Cleanup the UDP decapsulation code.

MFC after: 3 days

1 files changed, 20 insertions, 42 deletions

diff --git a/sys/netinet/sctputil.c b/sys/netinet/sctputil.c
index 8fa6826..0cdd632 100644
--- a/sys/netinet/sctputil.c
+++ b/sys/netinet/sctputil.c
@@ -6837,83 +6837,61 @@ sctp_recv_udp_tunneled_packet(struct mbuf *m, int off, struct inpcb *ignored)
 	struct ip *iph;
 	struct mbuf *sp, *last;
 	struct udphdr *uhdr;
-	uint16_t port = 0;
-	int header_size = sizeof(struct udphdr) + sizeof(struct sctphdr);
+	uint16_t port;
 
-	/*
-	 * Split out the mbuf chain. Leave the IP header in m, place the
-	 * rest in the sp.
-	 */
 	if ((m->m_flags & M_PKTHDR) == 0) {
 		/* Can't handle one that is not a pkt hdr */
 		goto out;
 	}
-	/* pull the src port */
+	/* Pull the src port */
 	iph = mtod(m, struct ip *);
 	uhdr = (struct udphdr *)((caddr_t)iph + off);
-
 	port = uhdr->uh_sport;
+	/*
+	 * Split out the mbuf chain. Leave the IP header in m, place the
+	 * rest in the sp.
+	 */
 	sp = m_split(m, off, M_DONTWAIT);
 	if (sp == NULL) {
 		/* Gak, drop packet, we can't do a split */
 		goto out;
 	}
-	if (sp->m_pkthdr.len < header_size) {
-		/* Gak, packet can't have an SCTP header in it - to small */
+	if (sp->m_pkthdr.len < sizeof(struct udphdr) + sizeof(struct sctphdr)) {
+		/* Gak, packet can't have an SCTP header in it - too small */
 		m_freem(sp);
 		goto out;
 	}
-	/* ok now pull up the UDP header and SCTP header together */
-	sp = m_pullup(sp, header_size);
+	/* Now pull up the UDP header and SCTP header together */
+	sp = m_pullup(sp, sizeof(struct udphdr) + sizeof(struct sctphdr));
 	if (sp == NULL) {
 		/* Gak pullup failed */
 		goto out;
 	}
-	/* trim out the UDP header */
+	/* Trim out the UDP header */
 	m_adj(sp, sizeof(struct udphdr));
 
 	/* Now reconstruct the mbuf chain */
-	/* 1) find last one */
-	last = m;
-	while (last->m_next != NULL) {
-		last = last->m_next;
-	}
+	for (last = m; last->m_next; last = last->m_next);
 	last->m_next = sp;
 	m->m_pkthdr.len += sp->m_pkthdr.len;
-	last = m;
-	while (last != NULL) {
-		last = last->m_next;
-	}
-	/* Now its ready for sctp_input or sctp6_input */
 	iph = mtod(m, struct ip *);
 	switch (iph->ip_v) {
 #ifdef INET
 	case IPVERSION:
-		{
-			uint16_t len;
-
-			/* its IPv4 */
-			len = SCTP_GET_IPV4_LENGTH(iph);
-			len -= sizeof(struct udphdr);
-			SCTP_GET_IPV4_LENGTH(iph) = len;
-			sctp_input_with_port(m, off, port);
-			break;
-		}
+		iph->ip_len -= sizeof(struct udphdr);
+		sctp_input_with_port(m, off, port);
+		break;
 #endif
 #ifdef INET6
 	case IPV6_VERSION >> 4:
-		{
-			/* its IPv6 - NOT supported */
-			goto out;
-			break;
+		/* Not yet supported. */
+		goto out;
+		break;
 
-		}
 #endif
 	default:
-		{
-			m_freem(m);
-			break;
-		}
+		goto out;
+		break;
 	}
 	return;
 out: