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Rewrite edns0 (#561)
* Add edns0 code rewrite * check arg count * change `new`; set EDNS0 if request doesn't have it set * change set to replace_or_append * change to append_or_replace * return error in new * update documents * fixt UT * return error * go fmt * Rework for more general EDNS0 use Also changed how rules are created and validated. Implements EDNS0 NSID in addition to local. * go fmt * README updates, NSID tests and fixes * gofmt -s -w * Fix tests for rewrite syntax change * Add tests, fix error message * Review nits * Missed on nit * More tests, integration test, fix edns0 parse issue * Fix README, use RewriteIgnored * go fmt
This commit is contained in:
John Belamaric
committed by
Miek Gieben
Miek Gieben
parent
d1bb4ea130
commit
ef315ef3e2
@@ -23,79 +23,37 @@ rewritten; e.g., to rewrite CH queries to IN use `rewrite class CH IN`.
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When the FIELD is `name` the query name in the message is rewritten; this
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needs to be a full match of the name, e.g., `rewrite name miek.nl example.org`.
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When the FIELD is `edns0` an EDNS0 option can be appended to the request as described below.
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If you specify multiple rules and an incoming query matches on multiple (simple) rules, only
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the first rewrite is applied.
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## EDNS0 Options
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> Everything below this line has not been implemented, yet.
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Using FIELD edns0, you can set, append, or replace specific EDNS0 options on the request.
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* `replace` will modify any matching (what that means may vary based on EDNS0 type) option with the specified option
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* `append` will add the option regardless of what options already exist
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* `set` will modify a matching option or add one if none is found
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Currently supported are `EDNS0_LOCAL` and `EDNS0_NSID`.
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### `EDNS0_LOCAL`
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This has two fields, code and data. A match is defined as having the same code. Data may be a string, or if
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it starts with `0x` it will be treated as hex. Example:
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~~~
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rewrite [basename] {
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regexp pattern
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ext extensions...
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if a cond b
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status code
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to destinations...
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}
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rewrite edns0 local set 0xffee 0x61626364
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~~~
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* basepath is the base path to match before rewriting with a regular expression. Default is /.
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* regexp (shorthand: r) will match the path with the given regular expression pattern. Extremely high-load servers should avoid using regular expressions.
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* extensions... is a space-separated list of file extensions to include or ignore. Prefix an extension with ! to exclude an extension. The forward slash / symbol matches paths without file extensions.
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* if specifies a rewrite condition. Multiple ifs are AND-ed together. a and b are any string and may use request placeholders. cond is the condition, with possible values explained below.
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* status will respond with the given status code instead of performing a rewrite. In other words, use either "status" or "to" in your rule, but not both. The code must be a number in the format 2xx or 4xx.
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* destinations... is one or more space-separated paths to rewrite to, with support for request placeholders as well as numbered regular expression captures such as {1}, {2}, etc. Rewrite will check each destination in order and rewrite to the first destination that exists. Each one is checked as a file or, if it ends with /, as a directory. The last destination will act as the default if no other destination exists.
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"if" Conditions
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The if keyword is a powerful way to describe your rule. It takes the format a cond b, where the values a and b are separated by cond, a condition. The condition can be any of these:
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rewrites the first local option with code 0xffee, setting the data to "abcd". Equivalent:
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~~~
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is = a equals b
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not = a does NOT equal b
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has = a has b as a substring (b is a substring of a)
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not_has = b is NOT a substring of a
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starts_with = b is a prefix of a
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ends_with = b is a suffix of a
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match = a matches b, where b is a regular expression
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not_match = a does NOT match b, where b is a regular expression
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rewrite edns0 local set 0xffee abcd
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~~~
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## Examples
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### `EDNS0_NSID`
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When requests come in for /mobile, actually serve /mobile/index.
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rewrite /mobile /mobile/index
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If the file is not favicon.ico and it is not a valid file or directory, serve the maintenance page if present, or finally, rewrite to index.php.
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~~~
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rewrite {
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if {file} not favicon.ico
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to {path} {path}/ /maintenance.html /index.php
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}
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~~~
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If user agent includes "mobile" and path is not a valid file/directory, rewrite to the mobile index page.
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~~~
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rewrite {
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if if {>User-agent} has mobile
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to {path} {path}/ /mobile/index.php
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}
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~~~
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If the request path starts with /source, respond with HTTP 403 Forbidden.
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~~~
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rewrite {
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regexp ^/source
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status 403
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}
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~~~
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Rewrite /app to /index with a query string. {1} is the matched group (.*).
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~~~
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rewrite /app {
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r (.*)
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to /index?path={1}
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}
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~~~
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This has no fields; it will add an NSID option with an empty string for the NSID. If the option already exists
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and the action is `replace` or `set`, then the NSID in the option will be set to the empty string.
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