ip.c revision 8857
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 1.3 1995/03/11 15:18:42 amurai 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 37extern void SendPppFrame(); 38extern int PacketCheck(); 39extern void LcpClose(); 40 41static struct pppTimer IdleTimer; 42 43static 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 */ 53void 54StartIdleTimer() 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 65void 66StopIdleTimer() 67{ 68 StopTimer(&IdleTimer); 69} 70 71/* 72 * If any IP layer traffic is detected, refresh IdleTimer. 73 */ 74static void 75RestartIdleTimer() 76{ 77 if (!(mode & MODE_DEDICATED) && ipKeepAlive ) { 78 StartTimer(&IdleTimer); 79 ipIdleSecs = 0; 80 } 81} 82 83static 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 89static char *TcpFlags[] = { 90 "FIN", "SYN", "RST", "PSH", "ACK", "URG", 91}; 92 93static char *Direction[] = { "INP", "OUT", "OUT", "IN/OUT" }; 94static struct filterent *Filters[] = { ifilters, ofilters, dfilters, afilters }; 95 96static int 97PortMatch(op, pport, rport) 98int op; 99u_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 */ 116static int 117FilterCheck(pip, direction) 118struct ip *pip; 119int 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#ifdef DEBUG 135logprintf("rule = %d\n", n); 136#endif 137 if ((pip->ip_src.s_addr & fp->smask.s_addr) == fp->saddr.s_addr 138 && (pip->ip_dst.s_addr & fp->dmask.s_addr) == fp->daddr.s_addr) { 139 if (fp->proto) { 140 if (!gotinfo) { 141 ptop = (char *)pip + (pip->ip_hl << 2); 142 143 switch (pip->ip_p) { 144 case IPPROTO_ICMP: 145 cproto = P_ICMP; ih = (struct icmp *)ptop; 146 sport = ih->icmp_type; estab = 1; 147 break; 148 case IPPROTO_UDP: 149 cproto = P_UDP; uh = (struct udphdr *)ptop; 150 sport = ntohs(uh->uh_sport); dport = ntohs(uh->uh_dport); 151 estab = 1; 152 break; 153 case IPPROTO_TCP: 154 cproto = P_TCP; th = (struct tcphdr *)ptop; 155 sport = ntohs(th->th_sport); dport = ntohs(th->th_dport); 156 estab = (th->th_flags & TH_ACK); 157#ifdef DEBUG 158if (estab == 0) 159logprintf("flag = %02x, sport = %d, dport = %d\n", th->th_flags, sport, dport); 160#endif 161 break; 162 default: 163 return(A_DENY); /* We'll block unknown type of packet */ 164 } 165 gotinfo = 1; 166#ifdef DEBUG 167logprintf("dir = %d, proto = %d, srcop = %d, dstop = %d, estab = %d\n", 168direction, cproto, fp->opt.srcop, fp->opt.dstop, estab); 169#endif 170 } 171#ifdef DEBUG 172 logprintf("check0: rule = %d, proto = %d, sport = %d, dport = %d\n", 173 n, cproto, sport, dport); 174 logprintf("check0: action = %d\n", fp->action); 175#endif 176 if (cproto == fp->proto) { 177 if ((fp->opt.srcop == OP_NONE || 178 PortMatch(fp->opt.srcop, sport, fp->opt.srcport)) 179 && 180 (fp->opt.dstop == OP_NONE || 181 PortMatch(fp->opt.dstop, dport, fp->opt.dstport)) 182 && 183 (fp->opt.estab == 0 || estab)) { 184 return(fp->action); 185 } 186 } 187 } else { 188 /* Address is mached. Make a decision. */ 189#ifdef DEBUG 190 logprintf("check1: action = %d\n", fp->action); 191#endif 192 return(fp->action); 193 } 194 } 195 } 196 fp++; 197 } 198drop: 199 return(A_DENY); /* No rule is mached. Deny this packet */ 200 } 201 return(A_PERMIT); /* No rule is given. Permit this packet */ 202} 203 204static void 205IcmpError(pip, code) 206struct ip *pip; 207int code; 208{ 209#ifdef notdef 210 struct mbuf *bp; 211 212 if (pip->ip_p != IPPROTO_ICMP) { 213 bp = mballoc(cnt, MB_IPIN); 214 bcopy(ptr, MBUF_CTOP(bp), cnt); 215 SendPppFrame(PRI_URGENT, bp); 216 RestartIdleTimer(); 217 ipOutOctets += cnt; 218 } 219#endif 220} 221 222/* 223 * For debugging aid. 224 */ 225int 226PacketCheck(cp, nb, direction) 227char *cp; 228int nb; 229int direction; 230{ 231 struct ip *pip; 232 struct tcphdr *th; 233 struct udphdr *uh; 234 struct icmp *icmph; 235 char *ptop; 236 int mask, len, n; 237 int logit; 238 int pri = PRI_NORMAL; 239 240 logit = (loglevel & (1 << LOG_TCPIP)); 241 242 pip = (struct ip *)cp; 243 244 if (logit) logprintf("%s ", Direction[direction]); 