remove assumption on mbuf pointed to by m0; sync w/kame

1 files changed, 48 insertions, 64 deletions

diff --git a/sys/netinet6/icmp6.c b/sys/netinet6/icmp6.c
index 267a5509a78..1800667847c 100644
--- a/sys/netinet6/icmp6.c
+++ b/sys/netinet6/icmp6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: icmp6.c,v 1.69 2003/06/02 23:28:15 millert Exp $	*/
+/*	$OpenBSD: icmp6.c,v 1.70 2003/06/03 06:25:26 itojun Exp $	*/
 /*	$KAME: icmp6.c,v 1.217 2001/06/20 15:03:29 jinmei Exp $	*/
 
 /*
@@ -2554,77 +2554,61 @@ icmp6_redirect_output(m0, rt)
 	if (p - (u_char *)ip6 > maxlen)
 		goto noredhdropt;
 
-    {
-	/* redirected header option */
-	int len;
-	struct nd_opt_rd_hdr *nd_opt_rh;
+	{
+		/* redirected header option */
+		int len;
+		struct nd_opt_rd_hdr *nd_opt_rh;
 
-	/*
-	 * compute the maximum size for icmp6 redirect header option.
-	 * XXX room for auth header?
-	 */
-	len = maxlen - (p - (u_char *)ip6);
-	len &= ~7;
-
-	/* This is just for simplicity. */
-	if (m0->m_pkthdr.len != m0->m_len) {
-		if (m0->m_next) {
-			m_freem(m0->m_next);
-			m0->m_next = NULL;
-		}
-		m0->m_pkthdr.len = m0->m_len;
-	}
+		/*
+		 * compute the maximum size for icmp6 redirect header option.
+		 * XXX room for auth header?
+		 */
+		len = maxlen - (p - (u_char *)ip6);
+		len &= ~7;
 
-	/*
-	 * Redirected header option spec (RFC2461 4.6.3) talks nothing
-	 * about padding/truncate rule for the original IP packet.
-	 * From the discussion on IPv6imp in Feb 1999, the consensus was:
-	 * - "attach as much as possible" is the goal
-	 * - pad if not aligned (original size can be guessed by original
-	 *   ip6 header)
-	 * Following code adds the padding if it is simple enough,
-	 * and truncates if not.
-	 */
-	if (m0->m_next || m0->m_pkthdr.len != m0->m_len)
-		panic("assumption failed in %s:%d", __FILE__, __LINE__);
+		/*
+		 * Redirected header option spec (RFC2461 4.6.3) talks nothing
+		 * about padding/truncate rule for the original IP packet.
+		 * From the discussion on IPv6imp in Feb 1999,
+		 * the consensus was:
+		 * - "attach as much as possible" is the goal
+		 * - pad if not aligned (original size can be guessed by
+		 *   original ip6 header)
+		 * Following code adds the padding if it is simple enough,
+		 * and truncates if not.
+		 */
+		if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
+			/* not enough room, truncate */
+			m_adj(m0, (len - sizeof(*nd_opt_rh)) -
+			    m0->m_pkthdr.len);
+		} else {
+			/*
+			 * enough room, truncate if not aligned.
+			 * we don't pad here for simplicity.
+			 */
+			size_t extra;
 
-	if (len - sizeof(*nd_opt_rh) < m0->m_pkthdr.len) {
-		/* not enough room, truncate */
-		m0->m_pkthdr.len = m0->m_len = len - sizeof(*nd_opt_rh);
-	} else {
-		/* enough room, pad or truncate */
-		size_t extra;
-
-		extra = m0->m_pkthdr.len % 8;
-		if (extra) {
-			/* pad if easy enough, truncate if not */
-			if (8 - extra <= M_TRAILINGSPACE(m0)) {
-				/* pad */
-				m0->m_len += (8 - extra);
-				m0->m_pkthdr.len += (8 - extra);
-			} else {
+			extra = m0->m_pkthdr.len % 8;
+			if (extra) {
 				/* truncate */
-				m0->m_pkthdr.len -= extra;
-				m0->m_len -= extra;
+				m_adj(m0, -extra);
 			}
+			len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
 		}
-		len = m0->m_pkthdr.len + sizeof(*nd_opt_rh);
-		m0->m_pkthdr.len = m0->m_len = len - sizeof(*nd_opt_rh);
-	}
 
-	nd_opt_rh = (struct nd_opt_rd_hdr *)p;
-	bzero(nd_opt_rh, sizeof(*nd_opt_rh));
-	nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
-	nd_opt_rh->nd_opt_rh_len = len >> 3;
-	p += sizeof(*nd_opt_rh);
-	m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
+		nd_opt_rh = (struct nd_opt_rd_hdr *)p;
+		bzero(nd_opt_rh, sizeof(*nd_opt_rh));
+		nd_opt_rh->nd_opt_rh_type = ND_OPT_REDIRECTED_HEADER;
+		nd_opt_rh->nd_opt_rh_len = len >> 3;
+		p += sizeof(*nd_opt_rh);
+		m->m_pkthdr.len = m->m_len = p - (u_char *)ip6;
 
-	/* connect m0 to m */
-	m->m_next = m0;
-	m->m_pkthdr.len = m->m_len + m0->m_len;
-	m0 = NULL;
-    }
-noredhdropt:;
+		/* connect m0 to m */
+		m_cat(m, m0);
+		m->m_pkthdr.len += m0->m_pkthdr.len;
+		m0 = NULL;
+	}
+noredhdropt:
 	if (m0) {
 		m_freem(m0);
 		m0 = NULL;