From 47ebcc0bb1d5eb7f1b1eeab675409ea7f67b4a5c Mon Sep 17 00:00:00 2001 From: Yossi Kuperman Date: Wed, 30 Aug 2017 11:30:39 +0300 Subject: 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 Signed-off-by: Steffen Klassert --- net/ipv6/esp6.c | 51 ++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 36 insertions(+), 15 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index 74bde202eb9a..7fb41b0ad437 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -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; -- cgit v1.2.3