From: itojun <itojun>
Date: Fri, 2 May 2003 08:13:54 +0000 (+0000)
Subject: verify/warn icmpv6 checksum.  from jinmei@kame
X-Git-Tag: tcpdump-3.8-bp~160
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/ba8e54bc85811d3a03d59c18ae61d57297fab3e8

verify/warn icmpv6 checksum.  from jinmei@kame
---

diff --git a/interface.h b/interface.h
index 07378f72..29b6f9b2 100644
--- a/interface.h
+++ b/interface.h
@@ -18,7 +18,7 @@
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * @(#) $Header: /tcpdump/master/tcpdump/interface.h,v 1.208 2003-05-01 18:02:12 guy Exp $ (LBL)
+ * @(#) $Header: /tcpdump/master/tcpdump/interface.h,v 1.209 2003-05-02 08:13:54 itojun Exp $ (LBL)
  */
 
 #ifndef tcpdump_interface_h
@@ -312,7 +312,7 @@ extern int hbhopt_print(const u_char *);
 extern int dstopt_print(const u_char *);
 extern int frag6_print(const u_char *, const u_char *);
 extern int mobility_print(const u_char *, const u_char *);
-extern void icmp6_print(const u_char *, const u_char *);
+extern void icmp6_print(const u_char *, const u_char *, int);
 extern void ripng_print(const u_char *, unsigned int);
 extern int rt6_print(const u_char *, const u_char *);
 extern void ospf6_print(const u_char *, u_int);
diff --git a/print-icmp6.c b/print-icmp6.c
index ce7474f9..5b8b44f5 100644
--- a/print-icmp6.c
+++ b/print-icmp6.c
@@ -21,7 +21,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-icmp6.c,v 1.69 2003-03-13 07:36:56 guy Exp $";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-icmp6.c,v 1.70 2003-05-02 08:13:55 itojun Exp $";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -100,8 +100,51 @@ print_lladdr(const u_int8_t *p, size_t l)
 	}
 }
 
+static int icmp6_cksum(const struct ip6_hdr *ip6, const struct icmp6_hdr *icp,
+	int len)
+{
+	int i;
+	register const u_int16_t *sp;
+	u_int32_t sum;
+	union {
+		struct {
+			struct in6_addr ph_src;
+			struct in6_addr ph_dst;
+			u_int32_t	ph_len;
+			u_int8_t	ph_zero[3];
+			u_int8_t	ph_nxt;
+		} ph;
+		u_int16_t pa[20];
+	} phu;
+
+	/* pseudo-header */
+	memset(&phu, 0, sizeof(phu));
+	phu.ph.ph_src = ip6->ip6_src;
+	phu.ph.ph_dst = ip6->ip6_dst;
+	phu.ph.ph_len = htonl(len);
+	phu.ph.ph_nxt = IPPROTO_ICMPV6;
+
+	sum = 0;
+	for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++)
+		sum += phu.pa[i];
+
+	sp = (const u_int16_t *)icp;
+
+	for (i = 0; i < (len & ~1); i += 2)
+		sum += *sp++;
+
+	if (len & 1)
+		sum += htons((*(const u_int8_t *)sp) << 8);
+
+	while (sum > 0xffff)
+		sum = (sum & 0xffff) + (sum >> 16);
+	sum = ~sum & 0xffff;
+
+	return (sum);
+}
+
 void
-icmp6_print(const u_char *bp, const u_char *bp2)
+icmp6_print(const u_char *bp, const u_char *bp2, int fragmented)
 {
 	const struct icmp6_hdr *dp;
 	const struct ip6_hdr *ip;
@@ -125,7 +168,20 @@ icmp6_print(const u_char *bp, const u_char *bp2)
 	else			/* XXX: jumbo payload case... */
 		icmp6len = snapend - bp;
 
-	TCHECK(dp->icmp6_code);
+	TCHECK(dp->icmp6_cksum);
+
+	if (vflag && !fragmented) {
+		int sum = dp->icmp6_cksum;
+
+		if (TTEST2(bp[0], icmp6len)) {
+			sum = icmp6_cksum(ip, dp, icmp6len);
+			if (sum != 0)
+				(void)printf("[bad icmp6 cksum %x!] ", sum);
+			else
+				(void)printf("[icmp6 sum ok] ");
+		}
+	}
+
 	switch (dp->icmp6_type) {
 	case ICMP6_DST_UNREACH:
 		TCHECK(oip->ip6_dst);
diff --git a/print-ip6.c b/print-ip6.c
index 846071da..9f5777a3 100644
--- a/print-ip6.c
+++ b/print-ip6.c
@@ -21,7 +21,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-ip6.c,v 1.28 2002-12-11 07:14:02 guy Exp $";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-ip6.c,v 1.29 2003-05-02 08:13:55 itojun Exp $";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -121,7 +121,7 @@ ip6_print(register const u_char *bp, register u_int length)
 				(const u_char *)ip6, fragmented);
 			goto end;
 		case IPPROTO_ICMPV6:
-			icmp6_print(cp, (const u_char *)ip6);
+			icmp6_print(cp, (const u_char *)ip6, fragmented);
 			goto end;
 		case IPPROTO_AH:
 			advance = ah_print(cp);