From 9e64dd72765ddc2583554ebed24eb2c824564838 Mon Sep 17 00:00:00 2001 From: Tom Gundersen Date: Wed, 19 Mar 2014 16:05:44 +0100 Subject: sd-dhcp-client: add fallback subnet masks The DHCP RFC does not require the DHCP server to send a subnet mask, so if it is missing, let's try to use the default subnet masks based on address class. In case the class the address belongs to does not have a default subnet mask, we fail as before. Also improve logging when handling invalid dhcp messages, and simply ignore them rather than stop the whole dhcp client. --- src/libsystemd-network/sd-dhcp-lease.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'src/libsystemd-network/sd-dhcp-lease.c') diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c index e6d80d4c66..159bb502c8 100644 --- a/src/libsystemd-network/sd-dhcp-lease.c +++ b/src/libsystemd-network/sd-dhcp-lease.c @@ -481,3 +481,29 @@ int dhcp_lease_load(const char *lease_file, sd_dhcp_lease **ret) { return 0; } + +int dhcp_lease_set_default_subnet_mask(sd_dhcp_lease *lease) { + uint32_t address; + + assert(lease); + assert(lease->address != INADDR_ANY); + + address = be32toh(lease->address); + + /* fall back to the default subnet masks based on address class */ + + if ((address >> 31) == 0x0) + /* class A, leading bits: 0 */ + lease->subnet_mask = htobe32(0xff000000); + else if ((address >> 30) == 0x2) + /* class B, leading bits 10 */ + lease->subnet_mask = htobe32(0xffff0000); + else if ((address >> 29) == 0x6) + /* class C, leading bits 110 */ + lease->subnet_mask = htobe32(0xffffff00); + else + /* class D or E, no default mask. give up */ + return -ERANGE; + + return 0; +} -- cgit v1.2.3-54-g00ecf