#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 ||
uint8_t *opt;
optlen = DHCP_MIN_OPTIONS_SIZE;
- len = DHCP_MESSAGE_SIZE + optlen;
+ len = sizeof(DHCPPacket) + optlen;
request = malloc0(len);
if (!request)
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;
usec_t time_now;
+ uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
+ struct iovec iov = {};
+ struct msghdr msg = {
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
+ .msg_control = cmsgbuf,
+ .msg_controllen = sizeof(cmsgbuf),
+ };
+ struct cmsghdr *cmsg;
+ bool checksum = true;
+ int buflen = 0, len, r;
assert(s);
assert(client);
assert(client->event);
- len = read(fd, &buf, buflen);
- if (len < 0)
+ r = ioctl(fd, FIONREAD, &buflen);
+ if (r < 0 || buflen <= 0)
+ buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
+
+ packet = malloc0(buflen);
+ if (!packet)
+ return -ENOMEM;
+
+ iov.iov_base = packet;
+ iov.iov_len = buflen;
+
+ len = recvmsg(fd, &msg, 0);
+ if (len < 0) {
+ log_dhcp_client(client, "could not receive message from raw "
+ "socket: %s", strerror(errno));
return 0;
+ }
- packet = (DHCPPacket *) buf;
+ for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+ if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) {
+ struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
+
+ checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
+ break;
+ }
+ }
- r = dhcp_packet_verify_headers(packet, len);
+ r = dhcp_packet_verify_headers(packet, len, checksum);
if (r < 0)
return 0;