// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IPV6 GSO/GRO offload support
* Linux INET6 implementation
*/
#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 <net/inet_common.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/gro.h>
#include <net/gso.h>
#include "ip6_offload.h"
/* All GRO functions are always builtin, except UDP over ipv6, which lays in
* ipv6 module, as it depends on UDPv6 lookup function, so we need special care
* when ipv6 is built as a module
*/
#if IS_BUILTIN(CONFIG_IPV6)
#define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
#else
#define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
#endif
#define indirect_call_gro_receive_l4(f2, f1, cb, head, skb) \
({ \
unlikely(gro_recursion_inc_test(skb)) ? \
NAPI_GRO_CB(skb)->flush |= 1, NULL : \
INDIRECT_CALL_L4(cb, f2, f1, head, skb); \
})
static int ipv6_gro_pull_exthdrs(struct sk_buff *skb, int off, int proto)
{
const struct net_offload *ops = NULL;
struct ipv6_opt_hdr *opth;
for (;;) {
int len;
ops = rcu_dereference(inet6_offloads[proto]);
if (unlikely(!ops))
break;
if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
break;
opth = skb_gro_header(skb, off + sizeof(*opth), off);
if (unlikely(!opth))
break;
len = ipv6_optlen(opth);
opth = skb_gro_header(skb, off + len, off);
if (unlikely(!opth))
break;
proto = opth->nexthdr;
off += len;
}
skb_gro_pull(skb, off - skb_gro_receive_network_offset(skb));
return proto;
}
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;
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;
opth = (void *)skb->data;
proto = opth->nexthdr;
__skb_pull(skb, len);
}
return proto;
}
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, err;
struct frag_hdr *fptr;
unsigned int payload_len;
u8 *prevhdr;
int offset = 0;
bool encap, udpfrag;
int nhoff;
bool gso_partial;
skb_reset_network_header(skb);
err = ipv6_hopopt_jumbo_remove(skb);
if (err)
return ERR_PTR(err);
nhoff = skb_network_header(skb) - skb_mac_header(skb);
if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
goto out;
encap = SKB_GSO_CB(skb)->encap_level > 0;
if (encap)
features &= skb->dev->hw_enc_features;
SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
ipv6h = ipv6_hdr(skb);
__skb_pull(skb, sizeof(*ipv6h));
segs = ERR_PTR(-EPROTONOSUPPORT);
proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
if (skb->encapsulation &&
skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
udpfrag = proto == IPPROTO_UDP && encap &&
(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
else
udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
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);
if (!segs)
skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
}
if (IS_ERR_OR_NULL(segs))
goto out;
gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
for (skb = segs; skb; skb = skb->next) {
ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
if (gso_partial && skb_is_gso(skb))
payload_len = skb_shinfo(skb)->gso_size +
SKB_GSO_CB(skb)->data_offset +
skb->head - (unsigned char *)(ipv6h + 1);
else
payload_len = skb->len - nhoff - sizeof(*ipv6h);
ipv6h->payload_len = htons(payload_len);
skb->network_header = (u8 *)ipv6h - skb->head;
skb_reset_mac_len(skb);
if (udpfrag) {
int err = ip6_find_1stfragopt(skb, &prevhdr);
if (err < 0) {
kfree_skb_list(segs);
return ERR_PTR(err);
}
fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
fptr->frag_off = htons(offset);
if (skb->next)
fptr->frag_off |= htons(IP6_MF);
offset += (ntohs(ipv6h->payload_len) -
sizeof(struct frag_hdr));
}
if (encap)
skb_reset_inner_headers(skb);
}
out:
return segs;
}
/* Return the total length of all the extension hdrs, following the same
* logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
*/
static int ipv6_exthdrs_len(struct ipv6hdr *iph,
const struct net_offload **opps)
{
struct ipv6_opt_hdr *opth = (void *)iph;
int len = 0, proto, optlen = sizeof(*iph);
proto = iph->nexthdr;
for (;;) {
*opps = rcu_dereference(inet6_offloads[proto]);
if (unlikely(!(*opps)))
break;
if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
break;
opth = (void *)opth + optlen;
optlen = ipv6_optlen(opth);
len += optlen;
proto = opth->nexthdr;
}
return len;
}
INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *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;
u16 flush = 1;
int proto;
off = skb_gro_offset(skb);
hlen = off + sizeof(*iph);
iph = skb_gro_header(skb, hlen, off);
if (unlikely(!iph))
goto out;
NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark] = off;
flush += ntohs(iph->payload_len) != skb->len - hlen;
proto = iph->nexthdr;
ops = rcu_dereference(inet6_offloads[proto]);
if (!ops || !ops->callbacks.gro_receive) {
proto = ipv6_gro_pull_exthdrs(skb, hlen, proto);
ops = rcu_dereference(inet6_offloads[proto]);
if (!ops || !ops->callbacks.gro_receive)
goto out;
iph = skb_gro_network_header(skb);
} else {
skb_gro_pull(skb, sizeof(*iph));
}
skb_set_transport_header(skb, skb_gro_offset(skb));
NAPI_GRO_CB(skb)->proto = proto;
flush--;
nlen = skb_gro_offset(skb) - off;
list_for_each_entry(p, head, list) {
const struct ipv6hdr *iph2;
__be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
if (!NAPI_GRO_CB(p)->same_flow)
continue;
iph2 = (struct ipv6hdr *)(p->data + off);
first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
/* All fields must match except length and Traffic Class.
