linux/net/ipv4/esp4_offload.c
Steffen Klassert 23c7f8d798 net: Fix esp GSO on inter address family tunnels.
The esp tunnel GSO handlers use skb_mac_gso_segment to
push the inner packet to the segmentation handlers.
However, skb_mac_gso_segment takes the Ethernet Protocol
ID from 'skb->protocol' which is wrong for inter address
family tunnels. We fix this by introducing a new
skb_eth_gso_segment function.

This function can be used if it is necessary to pass the
Ethernet Protocol ID directly to the segmentation handler.
First users of this function will be the esp4 and esp6
tunnel segmentation handlers.

Fixes: c35fe4106b ("xfrm: Add mode handlers for IPsec on layer 2")
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2022-03-07 13:14:04 +01:00

377 lines
8.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* IPV4 GSO/GRO offload support
* Linux INET implementation
*
* Copyright (C) 2016 secunet Security Networks AG
* Author: Steffen Klassert <steffen.klassert@secunet.com>
*
* 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/gro.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 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;
if (!pskb_pull(skb, offset))
return NULL;
if (xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq) != 0)
goto out;
xo = xfrm_offload(skb);
if (!xo || !(xo->flags & CRYPTO_DONE)) {
struct sec_path *sp = secpath_set(skb);
if (!sp)
goto out;
if (sp->len == XFRM_MAX_DEPTH)
goto out_reset;
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_reset;
skb->mark = xfrm_smark_get(skb->mark, x);
sp->xvec[sp->len++] = x;
sp->olen++;
xo = xfrm_offload(skb);
if (!xo)
goto out_reset;
}
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_reset:
secpath_reset(skb);
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 *xfrm4_tunnel_gso_segment(struct xfrm_state *x,
struct sk_buff *skb,
netdev_features_t features)
{
return skb_eth_gso_segment(skb, features, htons(ETH_P_IP));
}
static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
struct sk_buff *skb,
netdev_features_t features)
{
const struct net_offload *ops;
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct xfrm_offload *xo = xfrm_offload(skb);
skb->transport_header += x->props.header_len;
ops = rcu_dereference(inet_offloads[xo->proto]);
if (likely(ops && ops->callbacks.gso_segment))
segs = ops->callbacks.gso_segment(skb, features);
return segs;
}
static struct sk_buff *xfrm4_beet_gso_segment(struct xfrm_state *x,
struct sk_buff *skb,
netdev_features_t features)
{
struct xfrm_offload *xo = xfrm_offload(skb);
struct sk_buff *segs = ERR_PTR(-EINVAL);
const struct net_offload *ops;
u8 proto = xo->proto;
skb->transport_header += x->props.header_len;
if (x->sel.family != AF_INET6) {
if (proto == IPPROTO_BEETPH) {
struct ip_beet_phdr *ph =
(struct ip_beet_phdr *)skb->data;
skb->transport_header += ph->hdrlen * 8;
proto = ph->nexthdr;
} else {
skb->transport_header -= IPV4_BEET_PHMAXLEN;
}
} else {
__be16 frag;
skb->transport_header +=
ipv6_skip_exthdr(skb, 0, &proto, &frag);
if (proto == IPPROTO_TCP)
skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
}
if (proto == IPPROTO_IPV6)
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
__skb_pull(skb, skb_transport_offset(skb));
ops = rcu_dereference(inet_offloads[proto]);
if (likely(ops && ops->callbacks.gso_segment))
segs = ops->callbacks.gso_segment(skb, features);
return segs;
}
static struct sk_buff *xfrm4_outer_mode_gso_segment(struct xfrm_state *x,
struct sk_buff *skb,
netdev_features_t features)
{
switch (x->outer_mode.encap) {
case XFRM_MODE_TUNNEL:
return xfrm4_tunnel_gso_segment(x, skb, features);
case XFRM_MODE_TRANSPORT:
return xfrm4_transport_gso_segment(x, skb, features);
case XFRM_MODE_BEET:
return xfrm4_beet_gso_segment(x, skb, features);
}
return ERR_PTR(-EOPNOTSUPP);
}
static struct sk_buff *esp4_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);
struct sec_path *sp;
if (!xo)
return ERR_PTR(-EINVAL);
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
return ERR_PTR(-EINVAL);
sp = skb_sec_path(skb);
x = sp->xvec[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 ((!(skb->dev->gso_partial_features & NETIF_F_HW_ESP) &&
!(features & NETIF_F_HW_ESP)) || x->xso.dev != skb->dev)
esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
NETIF_F_SCTP_CRC);
else if (!(features & NETIF_F_HW_ESP_TX_CSUM) &&
!(skb->dev->gso_partial_features & NETIF_F_HW_ESP_TX_CSUM))
esp_features = features & ~(NETIF_F_CSUM_MASK |
NETIF_F_SCTP_CRC);
xo->flags |= XFRM_GSO_SEGMENT;
return xfrm4_outer_mode_gso_segment(x, skb, esp_features);
}
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;
__u32 seq;
esp.inplace = true;
xo = xfrm_offload(skb);
if (!xo)
return -EINVAL;
if ((!(features & NETIF_F_HW_ESP) &&
!(skb->dev->gso_partial_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;
esp.esph = ip_esp_hdr(skb);
if (!hw_offload || !skb_is_gso(skb)) {
esp.nfrags = esp_output_head(x, skb, &esp);
if (esp.nfrags < 0)
return esp.nfrags;
}
seq = xo->seq.low;
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(seq);
if (!skb_is_gso(skb))
xo->seq.low++;
else
xo->seq.low += skb_shinfo(skb)->gso_segs;
}
esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32));
ip_hdr(skb)->tot_len = htons(skb->len);
ip_send_check(ip_hdr(skb));
if (hw_offload) {
if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
return -ENOMEM;
xo = xfrm_offload(skb);
if (!xo)
return -EINVAL;
xo->flags |= XFRM_XMIT;
return 0;
}
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 = {
.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)
{
xfrm_unregister_type_offload(&esp_type_offload, AF_INET);
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);
MODULE_DESCRIPTION("IPV4 GSO/GRO offload support");