add an example spamfilter configuration file (probably shouldn't be used on actual networks of course)

doc/Makefile.am

@@ -8,7 +8,7 @@ localstatedir	= @localstatedir@
 
 # Local to the etc Makefile
 
-CONFS		= ircd.conf.example reference.conf
+CONFS		= ircd.conf.example reference.conf spamfilter.conf.example
 
 install-mkdirs:
 	-@if test ! -d $(DESTDIR)$(sysconfdir); then \

doc/spamfilter.conf.example

@@ -0,0 +1,96 @@
+/*
+ * charybdis: an advanced ircd.
+ * spamfilter.conf.example: An example extensions/spamfilter configuration
+ *
+ * Copyright (C) 2016 Jason Volk <jason@zemos.net>
+ */
+
+loadmodule "extensions/spamfilter";
+loadmodule "extensions/spamfilter_nicks";
+loadmodule "extensions/spamfilter_expr";
+
+/* The spamfiler block contains general configuration lines for spamfilter.so,
+ */
+spamfilter {
+	/* This message is sent when any spam filter is triggered. The variables ${network-name}
+	 * and ${admin-email} are substituted for your configured values. */
+	reject_reason = "Spam is off-topic on ${network-name}. If this is an error, please contact ${admin-email}";
+
+};
+
+
+/* The spamfiler_expr block contains general configuration for spamfilter_expr.so
+ * Note: If you change these settings and rehash, they may not be applied to existing
+ * expressions. You may have to reload the module.
+ */
+spamfilter_expr {
+	/* Maximum number of regular expressions allowed */
+	limit = 1024;
+
+	/* List of PCRE2 compile options added by default to all expressions.
+	 * See PCRE2_COMPILE(3) for a complete list. You omit the PCRE2_ prefix for this list. */
+	compile_opts = caseless;
+
+	/* List of PCRE2 match (execution) options added by default to all expressions.
+	 * See PCRE2_MATCH(3) for a complete list. You omit the PCRE2_ prefix for this list. */
+	match_opts = noteol, notbol;
+
+	/* List of PCRE2 JIT options added by default to all expressions.
+	 * See PCRE2JIT(3) and PCRE2API(3) for details.
+	 * You omit the PCRE2_JIT_ prefix for this list. */
+	jit_opts = complete;
+
+	/*
+	 * You ought to know what you're doing with these.
+	 */
+
+	match_limit = 512;
+	recursion_limit = 512;
+	parens_nest_limit = 32;
+
+	/* The starting size of the allocated JIT stack. */
+	jit_stack_size = 262144;
+
+	/* The maximum size of the allocated JIT stack.
+	 * (This may take precedence over previous options as the limiting recursion factor) */
+	jit_stack_max_size = 393216;
+};
+
+/* spamexpr blocks allow expressions to be configured offline.
+ * There may be multiple spamexpr blocks, each must have a pattern.
+ */
+spamexpr {
+	/* The regular expression pattern string. You will have to double-escape
+	 * any backslash to have a single backslash in the expression, thus triple-escape
+	 * any backslash to have an escape in the expression string itself! */
+	pattern = "foobar.+\\s";
+
+	/* Compile options specific to this pattern. This is or'ed with the compile_opts
+	 * specified in the general spamfilter_expr block. The rules are the same. */
+	compile_opts = caseless;
+};
+
+spamexpr {
+	pattern = "foo.*bar";
+};
+
+
+/*
+ * The spamfiler_nicks block contains general configuration for spamfilter_nicks.so
+ */
+spamfilter_nicks {
+	/* Number of nicknames in a message to trigger the nickspam filter. */
+	limit = 5;
+
+	/* Minimum length of a word considered a nickname candidate. */
+	nicklen_min = 4;
+
+	/* Size in bytes for the nickname bloom filter. */
+	bloom_size = 65536;
+
+	/* Number of hashing bits for the bloom filter (try log2 of the bloom_size unless you know better). */
+	bloom_bits = 16;
+
+	/* Time interval for when the bloom filter is flushed to prevent false positives. */
+	bloom_refresh = 5 minutes;
+};