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    Annotation of /trunk/mkinitrd-magellan/busybox/networking/udhcp/arpping.c

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    Revision 532 - (hide annotations) (download)
    Sat Sep 1 22:45:15 2007 UTC (16 years, 8 months ago) by niro
    File MIME type: text/plain
    File size: 3379 byte(s) 
    -import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
    1 niro 532 /* vi: set sw=4 ts=4: */
    2     /*
    3     * arpping.c
    4     *
    5     * Mostly stolen from: dhcpcd - DHCP client daemon
    6     * by Yoichi Hariguchi <yoichi@fore.com>
    7     */
    8    
    9     #include <netinet/if_ether.h>
    10     #include <net/if_arp.h>
    11    
    12     #include "common.h"
    13     #include "dhcpd.h"
    14    
    15    
    16     struct arpMsg {
    17     /* Ethernet header */
    18     uint8_t h_dest[6]; /* destination ether addr */
    19     uint8_t h_source[6]; /* source ether addr */
    20     uint16_t h_proto; /* packet type ID field */
    21    
    22     /* ARP packet */
    23     uint16_t htype; /* hardware type (must be ARPHRD_ETHER) */
    24     uint16_t ptype; /* protocol type (must be ETH_P_IP) */
    25     uint8_t hlen; /* hardware address length (must be 6) */
    26     uint8_t plen; /* protocol address length (must be 4) */
    27     uint16_t operation; /* ARP opcode */
    28     uint8_t sHaddr[6]; /* sender's hardware address */
    29     uint8_t sInaddr[4]; /* sender's IP address */
    30     uint8_t tHaddr[6]; /* target's hardware address */
    31     uint8_t tInaddr[4]; /* target's IP address */
    32     uint8_t pad[18]; /* pad for min. Ethernet payload (60 bytes) */
    33     } ATTRIBUTE_PACKED;
    34    
    35     /* args: yiaddr - what IP to ping
    36     * ip - our ip
    37     * mac - our arp address
    38     * interface - interface to use
    39     * retn: 1 addr free
    40     * 0 addr used
    41     * -1 error
    42     */
    43    
    44     /* FIXME: match response against chaddr */
    45     int arpping(uint32_t yiaddr, uint32_t ip, uint8_t *mac, char *interface)
    46     {
    47     int timeout = 2;
    48     int s; /* socket */
    49     int rv = 1; /* return value */
    50     struct sockaddr addr; /* for interface name */
    51     struct arpMsg arp;
    52     fd_set fdset;
    53     struct timeval tm;
    54     time_t prevTime;
    55    
    56    
    57     s = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP));
    58     if (s == -1) {
    59     bb_perror_msg(bb_msg_can_not_create_raw_socket);
    60     return -1;
    61     }
    62    
    63     if (setsockopt_broadcast(s) == -1) {
    64     bb_perror_msg("cannot setsocketopt on raw socket");
    65     close(s);
    66     return -1;
    67     }
    68    
    69     /* send arp request */
    70     memset(&arp, 0, sizeof(arp));
    71     memcpy(arp.h_dest, MAC_BCAST_ADDR, 6); /* MAC DA */
    72     memcpy(arp.h_source, mac, 6); /* MAC SA */
    73     arp.h_proto = htons(ETH_P_ARP); /* protocol type (Ethernet) */
    74     arp.htype = htons(ARPHRD_ETHER); /* hardware type */
    75     arp.ptype = htons(ETH_P_IP); /* protocol type (ARP message) */
    76     arp.hlen = 6; /* hardware address length */
    77     arp.plen = 4; /* protocol address length */
    78     arp.operation = htons(ARPOP_REQUEST); /* ARP op code */
    79     memcpy(arp.sInaddr, &ip, sizeof(ip)); /* source IP address */
    80     memcpy(arp.sHaddr, mac, 6); /* source hardware address */
    81     memcpy(arp.tInaddr, &yiaddr, sizeof(yiaddr)); /* target IP address */
    82    
    83     memset(&addr, 0, sizeof(addr));
    84     strcpy(addr.sa_data, interface);
    85     if (sendto(s, &arp, sizeof(arp), 0, &addr, sizeof(addr)) < 0)
    86     rv = 0;
    87    
    88     /* wait arp reply, and check it */
    89     tm.tv_usec = 0;
    90     prevTime = uptime();
    91     while (timeout > 0) {
    92     FD_ZERO(&fdset);
    93     FD_SET(s, &fdset);
    94     tm.tv_sec = timeout;
    95     if (select(s + 1, &fdset, (fd_set *) NULL, (fd_set *) NULL, &tm) < 0) {
    96     bb_perror_msg("error on ARPING request");
    97     if (errno != EINTR) rv = 0;
    98     } else if (FD_ISSET(s, &fdset)) {
    99     if (recv(s, &arp, sizeof(arp), 0) < 0 ) rv = 0;
    100     if (arp.operation == htons(ARPOP_REPLY) &&
    101     memcmp(arp.tHaddr, mac, 6) == 0 &&
    102     *((uint32_t *) arp.sInaddr) == yiaddr) {
    103     DEBUG("Valid arp reply received for this address");
    104     rv = 0;
    105     break;
    106     }
    107     }
    108     timeout -= uptime() - prevTime;
    109     prevTime = uptime();
    110     }
    111     close(s);
    112     DEBUG("%salid arp replies for this address", rv ? "No v" : "V");
    113     return rv;
    114     }