modules: Minor protocol and module enhancements.

* mod_http: Recognize Max-Forwards header. This is not currently used
  for anything, but could be in the future.
* mod_http_proxy: Improve /0 CIDR range detection for warning.
* mod_smtp_delivery_external: Include SMTP response in SMTP logs, so
  we can later see exactly why delivery of a message failed.
* mod_smtp_delivery_external: Remove year from mailq printouts. Messages
  are never retried for more than a year, so including the year in the
  timestamps just takes up space unnecessarily.

include/mod_http.h

@@ -117,6 +117,7 @@ struct http_request {
 	unsigned int expect100:1;	/*!< Expecting 100-continue */
 	unsigned int parsedbody:1;
 	unsigned int absolute:1;	/*!< Absolute host used in request */
+	unsigned int noforward:1;	/*!< Don't forward request further (i.e. Max-Forwards: 0) */
 };
 
 struct http_response {

modules/mod_http.c

@@ -1819,6 +1819,36 @@ static int http_handle_request(struct http_session *http, char *buf)
 		return res;
 	}
 
+	/* RFC 9110 7.6.2
+	 * For OPTIONS and TRACE requests, if a Max-Forwards header is provided,
+	 * we MUST NOT forward the request if its value is 0,
+	 * and MUST decrement it otherwise (or set it to the local max supported Max-Forwards)
+	 * We MAY ignore Max-Forwards for other methods, but don't have to, either...
+	 * Currently, we don't forward requests (outside of the CONNECT proxy support),
+	 * but we handle this anyways. */
+	if (http->req->method & (HTTP_METHOD_OPTIONS | HTTP_METHOD_TRACE)) {
+		const char *maxforwards = http_request_header(http, "Max-Forwards");
+		if (!strlen_zero(maxforwards)) {
+			int maxfwds = atoi(maxforwards);
+			if (maxfwds) {
+				char newmaxforwards[16];
+				snprintf(newmaxforwards, sizeof(newmaxforwards), "%d", --maxfwds);
+				/* BUGBUG This will only work if the case matches (e.g. request received
+				 * was case-sensitively 'Max-Forwards'. If not, we will end up creating
+				 * a new header with the canonical casing, and leave the old one intact... ouch.
+				 * Leaving this unfixed for now, but it forwarding is ever added and this matters,
+				 * we will need to be able to update headers case-insensitively, to be compatible
+				 * with modifying existing headers as received. */
+				http_set_header(http, "Max-Forwards", newmaxforwards);
+			} else {
+				/* Currently, there is nothing that checks this,
+				 * but if OPTIONS and TRACE were to be implemented and in a way that supported forwarding,
+				 * they would need to obey this. */
+				http->req->noforward = 1;
+			}
+		}
+	}
+
 	/* Proxy requests really need to be handled before doing anything else, since they're fairly low level.
 	 * We don't want to read or process the body.
 	 * We don't care what the request is for,

modules/mod_http_proxy.c

@@ -48,7 +48,7 @@ static void add_proxy_client(const char *source, const char *domains)
 {
 	struct http_proxy_client *c;
 
-	if (STARTS_WITH(source, "0.0.0.0")) {
+	if (STARTS_WITH(source, "0.0.0.0") || strstr(source, "/0")) {
 		/* If someone wants to shoot him/herself in the foot, at least provide a warning */
 		bbs_notice("This server is configured as an open proxy and may be abused!\n");
 	}

