slirp/ip6_icmp.c

   1 /*
   2  * Copyright (c) 2013
   3  * Guillaume Subiron, Yann Bordenave, Serigne Modou Wagne.
   4  */
   5
   6 #include "qemu/osdep.h"
   7 #include "slirp.h"
   8 #include "ip6_icmp.h"
   9 #include "qemu/timer.h"
  10 #include "qemu/error-report.h"
  11 #include "qemu/log.h"
  12
  13 #define NDP_Interval g_rand_int_range(slirp->grand, \
  14         NDP_MinRtrAdvInterval, NDP_MaxRtrAdvInterval)
  15
  16 static void ra_timer_handler(void *opaque)
  17 {
  18     Slirp *slirp = opaque;
  19     timer_mod(slirp->ra_timer,
  20               qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + NDP_Interval);
  21     ndp_send_ra(slirp);
  22 }
  23
  24 void icmp6_init(Slirp *slirp)
  25 {
  26     if (!slirp->in6_enabled) {
  27         return;
  28     }
  29
  30     slirp->ra_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, ra_timer_handler, slirp);
  31     timer_mod(slirp->ra_timer,
  32               qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + NDP_Interval);
  33 }
  34
  35 void icmp6_cleanup(Slirp *slirp)
  36 {
  37     if (!slirp->in6_enabled) {
  38         return;
  39     }
  40
  41     timer_del(slirp->ra_timer);
  42     timer_free(slirp->ra_timer);
  43 }
  44
  45 static void icmp6_send_echoreply(struct mbuf *m, Slirp *slirp, struct ip6 *ip,
  46         struct icmp6 *icmp)
  47 {
  48     struct mbuf *t = m_get(slirp);
  49     t->m_len = sizeof(struct ip6) + ntohs(ip->ip_pl);
  50     memcpy(t->m_data, m->m_data, t->m_len);
  51
  52     /* IPv6 Packet */
  53     struct ip6 *rip = mtod(t, struct ip6 *);
  54     rip->ip_dst = ip->ip_src;
  55     rip->ip_src = ip->ip_dst;
  56
  57     /* ICMPv6 packet */
  58     t->m_data += sizeof(struct ip6);
  59     struct icmp6 *ricmp = mtod(t, struct icmp6 *);
  60     ricmp->icmp6_type = ICMP6_ECHO_REPLY;
  61     ricmp->icmp6_cksum = 0;
  62
  63     /* Checksum */
  64     t->m_data -= sizeof(struct ip6);
  65     ricmp->icmp6_cksum = ip6_cksum(t);
  66
  67     ip6_output(NULL, t, 0);
  68 }
  69
  70 void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code)
  71 {
  72     Slirp *slirp = m->slirp;
  73     struct mbuf *t;
  74     struct ip6 *ip = mtod(m, struct ip6 *);
  75
  76     DEBUG_CALL("icmp6_send_error");
  77     DEBUG_ARGS((dfd, " type = %d, code = %d\n", type, code));
  78
  79     if (IN6_IS_ADDR_MULTICAST(&ip->ip_src) ||
  80             IN6_IS_ADDR_UNSPECIFIED(&ip->ip_src)) {
  81         /* TODO icmp error? */
  82         return;
  83     }
  84
  85     t = m_get(slirp);
  86
  87     /* IPv6 packet */
  88     struct ip6 *rip = mtod(t, struct ip6 *);
  89     rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;
  90     rip->ip_dst = ip->ip_src;
  91 #if !defined(_WIN32) || (_WIN32_WINNT >= 0x0600)
  92     char addrstr[INET6_ADDRSTRLEN];
  93     inet_ntop(AF_INET6, &rip->ip_dst, addrstr, INET6_ADDRSTRLEN);
