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EPAN CHILDREN
This document is a work in progress.
This document describes a potential interface between a master process and one or more working children.
The goal is to have along-running epan process without the troubles of epan reinit (leaks, mis-reinits, ...).
Working children are spawn to capture or read files, then terminated.
The long running parent process initializes epan and forks children that require no further initialization to run.
epan_child.h in the root directory describes the C interface.
Appendix A
ECHLD PROTOCOL INTERACTION DIAGRAMS
parent child dumpcap
| | |
A.1. creation
new_child() ---------->|
|<-----HELLO------|
IDLE
A.2. keepalive
A.2.1 p->c
ANY_STATE
|-------PING----->|
|<------PONG------|
SAME_STATE
A.2.2 c->p
ANY_STATE
|<------PING------|
|-------PONG----->|
SAME_STATE
A.3. destruction
A.3.1 normal
ANY_STATE
|---CLOSE_CHILD-->|
|<----CLOSING-----|
DYING
|<-- SIG_CHLD
delete_child()
A.3.2 fatal error
ANY_STATE
|<-----ERROR------| (fatal_err,"reason")
|<---SIG_CHLD
delete_child()
A.3.3 crash
ANY_STATE
|<---SIG_CHLD
delete_child()
A.4. getting current dir
ANY_STATE
|-------PWD------>|
|<------CWD-------| (dirname)
SAME_STATE
A.5. changing current dir
A.5.1 dir changed ok
ANY_STATE
|------CHDIR----->| (dirname)
|<------CWD-------| (dirname)
SAME_STATE
A.5.2 dir changed ko
ANY_STATE
|------CHDIR----->| (dirname)
|<-----ERROR------| (cannot_cd, "reason")
SAME_STATE
A.6. listing current directory
A.6.1 file list ok
ANY_STATE
|----LIST_FILES-->| ("*.*"")
|<---FILE_INFO----| (filename, format, encap, num_pkts, ...);
|<---FILE_INFO----| (filename, format, encap, num_pkts, ...);
.....
|<---FILE_INFO----| (filename, format, encap, num_pkts, ...);
SAME_STATE
A.6.2 file list ko
ANY_STATE
|----LIST_FILES-->| ("*.*"")
|<-----ERROR------| (no_files, "reason")
SAME_STATE
A.7. opening a file
A.7.1 opened ok
IDLE
|----OPEN_FILE---->| (filename, ...)
|<---FILE_OPENED---| (dirname)
READING
A.7.2 not opened
IDLE
|----OPEN_FILE---->| (filename, ...)
|<-----ERROR-------| (cannot_open, "reason")
IDLE
A.8. saving a file
A.8.1 save ok
READING/CAPTURING/DONE
|-----SAVE_FILE---->| ("new_filename",opts,...)
|<----FILE_SAVED----| (24, tree)
SAME_STATE
A.8.1 save ko
READING/CAPTURING/DONE
|-----SAVE_FILE---->| ("new_filename",opts,...)
|<------ERROR-------| (cannot_save, "reason")
SAME_STATE
A.9. listing interfaces
A.9.1 intf list ok
IDLE
|--LIST_INTERFACES-->| ("*.*"")
| |-------????------>|
| |<------????-------|
|<--INTERFACE_INFO---| (name, param1=val1, ...)
|<--INTERFACE_INFO---| (name, param1=val1, ...)
.....
|<--INTERFACE_INFO---| (name, param1=val1, ...)
IDLE
A.9.2 intf list ko
|--LIST_INTERFACES-->| ("*.*"")
| |-------????------>|
| |<------????-------|
|<------ERROR-------| (list_intf, "reason")
A.10. opening an interface
A.10.1 interface opened ok
IDLE
|---OPEN_INTERFACE-->|
| |-------????------>|
| |<------????-------|
|<--INTERFACE_OPENED-|
READY
A.10.2 interface open failure
IDLE
|--OPEN_INTERFACE--->|
| |-------????------>|
| |<------????-------|
|<-------ERROR-------| (intf, "reason")
IDLE
A.11. starting capture
A.11.1 started capture ok
READY
|---START_CAPTURE--->|
| |-------????------>|
| |<------????-------|
|<-CAPTURE_STARTED---|
IN_CAPTURE
A.11.2 capture start failure
READY
|----START_CAPTURE-->|
| |-------????------>|
| |<------????-------|
|<-------ERROR-------| (cannot_start, "reason")
READY
A.12. capturing or reading
IN_CAPTURE/READING
| |<------????-------|
|<----PACKET_SUM-----| (framenum, columns)
IN_CAPTURE
A.13 getting packet details
A.13.1 just frame
IN_CAPTURE/READING
|----GET_PACKETS--->| (framelist)
|<-----PACKET-------| (1, tree)
|<-----BUFFER-------| ("1", tvb)
|<-----PACKET-------| (2, tree)
|<-----BUFFER-------| ("2", tvb)
SAME_STATE
A.13.2 frame with reassembled buffer
IN_CAPTURE/READING/DONE
|----GET_PACKETS--->| (framelist)
|<-----PACKET-------| (framenum, tree)
|<-----BUFFER-------| ("framenum", tvb)
|<-----BUFFER-------| ("reas_num", tvb)
SAME_STATE
A.13.3 frame with known reassembled buffer
IN_CAPTURE/READING/DONE
|<-----PACKET-------| (framenum+N, tree)
|<-----BUFFER-------| ("framenum+N", tvb)
|<-----BUFFER-------| ("reas_num", NULL)
SAME_STATE
A.13.4 buffer request (e.g. un-cached buffer)
IN_CAPTURE/READING/DONE
|------GET_BUF----->| (bufname)
|<-----BUFFER-------| (bufname, NULL)
SAME_STATE
A.14 stpping capture
IN_CAPTURE
|---STOP_CAPTURE--->|
|<-CAPTURE_STOPPED--|
DONE
A.15. done reading
READING
|<-- EOF
|<--------EOF--------|
DONE
A.16 setting a note
A.16.1 note set ok
IN_CAPTURE/READING/DONE
|----ADD_NOTE------>| (framenum,note)
|<----NOTE_ADDED----|
SAME_STATE
A.16.2 note set failure
IN_CAPTURE/READING/DONE
|----ADD_NOTE------>| (framenum,note)
|<----NOTE_ADDED----|
SAME_STATE
A.17 applying a filter
IN_CAPTURE/READING/DONE
|---APPLY_FILTER--->| (dfilter_str)
|<---PACKET_LIST----| (Packet-Range)
|<---PACKET_LIST----| (Packet-Range)
SAME_STATE
A.18 setting a filter
IDLE
|-----SET_FILTER---->| (dfilter_str)
|<---FILTER_SET------|
IDLE
|
