1 files changed, 187 insertions, 122 deletions

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 8c9189a41b13..d8f2a22c6ff7 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -525,9 +525,6 @@ static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
 
 	skb_copy_hash(to, from);
 
-	/* Copy the flags to each fragment. */
-	IPCB(to)->flags = IPCB(from)->flags;
-
 #ifdef CONFIG_NET_SCHED
 	to->tc_index = from->tc_index;
 #endif
@@ -561,6 +558,176 @@ static int ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 	return ip_do_fragment(net, sk, skb, output);
 }
 
+void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,
+		      unsigned int hlen, struct ip_fraglist_iter *iter)
+{
+	unsigned int first_len = skb_pagelen(skb);
+
+	iter->frag_list = skb_shinfo(skb)->frag_list;
+	iter->frag = iter->frag_list;
+	skb_frag_list_init(skb);
+
+	iter->offset = 0;
+	iter->iph = iph;
+	iter->hlen = hlen;
+
+	skb->data_len = first_len - skb_headlen(skb);
+	skb->len = first_len;
+	iph->tot_len = htons(first_len);
+	iph->frag_off = htons(IP_MF);
+	ip_send_check(iph);
+}
+EXPORT_SYMBOL(ip_fraglist_init);
+
+static void ip_fraglist_ipcb_prepare(struct sk_buff *skb,
+				     struct ip_fraglist_iter *iter)
+{
+	struct sk_buff *to = iter->frag;
+
+	/* Copy the flags to each fragment. */
+	IPCB(to)->flags = IPCB(skb)->flags;
+
+	if (iter->offset == 0)
+		ip_options_fragment(to);
+}
+
+void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter)
+{
+	unsigned int hlen = iter->hlen;
+	struct iphdr *iph = iter->iph;
+	struct sk_buff *frag;
+
+	frag = iter->frag;
+	frag->ip_summed = CHECKSUM_NONE;
+	skb_reset_transport_header(frag);
+	__skb_push(frag, hlen);
+	skb_reset_network_header(frag);
+	memcpy(skb_network_header(frag), iph, hlen);
+	iter->iph = ip_hdr(frag);
+	iph = iter->iph;
+	iph->tot_len = htons(frag->len);
+	ip_copy_metadata(frag, skb);
+	iter->offset += skb->len - hlen;
+	iph->frag_off = htons(iter->offset >> 3);
+	if (frag->next)
+		iph->frag_off |= htons(IP_MF);
+	/* Ready, complete checksum */
+	ip_send_check(iph);
+}
+EXPORT_SYMBOL(ip_fraglist_prepare);
+
+void ip_frag_init(struct sk_buff *skb, unsigned int hlen,
+		  unsigned int ll_rs, unsigned int mtu,
+		  struct ip_frag_state *state)
+{
+	struct iphdr *iph = ip_hdr(skb);
+
+	state->hlen = hlen;
+	state->ll_rs = ll_rs;
+	state->mtu = mtu;
+
+	state->left = skb->len - hlen;	/* Space per frame */
+	state->ptr = hlen;		/* Where to start from */
+
+	state->offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
+	state->not_last_frag = iph->frag_off & htons(IP_MF);
+}
+EXPORT_SYMBOL(ip_frag_init);
+
+static void ip_frag_ipcb(struct sk_buff *from, struct sk_buff *to,
+			 bool first_frag, struct ip_frag_state *state)
+{
+	/* Copy the flags to each fragment. */
+	IPCB(to)->flags = IPCB(from)->flags;
+
+	if (IPCB(from)->flags & IPSKB_FRAG_PMTU)
+		state->iph->frag_off |= htons(IP_DF);
+
+	/* ANK: dirty, but effective trick. Upgrade options only if
+	 * the segment to be fragmented was THE FIRST (otherwise,
+	 * options are already fixed) and make it ONCE
+	 * on the initial skb, so that all the following fragments
+	 * will inherit fixed options.
+	 */
+	if (first_frag)
+		ip_options_fragment(from);
+}
+
+struct sk_buff *ip_frag_next(struct sk_buff *skb, struct ip_frag_state *state)
+{
+	unsigned int len = state->left;
+	struct sk_buff *skb2;
+	struct iphdr *iph;
+
+	len = state->left;
+	/* IF: it doesn't fit, use 'mtu' - the data space left */
+	if (len > state->mtu)
+		len = state->mtu;
+	/* IF: we are not sending up to and including the packet end
+	   then align the next start on an eight byte boundary */
+	if (len < state->left)	{
+		len &= ~7;
+	}
+
+	/* Allocate buffer */
+	skb2 = alloc_skb(len + state->hlen + state->ll_rs, GFP_ATOMIC);
+	if (!skb2)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 *	Set up data on packet
+	 */
+
+	ip_copy_metadata(skb2, skb);
+	skb_reserve(skb2, state->ll_rs);
+	skb_put(skb2, len + state->hlen);
+	skb_reset_network_header(skb2);
+	skb2->transport_header = skb2->network_header + state->hlen;
+
+	/*
+	 *	Charge the memory for the fragment to any owner
+	 *	it might possess
+	 */
+
+	if (skb->sk)
+		skb_set_owner_w(skb2, skb->sk);
+
+	/*
+	 *	Copy the packet header into the new buffer.
+	 */
+
+	skb_copy_from_linear_data(skb, skb_network_header(skb2), state->hlen);
+
+	/*
+	 *	Copy a block of the IP datagram.
+	 */
+	if (skb_copy_bits(skb, state->ptr, skb_transport_header(skb2), len))
+		BUG();
+	state->left -= len;
+
+	/*
+	 *	Fill in the new header fields.
+	 */
+	iph = ip_hdr(skb2);
+	iph->frag_off = htons((state->offset >> 3));
+
+	/*
+	 *	Added AC : If we are fragmenting a fragment that's not the
+	 *		   last fragment then keep MF on each bit
+	 */
+	if (state->left > 0 || state->not_last_frag)
+		iph->frag_off |= htons(IP_MF);
+	state->ptr += len;
+	state->offset += len;
+
+	iph->tot_len = htons(len + state->hlen);
+
+	ip_send_check(iph);
+
+	return skb2;
+}
+EXPORT_SYMBOL(ip_frag_next);
+
 /*
  *	This IP datagram is too large to be sent in one piece.  Break it up into
  *	smaller pieces (each of size equal to IP header plus
@@ -572,12 +739,11 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 		   int (*output)(struct net *, struct sock *, struct sk_buff *))
 {
 	struct iphdr *iph;
-	int ptr;
 	struct sk_buff *skb2;
-	unsigned int mtu, hlen, left, len, ll_rs;
-	int offset;
-	__be16 not_last_frag;
 	struct rtable *rt = skb_rtable(skb);
+	unsigned int mtu, hlen, ll_rs;
+	struct ip_fraglist_iter iter;
+	struct ip_frag_state state;
 	int err = 0;
 
