sys/src/9/ip/icmp.c

   1 #include "u.h"
   2 #include "../port/lib.h"
   3 #include "mem.h"
   4 #include "dat.h"
   5 #include "fns.h"
   6 #include "../port/error.h"
   7
   8 #include "ip.h"
   9
  10 typedef struct Icmp {
  11         uchar   vihl;           /* Version and header length */
  12         uchar   tos;            /* Type of service */
  13         uchar   length[2];      /* packet length */
  14         uchar   id[2];          /* Identification */
  15         uchar   frag[2];        /* Fragment information */
  16         uchar   ttl;            /* Time to live */
  17         uchar   proto;          /* Protocol */
  18         uchar   ipcksum[2];     /* Header checksum */
  19         uchar   src[4];         /* Ip source */
  20         uchar   dst[4];         /* Ip destination */
  21         uchar   type;
  22         uchar   code;
  23         uchar   cksum[2];
  24         uchar   icmpid[2];
  25         uchar   seq[2];
  26         uchar   data[1];
  27 } Icmp;
  28
  29 enum {                  /* Packet Types */
  30         EchoReply       = 0,
  31         Unreachable     = 3,
  32         SrcQuench       = 4,
  33         Redirect        = 5,
  34         EchoRequest     = 8,
  35         TimeExceed      = 11,
  36         InParmProblem   = 12,
  37         Timestamp       = 13,
  38         TimestampReply  = 14,
  39         InfoRequest     = 15,
  40         InfoReply       = 16,
  41         AddrMaskRequest = 17,
  42         AddrMaskReply   = 18,
  43
  44         Maxtype         = 18,
  45 };
  46
  47 enum
  48 {
  49         MinAdvise       = 24,   /* minimum needed for us to advise another protocol */
  50 };
  51
  52 char *icmpnames[Maxtype+1] =
  53 {
  54 [EchoReply]             "EchoReply",
  55 [Unreachable]           "Unreachable",
  56 [SrcQuench]             "SrcQuench",
  57 [Redirect]              "Redirect",
  58 [EchoRequest]           "EchoRequest",
  59 [TimeExceed]            "TimeExceed",
  60 [InParmProblem]         "InParmProblem",
  61 [Timestamp]             "Timestamp",
  62 [TimestampReply]        "TimestampReply",
  63 [InfoRequest]           "InfoRequest",
  64 [InfoReply]             "InfoReply",
  65 [AddrMaskRequest]       "AddrMaskRequest",
  66 [AddrMaskReply  ]       "AddrMaskReply  ",
  67 };
  68
  69 enum {
  70         IP_ICMPPROTO    = 1,
  71         ICMP_IPSIZE     = 20,
  72         ICMP_HDRSIZE    = 8,
  73 };
  74
  75 enum
  76 {
  77         InMsgs,
  78         InErrors,
  79         OutMsgs,
  80         CsumErrs,
  81         LenErrs,
  82         HlenErrs,
  83
  84         Nstats,
  85 };
  86
  87 static char *statnames[Nstats] =
  88 {
  89 [InMsgs]        "InMsgs",
  90 [InErrors]      "InErrors",
  91 [OutMsgs]       "OutMsgs",
  92 [CsumErrs]      "CsumErrs",
  93 [LenErrs]       "LenErrs",
  94 [HlenErrs]      "HlenErrs",
  95 };
  96
  97 typedef struct Icmppriv Icmppriv;
  98 struct Icmppriv
  99 {
 100         ulong   stats[Nstats];
 101
 102         /* message counts */
 103         ulong   in[Maxtype+1];
 104         ulong   out[Maxtype+1];
 105 };
 106
 107 static void icmpkick(void *x, Block*);
 108
 109 static void
 110 icmpcreate(Conv *c)
 111 {
 112         c->rq = qopen(64*1024, Qmsg, 0, c);
 113         c->wq = qbypass(icmpkick, c);
 114 }
 115
 116 extern char*
 117 icmpconnect(Conv *c, char **argv, int argc)
 118 {
 119         char *e;
 120
 121         e = Fsstdconnect(c, argv, argc);
 122         if(e != nil)
 123                 return e;
 124         Fsconnected(c, e);
 125
 126         return nil;
 127 }
 128
 129 extern int
 130 icmpstate(Conv *c, char *state, int n)
 131 {
 132         USED(c);
 133         return snprint(state, n, "%s qin %d qout %d\n",
 134                 "Datagram",
 135                 c->rq ? qlen(c->rq) : 0,
 136                 c->wq ? qlen(c->wq) : 0
 137         );
 138 }
 139
 140 extern char*
 141 icmpannounce(Conv *c, char **argv, int argc)
 142 {
 143         char *e;
 144
 145         e = Fsstdannounce(c, argv, argc);
