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From: Enrique Llorente <ellorent@redhat.com>
To: passt-dev@passt.top
Cc: Enrique Llorente <ellorent@redhat.com>
Subject: [PATCH v2] dhcp: Remove option 255 length byte
Date: Mon, 17 Feb 2025 10:28:14 +0100	[thread overview]
Message-ID: <20250217092814.424375-1-ellorent@redhat.com> (raw)

The option 255 (end of options) do not need the length byte, this change
remove that allowing to have one extra byte at other dynamic options.

Signed-off-by: Enrique Llorente <ellorent@redhat.com>
---
 dhcp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/dhcp.c b/dhcp.c
index 401cb5b..4a209f1 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -64,9 +64,9 @@ static struct opt opts[255];
 #define OPT_MIN		60 /* RFC 951 */
 
 /* Total option size (excluding end option) is 576 (RFC 2131), minus
- * offset of options (268), minus end option and its length (2).
+ * offset of options (268), minus end option (1).
  */
-#define OPT_MAX		306
+#define OPT_MAX		307
 
 /**
  * dhcp_init() - Initialise DHCP options
@@ -127,7 +127,7 @@ struct msg {
 	uint8_t sname[64];
 	uint8_t file[128];
 	uint32_t magic;
-	uint8_t o[OPT_MAX + 2 /* End option and its length */ ];
+	uint8_t o[OPT_MAX + 1 /* End option */ ];
 } __attribute__((__packed__));
 
 /**
@@ -194,7 +194,6 @@ static int fill(struct msg *m)
 	}
 
 	m->o[offset++] = 255;
-	m->o[offset++] = 0;
 
 	if (offset < OPT_MIN) {
 		memset(&m->o[offset], 0, OPT_MIN - offset);
-- 
@@ -64,9 +64,9 @@ static struct opt opts[255];
 #define OPT_MIN		60 /* RFC 951 */
 
 /* Total option size (excluding end option) is 576 (RFC 2131), minus
- * offset of options (268), minus end option and its length (2).
+ * offset of options (268), minus end option (1).
  */
-#define OPT_MAX		306
+#define OPT_MAX		307
 
 /**
  * dhcp_init() - Initialise DHCP options
@@ -127,7 +127,7 @@ struct msg {
 	uint8_t sname[64];
 	uint8_t file[128];
 	uint32_t magic;
-	uint8_t o[OPT_MAX + 2 /* End option and its length */ ];
+	uint8_t o[OPT_MAX + 1 /* End option */ ];
 } __attribute__((__packed__));
 
 /**
@@ -194,7 +194,6 @@ static int fill(struct msg *m)
 	}
 
 	m->o[offset++] = 255;
-	m->o[offset++] = 0;
 
 	if (offset < OPT_MIN) {
 		memset(&m->o[offset], 0, OPT_MIN - offset);
-- 
2.47.0


             reply	other threads:[~2025-02-17  9:28 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-17  9:28 Enrique Llorente [this message]
2025-02-18  1:26 ` [PATCH v2] dhcp: Remove option 255 length byte David Gibson
2025-02-18  8:14 ` Stefano Brivio

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