eve/alert: enrich decoder event

Default decoder event alert was very sparse, not even logging packet
type and pcap_cnt. Expand support for this record type. It will be more
useful with the ethernet headers and packet field, but these are still
disabled by default.

Ticket: OISF#7433.
(cherry picked from commit 2fe2cf8)

src/output-json-alert.c

@@ -939,28 +939,40 @@ static int AlertJson(ThreadVars *tv, JsonAlertLogThread *aft, const Packet *p)
 static int AlertJsonDecoderEvent(ThreadVars *tv, JsonAlertLogThread *aft, const Packet *p)
 {
     AlertJsonOutputCtx *json_output_ctx = aft->json_output_ctx;
-    char timebuf[64];
 
     if (p->alerts.cnt == 0)
         return TM_ECODE_OK;
 
-    CreateIsoTimeString(p->ts, timebuf, sizeof(timebuf));
-
     for (int i = 0; i < p->alerts.cnt; i++) {
         const PacketAlert *pa = &p->alerts.alerts[i];
         if (unlikely(pa->s == NULL)) {
             continue;
         }
 
-        JsonBuilder *jb = jb_new_object();
-        if (unlikely(jb == NULL)) {
+        JsonBuilder *jb =
+                CreateEveHeader(p, LOG_DIR_PACKET, "alert", NULL, json_output_ctx->eve_ctx);
+        if (unlikely(jb == NULL))
             return TM_ECODE_OK;
+
+        AlertJsonHeader(json_output_ctx, p, pa, jb, json_output_ctx->flags, NULL, NULL);
+
+        if (IS_TUNNEL_PKT(p)) {
+            AlertJsonTunnel(p, jb);
         }
 
-        /* just the timestamp, no tuple */
-        jb_set_string(jb, "timestamp", timebuf);
+        /* base64-encoded full packet */
+        if (json_output_ctx->flags & LOG_JSON_PACKET) {
+            EvePacket(p, jb, 0);
+        }
 
-        AlertJsonHeader(json_output_ctx, p, pa, jb, json_output_ctx->flags, NULL, NULL);
+        char *pcap_filename = PcapLogGetFilename();
+        if (pcap_filename != NULL) {
+            jb_set_string(jb, "capture_file", pcap_filename);
+        }
+
+        if (json_output_ctx->flags & LOG_JSON_VERDICT) {
+            EveAddVerdict(jb, p);
+        }
 
         OutputJsonBuilderBuffer(jb, aft->ctx);
         jb_free(jb);