From dde1301104e8a3523795c8f9c67d157d36ffd28c Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Sun, 18 Jun 2017 17:25:32 +0900
Subject: [PATCH] Add ACK frame parser
At the moment, it just extracts Largest Acknowledged. It is rather
implemented as place holder to parse incoming ACK frames without
error.
---
lib/includes/ngtcp2/ngtcp2.h | 6 +++
lib/ngtcp2_conv.c | 11 ++++
lib/ngtcp2_conv.h | 14 ++++++
lib/ngtcp2_pkt.c | 98 ++++++++++++++++++++++++++++++++++--
lib/ngtcp2_pkt.h | 46 ++++++++++++-----
tests/main.c | 4 +-
tests/ngtcp2_pkt_test.c | 20 ++++++++
tests/ngtcp2_pkt_test.h | 1 +
tests/ngtcp2_test_helper.c | 17 +++++++
tests/ngtcp2_test_helper.h | 10 ++++
10 files changed, 208 insertions(+), 19 deletions(-)
diff --git a/lib/includes/ngtcp2/ngtcp2.h b/lib/includes/ngtcp2/ngtcp2.h
index 1c6d50c3..bafcaaf1 100644
--- a/lib/includes/ngtcp2/ngtcp2.h
+++ b/lib/includes/ngtcp2/ngtcp2.h
@@ -137,9 +137,15 @@ typedef struct {
const uint8_t *data;
} ngtcp2_stream;
+typedef struct {
+ uint8_t type;
+ uint64_t largest_ack;
+} ngtcp2_ack;
+
typedef union {
uint8_t type;
ngtcp2_stream stream;
+ ngtcp2_ack ack;
} ngtcp2_frame;
/**
diff --git a/lib/ngtcp2_conv.c b/lib/ngtcp2_conv.c
index 88e99e76..0a090941 100644
--- a/lib/ngtcp2_conv.c
+++ b/lib/ngtcp2_conv.c
@@ -45,6 +45,12 @@ uint64_t ngtcp2_get_uint64(const uint8_t *p) {
return bswap64(n);
}
+uint64_t ngtcp2_get_uint48(const uint8_t *p) {
+ uint64_t n = 0;
+ memcpy(((uint8_t *)&n) + 2, p, 6);
+ return bswap64(n);
+}
+
uint32_t ngtcp2_get_uint32(const uint8_t *p) {
uint32_t n;
memcpy(&n, p, 4);
@@ -68,6 +74,11 @@ uint8_t *ngtcp2_put_uint64be(uint8_t *p, uint64_t n) {
return ngtcp2_cpymem(p, (const uint8_t *)&n, sizeof(n));
}
+uint8_t *ngtcp2_put_uint48be(uint8_t *p, uint64_t n) {
+ n = bswap64(n);
+ return ngtcp2_cpymem(p, ((const uint8_t *)&n) + 2, 6);
+}
+
uint8_t *ngtcp2_put_uint32be(uint8_t *p, uint32_t n) {
n = htonl(n);
return ngtcp2_cpymem(p, (const uint8_t *)&n, sizeof(n));
diff --git a/lib/ngtcp2_conv.h b/lib/ngtcp2_conv.h
index 664001f1..456ea9fd 100644
--- a/lib/ngtcp2_conv.h
+++ b/lib/ngtcp2_conv.h
@@ -38,6 +38,13 @@
*/
uint64_t ngtcp2_get_uint64(const uint8_t *p);
+/*
+ * ngtcp2_get_uint48 reads 6 bytes from |p| as 48 bits unsigned
+ * integer encoded as network byte order, and returns it in host byte
+ * order.
+ */
+uint64_t ngtcp2_get_uint48(const uint8_t *p);
+
/*
* ngtcp2_get_uint32 reads 4 bytes from |p| as 32 bits unsigned
* integer encoded as network byte order, and returns it in host byte
@@ -66,6 +73,13 @@ uint16_t ngtcp2_get_uint16(const uint8_t *p);
*/
uint8_t *ngtcp2_put_uint64be(uint8_t *p, uint64_t n);
+/*
+ * ngtcp2_put_uint48be writes |n| in host byte order in |p| in network
+ * byte order. It writes only least significant 48 bits. It returns
+ * the one beyond of the last written position.
