Attachment 314534 Details for Bug 249001 – The patch ensures the MPLS data are not included to the chk_sum function.

[patch] The patch ensures the MPLS data are not included to the chk_sum function.

traceroute-1.4a12-cksumfix.patch (text/plain), 1.08 KB, created by Jiri Skala on 2008-08-19 12:06:27 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Jiri Skala

Created: 2008-08-19 12:06:27 UTC

Size: 1.08 KB

patch

obsolete

>diff -up traceroute-1.4a12/traceroute.c.cksumfix traceroute-1.4a12/traceroute.c
>--- traceroute-1.4a12/traceroute.c.cksumfix	2008-06-12 09:33:14.000000000 +0200
>+++ traceroute-1.4a12/traceroute.c	2008-06-12 09:40:05.000000000 +0200
>@@ -1492,13 +1492,25 @@ packet_ok(register u_char *buf, int cc, 
> 	}
> 	cc -= hlen;
> 	icp = (struct icmp *)(buf + hlen);
>+	
>+	// get number of bytes to calculate checksum	
>+	int cksum_len = htons(ip->ip_len) - hlen;
>+
>+	// get number of bytes in the inner ip
>+	struct ip *hip = (struct ip *)(buf + hlen + sizeof(struct icmphdr));
>+	int sub_len = htons(hip->ip_len) + sizeof(struct icmphdr);
>+	
>+	// the inner ip is whole in the response => use it to calculate checksum
>+	if (sub_len < cksum_len)
>+		cksum_len = sub_len;
>+	
>+	// test checksum
>+	if (in_cksum((u_short *)icp, cksum_len))
>+		fprintf(stderr, "Icmp checksum is wrong\n");
> #else
> 	icp = (struct icmp *)buf;
> #endif
> 
>-	if (in_cksum((u_short *)icp, htons(ip->ip_len) - hlen))
>-		fprintf(stderr, "Icmp checksum is wrong\n");
>-
> 	type = icp->icmp_type;
> 	code = icp->icmp_code;
> 	/* Path MTU Discovery (RFC1191) */

Actions: View | Diff

Attachments on bug 249001: 308811 | 314534