zebra/irdp_packet.c

   1 /*
   2  *
   3  * Copyright (C) 2000  Robert Olsson.
   4  * Swedish University of Agricultural Sciences
   5  *
   6  * This file is part of GNU Zebra.
   7  *
   8  * GNU Zebra is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 2, or (at your option) any
  11  * later version.
  12  *
  13  * GNU Zebra is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; see the file COPYING; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 /*
  24  * This work includes work with the following copywrite:
  25  *
  26  * Copyright (C) 1997, 2000 Kunihiro Ishiguro
  27  *
  28  */
  29
  30 /*
  31  * Thanks to Jens Laas at Swedish University of Agricultural Sciences
  32  * for reviewing and tests.
  33  */
  34
  35
  36 #include <zebra.h>
  37 #include <netinet/ip_icmp.h>
  38
  39 #include "checksum.h"
  40 #include "command.h"
  41 #include "connected.h"
  42 #include "if.h"
  43 #include "ioctl.h"
  44 #include "log.h"
  45 #include "log.h"
  46 #include "memory.h"
  47 #include "prefix.h"
  48 #include "sockopt.h"
  49 #include "sockunion.h"
  50 #include "sockunion.h"
  51 #include "stream.h"
  52 #include "thread.h"
  53 #include "vty.h"
  54 #include "zclient.h"
  55 #include "lib_errors.h"
  56
  57 #include "zebra_memory.h"
  58 #include "zebra/interface.h"
  59 #include "zebra/rtadv.h"
  60 #include "zebra/rib.h"
  61 #include "zebra/zserv.h"
  62 #include "zebra/redistribute.h"
  63 #include "zebra/irdp.h"
  64 #include "zebra/zebra_errors.h"
  65
  66
  67 /* GLOBAL VARS */
  68
  69 int irdp_sock = -1;
  70
  71 extern struct thread *t_irdp_raw;
  72
  73 static void parse_irdp_packet(char *p, int len, struct interface *ifp)
  74 {
  75         struct ip *ip = (struct ip *)p;
  76         struct icmphdr *icmp;
  77         struct in_addr src;
  78         int ip_hlen, iplen, datalen;
  79         struct zebra_if *zi;
  80         struct irdp_interface *irdp;
  81
  82         zi = ifp->info;
  83         if (!zi)
  84                 return;
  85
  86         irdp = zi->irdp;
  87         if (!irdp)
  88                 return;
  89
  90         ip_hlen = ip->ip_hl << 2;
  91
  92         sockopt_iphdrincl_swab_systoh(ip);
  93
  94         iplen = ip->ip_len;
  95         datalen = len - ip_hlen;
  96         src = ip->ip_src;
  97
  98         if (len != iplen) {
  99                 flog_err(EC_ZEBRA_IRDP_LEN_MISMATCH,
 100                          "IRDP: RX length doesn't match IP length");
 101                 return;
 102         }
 103
 104         if (iplen < ICMP_MINLEN) {
 105                 flog_err(EC_ZEBRA_IRDP_LEN_MISMATCH,
 106                          "IRDP: RX ICMP packet too short from %s\n",
 107                          inet_ntoa(src));
 108                 return;
 109         }
 110
 111         /* XXX: RAW doesn't receive link-layer, surely? ??? */
 112         /* Check so we don't checksum packets longer than oure RX_BUF - (ethlen
 113          +
 114          len of IP-header) 14+20 */
 115         if (iplen > IRDP_RX_BUF - 34) {
 116                 flog_err(EC_ZEBRA_IRDP_LEN_MISMATCH,
 117                          "IRDP: RX ICMP packet too long from %s\n",
 118                          inet_ntoa(src));
 119                 return;
 120         }
 121
 122         icmp = (struct icmphdr *)(p + ip_hlen);
 123
 124         /* check icmp checksum */
 125         if (in_cksum(icmp, datalen) != icmp->checksum) {
 126                 flog_warn(
 127                         EC_ZEBRA_IRDP_BAD_CHECKSUM,
 128                         "IRDP: RX ICMP packet from %s. Bad checksum, silently ignored",
 129                         inet_ntoa(src));
 130                 return;
 131         }
 132
 133         /* Handle just only IRDP */
 134         if (!(icmp->type == ICMP_ROUTERADVERT
 135               || icmp->type == ICMP_ROUTERSOLICIT))
 136                 return;
 137
 138         if (icmp->code != 0) {
 139                 flog_warn(EC_ZEBRA_IRDP_BAD_TYPE_CODE,
 140                           "IRDP: RX packet type %d from %s. Bad ICMP type code,"
