; 410 pri = PRI_URGENT; 411 for (queue = &IpOutputQueues[PRI_URGENT]; queue >= IpOutputQueues; queue--) { 412 if (queue->top) { 413 bp = Dequeue(queue); 414 if (bp) { 415 cnt = plength(bp); 416 SendPppFrame(pri, bp); 417 RestartIdleTimer(); 418 ipOutOctets += cnt; 419 } 420 } 421 pri--; 422 } 423 } 424