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_full(NULL, QEMU_CLOCK_VIRTUAL,
  31                                      SCALE_MS, QEMU_TIMER_ATTR_EXTERNAL,
  32                                      ra_timer_handler, slirp);
  33     timer_mod(slirp->ra_timer,
  34               qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + NDP_Interval);
  35 }
  36
  37 void icmp6_cleanup(Slirp *slirp)
  38 {
  39     if (!slirp->in6_enabled) {
  40         return;
  41     }
  42
  43     timer_del(slirp->ra_timer);
  44     timer_free(slirp->ra_timer);
  45 }
  46
  47 static void icmp6_send_echoreply(struct mbuf *m, Slirp *slirp, struct ip6 *ip,
  48         struct icmp6 *icmp)
  49 {
  50     struct mbuf *t = m_get(slirp);
  51     t->m_len = sizeof(struct ip6) + ntohs(ip->ip_pl);
  52     memcpy(t->m_data, m->m_data, t->m_len);
  53
  54     /* IPv6 Packet */
  55     struct ip6 *rip = mtod(t, struct ip6 *);
  56     rip->ip_dst = ip->ip_src;
  57     rip->ip_src = ip->ip_dst;
  58
  59     /* ICMPv6 packet */
  60     t->m_data += sizeof(struct ip6);
  61     struct icmp6 *ricmp = mtod(t, struct icmp6 *);
  62     ricmp->icmp6_type = ICMP6_ECHO_REPLY;
  63     ricmp->icmp6_cksum = 0;
  64
  65     /* Checksum */
  66     t->m_data -= sizeof(struct ip6);
  67     ricmp->icmp6_cksum = ip6_cksum(t);
  68
  69     ip6_output(NULL, t, 0);
  70 }
  71
  72 void icmp6_send_error(struct mbuf *m, uint8_t type, uint8_t code)
  73 {
  74     Slirp *slirp = m->slirp;
  75     struct mbuf *t;
  76     struct ip6 *ip = mtod(m, struct ip6 *);
  77     char addrstr[INET6_ADDRSTRLEN];
  78
  79     DEBUG_CALL("icmp6_send_error");
  80     DEBUG_ARGS(" type = %d, code = %d\n", type, code);
  81
  82     if (IN6_IS_ADDR_MULTICAST(&ip->ip_src) ||
  83             in6_zero(&ip->ip_src)) {
  84         /* TODO icmp error? */
  85         return;
  86     }
  87
  88     t = m_get(slirp);
  89
  90     /* IPv6 packet */
  91     struct ip6 *rip = mtod(t, struct ip6 *);
  92     rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;
  93     rip->ip_dst = ip->ip_src;
  94     inet_ntop(AF_INET6, &rip->ip_dst, addrstr, INET6_ADDRSTRLEN);
  95     DEBUG_ARG("target = %s", addrstr);
  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     size_t pl_size = 0;
 147     struct in6_addr addr;
 148     uint32_t scope_id;
 149
 150     rip->ip_src = (struct in6_addr)LINKLOCAL_ADDR;
 151     rip->ip_dst = (struct in6_addr)ALLNODES_MULTICAST;
 152     rip->ip_nh = IPPROTO_ICMPV6;
 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     t->m_data += ICMP6_NDP_RA_MINLEN;
 170     pl_size += ICMP6_NDP_RA_MINLEN;
 171
 172     /* Source link-layer address (NDP option) */
 173     struct ndpopt *opt = mtod(t, struct ndpopt *);
 174     opt->ndpopt_type = NDPOPT_LINKLAYER_SOURCE;
 175     opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
 176     in6_compute_ethaddr(rip->ip_src, opt->ndpopt_linklayer);
 177     t->m_data += NDPOPT_LINKLAYER_LEN;
 178     pl_size += NDPOPT_LINKLAYER_LEN;
 179
