[src/trunk]: src/usr.sbin/tcpdump implement tcp6 pseudo header cksum.

[itojun <itojun%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/58ead8e1649e
branches:  trunk
changeset: 495607:58ead8e1649e
user:      itojun <itojun%NetBSD.org@localhost>
date:      Tue Aug 01 17:24:40 2000 +0000

description:
implement tcp6 pseudo header cksum.

diffstat:

 usr.sbin/tcpdump/print-tcp.c |  64 ++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 62 insertions(+), 2 deletions(-)

diffs (92 lines):

diff -r 4cbbab2801d9 -r 58ead8e1649e usr.sbin/tcpdump/print-tcp.c
--- a/usr.sbin/tcpdump/print-tcp.c      Tue Aug 01 16:49:47 2000 +0000
+++ b/usr.sbin/tcpdump/print-tcp.c      Tue Aug 01 17:24:40 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: print-tcp.c,v 1.16 1999/12/10 05:45:08 itojun Exp $    */
+/*     $NetBSD: print-tcp.c,v 1.17 2000/08/01 17:24:40 itojun Exp $    */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
@@ -27,7 +27,7 @@
 static const char rcsid[] =
     "@(#) Header: print-tcp.c,v 1.55 97/06/15 13:20:28 leres Exp  (LBL)";
 #else
-__RCSID("$NetBSD: print-tcp.c,v 1.16 1999/12/10 05:45:08 itojun Exp $");
+__RCSID("$NetBSD: print-tcp.c,v 1.17 2000/08/01 17:24:40 itojun Exp $");
 #endif
 #endif
 
@@ -159,6 +159,54 @@
        return (sum);
 }
 
+#ifdef INET6
+static int tcp6_cksum(const struct ip6_hdr *ip6, const struct tcphdr *tp,
+       int len)
+{
+       int i, tlen;
+       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;
+
+       tlen = ntohs(ip6->ip6_plen) + sizeof(struct ip6_hdr) -
+           ((const char *)tp - (const char*)ip6);
+
+       /* 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(tlen);
+       phu.ph.ph_nxt = IPPROTO_TCP;
+
+       sum = 0;
+       for (i = 0; i < sizeof(phu.pa) / sizeof(phu.pa[0]); i++)
+               sum += phu.pa[i];
+
+       sp = (const u_int16_t *)tp;
+
+       for (i = 0; i < (tlen & ~1); i += 2)
+               sum += *sp++;
+
+       if (tlen & 1)
+               sum += htons((*(const char *)sp) << 8);
+
+       while (sum > 0xffff)
+               sum = (sum & 0xffff) + (sum >> 16);
+       sum = ~sum & 0xffff;
+
+       return (sum);
+}
+#endif
+
 
 void
 tcp_print(register const u_char *bp, register u_int length,
@@ -379,6 +427,18 @@
                                (void)printf(" [tcp sum ok]");
                }
        }
+#ifdef INET6
+       if (ip->ip_v == 6 && 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
 
        length -= hlen;
        if (length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))