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/*
* IPV6 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/ip6_route.h>
#include <net/ipv6.h>
#include <linux/icmpv6.h>
static __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen)
{
int off = sizeof(struct ipv6hdr);
struct ipv6_opt_hdr *exthdr;
if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP))
return offsetof(struct ipv6hdr, nexthdr);
while (off < nhlen) {
exthdr = (void *)ipv6_hdr + off;
if (exthdr->nexthdr == NEXTHDR_ESP)
return off;
off += ipv6_optlen(exthdr);
}
return 0;
}
static struct sk_buff *esp6_gro_receive(struct list_head *head,
struct sk_buff *skb)
{
int offset = skb_gro_offset(skb);
struct xfrm_offload *xo;
struct xfrm_state *x;
__be32 seq;
__be32 spi;
int nhoff;
int err;
if (!pskb_pull(skb, offset))
return NULL;
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 *)&ipv6_hdr(skb)->daddr,
spi, IPPROTO_ESP, AF_INET6);
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;
nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
if (!nhoff)
goto out;
IP6CB(skb)->nhoff = nhoff;
XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, 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 esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
{
struct ip_esp_hdr *esph;
struct ipv6hdr *iph = ipv6_hdr(skb);
struct xfrm_offload *xo = xfrm_offload(skb);
u8 proto = iph->nexthdr;
skb_push(skb, -skb_network_offset(skb));
if (x->outer_mode->encap == XFRM_MODE_TRANSPORT) {
__be16 frag;
ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &proto, &frag);
}
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 *esp6_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct xfrm_state *x;
struct ip_esp_hdr *esph;
struct crypto_aead *aead;
netdev_features_t esp_features = features;
struct xfrm_offload *xo = xfrm_offload(skb);
if (!xo)
return ERR_PTR(-EINVAL);
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
return ERR_PTR(-EINVAL);
x = skb->sp->xvec[skb->sp->len - 1];
aead = x->data;
esph = ip_esp_hdr(skb);
if (esph->spi != x->id.spi)
return ERR_PTR(-EINVAL);
if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
return ERR_PTR(-EINVAL);
__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
skb->encap_hdr_csum = 1;
if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
esp_features = features & ~NETIF_F_CSUM_MASK;
xo->flags |= XFRM_GSO_SEGMENT;
return x->outer_mode->gso_segment(x, skb, esp_features);
}
static int esp6_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 esp6_input_done2(skb, 0);
}
static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
{
int len;
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;
__u32 seq;
esp.inplace = true;
xo = xfrm_offload(skb);
if (!xo)
return -EINVAL;
if (!(features & NETIF_F_HW_ESP) || 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;
if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
esp.nfrags = esp6_output_head(x, skb, &esp);
if (esp.nfrags < 0)
return esp.nfrags;
}
seq = xo->seq.low;
esph = ip_esp_hdr(skb);
esph->spi = x->id.spi;
skb_push(skb, -skb_network_offset(skb));
if (xo->flags & XFRM_GSO_SEGMENT) {
esph->seq_no = htonl(seq);
if (!skb_is_gso(skb))
xo->seq.low++;
else
xo->seq.low += skb_shinfo(skb)->gso_segs;
}
esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
len = skb->len - sizeof(struct ipv6hdr);
if (len > IPV6_MAXPLEN)
len = 0;
ipv6_hdr(skb)->payload_len = htons(len);
if (hw_offload)
return 0;
err = esp6_output_tail(x, skb, &esp);
if (err)
return err;
secpath_reset(skb);
if (skb_needs_linearize(skb, skb->dev->features) &&
__skb_linearize(skb))
return -ENOMEM;
return 0;
}
static const struct net_offload esp6_offload = {
.callbacks = {
.gro_receive = esp6_gro_receive,
.gso_segment = esp6_gso_segment,
},
};
static const struct xfrm_type_offload esp6_type_offload = {
.description = "ESP6 OFFLOAD",
.owner = THIS_MODULE,
.proto = IPPROTO_ESP,
.input_tail = esp6_input_tail,
.xmit = esp6_xmit,
.encap = esp6_gso_encap,
};
static int __init esp6_offload_init(void)
{
if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
pr_info("%s: can't add xfrm type offload\n", __func__);
return -EAGAIN;
}
return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
}
static void __exit esp6_offload_exit(void)
{
if (xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6) < 0)
pr_info("%s: can't remove xfrm type offload\n", __func__);
inet6_del_offload(&esp6_offload, IPPROTO_ESP);
}
module_init(esp6_offload_init);
module_exit(esp6_offload_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
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