release/src/router/busybox/networking/udhcp/socket.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * DHCP server client/server socket creation
   4  *
   5  * udhcp client/server
   6  * Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
   7  *                      Chris Trew <ctrew@moreton.com.au>
   8  *
   9  * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24  */
  25 #include <net/if.h>
  26 #if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined _NEWLIB_VERSION
  27 # include <netpacket/packet.h>
  28 # include <net/ethernet.h>
  29 #else
  30 # include <asm/types.h>
  31 # include <linux/if_packet.h>
  32 # include <linux/if_ether.h>
  33 #endif
  34
  35 #include "common.h"
  36
  37 int FAST_FUNC udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac, uint16_t *mtu)
  38 {
  39
  40         /* char buffer instead of bona-fide struct avoids aliasing warning */
  41         char ifr_buf[sizeof(struct ifreq)];
  42         struct ifreq *const ifr = (void *)ifr_buf;
  43
  44         int fd;
  45         struct sockaddr_in *our_ip;
  46
  47         memset(ifr, 0, sizeof(*ifr));
  48         fd = xsocket(AF_INET, SOCK_RAW, IPPROTO_RAW);
  49
  50         ifr->ifr_addr.sa_family = AF_INET;
  51         strncpy_IFNAMSIZ(ifr->ifr_name, interface);
  52         if (nip) {
  53                 if (ioctl_or_perror(fd, SIOCGIFADDR, ifr,
  54                         "is interface %s up and configured?", interface)
  55                 ) {
  56                         close(fd);
  57                         return -1;
  58                 }
  59                 our_ip = (struct sockaddr_in *) &ifr->ifr_addr;
  60                 *nip = our_ip->sin_addr.s_addr;
  61                 log1("IP %s", inet_ntoa(our_ip->sin_addr));
  62         }
  63
  64         if (ifindex) {
  65                 if (ioctl_or_warn(fd, SIOCGIFINDEX, ifr) != 0) {
  66                         close(fd);
  67                         return -1;
  68                 }
  69                 log1("Adapter index %d", ifr->ifr_ifindex);
  70                 *ifindex = ifr->ifr_ifindex;
  71         }
  72
  73         if (mac) {
  74                 if (ioctl_or_warn(fd, SIOCGIFHWADDR, ifr) != 0) {
  75                         close(fd);
  76                         return -1;
  77                 }
  78                 memcpy(mac, ifr->ifr_hwaddr.sa_data, 6);
  79                 log1("MAC %02x:%02x:%02x:%02x:%02x:%02x",
  80                         mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
  81         }
  82
  83         if (mtu) {
  84                 if (ioctl_or_warn(fd, SIOCGIFMTU, ifr) != 0) {
  85                         close(fd);
  86                         return -1;
  87                 }
  88                 log1("Adapter mtu %d", ifr->ifr_mtu);
  89                 *mtu = ifr->ifr_mtu;
  90         }
  91
  92         close(fd);
  93         return 0;
  94 }
  95
  96 /* 1. None of the callers expects it to ever fail */
  97 /* 2. ip was always INADDR_ANY */
  98 int FAST_FUNC udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf)
  99 {
 100         int fd;
 101         struct sockaddr_in addr;
 102         char *colon;
 103
 104         log1("Opening listen socket on *:%d %s", port, inf);
 105         fd = xsocket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
 106
 107         setsockopt_reuseaddr(fd);
 108         if (setsockopt_broadcast(fd) == -1)
 109                 bb_perror_msg_and_die("SO_BROADCAST");
 110
 111         /* SO_BINDTODEVICE doesn't work on ethernet aliases (ethN:M) */
 112         colon = strrchr(inf, ':');
 113         if (colon)
 114                 *colon = '\0';
 115
 116         if (setsockopt_bindtodevice(fd, inf))
 117                 xfunc_die(); /* warning is already printed */
 118
 119         if (colon)
 120                 *colon = ':';
 121
 122         memset(&addr, 0, sizeof(addr));
 123         addr.sin_family = AF_INET;
 124         addr.sin_port = htons(port);
 125         /* addr.sin_addr.s_addr = ip; - all-zeros is INADDR_ANY */
 126         xbind(fd, (struct sockaddr *)&addr, sizeof(addr));
 127
 128         return fd;
 129 }