  94     DEBUG_ARG("target = %s", addrstr);
  95 #endif
  96
  97     rip->ip_nh = IPPROTO_ICMPV6;
  98     const int error_data_len = min(m->m_len,
  99             IF_MTU - (sizeof(struct ip6) + ICMP6_ERROR_MINLEN));
 100     rip->ip_pl = htons(ICMP6_ERROR_MINLEN + error_data_len);
 101     t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
 102
 103     /* ICMPv6 packet */
 104     t->m_data += sizeof(struct ip6);
 105     struct icmp6 *ricmp = mtod(t, struct icmp6 *);
 106     ricmp->icmp6_type = type;
 107     ricmp->icmp6_code = code;
 108     ricmp->icmp6_cksum = 0;
 109
 110     switch (type) {
 111     case ICMP6_UNREACH:
 112     case ICMP6_TIMXCEED:
 113         ricmp->icmp6_err.unused = 0;
 114         break;
 115     case ICMP6_TOOBIG:
 116         ricmp->icmp6_err.mtu = htonl(IF_MTU);
 117         break;
 118     case ICMP6_PARAMPROB:
 119         /* TODO: Handle this case */
 120         break;
 121     default:
 122         g_assert_not_reached();
 123         break;
 124     }
 125     t->m_data += ICMP6_ERROR_MINLEN;
 126     memcpy(t->m_data, m->m_data, error_data_len);
 127
 128     /* Checksum */
 129     t->m_data -= ICMP6_ERROR_MINLEN;
 130     t->m_data -= sizeof(struct ip6);
 131     ricmp->icmp6_cksum = ip6_cksum(t);
 132
 133     ip6_output(NULL, t, 0);
 134 }
 135
 136 /*
 137  * Send NDP Router Advertisement
 138  */
 139 void ndp_send_ra(Slirp *slirp)
 140 {
 141     DEBUG_CALL("ndp_send_ra");
 142
 143     /* Build IPv6 packet */
 144     struct mbuf *t = m_get(slirp);
 145     struct ip6 *rip = mtod(t, struct ip6 *);
 146     rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;
 147     rip->ip_dst = (struct in6_addr)ALLNODES_MULTICAST;
 148     rip->ip_nh = IPPROTO_ICMPV6;
 149     rip->ip_pl = htons(ICMP6_NDP_RA_MINLEN
 150                         + NDPOPT_LINKLAYER_LEN
 151                         + NDPOPT_PREFIXINFO_LEN);
 152     t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
 153
 154     /* Build ICMPv6 packet */
 155     t->m_data += sizeof(struct ip6);
 156     struct icmp6 *ricmp = mtod(t, struct icmp6 *);
 157     ricmp->icmp6_type = ICMP6_NDP_RA;
 158     ricmp->icmp6_code = 0;
 159     ricmp->icmp6_cksum = 0;
 160
 161     /* NDP */
 162     ricmp->icmp6_nra.chl = NDP_AdvCurHopLimit;
 163     ricmp->icmp6_nra.M = NDP_AdvManagedFlag;
 164     ricmp->icmp6_nra.O = NDP_AdvOtherConfigFlag;
 165     ricmp->icmp6_nra.reserved = 0;
 166     ricmp->icmp6_nra.lifetime = htons(NDP_AdvDefaultLifetime);
 167     ricmp->icmp6_nra.reach_time = htonl(NDP_AdvReachableTime);
 168     ricmp->icmp6_nra.retrans_time = htonl(NDP_AdvRetransTime);
 169
 170     /* Source link-layer address (NDP option) */
 171     t->m_data += ICMP6_NDP_RA_MINLEN;
 172     struct ndpopt *opt = mtod(t, struct ndpopt *);
 173     opt->ndpopt_type = NDPOPT_LINKLAYER_SOURCE;
 174     opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
