void arp_handle(unsigned char *src_mac, unsigned char *data, unsigned short len)
{
struct arp_hdr *pkt = (struct arp_hdr *)data;
switch (ntohs(pkt->oper))
{
case ARP_OPER_REQUEST:
#ifdef DEBUG_ARP
printf("ARP Request for %d.%d.%d.%d\n",
pkt->tpa[0], pkt->tpa[1],
pkt->tpa[2], pkt->tpa[3]);
#endif /* DEBUG_ARP */
arp_table_add(pkt->spa, pkt->sha);
if (memcmp(pkt->tpa, ip_address, 4) == 0)
arp_send_reply(src_mac, pkt->sha, pkt->spa, pkt->tpa);
break;
case ARP_OPER_REPLY:
#ifdef DEBUG_ARP
printf("ARP Reply\n");
#endif /* DEBUG_ARP */
arp_table_add(pkt->spa, pkt->sha);
break;
default:
break;
}
}
static void bootp_reply(Slirp *slirp, const struct bootp_t *bp)
{
BOOTPClient *bc = NULL;
struct mbuf *m;
struct bootp_t *rbp;
struct sockaddr_in saddr, daddr;
struct in_addr preq_addr;
int dhcp_msg_type, val;
uint8_t *q;
uint8_t *end;
uint8_t client_ethaddr[ETH_ALEN];
/* extract exact DHCP msg type */
dhcp_decode(bp, &dhcp_msg_type, &preq_addr);
DPRINTF("bootp packet op=%d msgtype=%d", bp->bp_op, dhcp_msg_type);
if (preq_addr.s_addr != htonl(0L))
DPRINTF(" req_addr=%08" PRIx32 "\n", ntohl(preq_addr.s_addr));
else {
DPRINTF("\n");
}
if (dhcp_msg_type == 0)
dhcp_msg_type = DHCPREQUEST; /* Force reply for old BOOTP clients */
if (dhcp_msg_type != DHCPDISCOVER &&
dhcp_msg_type != DHCPREQUEST)
return;
/* Get client's hardware address from bootp request */
memcpy(client_ethaddr, bp->bp_hwaddr, ETH_ALEN);
m = m_get(slirp);
if (!m) {
return;
}
m->m_data += IF_MAXLINKHDR;
rbp = (struct bootp_t *)m->m_data;
m->m_data += sizeof(struct udpiphdr);
memset(rbp, 0, sizeof(struct bootp_t));
if (dhcp_msg_type == DHCPDISCOVER) {
if (preq_addr.s_addr != htonl(0L)) {
bc = request_addr(slirp, &preq_addr, client_ethaddr);
if (bc) {
daddr.sin_addr = preq_addr;
}
}
if (!bc) {
new_addr:
bc = get_new_addr(slirp, &daddr.sin_addr, client_ethaddr);
if (!bc) {
DPRINTF("no address left\n");
return;
}
}
memcpy(bc->macaddr, client_ethaddr, ETH_ALEN);
} else if (preq_addr.s_addr != htonl(0L)) {
bc = request_addr(slirp, &preq_addr, client_ethaddr);
if (bc) {
daddr.sin_addr = preq_addr;
memcpy(bc->macaddr, client_ethaddr, ETH_ALEN);
} else {
/* DHCPNAKs should be sent to broadcast */
daddr.sin_addr.s_addr = 0xffffffff;
}
} else {
bc = find_addr(slirp, &daddr.sin_addr, bp->bp_hwaddr);
if (!bc) {
/* if never assigned, behaves as if it was already
assigned (windows fix because it remembers its address) */
goto new_addr;
}
}
/* Update ARP table for this IP address */
arp_table_add(slirp, daddr.sin_addr.s_addr, client_ethaddr);
saddr.sin_addr = slirp->vhost_addr;
saddr.sin_port = htons(BOOTP_SERVER);
daddr.sin_port = htons(BOOTP_CLIENT);
rbp->bp_op = BOOTP_REPLY;
rbp->bp_xid = bp->bp_xid;
