apps/streamer/net_udp.c

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/*
 * Network initialisation
 *
 * (C)2004 Alexander Melichenko <alexlp@freemail.ru>
 *
 * This file consist a portion of code from the UCL Common Code Library (2.4.18)
 * Copyright (c) 1998-2001 University College London
 *
 *  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 3 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, see <http://www.gnu.org/licenses/>.
 */


#include <stdio.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/param.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <net/if.h>
#include <netdb.h>
#include <arpa/inet.h>
//#include <linux/if_packet.h>
#include <linux/if_ether.h>

#include "str.h"
#include "net_udp.h"
#include "arping.h"


int32_t get_src_addr(struct param *p){
    struct ifreq ifr;
    struct sockaddr_in *sin;
    int fd;
    int reuse = 1;
    
    fd = socket(AF_INET, SOCK_DGRAM, 0);
    if (fd < 0) {
        fprintf(stderr, "Socket error\n");
        return -1;
    }

    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &reuse, sizeof(reuse)) != 0) {
        fprintf(stderr, "setsockopt error: SO_REUSEADDR\n");
        return -1;
    }
#ifdef SO_REUSEPORT
    if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, (char *) &reuse,  sizeof(reuse)) != 0) {
        fprintf(stderr, "setsockopt error: SO_REUSEPORT\n");
        return -1;
    }
#endif

    memset(&ifr, 0, sizeof(ifr));
    strcpy(ifr.ifr_name, "eth0");
    
    if(ioctl(fd, SIOCGIFADDR, &ifr) != 0){
        fprintf(stderr, "Local address resolution error\n");
        return -1;
    }

    sin = (struct sockaddr_in*) (ifr.ifr_addr.sa_data+2);
    p->src_addr4 = *(struct in_addr*)sin; 
    p->src       = inet_ntoa(p->src_addr4);

    close(fd);
    
    return 0;
}


int32_t udp_init4(struct param *p)
{
    int reuse = 1;
    struct ifreq ifr;
    struct sockaddr_in *sin;
    in_addr_t src_net, dst_net;

//fprintf(stderr, "udp_init4\n");
    
        if(inet_pton(AF_INET, p->dst, &p->dst_addr4) != 1) {
                struct hostent *h = gethostbyname(p->dst);
                if(h == NULL) {
                        fprintf(stderr, "Can't resolve IP address for %s\n", p->dst);
                        return -1;
                }
                memcpy(&(p->dst_addr4), h->h_addr_list[0], sizeof(p->dst_addr4));
        }

    if(!p->raw){
        p->fd = socket(AF_INET, SOCK_DGRAM, 0);
        if (p->fd < 0) {
            fprintf(stderr, "Socket error\n");
            return -1;
        }
        if (setsockopt(p->fd, SOL_SOCKET, SO_REUSEADDR, (char *) &reuse, 
                sizeof(reuse)) != 0) {
            fprintf(stderr, "setsockopt error: SO_REUSEADDR\n");
            return -1;
        }
#ifdef SO_REUSEPORT
        if (setsockopt(p->fd, SOL_SOCKET, SO_REUSEPORT, (char *) &reuse,
             sizeof(reuse)) != 0) {
            fprintf(stderr, "setsockopt error: SO_REUSEPORT\n");
            return -1;
        }
#endif

                if(IN_MULTICAST(ntohl(p->dst_addr4.s_addr))) {
                        struct ip_mreq  imr;

                        imr.imr_multiaddr.s_addr = p->dst_addr4.s_addr;
                        imr.imr_interface.s_addr = 0;