 146         if(e != nil)
 147                 return e;
 148         Fsconnected(c, nil);
 149
 150         return nil;
 151 }
 152
 153 extern void
 154 icmpclose(Conv *c)
 155 {
 156         qclose(c->rq);
 157         qclose(c->wq);
 158         ipmove(c->laddr, IPnoaddr);
 159         ipmove(c->raddr, IPnoaddr);
 160         c->lport = 0;
 161 }
 162
 163 static void
 164 icmpkick(void *x, Block *bp)
 165 {
 166         Conv *c = x;
 167         Icmp *p;
 168         Icmppriv *ipriv;
 169
 170         if(bp == nil)
 171                 return;
 172
 173         if(blocklen(bp) < ICMP_IPSIZE + ICMP_HDRSIZE){
 174                 freeblist(bp);
 175                 return;
 176         }
 177         p = (Icmp *)(bp->rp);
 178         p->vihl = IP_VER4;
 179         ipriv = c->p->priv;
 180         if(p->type <= Maxtype)
 181                 ipriv->out[p->type]++;
 182
 183         v6tov4(p->dst, c->raddr);
 184         v6tov4(p->src, c->laddr);
 185         p->proto = IP_ICMPPROTO;
 186         hnputs(p->icmpid, c->lport);
 187         memset(p->cksum, 0, sizeof(p->cksum));
 188         hnputs(p->cksum, ptclcsum(bp, ICMP_IPSIZE, blocklen(bp) - ICMP_IPSIZE));
 189         ipriv->stats[OutMsgs]++;
 190         ipoput4(c->p->f, bp, 0, c->ttl, c->tos, nil);
 191 }
 192
 193 extern void
 194 icmpttlexceeded(Fs *f, uchar *ia, Block *bp)
 195 {
 196         Block   *nbp;
 197         Icmp    *p, *np;
 198
 199         p = (Icmp *)bp->rp;
 200
 201         netlog(f, Logicmp, "sending icmpttlexceeded -> %V\n", p->src);
 202         nbp = allocb(ICMP_IPSIZE + ICMP_HDRSIZE + ICMP_IPSIZE + 8);
 203         nbp->wp += ICMP_IPSIZE + ICMP_HDRSIZE + ICMP_IPSIZE + 8;
 204         np = (Icmp *)nbp->rp;
 205         np->vihl = IP_VER4;
 206         memmove(np->dst, p->src, sizeof(np->dst));
 207         v6tov4(np->src, ia);
 208         memmove(np->data, bp->rp, ICMP_IPSIZE + 8);
 209         np->type = TimeExceed;
 210         np->code = 0;
 211         np->proto = IP_ICMPPROTO;
 212         hnputs(np->icmpid, 0);
 213         hnputs(np->seq, 0);
 214         memset(np->cksum, 0, sizeof(np->cksum));
 215         hnputs(np->cksum, ptclcsum(nbp, ICMP_IPSIZE, blocklen(nbp) - ICMP_IPSIZE));
 216         ipoput4(f, nbp, 0, MAXTTL, DFLTTOS, nil);
 217
 218 }
 219
 220 static void
 221 icmpunreachable(Fs *f, Block *bp, int code, int seq)
 222 {
 223         Block   *nbp;
 224         Icmp    *p, *np;
 225         int     i;
 226         uchar   addr[IPaddrlen];
 227
 228         p = (Icmp *)bp->rp;
 229
 230         /* only do this for unicast sources and destinations */
 231         v4tov6(addr, p->dst);
 232         i = ipforme(f, addr);
 233         if((i&Runi) == 0)
 234                 return;
 235         v4tov6(addr, p->src);
 236         i = ipforme(f, addr);
 237         if(i != 0 && (i&Runi) == 0)
 238                 return;
 239
 240         netlog(f, Logicmp, "sending icmpnoconv -> %V\n", p->src);
 241         nbp = allocb(ICMP_IPSIZE + ICMP_HDRSIZE + ICMP_IPSIZE + 8);
 242         nbp->wp += ICMP_IPSIZE + ICMP_HDRSIZE + ICMP_IPSIZE + 8;
 243         np = (Icmp *)nbp->rp;
 244         np->vihl = IP_VER4;
 245         memmove(np->dst, p->src, sizeof(np->dst));
 246         memmove(np->src, p->dst, sizeof(np->src));
 247         memmove(np->data, bp->rp, ICMP_IPSIZE + 8);
 248         np->type = Unreachable;
 249         np->code = code;
 250         np->proto = IP_ICMPPROTO;
 251         hnputs(np->icmpid, 0);
 252         hnputs(np->seq, seq);
 253         memset(np->cksum, 0, sizeof(np->cksum));
 254         hnputs(np->cksum, ptclcsum(nbp, ICMP_IPSIZE, blocklen(nbp) - ICMP_IPSIZE));
 255         ipoput4(f, nbp, 0, MAXTTL, DFLTTOS, nil);
 256 }
 257
 258 extern void
 259 icmpnoconv(Fs *f, Block *bp)
 260 {
 261         icmpunreachable(f, bp, 3, 0);
 262 }
 263
 264 extern void
 265 icmpcantfrag(Fs *f, Block *bp, int mtu)
 266 {
 267         icmpunreachable(f, bp, 4, mtu);
 268 }
 269
 270 static void
 271 goticmpkt(Proto *icmp, Block *bp)
 272 {
 273         Conv    **c, *s;
