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/interface.h"
  58 #include "zebra/rtadv.h"
  59 #include "zebra/rib.h"
  60 #include "zebra/zebra_router.h"
  61 #include "zebra/redistribute.h"
  62 #include "zebra/irdp.h"
  63 #include "zebra/zebra_errors.h"
  64
  65
  66 /* GLOBAL VARS */
  67
  68 int irdp_sock = -1;
  69
  70 extern struct thread *t_irdp_raw;
  71
  72 static void parse_irdp_packet(char *p, int len, struct interface *ifp)
  73 {
  74         struct ip *ip = (struct ip *)p;
  75         struct icmphdr *icmp;
  76         struct in_addr src;
  77         int ip_hlen, iplen, datalen;
  78         struct zebra_if *zi;
  79         struct irdp_interface *irdp;
  80         uint16_t saved_chksum;
  81         char buf[PREFIX_STRLEN];
  82
  83         zi = ifp->info;
  84         if (!zi)
  85                 return;
  86
  87         irdp = zi->irdp;
  88         if (!irdp)
  89                 return;
  90
  91         ip_hlen = ip->ip_hl << 2;
  92
  93         sockopt_iphdrincl_swab_systoh(ip);
  94
  95         iplen = ip->ip_len;
  96         datalen = len - ip_hlen;
  97         src = ip->ip_src;
  98
  99         if (len != iplen) {
 100                 flog_err(EC_ZEBRA_IRDP_LEN_MISMATCH,
 101                          "IRDP: RX length doesn't match IP length");
 102                 return;
 103         }
 104
 105         if (iplen < ICMP_MINLEN) {
 106                 flog_err(EC_ZEBRA_IRDP_LEN_MISMATCH,
 107                          "IRDP: RX ICMP packet too short from %pI4",
 108                          &src);
 109                 return;
 110         }
 111
 112         /* XXX: RAW doesn't receive link-layer, surely? ??? */
 113         /* Check so we don't checksum packets longer than oure RX_BUF - (ethlen
 114          +
 115          len of IP-header) 14+20 */
 116         if (iplen > IRDP_RX_BUF - 34) {
 117                 flog_err(EC_ZEBRA_IRDP_LEN_MISMATCH,
 118                          "IRDP: RX ICMP packet too long from %pI4",
 119                          &src);
 120                 return;
 121         }
 122
 123         icmp = (struct icmphdr *)(p + ip_hlen);
 124
 125         saved_chksum = icmp->checksum;
 126         icmp->checksum = 0;
 127         /* check icmp checksum */
 128         if (in_cksum(icmp, datalen) != saved_chksum) {
 129                 flog_warn(
 130                         EC_ZEBRA_IRDP_BAD_CHECKSUM,
 131                         "IRDP: RX ICMP packet from %pI4 Bad checksum, silently ignored",
 132                         &src);
 133                 return;
 134         }
 135
 136         /* Handle just only IRDP */
 137         if (!(icmp->type == ICMP_ROUTERADVERT
 138               || icmp->type == ICMP_ROUTERSOLICIT))
 139                 return;
 140
 141         if (icmp->code != 0) {
 142                 flog_warn(
 143                         EC_ZEBRA_IRDP_BAD_TYPE_CODE,
 144                         "IRDP: RX packet type %d from %pI4 Bad ICMP type code, silently ignored",
 145                         icmp->type, &src);
 146                 return;
 147         }
 148
 149         if (!((ntohl(ip->ip_dst.s_addr) == INADDR_BROADCAST)
 150               && (irdp->flags & IF_BROADCAST))
 151             || (ntohl(ip->ip_dst.s_addr) == INADDR_ALLRTRS_GROUP
 152                 && !(irdp->flags & IF_BROADCAST))) {
 153                 flog_warn(
 154                         EC_ZEBRA_IRDP_BAD_RX_FLAGS,
 155                         "IRDP: RX illegal from %pI4 to %s while %s operates in %s; Please correct settings",
 156                         &src,
 157                         ntohl(ip->ip_dst.s_addr) == INADDR_ALLRTRS_GROUP
 158                                 ? "multicast"
 159                                 : inet_ntop(AF_INET, &ip->ip_dst,