 141                           " silently ignored",
 142                           icmp->type, inet_ntoa(src));
 143                 return;
 144         }
 145
 146         if (!((ntohl(ip->ip_dst.s_addr) == INADDR_BROADCAST)
 147               && (irdp->flags & IF_BROADCAST))
 148             || (ntohl(ip->ip_dst.s_addr) == INADDR_ALLRTRS_GROUP
 149                 && !(irdp->flags & IF_BROADCAST))) {
 150                 flog_warn(
 151                         EC_ZEBRA_IRDP_BAD_RX_FLAGS,
 152                         "IRDP: RX illegal from %s to %s while %s operates in %s; Please correct settings\n",
 153                         inet_ntoa(src),
 154                         ntohl(ip->ip_dst.s_addr) == INADDR_ALLRTRS_GROUP
 155                                 ? "multicast"
 156                                 : inet_ntoa(ip->ip_dst),
 157                         ifp->name,
 158                         irdp->flags & IF_BROADCAST ? "broadcast" : "multicast");
 159                 return;
 160         }
 161
 162         switch (icmp->type) {
 163         case ICMP_ROUTERADVERT:
 164                 break;
 165
 166         case ICMP_ROUTERSOLICIT:
 167
 168                 if (irdp->flags & IF_DEBUG_MESSAGES)
 169                         zlog_debug("IRDP: RX Solicit on %s from %s\n",
 170                                    ifp->name, inet_ntoa(src));
 171
 172                 process_solicit(ifp);
 173                 break;
 174
 175         default:
 176                 flog_warn(
 177                         EC_ZEBRA_IRDP_BAD_TYPE,
 178                         "IRDP: RX type %d from %s. Bad ICMP type, silently ignored",
 179                         icmp->type, inet_ntoa(src));
 180         }
 181 }
 182
 183 static int irdp_recvmsg(int sock, uint8_t *buf, int size, int *ifindex)
 184 {
 185         struct msghdr msg;
 186         struct iovec iov;
 187         char adata[CMSG_SPACE(SOPT_SIZE_CMSG_PKTINFO_IPV4())];
 188         int ret;
 189
 190         memset(&msg, 0, sizeof(msg));
 191         msg.msg_name = (void *)0;
 192         msg.msg_namelen = 0;
 193         msg.msg_iov = &iov;
 194         msg.msg_iovlen = 1;
 195         msg.msg_control = (void *)adata;
 196         msg.msg_controllen = sizeof adata;
 197
 198         iov.iov_base = buf;
 199         iov.iov_len = size;
 200
 201         ret = recvmsg(sock, &msg, 0);
 202         if (ret < 0) {
 203                 flog_warn(EC_LIB_SOCKET, "IRDP: recvmsg: read error %s",
 204                           safe_strerror(errno));
 205                 return ret;
 206         }
 207
 208         if (msg.msg_flags & MSG_TRUNC) {
 209                 flog_warn(EC_LIB_SOCKET, "IRDP: recvmsg: truncated message");
 210                 return ret;
 211         }
 212         if (msg.msg_flags & MSG_CTRUNC) {
 213                 flog_warn(EC_LIB_SOCKET,
 214                           "IRDP: recvmsg: truncated control message");
 215                 return ret;
 216         }
 217
 218         *ifindex = getsockopt_ifindex(AF_INET, &msg);
 219
 220         return ret;
 221 }
 222
 223 int irdp_read_raw(struct thread *r)
 224 {
 225         struct interface *ifp;
 226         struct zebra_if *zi;
 227         struct irdp_interface *irdp;
 228         char buf[IRDP_RX_BUF];
 229         int ret, ifindex = 0;
 230
 231         int irdp_sock = THREAD_FD(r);
 232         t_irdp_raw = NULL;
 233         thread_add_read(zebrad.master, irdp_read_raw, NULL, irdp_sock,
 234                         &t_irdp_raw);
 235
 236         ret = irdp_recvmsg(irdp_sock, (uint8_t *)buf, IRDP_RX_BUF, &ifindex);
 237
 238         if (ret < 0)
 239                 flog_warn(EC_LIB_SOCKET, "IRDP: RX Error length = %d", ret);
 240
 241         ifp = if_lookup_by_index(ifindex, VRF_DEFAULT);
 242         if (!ifp)
 243                 return ret;
 244
 245         zi = ifp->info;
 246         if (!zi)
 247                 return ret;
 248
 249         irdp = zi->irdp;
 250         if (!irdp)
 251                 return ret;
 252
