1. pcap_get_selectable_fd() may return -1 for some devices, even if the
platform as a whole supports select() on these handles. Check for
this condition throughout.
2. The various backend system calls (kevent, poll, epoll, etc.) do not
sleep for the timeout period if no valid handles are registered,
unlike select on UNIX. This leads to busy wait, looping continuously.
Instead, we call usleep() in those cases.
For platforms without selectable pcap handles (e.g. Windows), the
arrival of data for a pcap read would previously skip checking for any
triggered non-pcap events in that loop iteration. This is not usually a
problem because the next loop will be triggered immediately, picking up
the non-pcap events before any further pcap data arrives. However,
excessive pcap data on a handle in immediate mode might prevent the
engine loop from checking for non-pcap events for long enough to result
in timeouts. Instead, do a non-blocking check for triggered events in
this case and handle those in the same loop iteration.
Make current loglevel and current log callback global
to the library. Attaching them to the nsock pool doesn't
bring any benefit and prevents from logging activity in
code sections that don't have access to a pool (such as
proxy chain specification parsing).
Updated external calls and nsock tests accordingly.
Only FD_SET and FD_CLR were available. Added a FD_ISSET equivalent.
Implemented them as static inline instead of macros for consistency.
These functions abort() if the FD number is higher than FD_SETSIZE
(except on windows where no check is performed).
This prevents nsock from iterating over the whole list of events at
each runloop, thus improving performance.
It made it necessary to have pointers from the msevents to the event
lists they belong to. The patch therefore also changes gh_list from
autonomous containers to embedded structures.
Added unit tests accordingly and cosmetic changes to make things look
more consistent.
Reworked the logging infrastructure to make it more flexible
and consistent.
Updated nmap, nping and ncat accordingly. Nsock log level can
now be adjusted at runtime by pressing d/D in nmap.
http://seclists.org/nmap-dev/2012/q3/56. r29134 already addressed the issue but
was incomplete.
This replaces r29134 with an engine-agnostic approach, and additionally enforces
the reset of IOD flags before use or re-use.
The Nsock select engine stores readiness information in a mask instead
of doing an FD_ISSET against the descriptor every time. This is a good
idea, but it removed a special case in the pre-engines code: in case
PCAP_CAN_DO_SELECT is not defined, we can't do FD_ISSET on the
descriptor because it is -1. Here we check for that occurrence and set
EV_READ in the mask so that a non-blocking pcap read can happen every
iteration.
support for system-specific scalable IO notification facilities without breaking
portability. This initial version comes with an epoll(7)-based engine for Linux
and a select(2)-based fallback engine for all other operating systems.
This required an important refactoring of the library but the external API was
preserved.
The rewrite also tries to bring the coding standards of nmap to nsock.
See http://labs.unix-junkies.org/nsock_engines.html for the details.