 175     in6_compute_ethaddr(rip->ip_src, opt->ndpopt_linklayer);
 176
 177     /* Prefix information (NDP option) */
 178     t->m_data += NDPOPT_LINKLAYER_LEN;
 179     struct ndpopt *opt2 = mtod(t, struct ndpopt *);
 180     opt2->ndpopt_type = NDPOPT_PREFIX_INFO;
 181     opt2->ndpopt_len = NDPOPT_PREFIXINFO_LEN / 8;
 182     opt2->ndpopt_prefixinfo.prefix_length = slirp->vprefix_len;
 183     opt2->ndpopt_prefixinfo.L = 1;
 184     opt2->ndpopt_prefixinfo.A = 1;
 185     opt2->ndpopt_prefixinfo.reserved1 = 0;
 186     opt2->ndpopt_prefixinfo.valid_lt = htonl(NDP_AdvValidLifetime);
 187     opt2->ndpopt_prefixinfo.pref_lt = htonl(NDP_AdvPrefLifetime);
 188     opt2->ndpopt_prefixinfo.reserved2 = 0;
 189     opt2->ndpopt_prefixinfo.prefix = slirp->vprefix_addr6;
 190
 191     /* ICMPv6 Checksum */
 192     t->m_data -= NDPOPT_LINKLAYER_LEN;
 193     t->m_data -= ICMP6_NDP_RA_MINLEN;
 194     t->m_data -= sizeof(struct ip6);
 195     ricmp->icmp6_cksum = ip6_cksum(t);
 196
 197     ip6_output(NULL, t, 0);
 198 }
 199
 200 /*
 201  * Send NDP Neighbor Solitication
 202  */
 203 void ndp_send_ns(Slirp *slirp, struct in6_addr addr)
 204 {
 205     DEBUG_CALL("ndp_send_ns");
 206 #if !defined(_WIN32) || (_WIN32_WINNT >= 0x0600)
 207     char addrstr[INET6_ADDRSTRLEN];
 208     inet_ntop(AF_INET6, &addr, addrstr, INET6_ADDRSTRLEN);
 209     DEBUG_ARG("target = %s", addrstr);
 210 #endif
 211
 212     /* Build IPv6 packet */
 213     struct mbuf *t = m_get(slirp);
 214     struct ip6 *rip = mtod(t, struct ip6 *);
 215     rip->ip_src = slirp->vhost_addr6;
 216     rip->ip_dst = (struct in6_addr)SOLICITED_NODE_PREFIX;
 217     memcpy(&rip->ip_dst.s6_addr[13], &addr.s6_addr[13], 3);
 218     rip->ip_nh = IPPROTO_ICMPV6;
 219     rip->ip_pl = htons(ICMP6_NDP_NS_MINLEN + NDPOPT_LINKLAYER_LEN);
 220     t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
 221
 222     /* Build ICMPv6 packet */
 223     t->m_data += sizeof(struct ip6);
 224     struct icmp6 *ricmp = mtod(t, struct icmp6 *);
 225     ricmp->icmp6_type = ICMP6_NDP_NS;
 226     ricmp->icmp6_code = 0;
 227     ricmp->icmp6_cksum = 0;
 228
 229     /* NDP */
 230     ricmp->icmp6_nns.reserved = 0;
 231     ricmp->icmp6_nns.target = addr;
 232
 233     /* Build NDP option */
 234     t->m_data += ICMP6_NDP_NS_MINLEN;
 235     struct ndpopt *opt = mtod(t, struct ndpopt *);
 236     opt->ndpopt_type = NDPOPT_LINKLAYER_SOURCE;
 237     opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
 238     in6_compute_ethaddr(slirp->vhost_addr6, opt->ndpopt_linklayer);
 239
 240     /* ICMPv6 Checksum */
 241     t->m_data -= ICMP6_NDP_NA_MINLEN;
 242     t->m_data -= sizeof(struct ip6);
 243     ricmp->icmp6_cksum = ip6_cksum(t);
 244
 245     ip6_output(NULL, t, 1);
 246 }
 247
 248 /*
 249  * Send NDP Neighbor Advertisement
 250  */
 251 static void ndp_send_na(Slirp *slirp, struct ip6 *ip, struct icmp6 *icmp)
