/*
* Builds and sends a single ARP request to locate the server
*
* Return value:
* 0 on success
* errno on error
*/
static int
netdump_send_arp(in_addr_t dst)
{
struct ether_addr bcast;
struct mbuf *m;
struct arphdr *ah;
int pktlen;
MPASS(nd_ifp != NULL);
/* Fill-up a broadcast address. */
memset(&bcast, 0xFF, ETHER_ADDR_LEN);
m = m_gethdr(M_NOWAIT, MT_DATA);
if (m == NULL) {
printf("netdump_send_arp: Out of mbufs\n");
return (ENOBUFS);
}
pktlen = arphdr_len2(ETHER_ADDR_LEN, sizeof(struct in_addr));
m->m_len = pktlen;
m->m_pkthdr.len = pktlen;
MH_ALIGN(m, pktlen);
ah = mtod(m, struct arphdr *);
ah->ar_hrd = htons(ARPHRD_ETHER);
ah->ar_pro = htons(ETHERTYPE_IP);
ah->ar_hln = ETHER_ADDR_LEN;
ah->ar_pln = sizeof(struct in_addr);
ah->ar_op = htons(ARPOP_REQUEST);
memcpy(ar_sha(ah), IF_LLADDR(nd_ifp), ETHER_ADDR_LEN);
((struct in_addr *)ar_spa(ah))->s_addr = nd_client.s_addr;
bzero(ar_tha(ah), ETHER_ADDR_LEN);
((struct in_addr *)ar_tpa(ah))->s_addr = dst;
return (netdump_ether_output(m, nd_ifp, bcast, ETHERTYPE_ARP));
}
static int send_arp (interface_t *iface, int op, struct in_addr sip,
unsigned char *taddr, struct in_addr tip)
{
struct arphdr *arp;
int arpsize = arphdr_len2 (iface->hwlen, sizeof (struct in_addr));
int retval;
arp = xmalloc (arpsize);
memset (arp, 0, arpsize);
arp->ar_hrd = htons (iface->family);
arp->ar_pro = htons (ETHERTYPE_IP);
arp->ar_hln = iface->hwlen;
arp->ar_pln = sizeof (struct in_addr);
arp->ar_op = htons (op);
memcpy (ar_sha (arp), &iface->hwaddr, arp->ar_hln);
memcpy (ar_spa (arp), &sip, arp->ar_pln);
if (taddr)
memcpy (ar_tha (arp), taddr, arp->ar_hln);
memcpy (ar_tpa (arp), &tip, arp->ar_pln);
retval = send_packet (iface, ETHERTYPE_ARP,
(unsigned char *) arp, arphdr_len (arp));
free (arp);
return (retval);
}
