#include <stdio.h>
#include <net/ethernet.h>
#include <sys/param.h>
+#include <sys/ioctl.h>
#include "util.h"
#include "list.h"
size_t *optlen) {
int r;
- r = dhcp_message_init(message, BOOTREQUEST, client->xid, type,
- secs, opt, optlen);
+ assert(secs);
+
+ r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt,
+ optlen);
if (r < 0)
return r;
+ /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
+ refuse to issue an DHCP lease if 'secs' is set to zero */
+ message->secs = htobe16(secs);
+
memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
if (client->state == DHCP_STATE_RENEWING ||
if (err < 0)
return err;
- dhcp_packet_append_ip_headers(discover, BOOTREQUEST, len);
+ dhcp_packet_append_ip_headers(discover, len);
err = dhcp_network_send_raw_socket(client->fd, &client->link,
discover, len);
&request->dhcp,
len - DHCP_IP_UDP_SIZE);
} else {
- dhcp_packet_append_ip_headers(request, BOOTREQUEST, len);
+ dhcp_packet_append_ip_headers(request, len);
err = dhcp_network_send_raw_socket(client->fd, &client->link,
request, len);
assert(client->event);
assert(message);
- if (be32toh(message->xid) != client->xid)
+ if (len < DHCP_MESSAGE_SIZE) {
+ log_dhcp_client(client, "message too small (%d bytes): "
+ "ignoring", len);
+ return 0;
+ }
+
+ if (message->op != BOOTREPLY) {
+ log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
return 0;
+ }
+
+ if (be32toh(message->xid) != client->xid) {
+ log_dhcp_client(client, "received xid (%u) does not match "
+ "expected (%u): ignoring",
+ be32toh(message->xid), client->xid);
+ return 0;
+ }
if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
- ETHER_ADDR_LEN))
+ ETHER_ADDR_LEN)) {
+ log_dhcp_client(client, "received chaddr does not match "
+ "expected: ignoring");
return 0;
+ }
switch (client->state) {
case DHCP_STATE_SELECTING:
static int client_receive_message_udp(sd_event_source *s, int fd,
uint32_t revents, void *userdata) {
sd_dhcp_client *client = userdata;
- uint8_t buf[sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE];
- int buflen = sizeof(buf);
- int len, r = 0;
+ _cleanup_free_ DHCPMessage *message = NULL;
+ int buflen = 0, len, r;
usec_t time_now;
assert(s);
assert(client);
assert(client->event);
- len = read(fd, &buf, buflen);
+ r = ioctl(fd, FIONREAD, &buflen);
+ if (r < 0 || buflen <= 0)
+ buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE;
+
+ message = malloc0(buflen);
+ if (!message)
+ return -ENOMEM;
+
+ len = read(fd, message, buflen);
if (len < 0)
return 0;
if (r < 0)
return client_stop(client, r);
- return client_handle_message(client, (DHCPMessage *) buf, len,
+ return client_handle_message(client, message, len,
time_now);
}
static int client_receive_message_raw(sd_event_source *s, int fd,
uint32_t revents, void *userdata) {
sd_dhcp_client *client = userdata;
- uint8_t buf[sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE];
- int buflen = sizeof(buf);
- int len, r = 0;
- DHCPPacket *packet;
+ _cleanup_free_ DHCPPacket *packet = NULL;
+ int buflen = 0, len, r;
usec_t time_now;
assert(s);
assert(client);
assert(client->event);
- len = read(fd, &buf, buflen);
+ r = ioctl(fd, FIONREAD, &buflen);
+ if (r < 0 || buflen <= 0)
+ buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
+
+ packet = malloc0(buflen);
+ if (!packet)
+ return -ENOMEM;
+
+ len = read(fd, packet, buflen);
if (len < 0)
return 0;
- packet = (DHCPPacket *) buf;
-
- r = dhcp_packet_verify_headers(packet, BOOTREPLY, len);
+ r = dhcp_packet_verify_headers(packet, len);
if (r < 0)
return 0;