 180     /* Prefix information (NDP option) */
 181     struct ndpopt *opt2 = mtod(t, struct ndpopt *);
 182     opt2->ndpopt_type = NDPOPT_PREFIX_INFO;
 183     opt2->ndpopt_len = NDPOPT_PREFIXINFO_LEN / 8;
 184     opt2->ndpopt_prefixinfo.prefix_length = slirp->vprefix_len;
 185     opt2->ndpopt_prefixinfo.L = 1;
 186     opt2->ndpopt_prefixinfo.A = 1;
 187     opt2->ndpopt_prefixinfo.reserved1 = 0;
 188     opt2->ndpopt_prefixinfo.valid_lt = htonl(NDP_AdvValidLifetime);
 189     opt2->ndpopt_prefixinfo.pref_lt = htonl(NDP_AdvPrefLifetime);
 190     opt2->ndpopt_prefixinfo.reserved2 = 0;
 191     opt2->ndpopt_prefixinfo.prefix = slirp->vprefix_addr6;
 192     t->m_data += NDPOPT_PREFIXINFO_LEN;
 193     pl_size += NDPOPT_PREFIXINFO_LEN;
 194
 195     /* Prefix information (NDP option) */
 196     if (get_dns6_addr(&addr, &scope_id) >= 0) {
 197         /* Host system does have an IPv6 DNS server, announce our proxy.  */
 198         struct ndpopt *opt3 = mtod(t, struct ndpopt *);
 199         opt3->ndpopt_type = NDPOPT_RDNSS;
 200         opt3->ndpopt_len = NDPOPT_RDNSS_LEN / 8;
 201         opt3->ndpopt_rdnss.reserved = 0;
 202         opt3->ndpopt_rdnss.lifetime = htonl(2 * NDP_MaxRtrAdvInterval);
 203         opt3->ndpopt_rdnss.addr = slirp->vnameserver_addr6;
 204         t->m_data += NDPOPT_RDNSS_LEN;
 205         pl_size += NDPOPT_RDNSS_LEN;
 206     }
 207
 208     rip->ip_pl = htons(pl_size);
 209     t->m_data -= sizeof(struct ip6) + pl_size;
 210     t->m_len = sizeof(struct ip6) + pl_size;
 211
 212     /* ICMPv6 Checksum */
 213     ricmp->icmp6_cksum = ip6_cksum(t);
 214
 215     ip6_output(NULL, t, 0);
 216 }
 217
 218 /*
 219  * Send NDP Neighbor Solitication
 220  */
 221 void ndp_send_ns(Slirp *slirp, struct in6_addr addr)
 222 {
 223     char addrstr[INET6_ADDRSTRLEN];
 224
 225     inet_ntop(AF_INET6, &addr, addrstr, INET6_ADDRSTRLEN);
 226
 227     DEBUG_CALL("ndp_send_ns");
 228     DEBUG_ARG("target = %s", addrstr);
 229
 230     /* Build IPv6 packet */
 231     struct mbuf *t = m_get(slirp);
 232     struct ip6 *rip = mtod(t, struct ip6 *);
 233     rip->ip_src = slirp->vhost_addr6;
 234     rip->ip_dst = (struct in6_addr)SOLICITED_NODE_PREFIX;
 235     memcpy(&rip->ip_dst.s6_addr[13], &addr.s6_addr[13], 3);
 236     rip->ip_nh = IPPROTO_ICMPV6;
 237     rip->ip_pl = htons(ICMP6_NDP_NS_MINLEN + NDPOPT_LINKLAYER_LEN);
 238     t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
 239
 240     /* Build ICMPv6 packet */
 241     t->m_data += sizeof(struct ip6);
 242     struct icmp6 *ricmp = mtod(t, struct icmp6 *);
 243     ricmp->icmp6_type = ICMP6_NDP_NS;
 244     ricmp->icmp6_code = 0;
 245     ricmp->icmp6_cksum = 0;
 246
 247     /* NDP */
 248     ricmp->icmp6_nns.reserved = 0;
 249     ricmp->icmp6_nns.target = addr;
 250
 251     /* Build NDP option */
 252     t->m_data += ICMP6_NDP_NS_MINLEN;
 253     struct ndpopt *opt = mtod(t, struct ndpopt *);
 254     opt->ndpopt_type = NDPOPT_LINKLAYER_SOURCE;
 255     opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
