| From e7bfd556c079c8b5e7425aed44abc35925b24043 Mon Sep 17 00:00:00 2001 |
| From: Simon Kelley <simon@thekelleys.org.uk> |
| Date: Mon, 31 Dec 2018 20:51:15 +0000 |
| Subject: [PATCH] Alter DHCP address selection after DECLINE in consec-addr |
| mode. Avoid offering the same address after a recieving a |
| DECLINE message to stop an infinite protocol loop. This has |
| long been done in default address allocation mode: this |
| adds similar behaviour when allocaing addresses |
| consecutively. |
| |
| --- |
| src/dhcp.c | 13 +++++++++++++ |
| src/dhcp6.c | 11 +++++++++-- |
| 2 files changed, 22 insertions(+), 2 deletions(-) |
| |
| diff --git a/src/dhcp.c b/src/dhcp.c |
| index f8d323b..6689f2f 100644 |
| --- a/src/dhcp.c |
| +++ b/src/dhcp.c |
| @@ -754,6 +754,19 @@ int address_allocate(struct dhcp_context *context, |
| if (addr.s_addr == d->router.s_addr) |
| break; |
| |
| + /* in consec-ip mode, skip addresses equal to |
| + the number of addresses rejected by clients. This |
| + should avoid the same client being offered the same |
| + address after it has rjected it. */ |
| + if (option_bool(OPT_CONSEC_ADDR)) |
| + { |
| + if (c->addr_epoch) |
| + { |
| + c->addr_epoch--; |
| + d = context; /* d non-NULL skips the address. */ |
| + } |
| + } |
| + |
| /* Addresses which end in .255 and .0 are broken in Windows even when using |
| supernetting. ie dhcp-range=192.168.0.1,192.168.1.254,255,255,254.0 |
| then 192.168.0.255 is a valid IP address, but not for Windows as it's |
| diff --git a/src/dhcp6.c b/src/dhcp6.c |
| index 3932cc7..f8b09e9 100644 |
| --- a/src/dhcp6.c |
| +++ b/src/dhcp6.c |
| @@ -431,8 +431,15 @@ struct dhcp_context *address6_allocate(struct dhcp_context *context, unsigned c |
| else |
| { |
| if (!temp_addr && option_bool(OPT_CONSEC_ADDR)) |
| - /* seed is largest extant lease addr in this context */ |
| - start = lease_find_max_addr6(c) + serial; |
| + { |
| + /* seed is largest extant lease addr in this context, |
| + skip addresses equal to the number of addresses rejected |
| + by clients. This should avoid the same client being offered the same |
| + address after it has rjected it. */ |
| + start = lease_find_max_addr6(c) + serial + c->addr_epoch; |
| + if (c->addr_epoch) |
| + c->addr_epoch--; |
| + } |
| else |
| { |
| u64 range = 1 + addr6part(&c->end6) - addr6part(&c->start6); |
| -- |
| 1.7.10.4 |