+ */
+uint8_t *ngtcp2_put_uint48be(uint8_t *p, uint64_t n);
+
/*
* ngtcp2_put_uint32be writes |n| in host byte order in |p| in network
* byte order. It returns the one beyond of the last written
diff --git a/lib/ngtcp2_pkt.c b/lib/ngtcp2_pkt.c
index acadcb44..5b90e30c 100644
--- a/lib/ngtcp2_pkt.c
+++ b/lib/ngtcp2_pkt.c
@@ -389,11 +389,99 @@ ssize_t ngtcp2_pkt_decode_stream_frame(ngtcp2_frame *dest,
}
ssize_t ngtcp2_pkt_decode_ack_frame(ngtcp2_frame *dest, const uint8_t *payload,
- size_t len) {
- (void)dest;
- (void)payload;
- (void)len;
- return -1;
+ size_t payloadlen) {
+ uint8_t type;
+ size_t num_blks = 0;
+ size_t num_ts;
+ size_t lalen;
+ size_t abllen;
+ size_t len = 4;
+ const uint8_t *p;
+
+ /* We can expect at least 3 bytes (type, NumTS, and LA) */
+ if (payloadlen < 3 || !has_mask(payload[0], NGTCP2_FRAME_ACK)) {
+ return NGTCP2_ERR_INVALID_ARGUMENT;
+ }
+
+ p = &payload[0];
+
+ type = *p++;
+
+ if (type & NGTCP2_ACK_N_BIT) {
+ num_blks = *p++;
+ ++len;
+ }
+
+ num_ts = *p++;
+
+ switch ((type & NGTCP2_ACK_LL_MASK) >> 2) {
+ case 0x00:
+ lalen = 1;
+ break;
+ case 0x01:
+ lalen = 2;
+ break;
+ case 0x02:
+ lalen = 4;
+ break;
+ case 0x03:
+ lalen = 6;
+ break;
+ }
+
+ len += lalen;
+
+ switch (type & NGTCP2_ACK_MM_MASK) {
+ case 0x00:
+ abllen = 1;
+ break;
+ case 0x01:
+ abllen = 2;
+ break;
+ case 0x02:
+ abllen = 4;
+ break;
+ case 0x03:
+ abllen = 6;
+ break;
+ }
+
+ /* Length of ACK Block Section */
+ /* First ACK Block Length */
+ len += lalen;
+ len += num_blks * abllen;
+
+ /* Length of Timestamp Section */
+ if (num_ts > 0) {
+ len += num_ts * 3 + 2;
+ }
+
+ if (payloadlen < len) {
+ return NGTCP2_ERR_INVALID_ARGUMENT;
+ }
+
+ dest->type = NGTCP2_FRAME_ACK;
+
+ switch (lalen) {
+ case 1:
+ dest->ack.largest_ack = *p;
+ break;
+ case 2:
+ dest->ack.largest_ack = ngtcp2_get_uint16(p);
+ break;
+ case 4:
+ dest->ack.largest_ack = ngtcp2_get_uint32(p);
+ break;
+ case 6:
+ dest->ack.largest_ack = ngtcp2_get_uint48(p);
+ break;
+ }
+
+ p += lalen;
+
+ /* TODO Parse remaining fields */
+
+ return (ssize_t)len;
}
ssize_t ngtcp2_pkt_decode_padding_frame(ngtcp2_frame *dest,
diff --git a/lib/ngtcp2_pkt.h b/lib/ngtcp2_pkt.h
index 37140a9d..43373290 100644
--- a/lib/ngtcp2_pkt.h
+++ b/lib/ngtcp2_pkt.h
@@ -45,6 +45,10 @@
#define NGTCP2_STREAM_OO_MASK 0x06
#define NGTCP2_STREAM_D_BIT 0x01
+#define NGTCP2_ACK_N_BIT 0x10
+#define NGTCP2_ACK_LL_MASK 0x0c
+#define NGTCP2_ACK_MM_MASK 0x03
+
/*
* ngtcp2_pkt_hd_init initializes |hd| with the given values.
*/
@@ -120,49 +124,65 @@ ssize_t ngtcp2_pkt_decode_stream_frame(ngtcp2_frame *dest,
const uint8_t *payload,
size_t payloadlen);
+/*
+ * ngtcp2_pkt_decode_ack_frame decodes ACK frame from |payload| of
+ * length |payloadlen|. The result is stored in the object pointed by
+ * |dest|. ACK frame must start at `payload[0]`. This function
+ * returns when it decodes one ACK frame, and returns the exact number
+ * of bytes for one ACK frame if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGTCP2_ERR_INVALID_ARGUMENT Type indicates that payload does not
+ * include ACK frame; or Payload is too short to include ACK frame
+ */
ssize_t ngtcp2_pkt_decode_ack_frame(ngtcp2_frame *dest, const uint8_t *payload,
- size_t len);
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_padding_frame(ngtcp2_frame *dest,
- const uint8_t *payload, size_t len);
+ const uint8_t *payload,
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_rst_stream_frame(ngtcp2_frame *dest,
- const uint8_t *payload, size_t len);
+ const uint8_t *payload,
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_connection_close_frame(ngtcp2_frame *dest,
const uint8_t *payload,
- size_t len);
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_goaway_frame(ngtcp2_frame *dest,
- const uint8_t *payload, size_t len);
+ const uint8_t *payload,
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_max_data_frame(ngtcp2_frame *dest,
- const uint8_t *payload, size_t len);
+ const uint8_t *payload,
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_max_stream_data_frame(ngtcp2_frame *dest,