 256     in6_compute_ethaddr(slirp->vhost_addr6, opt->ndpopt_linklayer);
 257
 258     /* ICMPv6 Checksum */
 259     t->m_data -= ICMP6_NDP_NA_MINLEN;
 260     t->m_data -= sizeof(struct ip6);
 261     ricmp->icmp6_cksum = ip6_cksum(t);
 262
 263     ip6_output(NULL, t, 1);
 264 }
 265
 266 /*
 267  * Send NDP Neighbor Advertisement
 268  */
 269 static void ndp_send_na(Slirp *slirp, struct ip6 *ip, struct icmp6 *icmp)
 270 {
 271     /* Build IPv6 packet */
 272     struct mbuf *t = m_get(slirp);
 273     struct ip6 *rip = mtod(t, struct ip6 *);
 274     rip->ip_src = icmp->icmp6_nns.target;
 275     if (in6_zero(&ip->ip_src)) {
 276         rip->ip_dst = (struct in6_addr)ALLNODES_MULTICAST;
 277     } else {
 278         rip->ip_dst = ip->ip_src;
 279     }
 280     rip->ip_nh = IPPROTO_ICMPV6;
 281     rip->ip_pl = htons(ICMP6_NDP_NA_MINLEN
 282                         + NDPOPT_LINKLAYER_LEN);
 283     t->m_len = sizeof(struct ip6) + ntohs(rip->ip_pl);
 284
 285     /* Build ICMPv6 packet */
 286     t->m_data += sizeof(struct ip6);
 287     struct icmp6 *ricmp = mtod(t, struct icmp6 *);
 288     ricmp->icmp6_type = ICMP6_NDP_NA;
 289     ricmp->icmp6_code = 0;
 290     ricmp->icmp6_cksum = 0;
 291
 292     /* NDP */
 293     ricmp->icmp6_nna.R = NDP_IsRouter;
 294     ricmp->icmp6_nna.S = !IN6_IS_ADDR_MULTICAST(&rip->ip_dst);
 295     ricmp->icmp6_nna.O = 1;
 296     ricmp->icmp6_nna.reserved_hi = 0;
 297     ricmp->icmp6_nna.reserved_lo = 0;
 298     ricmp->icmp6_nna.target = icmp->icmp6_nns.target;
 299
 300     /* Build NDP option */
 301     t->m_data += ICMP6_NDP_NA_MINLEN;
 302     struct ndpopt *opt = mtod(t, struct ndpopt *);
 303     opt->ndpopt_type = NDPOPT_LINKLAYER_TARGET;
 304     opt->ndpopt_len = NDPOPT_LINKLAYER_LEN / 8;
 305     in6_compute_ethaddr(ricmp->icmp6_nna.target,
 306                     opt->ndpopt_linklayer);
 307
 308     /* ICMPv6 Checksum */
 309     t->m_data -= ICMP6_NDP_NA_MINLEN;
 310     t->m_data -= sizeof(struct ip6);
 311     ricmp->icmp6_cksum = ip6_cksum(t);
 312
 313     ip6_output(NULL, t, 0);
 314 }
 315
 316 /*
 317  * Process a NDP message
 318  */
 319 static void ndp_input(struct mbuf *m, Slirp *slirp, struct ip6 *ip,
 320         struct icmp6 *icmp)
 321 {
 322     m->m_len += ETH_HLEN;
 323     m->m_data -= ETH_HLEN;
 324     struct ethhdr *eth = mtod(m, struct ethhdr *);
 325     m->m_len -= ETH_HLEN;
 326     m->m_data += ETH_HLEN;
 327
 328     switch (icmp->icmp6_type) {
 329     case ICMP6_NDP_RS:
 330         DEBUG_CALL(" type = Router Solicitation");
 331         if (ip->ip_hl == 255
 332                 && icmp->icmp6_code == 0
 333                 && ntohs(ip->ip_pl) >= ICMP6_NDP_RS_MINLEN) {
 334             /* Gratuitous NDP */
 335             ndp_table_add(slirp, ip->ip_src, eth->h_source);
 336
 337             ndp_send_ra(slirp);
 338         }
 339         break;
 340
 341     case ICMP6_NDP_RA:
 342         DEBUG_CALL(" type = Router Advertisement");
 343         slirp->cb->guest_error("Warning: guest sent NDP RA, but shouldn't");
