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 #include "if.h"
  40 #include "vty.h"
  41 #include "sockunion.h"
  42 #include "prefix.h"
  43 #include "command.h"
  44 #include "memory.h"
  45 #include "zebra_memory.h"
  46 #include "stream.h"
  47 #include "ioctl.h"
  48 #include "connected.h"
  49 #include "log.h"
  50 #include "zclient.h"
  51 #include "thread.h"
  52 #include "zebra/interface.h"
  53 #include "zebra/rtadv.h"
  54 #include "zebra/rib.h"
  55 #include "zebra/zserv.h"
  56 #include "zebra/redistribute.h"
  57 #include "zebra/irdp.h"
  58 #include <netinet/ip_icmp.h>
  59 #include "if.h"
  60 #include "checksum.h"
  61 #include "sockunion.h"
  62 #include "log.h"
  63 #include "sockopt.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
  81         zi = ifp->info;
  82         if (!zi)
  83                 return;
  84
  85         irdp = zi->irdp;
  86         if (!irdp)
  87                 return;
  88
  89         ip_hlen = ip->ip_hl << 2;
  90
  91         sockopt_iphdrincl_swab_systoh(ip);
  92
  93         iplen = ip->ip_len;
  94         datalen = len - ip_hlen;
  95         src = ip->ip_src;
  96
  97         if (len != iplen) {
  98                 zlog_err("IRDP: RX length doesnt match IP length");
  99                 return;
 100         }
 101
 102         if (iplen < ICMP_MINLEN) {
 103                 zlog_err("IRDP: RX ICMP packet too short from %s\n",
 104                          inet_ntoa(src));
 105                 return;
 106         }
 107
 108         /* XXX: RAW doesnt receive link-layer, surely? ??? */
 109         /* Check so we don't checksum packets longer than oure RX_BUF - (ethlen
 110          +
 111          len of IP-header) 14+20 */
 112         if (iplen > IRDP_RX_BUF - 34) {
 113                 zlog_err("IRDP: RX ICMP packet too long from %s\n",
 114                          inet_ntoa(src));
 115                 return;
 116         }
 117
 118         icmp = (struct icmphdr *)(p + ip_hlen);
 119
 120         /* check icmp checksum */
 121         if (in_cksum(icmp, datalen) != icmp->checksum) {
 122                 zlog_warn(
 123                         "IRDP: RX ICMP packet from %s. Bad checksum, silently ignored",
 124                         inet_ntoa(src));
 125                 return;
 126         }
 127
 128         /* Handle just only IRDP */
 129         if (!(icmp->type == ICMP_ROUTERADVERT
 130               || icmp->type == ICMP_ROUTERSOLICIT))
 131                 return;
 132
 133         if (icmp->code != 0) {
 134                 zlog_warn(
 135                         "IRDP: RX packet type %d from %s. Bad ICMP type code,"
 136                         " silently ignored",
 137                         icmp->type, inet_ntoa(src));
 138                 return;
 139         }
 140
 141         if (!((ntohl(ip->ip_dst.s_addr) == INADDR_BROADCAST)
 142               && (irdp->flags & IF_BROADCAST))
 143             || (ntohl(ip->ip_dst.s_addr) == INADDR_ALLRTRS_GROUP
 144                 && !(irdp->flags & IF_BROADCAST))) {
 145                 zlog_warn(
 146                         "IRDP: RX illegal from %s to %s while %s operates in %s\n",
 147                         inet_ntoa(src),
 148                         ntohl(ip->ip_dst.s_addr) == INADDR_ALLRTRS_GROUP
 149                                 ? "multicast"
 150                                 : inet_ntoa(ip->ip_dst),
 151                         ifp->name,
 152                         irdp->flags & IF_BROADCAST ? "broadcast" : "multicast");
