Add TCP/UDP checksum display for v6 and clean up the checksum

calculation.  Mostly from tcpdump.org; ok jsing@

4 files changed, 97 insertions, 44 deletions

diff --git a/usr.sbin/tcpdump/interface.h b/usr.sbin/tcpdump/interface.h
index c6aee4b2c65..4475e742570 100644
--- a/usr.sbin/tcpdump/interface.h
+++ b/usr.sbin/tcpdump/interface.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: interface.h,v 1.59 2009/11/04 09:43:11 jsing Exp $	*/
+/*	$OpenBSD: interface.h,v 1.60 2010/01/12 06:10:33 naddy Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
@@ -20,7 +20,7 @@
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * @(#) $Id: interface.h,v 1.59 2009/11/04 09:43:11 jsing Exp $ (LBL)
+ * @(#) $Id: interface.h,v 1.60 2010/01/12 06:10:33 naddy Exp $ (LBL)
  */
 
 #ifndef tcpdump_interface_h
@@ -288,4 +288,4 @@ extern void ospf6_print(const u_char *, u_int);
 extern void dhcp6_print(const u_char *, u_int, u_short, u_short);
 #endif /*INET6*/
 
-extern u_short in_cksum(const u_short *addr, register int len, u_short csum);
+extern u_short in_cksum(const u_short *addr, register int len, int csum);
diff --git a/usr.sbin/tcpdump/print-ip.c b/usr.sbin/tcpdump/print-ip.c
index 9ea03d17154..dacbeef78e5 100644
--- a/usr.sbin/tcpdump/print-ip.c
+++ b/usr.sbin/tcpdump/print-ip.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: print-ip.c,v 1.35 2009/10/27 23:59:55 deraadt Exp $	*/
+/*	$OpenBSD: print-ip.c,v 1.36 2010/01/12 06:10:33 naddy Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
@@ -320,7 +320,7 @@ trunc:
  * don't modifiy the packet.
  */
 u_short
-in_cksum(const u_short *addr, register int len, u_short csum)
+in_cksum(const u_short *addr, register int len, int csum)
 {
 	int nleft = len;
 	const u_short *w = addr;
diff --git a/usr.sbin/tcpdump/print-tcp.c b/usr.sbin/tcpdump/print-tcp.c
index f393d1aff25..9b00d8244b2 100644
--- a/usr.sbin/tcpdump/print-tcp.c
+++ b/usr.sbin/tcpdump/print-tcp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: print-tcp.c,v 1.27 2009/10/27 23:59:56 deraadt Exp $	*/
+/*	$OpenBSD: print-tcp.c,v 1.28 2010/01/12 06:10:33 naddy Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
@@ -126,11 +126,8 @@ static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE];
 #endif
 #define NETBIOS_SSN_PORT 139
 
-static int tcp_cksum(register const struct ip *ip,
-		     register const struct tcphdr *tp,
-		     register int len)
+static int tcp_cksum(const struct ip *ip, const struct tcphdr *tp, int len)
 {
-	int i, tlen;
 	union phu {
 		struct phdr {
 			u_int32_t src;
@@ -141,35 +138,52 @@ static int tcp_cksum(register const struct ip *ip,
 		} ph;
 		u_int16_t pa[6];
 	} phu;
-	register const u_int16_t *sp;
+	const u_int16_t *sp;
 	u_int32_t sum;
-	tlen = ntohs(ip->ip_len) - ((const char *)tp-(const char*)ip);
 
 	/* pseudo-header.. */
-	phu.ph.len = htons(tlen);
+	phu.ph.len = htons((u_int16_t)len);
 	phu.ph.mbz = 0;
-	phu.ph.proto = ip->ip_p;
+	phu.ph.proto = IPPROTO_TCP;
 	memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t));
 	memcpy(&phu.ph.dst, &ip->ip_dst.s_addr, sizeof(u_int32_t));
 
 	sp = &phu.pa[0];
 	sum = sp[0]+sp[1]+sp[2]+sp[3]+sp[4]+sp[5];
 
-	sp = (const u_int16_t *)tp;
+	return in_cksum((u_short *)tp, len, sum);
+}
 
-	for (i=0; i<(tlen&~1); i+= 2)
-		sum += *sp++;
+#ifdef INET6
+static int tcp6_cksum(const struct ip6_hdr *ip6, const struct tcphdr *tp,
+		      u_int len)
+{
+	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;
+	size_t i;
+	u_int32_t sum = 0;
 
-	if (tlen & 1) {
-		sum += htons( (*(const char *)sp) << 8);
-	}
+	/* 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_TCP;
 
-	while (sum > 0xffff)
-		sum = (sum & 0xffff) + (sum >> 16);
-	sum = ~sum & 0xffff;
+	for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++)
+		sum += phu.pa[i];
 
