IPVS: make FTP work with full NAT support

Use nf_conntrack/nf_nat code to do the packet mangling and the TCP
sequence adjusting.  The function 'ip_vs_skb_replace' is now dead
code, so it is removed.

To SNAT FTP, use something like:

% iptables -t nat -A POSTROUTING -m ipvs --vaddr 192.168.100.30/32 \
    --vport 21 -j SNAT --to-source 192.168.10.10
and for the data connections in passive mode:

% iptables -t nat -A POSTROUTING -m ipvs --vaddr 192.168.100.30/32 \
    --vportctl 21 -j SNAT --to-source 192.168.10.10
using '-m state --state RELATED' would also works.

Make sure the kernel modules ip_vs_ftp, nf_conntrack_ftp, and
nf_nat_ftp are loaded.

[ up-port and minor fixes by Simon Horman <horms@verge.net.au> ]
Signed-off-by: Hannes Eder <heder@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 0 insertions, 43 deletions

diff --git a/net/netfilter/ipvs/ip_vs_app.c b/net/netfilter/ipvs/ip_vs_app.c
index 1cb0e83..e76f87f 100644
--- a/net/netfilter/ipvs/ip_vs_app.c
+++ b/net/netfilter/ipvs/ip_vs_app.c
@@ -569,49 +569,6 @@ static const struct file_operations ip_vs_app_fops = {
 };
 #endif
 
-
-/*
- *	Replace a segment of data with a new segment
- */
-int ip_vs_skb_replace(struct sk_buff *skb, gfp_t pri,
-		      char *o_buf, int o_len, char *n_buf, int n_len)
-{
-	int diff;
-	int o_offset;
-	int o_left;
-
-	EnterFunction(9);
-
-	diff = n_len - o_len;
-	o_offset = o_buf - (char *)skb->data;
-	/* The length of left data after o_buf+o_len in the skb data */
-	o_left = skb->len - (o_offset + o_len);
-
-	if (diff <= 0) {
-		memmove(o_buf + n_len, o_buf + o_len, o_left);
-		memcpy(o_buf, n_buf, n_len);
-		skb_trim(skb, skb->len + diff);
-	} else if (diff <= skb_tailroom(skb)) {
-		skb_put(skb, diff);
-		memmove(o_buf + n_len, o_buf + o_len, o_left);
-		memcpy(o_buf, n_buf, n_len);
-	} else {
-		if (pskb_expand_head(skb, skb_headroom(skb), diff, pri))
-			return -ENOMEM;
-		skb_put(skb, diff);
-		memmove(skb->data + o_offset + n_len,
-			skb->data + o_offset + o_len, o_left);
-		skb_copy_to_linear_data_offset(skb, o_offset, n_buf, n_len);
-	}
-
-	/* must update the iph total length here */
-	ip_hdr(skb)->tot_len = htons(skb->len);
-
-	LeaveFunction(9);
-	return 0;
-}
-
-
 int __init ip_vs_app_init(void)
 {
 	/* we will replace it with proc_net_ipvs_create() soon */