Implement getifaddrs and freeifaddrs within the libc using socket
control files at the VFS. Add an "address" and "netmask" file to the
lwIP plugin.
Only a single IPv4 address is initially supported, and the broadcast
address returned will never be valid.
Fixes#3439
Start and stop the DHCP state machine as the Nic link-state changes.
Invoke the link state handler during configuration rather than assume
that in the case of a downed link lwIP will defer DHCP until the link
comes up.
Additionally, support static DNS configuration via the "nameserver"
configuration attribute.
Fix#3388
LwIP skips a packet copy by wrapping Nic stream buffer regions in LwIP
pbuf objects. Move from a fixed size array to a potentially unbounded
slab allocator for managing this buffer metadata.
Ref #2335
This patch reintroduces the LwIP stack to libc as a VFS plugin
implementing the socket_fs interface. Rather than use LwIP's socket
emulation layer this plugin interfaces directly to LwIP raw API and is
single threaded.
The internal TCP parameters of the stack are untuned.
Fix#2050Fix#2335
