release/src/router/radvd/recv.c

   1 /*
   2  *   $Id: recv.c,v 1.14 2011/02/06 03:41:38 reubenhwk Exp $
   3  *
   4  *   Authors:
   5  *    Pedro Roque               <roque@di.fc.ul.pt>
   6  *    Lars Fenneberg            <lf@elemental.net>
   7  *
   8  *   This software is Copyright 1996,1997 by the above mentioned author(s),
   9  *   All Rights Reserved.
  10  *
  11  *   The license which is distributed with this software in the file COPYRIGHT
  12  *   applies to this software. If your distribution is missing this file, you
  13  *   may request it from <pekkas@netcore.fi>.
  14  *
  15  */
  16
  17 #include "config.h"
  18 #include "includes.h"
  19 #include "radvd.h"
  20
  21 int
  22 recv_rs_ra(unsigned char *msg, struct sockaddr_in6 *addr,
  23                  struct in6_pktinfo **pkt_info, int *hoplimit)
  24 {
  25         struct msghdr mhdr;
  26         struct cmsghdr *cmsg;
  27         struct iovec iov;
  28         static unsigned char *chdr = NULL;
  29         static unsigned int chdrlen = 0;
  30         int len;
  31         fd_set rfds;
  32
  33         if( ! chdr )
  34         {
  35                 chdrlen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
  36                                 CMSG_SPACE(sizeof(int));
  37                 if ((chdr = malloc(chdrlen)) == NULL) {
  38                         flog(LOG_ERR, "recv_rs_ra: malloc: %s", strerror(errno));
  39                         return -1;
  40                 }
  41         }
  42
  43         FD_ZERO( &rfds );
  44         FD_SET( sock, &rfds );
  45
  46         if( select( sock+1, &rfds, NULL, NULL, NULL ) < 0 )
  47         {
  48                 if (errno != EINTR)
  49                         flog(LOG_ERR, "select: %s", strerror(errno));
  50
  51                 return -1;
  52         }
  53
  54         iov.iov_len = MSG_SIZE_RECV;
  55         iov.iov_base = (caddr_t) msg;
  56
  57         memset(&mhdr, 0, sizeof(mhdr));
  58         mhdr.msg_name = (caddr_t)addr;
  59         mhdr.msg_namelen = sizeof(*addr);
  60         mhdr.msg_iov = &iov;
  61         mhdr.msg_iovlen = 1;
  62         mhdr.msg_control = (void *)chdr;
  63         mhdr.msg_controllen = chdrlen;
  64
  65         len = recvmsg(sock, &mhdr, 0);
  66
  67         if (len < 0)
  68         {
  69                 if (errno != EINTR)
  70                         flog(LOG_ERR, "recvmsg: %s", strerror(errno));
  71
  72                 return len;
  73         }
  74
  75         *hoplimit = 255;
  76
  77         for (cmsg = CMSG_FIRSTHDR(&mhdr); cmsg != NULL; cmsg = CMSG_NXTHDR(&mhdr, cmsg))
  78         {
  79           if (cmsg->cmsg_level != IPPROTO_IPV6)
  80                 continue;
  81
  82           switch(cmsg->cmsg_type)
  83           {
  84 #ifdef IPV6_HOPLIMIT
  85               case IPV6_HOPLIMIT:
  86                 if ((cmsg->cmsg_len == CMSG_LEN(sizeof(int))) &&
  87                     (*(int *)CMSG_DATA(cmsg) >= 0) &&
  88                     (*(int *)CMSG_DATA(cmsg) < 256))
  89                 {
  90                   *hoplimit = *(int *)CMSG_DATA(cmsg);
  91                 }
  92                 else
  93                 {
  94                   flog(LOG_ERR, "received a bogus IPV6_HOPLIMIT from the kernel! len=%d, data=%d",
  95                         cmsg->cmsg_len, *(int *)CMSG_DATA(cmsg));
  96                   return (-1);
  97                 }
  98                 break;
  99 #endif /* IPV6_HOPLIMIT */
 100               case IPV6_PKTINFO:
 101                 if ((cmsg->cmsg_len == CMSG_LEN(sizeof(struct in6_pktinfo))) &&
 102                     ((struct in6_pktinfo *)CMSG_DATA(cmsg))->ipi6_ifindex)
 103                 {
 104                   *pkt_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
 105                 }
 106                 else
 107                 {
 108                   flog(LOG_ERR, "received a bogus IPV6_PKTINFO from the kernel! len=%d, index=%d",
 109                         cmsg->cmsg_len, ((struct in6_pktinfo *)CMSG_DATA(cmsg))->ipi6_ifindex);
 110                   return (-1);
 111                 }
 112                 break;
 113           }
 114         }
 115
 116         dlog(LOG_DEBUG, 4, "recvmsg len=%d", len);
 117
 118         return len;
 119 }