From: martijn <martijn@openbsd.org>
Date: Fri, 5 Feb 2021 10:30:45 +0000 (+0000)
Subject: Introduce a transaction id. This is currently mostly a dummy-variable, but
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=2df89b5475f99a34c3dfc47781f199ae5f772345;p=openbsd

Introduce a transaction id. This is currently mostly a dummy-variable, but
will later on be needed for when we reintroduce agentx master support.

feedback and OK dlg@, rob@
---

diff --git a/usr.sbin/snmpd/snmpd.h b/usr.sbin/snmpd/snmpd.h
index c490ed2fd46..40f08748d4b 100644
--- a/usr.sbin/snmpd/snmpd.h
+++ b/usr.sbin/snmpd/snmpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmpd.h,v 1.93 2021/01/28 20:45:14 martijn Exp $	*/
+/*	$OpenBSD: snmpd.h,v 1.94 2021/02/05 10:30:45 martijn Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008, 2012 Reyk Floeter <reyk@openbsd.org>
@@ -399,6 +399,8 @@ struct snmp_message {
 	u_int8_t		 sm_data[READ_BUF_SIZE];
 	size_t			 sm_datalen;
 
+	uint32_t		 sm_transactionid;
+
 	u_int			 sm_version;
 
 	/* V1, V2c */
@@ -436,7 +438,11 @@ struct snmp_message {
 
 	struct ber_element	*sm_varbind;
 	struct ber_element	*sm_varbindresp;
+
+	RB_ENTRY(snmp_message)	 sm_entry;
 };
+RB_HEAD(snmp_messages, snmp_message);
+extern struct snmp_messages snmp_messages;
 
 /* Defined in SNMPv2-MIB.txt (RFC 3418) */
 struct snmp_stats {
@@ -642,6 +648,8 @@ struct kif_arp	*karp_getaddr(struct sockaddr *, u_short, int);
 void		 snmpe(struct privsep *, struct privsep_proc *);
 void		 snmpe_shutdown(void);
 void		 snmpe_dispatchmsg(struct snmp_message *);
+int		 snmp_messagecmp(struct snmp_message *, struct snmp_message *);
+RB_PROTOTYPE(snmp_messages, snmp_message, sm_entry, snmp_messagecmp)
 
 /* trap.c */
 void		 trap_init(void);
diff --git a/usr.sbin/snmpd/snmpe.c b/usr.sbin/snmpd/snmpe.c
index 4aea2d5c2b1..9d063206854 100644
--- a/usr.sbin/snmpd/snmpe.c
+++ b/usr.sbin/snmpd/snmpe.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmpe.c,v 1.68 2021/01/22 06:33:27 martijn Exp $	*/
+/*	$OpenBSD: snmpe.c,v 1.69 2021/02/05 10:30:45 martijn Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008, 2012 Reyk Floeter <reyk@openbsd.org>
@@ -58,6 +58,8 @@ void	 snmp_msgfree(struct snmp_message *);
 struct imsgev	*iev_parent;
 static const struct timeval	snmpe_tcp_timeout = { 10, 0 }; /* 10s */
 
+struct snmp_messages snmp_messages = RB_INITIALIZER(&snmp_messages);
+
 static struct privsep_proc procs[] = {
 	{ "parent",	PROC_PARENT }
 };
@@ -210,6 +212,11 @@ snmpe_parse(struct snmp_message *msg)
 
 	msg->sm_errstr = "invalid message";
 
+	do {
+		msg->sm_transactionid = arc4random();
+	} while (msg->sm_transactionid == 0 ||
+	    RB_INSERT(snmp_messages, &snmp_messages, msg) != NULL);
+
 	if (ober_scanf_elements(root, "{ie", &ver, &a) != 0)
 		goto parsefail;
 
@@ -834,6 +841,8 @@ snmpe_response(struct snmp_message *msg)
 void
 snmp_msgfree(struct snmp_message *msg)
 {
+	if (msg->sm_transactionid != 0)
+		RB_REMOVE(snmp_messages, &snmp_messages, msg);
 	event_del(&msg->sm_sockev);
 	ober_free(&msg->sm_ber);
 	if (msg->sm_req != NULL)
@@ -896,3 +905,12 @@ snmpe_encode(struct snmp_message *msg)
 #endif
 	return 0;
 }
+
+int
+snmp_messagecmp(struct snmp_message *m1, struct snmp_message *m2)
+{
+	return (m1->sm_transactionid < m2->sm_transactionid ? -1 :
+	    m1->sm_transactionid > m2->sm_transactionid);
+}
+
+RB_GENERATE(snmp_messages, snmp_message, sm_entry, snmp_messagecmp)