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 Låås at Swedish University of Agricultural Sciences
  32  * for reviewing and tests.
  33  */
  34
  35
  36 #include <zebra.h>
  37
  38
  39 #ifdef HAVE_IRDP
  40
  41 #include "if.h"
  42 #include "vty.h"
  43 #include "sockunion.h"
  44 #include "prefix.h"
  45 #include "command.h"
  46 #include "memory.h"
  47 #include "zebra_memory.h"
  48 #include "stream.h"
  49 #include "ioctl.h"
  50 #include "connected.h"
  51 #include "log.h"
  52 #include "zclient.h"
  53 #include "thread.h"
  54 #include "zebra/interface.h"
  55 #include "zebra/rtadv.h"
  56 #include "zebra/rib.h"
  57 #include "zebra/zserv.h"
  58 #include "zebra/redistribute.h"
  59 #include "zebra/irdp.h"
  60 #include <netinet/ip_icmp.h>
  61 #include "if.h"
  62 #include "checksum.h"
  63 #include "sockunion.h"
  64 #include "log.h"
  65 #include "sockopt.h"
  66
  67
  68 /* GLOBAL VARS */
  69
  70 int irdp_sock = -1;
  71
  72 extern struct thread *t_irdp_raw;
  73
  74 static void parse_irdp_packet(char *p, int len, struct interface *ifp)
  75 {
  76         struct ip *ip = (struct ip *)p;
  77         struct icmphdr *icmp;
  78         struct in_addr src;
  79         int ip_hlen, iplen, datalen;
  80         struct zebra_if *zi;
  81         struct irdp_interface *irdp;
  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                 zlog_err("IRDP: RX length doesnt match IP length");
 101                 return;
 102         }
 103
 104         if (iplen < ICMP_MINLEN) {
 105                 zlog_err("IRDP: RX ICMP packet too short from %s\n",
 106                          inet_ntoa(src));
 107                 return;
 108         }
 109
 110         /* XXX: RAW doesnt receive link-layer, surely? ??? */
 111         /* Check so we don't checksum packets longer than oure RX_BUF - (ethlen
 112          +
 113          len of IP-header) 14+20 */
 114         if (iplen > IRDP_RX_BUF - 34) {
 115                 zlog_err("IRDP: RX ICMP packet too long from %s\n",
 116                          inet_ntoa(src));
 117                 return;
 118         }
 119
 120         icmp = (struct icmphdr *)(p + ip_hlen);
 121
 122         /* check icmp checksum */
 123         if (in_cksum(icmp, datalen) != icmp->checksum) {
 124                 zlog_warn(
 125                         "IRDP: RX ICMP packet from %s. Bad checksum, silently ignored",
 126                         inet_ntoa(src));
 127                 return;
 128         }
 129
 130         /* Handle just only IRDP */
 131         if (!(icmp->type == ICMP_ROUTERADVERT
 132               || icmp->type == ICMP_ROUTERSOLICIT))
 133                 return;
 134
 135         if (icmp->code != 0) {
 136                 zlog_warn(
 137                         "IRDP: RX packet type %d from %s. Bad ICMP type code,"
 138                         " silently ignored",
 139                         icmp->type, inet_ntoa(src));
 140                 return;
 141         }
 142
 143         if (!((ntohl(ip->ip_dst.s_addr) == INADDR_BROADCAST)
 144               && (irdp->flags & IF_BROADCAST))
 145             || (ntohl(ip->ip_dst.s_addr) == INADDR_ALLRTRS_GROUP
 146                 && !(irdp->flags & IF_BROADCAST))) {
 147                 zlog_warn(
 148                         "IRDP: RX illegal from %s to %s while %s operates in %s\n",
 149                         inet_ntoa(src),
 150                         ntohl(ip->ip_dst.s_addr) == INADDR_ALLRTRS_GROUP
 151                                 ? "multicast"
 152                                 : inet_ntoa(ip->ip_dst),
