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// SPDX-License-Identifier: GPL-2.0-only
/*
* Network Service Header
*
* Copyright (c) 2017 Red Hat, Inc. -- Jiri Benc <jbenc@redhat.com>
*/
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/gso.h>
#include <net/nsh.h>
#include <net/tun_proto.h>
int nsh_push(struct sk_buff *skb, const struct nshhdr *pushed_nh)
{
struct nshhdr *nh;
size_t length = nsh_hdr_len(pushed_nh);
u8 next_proto;
if (skb->mac_len) {
next_proto = TUN_P_ETHERNET;
} else {
next_proto = tun_p_from_eth_p(skb->protocol);
if (!next_proto)
return -EAFNOSUPPORT;
}
/* Add the NSH header */
if (skb_cow_head(skb, length) < 0)
return -ENOMEM;
skb_push(skb, length);
nh = (struct nshhdr *)(skb->data);
memcpy(nh, pushed_nh, length);
nh->np = next_proto;
skb_postpush_rcsum(skb, nh, length);
skb->protocol = htons(ETH_P_NSH);
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_reset_mac_len(skb);
return 0;
}
EXPORT_SYMBOL_GPL(nsh_push);
int nsh_pop(struct sk_buff *skb)
{
struct nshhdr *nh;
size_t length;
__be16 inner_proto;
if (!pskb_may_pull(skb, NSH_BASE_HDR_LEN))
return -ENOMEM;
nh = (struct nshhdr *)(skb->data);
length = nsh_hdr_len(nh);
if (length < NSH_BASE_HDR_LEN)
return -EINVAL;
inner_proto = tun_p_to_eth_p(nh->np);
if (!pskb_may_pull(skb, length))
return -ENOMEM;
if (!inner_proto)
return -EAFNOSUPPORT;
skb_pull_rcsum(skb, length);
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
skb_reset_mac_len(skb);
skb->protocol = inner_proto;
return 0;
}
EXPORT_SYMBOL_GPL(nsh_pop);
static struct sk_buff *nsh_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
u16 mac_offset = skb->mac_header;
unsigned int nsh_len, mac_len;
__be16 proto;
skb_reset_network_header(skb);
mac_len = skb->mac_len;
if (unlikely(!pskb_may_pull(skb, NSH_BASE_HDR_LEN)))
goto out;
nsh_len = nsh_hdr_len(nsh_hdr(skb));
if (nsh_len < NSH_BASE_HDR_LEN)
goto out;
if (unlikely(!pskb_may_pull(skb, nsh_len)))
goto out;
proto = tun_p_to_eth_p(nsh_hdr(skb)->np);
if (!proto)
goto out;
__skb_pull(skb, nsh_len);
skb_reset_mac_header(skb);
skb->mac_len = proto == htons(ETH_P_TEB) ? ETH_HLEN : 0;
skb->protocol = proto;
features &= NETIF_F_SG;
segs = skb_mac_gso_segment(skb, features);
if (IS_ERR_OR_NULL(segs)) {
skb_gso_error_unwind(skb, htons(ETH_P_NSH), nsh_len,
mac_offset, mac_len);
goto out;
}
for (skb = segs; skb; skb = skb->next) {
skb->protocol = htons(ETH_P_NSH);
__skb_push(skb, nsh_len);
skb->mac_header = mac_offset;
skb->network_header = skb->mac_header + mac_len;
skb->mac_len = mac_len;
}
out:
return segs;
}
static struct packet_offload nsh_packet_offload __read_mostly = {
.type = htons(ETH_P_NSH),
.priority = 15,
.callbacks = {
.gso_segment = nsh_gso_segment,
},
};
static int __init nsh_init_module(void)
{
dev_add_offload(&nsh_packet_offload);
return 0;
}
static void __exit nsh_cleanup_module(void)
{
dev_remove_offload(&nsh_packet_offload);
}
module_init(nsh_init_module);
module_exit(nsh_cleanup_module);
MODULE_AUTHOR("Jiri Benc <jbenc@redhat.com>");
MODULE_DESCRIPTION("NSH protocol");
MODULE_LICENSE("GPL v2");
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