Implement better handling of command/response bits whilst decoding and
encoding addresses
Changes:
* Add an enum patty_ax25_frame_cr argument to functions in
src/sock.c which send specific types of frames
* Detect AX.25 version >2.0 based on the command/response SSID bits
* Simplify address copying/encoding by usage of the new function
patty_ax25_addr_copy()
* Implement showing AX.25 version, command/response indicator for
frames in src/print.c
Implement better handling of situations when read() captures multiple
TNC frames; ensure each frame is handled in src/server.c, function
handle_iface(), to ensure packets aren't ignored before the next
select() call
Changes:
* Split patty_ax25_frame_decode() into the following:
- patty_ax25_frame_decode_address()
- patty_ax25_frame_decode_control()
This allows for look up an established socket for a given address
pair, to determine if an SABME session is in progress,
necessitating modulo-128 control decoding
* Decode I and S N(R), N(S) sequence numbers, poll/final
bits properly in both modulo-8 and modulo-128 mode
* Perform better frame control validation
* Implement the following functions in src/sock.c:
- patty_ax25_sock_send_rr()
- patty_ax25_sock_send_rnr()
- patty_ax25_sock_send_rej()
- patty_ax25_sock_send_srej()
Corresponding functions have been removed from src/server.c
* Implement better functions in src/sock.c for encoding frame
control, with send/receive sequences associated with the socket,
with modulo-128 encoding for SABME sessions
Other changes:
* Move or delete macros from include/patty/ax25/macros.h into
include/patty/ax25.h and include/patty/ax25/frame.h
* Move definitions from include/patty/ax25/proto.h to header file
include/patty/ax25.h
* Perform better bounds checking while decoding frames
* Improve frame control printing in src/print.c; display frame
type names, N(R), (NS) sequence numbers, and poll/final bits
Significantly simplify dictionaries so that dictionary keys are always
uint32_t; this number can be an arbitrary integer, be it a file
descriptor, for instance, or a hashed value
Move raw frame interface capture to patty_ax25_if, patty_ax25_sock; this
resolves the issue wherein only bytes received, not sent, would be
captured by a raw socket bound to a specific interface with setsockopt()
