ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu...

[~andy/linux] / net / ipv4 / route.c

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index f428935c50dba64b7cf7babd955978ed238fd928..25071b48921cebc4788a1f4b0b5fa118832f5910 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -112,9 +112,6 @@
 #define RT_FL_TOS(oldflp4) \
        ((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
 
-/* IPv4 datagram length is stored into 16bit field (tot_len) */
-#define IP_MAX_MTU     0xFFFF
-
 #define RT_GC_TIMEOUT (300*HZ)
 
 static int ip_rt_max_size;
@@ -1776,8 +1773,12 @@ local_input:
                rth->dst.error= -err;
                rth->rt_flags   &= ~RTCF_LOCAL;
        }
-       if (do_cache)
-               rt_cache_route(&FIB_RES_NH(res), rth);
+       if (do_cache) {
+               if (unlikely(!rt_cache_route(&FIB_RES_NH(res), rth))) {
+                       rth->dst.flags |= DST_NOCACHE;
+                       rt_add_uncached_list(rth);
+               }
+       }
        skb_dst_set(skb, &rth->dst);
        err = 0;
        goto out;