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/*
* IPV4 GSO/GRO offload support
* Linux INET implementation
*
* Copyright (C) 2016 secunet Security Networks AG
* Author: Steffen Klassert <steffen.klassert@secunet.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* ESP GRO support
*/
#include <linux/skbuff.h>
#include <linux/init.h>
#include <net/protocol.h>
#include <crypto/aead.h>
#include <crypto/authenc.h>
#include <linux/err.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/esp.h>
#include <linux/scatterlist.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <net/udp.h>
static struct sk_buff **esp4_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
int offset = skb_gro_offset(skb);
struct xfrm_offload *xo;
struct xfrm_state *x;
__be32 seq;
__be32 spi;
int err;
skb_pull(skb, offset);
if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
goto out;
xo = xfrm_offload(skb);
if (!xo || !(xo->flags & CRYPTO_DONE)) {
err = secpath_set(skb);
if (err)
goto out;
if (skb->sp->len == XFRM_MAX_DEPTH)
goto out;
x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
(xfrm_address_t *)&ip_hdr(skb)->daddr,
spi, IPPROTO_ESP, AF_INET);
if (!x)
goto out;
skb->sp->xvec[skb->sp->len++] = x;
skb->sp->olen++;
xo = xfrm_offload(skb);
if (!xo) {
xfrm_state_put(x);
goto out;
}
}
xo->flags |= XFRM_GRO;
XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
XFRM_SPI_SKB_CB(skb)->family = AF_INET;
XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
XFRM_SPI_SKB_CB(skb)->seq = seq;
/* We don't need to handle errors from xfrm_input, it does all
* the error handling and frees the resources on error. */
xfrm_input(skb, IPPROTO_ESP, spi, -2);
return ERR_PTR(-EINPROGRESS);
out:
skb_push(skb, offset);
NAPI_GRO_CB(skb)->same_flow = 0;
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
{
struct ip_esp_hdr *esph;
struct iphdr *iph = ip_hdr(skb);
struct xfrm_offload *xo = xfrm_offload(skb);
int proto = iph->protocol;
skb_push(skb, -skb_network_offset(skb));
esph = ip_esp_hdr(skb);
*skb_mac_header(skb) = IPPROTO_ESP;
esph->spi = x->id.spi;
esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
xo->proto = proto;
}
static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
__u32 seq;
int err = 0;
struct sk_buff *skb2;
struct xfrm_state *x;
struct ip_esp_hdr *esph;
struct crypto_aead *aead;
struct sk_buff *segs = ERR_PTR(-EINVAL);
netdev_features_t esp_features = features;
struct xfrm_offload *xo = xfrm_offload(skb);
if (!xo)
goto out;
seq = xo->seq.low;
x = skb->sp->xvec[skb->sp->len - 1];
aead = x->data;
esph = ip_esp_hdr(skb);
if (esph->spi != x->id.spi)
goto out;
if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
goto out;
__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
skb->encap_hdr_csum = 1;
if (!(features & NETIF_F_HW_ESP))
esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
segs = x->outer_mode->gso_segment(x, skb, esp_features);
if (IS_ERR_OR_NULL(segs))
goto out;
__skb_pull(skb, skb->data - skb_mac_header(skb));
skb2 = segs;
do {
struct sk_buff *nskb = skb2->next;
xo = xfrm_offload(skb2);
xo->flags |= XFRM_GSO_SEGMENT;
xo->seq.low = seq;
xo->seq.hi = xfrm_replay_seqhi(x, seq);
if(!(features & NETIF_F_HW_ESP))
xo->flags |= CRYPTO_FALLBACK;
x->outer_mode->xmit(x, skb2);
err = x->type_offload->xmit(x, skb2, esp_features);
if (err) {
kfree_skb_list(segs);
return ERR_PTR(err);
}
if (!skb_is_gso(skb2))
seq++;
else
seq += skb_shinfo(skb2)->gso_segs;
skb_push(skb2, skb2->mac_len);
skb2 = nskb;
} while (skb2);
out:
return segs;
}
static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
{
struct crypto_aead *aead = x->data;
struct xfrm_offload *xo = xfrm_offload(skb);
if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
return -EINVAL;
if (!(xo->flags & CRYPTO_DONE))
skb->ip_summed = CHECKSUM_NONE;
return esp_input_done2(skb, 0);
}
static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
{
int err;
int alen;
int blksize;
struct xfrm_offload *xo;
struct ip_esp_hdr *esph;
struct crypto_aead *aead;
struct esp_info esp;
bool hw_offload = true;
esp.inplace = true;
xo = xfrm_offload(skb);
if (!xo)
return -EINVAL;
if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle ||
(x->xso.dev != skb->dev)) {
xo->flags |= CRYPTO_FALLBACK;
hw_offload = false;
}
esp.proto = xo->proto;
/* skb is pure payload to encrypt */
aead = x->data;
alen = crypto_aead_authsize(aead);
esp.tfclen = 0;
/* XXX: Add support for tfc padding here. */
blksize = ALIGN(crypto_aead_blocksize(aead), 4);
esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
esp.plen = esp.clen - skb->len - esp.tfclen;
esp.tailen = esp.tfclen + esp.plen + alen;
esp.esph = ip_esp_hdr(skb);
if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
esp.nfrags = esp_output_head(x, skb, &esp);
if (esp.nfrags < 0)
return esp.nfrags;
}
esph = esp.esph;
esph->spi = x->id.spi;
skb_push(skb, -skb_network_offset(skb));
if (xo->flags & XFRM_GSO_SEGMENT) {
esph->seq_no = htonl(xo->seq.low);
} else {
ip_hdr(skb)->tot_len = htons(skb->len);
ip_send_check(ip_hdr(skb));
}
if (hw_offload)
return 0;
esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
err = esp_output_tail(x, skb, &esp);
if (err)
return err;
secpath_reset(skb);
return 0;
}
static const struct net_offload esp4_offload = {
.callbacks = {
.gro_receive = esp4_gro_receive,
.gso_segment = esp4_gso_segment,
},
};
static const struct xfrm_type_offload esp_type_offload = {
.description = "ESP4 OFFLOAD",
.owner = THIS_MODULE,
.proto = IPPROTO_ESP,
.input_tail = esp_input_tail,
.xmit = esp_xmit,
.encap = esp4_gso_encap,
};
static int __init esp4_offload_init(void)
{
if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
pr_info("%s: can't add xfrm type offload\n", __func__);
return -EAGAIN;
}
return inet_add_offload(&esp4_offload, IPPROTO_ESP);
}
static void __exit esp4_offload_exit(void)
{
if (xfrm_unregister_type_offload(&esp_type_offload, AF_INET) < 0)
pr_info("%s: can't remove xfrm type offload\n", __func__);
inet_del_offload(&esp4_offload, IPPROTO_ESP);
}
module_init(esp4_offload_init);
module_exit(esp4_offload_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP);
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