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authorYossi Kuperman <yossiku@mellanox.com>2017-08-30 11:30:39 +0300
committerSteffen Klassert <steffen.klassert@secunet.com>2017-08-31 10:04:03 +0300
commit47ebcc0bb1d5eb7f1b1eeab675409ea7f67b4a5c (patch)
tree1718a09f7321053903a758a82b0101595113cad0 /net/ipv4/esp4.c
parentacfb98b99647aa7dc7c111db52d5f4199d2b641f (diff)
downloadlinux-47ebcc0bb1d5eb7f1b1eeab675409ea7f67b4a5c.tar.xz
xfrm: Add support for network devices capable of removing the ESP trailer
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>
Diffstat (limited to 'net/ipv4/esp4.c')
-rw-r--r--net/ipv4/esp4.c70
1 files changed, 47 insertions, 23 deletions
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 741acd7b9646..319000573bc7 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -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;