Add TKL IDs via message tags in S2S.

By default - assuming you don't set set::reject-message things by yourself -
the *LINE id is appended at the end of the rejection that is shown to the
user, like: [ID: G7K2MP9WQX3].

Also new is spamfilter to *LINE mapping, so you can see which *LINE was
set by which SPAMFILTER. For this STATS gline and friends were enhanced.
In fact, multiple fields were added there, including some that are 0
(zero) placeholders at the moment. These will be set in a future commit.
Some things were combined here so we only have to break STATS and tkldb
database format once (unless i made a mistake, then the follow up commit
will correct that i guess :D).

This was requested by Hero in https://bugs.unrealircd.org/view.php?id=4397
in 2015. Again by musk in https://bugs.unrealircd.org/view.php?id=4397
in 2022. And on IRC by Chris and others.

As you can see it was not SUPER easy and a lot of thought went into this
(and in terms of S2S traffic it is part of something bigger too)

include/h.h

@@ -953,7 +953,7 @@ extern MODVAR int (*decode_authenticate_plain)(const char *param, char **authori
 extern MODVAR void (*exit_client)(Client *client, MessageTag *recv_mtags, const char *comment);
 extern MODVAR void (*exit_client_fmt)(Client *client, MessageTag *recv_mtags, FORMAT_STRING(const char *pattern), ...) __attribute__((format(printf, 3, 4)));
 extern MODVAR void (*exit_client_ex)(Client *client, Client *origin, MessageTag *recv_mtags, const char *comment);
-extern MODVAR void (*banned_client)(Client *client, const char *bantype, const char *reason, int global, int noexit);
+extern MODVAR void (*banned_client)(Client *client, const char *bantype, const char *reason, const char *tklid, int global, int noexit);
 extern MODVAR char *(*unreal_expand_string)(const char *str, char *buf, size_t buflen, NameValuePrioList *nvp, int buildvarstring_options, Client *client);
 extern MODVAR char *(*utf8_convert_confusables)(const char *i, char *obuf, int olen);
 extern MODVAR const char *(*utf8_get_block_name)(int i);

include/numeric.h

@@ -372,17 +372,17 @@
 #define STR_RPL_STATSCOMMANDS		/* 212 */	"%s %u %lu"
 #define STR_RPL_STATSCLINE		/* 213 */	"%c %s * %s %d %d %s"
 #define STR_RPL_STATSILINE		/* 215 */	"I %s %s %d %d %s %s %d"
-#define STR_RPL_STATSQLINE		/* 217 */	"%c %s %lld %lld %s :%s"
+#define STR_RPL_STATSQLINE		/* 217 */	"%c %s %lld %lld %s %lld %lld %s :%s"
 #define STR_RPL_STATSYLINE		/* 218 */	"Y %s %d %d %d %d %d"
 #define STR_RPL_ENDOFSTATS		/* 219 */	"%c :End of /STATS report"
 #define STR_RPL_UMODEIS			/* 221 */	"%s"
-#define STR_RPL_STATSGLINE		/* 223 */	"%c %s %lld %lld %s :%s"
+#define STR_RPL_STATSGLINE		/* 223 */	"%c %s %lld %lld %s %lld %lld %s %s :%s"
 #define STR_RPL_STATSTLINE		/* 224 */	"T %s %s %s"
 #define STR_RPL_STATSNLINE		/* 226 */	"n %s %s"
 #define STR_RPL_STATSVLINE		/* 227 */	"v %s %s %s"
 #define STR_RPL_STATSBANVER		/* 228 */	"%s %s"
-#define STR_RPL_STATSSPAMF		/* 229 */	"%c %s %s %s %lld %lld %lld %s %s %lld %lld :%s"
-#define STR_RPL_STATSEXCEPTTKL		/* 230 */	"%s %s %lld %lld %s :%s"
+#define STR_RPL_STATSSPAMF		/* 229 */	"%c %s %s %s %lld %lld %lld %s %s %lld %lld %lld %lld %s :%s"
+#define STR_RPL_STATSEXCEPTTKL		/* 230 */	"%s %s %lld %lld %s %s :%s"
 #define STR_RPL_RULES			/* 232 */	":- %s"
 #define STR_RPL_STATSLLINE		/* 241 */	"%c %s * %s %d %d"
 #define STR_RPL_STATSUPTIME		/* 242 */	":Server Up %lld days, %lld:%02lld:%02lld"

include/struct.h

@@ -204,7 +204,6 @@ typedef OperPermission (*OperClassEntryEvalCallback)(OperClassACLEntryVar* varia
 #define MAXCCUSERS		20 /* Maximum for set::anti-flood::max-concurrent-conversations */
 #define BATCHLEN	22
 #define MAXBATCHREFLEN	48	/* Max length of client-sent batch reference tags */
-#define MAXSPAMFILTERIDLEN	24
 
 /*
  * Watch it - Don't change this unless you also change the ERR_TOOMANYWATCH
@@ -1319,6 +1318,8 @@ struct BanException {
 #define TKL_FLAG_CONFIG			0x0001 /* Entry from configuration file. Cannot be removed by using commands. */
 #define TKL_FLAG_CENTRAL_SPAMFILTER	0x0002 /* Entry from central spamfilter. */
 
+#define TKLIDLEN			16 /**< TKL id buffer size: native 'prefix+body' or an external id. Max 15 chars + NUL. */
+
 /** A TKL entry, such as a KLINE, GLINE, Spamfilter, QLINE, Exception, .. */
 struct TKL {
 	TKL *prev, *next;
@@ -1327,6 +1328,8 @@ struct TKL {
 	char *set_by; /**< By who was this entry added */
 	time_t set_at; /**< When this entry was added */
 	time_t expire_at; /**< When this entry will expire */
+	char id[TKLIDLEN]; /**< Unique ID: assigned (random, generated by originating server) or external (eg from services), or empty string if none */
+	char spamfilter_id[TKLIDLEN]; /**< For server bans created by a spamfilter: that spamfilter's id. Empty otherwise. */
 	union {
 		Spamfilter *spamfilter;
 		ServerBan *serverban;