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

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    Revision 532 - (show 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 /* 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 }