 274         Icmp    *p;
 275         uchar   dst[IPaddrlen];
 276         ushort  recid;
 277
 278         p = (Icmp *) bp->rp;
 279         v4tov6(dst, p->src);
 280         recid = nhgets(p->icmpid);
 281
 282         for(c = icmp->conv; *c; c++) {
 283                 s = *c;
 284                 if(s->lport == recid)
 285                 if(ipcmp(s->raddr, dst) == 0){
 286                         bp = concatblock(bp);
 287                         if(bp != nil)
 288                                 qpass(s->rq, bp);
 289                         return;
 290                 }
 291         }
 292         freeblist(bp);
 293 }
 294
 295 static Block *
 296 mkechoreply(Block *bp)
 297 {
 298         Icmp    *q;
 299         uchar   ip[4];
 300
 301         q = (Icmp *)bp->rp;
 302         q->vihl = IP_VER4;
 303         memmove(ip, q->src, sizeof(q->dst));
 304         memmove(q->src, q->dst, sizeof(q->src));
 305         memmove(q->dst, ip,  sizeof(q->dst));
 306         q->type = EchoReply;
 307         memset(q->cksum, 0, sizeof(q->cksum));
 308         hnputs(q->cksum, ptclcsum(bp, ICMP_IPSIZE, blocklen(bp) - ICMP_IPSIZE));
 309
 310         return bp;
 311 }
 312
 313 static char *unreachcode[] =
 314 {
 315 [0]     "net unreachable",
 316 [1]     "host unreachable",
 317 [2]     "protocol unreachable",
 318 [3]     "port unreachable",
 319 [4]     "fragmentation needed and DF set",
 320 [5]     "source route failed",
 321 [6]     "destination network unknown",
 322 [7]     "destination host unknown",
 323 [8]     "source host isolated",
 324 [9]     "network administratively prohibited",
 325 [10]    "host administratively prohibited",
 326 [11]    "network unreachable for tos",
 327 [12]    "host unreachable for tos",
 328 [13]    "communication administratively prohibited",
 329 [14]    "host precedence violation",
 330 [15]    "precedence cutoff in effect",
 331 };
 332
 333 static void
 334 icmpiput(Proto *icmp, Ipifc*, Block *bp)
 335 {
 336         int     n, iplen;
 337         Icmp    *p;
 338         Block   *r;
 339         Proto   *pr;
 340         char    *msg;
 341         char    m2[128];
 342         Icmppriv *ipriv;
 343
 344         ipriv = icmp->priv;
 345
 346         ipriv->stats[InMsgs]++;
 347
 348         p = (Icmp *)bp->rp;
 349         netlog(icmp->f, Logicmp, "icmpiput %s (%d) %d\n",
 350                 (p->type < nelem(icmpnames)? icmpnames[p->type]: ""),
 351                 p->type, p->code);
 352         n = blocklen(bp);
 353         if(n < ICMP_IPSIZE+ICMP_HDRSIZE){
 354                 ipriv->stats[InErrors]++;
 355                 ipriv->stats[HlenErrs]++;
 356                 netlog(icmp->f, Logicmp, "icmp hlen %d\n", n);
 357                 goto raise;
 358         }
 359         iplen = nhgets(p->length);
 360         if(iplen > n){
 361                 ipriv->stats[LenErrs]++;
 362                 ipriv->stats[InErrors]++;
 363                 netlog(icmp->f, Logicmp, "icmp length %d\n", iplen);
 364                 goto raise;
 365         }
 366         if(ptclcsum(bp, ICMP_IPSIZE, iplen - ICMP_IPSIZE)){
 367                 ipriv->stats[InErrors]++;
 368                 ipriv->stats[CsumErrs]++;
 369                 netlog(icmp->f, Logicmp, "icmp checksum error\n");
 370                 goto raise;
 371         }
 372         if(p->type <= Maxtype)
 373                 ipriv->in[p->type]++;
 374
 375         switch(p->type) {
 376         case EchoRequest:
 377                 if (iplen < n)
 378                         bp = trimblock(bp, 0, iplen);
 379                 r = mkechoreply(concatblock(bp));
 380                 ipriv->out[EchoReply]++;
 381                 ipoput4(icmp->f, r, 0, MAXTTL, DFLTTOS, nil);
 382                 break;
 383         case Unreachable:
 384                 if(p->code >= nelem(unreachcode)) {
 385                         snprint(m2, sizeof m2, "unreachable %V->%V code %d",
 386                                 p->src, p->dst, p->code);
 387                         msg = m2;