 252 {
 253     /* Build IPv6 packet */
 254     struct mbuf *t = m_get(slirp);
 255     struct ip6 *rip = mtod(t, struct ip6 *);
 256     rip->ip_src = icmp->icmp6_nns.target;
 257     if (IN6_IS_ADDR_UNSPECIFIED(&ip->ip_src)) {
 258         rip->ip_dst = (struct in6_addr)ALLNODES_MULTICAST;
 259     } else {
 260         rip->ip_dst = ip->ip_src;
 261     }
 262     rip->ip_nh = IPPROTO_ICMPV6;
 263     rip->ip_pl = htons(ICMP6_NDP_NA_MINLEN
 264                         + NDPOPT_LINKLAYER_LEN);
 265     t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
 266
 267     /* Build ICMPv6 packet */
 268     t->m_data += sizeof(struct ip6);
 269     struct icmp6 *ricmp = mtod(t, struct icmp6 *);
 270     ricmp->icmp6_type = ICMP6_NDP_NA;
 271     ricmp->icmp6_code = 0;
 272     ricmp->icmp6_cksum = 0;
 273
 274     /* NDP */
 275     ricmp->icmp6_nna.R = NDP_IsRouter;
 276     ricmp->icmp6_nna.S = !IN6_IS_ADDR_MULTICAST(&rip->ip_dst);
 277     ricmp->icmp6_nna.O = 1;
 278     ricmp->icmp6_nna.reserved_hi = 0;
 279     ricmp->icmp6_nna.reserved_lo = 0;
 280     ricmp->icmp6_nna.target = icmp->icmp6_nns.target;
 281
 282     /* Build NDP option */
 283     t->m_data += ICMP6_NDP_NA_MINLEN;
 284     struct ndpopt *opt = mtod(t, struct ndpopt *);
 285     opt->ndpopt_type = NDPOPT_LINKLAYER_TARGET;
 286     opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
 287     in6_compute_ethaddr(ricmp->icmp6_nna.target,
 288                     opt->ndpopt_linklayer);
 289
 290     /* ICMPv6 Checksum */
 291     t->m_data -= ICMP6_NDP_NA_MINLEN;
 292     t->m_data -= sizeof(struct ip6);
 293     ricmp->icmp6_cksum = ip6_cksum(t);
 294
 295     ip6_output(NULL, t, 0);
 296 }
 297
 298 /*
 299  * Process a NDP message
 300  */
 301 static void ndp_input(struct mbuf *m, Slirp *slirp, struct ip6 *ip,
 302         struct icmp6 *icmp)
 303 {
 304     m->m_len += ETH_HLEN;
 305     m->m_data -= ETH_HLEN;
 306     struct ethhdr *eth = mtod(m, struct ethhdr *);
 307     m->m_len -= ETH_HLEN;
 308     m->m_data += ETH_HLEN;
 309
 310     switch (icmp->icmp6_type) {
 311     case ICMP6_NDP_RS:
 312         DEBUG_CALL(" type = Router Solicitation");
 313         if (ip->ip_hl == 255
 314                 && icmp->icmp6_code == 0
 315                 && ntohs(ip->ip_pl) >= ICMP6_NDP_RS_MINLEN) {
 316             /* Gratuitous NDP */
 317             ndp_table_add(slirp, ip->ip_src, eth->h_source);
 318
 319             ndp_send_ra(slirp);
 320         }
 321         break;
 322
 323     case ICMP6_NDP_RA:
 324         DEBUG_CALL(" type = Router Advertisement");
 325         qemu_log_mask(LOG_GUEST_ERROR,
 326                 "Warning: guest sent NDP RA, but shouldn't");
 327         break;
 328
 329     case ICMP6_NDP_NS:
 330         DEBUG_CALL(" type = Neighbor Solicitation");
 331         if (ip->ip_hl == 255
 332                 && icmp->icmp6_code == 0
