release/src/router/miniupnpd/bsd/getroute.c

   1 /* $Id: getroute.c,v 1.3 2013/02/06 13:11:45 nanard Exp $ */
   2 /* MiniUPnP project
   3  * http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
   4  * (c) 2006-2013 Thomas Bernard
   5  * This software is subject to the conditions detailed
   6  * in the LICENCE file provided within the distribution */
   7
   8 #include <stdio.h>
   9 #include <syslog.h>
  10 #include <unistd.h>
  11 #include <string.h>
  12 #include <sys/socket.h>
  13 #include <net/if.h>
  14 #include <net/route.h>
  15 #include <netinet/in.h>
  16 #ifdef AF_LINK
  17 #include <net/if_dl.h>
  18 #endif
  19
  20 #include "../config.h"
  21 #include "../upnputils.h"
  22
  23
  24 int
  25 get_src_for_route_to(const struct sockaddr * dst,
  26                      void * src, size_t * src_len,
  27                      int * index)
  28 {
  29         int found = 0;
  30         int s;
  31         int l, i;
  32         char * p;
  33         struct sockaddr * sa;
  34         struct {
  35           struct rt_msghdr m_rtm;
  36           char       m_space[512];
  37         } m_rtmsg;
  38 #define rtm m_rtmsg.m_rtm
  39
  40         if(dst == NULL)
  41                 return -1;
  42 #ifdef __APPLE__
  43         if(dst->sa_family == AF_INET6) {
  44                 syslog(LOG_ERR, "Sorry, get_src_for_route_to() is known to fail with IPV6 on OS X...");
  45                 return -1;
  46         }
  47 #endif
  48         s = socket(PF_ROUTE, SOCK_RAW, dst->sa_family);
  49         if(s < 0) {
  50                 syslog(LOG_ERR, "socket(PF_ROUTE) failed : %m");
  51                 return -1;
  52         }
  53         memset(&rtm, 0, sizeof(rtm));
  54         rtm.rtm_type = RTM_GET;
  55         rtm.rtm_flags = RTF_UP;
  56         rtm.rtm_version = RTM_VERSION;
  57         rtm.rtm_seq = 1;
  58         rtm.rtm_addrs = RTA_DST;        /* destination address */
  59         memcpy(m_rtmsg.m_space, dst, sizeof(struct sockaddr));
  60         rtm.rtm_msglen = sizeof(struct rt_msghdr) + sizeof(struct sockaddr);
  61         if(write(s, &m_rtmsg, rtm.rtm_msglen) < 0) {
  62                 syslog(LOG_ERR, "write: %m");
  63                 close(s);
  64                 return -1;
  65         }
  66
  67         do {
  68                 l = read(s, &m_rtmsg, sizeof(m_rtmsg));
  69                 if(l<0) {
  70                         syslog(LOG_ERR, "read: %m");
  71                         close(s);
  72                         return -1;
  73                 }
  74                 syslog(LOG_DEBUG, "read l=%d seq=%d pid=%d",
  75                        l, rtm.rtm_seq, rtm.rtm_pid);
  76         } while(l > 0 && (rtm.rtm_pid != getpid() || rtm.rtm_seq != 1));
  77         close(s);
  78         p = m_rtmsg.m_space;
  79         if(rtm.rtm_addrs) {
  80                 for(i=1; i<0x8000; i <<= 1) {
  81                         if(i & rtm.rtm_addrs) {
  82                                 char tmp[256] = { 0 };
  83                                 sa = (struct sockaddr *)p;
  84                                 sockaddr_to_string(sa, tmp, sizeof(tmp));
  85                                 syslog(LOG_DEBUG, "type=%d sa_len=%d sa_family=%d %s",
  86                                        i, sa->sa_len, sa->sa_family, tmp);
  87                                 if((i == RTA_DST || i == RTA_GATEWAY) &&
  88                                    (src_len && src)) {
  89                                         size_t len = 0;
  90                                         void * paddr = NULL;
  91                                         if(sa->sa_family == AF_INET) {
  92                                                 paddr = &((struct sockaddr_in *)sa)->sin_addr;
  93                                                 len = sizeof(struct in_addr);
  94                                         } else if(sa->sa_family == AF_INET6) {
  95                                                 paddr = &((struct sockaddr_in6 *)sa)->sin6_addr;
  96                                                 len = sizeof(struct in6_addr);
  97                                         }
  98                                         if(paddr) {
  99                                                 if(*src_len < len) {
 100                                                         syslog(LOG_WARNING, "cannot copy src. %u<%u",
 101                                                                (unsigned)*src_len, (unsigned)len);
 102                                                         return -1;
 103                                                 }
 104                                                 memcpy(src, paddr, len);
 105                                                 *src_len = len;
 106                                                 found = 1;
 107                                         }
 108                                 }
 109 #ifdef AF_LINK
 110                                 if(sa->sa_family == AF_LINK) {
 111                                         struct sockaddr_dl * sdl = (struct sockaddr_dl *)sa;
 112                                         if(index)
 113                                                 *index = sdl->sdl_index;
 114                                 }
 115 #endif
 116                                 p += sa->sa_len;
 117                         }
 118                 }
 119         }
 120         return found ? 0 : -1;
 121 }
 122