From: Alan T. DeKok <aland@freeradius.org>
Date: Tue, 21 Jul 2020 02:21:05 +0000 (-0400)
Subject: add tracking table for DHCPv6
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=32755a6ed91729a73300a577a7f95aeb4664b9f6;p=thirdparty%2Ffreeradius-server.git

add tracking table for DHCPv6

by packet code, transaction ID, and (if available) client id

note that we don't care what the client ID is, we just compare
it as an opaque binary blob.  Which isn't perfect, but should be
good enough for our intents and purposes
---

diff --git a/src/modules/proto_dhcpv6/proto_dhcpv6.h b/src/modules/proto_dhcpv6/proto_dhcpv6.h
index f9c612cb8e9..615180fa834 100644
--- a/src/modules/proto_dhcpv6/proto_dhcpv6.h
+++ b/src/modules/proto_dhcpv6/proto_dhcpv6.h
@@ -47,3 +47,12 @@ typedef struct {
  *	No one outside of proto_dhcpv6 needs this definition.
  */
 #define FR_DHCPV6_DO_NOT_RESPOND (256)
+
+/*
+ *	Shorter version of the packet for deduping
+ */
+typedef struct {
+	uint32_t			header;
+	size_t				client_id_len;
+	uint8_t				client_id[0];
+} proto_dhcpv6_track_t;
diff --git a/src/modules/proto_dhcpv6/proto_dhcpv6_udp.c b/src/modules/proto_dhcpv6/proto_dhcpv6_udp.c
index 9fdc9b4cac4..b6678b71374 100644
--- a/src/modules/proto_dhcpv6/proto_dhcpv6_udp.c
+++ b/src/modules/proto_dhcpv6/proto_dhcpv6_udp.c
@@ -120,10 +120,12 @@ fr_dict_autoload_t proto_dhcpv6_udp_dict[] = {
 };
 
 static fr_dict_attr_t const *attr_packet_type;
+static fr_dict_attr_t const *attr_client_id;
 
 extern fr_dict_attr_autoload_t proto_dhcpv6_udp_dict_attr[];
 fr_dict_attr_autoload_t proto_dhcpv6_udp_dict_attr[] = {
 	{ .out = &attr_packet_type, .name = "Packet-Type", .type = FR_TYPE_UINT32, .dict = &dict_dhcpv6},
+	{ .out = &attr_client_id, .name = "Client-ID", .type = FR_TYPE_STRUCT, .dict = &dict_dhcpv6},
 	{ NULL }
 };
 
@@ -385,6 +387,49 @@ static int mod_fd_set(fr_listen_t *li, int fd)
 	return 0;
 }
 
+static void *mod_track_create(TALLOC_CTX *ctx, uint8_t const *packet, size_t packet_len)
+{
+	proto_dhcpv6_track_t *track;
+	uint8_t const *option;
+	size_t track_size = sizeof(*track);
+	size_t option_len = 0;
+	
+	option = fr_dhcpv6_option_find(packet, packet + packet_len, attr_client_id->attr);
+	if (option) {
+		option_len = (option[2] << 8) | option[3];
+	}
+
+	track = (proto_dhcpv6_track_t *) talloc_zero_array(ctx, uint8_t, track_size + option_len);
+	if (!track) return NULL;
+
+	talloc_set_name_const(track, "proto_dhcpv4_track_t");
+
+	memcpy(&track->header, packet, 4); /* packet code + 24-bit transaction ID */
+	if (!option) return track;
+
+	memcpy(&track->client_id[0], option + 4, option_len);
+	track->client_id_len = option_len;
+
+	return track;
+}
+
+
+static int mod_compare(UNUSED void const *instance, UNUSED void *thread_instance, UNUSED RADCLIENT *client,
+		       void const *one, void const *two)
+{
+	int rcode;
+	proto_dhcpv6_track_t const *a = one;
+	proto_dhcpv6_track_t const *b = two;
+
+	rcode = memcmp(&a->header, &b->header, sizeof(a->header));
+	if (rcode != 0) return rcode;
+
+	rcode = (a->client_id_len < b->client_id_len) - (a->client_id_len > b->client_id_len);
+	if (rcode != 0) return rcode;
+
+	return memcmp(a->client_id, b->client_id, a->client_id_len);
+}
+
 
 static char const *mod_name(fr_listen_t *li)
 {
@@ -595,11 +640,14 @@ fr_app_io_t proto_dhcpv6_udp = {
 	.bootstrap		= mod_bootstrap,
 
 	.default_message_size	= 4096,
+	.track_duplicates	= true,
 
 	.open			= mod_open,
 	.read			= mod_read,
 	.write			= mod_write,
 	.fd_set			= mod_fd_set,
+	.track			= mod_track_create,
+	.compare		= mod_compare,
 	.connection_set		= mod_connection_set,
 	.network_get		= mod_network_get,
 	.client_find		= mod_client_find,