modules/mod_smtp_delivery_external.c

@@ -1180,7 +1180,7 @@ static int process_queue_file(struct mailq_run *qrun, struct mailq_file *mqf)
 	if (!res) {
 		/* Successful delivery. */
 		bbs_debug(6, "Delivery successful after %d attempt%s, discarding queue file\n", mqf->newretries, ESS(mqf->newretries));
-		bbs_smtp_log(4, NULL, "Delivery succeeded after queuing: %s -> %s\n", mqf->realfrom, mqf->realto);
+		bbs_smtp_log(4, NULL, "Delivery succeeded after queuing: %s -> %s (%s)\n", mqf->realfrom, mqf->realto, buf);
 		smtp_trigger_dsn(DELIVERY_DELIVERED, &tx, &mqf->created, mqf->realfrom, mqf->realto, buf, fileno(mqf->fp), mqf->metalen, mqf->size - mqf->metalen);
 		fclose(mqf->fp);
 		mqf->fp = NULL; /* For parallel task framework, since cleanup is always called */
@@ -1193,7 +1193,7 @@ static int process_queue_file(struct mailq_run *qrun, struct mailq_file *mqf)
 	if (res == -2 || res > 0 || mqf->newretries >= (int) max_retries) {
 		/* Send a delivery failure response, then delete the file. */
 		bbs_warning("Delivery of message %s from %s to %s has failed permanently after %d retries\n", mqf->fullname, mqf->realfrom, mqf->realto, mqf->newretries);
-		bbs_smtp_log(1, NULL, "Delivery failed permanently after queuing: %s -> %s\n", mqf->realfrom, mqf->realto);
+		bbs_smtp_log(1, NULL, "Delivery failed permanently after queuing: %s -> %s (%s)\n", mqf->realfrom, mqf->realto, buf);
 		/* To the dead letter office we go */
 		/* XXX buf will only contain the last line of the SMTP transaction, since it was using the readline buffer
 		 * Thus, if we got a multiline error, only the last line is currently included in the non-delivery report */
@@ -1204,7 +1204,7 @@ static int process_queue_file(struct mailq_run *qrun, struct mailq_file *mqf)
 		QUEUE_INCR_STAT(failed);
 		return 0;
 	} else {
-		bbs_smtp_log(3, NULL, "Delivery delayed after queuing: %s -> %s\n", mqf->realfrom, mqf->realto);
+		bbs_smtp_log(3, NULL, "Delivery delayed after queuing: %s -> %s (%s)\n", mqf->realfrom, mqf->realto, buf);
 		mailq_file_punt(mqf); /* Try again later */
 		smtp_trigger_dsn(DELIVERY_DELAYED, &tx, &mqf->created, mqf->realfrom, mqf->realto, buf, fileno(mqf->fp), mqf->metalen, mqf->size - mqf->metalen);
 		QUEUE_INCR_STAT(delayed);
@@ -1517,8 +1517,8 @@ static int on_queue_file_cli_mailq(const char *dir_name, const char *filename, v
 		return 0;
 	}
 
-	strftime(arrival_date, sizeof(arrival_date), "%a, %d %b %Y %H:%M:%S", &mqf->created);
-	strftime(retry_date, sizeof(retry_date), "%a, %d %b %Y %H:%M:%S", &mqf->retried);
+	strftime(arrival_date, sizeof(arrival_date), "%a, %d %b %H:%M:%S", &mqf->created);
+	strftime(retry_date, sizeof(retry_date), "%a, %d %b %H:%M:%S", &mqf->retried);
 
 	/* For user convenience, try to calculate when message delivery will be attempted next. */
 	next_retry_time = mqf->retriedtime + queue_retry_threshold(mqf->retries); /* Minimum time that it would get processed */
@@ -1546,11 +1546,11 @@ static int on_queue_file_cli_mailq(const char *dir_name, const char *filename, v
 	}
 
 	localtime_r(&next_retry_time, &est_retry);
-	strftime(next_retry_date, sizeof(next_retry_date), "%a, %d %b %Y %H:%M:%S", &est_retry);
+	strftime(next_retry_date, sizeof(next_retry_date), "%a, %d %b %H:%M:%S", &est_retry);
 
 	/* Ensure the format is synchronized with the heading in cli_mailq */
 	/* Printing mqf->retries this way is already 1-indexed as well. */
-	bbs_dprintf(qrun->clifd, "%7d %-25s %-25s %-25s %-20s %5ld %-35s %s\n",
+	bbs_dprintf(qrun->clifd, "%7d %-21s %-21s %-21s %-20s %5ld %-35s %s\n",
 		mqf->retries, arrival_date, retry_date, next_retry_date, filename,
 		(mqf->size + 1023) / 1024, /* Display size in KB, rounded up to the nearest KB */
 		mqf->realfrom, mqf->realto);
@@ -1569,7 +1569,7 @@ static int cli_mailq(struct bbs_cli_args *a)
 		qrun.host_ends_with = a->argv[1];
 	}
 
-	bbs_dprintf(a->fdout, "%7s %-25s %-25s %-25s %-20s %5s %-35s %s\n", "Retries", "Orig Date", "Last Retry", "Est. Next Retry", "Filename", "Size", "Sender", "Recipient");
+	bbs_dprintf(a->fdout, "%7s %-21s %-21s %-21s %-20s %5s %-35s %s\n", "Retries", "Orig Date", "Last Retry", "Est. Next Retry", "Filename", "Size", "Sender", "Recipient");
 	run_queue(&qrun, on_queue_file_cli_mailq);
 	bbs_dprintf(a->fdout, "%d message%s currently in mail queue\n", qrun.total, ESS(qrun.total));
 	mailq_run_cleanup(&qrun);

nets/net_smtp.c

@@ -858,6 +858,7 @@ static int parse_mail_parameters(struct smtp_session *smtp, char *s)
 			 * In my experience, most mail that requires 8BITMIME is spam.
 			 * But it's probably not our place to reject such mail. */
 			if (!strcasecmp(d, "8BITMIME")) {
+				bbs_debug(3, "Sender indicated this is an 8-bit message... increasing spam score\n");
 				smtp->tflags.is8bit = 1;
 				smtp->failures++; /* Penalize 8-bit messages. These are probably spam. */
 			} else if (!strcasecmp(d, "7BIT")) {