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authorBenjamin Poirier <bpoirier@suse.de>2012-05-24 11:32:38 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-06-10 00:33:03 +0900
commit570986003b9cd61b7ccf03beacb56f5f5f6f3409 (patch)
treee324b423b52a3c7819b23c603b7064ca7f505eff /net/ipv4
parent09c073a87938a5031b396ad63c8acdfae86fc153 (diff)
xfrm: take net hdr len into account for esp payload size calculation
[ Upstream commit 91657eafb64b4cb53ec3a2fbc4afc3497f735788 ] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/esp4.c24
1 files changed, 9 insertions, 15 deletions
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index a5b413416da3..530787bc1990 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -457,28 +457,22 @@ static u32 esp4_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;
-
- mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
- rem = mtu & (align - 1);
- mtu &= ~(align - 1);
+ unsigned int net_adj;
switch (x->props.mode) {
- case XFRM_MODE_TUNNEL:
- break;
- default:
case XFRM_MODE_TRANSPORT:
- /* The worst case */
- mtu -= blksize - 4;
- mtu += min_t(u32, blksize - 4, rem);
- break;
case XFRM_MODE_BEET:
- /* The worst case. */
- mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
+ net_adj = sizeof(struct iphdr);
break;
+ case XFRM_MODE_TUNNEL:
+ net_adj = 0;
+ break;
+ default:
+ BUG();
}
- return mtu - 2;
+ return ((mtu - x->props.header_len - crypto_aead_authsize(esp->aead) -
+ net_adj) & ~(align - 1)) + (net_adj - 2);
}
static void esp4_err(struct sk_buff *skb, u32 info)