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Commit ac8a4810 authored by Li Wei's avatar Li Wei Committed by David S. Miller
Browse files

ipv4: Save nexthop address of LSRR/SSRR option to IPCB. 



We can not update iph->daddr in ip_options_rcv_srr(), It is too early.
When some exception ocurred later (eg. in ip_forward() when goto
sr_failed) we need the ip header be identical to the original one as
ICMP need it.

Add a field 'nexthop' in struct ip_options to save nexthop of LSRR
or SSRR option.

Signed-off-by: default avatarLi Wei <lw@cn.fujitsu.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 67c170a2

include/net/inet_sock.h

+2 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
/** struct ip_options - IP Options

 *

 * @faddr - Saved first hop address

 * @nexthop - Saved nexthop address in LSRR and SSRR

 * @is_data - Options in __data, rather than skb

 * @is_strictroute - Strict source route

 * @srr_is_hit - Packet destination addr was our one
@@ -41,6 +42,7 @@ 
 */

struct ip_options {

	__be32		faddr;

	__be32		nexthop;

	unsigned char	optlen;

	unsigned char	srr;

	unsigned char	rr;

net/ipv4/ip_forward.c

+1 −1
Original line number Diff line number Diff line
@@ -84,7 +84,7 @@ int ip_forward(struct sk_buff *skb) 


	rt = skb_rtable(skb);



	if (opt->is_strictroute && ip_hdr(skb)->daddr != rt->rt_gateway)

	if (opt->is_strictroute && opt->nexthop != rt->rt_gateway)

		goto sr_failed;



	if (unlikely(skb->len > dst_mtu(&rt->dst) && !skb_is_gso(skb) &&

net/ipv4/ip_options.c

+3 −2
Original line number Diff line number Diff line
@@ -568,12 +568,13 @@ void ip_forward_options(struct sk_buff *skb) 
		     ) {

			if (srrptr + 3 > srrspace)

				break;

			if (memcmp(&ip_hdr(skb)->daddr, &optptr[srrptr-1], 4) == 0)

			if (memcmp(&opt->nexthop, &optptr[srrptr-1], 4) == 0)

				break;

		}

		if (srrptr + 3 <= srrspace) {

			opt->is_changed = 1;

			ip_rt_get_source(&optptr[srrptr-1], skb, rt);

			ip_hdr(skb)->daddr = opt->nexthop;

			optptr[2] = srrptr+4;

		} else if (net_ratelimit())

			printk(KERN_CRIT "ip_forward(): Argh! Destination lost!\n");
@@ -640,7 +641,7 @@ int ip_options_rcv_srr(struct sk_buff *skb) 
	}

	if (srrptr <= srrspace) {

		opt->srr_is_hit = 1;

		iph->daddr = nexthop;

		opt->nexthop = nexthop;

		opt->is_changed = 1;

	}

	return 0;