LXR 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 "common.h"
  26#include <net/if.h>
  27
  28int FAST_FUNC udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac)
  29{
  30        /* char buffer instead of bona-fide struct avoids aliasing warning */
  31        char ifr_buf[sizeof(struct ifreq)];
  32        struct ifreq *const ifr = (void *)ifr_buf;
  33
  34        int fd;
  35        struct sockaddr_in *our_ip;
  36
  37        memset(ifr, 0, sizeof(*ifr));
  38        fd = xsocket(AF_INET, SOCK_RAW, IPPROTO_RAW);
  39
  40        ifr->ifr_addr.sa_family = AF_INET;
  41        strncpy_IFNAMSIZ(ifr->ifr_name, interface);
  42        if (nip) {
  43                if (ioctl_or_perror(fd, SIOCGIFADDR, ifr,
  44                        "is interface %s up and configured?", interface)
  45                ) {
  46                        close(fd);
  47                        return -1;
  48                }
  49                our_ip = (struct sockaddr_in *) &ifr->ifr_addr;
  50                *nip = our_ip->sin_addr.s_addr;
  51                log1("IP %s", inet_ntoa(our_ip->sin_addr));
  52        }
  53
  54        if (ifindex) {
  55                if (ioctl_or_warn(fd, SIOCGIFINDEX, ifr) != 0) {
  56                        close(fd);
  57                        return -1;
  58                }
  59                log2("ifindex %d", ifr->ifr_ifindex);
  60                *ifindex = ifr->ifr_ifindex;
  61        }
  62
  63        if (mac) {
  64                if (ioctl_or_warn(fd, SIOCGIFHWADDR, ifr) != 0) {
  65                        close(fd);
  66                        return -1;
  67                }
  68                memcpy(mac, ifr->ifr_hwaddr.sa_data, 6);
  69                log2("MAC %02x:%02x:%02x:%02x:%02x:%02x",
  70                        mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
  71        }
  72
  73        close(fd);
  74        return 0;
  75}
  76
  77/* 1. None of the callers expects it to ever fail */
  78/* 2. ip was always INADDR_ANY */
  79int FAST_FUNC udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf)
  80{
  81        int fd;
  82        struct sockaddr_in addr;
  83        char *colon;
  84
  85        log1("opening listen socket on *:%d %s", port, inf);
  86        fd = xsocket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
  87
  88        setsockopt_reuseaddr(fd);
  89        if (setsockopt_broadcast(fd) == -1)
  90                bb_perror_msg_and_die("SO_BROADCAST");
  91
  92        /* SO_BINDTODEVICE doesn't work on ethernet aliases (ethN:M) */
  93        colon = strrchr(inf, ':');
  94        if (colon)
  95                *colon = '\0';
  96
  97        if (setsockopt_bindtodevice(fd, inf))
  98                xfunc_die(); /* warning is already printed */
  99
 100        if (colon)
 101                *colon = ':';
 102
 103        memset(&addr, 0, sizeof(addr));
 104        addr.sin_family = AF_INET;
 105        addr.sin_port = htons(port);
 106        /* addr.sin_addr.s_addr = ip; - all-zeros is INADDR_ANY */
 107        xbind(fd, (struct sockaddr *)&addr, sizeof(addr));
 108
 109        return fd;
 110}
 111