as the different negative values equate to different errors.
Tests against syscall returns and fds are very common and mostly fit
the pattern of this change.
The gain is increased range-exclusion.
RFC4361 requires clients to send a clientid, and specifies that by default
that clientid should be a combination of a machine-static DUID and an
interface-static IAID.
There are several RFC-compliant DUIDs. ndhc uses RFC6355's DUID-UUID,
but chooses not to follow RFC4122 for the UUID and instead simply uses
random bytes from its combined Tausworthe PRNG.
RFC4122 is excessively complex, and 128-bit random values are more than
sufficiently collision-resistant on even large DHCP segments.
ndhc requires a read/writable directory to store the DUID/IAID states. By
default this directory is /etc/ndhc. It exists outside the chroot. The DUID
will be stored in a single file, DUID. The IAIDs exist per-interface and are
stored in files with names similar to IAID-xx:xx:xx:xx:xx:xx, where the xx
values are replaced by the Ethernet hardware address of the interface.
If it is impossible to read or store the DUIDs or IAIDs, ndhc will
fail at start time before it performs any network activity or forks any
subprocesses.
If the host system lacks volatile storage, then a clientid should manually
be specified using the -c or --clientid command arguments.
All this entails is that ndhc needs to check to make sure that if the remote
server sends a dhcp packet with a client identifier, the client identifier
of that packet matches the client identifier that ndhc uses to identify
itself.
If the remote server does not attach a client identifier to its dhcp packets,
then the behavior of ndhc does not change.
types are almost identical (same number of fields, each field has the
same length), so the code worked anyway, but nlattr and rtattr are
distinct.
nlattr is the type/length part of the nlmsg header. rtattr is the
type/length part of the individual rt attribute items attached after
a nlmsg.
Use the correct rtattr type, and use the standard macros where appropriate.
manually be set to an 'up' state before much of anything can be changed.
Ensure that this is done very early in ndhc's lifetime, and record the
link status at startup time so that the hardware link status monitoring
will not get confused. A perform_ifup() function is added to faciliate
this need.
Handle nl_getifdata() and get_if_index_and_mac() separately from the
hardware link status monitoring; don't call get_if_index_and_mac() from
nl_process_msgs().
Create the permanent ndhc-master cs.nlFd socket for hardware link status
monitoring after forking subprocesses.
being updated, so perform status debouncing.
While ifch is doing work, the netlink events are ignored. Once ifch has
finished its work, netlink events are no longer ignored. Making this
work requires ifch to communicate back to ndhc, but it is no problem
since the necessary pipes are already in place for IPC.
DHCP-assigned IP, broadcast, and subnet.
The nl_foreach_nlmsg() gains a seq parameter that when set to non-0 will
cause nl_foreach_nlmsg() to ignore any nlmsg that has a seq number
that does not match the caller-supplied seq argument.
sure that it matches that of our associated DHCP server.
Normalize, prune, and beautify the appearance of log messages.
Minor cosmetic cleanups/refactoring.
initialization. Fetching if/address/index/mac mappings is done only once at
program init, so it is done synchronously as an exception to this rule.
Rewrite the netlink handling. Now uses NIH code that should be safe, small,
and correct. No external deps FTW.
running. ndhc does its job entirely with raw sockets before a lease is
established, so it will work just fine, and this change allows for the dhcp
client to be re-run without causing downtime on an interface.
Handle EAGAIN and EWOULDBLOCK more gracefully when dealing with safe_read().
All occurrences of safe_read() should only be invoked on fds that have signaled
ready-to-read state via the epoll() mechanism, so this change should not
result in any observable difference, but it is best to be safe.
Additionally, a constant stack variable is converted to an equivalent
macro define for cleanliness.
Finally, print the error type encountered if reading data from an ARP response
fails with a read error.
Handle failure to create arp sockets more gracefully.
Add initial support for retransmitting arp requests if no reply is met after
a certain number of spurious packets.
the currently assigned gateway/router still replies to ARP queries. If so,
keep the lease. If not, get a new lease.
Save the IP address of the current gateway/router.
Remove an outdated check for a buggy compiler.
Fix a typo in the previous commit that caused timeouts to be 1000x faster than
they should be.