 153
 154                 zlog_warn("IRDP: Please correct settings\n");
 155                 return;
 156         }
 157
 158         switch (icmp->type) {
 159         case ICMP_ROUTERADVERT:
 160                 break;
 161
 162         case ICMP_ROUTERSOLICIT:
 163
 164                 if (irdp->flags & IF_DEBUG_MESSAGES)
 165                         zlog_debug("IRDP: RX Solicit on %s from %s\n",
 166                                    ifp->name, inet_ntoa(src));
 167
 168                 process_solicit(ifp);
 169                 break;
 170
 171         default:
 172                 zlog_warn(
 173                         "IRDP: RX type %d from %s. Bad ICMP type, silently ignored",
 174                         icmp->type, inet_ntoa(src));
 175         }
 176 }
 177
 178 static int irdp_recvmsg(int sock, u_char *buf, int size, int *ifindex)
 179 {
 180         struct msghdr msg;
 181         struct iovec iov;
 182         char adata[CMSG_SPACE(SOPT_SIZE_CMSG_PKTINFO_IPV4())];
 183         int ret;
 184
 185         msg.msg_name = (void *)0;
 186         msg.msg_namelen = 0;
 187         msg.msg_iov = &iov;
 188         msg.msg_iovlen = 1;
 189         msg.msg_control = (void *)adata;
 190         msg.msg_controllen = sizeof adata;
 191
 192         iov.iov_base = buf;
 193         iov.iov_len = size;
 194
 195         ret = recvmsg(sock, &msg, 0);
 196         if (ret < 0) {
 197                 zlog_warn("IRDP: recvmsg: read error %s", safe_strerror(errno));
 198                 return ret;
 199         }
 200
 201         if (msg.msg_flags & MSG_TRUNC) {
 202                 zlog_warn("IRDP: recvmsg: truncated message");
 203                 return ret;
 204         }
 205         if (msg.msg_flags & MSG_CTRUNC) {
 206                 zlog_warn("IRDP: recvmsg: truncated control message");
 207                 return ret;
 208         }
 209
 210         *ifindex = getsockopt_ifindex(AF_INET, &msg);
 211
 212         return ret;
 213 }
 214
 215 int irdp_read_raw(struct thread *r)
 216 {
 217         struct interface *ifp;
 218         struct zebra_if *zi;
 219         struct irdp_interface *irdp;
 220         char buf[IRDP_RX_BUF];
 221         int ret, ifindex = 0;
 222
 223         int irdp_sock = THREAD_FD(r);
 224         t_irdp_raw = NULL;
 225         thread_add_read(zebrad.master, irdp_read_raw, NULL, irdp_sock,
 226                         &t_irdp_raw);
 227
 228         ret = irdp_recvmsg(irdp_sock, (u_char *)buf, IRDP_RX_BUF, &ifindex);
 229
 230         if (ret < 0)
 231                 zlog_warn("IRDP: RX Error length = %d", ret);
 232
 233         ifp = if_lookup_by_index(ifindex, VRF_DEFAULT);
 234         if (!ifp)
 235                 return ret;
 236
 237         zi = ifp->info;
 238         if (!zi)
 239                 return ret;
 240
 241         irdp = zi->irdp;
 242         if (!irdp)
 243                 return ret;
 244
 245         if (!(irdp->flags & IF_ACTIVE)) {
 246
 247                 if (irdp->flags & IF_DEBUG_MISC)
 248                         zlog_debug("IRDP: RX ICMP for disabled interface %s\n",
 249                                    ifp->name);
 250                 return 0;
 251         }
 252
 253         if (irdp->flags & IF_DEBUG_PACKET) {
 254                 int i;
 255                 zlog_debug("IRDP: RX (idx %d) ", ifindex);
 256                 for (i = 0; i < ret; i++)
 257                         zlog_debug("IRDP: RX %x ", buf[i] & 0xFF);
