Pi-Hole/dnsmasq
1
0
Fork 0
mirror of https://github.com/pi-hole/dnsmasq.git synced 2025-12-19 18:28:25 +00:00
Code Issues Packages Projects Releases Wiki Activity

--dhcp-reply-delay option to workaround PXE client bugs.

Browse Source 
Adds option to delay replying to DHCP packets by one or more seconds.
This provides a workaround for a PXE boot firmware implementation
that has a bug causing it to fail if it receives a (proxy) DHCP
reply instantly.

On Linux it looks up the exact receive time of the UDP packet with
the SIOCGSTAMP ioctl to prevent multiple delays if multiple packets
come in around the same time.
This commit is contained in:
Floris Bos
2017-04-09 23:07:13 +01:00
committed by Simon Kelley
parent 60704f5e2e
commit 503c609149
8 changed files with 158 additions and 57 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
src/rfc2131.c
View File

@@ -64,9 +64,10 @@ static int prune_vendor_opts(struct dhcp_netid *netid);
static struct dhcp_opt *pxe_opts(int pxe_arch, struct dhcp_netid *netid, struct in_addr local, time_t now);
struct dhcp_boot *find_boot(struct dhcp_netid *netid);
static int pxe_uefi_workaround(int pxe_arch, struct dhcp_netid *netid, struct dhcp_packet *mess, struct in_addr local, time_t now, int pxe);
static void apply_delay(u32 xid, time_t recvtime, struct dhcp_netid *netid);
size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
size_t sz, time_t now, int unicast_dest, int *is_inform, int pxe, struct in_addr fallback)
size_t sz, time_t now, int unicast_dest, int *is_inform, int pxe, struct in_addr fallback, time_t recvtime)
{
unsigned char *opt, *clid = NULL;
struct dhcp_lease *ltmp, *lease = NULL;
@@ -918,6 +919,8 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
log_packet("PXE", NULL, emac, emac_len, iface_name, ignore ? "proxy-ignored" : "proxy", NULL, mess->xid);
log_tags(tagif_netid, ntohl(mess->xid));
if (!ignore)
apply_delay(mess->xid, recvtime, tagif_netid);
return ignore ? 0 : dhcp_packet_size(mess, agent_id, real_end);
}
}
@@ -1058,7 +1061,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
}
log_tags(tagif_netid, ntohl(mess->xid));
apply_delay(mess->xid, recvtime, tagif_netid);
log_packet("DHCPOFFER" , &mess->yiaddr, emac, emac_len, iface_name, NULL, NULL, mess->xid);
time = calc_time(context, config, option_find(mess, sz, OPTION_LEASE_TIME, 4));
@@ -2626,6 +2629,29 @@ static void do_options(struct dhcp_context *context,
}
}
static void apply_delay(u32 xid, time_t recvtime, struct dhcp_netid *netid)
{
struct delay_config *delay_conf;
/* Decide which delay_config option we're using */
for (delay_conf = daemon->delay_conf; delay_conf; delay_conf = delay_conf->next)
if (match_netid(delay_conf->netid, netid, 0))
break;
if (!delay_conf)
/* No match, look for one without a netid */
for (delay_conf = daemon->delay_conf; delay_conf; delay_conf = delay_conf->next)
if (match_netid(delay_conf->netid, netid, 1))
break;
if (delay_conf)
{
if (!option_bool(OPT_QUIET_DHCP))
my_syslog(MS_DHCP | LOG_INFO, _("%u reply delay: %d"), ntohl(xid), delay_conf->delay);
delay_dhcp(recvtime, delay_conf->delay, -1, 0, 0);
}
}
#endif