 	/* for offloaded checksums cleanup checksum before fragmentation */
@@ -642,49 +808,24 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 		}
 
 		/* Everything is OK. Generate! */
-
-		err = 0;
-		offset = 0;
-		frag = skb_shinfo(skb)->frag_list;
-		skb_frag_list_init(skb);
-		skb->data_len = first_len - skb_headlen(skb);
-		skb->len = first_len;
-		iph->tot_len = htons(first_len);
-		iph->frag_off = htons(IP_MF);
-		ip_send_check(iph);
+		ip_fraglist_init(skb, iph, hlen, &iter);
 
 		for (;;) {
 			/* Prepare header of the next frame,
 			 * before previous one went down. */
-			if (frag) {
-				frag->ip_summed = CHECKSUM_NONE;
-				skb_reset_transport_header(frag);
-				__skb_push(frag, hlen);
-				skb_reset_network_header(frag);
-				memcpy(skb_network_header(frag), iph, hlen);
-				iph = ip_hdr(frag);
-				iph->tot_len = htons(frag->len);
-				ip_copy_metadata(frag, skb);
-				if (offset == 0)
-					ip_options_fragment(frag);
-				offset += skb->len - hlen;
-				iph->frag_off = htons(offset>>3);
-				if (frag->next)
-					iph->frag_off |= htons(IP_MF);
-				/* Ready, complete checksum */
-				ip_send_check(iph);
+			if (iter.frag) {
+				ip_fraglist_ipcb_prepare(skb, &iter);
+				ip_fraglist_prepare(skb, &iter);
 			}
 
 			err = output(net, sk, skb);
 
 			if (!err)
 				IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES);
-			if (err || !frag)
+			if (err || !iter.frag)
 				break;
 