 253         if (!(irdp->flags & IF_ACTIVE)) {
 254
 255                 if (irdp->flags & IF_DEBUG_MISC)
 256                         zlog_debug("IRDP: RX ICMP for disabled interface %s\n",
 257                                    ifp->name);
 258                 return 0;
 259         }
 260
 261         if (irdp->flags & IF_DEBUG_PACKET) {
 262                 int i;
 263                 zlog_debug("IRDP: RX (idx %d) ", ifindex);
 264                 for (i = 0; i < ret; i++)
 265                         zlog_debug("IRDP: RX %x ", buf[i] & 0xFF);
 266         }
 267
 268         parse_irdp_packet(buf, ret, ifp);
 269
 270         return ret;
 271 }
 272
 273 void send_packet(struct interface *ifp, struct stream *s, uint32_t dst,
 274                  struct prefix *p, uint32_t ttl)
 275 {
 276         static struct sockaddr_in sockdst = {AF_INET};
 277         struct ip *ip;
 278         struct icmphdr *icmp;
 279         struct msghdr *msg;
 280         struct cmsghdr *cmsg;
 281         struct iovec iovector;
 282         char msgbuf[256];
 283         char buf[256];
 284         struct in_pktinfo *pktinfo;
 285         unsigned long src;
 286         uint8_t on;
 287
 288         if (!(ifp->flags & IFF_UP))
 289                 return;
 290
 291         if (p)
 292                 src = ntohl(p->u.prefix4.s_addr);
 293         else
 294                 src = 0; /* Is filled in */
 295
 296         ip = (struct ip *)buf;
 297         ip->ip_hl = sizeof(struct ip) >> 2;
 298         ip->ip_v = IPVERSION;
 299         ip->ip_tos = 0xC0;
 300         ip->ip_off = 0L;
 301         ip->ip_p = 1; /* IP_ICMP */
 302         ip->ip_ttl = ttl;
 303         ip->ip_src.s_addr = src;
 304         ip->ip_dst.s_addr = dst;
 305         icmp = (struct icmphdr *)(buf + sizeof(struct ip));
 306
 307         /* Merge IP header with icmp packet */
 308         assert(stream_get_endp(s) < (sizeof(buf) - sizeof(struct ip)));
 309         stream_get(icmp, s, stream_get_endp(s));
 310
 311         /* icmp->checksum is already calculated */
 312         ip->ip_len = sizeof(struct ip) + stream_get_endp(s);
 313
 314         on = 1;
 315         if (setsockopt(irdp_sock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
 316                        sizeof(on))
 317             < 0)
 318                 zlog_debug("sendto %s", safe_strerror(errno));
 319
 320
 321         if (dst == INADDR_BROADCAST) {
 322                 on = 1;
 323                 if (setsockopt(irdp_sock, SOL_SOCKET, SO_BROADCAST, (char *)&on,
 324                                sizeof(on))
 325                     < 0)
 326                         zlog_debug("sendto %s", safe_strerror(errno));
 327         }
 328
 329         if (dst != INADDR_BROADCAST)
 330                 setsockopt_ipv4_multicast_loop(irdp_sock, 0);
 331
 332         memset(&sockdst, 0, sizeof(sockdst));
 333         sockdst.sin_family = AF_INET;
 334         sockdst.sin_addr.s_addr = dst;
 335
 336         cmsg = (struct cmsghdr *)(msgbuf + sizeof(struct msghdr));
 337         cmsg->cmsg_len = sizeof(struct cmsghdr) + sizeof(struct in_pktinfo);
 338         cmsg->cmsg_level = SOL_IP;
 339         cmsg->cmsg_type = IP_PKTINFO;
 340         pktinfo = (struct in_pktinfo *)CMSG_DATA(cmsg);
 341         pktinfo->ipi_ifindex = ifp->ifindex;
 342         pktinfo->ipi_spec_dst.s_addr = src;
 343         pktinfo->ipi_addr.s_addr = src;
 344
 345         iovector.iov_base = (void *)buf;
 346         iovector.iov_len = ip->ip_len;
 347         msg = (struct msghdr *)msgbuf;
 348         msg->msg_name = &sockdst;
 349         msg->msg_namelen = sizeof(sockdst);
 350         msg->msg_iov = &iovector;
 351         msg->msg_iovlen = 1;
 352         msg->msg_control = cmsg;
 353         msg->msg_controllen = cmsg->cmsg_len;
 354
 355         sockopt_iphdrincl_swab_htosys(ip);
 356
 357         if (sendmsg(irdp_sock, msg, 0) < 0) {
 358                 zlog_debug("sendto %s", safe_strerror(errno));
 359         }
 360         /*   printf("TX on %s idx %d\n", ifp->name, ifp->ifindex); */
 361 }