source: branches/stable/mindi-busybox/networking/udhcp/arpping.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 2.8 KB
Line 
1/*
2 * arpping.c
3 *
4 * Mostly stolen from: dhcpcd - DHCP client daemon
5 * by Yoichi Hariguchi <yoichi@fore.com>
6 */
7
8#include <time.h>
9#include <sys/socket.h>
10#include <netinet/if_ether.h>
11#include <net/if_arp.h>
12#include <netinet/in.h>
13#include <string.h>
14#include <unistd.h>
15#include <errno.h>
16
17#include "dhcpd.h"
18#include "arpping.h"
19#include "common.h"
20
21/* args:    yiaddr - what IP to ping
22 *      ip - our ip
23 *      mac - our arp address
24 *      interface - interface to use
25 * retn:    1 addr free
26 *      0 addr used
27 *      -1 error
28 */
29
30/* FIXME: match response against chaddr */
31int arpping(uint32_t yiaddr, uint32_t ip, uint8_t *mac, char *interface)
32{
33
34    int timeout = 2;
35    int optval = 1;
36    int s;          /* socket */
37    int rv = 1;         /* return value */
38    struct sockaddr addr;       /* for interface name */
39    struct arpMsg   arp;
40    fd_set      fdset;
41    struct timeval  tm;
42    time_t      prevTime;
43
44
45    if ((s = socket (PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP))) == -1) {
46#ifdef IN_BUSYBOX
47        LOG(LOG_ERR, bb_msg_can_not_create_raw_socket);
48#else
49        LOG(LOG_ERR, "Could not open raw socket");
50#endif
51        return -1;
52    }
53
54    if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &optval, sizeof(optval)) == -1) {
55        LOG(LOG_ERR, "Could not setsocketopt on raw socket");
56        close(s);
57        return -1;
58    }
59
60    /* send arp request */
61    memset(&arp, 0, sizeof(arp));
62    memcpy(arp.h_dest, MAC_BCAST_ADDR, 6);      /* MAC DA */
63    memcpy(arp.h_source, mac, 6);           /* MAC SA */
64    arp.h_proto = htons(ETH_P_ARP);         /* protocol type (Ethernet) */
65    arp.htype = htons(ARPHRD_ETHER);        /* hardware type */
66    arp.ptype = htons(ETH_P_IP);            /* protocol type (ARP message) */
67    arp.hlen = 6;                   /* hardware address length */
68    arp.plen = 4;                   /* protocol address length */
69    arp.operation = htons(ARPOP_REQUEST);       /* ARP op code */
70    memcpy(arp.sInaddr, &ip, sizeof(ip));       /* source IP address */
71    memcpy(arp.sHaddr, mac, 6);         /* source hardware address */
72    memcpy(arp.tInaddr, &yiaddr, sizeof(yiaddr));   /* target IP address */
73
74    memset(&addr, 0, sizeof(addr));
75    strcpy(addr.sa_data, interface);
76    if (sendto(s, &arp, sizeof(arp), 0, &addr, sizeof(addr)) < 0)
77        rv = 0;
78
79    /* wait arp reply, and check it */
80    tm.tv_usec = 0;
81    prevTime = uptime();
82    while (timeout > 0) {
83        FD_ZERO(&fdset);
84        FD_SET(s, &fdset);
85        tm.tv_sec = timeout;
86        if (select(s + 1, &fdset, (fd_set *) NULL, (fd_set *) NULL, &tm) < 0) {
87            DEBUG(LOG_ERR, "Error on ARPING request: %m");
88            if (errno != EINTR) rv = 0;
89        } else if (FD_ISSET(s, &fdset)) {
90            if (recv(s, &arp, sizeof(arp), 0) < 0 ) rv = 0;
91            if (arp.operation == htons(ARPOP_REPLY) &&
92                memcmp(arp.tHaddr, mac, 6) == 0 &&
93                *((uint32_t *) arp.sInaddr) == yiaddr) {
94                DEBUG(LOG_INFO, "Valid arp reply receved for this address");
95                rv = 0;
96                break;
97            }
98        }
99        timeout -= uptime() - prevTime;
100        prevTime = uptime();
101    }
102    close(s);
103    DEBUG(LOG_INFO, "%salid arp replies for this address", rv ? "No v" : "V");
104    return rv;
105}
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