 160                                             buf, sizeof(buf)),
 161                         ifp->name,
 162                         irdp->flags & IF_BROADCAST ? "broadcast" : "multicast");
 163                 return;
 164         }
 165
 166         switch (icmp->type) {
 167         case ICMP_ROUTERADVERT:
 168                 break;
 169
 170         case ICMP_ROUTERSOLICIT:
 171
 172                 if (irdp->flags & IF_DEBUG_MESSAGES)
 173                         zlog_debug("IRDP: RX Solicit on %s from %pI4",
 174                                    ifp->name, &src);
 175
 176                 process_solicit(ifp);
 177                 break;
 178
 179         default:
 180                 flog_warn(
 181                         EC_ZEBRA_IRDP_BAD_TYPE_CODE,
 182                         "IRDP: RX packet type %d from %pI4 Bad ICMP type code, silently ignored",
 183                         icmp->type, &src);
 184         }
 185 }
 186
 187 static int irdp_recvmsg(int sock, uint8_t *buf, int size, int *ifindex)
 188 {
 189         struct msghdr msg;
 190         struct iovec iov;
 191         char adata[CMSG_SPACE(SOPT_SIZE_CMSG_PKTINFO_IPV4())];
 192         int ret;
 193
 194         memset(&msg, 0, sizeof(msg));
 195         msg.msg_name = (void *)0;
 196         msg.msg_namelen = 0;
 197         msg.msg_iov = &iov;
 198         msg.msg_iovlen = 1;
 199         msg.msg_control = (void *)adata;
 200         msg.msg_controllen = sizeof(adata);
 201
 202         iov.iov_base = buf;
 203         iov.iov_len = size;
 204
 205         ret = recvmsg(sock, &msg, 0);
 206         if (ret < 0) {
 207                 flog_warn(EC_LIB_SOCKET, "IRDP: recvmsg: read error %s",
 208                           safe_strerror(errno));
 209                 return ret;
 210         }
 211
 212         if (msg.msg_flags & MSG_TRUNC) {
 213                 flog_warn(EC_LIB_SOCKET, "IRDP: recvmsg: truncated message");
 214                 return ret;
 215         }
 216         if (msg.msg_flags & MSG_CTRUNC) {
 217                 flog_warn(EC_LIB_SOCKET,
 218                           "IRDP: recvmsg: truncated control message");
 219                 return ret;
 220         }
 221
 222         *ifindex = getsockopt_ifindex(AF_INET, &msg);
 223
 224         return ret;
 225 }
 226
 227 void irdp_read_raw(struct thread *r)
 228 {
 229         struct interface *ifp;
 230         struct zebra_if *zi;
 231         struct irdp_interface *irdp;
 232         char buf[IRDP_RX_BUF];
 233         int ret, ifindex = 0;
 234
 235         int irdp_sock = THREAD_FD(r);
 236         thread_add_read(zrouter.master, irdp_read_raw, NULL, irdp_sock,
 237                         &t_irdp_raw);
 238
 239         ret = irdp_recvmsg(irdp_sock, (uint8_t *)buf, IRDP_RX_BUF, &ifindex);
 240
 241         if (ret < 0)
 242                 flog_warn(EC_LIB_SOCKET, "IRDP: RX Error length = %d", ret);
 243
 244         ifp = if_lookup_by_index(ifindex, VRF_DEFAULT);
 245         if (!ifp)
 246                 return;
 247
 248         zi = ifp->info;
 249         if (!zi)
 250                 return;
 251
 252         irdp = zi->irdp;
 253         if (!irdp)
 254                 return;
 255
 256         if (!(irdp->flags & IF_ACTIVE)) {
 257
 258                 if (irdp->flags & IF_DEBUG_MISC)
 259                         zlog_debug("IRDP: RX ICMP for disabled interface %s",
 260                                    ifp->name);
 261                 return;
 262         }
 263
 264         if (irdp->flags & IF_DEBUG_PACKET) {
 265                 int i;
 266                 zlog_debug("IRDP: RX (idx %d) ", ifindex);
 267                 for (i = 0; i < ret; i++)
 268                         zlog_debug("IRDP: RX %x ", buf[i] & 0xFF);
 269         }
