diff options
| author | Baptiste Jonglez <git@bitsofnetworks.org> | 2015-09-14 12:25:33 +0200 |
|---|---|---|
| committer | Felix Fietkau <nbd@openwrt.org> | 2015-09-26 13:50:48 +0200 |
| commit | a0f133ed22dee4eccc05961f646e14ecc0514060 (patch) | |
| tree | 0a1dd925456d609167e3e6ff6db2b1fd72e5174a /interface-ip.c | |
| parent | 014698606902e495c7b169bf30688a685cd72d64 (diff) | |
interface-ip: Fix broadcast address when using /31 or /32 IPv4 addressing
A /31-addressed interface requires a broadcast address of 255.255.255.255,
because there is no room for a proper broadcast address. Without this,
any packet destinated to the other end of the link is sent as broadcast,
which is incorrect.
For consistency with the Linux kernel, /32-addressed interfaces are
treated in the same way.
Signed-off-by: Baptiste Jonglez <git@bitsofnetworks.org>
Diffstat (limited to 'interface-ip.c')
| -rw-r--r-- | interface-ip.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/interface-ip.c b/interface-ip.c index 4a2ee35..54f56d6 100644 --- a/interface-ip.c +++ b/interface-ip.c @@ -473,11 +473,17 @@ interface_update_proto_addr(struct vlist_tree *tree, if ((a_new->flags & DEVADDR_FAMILY) == DEVADDR_INET4 && !a_new->broadcast) { - uint32_t mask = ~0; - uint32_t *a = (uint32_t *) &a_new->addr; - - mask >>= a_new->mask; - a_new->broadcast = *a | htonl(mask); + /* /31 and /32 addressing need 255.255.255.255 + * as broadcast address. */ + if (a_new->mask >= 31) { + a_new->broadcast = (uint32_t) ~0; + } else { + uint32_t mask = ~0; + uint32_t *a = (uint32_t *) &a_new->addr; + + mask >>= a_new->mask; + a_new->broadcast = *a | htonl(mask); + } } } |