1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <net/if.h> 30 31 #include <errno.h> 32 #include <ifaddrs.h> 33 #include <linux/if_packet.h> 34 #include <linux/netlink.h> 35 #include <linux/rtnetlink.h> 36 #include <linux/sockios.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <sys/ioctl.h> 40 #include <sys/socket.h> 41 #include <unistd.h> 42 43 #include "private/ErrnoRestorer.h" 44 45 #include "bionic_netlink.h" 46 47 char* if_indextoname(unsigned ifindex, char* ifname) { 48 int s = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0); 49 if (s == -1) return nullptr; 50 51 struct ifreq ifr; 52 memset(&ifr, 0, sizeof(ifr)); 53 ifr.ifr_ifindex = ifindex; 54 55 int rc = ioctl(s, SIOCGIFNAME, &ifr); 56 ErrnoRestorer errno_restorer; 57 close(s); 58 return (rc == -1) ? nullptr : strncpy(ifname, ifr.ifr_name, IFNAMSIZ); 59 } 60 61 unsigned if_nametoindex(const char* ifname) { 62 int s = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0); 63 if (s == -1) return 0; 64 65 struct ifreq ifr; 66 memset(&ifr, 0, sizeof(ifr)); 67 strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 68 ifr.ifr_name[IFNAMSIZ - 1] = 0; 69 70 int rc = ioctl(s, SIOCGIFINDEX, &ifr); 71 ErrnoRestorer errno_restorer; 72 close(s); 73 return (rc == -1) ? 0 : ifr.ifr_ifindex; 74 } 75 76 struct if_list { 77 if_list* next; 78 struct if_nameindex data; 79 80 explicit if_list(if_list** list) { 81 // push_front onto `list`. 82 next = *list; 83 *list = this; 84 } 85 86 static void Free(if_list* list, bool names_too) { 87 while (list) { 88 if_list* it = list; 89 list = it->next; 90 if (names_too) free(it->data.if_name); 91 free(it); 92 } 93 } 94 }; 95 96 static void __if_nameindex_callback(void* context, nlmsghdr* hdr) { 97 if_list** list = reinterpret_cast<if_list**>(context); 98 if (hdr->nlmsg_type == RTM_NEWLINK) { 99 ifinfomsg* ifi = reinterpret_cast<ifinfomsg*>(NLMSG_DATA(hdr)); 100 101 // Create a new entry and set the interface index. 102 if_list* new_link = new if_list(list); 103 new_link->data.if_index = ifi->ifi_index; 104 105 // Go through the various bits of information and find the name. 106 rtattr* rta = IFLA_RTA(ifi); 107 size_t rta_len = IFLA_PAYLOAD(hdr); 108 while (RTA_OK(rta, rta_len)) { 109 if (rta->rta_type == IFLA_IFNAME) { 110 new_link->data.if_name = strndup(reinterpret_cast<char*>(RTA_DATA(rta)), RTA_PAYLOAD(rta)); 111 } 112 rta = RTA_NEXT(rta, rta_len); 113 } 114 } 115 } 116 117 struct if_nameindex* if_nameindex() { 118 if_list* list = nullptr; 119 120 // Open the netlink socket and ask for all the links; 121 NetlinkConnection nc; 122 bool okay = nc.SendRequest(RTM_GETLINK) && nc.ReadResponses(__if_nameindex_callback, &list); 123 if (!okay) { 124 if_list::Free(list, true); 125 return nullptr; 126 } 127 128 // Count the interfaces. 129 size_t interface_count = 0; 130 for (if_list* it = list; it != nullptr; it = it->next) { 131 ++interface_count; 132 } 133 134 // Build the array POSIX requires us to return. 135 struct if_nameindex* result = new struct if_nameindex[interface_count + 1]; 136 if (result) { 137 struct if_nameindex* out = result; 138 for (if_list* it = list; it != nullptr; it = it->next) { 139 out->if_index = it->data.if_index; 140 out->if_name = it->data.if_name; 141 ++out; 142 } 143 out->if_index = 0; 144 out->if_name = nullptr; 145 } 146 147 // Free temporary storage. 148 if_list::Free(list, false); 149 150 return result; 151 } 152 153 void if_freenameindex(struct if_nameindex* array) { 154 if (array == nullptr) return; 155 156 struct if_nameindex* ptr = array; 157 while (ptr->if_index != 0 || ptr->if_name != nullptr) { 158 free(ptr->if_name); 159 ++ptr; 160 } 161 162 delete[] array; 163 } 164
