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Hello flichtenheld,
I'd like you to do a code review.
Please visit
http://gerrit.openvpn.net/c/openvpn/+/803?usp=email
to review the following change.
Change subject: Add methods to read/write packet ids for epoch data
......................................................................
Add methods to read/write packet ids for epoch data
Change-Id: I2a104decdb1e77a460f7a6976bcd0560b67a07b5
Signed-off-by: Arne Schwabe <a...@rfc2549.org>
---
M src/openvpn/packet_id.c
M src/openvpn/packet_id.h
M tests/unit_tests/openvpn/test_packet_id.c
3 files changed, 137 insertions(+), 2 deletions(-)
git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/03/803/1
diff --git a/src/openvpn/packet_id.c b/src/openvpn/packet_id.c
index 117c95f..8cde108 100644
--- a/src/openvpn/packet_id.c
+++ b/src/openvpn/packet_id.c
@@ -343,6 +343,21 @@
return true;
}
+static bool
+packet_id_send_update_epoch(struct packet_id_send *p)
+{
+ if (!p->time)
+ {
+ p->time = now;
+ }
+ if (p->id == PACKET_ID_EPOCH_MAX)
+ {
+ return false;
+ }
+ p->id++;
+ return true;
+}
+
bool
packet_id_write(struct packet_id_send *p, struct buffer *buf, bool long_form,
bool prepend)
@@ -634,4 +649,46 @@
gc_free(&gc);
}
+uint16_t
+packet_id_read_epoch(struct packet_id_net *pin, struct buffer *buf)
+{
+ uint64_t packet_id;
+
+
+ if (!buf_read(buf, &packet_id, sizeof(packet_id)))
+ {
+ return 0;
+ }
+
+ uint64_t id = ntohll(packet_id);
+ /* top most 16 bits */
+ uint16_t epoch = id >> 48;
+
+ pin->id = id & 0xffffffffffffull;
+ return epoch;
+}
+
+bool
+packet_id_write_epoch(struct packet_id_send *p, uint16_t epoch, struct buffer
*buf)
+{
+ if (!packet_id_send_update_epoch(p))
+ {
+ return false;
+ }
+
+ /* First 16 bits of packet id is the epoch
+ *
+ * Next 48 bits are the per-epoch packet id counter. Since we are
+ * writing a big endian counter, the last 6 bytes of the 64 bit
+ * integer contain our counter but the upper two bytes are always 0 */
+
+ uint64_t net_id = ((uint64_t) epoch) << 48 | p->id;
+
+ /* convert to network order */
+ net_id = htonll(net_id);
+
+ return buf_write(buf, &net_id, sizeof(net_id));
+}
+
+
#endif /* ifdef ENABLE_DEBUG */
diff --git a/src/openvpn/packet_id.h b/src/openvpn/packet_id.h
index d8a3e1a..79224d2 100644
--- a/src/openvpn/packet_id.h
+++ b/src/openvpn/packet_id.h
@@ -44,7 +44,8 @@
* These are ephemeral and are never saved to a file.
*/
typedef uint32_t packet_id_type;
-#define PACKET_ID_MAX UINT32_MAX
+#define PACKET_ID_MAX UINT32_MAX
+#define PACKET_ID_EPOCH_MAX 0x0000ffffffffffffull
typedef uint32_t net_time_t;
/*
@@ -158,7 +159,8 @@
* includes a timestamp as well.
*
* An epoch packet-id is a 16 bit epoch
- * counter plus a 48 per-epoch packet-id
+ * counter plus a 48 per-epoch packet-id.
+ *
*
* Long packet-ids are used as IVs for
* CFB/OFB ciphers and for control channel
@@ -321,4 +323,25 @@
}
}
+/**
+ * Writes the packet ID containing both the epoch and the packet id to the
+ * buffer specified by buf.
+ * @param p packed id send structure to use for the packet id
+ * @param epoch epoch to write to the packet
+ * @param buf buffer to write the packet id/epcoh to
+ * @return false if the packet id space is exhausted and cannot be
written
+ */
+bool
+packet_id_write_epoch(struct packet_id_send *p, uint16_t epoch, struct buffer
*buf);
+
+/**
+ * Reads the packet ID containing both the epoch and the per-epoch counter
+ * from the buf. Will return 0 as epoch id if there is any error.
+ * @param p packet_id struct to popupulate with the on-wire counter
+ * @param buf buffer to read the packet id from.
