xfrm4: Invalidate all ipv4 routes on IPsec pmtu events

On IPsec pmtu events we can't access the transport headers of
the original packet, so we can't find the socket that sent
the packet. The only chance to notify the socket about the
pmtu change is to force a relookup for all routes. This
patch implenents this for the IPsec protocols.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

3 files changed, 15 insertions, 6 deletions

diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index a154d0a08c79..a69b4e4a02b5 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -420,9 +420,12 @@ static void ah4_err(struct sk_buff *skb, u32 info)
         if (!x)
                 return;
 
-        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
+        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) {
+                atomic_inc(&flow_cache_genid);
+                rt_genid_bump(net);
+
                 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_AH, 0);
-        else
+        } else
                 ipv4_redirect(skb, net, 0, 0, IPPROTO_AH, 0);
         xfrm_state_put(x);
 }
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index fd26ff4f3eac..3b4f0cd2e63e 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -502,9 +502,12 @@ static void esp4_err(struct sk_buff *skb, u32 info)
         if (!x)
                 return;
 
-        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
+        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) {
+                atomic_inc(&flow_cache_genid);
+                rt_genid_bump(net);
+
                 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
-        else
+        } else
                 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
         xfrm_state_put(x);
 }
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index d3ab47e19a89..9a46daed2f3c 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -47,9 +47,12 @@ static void ipcomp4_err(struct sk_buff *skb, u32 info)
         if (!x)
                 return;
 
-        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
+        if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) {
+                atomic_inc(&flow_cache_genid);
+                rt_genid_bump(net);
+
                 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_COMP, 0);
-        else
+        } else
                 ipv4_redirect(skb, net, 0, 0, IPPROTO_COMP, 0);
         xfrm_state_put(x);
 }