From b4babf0bdfec0bb787c92115caa183236cbcc9a5 Mon Sep 17 00:00:00 2001
From: huitema <huitema@huitema.net>
Date: Sat, 1 Dec 2018 19:13:20 -0800
Subject: [PATCH] Implement padding policy support
---
picoquic/picoquic.h | 5 +++
picoquic/picoquic_internal.h | 7 +++-
picoquic/quicctx.c | 24 +++++++++++++
picoquic/sender.c | 69 ++++++++++++++++++++++++++----------
4 files changed, 85 insertions(+), 20 deletions(-)
diff --git a/picoquic/picoquic.h b/picoquic/picoquic.h
index 9f714493..a83bb794 100644
--- a/picoquic/picoquic.h
+++ b/picoquic/picoquic.h
@@ -348,6 +348,8 @@ int picoquic_set_verify_certificate_callback(picoquic_quic_t* quic, picoquic_ver
/* Set client authentication in TLS (if enabled, client is required to send certificates). */
void picoquic_set_client_authentication(picoquic_quic_t* quic, int client_authentication);
+/* Set default padding policy for the context */
+
/* Connection context creation and registration */
picoquic_cnx_t* picoquic_create_cnx(picoquic_quic_t* quic,
picoquic_connection_id_t initial_cnx_id, picoquic_connection_id_t remote_cnx_id,
@@ -380,6 +382,9 @@ picoquic_cnx_t* picoquic_get_earliest_cnx_to_wake(picoquic_quic_t* quic, uint64_
picoquic_state_enum picoquic_get_cnx_state(picoquic_cnx_t* cnx);
+void picoquic_cnx_set_padding_policy(picoquic_cnx_t * cnx, uint32_t padding_multiple, uint32_t padding_minsize);
+void picoquic_cnx_get_padding_policy(picoquic_cnx_t * cnx, uint32_t * padding_multiple, uint32_t * padding_minsize);
+
int picoquic_tls_is_psk_handshake(picoquic_cnx_t* cnx);
int picoquic_tls_is_early_data_skipped(picoquic_cnx_t* cnx);
diff --git a/picoquic/picoquic_internal.h b/picoquic/picoquic_internal.h
index 3d4c0ea8..eb6a982c 100644
--- a/picoquic/picoquic_internal.h
+++ b/picoquic/picoquic_internal.h
@@ -313,8 +313,9 @@ typedef struct st_picoquic_quic_t {
char const* ticket_file_name;
picoquic_stored_ticket_t* p_first_ticket;
uint32_t mtu_max;
-
uint32_t flags;
+ uint32_t padding_multiple_default;
+ uint32_t padding_minsize_default;
picoquic_stateless_packet_t* pending_stateless_packet;
@@ -623,6 +624,10 @@ typedef struct st_picoquic_cnx_t {
/* Local and remote parameters */
picoquic_tp_t local_parameters;
picoquic_tp_t remote_parameters;
+ /* Padding policy */
+ uint32_t padding_multiple;
+ uint32_t padding_minsize;
+
/* On clients, document the SNI and ALPN expected from the server */
/* TODO: there may be a need to propose multiple ALPN */
char const* sni;
diff --git a/picoquic/quicctx.c b/picoquic/quicctx.c
index e1168ed5..ab72d6c8 100644
--- a/picoquic/quicctx.c
+++ b/picoquic/quicctx.c
@@ -203,6 +203,8 @@ picoquic_quic_t* picoquic_create(uint32_t nb_connections,
quic->cnx_id_callback_ctx = cnx_id_callback_ctx;
quic->p_simulated_time = p_simulated_time;
quic->local_ctx_length = 8; /* TODO: should be lower on clients-only implementation */
+ quic->padding_multiple_default = 0; /* TODO: consider default = 128 */
+ quic->padding_minsize_default = PICOQUIC_RESET_PACKET_MIN_SIZE;
if (cnx_id_callback != NULL) {
quic->flags |= picoquic_context_unconditional_cnx_id;
@@ -273,6 +275,12 @@ int picoquic_set_default_tp(picoquic_quic_t* quic, picoquic_tp_t * tp)
return ret;
}
+void picoquic_set_default_padding(picoquic_quic_t* quic, uint32_t padding_multiple, uint32_t padding_minsize)
+{
+ quic->padding_minsize_default = padding_minsize;
+ quic->padding_multiple_default = padding_multiple;
+}
+
void picoquic_free(picoquic_quic_t* quic)
{
if (quic != NULL) {
@@ -1326,6 +1334,10 @@ picoquic_cnx_t* picoquic_create_cnx(picoquic_quic_t* quic,
cnx->max_stream_id_bidir_remote = (cnx->client_mode)?4:0;
cnx->max_stream_id_unidir_remote = 0;
+ /* Initialize padding policy to default for context */
+ cnx->padding_multiple = quic->padding_multiple_default;
+ cnx->padding_minsize = quic->padding_minsize_default;
+
if (sni != NULL) {
cnx->sni = picoquic_string_duplicate(sni);
}
@@ -1560,6 +1572,18 @@ uint64_t picoquic_is_0rtt_available(picoquic_cnx_t* cnx)
return (cnx->crypto_context[1].aead_encrypt == NULL) ? 0 : 1;
}
+void picoquic_cnx_set_padding_policy(picoquic_cnx_t * cnx, uint32_t padding_multiple, uint32_t padding_minsize)
+{
+ cnx->padding_multiple = padding_multiple;