 344         break;
 345
 346     case ICMP6_NDP_NS:
 347         DEBUG_CALL(" type = Neighbor Solicitation");
 348         if (ip->ip_hl == 255
 349                 && icmp->icmp6_code == 0
 350                 && !IN6_IS_ADDR_MULTICAST(&icmp->icmp6_nns.target)
 351                 && ntohs(ip->ip_pl) >= ICMP6_NDP_NS_MINLEN
 352                 && (!in6_zero(&ip->ip_src)
 353                     || in6_solicitednode_multicast(&ip->ip_dst))) {
 354             if (in6_equal_host(&icmp->icmp6_nns.target)) {
 355                 /* Gratuitous NDP */
 356                 ndp_table_add(slirp, ip->ip_src, eth->h_source);
 357                 ndp_send_na(slirp, ip, icmp);
 358             }
 359         }
 360         break;
 361
 362     case ICMP6_NDP_NA:
 363         DEBUG_CALL(" type = Neighbor Advertisement");
 364         if (ip->ip_hl == 255
 365                 && icmp->icmp6_code == 0
 366                 && ntohs(ip->ip_pl) >= ICMP6_NDP_NA_MINLEN
 367                 && !IN6_IS_ADDR_MULTICAST(&icmp->icmp6_nna.target)
 368                 && (!IN6_IS_ADDR_MULTICAST(&ip->ip_dst)
 369                     || icmp->icmp6_nna.S == 0)) {
 370             ndp_table_add(slirp, ip->ip_src, eth->h_source);
 371         }
 372         break;
 373
 374     case ICMP6_NDP_REDIRECT:
 375         DEBUG_CALL(" type = Redirect");
 376         slirp->cb->guest_error(
 377             "Warning: guest sent NDP REDIRECT, but shouldn't");
 378         break;
 379     }
 380 }
 381
 382 /*
 383  * Process a received ICMPv6 message.
 384  */
 385 void icmp6_input(struct mbuf *m)
 386 {
 387     struct icmp6 *icmp;
 388     struct ip6 *ip = mtod(m, struct ip6 *);
 389     Slirp *slirp = m->slirp;
 390     int hlen = sizeof(struct ip6);
 391
 392     DEBUG_CALL("icmp6_input");
 393     DEBUG_ARG("m = %lx", (long) m);
 394     DEBUG_ARG("m_len = %d", m->m_len);
 395
 396     if (ntohs(ip->ip_pl) < ICMP6_MINLEN) {
 397         goto end;
 398     }
 399
 400     if (ip6_cksum(m)) {
 401         goto end;
 402     }
 403
 404     m->m_len -= hlen;
 405     m->m_data += hlen;
 406     icmp = mtod(m, struct icmp6 *);
 407     m->m_len += hlen;
 408     m->m_data -= hlen;
 409
 410     DEBUG_ARG("icmp6_type = %d", icmp->icmp6_type);
 411     switch (icmp->icmp6_type) {
 412     case ICMP6_ECHO_REQUEST:
 413         if (in6_equal_host(&ip->ip_dst)) {
 414             icmp6_send_echoreply(m, slirp, ip, icmp);
 415         } else {
 416             /* TODO */
 417             g_critical("external icmpv6 not supported yet");
 418         }
 419         break;
 420
 421     case ICMP6_NDP_RS:
 422     case ICMP6_NDP_RA:
 423     case ICMP6_NDP_NS:
 424     case ICMP6_NDP_NA:
 425     case ICMP6_NDP_REDIRECT:
 426         ndp_input(m, slirp, ip, icmp);
 427         break;
 428
 429     case ICMP6_UNREACH:
 430     case ICMP6_TOOBIG:
 431     case ICMP6_TIMXCEED:
 432     case ICMP6_PARAMPROB:
 433         /* XXX? report error? close socket? */
 434     default:
 435         break;
 436     }
 437
 438 end:
 439     m_free(m);
 440 }