/*
* IPV6 GSO/GRO offload support
* Linux INET6 implementation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/socket.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/printk.h>
#include <net/protocol.h>
#include <net/ipv6.h>
#include "ip6_offload.h"
static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
{
const struct net_offload *ops = NULL;
for (;;) {
struct ipv6_opt_hdr *opth;
int len;
if (proto != NEXTHDR_HOP) {
ops = rcu_dereference(inet6_offloads[proto]);
if (unlikely(!ops))
break;
if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
break;
}
if (unlikely(!pskb_may_pull(skb, 8)))
break;
opth = (void *)skb->data;
len = ipv6_optlen(opth);
if (unlikely(!pskb_may_pull(skb, len)))
break;
proto = opth->nexthdr;
__skb_pull(skb, len);
}
return proto;
}
static int ipv6_gso_send_check(struct sk_buff *skb)
{
const struct ipv6hdr *ipv6h;
const struct net_offload *ops;
int err = -EINVAL;
if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
goto out;
ipv6h = ipv6_hdr(skb);
__skb_pull(skb, sizeof(*ipv6h));
err = -EPROTONOSUPPORT;
rcu_read_lock();
ops = rcu_dereference(inet6_offloads[
ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr)]);
if (likely(ops && ops->callbacks.gso_send_check)) {
skb_reset_transport_header(skb);
err = ops->callbacks.gso_send_check(skb);
}
rcu_read_unlock();
out:
return err;
}
static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
struct sk_buff *segs = ERR_PTR(-EINVAL);
struct ipv6hdr *ipv6h;
const struct net_offload *ops;
int proto;
struct frag_hdr *fptr;
unsigned int unfrag_ip6hlen;
u8 *prevhdr;
int offset = 0;
if (unlikely(skb_shinfo(skb)->gso_type &
~(SKB_GSO_UDP |
SKB_GSO_DODGY |
SKB_GSO_TCP_ECN |
SKB_GSO_GRE |
SKB_GSO_UDP_TUNNEL |
SKB_GSO_MPLS |
SKB_GSO_TCPV6 |
0)))
goto out;
if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
goto out;
ipv6h = ipv6_hdr(skb);
__skb_pull(skb, sizeof(*ipv6h));
segs = ERR_PTR(-EPROTONOSUPPORT);
proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
rcu_read_lock();
ops = rcu_dereference(inet6_offloads[proto]);
if (likely(ops && ops->callbacks.gso_segment)) {
skb_reset_transport_header(skb);
segs = ops->callbacks.gso_segment(skb, features);
}
rcu_read_unlock();
if (IS_ERR(segs))
goto out;
for (skb = segs; skb; skb = skb->next) {
ipv6h = ipv6_hdr(skb);
ipv6h->payload_len = htons(skb->len - skb->mac_len -
sizeof(*ipv6h));
if (proto == IPPROTO_UDP) {
unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
fptr = (struct frag_hdr *)(skb_network_header(skb) +
unfrag_ip6hlen);
fptr->frag_off = htons(offset);
if (skb->next != NULL)
fptr->frag_off |= htons(IP6_MF);
offset += (ntohs(ipv6h->payload_len) -
sizeof(struct frag_hdr));
}
}
out:
return segs;
}
static struct sk_buff **ipv6_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
const struct net_offload *ops;
struct sk_buff **pp = NULL;
struct sk_buff *p;
struct ipv6hdr *iph;
unsigned int nlen;
unsigned int hlen;
unsigned int off;
int flush = 1;
int proto;
__wsum csum;
off = skb_gro_offset(skb);
hlen = off + sizeof(*iph);
iph = skb_gro_header_fast(skb, off);
if (skb_gro_header_hard(skb, hlen)) {
iph = skb_gro_header_slow(skb, hlen, off);
if (unlikely(!iph))
goto out;
}
skb_gro_pull(skb, sizeof(*iph));
skb_set_transport_header(skb, skb_gro_offset(skb));
flush += ntohs(iph->payload_len) != skb_gro_len(skb);
rcu_read_lock();
proto = iph->nexthdr;
ops = rcu_dereference(inet6_offloads[proto]);
if (!ops || !ops->callbacks.gro_receive) {
__pskb_pull(skb, skb_gro_offset(skb));
proto = ipv6_gso_pull_exthdrs(skb, proto);
skb_gro_pull(skb, -skb_transport_offset(skb));
skb_reset_transport_header(skb);
__skb_push(skb, skb_gro_offset(skb));
ops = rcu_dereference(inet6_offloads[proto]);
if (!ops || !ops->callbacks.gro_receive)
goto out_unlock;
iph = ipv6_hdr(skb);
}
NAPI_GRO_CB(skb)->proto = proto;
flush--;
nlen = skb_network_header_len(skb);
for (p = *head; p; p = p->next) {
const struct ipv6hdr *iph2;
__be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
if (!NAPI_GRO_CB(p)->same_flow)
continue;
iph2 = ipv6_hdr(p);
first_word = *(__be32 *)iph ^ *(__be32 *)iph2 ;
/* All fields must match except length and Traffic Class. */
if (nlen != skb_network_header_len(p) ||
(first_word & htonl(0xF00FFFFF)) ||
memcmp(&iph->nexthdr, &iph2->nexthdr,
nlen - offsetof(struct ipv6hdr, nexthdr))) {
NAPI_GRO_CB(p)->same_flow = 0;
continue;
}
/* flush if Traffic Class fields are different */
NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
NAPI_GRO_CB(p)->flush |= flush;
}
NAPI_GRO_CB(skb)->flush |= flush;
csum = skb->csum;
skb_postpull_rcsum(skb, iph, skb_network_header_len(skb));
pp = ops->callbacks.gro_receive(head, skb);
skb->csum = csum;
out_unlock:
rcu_read_unlock();
out:
NAPI_GRO_CB(skb)->flush |= flush;
return pp;
}
static int ipv6_gro_complete(struct sk_buff *skb)
{
const struct net_offload *ops;
struct ipv6hdr *iph = ipv6_hdr(skb);
int err = -ENOSYS;
iph->payload_len = htons(skb->len - skb_network_offset(skb) -
sizeof(*iph));
rcu_read_lock();
ops = rcu_dereference(inet6_offloads[NAPI_GRO_CB(skb)->proto]);
if (WARN_ON(!ops || !ops->callbacks.gro_complete))
goto out_unlock;
err = ops->callbacks.gro_complete(skb);
out_unlock:
rcu_read_unlock();
return err;
}
static struct packet_offload ipv6_packet_offload __read_mostly = {
.type = cpu_to_be16(ETH_P_IPV6),
.callbacks = {
.gso_send_check = ipv6_gso_send_check,
.gso_segment = ipv6_gso_segment,
.gro_receive = ipv6_gro_receive,
.gro_complete = ipv6_gro_complete,
},
};
static int __init ipv6_offload_init(void)
{
if (tcpv6_offload_init() < 0)
pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
if (udp_offload_init() < 0)
pr_crit("%s: Cannot add UDP protocol offload\n", __func__);
if (ipv6_exthdrs_offload_init() < 0)
pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
dev_add_offload(&ipv6_packet_offload);
return 0;
}
fs_initcall(ipv6_offload_init);
