[IPV6] use macro for maximum payload length

include/net/ipv6.h

@@ -23,6 +23,8 @@
 
 #define SIN6_LEN_RFC2133	24
 
+#define IPV6_MAXPLEN		65535
+
 /*
  *	NextHeader field of IPv6 header
  */

net/ipv6/exthdrs.c

@@ -432,7 +432,7 @@ static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 	}
 
 	pkt_len = ntohl(*(u32*)(skb->nh.raw+optoff+2));
-	if (pkt_len < 0x10000) {
+	if (pkt_len <= IPV6_MAXPLEN) {
 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 		return 0;
 	}

net/ipv6/ip6_output.c

@@ -621,7 +621,7 @@ int ip6_build_xmit(struct sock *sk, inet_getfrag_t getfrag, const void *data,
 		if (opt)
 			pktlength += opt->opt_flen + opt->opt_nflen;
 
-		if (pktlength > 0xFFFF + sizeof(struct ipv6hdr)) {
+		if (pktlength > sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
 			/* Jumbo datagram.
 			   It is assumed, that in the case of hdrincl
 			   jumbo option is supplied by user.
@@ -1264,8 +1264,8 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, int offse
 	fragheaderlen = sizeof(struct ipv6hdr) + (opt ? opt->opt_nflen : 0);
 	maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
 
-	if (mtu < 65576) {
-		if (inet->cork.length + length > 0xFFFF - fragheaderlen) {
+	if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
+		if (inet->cork.length + length > IPV6_MAXPLEN - fragheaderlen) {
 			ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen);
 			return -EMSGSIZE;
 		}
@@ -1461,7 +1461,7 @@ int ip6_push_pending_frames(struct sock *sk)
 	
 	*(u32*)hdr = fl->fl6_flowlabel | htonl(0x60000000);
 
-	if (skb->len < 65536)
+	if (skb->len <= IPV6_MAXPLEN)
 		hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 	else
 		hdr->payload_len = 0;

net/ipv6/reassembly.c

@@ -425,7 +425,7 @@ static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 	end = offset + (ntohs(skb->nh.ipv6h->payload_len) -
 			((u8 *) (fhdr + 1) - (u8 *) (skb->nh.ipv6h + 1)));
 
-	if ((unsigned int)end >= 65536) {
+	if ((unsigned int)end > IPV6_MAXPLEN) {
  		icmpv6_param_prob(skb,ICMPV6_HDR_FIELD, (u8*)&fhdr->frag_off - skb->nh.raw);
  		return;
 	}
@@ -597,7 +597,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in,
 
 	/* Unfragmented part is taken from the first segment. */
 	payload_len = (head->data - head->nh.raw) - sizeof(struct ipv6hdr) + fq->len - sizeof(struct frag_hdr);
-	if (payload_len > 65535)
+	if (payload_len > IPV6_MAXPLEN)
 		goto out_oversize;
 
 	/* Head of list must not be cloned. */

net/ipv6/route.c

@@ -606,13 +606,13 @@ static inline unsigned int ipv6_advmss(unsigned int mtu)
 		mtu = ip6_rt_min_advmss;
 
 	/*
-	 * Maximal non-jumbo IPv6 payload is 65535 and 
-	 * corresponding MSS is 65535 - tcp_header_size. 
-	 * 65535 is also valid and means: "any MSS, 
+	 * Maximal non-jumbo IPv6 payload is IPV6_MAXPLEN and 
+	 * corresponding MSS is IPV6_MAXPLEN - tcp_header_size. 
+	 * IPV6_MAXPLEN is also valid and means: "any MSS, 
 	 * rely only on pmtu discovery"
 	 */
-	if (mtu > 65535 - sizeof(struct tcphdr))
-		mtu = 65535;
+	if (mtu > IPV6_MAXPLEN - sizeof(struct tcphdr))
+		mtu = IPV6_MAXPLEN;
 	return mtu;
 }