 258         }
 259
 260         parse_irdp_packet(buf, ret, ifp);
 261
 262         return ret;
 263 }
 264
 265 void send_packet(struct interface *ifp, struct stream *s, u_int32_t dst,
 266                  struct prefix *p, u_int32_t ttl)
 267 {
 268         static struct sockaddr_in sockdst = {AF_INET};
 269         struct ip *ip;
 270         struct icmphdr *icmp;
 271         struct msghdr *msg;
 272         struct cmsghdr *cmsg;
 273         struct iovec iovector;
 274         char msgbuf[256];
 275         char buf[256];
 276         struct in_pktinfo *pktinfo;
 277         u_long src;
 278         u_char on;
 279
 280         if (!(ifp->flags & IFF_UP))
 281                 return;
 282
 283         if (p)
 284                 src = ntohl(p->u.prefix4.s_addr);
 285         else
 286                 src = 0; /* Is filled in */
 287
 288         ip = (struct ip *)buf;
 289         ip->ip_hl = sizeof(struct ip) >> 2;
 290         ip->ip_v = IPVERSION;
 291         ip->ip_tos = 0xC0;
 292         ip->ip_off = 0L;
 293         ip->ip_p = 1; /* IP_ICMP */
 294         ip->ip_ttl = ttl;
 295         ip->ip_src.s_addr = src;
 296         ip->ip_dst.s_addr = dst;
 297         icmp = (struct icmphdr *)(buf + sizeof(struct ip));
 298
 299         /* Merge IP header with icmp packet */
 300         assert(stream_get_endp(s) < (sizeof(buf) - sizeof(struct ip)));
 301         stream_get(icmp, s, stream_get_endp(s));
 302
 303         /* icmp->checksum is already calculated */
 304         ip->ip_len = sizeof(struct ip) + stream_get_endp(s);
 305
 306         on = 1;
 307         if (setsockopt(irdp_sock, IPPROTO_IP, IP_HDRINCL, (char *)&on,
 308                        sizeof(on))
 309             < 0)
 310                 zlog_warn("sendto %s", safe_strerror(errno));
 311
 312
 313         if (dst == INADDR_BROADCAST) {
 314                 on = 1;
 315                 if (setsockopt(irdp_sock, SOL_SOCKET, SO_BROADCAST, (char *)&on,
 316                                sizeof(on))
 317                     < 0)
 318                         zlog_warn("sendto %s", safe_strerror(errno));
 319         }
 320
 321         if (dst != INADDR_BROADCAST)
 322                 setsockopt_ipv4_multicast_loop(irdp_sock, 0);
 323
 324         memset(&sockdst, 0, sizeof(sockdst));
 325         sockdst.sin_family = AF_INET;
 326         sockdst.sin_addr.s_addr = dst;
 327
 328         cmsg = (struct cmsghdr *)(msgbuf + sizeof(struct msghdr));
 329         cmsg->cmsg_len = sizeof(struct cmsghdr) + sizeof(struct in_pktinfo);
 330         cmsg->cmsg_level = SOL_IP;
 331         cmsg->cmsg_type = IP_PKTINFO;
 332         pktinfo = (struct in_pktinfo *)CMSG_DATA(cmsg);
 333         pktinfo->ipi_ifindex = ifp->ifindex;
 334         pktinfo->ipi_spec_dst.s_addr = src;
 335         pktinfo->ipi_addr.s_addr = src;
 336
 337         iovector.iov_base = (void *)buf;
 338         iovector.iov_len = ip->ip_len;
 339         msg = (struct msghdr *)msgbuf;
 340         msg->msg_name = &sockdst;
 341         msg->msg_namelen = sizeof(sockdst);
 342         msg->msg_iov = &iovector;
 343         msg->msg_iovlen = 1;
 344         msg->msg_control = cmsg;
 345         msg->msg_controllen = cmsg->cmsg_len;
 346
 347         sockopt_iphdrincl_swab_htosys(ip);
 348
 349         if (sendmsg(irdp_sock, msg, 0) < 0) {
 350                 zlog_warn("sendto %s", safe_strerror(errno));
 351         }
 352         /*   printf("TX on %s idx %d\n", ifp->name, ifp->ifindex); */
 353 }