socket.c

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/*
 * socket.c -- DHCP server client/server socket creation
 *
 * udhcp client/server
 * Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
 *                      Chris Trew <ctrew@moreton.com.au>
 *
 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <errno.h>
#include <features.h>
#if __GLIBC__ >=2 && __GLIBC_MINOR >= 1
#include <netpacket/packet.h>
#include <net/ethernet.h>
#else
#include <asm/types.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#endif

#include "debug.h"

int read_interface(char *interface, int *ifindex, u_int32_t *addr, unsigned char *arp)
{
        int fd;
        struct ifreq ifr;
        struct sockaddr_in *our_ip;

        memset(&ifr, 0, sizeof(struct ifreq));
        if((fd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) >= 0) {
                ifr.ifr_addr.sa_family = AF_INET;
                strcpy(ifr.ifr_name, interface);

                if (addr) { 
                        if (ioctl(fd, SIOCGIFADDR, &ifr) == 0) {
                                our_ip = (struct sockaddr_in *) &ifr.ifr_addr;
                                *addr = our_ip->sin_addr.s_addr;
                                DEBUG(LOG_INFO, "%s (our ip) = %s", ifr.ifr_name, inet_ntoa(our_ip->sin_addr));
                        } else {
                                LOG(LOG_ERR, "SIOCGIFADDR failed, is the interface up and configured?: %s", 
                                                strerror(errno));
                                return -1;
                        }
                }
                
                if (ioctl(fd, SIOCGIFINDEX, &ifr) == 0) {
                        DEBUG(LOG_INFO, "adapter index %d", ifr.ifr_ifindex);
                        *ifindex = ifr.ifr_ifindex;
                } else {
                        LOG(LOG_ERR, "SIOCGIFINDEX failed!: %s", strerror(errno));
                        return -1;
                }
                if (ioctl(fd, SIOCGIFHWADDR, &ifr) == 0) {
                        memcpy(arp, ifr.ifr_hwaddr.sa_data, 6);
                        DEBUG(LOG_INFO, "adapter hardware address %02x:%02x:%02x:%02x:%02x:%02x",
                                arp[0], arp[1], arp[2], arp[3], arp[4], arp[5]);
                } else {
                        LOG(LOG_ERR, "SIOCGIFHWADDR failed!: %s", strerror(errno));
                        return -1;
                }
        } else {
                LOG(LOG_ERR, "socket failed!: %s", strerror(errno));
                return -1;
        }
        close(fd);
        return 0;
}


int listen_socket(unsigned int ip, int port, char *inf)
{
        struct ifreq interface;
        int fd;
        struct sockaddr_in addr;
        int n = 1;

        DEBUG(LOG_INFO, "Opening listen socket on 0x%08x:%d %s\n", ip, port, inf);
        if ((fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
                DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno));
                return -1;
        }
        
        memset(&addr, 0, sizeof(addr));
        addr.sin_family = AF_INET;
        addr.sin_port = htons(port);
        addr.sin_addr.s_addr = ip;

        if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) == -1) {
                close(fd);
                return -1;
        }
        if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST, (char *) &n, sizeof(n)) == -1) {
                close(fd);
                return -1;
        }

        strncpy(interface.ifr_ifrn.ifrn_name, inf, IFNAMSIZ);
        if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,(char *)&interface, sizeof(interface)) < 0) {
                close(fd);
                return -1;
        }

        if (bind(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr)) == -1) {
                close(fd);
                return -1;
        }
        
        return fd;
}


int raw_socket(int ifindex)
{
        int fd;
        struct sockaddr_ll sock;

        DEBUG(LOG_INFO, "Opening raw socket on ifindex %d\n", ifindex);
        if ((fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
                DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno));
                return -1;
        }
        
        sock.sll_family = AF_PACKET;
        sock.sll_protocol = htons(ETH_P_IP);
        sock.sll_ifindex = ifindex;
        if (bind(fd, (struct sockaddr *) &sock, sizeof(sock)) < 0) {
                DEBUG(LOG_ERR, "bind call failed: %s", strerror(errno));
                close(fd);
                return -1;
        }

        return fd;
}

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