diff options
Diffstat (limited to 'net/ipv4/ip_fragment.c')
| -rw-r--r-- | net/ipv4/ip_fragment.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index eb9d63a570cd..f55a4e61bfb8 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -851,14 +851,22 @@ static inline void ip4_frags_ctl_register(void) static int __net_init ipv4_frags_init_net(struct net *net) { - /* - * Fragment cache limits. We will commit 256K at one time. Should we - * cross that limit we will prune down to 192K. This should cope with - * even the most extreme cases without allowing an attacker to - * measurably harm machine performance. + /* Fragment cache limits. + * + * The fragment memory accounting code, (tries to) account for + * the real memory usage, by measuring both the size of frag + * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) + * and the SKB's truesize. + * + * A 64K fragment consumes 129736 bytes (44*2944)+200 + * (1500 truesize == 2944, sizeof(struct ipq) == 200) + * + * We will commit 4MB at one time. Should we cross that limit + * we will prune down to 3MB, making room for approx 8 big 64K + * fragments 8x128k. */ - net->ipv4.frags.high_thresh = 256 * 1024; - net->ipv4.frags.low_thresh = 192 * 1024; + net->ipv4.frags.high_thresh = 4 * 1024 * 1024; + net->ipv4.frags.low_thresh = 3 * 1024 * 1024; /* * Important NOTE! Fragment queue must be destroyed before MSL expires. * RFC791 is wrong proposing to prolongate timer each fragment arrival |