-	return (sum);
+	return in_cksum((u_short *)tp, len, sum);
 }
+#endif
 
 
 void
@@ -416,6 +430,18 @@ tcp_print(register const u_char *bp, register u_int length,
 				(void)printf(" [tcp sum ok]");
 		}
 	}
+#ifdef INET6
+	if (ip6 && ip6->ip6_plen && vflag) {
+		int sum;
+		if (TTEST2(tp->th_sport, length)) {
+			sum = tcp6_cksum(ip6, tp, length);
+			if (sum != 0)
+				(void)printf(" [bad tcp cksum %x!]", sum);
+			else
+				(void)printf(" [tcp sum ok]");
+		}
+	}
+#endif
 
 	/* OS Fingerprint */
 	if (oflag && (flags & (TH_SYN|TH_ACK)) == TH_SYN) {
diff --git a/usr.sbin/tcpdump/print-udp.c b/usr.sbin/tcpdump/print-udp.c
index 3661d308d0e..4ddfbdeb732 100644
--- a/usr.sbin/tcpdump/print-udp.c
+++ b/usr.sbin/tcpdump/print-udp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: print-udp.c,v 1.33 2009/11/04 09:43:11 jsing Exp $	*/
+/*	$OpenBSD: print-udp.c,v 1.34 2010/01/12 06:10:33 naddy Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996
@@ -289,11 +289,8 @@ rtcp_print(const u_char *hdr, const u_char *ep)
 	return (hdr + len);
 }
 
-static int udp_cksum(register const struct ip *ip,
-		     register const struct udphdr *up,
-		     register int len)
+static int udp_cksum(const struct ip *ip, const struct udphdr *up, int len)
 {
-	int i, tlen;
 	union phu {
 		struct phdr {
 			u_int32_t src;
@@ -304,35 +301,52 @@ static int udp_cksum(register const struct ip *ip,
 		} ph;
 		u_int16_t pa[6];
 	} phu;
-	register const u_int16_t *sp;
+	const u_int16_t *sp;
 	u_int32_t sum;
-	tlen = ntohs(ip->ip_len) - ((const char *)up-(const char*)ip);
 
 	/* pseudo-header.. */
-	phu.ph.len = htons(tlen);
+	phu.ph.len = htons((u_int16_t)len);
 	phu.ph.mbz = 0;
-	phu.ph.proto = ip->ip_p;
+	phu.ph.proto = IPPROTO_UDP;
 	memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t));
 	memcpy(&phu.ph.dst, &ip->ip_dst.s_addr, sizeof(u_int32_t));
 
 	sp = &phu.pa[0];
 	sum = sp[0]+sp[1]+sp[2]+sp[3]+sp[4]+sp[5];
 
-	sp = (const u_int16_t *)up;
+	return in_cksum((u_short *)up, len, sum);
+}
 
-	for (i=0; i<(tlen&~1); i+= 2)
-		sum += *sp++;
+#ifdef INET6
+static int udp6_cksum(const struct ip6_hdr *ip6, const struct udphdr *up,
+	u_int len)
+{
+	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;
+	size_t i;
+	u_int32_t sum = 0;
 
-	if (tlen & 1) {
-		sum += htons( (*(const char *)sp) << 8);
-	}
+	/* 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_UDP;
 
-	while (sum > 0xffff)
-		sum = (sum & 0xffff) + (sum >> 16);
-	sum = ~sum & 0xffff;
+	for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++)
+		sum += phu.pa[i];
 
-	return (sum);
+	return in_cksum((u_short *)up, len, sum);
 }
+#endif
 
 
 
@@ -556,13 +570,26 @@ udp_print(register const u_char *bp, u_int length, register const u_char *bp2)
 		if (sum == 0) {
 			(void)printf(" [no cksum]");
 		} else if (TTEST2(cp[0], length)) {
-			sum = udp_cksum(ip, up, length);
+			sum = udp_cksum(ip, up, length + sizeof(struct udphdr));
+			if (sum != 0)
+				(void)printf(" [bad udp cksum %x!]", sum);
+			else
+				(void)printf(" [udp sum ok]");
+		}
+	}
+#ifdef INET6
+	if (ip->ip_v == 6 && ip6->ip6_plen && vflag) {
+		int sum = up->uh_sum;
+		/* for IPv6, UDP checksum is mandatory */
+		if (TTEST2(cp[0], length)) {
+			sum = udp6_cksum(ip6, up, length + sizeof(struct udphdr));
 			if (sum != 0)
 				(void)printf(" [bad udp cksum %x!]", sum);
 			else
 				(void)printf(" [udp sum ok]");
 		}
 	}
+#endif
 
 	if (!qflag) {
 #define ISPORT(p) (dport == (p) || sport == (p))