* XXX skbs on the gro_list have all been parsed and pulled
* already so we don't need to compare nlen
* (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
* memcmp() alone below is sufficient, right?
*/
if ((first_word & htonl(0xF00FFFFF)) ||
!ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
!ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
iph->nexthdr != iph2->nexthdr) {
not_same_flow:
NAPI_GRO_CB(p)->same_flow = 0;
continue;
}
if (unlikely(nlen > sizeof(struct ipv6hdr))) {
if (memcmp(iph + 1, iph2 + 1,
nlen - sizeof(struct ipv6hdr)))
goto not_same_flow;
}
}
NAPI_GRO_CB(skb)->flush |= flush;
skb_gro_postpull_rcsum(skb, iph, nlen);
pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
ops->callbacks.gro_receive, head, skb);
out:
skb_gro_flush_final(skb, pp, flush);
return pp;
}
static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
struct sk_buff *skb)
{
/* Common GRO receive for SIT and IP6IP6 */
if (NAPI_GRO_CB(skb)->encap_mark) {
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
NAPI_GRO_CB(skb)->encap_mark = 1;
return ipv6_gro_receive(head, skb);
}
static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
struct sk_buff *skb)
{
/* Common GRO receive for SIT and IP6IP6 */
if (NAPI_GRO_CB(skb)->encap_mark) {
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
NAPI_GRO_CB(skb)->encap_mark = 1;
return inet_gro_receive(head, skb);
}
INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
{
const struct net_offload *ops;
struct ipv6hdr *iph;
int err = -ENOSYS;
u32 payload_len;
if (skb->encapsulation) {
skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
skb_set_inner_network_header(skb, nhoff);
}
payload_len = skb->len - nhoff - sizeof(*iph);
if (unlikely(payload_len > IPV6_MAXPLEN)) {
struct hop_jumbo_hdr *hop_jumbo;
int hoplen = sizeof(*hop_jumbo);
/* Move network header left */
memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb),
skb->transport_header - skb->mac_header);
skb->data -= hoplen;
skb->len += hoplen;
skb->mac_header -= hoplen;
skb->network_header -= hoplen;
iph = (struct ipv6hdr *)(skb->data + nhoff);
hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1);
/* Build hop-by-hop options */
hop_jumbo->nexthdr = iph->nexthdr;
hop_jumbo->hdrlen = 0;
hop_jumbo->tlv_type = IPV6_TLV_JUMBO;
hop_jumbo->tlv_len = 4;
hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen);
iph->nexthdr = NEXTHDR_HOP;
iph->payload_len = 0;
} else {
iph = (struct ipv6hdr *)(skb->data + nhoff);
iph->payload_len = htons(payload_len);
}
nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
if (WARN_ON(!ops || !ops->callbacks.gro_complete))
goto out;
err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
udp6_gro_complete, skb, nhoff);
out:
return err;
}
static int sit_gro_complete(struct sk_buff *skb, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
return ipv6_gro_complete(skb, nhoff);
}
static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
return ipv6_gro_complete(skb, nhoff);
}
static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
return inet_gro_complete(skb, nhoff);
}
static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
return ERR_PTR(-EINVAL);
return ipv6_gso_segment(skb, features);
}
static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
return ERR_PTR(-EINVAL);
return inet_gso_segment(skb, features);
}
static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
return ERR_PTR(-EINVAL);
return ipv6_gso_segment(skb, features);
}
static const struct net_offload sit_offload = {
.callbacks = {
.gso_segment = sit_gso_segment,
.gro_receive = sit_ip6ip6_gro_receive,
.gro_complete = sit_gro_complete,
},
};
static const struct net_offload ip4ip6_offload = {
.callbacks = {
.gso_segment = ip4ip6_gso_segment,
.gro_receive = ip4ip6_gro_receive,
.gro_complete = ip4ip6_gro_complete,
},
};
static const struct net_offload ip6ip6_offload = {
.callbacks = {
.gso_segment = ip6ip6_gso_segment,
.gro_receive = sit_ip6ip6_gro_receive,
.gro_complete = ip6ip6_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 (ipv6_exthdrs_offload_init() < 0)
pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
net_hotdata.ipv6_packet_offload = (struct packet_offload) {
.type = cpu_to_be16(ETH_P_IPV6),
.callbacks = {
.gso_segment = ipv6_gso_segment,
.gro_receive = ipv6_gro_receive,
.gro_complete = ipv6_gro_complete,
},
};
dev_add_offload(&net_hotdata.ipv6_packet_offload);
inet_add_offload(&sit_offload, IPPROTO_IPV6);
inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
return 0;
}
fs_initcall(ipv6_offload_init);
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