245 246 ptop = (cp + (pip->ip_hl << 2)); 247 248 switch (pip->ip_p) { 249 case IPPROTO_ICMP: 250 if (logit) { 251 icmph = (struct icmp *)ptop; 252 logprintf("ICMP: %s:%d ---> ", inet_ntoa(pip->ip_src), icmph->icmp_type); 253 logprintf("%s:%d\n", inet_ntoa(pip->ip_dst), icmph->icmp_type); 254 } 255 break; 256 case IPPROTO_UDP: 257 if (logit) { 258 uh = (struct udphdr *)ptop; 259 logprintf("UDP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport)); 260 logprintf("%s:%d\n", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport)); 261 } 262 break; 263 case IPPROTO_TCP: 264 th = (struct tcphdr *)ptop; 265 if (pip->ip_tos == IPTOS_LOWDELAY) 266 pri = PRI_FAST; 267 else if (pip->ip_off == 0) { 268 if (INTERACTIVE(ntohs(th->th_sport)) || INTERACTIVE(ntohs(th->th_dport))) 269 pri = PRI_FAST; 270 } 271 272 if (logit) { 273 len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - (th->th_off << 2); 274 logprintf("TCP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(th->th_sport)); 275 logprintf("%s:%d", inet_ntoa(pip->ip_dst), ntohs(th->th_dport)); 276 n = 0; 277 for (mask = TH_FIN; mask != 0x40; mask <<= 1) { 278 if (th->th_flags & mask) 279 logprintf(" %s", TcpFlags[n]); 280 n++; 281 } 282 logprintf(" seq:%x ack:%x (%d/%d)\n", 283 ntohl(th->th_seq), ntohl(th->th_ack), len, nb); 284 if ((th->th_flags & TH_SYN) && nb > 40) { 285 u_short *sp; 286 287 ptop += 20; 288 sp = (u_short *)ptop; 289 if (ntohs(sp[0]) == 0x0204) 290 logprintf(" MSS = %d\n", ntohs(sp[1])); 291 } 292 } 293 break; 294 } 295 pri = FilterCheck(pip, direction); 296 if (pri & A_DENY) { 297#ifdef DEBUG 298 logprintf("blocked.\n"); 299#endif 300 if (direction == 0) IcmpError(pip, pri); 301 return(-1); 302 } else { 303 if ( FilterCheck(pip, FL_KEEP ) & A_DENY ) { /* Check Keep Alive filter */ 304 ipKeepAlive = FALSE; 305 } else { 306 ipKeepAlive = TRUE; 307 } 308 return(pri); 309 } 310} 311 312void 313IpInput(bp) 314struct mbuf *bp; /* IN: Pointer to IP pakcet */ 315{ 316 u_char *cp; 317 struct mbuf *wp; 318 int nb, nw; 319 u_char tunbuff[MAX_MRU]; 320 321 cp = tunbuff; 322 nb = 0; 323 for (wp = bp; wp; wp = wp->next) { /* Copy to continuois region */ 324 bcopy(MBUF_CTOP(wp), cp, wp->cnt); 325 cp += wp->cnt; 326 nb += wp->cnt; 327 } 328 329 if ( PacketCheck(tunbuff, nb, FL_IN ) < 0) { 330 pfree(bp); 331 return; 332 } 333 334 ipInOctets += nb; 335 /* 336 * Pass it to tunnel device 337 */ 338 nw = write(tun_out, tunbuff, nb); 339 if (nw != nb) 340 fprintf(stderr, "wrote %d, got %d\r\n"); 341 pfree(bp); 342 343 RestartIdleTimer(); 344} 345 346void 347IpOutput(ptr, cnt) 348u_char *ptr; /* IN: Pointer to IP packet */ 349int cnt; /* IN: Length of packet */ 350{ 351 struct mbuf *bp; 352 int pri; 353 354 if (IpcpFsm.state != ST_OPENED) 355 return; 356 357 pri = PacketCheck(ptr, cnt, FL_OUT); 358 if (pri >= 0) { 359 bp = mballoc(cnt, MB_IPIN); 360 bcopy(ptr, MBUF_CTOP(bp), cnt); 361 SendPppFrame(pri, bp); 362 RestartIdleTimer(); 363 ipOutOctets += cnt; 364 } 365} 366 367static struct mqueue IpOutputQueues[PRI_URGENT+1]; 368 369void 370IpEnqueue(pri, ptr, count) 371int pri; 372char *ptr; 373int count; 374{ 375 struct mbuf *bp; 376 377 bp = mballoc(count, MB_IPQ); 378 bcopy(ptr, MBUF_CTOP(bp), count); 379 Enqueue(&IpOutputQueues[pri], bp); 380} 381 382int 383IsIpEnqueued() 384{ 385 struct mqueue *queue; 386 int exist = FALSE; 387 for (queue = &IpOutputQueues[PRI_URGENT]; queue >= IpOutputQueues; queue--) { 388 if ( queue->qlen > 0 ) { 389 exist = TRUE; 390 break; 391 } 392 } 393 return( exist ); 394} 395 396void 397IpStartOutput() 398{ 399 struct mqueue *queue; 400 struct mbuf *bp; 401 int pri, cnt; 402 403 if (IpcpFsm.state != ST_OPENED) 404 return; 405 pri = PRI_URGENT; 406 for (queue = &IpOutputQueues[PRI_URGENT]; queue >= IpOutputQueues; queue--) { 407 if (queue->top) { 408 bp = Dequeue(queue); 409 if (bp) { 410 cnt = plength(bp); 411 SendPppFrame(pri, bp); 412 RestartIdleTimer(); 413 ipOutOctets += cnt; 414 } 415 } 416 pri--; 417 } 418} 419