+ cnx->padding_minsize = padding_minsize;
+}
+
+void picoquic_cnx_get_padding_policy(picoquic_cnx_t * cnx, uint32_t * padding_multiple, uint32_t * padding_minsize)
+{
+ *padding_multiple = cnx->padding_multiple;
+ *padding_minsize = cnx->padding_minsize;
+}
+
/*
* Provide clock time
*/
diff --git a/picoquic/sender.c b/picoquic/sender.c
index 065bbf54..0d438f06 100644
--- a/picoquic/sender.c
+++ b/picoquic/sender.c
@@ -174,6 +174,43 @@ int picoquic_stop_sending(picoquic_cnx_t* cnx,
return ret;
}
+/*
+ * Manage content padding
+ */
+
+uint32_t picoquic_pad_to_target_length(uint8_t * bytes, uint32_t length, uint32_t target)
+{
+ if (length < target) {
+ memset(bytes + length, 0, target - length);
+ length = target;
+ }
+
+ return length;
+}
+
+uint32_t picoquic_pad_to_policy(picoquic_cnx_t * cnx, uint8_t * bytes, uint32_t length, uint32_t max_length)
+{
+ uint32_t target = cnx->padding_minsize;
+
+ if (length > target && cnx->padding_multiple != 0) {
+ uint32_t delta = (length - target) % cnx->padding_multiple;
+
+ if (delta == 0) {
+ target = length;
+ }
+ else {
+ target = length + cnx->padding_multiple - delta;
+ }
+ }
+
+ if (target > max_length) {
+ target = max_length;
+ }
+
+ return picoquic_pad_to_target_length(bytes, length, target);
+}
+
+
/*
* Packet management
*/
@@ -874,9 +911,8 @@ int picoquic_retransmit_needed(picoquic_cnx_t* cnx,
if (ret == 0 && !frame_is_pure_ack) {
if (picoquic_is_stream_frame_unlimited(&p->bytes[byte_index])) {
/* Need to PAD to the end of the frame to avoid sending extra bytes */
- while (checksum_length + length + frame_length < send_buffer_max) {
- new_bytes[length] = picoquic_frame_type_padding;
- length++;
+ if (checksum_length + length + frame_length < send_buffer_max) {
+ length = picoquic_pad_to_target_length(new_bytes, length, (uint32_t)(send_buffer_max - checksum_length - frame_length));
}
}
memcpy(&new_bytes[length], &p->bytes[byte_index], frame_length);
@@ -1161,9 +1197,10 @@ int picoquic_prepare_packet_0rtt(picoquic_cnx_t* cnx, picoquic_path_t * path_x,
}
/* Add padding if required */
if (padding_required) {
- while (length < send_buffer_max - checksum_overhead) {
- bytes[length++] = 0;
- }
+ length = picoquic_pad_to_target_length(bytes, length, (uint32_t)(send_buffer_max - checksum_overhead));
+ }
+ else {
+ length = picoquic_pad_to_policy(cnx, bytes, length, (uint32_t)(send_buffer_max - checksum_overhead));
}
}
@@ -1477,10 +1514,11 @@ int picoquic_prepare_packet_client_init(picoquic_cnx_t* cnx, picoquic_path_t * p
cnx->original_cnxid.id_len != 0)) {
/* Pad to minimum packet length. But don't do that if the
* initial packet will be coalesced with 0-RTT packet */
- while (length < send_buffer_max - checksum_overhead) {
- bytes[length++] = 0;
- }
- }
+ length = picoquic_pad_to_target_length(bytes, length, (uint32_t)(send_buffer_max - checksum_overhead));
+ }
+ else {
+ length = picoquic_pad_to_policy(cnx, bytes, length, (uint32_t)(send_buffer_max - checksum_overhead));
+ }
if (packet_type == picoquic_packet_0rtt_protected) {
cnx->nb_zero_rtt_sent++;
@@ -2265,12 +2303,7 @@ int picoquic_prepare_packet_ready(picoquic_cnx_t* cnx, picoquic_path_t * path_x,
}
if (length > header_length) {
- if ((length + checksum_overhead) <= PICOQUIC_RESET_PACKET_MIN_SIZE) {
- uint32_t pad_size = PICOQUIC_RESET_PACKET_MIN_SIZE - checksum_overhead - length + 1;
- for (uint32_t i = 0; i < pad_size; i++) {
- bytes[length++] = 0;
- }
- }
+ length = picoquic_pad_to_policy(cnx, bytes, length, (uint32_t)(send_buffer_max - checksum_overhead));
}
else if (ret == 0 && send_buffer_max > path_x->send_mtu
&& path_x->cwin > path_x->bytes_in_transit && picoquic_is_mtu_probe_needed(cnx, path_x)) {
@@ -2497,9 +2530,7 @@ int picoquic_prepare_probe(picoquic_cnx_t* cnx,
/* Pack to min length, to verify that the path can carry a min length packet */
if (length + checksum_overhead < PICOQUIC_INITIAL_MTU_IPV6) {
- uint32_t pad_size = PICOQUIC_INITIAL_MTU_IPV6 - checksum_overhead - length;
- memset(&bytes[length], 0, pad_size);
- length += pad_size;
+ length = picoquic_pad_to_target_length(bytes, length, PICOQUIC_INITIAL_MTU_IPV6 - checksum_overhead);
}
/* set the return addresses */
--
GitLab