1 | /* $KAME: if_indextoname.c,v 1.7 2000/11/08 03:09:30 itojun Exp $ */ |
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2 | |
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3 | /*- |
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4 | * Copyright (c) 1997, 2000 |
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5 | * Berkeley Software Design, Inc. All rights reserved. |
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6 | * |
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7 | * Redistribution and use in source and binary forms, with or without |
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8 | * modification, are permitted provided that the following conditions |
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9 | * are met: |
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10 | * 1. Redistributions of source code must retain the above copyright |
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11 | * notice, this list of conditions and the following disclaimer. |
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12 | * |
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13 | * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND |
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14 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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15 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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16 | * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE |
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17 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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18 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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19 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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20 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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21 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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22 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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23 | * SUCH DAMAGE. |
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24 | * |
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25 | * BSDI Id: if_indextoname.c,v 2.3 2000/04/17 22:38:05 dab Exp |
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26 | */ |
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27 | |
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28 | #include <rtems/bsd/sys/cdefs.h> |
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29 | |
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30 | #include <sys/types.h> |
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31 | #include <sys/socket.h> |
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32 | #include <net/if_dl.h> |
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33 | #include <net/if.h> |
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34 | #include <ifaddrs.h> |
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35 | #include <stdlib.h> |
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36 | #include <string.h> |
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37 | #include <errno.h> |
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38 | |
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39 | /* |
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40 | * From RFC 2533: |
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41 | * |
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42 | * The second function maps an interface index into its corresponding |
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43 | * name. |
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44 | * |
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45 | * #include <net/if.h> |
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46 | * |
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47 | * char *if_indextoname(unsigned int ifindex, char *ifname); |
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48 | * |
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49 | * The ifname argument must point to a buffer of at least IF_NAMESIZE |
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50 | * bytes into which the interface name corresponding to the specified |
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51 | * index is returned. (IF_NAMESIZE is also defined in <net/if.h> and |
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52 | * its value includes a terminating null byte at the end of the |
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53 | * interface name.) This pointer is also the return value of the |
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54 | * function. If there is no interface corresponding to the specified |
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55 | * index, NULL is returned, and errno is set to ENXIO, if there was a |
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56 | * system error (such as running out of memory), if_indextoname returns |
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57 | * NULL and errno would be set to the proper value (e.g., ENOMEM). |
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58 | */ |
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59 | |
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60 | char * |
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61 | if_indextoname(unsigned int ifindex, char *ifname) |
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62 | { |
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63 | struct ifaddrs *ifaddrs, *ifa; |
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64 | int error = 0; |
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65 | |
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66 | if (getifaddrs(&ifaddrs) < 0) |
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67 | return(NULL); /* getifaddrs properly set errno */ |
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68 | |
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69 | for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { |
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70 | if (ifa->ifa_addr && |
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71 | ifa->ifa_addr->sa_family == AF_LINK && |
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72 | ifindex == ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index) |
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73 | break; |
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74 | } |
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75 | |
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76 | if (ifa == NULL) { |
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77 | error = ENXIO; |
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78 | ifname = NULL; |
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79 | } |
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80 | else |
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81 | strncpy(ifname, ifa->ifa_name, IFNAMSIZ); |
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82 | |
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83 | freeifaddrs(ifaddrs); |
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84 | |
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85 | errno = error; |
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86 | return(ifname); |
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87 | } |
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