-			skb = frag;
-			frag = skb->next;
-			skb_mark_not_on_list(skb);
+			skb = ip_fraglist_next(&iter);
 		}
 
 		if (err == 0) {
@@ -692,7 +833,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 			return 0;
 		}
 
-		kfree_skb_list(frag);
+		kfree_skb_list(iter.frag_list);
 
 		IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
 		return err;
@@ -708,105 +849,29 @@ slow_path_clean:
 	}
 
 slow_path:
-	iph = ip_hdr(skb);
-
-	left = skb->len - hlen;		/* Space per frame */
-	ptr = hlen;		/* Where to start from */
-
 	/*
 	 *	Fragment the datagram.
 	 */
 
-	offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
-	not_last_frag = iph->frag_off & htons(IP_MF);
+	ip_frag_init(skb, hlen, ll_rs, mtu, &state);
 
 	/*
 	 *	Keep copying data until we run out.
 	 */
 
-	while (left > 0) {
-		len = left;
-		/* IF: it doesn't fit, use 'mtu' - the data space left */
-		if (len > mtu)
-			len = mtu;
-		/* IF: we are not sending up to and including the packet end
-		   then align the next start on an eight byte boundary */
-		if (len < left)	{
-			len &= ~7;
-		}
+	while (state.left > 0) {
+		bool first_frag = (state.offset == 0);
 
-		/* Allocate buffer */
-		skb2 = alloc_skb(len + hlen + ll_rs, GFP_ATOMIC);
-		if (!skb2) {
-			err = -ENOMEM;
+		skb2 = ip_frag_next(skb, &state);
+		if (IS_ERR(skb2)) {
+			err = PTR_ERR(skb2);
 			goto fail;
 		}
-
-		/*
-		 *	Set up data on packet
-		 */
-
-		ip_copy_metadata(skb2, skb);
-		skb_reserve(skb2, ll_rs);
-		skb_put(skb2, len + hlen);
-		skb_reset_network_header(skb2);
-		skb2->transport_header = skb2->network_header + hlen;
-
-		/*
-		 *	Charge the memory for the fragment to any owner
-		 *	it might possess
-		 */
-
-		if (skb->sk)
-			skb_set_owner_w(skb2, skb->sk);
-
-		/*
-		 *	Copy the packet header into the new buffer.
-		 */
-
-		skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen);
-
-		/*
-		 *	Copy a block of the IP datagram.
-		 */
-		if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len))
-			BUG();
-		left -= len;
-
-		/*
-		 *	Fill in the new header fields.
-		 */
-		iph = ip_hdr(skb2);
-		iph->frag_off = htons((offset >> 3));
-
-		if (IPCB(skb)->flags & IPSKB_FRAG_PMTU)
-			iph->frag_off |= htons(IP_DF);
-
-		/* ANK: dirty, but effective trick. Upgrade options only if
-		 * the segment to be fragmented was THE FIRST (otherwise,
-		 * options are already fixed) and make it ONCE
-		 * on the initial skb, so that all the following fragments
-		 * will inherit fixed options.
-		 */
-		if (offset == 0)
-			ip_options_fragment(skb);
-
-		/*
-		 *	Added AC : If we are fragmenting a fragment that's not the
-		 *		   last fragment then keep MF on each bit
-		 */
-		if (left > 0 || not_last_frag)
-			iph->frag_off |= htons(IP_MF);
-		ptr += len;
-		offset += len;
+		ip_frag_ipcb(skb, skb2, first_frag, &state);
 
 		/*
 		 *	Put this fragment into the sending queue.
 		 */
-		iph->tot_len = htons(len + hlen);
-
-		ip_send_check(iph);
-
 		err = output(net, sk, skb2);
 		if (err)
 			goto fail;