/*
* Parse a DHCP response packet
* Returns:
* 0 = Unexpected packet, not parsed
* 2 = DHCPOFFER (from dhcp_proto.h)
* 5 = DHCPACK
* 6 = DHCPNACK
*/
static int dhcp_parse(struct netdev *dev, struct bootp_hdr *hdr,
uint8_t *exts, int extlen)
{
uint8_t type = 0;
uint32_t serverid = INADDR_NONE;
int ret = 0;
if (extlen >= 4 && exts[0] == 99 && exts[1] == 130 &&
exts[2] == 83 && exts[3] == 99) {
uint8_t *ext;
for (ext = exts + 4; ext - exts < extlen;) {
uint8_t len, *opt = ext++;
if (*opt == 0)
continue;
len = *ext++;
ext += len;
if (*opt == 53)
type = opt[2];
if (*opt == 54)
memcpy(&serverid, opt + 2, 4);
}
}
switch (type) {
case DHCPOFFER:
ret = bootp_parse(dev, hdr, exts, extlen) ? DHCPOFFER : 0;
if (ret == DHCPOFFER && serverid != INADDR_NONE)
dev->serverid = serverid;
dprintf("\n dhcp offer\n");
break;
case DHCPACK:
ret = bootp_parse(dev, hdr, exts, extlen) ? DHCPACK : 0;
dprintf("\n dhcp ack\n");
break;
case DHCPNAK:
ret = DHCPNAK;
dprintf("\n dhcp nak\n");
break;
}
return ret;
}
/*
* Parse a DHCP response packet
* Returns:
* 0 = Unexpected packet, not parsed
* 2 = DHCPOFFER (from dhcp_proto.h)
* 5 = DHCPACK
* 6 = DHCPNACK
*/
static int dhcp_parse(struct netdev *dev, struct bootp_hdr *hdr,
uint8_t *exts, int extlen)
{
uint8_t type = 0;
uint32_t serverid = INADDR_NONE;
uint32_t leasetime = 0;
int ret = 0;
if (extlen >= 4 && exts[0] == 99 && exts[1] == 130 &&
exts[2] == 83 && exts[3] == 99) {
uint8_t *ext;
for (ext = exts + 4; ext - exts < extlen;) {
int len;
uint8_t opt = *ext++;
if (opt == 0)
continue;
else if (opt == 255)
break;
if (ext - exts >= extlen)
break;
len = *ext++;
if (ext - exts + len > extlen)
break;
switch (opt) {
case 51: /* IP Address Lease Time */
if (len == 4)
leasetime = ntohl(*(uint32_t *)ext);
break;
case 53: /* DHCP Message Type */
if (len == 1)
type = *ext;
break;
case 54: /* Server Identifier */
if (len == 4)
memcpy(&serverid, ext, 4);
break;
}
ext += len;
}
}
switch (type) {
case DHCPOFFER:
ret = bootp_parse(dev, hdr, exts, extlen) ? DHCPOFFER : 0;
if (ret == DHCPOFFER && serverid != INADDR_NONE)
dev->serverid = serverid;
dprintf("\n dhcp offer\n");
break;
case DHCPACK:
dev->dhcpleasetime = leasetime;
ret = bootp_parse(dev, hdr, exts, extlen) ? DHCPACK : 0;
dprintf("\n dhcp ack\n");
break;
case DHCPNAK:
ret = DHCPNAK;
dprintf("\n dhcp nak\n");
break;
}
return ret;
}
