On Feb 27, 2012, at 9:40 AM, Nuno Martins wrote:
> I'm having a trouble to find the purpose of pid identifier in grammar.y
> file. #line 398
>
> This identifier is related to what protocol ?
>
> I'm supposing that this pid is not related in any way with processes (like
> pid process identifier), right?
Right.
The grammar rules for pid are
pid: nid
| qid and id
| qid or id
;
so it's either a nid by itself:
nid: ID
| HID '/' NUM
| HID NETMASK HID
| HID
| HID6 '/' NUM
| HID6
| EID
| AID
| not id
;
which is a "network ID" (host name, IPv4 address+netmask, IPv6 address +
CIDRish number, Ethernet ID, ATM ID, or a negated version of any of those), or
it's a qid ANDed or ORed with an id:
qid: pnum
| pid
;
pnum: NUM
| paren pnum ')'
;
id: nid
| pnum
| paren pid ')'
;
The "p" in "pid" presumably refers to Parentheses, not to Protocols or
Processes; the "pid" rule exists not to define a symbol that has some inherent
semantics the user would care about, it just exists to allow the
parenthesization rules of the libpcap expression syntax to be stated.-
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