 153                         ifp->name,
 154                         irdp->flags & IF_BROADCAST ? "broadcast" : "multicast");
 155
 156                 zlog_warn("IRDP: Please correct settings\n");
 157                 return;
 158         }
 159
 160         switch (icmp->type) {
 161         case ICMP_ROUTERADVERT:
 162                 break;
 163
 164         case ICMP_ROUTERSOLICIT:
 165
 166                 if (irdp->flags & IF_DEBUG_MESSAGES)
 167                         zlog_debug("IRDP: RX Solicit on %s from %s\n",
 168                                    ifp->name, inet_ntoa(src));
 169
 170                 process_solicit(ifp);
 171                 break;
 172
 173         default:
 174                 zlog_warn(
 175                         "IRDP: RX type %d from %s. Bad ICMP type, silently ignored",
 176                         icmp->type, inet_ntoa(src));
 177         }
 178 }
 179
 180 static int irdp_recvmsg(int sock, u_char *buf, int size, int *ifindex)
 181 {
 182         struct msghdr msg;
 183         struct iovec iov;
 184         char adata[CMSG_SPACE(SOPT_SIZE_CMSG_PKTINFO_IPV4())];
 185         int ret;
 186
 187         msg.msg_name = (void *)0;
 188         msg.msg_namelen = 0;
 189         msg.msg_iov = &iov;
 190         msg.msg_iovlen = 1;
 191         msg.msg_control = (void *)adata;
 192         msg.msg_controllen = sizeof adata;
 193
 194         iov.iov_base = buf;
 195         iov.iov_len = size;
 196
 197         ret = recvmsg(sock, &msg, 0);
 198         if (ret < 0) {
 199                 zlog_warn("IRDP: recvmsg: read error %s", safe_strerror(errno));
 200                 return ret;
 201         }
 202
 203         if (msg.msg_flags & MSG_TRUNC) {
 204                 zlog_warn("IRDP: recvmsg: truncated message");
 205                 return ret;
 206         }
 207         if (msg.msg_flags & MSG_CTRUNC) {
 208                 zlog_warn("IRDP: recvmsg: truncated control message");
 209                 return ret;
 210         }
 211
 212         *ifindex = getsockopt_ifindex(AF_INET, &msg);
 213
 214         return ret;
 215 }
 216
 217 int irdp_read_raw(struct thread *r)
 218 {
 219         struct interface *ifp;
 220         struct zebra_if *zi;
 221         struct irdp_interface *irdp;
 222         char buf[IRDP_RX_BUF];
 223         int ret, ifindex = 0;
 224
 225         int irdp_sock = THREAD_FD(r);
 226         t_irdp_raw = NULL;
 227         thread_add_read(zebrad.master, irdp_read_raw, NULL, irdp_sock,
 228                         &t_irdp_raw);
 229
 230         ret = irdp_recvmsg(irdp_sock, (u_char *)buf, IRDP_RX_BUF, &ifindex);
 231
 232         if (ret < 0)
 233                 zlog_warn("IRDP: RX Error length = %d", ret);
 234
 235         ifp = if_lookup_by_index(ifindex, VRF_DEFAULT);
 236         if (!ifp)
 237                 return ret;
 238
 239         zi = ifp->info;
 240         if (!zi)
 241                 return ret;
 242
 243         irdp = zi->irdp;
 244         if (!irdp)
 245                 return ret;
 246
 247         if (!(irdp->flags & IF_ACTIVE)) {
 248
 249                 if (irdp->flags & IF_DEBUG_MISC)
 250                         zlog_debug("IRDP: RX ICMP for disabled interface %s\n",
 251                                    ifp->name);
 252                 return 0;
 253         }
 254
 255         if (irdp->flags & IF_DEBUG_PACKET) {
 256                 int i;
 257                 zlog_debug("IRDP: RX (idx %d) ", ifindex);
 258                 for (i = 0; i < ret; i++)
 259                         zlog_debug("IRDP: RX %x ", buf[i] & 0xFF);
