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[4/6] NET:AX25:ROSE Fixes to rose_header

Message ID 201607160944.u6G9ixOJ015059@ux4.g1sog
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Richard Stearn July 16, 2016, 9:44 a.m. UTC 
Subject: [PATCH 4/6]NET:AX25:ROSE Fixes to rose_header
Adds comments on the header fields. Removes address copy.

Added comments detailing the ROSE header fields being built.
Removes an address copy that is irrelevant for this ROSE header as there are no
addresses in the header and the copy corrupts the data field of the packet.

Signed-off-by: Richard Stearn <richard@rns-stearn.demon.co.uk>
---
 net/rose/rose_dev.c |   13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

There are no hardware address fields in the packet. The memcpy corrupts the
packet data.
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Patch

diff --git a/net/rose/rose_dev.c b/net/rose/rose_dev.c
index 369ca81..44eca10 100644
--- a/net/rose/rose_dev.c
+++ b/net/rose/rose_dev.c
@@ -41,14 +41,11 @@  static int rose_header(struct sk_buff *skb, struct net_device *dev,
 {
 	unsigned char *buff = skb_push(skb, ROSE_MIN_LEN + 2);
 
-	if (daddr)
-		memcpy(buff + 7, daddr, dev->addr_len);
-
-	*buff++ = ROSE_GFI | ROSE_Q_BIT;
-	*buff++ = 0x00;
-	*buff++ = ROSE_DATA;
-	*buff++ = 0x7F;
-	*buff++ = AX25_P_IP;
+	*buff++ = ROSE_GFI | ROSE_Q_BIT; /* GFI and upper 4 bits of the LCI */
+	*buff++ = 0x00;			 /* lower 8 bits of the LCI */
+	*buff++ = ROSE_DATA;		 /* P(S), M, P(R) and data flag */
+	*buff++ = 0x7F;			 /* magic marker */
+	*buff++ = AX25_P_IP;		 /* this is an IP packet */
 
 	if (daddr != NULL)
 		return 37;