From: Christopher Faulet <cfaulet@haproxy.com>
Date: Wed, 8 Jul 2026 13:15:53 +0000 (+0200)
Subject: MEDIUM: htx: Insert headers and trailers before corresponding end-of block
X-Git-Tag: v3.5-dev8~172
X-Git-Url: https://git.kaiwu.me/?a=commitdiff_plain;h=0a9ecebdaaa36710cb4aae3a7a1feb8d9f9cf07f;p=haproxy.git

MEDIUM: htx: Insert headers and trailers before corresponding end-of block

htx_add_header() and htx_add_trailer() were updated to automatically insert
the block at the right place, just before the corresponding end-of block.
Indeed, it is invalid, unexepected and probably unsupported to insert a
header after the EOH block without moving it. So it is easier to handle it
in HTX function directly.

It means that http_add_header() was simplified.
---

diff --git a/include/haproxy/htx.h b/include/haproxy/htx.h
index 0d745b851..58a714a1e 100644
--- a/include/haproxy/htx.h
+++ b/include/haproxy/htx.h
@@ -521,12 +521,11 @@ static inline struct htx_sl *htx_add_stline(struct htx *htx, enum htx_blk_type t
 static inline struct htx_blk *htx_add_header(struct htx *htx, const struct ist name,
 					     const struct ist value)
 {
-	struct htx_blk *blk, *tailblk;
+	struct htx_blk *blk, *prevblk;
 
 	if (name.len > HTX_HDR_NAME_MAX_LEN || value.len > HTX_HDR_VALUE_MAX_LEN)
 		return NULL;
 
-	tailblk = htx_get_tail_blk(htx);
 	blk = htx_add_blk(htx, HTX_BLK_HDR, name.len + value.len);
 	if (!blk)
 		return NULL;
@@ -534,8 +533,17 @@ static inline struct htx_blk *htx_add_header(struct htx *htx, const struct ist n
 	blk->info += (value.len << 8) + name.len;
 	ist2bin_lc(htx_get_blk_ptr(htx, blk), name);
 	memcpy(htx_get_blk_ptr(htx, blk)  + name.len, value.ptr, value.len);
-	if (tailblk && htx_get_blk_type(tailblk) >= HTX_BLK_EOH)
-		htx->flags |= HTX_FL_UNORDERED;
+
+	for (prevblk = htx_get_prev_blk(htx, blk);
+	     prevblk && htx_get_blk_type(prevblk) > HTX_BLK_HDR;
+	     prevblk = htx_get_prev_blk(htx, blk)) {
+
+		/* Swap .addr and .info fields */
+		blk->addr ^= prevblk->addr; prevblk->addr ^= blk->addr; blk->addr ^= prevblk->addr;
+		blk->info ^= prevblk->info; prevblk->info ^= blk->info; blk->info ^= prevblk->info;
+		blk = prevblk;
+	}
+
 	return blk;
 }
 
@@ -545,12 +553,11 @@ static inline struct htx_blk *htx_add_header(struct htx *htx, const struct ist n
 static inline struct htx_blk *htx_add_trailer(struct htx *htx, const struct ist name,
 					      const struct ist value)
 {
-	struct htx_blk *blk, *tailblk;
+	struct htx_blk *blk, *prevblk;
 
 	if (name.len > HTX_HDR_NAME_MAX_LEN || value.len > HTX_HDR_VALUE_MAX_LEN)
 		return NULL;
 
-	tailblk = htx_get_tail_blk(htx);
 	blk = htx_add_blk(htx, HTX_BLK_TLR, name.len + value.len);
 	if (!blk)
 		return NULL;
@@ -558,8 +565,17 @@ static inline struct htx_blk *htx_add_trailer(struct htx *htx, const struct ist
 	blk->info += (value.len << 8) + name.len;
 	ist2bin_lc(htx_get_blk_ptr(htx, blk), name);
 	memcpy(htx_get_blk_ptr(htx, blk)  + name.len, value.ptr, value.len);
-	if (tailblk && htx_get_blk_type(tailblk) >= HTX_BLK_EOT)
-		htx->flags |= HTX_FL_UNORDERED;
+
+	for (prevblk = htx_get_prev_blk(htx, blk);
+	     prevblk && htx_get_blk_type(prevblk) > HTX_BLK_TLR;
+	     prevblk = htx_get_prev_blk(htx, blk)) {
+
+		/* Swap .addr and .info fields */
+		blk->addr ^= prevblk->addr; prevblk->addr ^= blk->addr; blk->addr ^= prevblk->addr;
+		blk->info ^= prevblk->info; prevblk->info ^= blk->info; blk->info ^= prevblk->info;
+		blk = prevblk;
+	}
+
 	return blk;
 }
 
diff --git a/src/http_htx.c b/src/http_htx.c
index b74f49dab..bc559221b 100644
--- a/src/http_htx.c
+++ b/src/http_htx.c
@@ -285,41 +285,12 @@ int http_match_header(const struct htx *htx, const struct my_regex *re, struct h
  */
 int http_add_header(struct htx *htx, const struct ist n, const struct ist v, int update_authority)
 {
-	struct htx_blk *blk;
-	struct htx_sl *sl;
-	enum htx_blk_type type = htx_get_tail_type(htx);
-	int32_t prev;
-
-	blk = htx_add_header(htx, n, v);
-	if (!blk)
+	if (!htx_add_header(htx, n, v))
 		goto fail;
 
-	if (unlikely(type < HTX_BLK_EOH))
-		goto end;
-
-	/* <blk> is the head, swap it iteratively with its predecessor to place
-	 * it just before the end-of-header block. So blocks remains ordered. */
-	for (prev = htx_get_prev(htx, htx->tail); prev != htx->first; prev = htx_get_prev(htx, prev)) {
-		struct htx_blk   *pblk = htx_get_blk(htx, prev);
-		enum htx_blk_type ptype = htx_get_blk_type(pblk);
-
-		/* Swap .addr and .info fields */
-		blk->addr ^= pblk->addr; pblk->addr ^= blk->addr; blk->addr ^= pblk->addr;
-		blk->info ^= pblk->info; pblk->info ^= blk->info; blk->info ^= pblk->info;
-
-		if (blk->addr == pblk->addr)
-			blk->addr += htx_get_blksz(pblk);
-
-		/* Stop when end-of-header is reached */
-		if (ptype == HTX_BLK_EOH)
-			break;
-
-		blk = pblk;
-	}
-
-  end:
 	if (update_authority) {
-		sl = http_get_stline(htx);
+		struct htx_sl *sl = http_get_stline(htx);
+
 		if (sl && (sl->flags & HTX_SL_F_HAS_AUTHORITY) && isteqi(n, ist("host"))) {
 			if (!http_update_authority(htx, sl, v))
 				goto fail;