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Add Conn and DNS protocol script documentation. (fixes #731)

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This commit is contained in:
Jon Siwek 2012-01-09 14:23:24 -06:00
parent f389fb42c3
commit 62d012e04a
7 changed files with 148 additions and 64 deletions
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71
scripts/base/protocols/dns/consts.bro
View file

@ -4,9 +4,9 @@
module DNS;
export {
const PTR = 12;
const EDNS = 41;
const ANY = 255;
const PTR = 12; ##< RR TYPE value for a domain name pointer.
const EDNS = 41; ##< An OPT RR TYPE value described by EDNS.
const ANY = 255; ##< A QTYPE value describing a request for all records.
## Mapping of DNS query type codes to human readable string representation.
const query_types = {
@ -29,50 +29,43 @@ export {
[ANY] = "*",
} &default = function(n: count): string { return fmt("query-%d", n); };
const code_types = {
[0] = "X0",
[1] = "Xfmt",
[2] = "Xsrv",
[3] = "Xnam",
[4] = "Ximp",
[5] = "X[",
} &default="?";
## Errors used for non-TSIG/EDNS types.
const base_errors = {
[0] = "NOERROR", ##< No Error
[1] = "FORMERR", ##< Format Error
[2] = "SERVFAIL", ##< Server Failure
[3] = "NXDOMAIN", ##< Non-Existent Domain
[4] = "NOTIMP", ##< Not Implemented
[5] = "REFUSED", ##< Query Refused
[6] = "YXDOMAIN", ##< Name Exists when it should not
[7] = "YXRRSET", ##< RR Set Exists when it should not
[8] = "NXRRSet", ##< RR Set that should exist does not
[9] = "NOTAUTH", ##< Server Not Authoritative for zone
[10] = "NOTZONE", ##< Name not contained in zone
[11] = "unassigned-11", ##< available for assignment
[12] = "unassigned-12", ##< available for assignment
[13] = "unassigned-13", ##< available for assignment
[14] = "unassigned-14", ##< available for assignment
[15] = "unassigned-15", ##< available for assignment
[16] = "BADVERS", ##< for EDNS, collision w/ TSIG
[17] = "BADKEY", ##< Key not recognized
[18] = "BADTIME", ##< Signature out of time window
[19] = "BADMODE", ##< Bad TKEY Mode
[20] = "BADNAME", ##< Duplicate key name
[21] = "BADALG", ##< Algorithm not supported
[22] = "BADTRUNC", ##< draft-ietf-dnsext-tsig-sha-05.txt
[3842] = "BADSIG", ##< 16 <= number collision with EDNS(16);
##< this is a translation from TSIG(16)
[0] = "NOERROR", # No Error
[1] = "FORMERR", # Format Error
[2] = "SERVFAIL", # Server Failure
[3] = "NXDOMAIN", # Non-Existent Domain
[4] = "NOTIMP", # Not Implemented
[5] = "REFUSED", # Query Refused
[6] = "YXDOMAIN", # Name Exists when it should not
[7] = "YXRRSET", # RR Set Exists when it should not
[8] = "NXRRSet", # RR Set that should exist does not
[9] = "NOTAUTH", # Server Not Authoritative for zone
[10] = "NOTZONE", # Name not contained in zone
[11] = "unassigned-11", # available for assignment
[12] = "unassigned-12", # available for assignment
[13] = "unassigned-13", # available for assignment
[14] = "unassigned-14", # available for assignment
[15] = "unassigned-15", # available for assignment
[16] = "BADVERS", # for EDNS, collision w/ TSIG
[17] = "BADKEY", # Key not recognized
[18] = "BADTIME", # Signature out of time window
[19] = "BADMODE", # Bad TKEY Mode
[20] = "BADNAME", # Duplicate key name
[21] = "BADALG", # Algorithm not supported
[22] = "BADTRUNC", # draft-ietf-dnsext-tsig-sha-05.txt
[3842] = "BADSIG", # 16 <= number collision with EDNS(16);
# this is a translation from TSIG(16)
} &default = function(n: count): string { return fmt("rcode-%d", n); };
# This deciphers EDNS Z field values.
## This deciphers EDNS Z field values.
const edns_zfield = {
[0] = "NOVALUE", # regular entry
[32768] = "DNS_SEC_OK", # accepts DNS Sec RRs
} &default="?";
## Possible values of the CLASS field in resource records or QCLASS field
## in query messages.
const classes = {
[1] = "C_INTERNET",
[2] = "C_CSNET",
@ -81,4 +74,4 @@ export {
[254] = "C_NONE",
[255] = "C_ANY",
} &default = function(n: count): string { return fmt("qclass-%d", n); };
}
}

