Squashed commit of the following:
Fix up some final compile isses.
net/netdev: Convert the network down notification logic to use the new wqueue-based notification factility.
net/udp: Convert the UDP readahead notification logic to use the new wqueue-based notification factility.
net/tcp: Convert the TCP readahead notification logic to use the new wqueue-based notification factility.
mm/iob: Convert the IOB notification logic to use the new wqueue-based notification factility.
sched/wqueue: Signals are not good IPCs to support the target poll functionality for several reasons including the amount of data that can be passed with a signal and in the fact that in protected and kernel modes, user threads executing signal handlers in protected, kernel memory is problematic. Instead, convert the same logic to perform the notifications via function callback on the high priority work queue.
Squashed commit of the following:
net/tcp: Add signal notification for the case when UDP read-ahead data is buffered. This is basically of clone of the TCP notification logic with naming adapted for UDP.
net/tcp: Add signal notification for the case when TCP read-ahead data is buffered.
net/utils: return from net_breaklock() was being clobbered.
net/: Replace all calls to iob_alloc() with calls to net_ioballoc() which will release the network lock, if necessary.
net/utils, tcp, include/net: Separate out the special IOB allocation logic and place it in its own function. Prototype is available in a public header file where it can also be used by network drivers.
net/utils: net_timedwait() now uses new net_breaklock() and net_restorelock().
net/netdev: Add implementation of if_nametoindex() and if indextoname().
net/pkt: Raw AF_PACKET sockets now depend on CONFIG_NETDEV_IFINDEX.
net/procfs: Tweak to handle traversal of interfaces if CONFIG_NETDEV_IFINDEX is not defined.
net/netdev.h: Update netdev_findbyaddr() to use the assigned device index.
Trivial typo fix
net/netdev: Add support for assigned an interface index to a device when it is regisgtered.
Squashed commit of the following:
sched: Rename all use of system_t to clock_t.
syscall: Rename all use of system_t to clock_t.
net: Rename all use of system_t to clock_t.
libs: Rename all use of system_t to clock_t.
fs: Rename all use of system_t to clock_t.
drivers: Rename all use of system_t to clock_t.
arch: Rename all use of system_t to clock_t.
include: Remove definition of systime_t; rename all use of system_t to clock_t.
This commit adds logic to first check for UDP connection mode. If the UDP socket is connected, then the NULL 'to' address is ignored and saved connection address is used instead.
In connection-mode UDP sockets, a remote address is retained in the UDP connection structure. This determines both there send() will send the packets and which packets recv() will accept.
This same mechanism is used for connection-less UDP sendto: A temporary remote address is written into the connection structure to support the sendto() operation. That address persists until the next recvfrom() when it is reset to accept any address.
When UDP read-ahead buffering is enabled, however, that means that the old, invalid remote address can be left in the connection structure for some time. This can cause read-ahead buffer to fail, dropping UDP packets.
Shortening the time between when he remote address is reset (i.e., immediately after the sendto() completes) is not a solution, that does not eliminate the race condition; in only makes it smaller.
With this change, a flag was added to the connection structure to indicate if the UDP socket is in connection mode or if it is connection-less. This change effects only UDP receive operations: The remote address in the UDP connection is always ignored if the UDP socket is not in connection-mode.
No for connection-mode sockets, that remote address behaves as before. But for connection-less sockets, it is only used by sendto().
Gregory Nutt