[WIP] Fix ban by software version, some other under-hood changes

- Use updated version of upstream go-xmpp + fixes on client-side
- Introduce golangci-lint v2 + fixes
- Move especially noisy debugging stuff to separate config handles to be able to switch them off
- Add a bit debug to ban by software path

vendor/github.com/xmppo/go-xmpp/xmpp_information_query.go

@@ -0,0 +1,97 @@
+package xmpp
+
+import (
+	"fmt"
+	"time"
+)
+
+func (c *Client) Discovery() (string, error) {
+	// use UUIDv4 for a pseudo random id.
+	reqID := getUUID()
+	return c.RawInformationQuery(c.jid, c.domain, reqID, IQTypeGet, XMPPNS_DISCO_ITEMS, "")
+}
+
+// Discover information about a node. Empty node queries info about server itself.
+func (c *Client) DiscoverNodeInfo(node string) (string, error) {
+	query := fmt.Sprintf("<query xmlns='%s' node='%s'/>", XMPPNS_DISCO_INFO, node)
+	return c.RawInformation(c.jid, c.domain, getUUID(), IQTypeGet, query)
+}
+
+// Discover information about given item from given jid.
+func (c *Client) DiscoverInfo(to string) (string, error) {
+	query := fmt.Sprintf("<query xmlns='%s'/>", XMPPNS_DISCO_INFO)
+	return c.RawInformation(c.jid, to, getUUID(), IQTypeGet, query)
+}
+
+// Discover items that the server exposes
+func (c *Client) DiscoverServerItems() (string, error) {
+	return c.DiscoverEntityItems(c.domain)
+}
+
+// Discover items that an entity exposes
+func (c *Client) DiscoverEntityItems(jid string) (string, error) {
+	query := fmt.Sprintf("<query xmlns='%s'/>", XMPPNS_DISCO_ITEMS)
+	return c.RawInformation(c.jid, jid, getUUID(), IQTypeGet, query)
+}
+
+// RawInformationQuery sends an information query request to the server.
+func (c *Client) RawInformationQuery(from, to, id, iqType, requestNamespace, body string) (string, error) {
+	const xmlIQ = "<iq from='%s' to='%s' id='%s' type='%s'><query xmlns='%s'>%s</query></iq>\n"
+	_, err := fmt.Fprintf(c.stanzaWriter, xmlIQ, xmlEscape(from), xmlEscape(to), id, iqType, requestNamespace, body)
+	return id, err
+}
+
+// rawInformation send a IQ request with the payload body to the server
+func (c *Client) RawInformation(from, to, id, iqType, body string) (string, error) {
+	const xmlIQ = "<iq from='%s' to='%s' id='%s' type='%s'>%s</iq>\n"
+	_, err := fmt.Fprintf(c.stanzaWriter, xmlIQ, xmlEscape(from), xmlEscape(to), id, iqType, body)
+	return id, err
+}
+
+// UrnXMPPTimeResponse implements response to query entity's current time (xep-0202).
+func (c *Client) UrnXMPPTimeResponse(v IQ, timezoneOffset string) (string, error) {
+	query := fmt.Sprintf(
+		"<time xmlns=\"%s\"><tzo>%s</tzo><utc>%s</utc></time>",
+		XMPPNS_TIME,
+		timezoneOffset,
+		time.Now().UTC().Format(time.RFC3339),
+	)
+
+	return c.RawInformation(
+		v.To,
+		v.From,
+		v.ID,
+		IQTypeResult,
+		query,
+	)
+}
+
+// IqVersionResponse responding with software version, according to xep-0092.
+func (c *Client) IqVersionResponse(v IQ, name string, version string, os string) (string, error) {
+	if name == "" {
+		name = "go-xmpp"
+		version = Version
+	}
+
+	if version == "" {
+		version = "undefined"
+	}
+
+	query := fmt.Sprintf("<query xmlns=\"%s\">", XMPPNS_IQ_VERSION)
+	query += fmt.Sprintf("<name>%s</name>", name)
+	query += fmt.Sprintf("<version>%s</version>", version)
+
+	if os != "" {
+		query += fmt.Sprintf("<os>%s</os>", os)
+	}
+
+	query += "</query>"
+
+	return c.RawInformation(
+		v.To,
+		v.From,
+		v.ID,
+		IQTypeResult,
+		query,
+	)
+}