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authorBenjamin Poirier <bpoirier@suse.de>2012-05-24 11:32:38 +0000
committerDavid S. Miller <davem@davemloft.net>2012-05-27 01:08:29 -0400
commit91657eafb64b4cb53ec3a2fbc4afc3497f735788 (patch)
treef56665f166dc09e0a2969ee17adb745c5fc89459 /net/ipv6
parentf0d1b3c2bcc5de8a17af5f2274f7fcde8292b5fc (diff)
xfrm: take net hdr len into account for esp payload size calculation
Corrects the function that determines the esp payload size. The calculations done in esp{4,6}_get_mtu() lead to overlength frames in transport mode for certain mtu values and suboptimal frames for others. According to what is done, mainly in esp{,6}_output() and tcp_mtu_to_mss(), net_header_len must be taken into account before doing the alignment calculation. Signed-off-by: Benjamin Poirier <bpoirier@suse.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/esp6.c18
1 files changed, 7 insertions, 11 deletions
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 1e62b7557b00..db1521fcda5b 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -413,19 +413,15 @@ static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
struct esp_data *esp = x->data;
u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
u32 align = max_t(u32, blksize, esp->padlen);
- u32 rem;
+ unsigned int net_adj;
- mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
- rem = mtu & (align - 1);
- mtu &= ~(align - 1);
-
- if (x->props.mode != XFRM_MODE_TUNNEL) {
- u32 padsize = ((blksize - 1) & 7) + 1;
- mtu -= blksize - padsize;
- mtu += min_t(u32, blksize - padsize, rem);
- }
+ if (x->props.mode != XFRM_MODE_TUNNEL)
+ net_adj = sizeof(struct ipv6hdr);
+ else
+ net_adj = 0;
- return mtu - 2;
+ return ((mtu - x->props.header_len - crypto_aead_authsize(esp->aead) -
+ net_adj) & ~(align - 1)) + (net_adj - 2);
}
static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,