 260         }
 261
 262         parse_irdp_packet(buf, ret, ifp);
 263
 264         return ret;
 265 }
 266
 267 void send_packet(struct interface *ifp, struct stream *s, u_int32_t dst,
 268                  struct prefix *p, u_int32_t ttl)
 269 {
 270         static struct sockaddr_in sockdst = {AF_INET};
 271         struct ip *ip;
 272         struct icmphdr *icmp;
 273         struct msghdr *msg;
 274         struct cmsghdr *cmsg;
 275         struct iovec iovector;
 276         char msgbuf[256];
 277         char buf[256];
 278         struct in_pktinfo *pktinfo;
 279         u_long src;
 280         u_char on;
 281
 282         if (!(ifp->flags & IFF_UP))
 283                 return;
 284
 285         if (p)
 286                 src = ntohl(p->u.prefix4.s_addr);
 287         else
 288                 src = 0; /* Is filled in */
 289
 290         ip = (struct ip *)buf;
 291         ip->ip_hl = sizeof(struct ip) >> 2;
 292         ip->ip_v = IPVERSION;
 293         ip->ip_tos = 0xC0;
 294         ip->ip_off = 0L;
 295         ip->ip_p = 1; /* IP_ICMP */
 296         ip->ip_ttl = ttl;
 297         ip->ip_src.s_addr = src;
 298         ip->ip_dst.s_addr = dst;
 299         icmp = (struct icmphdr *)(buf + sizeof(struct ip));
 300
 301         /* Merge IP header with icmp packet */
 302         assert(stream_get_endp(s) < (sizeof(buf) - sizeof(struct ip)));
 303         stream_get(icmp, s, stream_get_endp(s));
 304
 305         /* icmp->checksum is already calculated */
 306         ip->ip_len = sizeof(struct ip) + stream_get_endp(s);
 307
 308         on = 1;
 309         if (setsockopt(irdp_sock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
 310                        sizeof(on))
 311             < 0)
 312                 zlog_warn("sendto %s", safe_strerror(errno));
 313
 314
 315         if (dst == INADDR_BROADCAST) {
 316                 on = 1;
 317                 if (setsockopt(irdp_sock, SOL_SOCKET, SO_BROADCAST, (char *)&on,
 318                                sizeof(on))
 319                     < 0)
 320                         zlog_warn("sendto %s", safe_strerror(errno));
 321         }
 322
 323         if (dst != INADDR_BROADCAST)
 324                 setsockopt_ipv4_multicast_loop(irdp_sock, 0);
 325
 326         memset(&sockdst, 0, sizeof(sockdst));
 327         sockdst.sin_family = AF_INET;
 328         sockdst.sin_addr.s_addr = dst;
 329
 330         cmsg = (struct cmsghdr *)(msgbuf + sizeof(struct msghdr));
 331         cmsg->cmsg_len = sizeof(struct cmsghdr) + sizeof(struct in_pktinfo);
 332         cmsg->cmsg_level = SOL_IP;
 333         cmsg->cmsg_type = IP_PKTINFO;
 334         pktinfo = (struct in_pktinfo *)CMSG_DATA(cmsg);
 335         pktinfo->ipi_ifindex = ifp->ifindex;
 336         pktinfo->ipi_spec_dst.s_addr = src;
 337         pktinfo->ipi_addr.s_addr = src;
 338
 339         iovector.iov_base = (void *)buf;
 340         iovector.iov_len = ip->ip_len;
 341         msg = (struct msghdr *)msgbuf;
 342         msg->msg_name = &sockdst;
 343         msg->msg_namelen = sizeof(sockdst);
 344         msg->msg_iov = &iovector;
 345         msg->msg_iovlen = 1;
 346         msg->msg_control = cmsg;
 347         msg->msg_controllen = cmsg->cmsg_len;
 348
 349         sockopt_iphdrincl_swab_htosys(ip);
 350
 351         if (sendmsg(irdp_sock, msg, 0) < 0) {
 352                 zlog_warn("sendto %s", safe_strerror(errno));
 353         }
 354         /*   printf("TX on %s idx %d\n", ifp->name, ifp->ifindex); */
 355 }
 356
 357
 358 #endif /* HAVE_IRDP */