+ * @return 0 for an error/invalid id, epoch otherwise
+ */
+uint16_t
+packet_id_read_epoch(struct packet_id_net *p, struct buffer *buf);
+
#endif /* PACKET_ID_H */
diff --git a/tests/unit_tests/openvpn/test_packet_id.c
b/tests/unit_tests/openvpn/test_packet_id.c
index d918985..a24580b 100644
--- a/tests/unit_tests/openvpn/test_packet_id.c
+++ b/tests/unit_tests/openvpn/test_packet_id.c
@@ -44,6 +44,7 @@
} test_buf_data;
struct buffer test_buf;
struct packet_id_send pis;
+ struct gc_arena gc;
};
static int
@@ -59,6 +60,7 @@
data->test_buf.data = (void *) &data->test_buf_data;
data->test_buf.capacity = sizeof(data->test_buf_data);
+ data->gc = gc_new();
*state = data;
return 0;
@@ -67,6 +69,8 @@
static int
test_packet_id_write_teardown(void **state)
{
+ struct test_packet_id_write_data *data = *state;
+ gc_free(&data->gc);
free(*state);
return 0;
}
@@ -209,6 +213,53 @@
reliable_free(rel);
}
+static void
+test_packet_id_write_epoch(void **state)
+{
+ struct test_packet_id_write_data *data = *state;
+
+ struct buffer buf = alloc_buf_gc(128, &data->gc);
+
+ /* test normal writing of packet id to the buffer */
+ assert_true(packet_id_write_epoch(&data->pis, 0x23, &buf));
+
+ assert_int_equal(buf.len, 8);
+ uint8_t expected_header[8] = { 0x00, 0x23, 0, 0, 0, 0, 0, 1};
+ assert_memory_equal(BPTR(&buf), expected_header, 8);
+
+ /* too small buffer should error out */
+ struct buffer buf_short = alloc_buf_gc(5, &data->gc);
+ assert_false(packet_id_write_epoch(&data->pis, 0xabde, &buf_short));
+
+ /* test a true 48 bit packet id */
+ data->pis.id = 0xfa079ab9d2e8;
+ struct buffer buf_48 = alloc_buf_gc(128, &data->gc);
+ assert_true(packet_id_write_epoch(&data->pis, 0xfffe, &buf_48));
+ uint8_t expected_header_48[8] = { 0xff, 0xfe, 0xfa, 0x07, 0x9a, 0xb9,
0xd2, 0xe9};
+ assert_memory_equal(BPTR(&buf_48), expected_header_48, 8);
+
+ /* test writing/checking the 48 bit overflow */
+ data->pis.id = 0xfffffffffffe;
+ struct buffer buf_of = alloc_buf_gc(128, &data->gc);
+ assert_true(packet_id_write_epoch(&data->pis, 0xf00f, &buf_of));
+ uint8_t expected_header_of[8] = { 0xf0, 0x0f, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff};
+ assert_memory_equal(BPTR(&buf_of), expected_header_of, 8);
+
+ /* This is go over 2^48 - 1 and should error out. */
+ assert_false(packet_id_write_epoch(&data->pis, 0xf00f, &buf_of));
+
+ /* Now read back the packet ids and check if they are the same as what we
+ * have written */
+ struct packet_id_net pin;
+ assert_int_equal(packet_id_read_epoch(&pin, &buf), 0x23);
+ assert_int_equal(pin.id, 1);
+
+ assert_int_equal(packet_id_read_epoch(&pin, &buf_48), 0xfffe);
+ assert_int_equal(pin.id, 0xfa079ab9d2e9);
+
+ assert_int_equal(packet_id_read_epoch(&pin, &buf_of), 0xf00f);
+ assert_int_equal(pin.id, 0xffffffffffff);
+}
static void
test_copy_acks_to_lru(void **state)
@@ -296,6 +347,10 @@
cmocka_unit_test_setup_teardown(test_packet_id_write_long_wrap,
test_packet_id_write_setup,
test_packet_id_write_teardown),
+ cmocka_unit_test_setup_teardown(test_packet_id_write_epoch,
+ test_packet_id_write_setup,
+ test_packet_id_write_teardown),
+
cmocka_unit_test(test_get_num_output_sequenced_available),
cmocka_unit_test(test_copy_acks_to_lru)
--
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Gerrit-Project: openvpn
Gerrit-Branch: master
Gerrit-Change-Id: I2a104decdb1e77a460f7a6976bcd0560b67a07b5
Gerrit-Change-Number: 803
Gerrit-PatchSet: 1
Gerrit-Owner: plaisthos <arne-open...@rfc2549.org>
Gerrit-Reviewer: flichtenheld <fr...@lichtenheld.com>
Gerrit-CC: openvpn-devel <openvpn-devel@lists.sourceforge.net>
Gerrit-Attention: flichtenheld <fr...@lichtenheld.com>
Gerrit-MessageType: newchange
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