const uint8_t *payload,
- size_t len);
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_max_stream_id_frame(ngtcp2_frame *dest,
const uint8_t *payload,
- size_t len);
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_ping_frame(ngtcp2_frame *dest, const uint8_t *payload,
- size_t len);
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_blocked_frame(ngtcp2_frame *dest,
- const uint8_t *payload, size_t len);
+ const uint8_t *payload,
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_stream_blocked_frame(ngtcp2_frame *dest,
const uint8_t *payload,
- size_t len);
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_stream_id_needed_frame(ngtcp2_frame *dest,
const uint8_t *payload,
- size_t len);
+ size_t payloadlen);
ssize_t ngtcp2_pkt_decode_new_connection_id_frame(ngtcp2_frame *dest,
const uint8_t *payload,
- size_t len);
+ size_t payloadlen);
#endif /* NGTCP2_PKT_H */
diff --git a/tests/main.c b/tests/main.c
index fa37fc07..fdb34aed 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -58,7 +58,9 @@ int main() {
!CU_add_test(pSuite, "pkt_decode_hd_short",
test_ngtcp2_pkt_decode_hd_short) ||
!CU_add_test(pSuite, "pkt_decode_stream_frame",
- test_ngtcp2_pkt_decode_stream_frame)) {
+ test_ngtcp2_pkt_decode_stream_frame) ||
+ !CU_add_test(pSuite, "pkt_decode_ack_frame",
+ test_ngtcp2_pkt_decode_ack_frame)) {
CU_cleanup_registry();
return CU_get_error();
}
diff --git a/tests/ngtcp2_pkt_test.c b/tests/ngtcp2_pkt_test.c
index 7cf26b66..94609a81 100644
--- a/tests/ngtcp2_pkt_test.c
+++ b/tests/ngtcp2_pkt_test.c
@@ -258,3 +258,23 @@ void test_ngtcp2_pkt_decode_stream_frame(void) {
memset(&fm, 0, sizeof(fm));
}
+
+void test_ngtcp2_pkt_decode_ack_frame(void) {
+ uint8_t buf[256];
+ size_t buflen;
+ ngtcp2_frame fm;
+ ssize_t rv;
+ size_t expectedlen;
+
+ /* 48 bits Largest Acknowledged + No Num Blocks + 0 NumTS*/
+ buflen = ngtcp2_t_encode_ack_frame(buf, 0xf1f2f3f4f5f6llu);
+
+ expectedlen = 1 + 1 + 6 + 2 + 6;
+
+ CU_ASSERT(expectedlen == buflen);
+
+ rv = ngtcp2_pkt_decode_ack_frame(&fm, buf, buflen);
+
+ CU_ASSERT((ssize_t)expectedlen == rv);
+ CU_ASSERT(0xf1f2f3f4f5f6llu == fm.ack.largest_ack);
+}
diff --git a/tests/ngtcp2_pkt_test.h b/tests/ngtcp2_pkt_test.h
index 1efcde5a..09c52c8b 100644
--- a/tests/ngtcp2_pkt_test.h
+++ b/tests/ngtcp2_pkt_test.h
@@ -32,5 +32,6 @@
void test_ngtcp2_pkt_decode_hd_long(void);
void test_ngtcp2_pkt_decode_hd_short(void);
void test_ngtcp2_pkt_decode_stream_frame(void);
+void test_ngtcp2_pkt_decode_ack_frame(void);
#endif /* NGTCP2_PKT_TEST_H */
diff --git a/tests/ngtcp2_test_helper.c b/tests/ngtcp2_test_helper.c
index e346e530..a75f013c 100644
--- a/tests/ngtcp2_test_helper.c
+++ b/tests/ngtcp2_test_helper.c
@@ -69,3 +69,20 @@ size_t ngtcp2_t_encode_stream_frame(uint8_t *out, uint8_t flags,
return (size_t)(p - out);
}
+
+size_t ngtcp2_t_encode_ack_frame(uint8_t *out, uint64_t largest_ack) {
+ uint8_t *p = out;
+
+ p = out;
+
+ *p++ = 0x0c | NGTCP2_FRAME_ACK;
+ /* NumTS */
+ *p++ = 0;
+ p = ngtcp2_put_uint48be(p, largest_ack);
+ p = ngtcp2_put_uint16be(p, 0);
+ /* TODO Draft-04 is pretty much ambiguous that whether the length of
+ First ACK Block Length is subject to LL or MM mask. */
+ p = ngtcp2_put_uint48be(p, 0);
+
+ return (size_t)(p - out);
+}
diff --git a/tests/ngtcp2_test_helper.h b/tests/ngtcp2_test_helper.h
index b43d7357..20b87da9 100644
--- a/tests/ngtcp2_test_helper.h
+++ b/tests/ngtcp2_test_helper.h
@@ -45,4 +45,14 @@ size_t ngtcp2_t_encode_stream_frame(uint8_t *out, uint8_t flags,
uint32_t stream_id, uint64_t offset,
uint16_t datalen);
+/*
+ * ngtcp2_t_encode_ack_frame encodes ACK frame into |out| with the
+ * given parameters. Currently, this function encodes |largest_ack|
+ * in 48 bits, and omits Num Blocks field. NumTS and ACK Delay fields
+ * are always 0.
+ *
+ * This function returns the number of bytes written to |out|.
+ */
+size_t ngtcp2_t_encode_ack_frame(uint8_t *out, uint64_t largest_ack);
+
#endif /* NGTCP2_TEST_HELPER_H */
--
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