54
scripts/base/protocols/dns/main.bro
View file

@ -1,38 +1,80 @@
##! Base DNS analysis script which tracks and logs DNS queries along with
##! their responses.
@load ./consts
module DNS;
export {
## The DNS logging stream identifier.
redef enum Log::ID += { LOG };
## The record type which contains the column fields of the DNS log.
type Info: record {
## The earliest time at which a DNS protocol message over the
## associated connection is observed.
ts: time &log;
## A unique identifier of the connection over which DNS messages
## are being transferred.
uid: string &log;
## The connection's 4-tuple of endpoint addresses/ports.
id: conn_id &log;
## The transport layer protocol of the connection.
proto: transport_proto &log;
## A 16 bit identifier assigned by the program that generated the
## DNS query. Also used in responses to match up replies to
## outstanding queries.
trans_id: count &log &optional;
## The domain name that is the subject of the DNS query.
query: string &log &optional;
## The QCLASS value specifying the class of the query.
qclass: count &log &optional;
## A descriptive name for the class of the query.
qclass_name: string &log &optional;
## A QTYPE value specifying the type of the query.
qtype: count &log &optional;
## A descriptive name for the type of the query.
qtype_name: string &log &optional;
## The response code value in DNS response messages.
rcode: count &log &optional;
## A descriptive name for the response code value.
rcode_name: string &log &optional;
## Whether the message is a query (F) or response (T).
QR: bool &log &default=F;
## The Authoritative Answer bit for response messages specifies that
## the responding name server is an authority for the domain name
## in the question section.
AA: bool &log &default=F;
## The Truncation bit specifies that the message was truncated.
TC: bool &log &default=F;
## The Recursion Desired bit indicates to a name server to recursively
## purse the query.
RD: bool &log &default=F;
## The Recursion Available bit in a response message indicates if
## the name server supports recursive queries.
RA: bool &log &default=F;
## A reserved field that is currently supposed to be zero in all
## queries and responses.
Z: count &log &default=0;
## The set of resource descriptions in answer of the query.
answers: vector of string &log &optional;
## The caching intervals of the associated RRs described by the
## ``answers`` field.
TTLs: vector of interval &log &optional;
## This value indicates if this request/response pair is ready to be logged.
## This value indicates if this request/response pair is ready to be
## logged.
ready: bool &default=F;
## The total number of resource records in a reply message's answer
## section.
total_answers: count &optional;
## The total number of resource records in a reply message's answer,
## authority, and additional sections.
total_replies: count &optional;
};
## A record type which tracks the status of DNS queries for a given
## :bro:type:`connection`.
type State: record {
## Indexed by query id, returns Info record corresponding to
## query/response which haven't completed yet.
@ -44,11 +86,21 @@ export {
finished_answers: set[count] &optional;
};
## An event that can be handled to access the :bro:type:`DNS::Info`
## record as it is sent to the logging framework.
global log_dns: event(rec: Info);
## This is called by the specific dns_*_reply events with a "reply" which
## may not represent the full data available from the resource record, but
## it's generally considered a summarization of the response(s).
##
## c: The connection record for which to fill in DNS reply data.
##
## msg: The DNS message header information for the response.
##
## ans: The general information of a RR response.
##
## reply: The specific response information according to RR type/class.
global do_reply: event(c: connection, msg: dns_msg, ans: dns_answer, reply: string);
}