From fd7cdc3e7099c113209de98829e51eaf85d0e3ae Mon Sep 17 00:00:00 2001
From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Tue, 24 Aug 2021 15:13:20 +0200
Subject: [PATCH] MINOR: qpack: generate headers list on decoder

TMP -> non-free strdup
TMP -> currently only support indexed field line or literal field line
with name reference
---
 include/haproxy/qpack-dec.h |  4 +++-
 src/h3.c                    |  4 +++-
 src/qpack-dec.c             | 29 ++++++++++++++++++++++++-----
 3 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/include/haproxy/qpack-dec.h b/include/haproxy/qpack-dec.h
index 517d617f9..f45246f76 100644
--- a/include/haproxy/qpack-dec.h
+++ b/include/haproxy/qpack-dec.h
@@ -24,6 +24,7 @@
 #include <haproxy/mux_quic-t.h>
 
 struct h3_uqs;
+struct http_hdr;
 
 /* Internal QPACK processing errors.
  *Nothing to see with the RFC.
@@ -43,7 +44,8 @@ struct qpack_dec {
 	uint64_t krc;
 };
 
-int qpack_decode_fs(const unsigned char *buf, uint64_t len, struct buffer *tmp);
+int qpack_decode_fs(const unsigned char *buf, uint64_t len, struct buffer *tmp,
+                    struct http_hdr *list);
 int qpack_decode_enc(struct h3_uqs *h3_uqs, void *ctx);
 int qpack_decode_dec(struct h3_uqs *h3_uqs, void *ctx);
 
diff --git a/src/h3.c b/src/h3.c
index c90e63a68..78d43a71a 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -121,6 +121,8 @@ static int h3_decode_qcs(struct qcs *qcs, void *ctx)
 {
 	struct buffer *rxbuf = &qcs->rx.buf;
 	struct h3 *h3 = ctx;
+	struct http_hdr list[global.tune.max_http_hdr];
+	int hdr_idx;
 
 	h3_debug_printf(stderr, "%s: STREAM ID: %llu\n", __func__, qcs->by_id.key);
 	if (!b_data(rxbuf))
@@ -152,7 +154,7 @@ static int h3_decode_qcs(struct qcs *qcs, void *ctx)
 			size_t len = b_data(rxbuf);
 			struct buffer *tmp = get_trash_chunk();
 
-			if (qpack_decode_fs(buf, len, tmp) < 0) {
+			if (qpack_decode_fs(buf, len, tmp, list) < 0) {
 				h3->err = QPACK_DECOMPRESSION_FAILED;
 				return -1;
 			}
diff --git a/src/qpack-dec.c b/src/qpack-dec.c
index 95ec720b7..54e7f164a 100644
--- a/src/qpack-dec.c
+++ b/src/qpack-dec.c
@@ -29,8 +29,10 @@
 #include <haproxy/h3.h>
 #include <haproxy/qpack-t.h>
 #include <haproxy/qpack-dec.h>
+#include <haproxy/qpack-tbl.h>
 #include <haproxy/hpack-huff.h>
 #include <haproxy/hpack-tbl.h>
+#include <haproxy/http-hdr.h>
 #include <haproxy/tools.h>
 
 #define DEBUG_HPACK
@@ -177,12 +179,14 @@ static int qpack_decode_fs_pfx(uint64_t *enc_ric, uint64_t *db, int *sign_bit,
 /* Decode a field section from <len> bytes length <raw> buffer.
  * Produces the output into <tmp> buffer.
  */
-int qpack_decode_fs(const unsigned char *raw, size_t len, struct buffer *tmp)
+int qpack_decode_fs(const unsigned char *raw, size_t len, struct buffer *tmp,
+                    struct http_hdr *list)
 {
 	uint64_t enc_ric, db;
 	int s;
 	unsigned int efl_type;
 	int ret;
+	int hdr_idx = 0;
 
 	qpack_debug_hexdump(stderr, "[QPACK-DEC-FS] ", (const char *)raw, 0, len);
 
@@ -227,7 +231,8 @@ int qpack_decode_fs(const unsigned char *raw, size_t len, struct buffer *tmp)
 			/* XXX Value string XXX */
 			raw += length;
 			len -= length;
-		} else if (efl_type == QPACK_IFL_WPBI) {
+		}
+		else if (efl_type == QPACK_IFL_WPBI) {
 			/* Indexed field line with post-base index */
 			uint64_t index;
 
@@ -240,7 +245,8 @@ int qpack_decode_fs(const unsigned char *raw, size_t len, struct buffer *tmp)
 			}
 
 			qpack_debug_printf(stderr, " index=%llu", (unsigned long long)index);
-		} else if (efl_type & QPACK_IFL_BIT) {
+		}
+		else if (efl_type & QPACK_IFL_BIT) {
 			/* Indexed field line */
 			uint64_t index;
 			unsigned int t;
@@ -254,8 +260,12 @@ int qpack_decode_fs(const unsigned char *raw, size_t len, struct buffer *tmp)
 				goto out;
 			}
 
+			if (t)
+				list[hdr_idx++] = qpack_sht[index];
+
 			qpack_debug_printf(stderr,  " t=%d index=%llu", !!t, (unsigned long long)index);
-		} else if (efl_type & QPACK_LFL_WNR_BIT) {
+		}
+		else if (efl_type & QPACK_LFL_WNR_BIT) {
 			/* Literal field line with name reference */
 			uint64_t index, length;
 			unsigned int t, n, h;
@@ -270,6 +280,9 @@ int qpack_decode_fs(const unsigned char *raw, size_t len, struct buffer *tmp)
 				goto out;
 			}
 
+			if (t)
+				list[hdr_idx] = qpack_sht[index];
+
 			qpack_debug_printf(stderr, " n=%d t=%d index=%llu", !!n, !!t, (unsigned long long)index);
 			h = *raw & 0x80;
 			length = qpack_get_varint(&raw, &len, 7);
@@ -298,11 +311,14 @@ int qpack_decode_fs(const unsigned char *raw, size_t len, struct buffer *tmp)
 				}
 
 				qpack_debug_printf(stderr, " [name huff %d->%d '%s']", (int)length, (int)nlen, trash);
+				list[hdr_idx].v = ist(strdup(trash));
 			}
 			/* XXX Value string XXX */
 			raw += length;
 			len -= length;
-		} else if (efl_type & QPACK_LFL_WLN_BIT) {
+			++hdr_idx;
+		}
+		else if (efl_type & QPACK_LFL_WLN_BIT) {
 			/* Literal field line with literal name */
 			unsigned int n, hname, hvalue;
 			uint64_t name_len, value_len;
@@ -338,6 +354,9 @@ int qpack_decode_fs(const unsigned char *raw, size_t len, struct buffer *tmp)
 		qpack_debug_printf(stderr, "\n");
 	}
 
+	/* put an end marker */
+	list[hdr_idx].n = list[hdr_idx].v = IST_NULL;
+
  out:
 	qpack_debug_printf(stderr, "-- done: ret=%d\n", ret);
 	return ret;