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authorAndy Zhou <azhou@nicira.com>2015-05-15 14:15:37 -0700
committerDavid S. Miller <davem@davemloft.net>2015-05-19 00:15:39 -0400
commit49d16b23cd1e61c028ee088c5a64e9ac6a9c6147 (patch)
tree446c416b396c4561bd5616f6fba2ef52c43c8d06
parent8bc04864ac89616e55fc8a196dd32b7066433ea8 (diff)
bridge_netfilter: No ICMP packet on IPv4 fragmentation error
When bridge netfilter re-fragments an IP packet for output, all packets that can not be re-fragmented to their original input size should be silently discarded. However, current bridge netfilter output path generates an ICMP packet with 'size exceeded MTU' message for such packets, this is a bug. This patch refactors the ip_fragment() API to allow two separate use cases. The bridge netfilter user case will not send ICMP, the routing output will, as before. Signed-off-by: Andy Zhou <azhou@nicira.com> Acked-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/ip.h4
-rw-r--r--net/bridge/br_netfilter.c21
-rw-r--r--net/ipv4/ip_output.c40
3 files changed, 50 insertions, 15 deletions
diff --git a/include/net/ip.h b/include/net/ip.h
index 43f6f39df9fc..cd7a6a458bb6 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -108,8 +108,8 @@ int ip_local_deliver(struct sk_buff *skb);
int ip_mr_input(struct sk_buff *skb);
int ip_output(struct sock *sk, struct sk_buff *skb);
int ip_mc_output(struct sock *sk, struct sk_buff *skb);
-int ip_fragment(struct sock *sk, struct sk_buff *skb,
- int (*output)(struct sock *, struct sk_buff *));
+int ip_do_fragment(struct sock *sk, struct sk_buff *skb,
+ int (*output)(struct sock *, struct sk_buff *));
int ip_do_nat(struct sk_buff *skb);
void ip_send_check(struct iphdr *ip);
int __ip_local_out(struct sk_buff *skb);
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 2b0e8bb49944..1d2eb32d8270 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -853,6 +853,25 @@ static int br_nf_push_frag_xmit(struct sock *sk, struct sk_buff *skb)
return br_dev_queue_push_xmit(sk, skb);
}
+static int br_nf_ip_fragment(struct sock *sk, struct sk_buff *skb,
+ int (*output)(struct sock *, struct sk_buff *))
+{
+ unsigned int mtu = ip_skb_dst_mtu(skb);
+ struct iphdr *iph = ip_hdr(skb);
+ struct rtable *rt = skb_rtable(skb);
+ struct net_device *dev = rt->dst.dev;
+
+ if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
+ (IPCB(skb)->frag_max_size &&
+ IPCB(skb)->frag_max_size > mtu))) {
+ IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
+ kfree_skb(skb);
+ return -EMSGSIZE;
+ }
+
+ return ip_do_fragment(sk, skb, output);
+}
+
static int br_nf_dev_queue_xmit(struct sock *sk, struct sk_buff *skb)
{
int ret;
@@ -886,7 +905,7 @@ static int br_nf_dev_queue_xmit(struct sock *sk, struct sk_buff *skb)
skb_copy_from_linear_data_offset(skb, -data->size, data->mac,
data->size);
- ret = ip_fragment(sk, skb, br_nf_push_frag_xmit);
+ ret = br_nf_ip_fragment(sk, skb, br_nf_push_frag_xmit);
} else {
nf_bridge_info_free(skb);
ret = br_dev_queue_push_xmit(sk, skb);
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 2acc5dc32807..8d91b922fcfe 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -83,6 +83,9 @@
int sysctl_ip_default_ttl __read_mostly = IPDEFTTL;
EXPORT_SYMBOL(sysctl_ip_default_ttl);
+static int ip_fragment(struct sock *sk, struct sk_buff *skb,
+ int (*output)(struct sock *, struct sk_buff *));
+
/* Generate a checksum for an outgoing IP datagram. */
void ip_send_check(struct iphdr *iph)
{
@@ -478,6 +481,28 @@ static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
skb_copy_secmark(to, from);
}
+static int ip_fragment(struct sock *sk, struct sk_buff *skb,
+ int (*output)(struct sock *, struct sk_buff *))
+{
+ struct iphdr *iph = ip_hdr(skb);
+ unsigned int mtu = ip_skb_dst_mtu(skb);
+
+ if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
+ (IPCB(skb)->frag_max_size &&
+ IPCB(skb)->frag_max_size > mtu))) {
+ struct rtable *rt = skb_rtable(skb);
+ struct net_device *dev = rt->dst.dev;
+
+ IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+ htonl(mtu));
+ kfree_skb(skb);
+ return -EMSGSIZE;
+ }
+
+ return ip_do_fragment(sk, skb, output);
+}
+
/*
* 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
@@ -485,8 +510,8 @@ static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
* single device frame, and queue such a frame for sending.
*/
-int ip_fragment(struct sock *sk, struct sk_buff *skb,
- int (*output)(struct sock *, struct sk_buff *))
+int ip_do_fragment(struct sock *sk, struct sk_buff *skb,
+ int (*output)(struct sock *, struct sk_buff *))
{
struct iphdr *iph;
int ptr;
@@ -507,15 +532,6 @@ int ip_fragment(struct sock *sk, struct sk_buff *skb,
iph = ip_hdr(skb);
mtu = ip_skb_dst_mtu(skb);
- if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
- (IPCB(skb)->frag_max_size &&
- IPCB(skb)->frag_max_size > mtu))) {
- IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
- icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
- htonl(mtu));
- kfree_skb(skb);
- return -EMSGSIZE;
- }
/*
* Setup starting values.
@@ -751,7 +767,7 @@ fail:
IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
return err;
}
-EXPORT_SYMBOL(ip_fragment);
+EXPORT_SYMBOL(ip_do_fragment);
int
ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)

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