source: MondoRescue/branches/2.2.9/mindi-busybox/networking/udhcp/arpping.c@ 2142

Last change on this file since 2142 was 1765, checked in by Bruno Cornec, 17 years ago

Update to busybox 1.7.2
File size: 3.5 KB
Line 
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
16struct arpMsg {
17 /* Ethernet header */
18 uint8_t h_dest[6]; /* 00 destination ether addr */
19 uint8_t h_source[6]; /* 06 source ether addr */
20 uint16_t h_proto; /* 0c packet type ID field */
21
22 /* ARP packet */
23 uint16_t htype; /* 0e hardware type (must be ARPHRD_ETHER) */
24 uint16_t ptype; /* 10 protocol type (must be ETH_P_IP) */
25 uint8_t hlen; /* 12 hardware address length (must be 6) */
26 uint8_t plen; /* 13 protocol address length (must be 4) */
27 uint16_t operation; /* 14 ARP opcode */
28 uint8_t sHaddr[6]; /* 16 sender's hardware address */
29 uint8_t sInaddr[4]; /* 1c sender's IP address */
30 uint8_t tHaddr[6]; /* 20 target's hardware address */
31 uint8_t tInaddr[4]; /* 26 target's IP address */
32 uint8_t pad[18]; /* 2a pad for min. ethernet payload (60 bytes) */
33} ATTRIBUTE_PACKED;
34
35
36/* Returns 1 if no reply received */
37
38int arpping(uint32_t test_ip, uint32_t from_ip, uint8_t *from_mac, const char *interface)
39{
40 int timeout = 2;
41 int s; /* socket */
42 int rv = 1; /* "no reply received" yet */
43 struct sockaddr addr; /* for interface name */
44 struct arpMsg arp;
45 fd_set fdset;
46 struct timeval tm;
47 unsigned prevTime;
48
49 s = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP));
50 if (s == -1) {
51 bb_perror_msg(bb_msg_can_not_create_raw_socket);
52 return -1;
53 }
54
55 if (setsockopt_broadcast(s) == -1) {
56 bb_perror_msg("cannot setsocketopt on raw socket");
57 goto ret;
58 }
59
60 /* send arp request */
61 memset(&arp, 0, sizeof(arp));
62 memset(arp.h_dest, 0xff, 6); /* MAC DA */
63 memcpy(arp.h_source, from_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.sHaddr, from_mac, 6); /* source hardware address */
71 memcpy(arp.sInaddr, &from_ip, sizeof(from_ip)); /* source IP address */
72 /* tHaddr */ /* target hardware address */
73 memcpy(arp.tInaddr, &test_ip, sizeof(test_ip)); /* target IP address */
74
75 memset(&addr, 0, sizeof(addr));
76 safe_strncpy(addr.sa_data, interface, sizeof(addr.sa_data));
77 if (sendto(s, &arp, sizeof(arp), 0, &addr, sizeof(addr)) < 0)
78 goto ret;
79
80 /* wait for arp reply, and check it */
81 do {
82 int r;
83 prevTime = monotonic_sec();
84 FD_ZERO(&fdset);
85 FD_SET(s, &fdset);
86 tm.tv_sec = timeout;
87 tm.tv_usec = 0;
88 r = select(s + 1, &fdset, NULL, NULL, &tm);
89 if (r < 0) {
90 bb_perror_msg("error on ARPING request");
91 if (errno != EINTR)
92 break;
93 } else if (r) {
94 if (recv(s, &arp, sizeof(arp), 0) < 0)
95 break;
96 if (arp.operation == htons(ARPOP_REPLY)
97 && memcmp(arp.tHaddr, from_mac, 6) == 0
98 && *((uint32_t *) arp.sInaddr) == test_ip
99 ) {
100 rv = 0;
101 break;
102 }
103 }
104 timeout -= monotonic_sec() - prevTime;
105 } while (timeout > 0);
106
107 ret:
108 close(s);
109 DEBUG("%srp reply received for this address", rv ? "No a" : "A");
110 return rv;
111}
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