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Commit 91657eaf authored by Benjamin Poirier's avatar Benjamin Poirier Committed by David S. Miller
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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: default avatarBenjamin Poirier <bpoirier@suse.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f0d1b3c2

net/ipv4/esp4.c

+9 −15
Original line number Diff line number Diff line
@@ -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)

net/ipv6/esp6.c

+7 −11
Original line number Diff line number Diff line
@@ -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,