 270
 271         parse_irdp_packet(buf, ret, ifp);
 272 }
 273
 274 void send_packet(struct interface *ifp, struct stream *s, uint32_t dst,
 275                  struct prefix *p, uint32_t ttl)
 276 {
 277         static struct sockaddr_in sockdst = {AF_INET};
 278         struct ip *ip;
 279         struct icmphdr *icmp;
 280         struct msghdr *msg;
 281         struct cmsghdr *cmsg;
 282         struct iovec iovector;
 283         char msgbuf[256];
 284         char buf[256];
 285         struct in_pktinfo *pktinfo;
 286         unsigned long src;
 287         uint8_t on;
 288
 289         if (!(ifp->flags & IFF_UP))
 290                 return;
 291
 292         if (p)
 293                 src = ntohl(p->u.prefix4.s_addr);
 294         else
 295                 src = 0; /* Is filled in */
 296
 297         ip = (struct ip *)buf;
 298         ip->ip_hl = sizeof(struct ip) >> 2;
 299         ip->ip_v = IPVERSION;
 300         ip->ip_tos = 0xC0;
 301         ip->ip_off = 0L;
 302         ip->ip_p = 1; /* IP_ICMP */
 303         ip->ip_ttl = ttl;
 304         ip->ip_src.s_addr = src;
 305         ip->ip_dst.s_addr = dst;
 306         icmp = (struct icmphdr *)(buf + sizeof(struct ip));
 307
 308         /* Merge IP header with icmp packet */
 309         assert(stream_get_endp(s) < (sizeof(buf) - sizeof(struct ip)));
 310         stream_get(icmp, s, stream_get_endp(s));
 311
 312         /* icmp->checksum is already calculated */
 313         ip->ip_len = sizeof(struct ip) + stream_get_endp(s);
 314
 315         on = 1;
 316         if (setsockopt(irdp_sock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
 317                        sizeof(on))
 318             < 0)
 319                 flog_err(EC_LIB_SOCKET,
 320                          "IRDP: Cannot set IP_HDRINCLU %s(%d) on %s",
 321                          safe_strerror(errno), errno, ifp->name);
 322
 323
 324         if (dst == INADDR_BROADCAST) {
 325                 uint32_t bon = 1;
 326
 327                 if (setsockopt(irdp_sock, SOL_SOCKET, SO_BROADCAST, &bon,
 328                                sizeof(bon))
 329                     < 0)
 330                         flog_err(EC_LIB_SOCKET,
 331                                  "IRDP: Cannot set SO_BROADCAST %s(%d) on %s",
 332                                  safe_strerror(errno), errno, ifp->name);
 333         }
 334
 335         if (dst != INADDR_BROADCAST)
 336                 setsockopt_ipv4_multicast_loop(irdp_sock, 0);
 337
 338         memset(&sockdst, 0, sizeof(sockdst));
 339         sockdst.sin_family = AF_INET;
 340         sockdst.sin_addr.s_addr = dst;
 341
 342         cmsg = (struct cmsghdr *)(msgbuf + sizeof(struct msghdr));
 343         cmsg->cmsg_len = sizeof(struct cmsghdr) + sizeof(struct in_pktinfo);
 344         cmsg->cmsg_level = SOL_IP;
 345         cmsg->cmsg_type = IP_PKTINFO;
 346         pktinfo = (struct in_pktinfo *)CMSG_DATA(cmsg);
 347         pktinfo->ipi_ifindex = ifp->ifindex;
 348         pktinfo->ipi_spec_dst.s_addr = src;
 349         pktinfo->ipi_addr.s_addr = src;
 350
 351         iovector.iov_base = (void *)buf;
 352         iovector.iov_len = ip->ip_len;
 353         msg = (struct msghdr *)msgbuf;
 354         msg->msg_name = &sockdst;
 355         msg->msg_namelen = sizeof(sockdst);
 356         msg->msg_iov = &iovector;
 357         msg->msg_iovlen = 1;
 358         msg->msg_control = cmsg;
 359         msg->msg_controllen = cmsg->cmsg_len;
 360
 361         sockopt_iphdrincl_swab_htosys(ip);
 362
 363         if (sendmsg(irdp_sock, msg, 0) < 0)
 364                 flog_err(EC_LIB_SOCKET,
 365                          "IRDP: sendmsg send failure %s(%d) on %s",
 366                          safe_strerror(errno), errno, ifp->name);
 367 }