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xfrm: Add support for network devices capable of removing the ESP trailer

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In conjunction with crypto offload [1], removing the ESP trailer by
hardware can potentially improve the performance by avoiding (1) a
cache miss incurred by reading the nexthdr field and (2) the necessity
to calculate the csum value of the trailer in order to keep skb->csum
valid.

This patch introduces the changes to the xfrm stack and merely serves
as an infrastructure. Subsequent patch to mlx5 driver will put this to
a good use.

[1] https://www.mail-archive.com/netdev@vger.kernel.org/msg175733.html

Signed-off-by: Yossi Kuperman <yossiku@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Yossi Kuperman 2017-08-30 11:30:39 +03:00 committed by Steffen Klassert
parent acfb98b996
commit 47ebcc0bb1
4 changed files with 89 additions and 38 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
include/net/xfrm.h
View file

@ -1019,6 +1019,7 @@ struct xfrm_offload {
#define CRYPTO_FALLBACK 8
#define XFRM_GSO_SEGMENT 16
#define XFRM_GRO 32
#define XFRM_ESP_NO_TRAILER 64
__u32 status;
#define CRYPTO_SUCCESS 1

70
net/ipv4/esp4.c
View file

@ -499,19 +499,59 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
return esp_output_tail(x, skb, &esp);
}
static inline int esp_remove_trailer(struct sk_buff *skb)
{
struct xfrm_state *x = xfrm_input_state(skb);
struct xfrm_offload *xo = xfrm_offload(skb);
struct crypto_aead *aead = x->data;
int alen, hlen, elen;
int padlen, trimlen;
__wsum csumdiff;
u8 nexthdr[2];
int ret;
alen = crypto_aead_authsize(aead);
hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
elen = skb->len - hlen;
if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
ret = xo->proto;
goto out;
}
if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
BUG();
ret = -EINVAL;
padlen = nexthdr[0];
if (padlen + 2 + alen >= elen) {
net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
padlen + 2, elen - alen);
goto out;
}
trimlen = alen + padlen + 2;
if (skb->ip_summed == CHECKSUM_COMPLETE) {
csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
skb->csum = csum_block_sub(skb->csum, csumdiff,
skb->len - trimlen);
}
pskb_trim(skb, skb->len - trimlen);
ret = nexthdr[1];
out:
return ret;
}
int esp_input_done2(struct sk_buff *skb, int err)
{
const struct iphdr *iph;
struct xfrm_state *x = xfrm_input_state(skb);
struct xfrm_offload *xo = xfrm_offload(skb);
struct crypto_aead *aead = x->data;
int alen = crypto_aead_authsize(aead);
int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
int elen = skb->len - hlen;
int ihl;
u8 nexthdr[2];
int padlen, trimlen;
__wsum csumdiff;
if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
kfree(ESP_SKB_CB(skb)->tmp);
@ -519,16 +559,10 @@ int esp_input_done2(struct sk_buff *skb, int err)
if (unlikely(err))
goto out;
if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
BUG();
err = -EINVAL;
padlen = nexthdr[0];
if (padlen + 2 + alen >= elen)
err = esp_remove_trailer(skb);
if (unlikely(err < 0))
goto out;
/* ... check padding bits here. Silly. :-) */
iph = ip_hdr(skb);
ihl = iph->ihl * 4;
@ -569,22 +603,12 @@ int esp_input_done2(struct sk_buff *skb, int err)
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
trimlen = alen + padlen + 2;
if (skb->ip_summed == CHECKSUM_COMPLETE) {
csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
skb->csum = csum_block_sub(skb->csum, csumdiff,
skb->len - trimlen);
}
pskb_trim(skb, skb->len - trimlen);
skb_pull_rcsum(skb, hlen);
if (x->props.mode == XFRM_MODE_TUNNEL)
skb_reset_transport_header(skb);
else
skb_set_transport_header(skb, -ihl);
err = nexthdr[1];
/* RFC4303: Drop dummy packets without any error */
if (err == IPPROTO_NONE)
err = -EINVAL;

51
net/ipv6/esp6.c
View file

@ -461,29 +461,30 @@ static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
return esp6_output_tail(x, skb, &esp);
}
int esp6_input_done2(struct sk_buff *skb, int err)
static inline int esp_remove_trailer(struct sk_buff *skb)
{
struct xfrm_state *x = xfrm_input_state(skb);
struct xfrm_offload *xo = xfrm_offload(skb);
struct crypto_aead *aead = x->data;
int alen = crypto_aead_authsize(aead);
int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
int elen = skb->len - hlen;
int hdr_len = skb_network_header_len(skb);
int alen, hlen, elen;
int padlen, trimlen;
__wsum csumdiff;
u8 nexthdr[2];
int ret;
if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
kfree(ESP_SKB_CB(skb)->tmp);
alen = crypto_aead_authsize(aead);
hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
elen = skb->len - hlen;
if (unlikely(err))
if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
ret = xo->proto;
goto out;
}
if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
BUG();
err = -EINVAL;
ret = -EINVAL;
padlen = nexthdr[0];
if (padlen + 2 + alen >= elen) {
net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
@ -491,26 +492,46 @@ int esp6_input_done2(struct sk_buff *skb, int err)
goto out;
}
/* ... check padding bits here. Silly. :-) */
trimlen = alen + padlen + 2;
if (skb->ip_summed == CHECKSUM_COMPLETE) {
skb_postpull_rcsum(skb, skb_network_header(skb),
skb_network_header_len(skb));
csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
skb->csum = csum_block_sub(skb->csum, csumdiff,
skb->len - trimlen);
}
pskb_trim(skb, skb->len - trimlen);
ret = nexthdr[1];
out:
return ret;
}
int esp6_input_done2(struct sk_buff *skb, int err)
{
struct xfrm_state *x = xfrm_input_state(skb);
struct xfrm_offload *xo = xfrm_offload(skb);
struct crypto_aead *aead = x->data;
int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
int hdr_len = skb_network_header_len(skb);
if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
kfree(ESP_SKB_CB(skb)->tmp);
if (unlikely(err))
goto out;
err = esp_remove_trailer(skb);
if (unlikely(err < 0))
goto out;
skb_postpull_rcsum(skb, skb_network_header(skb),
skb_network_header_len(skb));
skb_pull_rcsum(skb, hlen);
if (x->props.mode == XFRM_MODE_TUNNEL)
skb_reset_transport_header(skb);
else
skb_set_transport_header(skb, -hdr_len);
err = nexthdr[1];
/* RFC4303: Drop dummy packets without any error */
if (err == IPPROTO_NONE)
err = -EINVAL;

5
net/xfrm/xfrm_input.c
View file

@ -247,6 +247,11 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
goto drop;
}
if (xo->status & CRYPTO_INVALID_PROTOCOL) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
goto drop;
}
XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
goto drop;
}