diff options
| author | Benjamin Poirier | 2012-05-24 11:32:38 +0000 |
|---|---|---|
| committer | David S. Miller | 2012-05-27 01:08:29 -0400 |
| commit | 91657eafb64b4cb53ec3a2fbc4afc3497f735788 (patch) | |
| tree | f56665f166dc09e0a2969ee17adb745c5fc89459 /net/ipv4/esp4.c | |
| parent | f0d1b3c2bcc5de8a17af5f2274f7fcde8292b5fc (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/ipv4/esp4.c')
| -rw-r--r-- | net/ipv4/esp4.c | 24 |
1 files changed, 9 insertions, 15 deletions
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index 89a47b35905d..cb982a61536f 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -459,28 +459,22 @@ 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) |