 333                 && !IN6_IS_ADDR_MULTICAST(&icmp->icmp6_nns.target)
 334                 && ntohs(ip->ip_pl) >= ICMP6_NDP_NS_MINLEN
 335                 && (!IN6_IS_ADDR_UNSPECIFIED(&ip->ip_src)
 336                     || in6_solicitednode_multicast(&ip->ip_dst))) {
 337             if (in6_equal_host(&icmp->icmp6_nns.target)) {
 338                 /* Gratuitous NDP */
 339                 ndp_table_add(slirp, ip->ip_src, eth->h_source);
 340                 ndp_send_na(slirp, ip, icmp);
 341             }
 342         }
 343         break;
 344
 345     case ICMP6_NDP_NA:
 346         DEBUG_CALL(" type = Neighbor Advertisement");
 347         if (ip->ip_hl == 255
 348                 && icmp->icmp6_code == 0
 349                 && ntohs(ip->ip_pl) >= ICMP6_NDP_NA_MINLEN
 350                 && !IN6_IS_ADDR_MULTICAST(&icmp->icmp6_nna.target)
 351                 && (!IN6_IS_ADDR_MULTICAST(&ip->ip_dst)
 352                     || icmp->icmp6_nna.S == 0)) {
 353             ndp_table_add(slirp, ip->ip_src, eth->h_source);
 354         }
 355         break;
 356
 357     case ICMP6_NDP_REDIRECT:
 358         DEBUG_CALL(" type = Redirect");
 359         qemu_log_mask(LOG_GUEST_ERROR,
 360                 "Warning: guest sent NDP REDIRECT, but shouldn't");
 361         break;
 362     }
 363 }
 364
 365 /*
 366  * Process a received ICMPv6 message.
 367  */
 368 void icmp6_input(struct mbuf *m)
 369 {
 370     struct icmp6 *icmp;
 371     struct ip6 *ip = mtod(m, struct ip6 *);
 372     Slirp *slirp = m->slirp;
 373     int hlen = sizeof(struct ip6);
 374
 375     DEBUG_CALL("icmp6_input");
 376     DEBUG_ARG("m = %lx", (long) m);
 377     DEBUG_ARG("m_len = %d", m->m_len);
 378
 379     if (ntohs(ip->ip_pl) < ICMP6_MINLEN) {
 380         goto end;
 381     }
 382
 383     if (ip6_cksum(m)) {
 384         goto end;
 385     }
 386
 387     m->m_len -= hlen;
 388     m->m_data += hlen;
 389     icmp = mtod(m, struct icmp6 *);
 390     m->m_len += hlen;
 391     m->m_data -= hlen;
 392
 393     DEBUG_ARG("icmp6_type = %d", icmp->icmp6_type);
 394     switch (icmp->icmp6_type) {
 395     case ICMP6_ECHO_REQUEST:
 396         if (in6_equal_host(&ip->ip_dst)) {
 397             icmp6_send_echoreply(m, slirp, ip, icmp);
 398         } else {
 399             /* TODO */
 400             error_report("external icmpv6 not supported yet");
 401         }
 402         break;
 403
 404     case ICMP6_NDP_RS:
 405     case ICMP6_NDP_RA:
 406     case ICMP6_NDP_NS:
 407     case ICMP6_NDP_NA:
 408     case ICMP6_NDP_REDIRECT:
 409         ndp_input(m, slirp, ip, icmp);
 410         break;
 411
 412     case ICMP6_UNREACH:
 413     case ICMP6_TOOBIG:
 414     case ICMP6_TIMXCEED:
 415     case ICMP6_PARAMPROB:
 416         /* XXX? report error? close socket? */
 417     default:
 418         break;
 419     }
 420
 421 end:
 422     m_free(m);
 423 }