 388                 } else
 389                         msg = unreachcode[p->code];
 390
 391                 bp->rp += ICMP_IPSIZE+ICMP_HDRSIZE;
 392                 if(blocklen(bp) < MinAdvise){
 393                         ipriv->stats[LenErrs]++;
 394                         goto raise;
 395                 }
 396                 p = (Icmp *)bp->rp;
 397                 pr = Fsrcvpcolx(icmp->f, p->proto);
 398                 if(pr != nil && pr->advise != nil) {
 399                         (*pr->advise)(pr, bp, msg);
 400                         return;
 401                 }
 402
 403                 bp->rp -= ICMP_IPSIZE+ICMP_HDRSIZE;
 404                 goticmpkt(icmp, bp);
 405                 break;
 406         case TimeExceed:
 407                 if(p->code == 0){
 408                         snprint(m2, sizeof m2, "ttl exceeded at %V", p->src);
 409
 410                         bp->rp += ICMP_IPSIZE+ICMP_HDRSIZE;
 411                         if(blocklen(bp) < MinAdvise){
 412                                 ipriv->stats[LenErrs]++;
 413                                 goto raise;
 414                         }
 415                         p = (Icmp *)bp->rp;
 416                         pr = Fsrcvpcolx(icmp->f, p->proto);
 417                         if(pr != nil && pr->advise != nil) {
 418                                 (*pr->advise)(pr, bp, m2);
 419                                 return;
 420                         }
 421                         bp->rp -= ICMP_IPSIZE+ICMP_HDRSIZE;
 422                 }
 423
 424                 goticmpkt(icmp, bp);
 425                 break;
 426         default:
 427                 goticmpkt(icmp, bp);
 428                 break;
 429         }
 430         return;
 431
 432 raise:
 433         freeblist(bp);
 434 }
 435
 436 void
 437 icmpadvise(Proto *icmp, Block *bp, char *msg)
 438 {
 439         Conv    **c, *s;
 440         Icmp    *p;
 441         uchar   dst[IPaddrlen];
 442         ushort  recid;
 443
 444         p = (Icmp *) bp->rp;
 445         v4tov6(dst, p->dst);
 446         recid = nhgets(p->icmpid);
 447
 448         for(c = icmp->conv; *c; c++) {
 449                 s = *c;
 450                 if(s->lport == recid)
 451                 if(ipcmp(s->raddr, dst) == 0){
 452                         if(s->ignoreadvice)
 453                                 break;
 454                         qhangup(s->rq, msg);
 455                         qhangup(s->wq, msg);
 456                         break;
 457                 }
 458         }
 459         freeblist(bp);
 460 }
 461
 462 int
 463 icmpstats(Proto *icmp, char *buf, int len)
 464 {
 465         Icmppriv *priv;
 466         char *p, *e;
 467         int i;
 468
 469         priv = icmp->priv;
 470         p = buf;
 471         e = p+len;
 472         for(i = 0; i < Nstats; i++)
 473                 p = seprint(p, e, "%s: %lud\n", statnames[i], priv->stats[i]);
 474         for(i = 0; i <= Maxtype; i++){
 475                 if(icmpnames[i])
 476                         p = seprint(p, e, "%s: %lud %lud\n", icmpnames[i], priv->in[i], priv->out[i]);
 477                 else
 478                         p = seprint(p, e, "%d: %lud %lud\n", i, priv->in[i], priv->out[i]);
 479         }
 480         return p - buf;
 481 }
 482
 483 void
 484 icmpinit(Fs *fs)
 485 {
 486         Proto *icmp;
 487
 488         icmp = smalloc(sizeof(Proto));
 489         icmp->priv = smalloc(sizeof(Icmppriv));
 490         icmp->name = "icmp";
 491         icmp->connect = icmpconnect;
 492         icmp->announce = icmpannounce;
 493         icmp->state = icmpstate;
 494         icmp->create = icmpcreate;
 495         icmp->close = icmpclose;
 496         icmp->rcv = icmpiput;
 497         icmp->stats = icmpstats;
 498         icmp->ctl = nil;
 499         icmp->advise = icmpadvise;
 500         icmp->gc = nil;
 501         icmp->ipproto = IP_ICMPPROTO;
 502         icmp->nc = 128;
 503         icmp->ptclsize = 0;
 504
 505         Fsproto(fs, icmp);
 506 }