# \[PATCH\] ipv4: Cap ADVMSS metric in the FIB rather than the routing cache. - From: David Miller \ - Date: 2012-06-18 02:53:58 - List: netdev - Page: https://ratatoskr.run/netdev/2012/06/10897350 ```text It makes no sense to execute this limit test every time we create a routing cache entry. We can't simply error out on these things since we've silently accepted and truncated them forever. Signed-off-by: David S. Miller --- net/ipv4/fib_semantics.c | 7 ++++++- net/ipv4/route.c | 2 -- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index e5b7182..415f823 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -779,9 +779,14 @@ struct fib_info *fib_create_info(struct fib_config *cfg) int type = nla_type(nla); if (type) { + u32 val; + if (type > RTAX_MAX) goto err_inval; - fi->fib_metrics[type - 1] = nla_get_u32(nla); + val = nla_get_u32(nla); + if (type == RTAX_ADVMSS && val > 65535 - 40) + val = 65535 - 40; + fi->fib_metrics[type - 1] = val; } } } diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 41df529..a91f6d3 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1951,8 +1951,6 @@ static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4, if (dst_mtu(dst) > IP_MAX_MTU) dst_metric_set(dst, RTAX_MTU, IP_MAX_MTU); - if (dst_metric_raw(dst, RTAX_ADVMSS) > 65535 - 40) - dst_metric_set(dst, RTAX_ADVMSS, 65535 - 40); #ifdef CONFIG_IP_ROUTE_CLASSID #ifdef CONFIG_IP_MULTIPLE_TABLES -- 1.7.10 ```