diff options
| author | Patrick McHardy <kaber@trash.net> | 2007-04-09 11:47:18 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-04-25 22:28:38 -0700 |
| commit | c5c2523893747f88a83376abad310c8ad13f7197 (patch) | |
| tree | 58f1ab25ac9f7ca7460abbd24e9bab9c8683f6fd /net/xfrm | |
| parent | 557922584d9c5b6b990bcfb2fec3134f0e73a05d (diff) | |
[XFRM]: Optimize MTU calculation
Replace the probing based MTU estimation, which usually takes 2-3 iterations
to find a fitting value and may underestimate the MTU, by an exact calculation.
Also fix underestimation of the XFRM trailer_len, which causes unnecessary
reallocations.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/xfrm')
| -rw-r--r-- | net/xfrm/xfrm_state.c | 36 |
1 files changed, 8 insertions, 28 deletions
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 63a20e81816..69a3600afd9 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -1667,37 +1667,17 @@ void xfrm_state_delete_tunnel(struct xfrm_state *x) } EXPORT_SYMBOL(xfrm_state_delete_tunnel); -/* - * This function is NOT optimal. For example, with ESP it will give an - * MTU that's usually two bytes short of being optimal. However, it will - * usually give an answer that's a multiple of 4 provided the input is - * also a multiple of 4. - */ int xfrm_state_mtu(struct xfrm_state *x, int mtu) { - int res = mtu; - - res -= x->props.header_len; - - for (;;) { - int m = res; - - if (m < 68) - return 68; - - spin_lock_bh(&x->lock); - if (x->km.state == XFRM_STATE_VALID && - x->type && x->type->get_max_size) - m = x->type->get_max_size(x, m); - else - m += x->props.header_len; - spin_unlock_bh(&x->lock); - - if (m <= mtu) - break; - res -= (m - mtu); - } + int res; + spin_lock_bh(&x->lock); + if (x->km.state == XFRM_STATE_VALID && + x->type && x->type->get_mtu) + res = x->type->get_mtu(x, mtu); + else + res = mtu; + spin_unlock_bh(&x->lock); return res; } |