rbp->bp_htype = 1;
rbp->bp_hlen = 6;
memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, ETH_ALEN);
rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */
rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */
q = rbp->bp_vend;
end = (uint8_t *)&rbp[1];
memcpy(q, rfc1533_cookie, 4);
q += 4;
if (bc) {
DPRINTF("%s addr=%08" PRIx32 "\n",
(dhcp_msg_type == DHCPDISCOVER) ? "offered" : "ack'ed",
ntohl(daddr.sin_addr.s_addr));
if (dhcp_msg_type == DHCPDISCOVER) {
*q++ = RFC2132_MSG_TYPE;
*q++ = 1;
*q++ = DHCPOFFER;
} else /* DHCPREQUEST */ {
*q++ = RFC2132_MSG_TYPE;
*q++ = 1;
*q++ = DHCPACK;
}
if (slirp->bootp_filename)
snprintf((char *)rbp->bp_file, sizeof(rbp->bp_file), "%s",
slirp->bootp_filename);
*q++ = RFC2132_SRV_ID;
*q++ = 4;
memcpy(q, &saddr.sin_addr, 4);
q += 4;
*q++ = RFC1533_NETMASK;
*q++ = 4;
memcpy(q, &slirp->vnetwork_mask, 4);
q += 4;
if (!slirp->restricted) {
*q++ = RFC1533_GATEWAY;
*q++ = 4;
memcpy(q, &saddr.sin_addr, 4);
q += 4;
*q++ = RFC1533_DNS;
*q++ = 4;
memcpy(q, &slirp->vnameserver_addr, 4);
q += 4;
}
*q++ = RFC2132_LEASE_TIME;
*q++ = 4;
val = htonl(LEASE_TIME);
memcpy(q, &val, 4);
q += 4;
if (*slirp->client_hostname) {
val = strlen(slirp->client_hostname);
if (q + val + 2 >= end) {
g_warning("DHCP packet size exceeded, "
"omitting host name option.");
} else {
*q++ = RFC1533_HOSTNAME;
*q++ = val;
memcpy(q, slirp->client_hostname, val);
q += val;
}
}
if (slirp->vdomainname) {
val = strlen(slirp->vdomainname);
if (q + val + 2 >= end) {
g_warning("DHCP packet size exceeded, "
"omitting domain name option.");
} else {
*q++ = RFC1533_DOMAINNAME;
*q++ = val;
memcpy(q, slirp->vdomainname, val);
q += val;
}
}
if (slirp->tftp_server_name) {
val = strlen(slirp->tftp_server_name);
if (q + val + 2 >= end) {
g_warning("DHCP packet size exceeded, "
"omitting tftp-server-name option.");
} else {
*q++ = RFC2132_TFTP_SERVER_NAME;
*q++ = val;
memcpy(q, slirp->tftp_server_name, val);
q += val;
}
}
if (slirp->vdnssearch) {
val = slirp->vdnssearch_len;
if (q + val >= end) {
g_warning("DHCP packet size exceeded, "
"omitting domain-search option.");
} else {
memcpy(q, slirp->vdnssearch, val);
q += val;
}
}
} else {
static const char nak_msg[] = "requested address not available";
DPRINTF("nak'ed addr=%08" PRIx32 "\n", ntohl(preq_addr.s_addr));
*q++ = RFC2132_MSG_TYPE;
*q++ = 1;
*q++ = DHCPNAK;
*q++ = RFC2132_MESSAGE;
*q++ = sizeof(nak_msg) - 1;
memcpy(q, nak_msg, sizeof(nak_msg) - 1);
q += sizeof(nak_msg) - 1;
}
assert(q < end);
*q = RFC1533_END;
daddr.sin_addr.s_addr = 0xffffffffu;
m->m_len = sizeof(struct bootp_t) -
sizeof(struct ip) - sizeof(struct udphdr);
udp_output(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
}