                        if(setsockopt(p->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) &imr, sizeof(struct ip_mreq)) != 0) {
                                fprintf(stderr, "setsockopt error: IP_ADD_MEMBERSHIP\n");
                                return -1;
                        }
                        if(setsockopt(p->fd, IPPROTO_IP, IP_MULTICAST_TTL, (char *) &p->ttl, sizeof(p->ttl)) != 0) {
                                fprintf(stderr, "setsockopt error: IP_MULTICAST_TTL\n");
                                return -1;
                        }
                }
        } else { /* PACKET socket */
                p->fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
                if(p->fd < 0) {
                        fprintf(stderr, "Socket error\n");
                        return -1;
                }
        }

    memset(&ifr, 0, sizeof(ifr));
    strcpy(ifr.ifr_name, "eth0");
    
    if(ioctl(p->fd, SIOCGIFADDR, &ifr) != 0){
        fprintf(stderr, "Local address resolution error\n");
        return -1;
    }
    sin = (struct sockaddr_in*) (ifr.ifr_addr.sa_data+2);
    p->src_addr4 = *(struct in_addr*)sin; 
    p->src    = inet_ntoa(p->src_addr4);
    p->eth_index = ifr.ifr_ifindex;

    if(ioctl(p->fd, SIOCGIFNETMASK, &ifr) != 0){
        fprintf(stderr, "Local address netmask resolution error\n");
        return -1;
    }
    sin = (struct sockaddr_in*) (ifr.ifr_netmask.sa_data+2);
    p->src_netmask4 = *(struct in_addr*)sin; 
        
    if(ioctl(p->fd, SIOCGIFHWADDR, &ifr) != 0){
        fprintf(stderr, "MAC resolution error\n");
        return -1;
    }
    memcpy(p->mac, ifr.ifr_hwaddr.sa_data, 6);

    if (!IN_MULTICAST(ntohl(p->dst_addr4.s_addr))) {
        uint32_t dstip;
        uint8_t mac[6];
        
        src_net = p->src_netmask4.s_addr & p->src_addr4.s_addr;
        dst_net = p->src_netmask4.s_addr & p->dst_addr4.s_addr;
        if(src_net == dst_net){
            dstip = p->dst_addr4.s_addr;
        } else {
        /* send to gateway */
            FILE *fp = fopen("/proc/net/route", "r");
            unsigned long int d, g, m;
            int flgs, ref, use, metric, mtu, win, ir;
            int fl=0;
            char devname[64];
            if (fscanf(fp, "%*[^\n]\n") < 0) { /* Skip the first line. */
               /* Empty or missing line, or read error. */
                fprintf(stderr, "Gateway resolution error\n");
                return -1;
            }
            while (1) {
                int r;
                r = fscanf(fp, "%63s%lx%lx%X%d%d%d%lx%d%d%d\n",
                       devname, &d, &g, &flgs, &ref, &use, &metric, &m,
                           &mtu, &win, &ir);
                if (r != 11) {
                    if ((r < 0) && feof(fp)) { /* EOF with no (nonspace) chars read. */
                        break;
                    }
                    fprintf(stderr, "Gateway resolution error!\n");
                    return -1;
                }
                if(!d){
                    fl=1;
                    break;
                }
            }
            if(!fl){
                fprintf(stderr, "Gateway resolution error\n");
                return -1;
            }
            dstip = g;
        }
        memset(mac, 0, 6);

        if(arping(p->src_addr4, *((struct in_addr*) &dstip), mac) != 0){
            fprintf(stderr, "Destination address is not resolved\n");
            return -1;
        }

        memcpy(p->dst_mac, mac, 6);
    }

    return 0;
}


void udp_exit4(struct param * p)
{
    if(!p->raw){
        if (IN_MULTICAST(ntohl(p->dst_addr4.s_addr))) {
            struct ip_mreq  imr;
            imr.imr_multiaddr.s_addr = p->dst_addr4.s_addr;
            imr.imr_interface.s_addr = INADDR_ANY;
            if (setsockopt(p->fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, (char *) &imr, sizeof(struct ip_mreq)) != 0) {
                fprintf(stderr, "setsockopt IP_DROP_MEMBERSHIP\n");
                abort();
            }
        }
    }
    close(p->fd);
}

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