2 * IPV4 GSO/GRO offload support
3 * Linux INET implementation
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
13 #include <linux/skbuff.h>
15 #include <net/protocol.h>
17 static DEFINE_SPINLOCK(udp_offload_lock
);
18 static struct udp_offload_priv __rcu
*udp_offload_base __read_mostly
;
20 #define udp_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&udp_offload_lock))
22 struct udp_offload_priv
{
23 struct udp_offload
*offload
;
25 struct udp_offload_priv __rcu
*next
;
28 static int udp4_ufo_send_check(struct sk_buff
*skb
)
30 if (!pskb_may_pull(skb
, sizeof(struct udphdr
)))
33 if (likely(!skb
->encapsulation
)) {
34 const struct iphdr
*iph
;
40 uh
->check
= ~csum_tcpudp_magic(iph
->saddr
, iph
->daddr
, skb
->len
,
42 skb
->csum_start
= skb_transport_header(skb
) - skb
->head
;
43 skb
->csum_offset
= offsetof(struct udphdr
, check
);
44 skb
->ip_summed
= CHECKSUM_PARTIAL
;
50 static struct sk_buff
*udp4_ufo_fragment(struct sk_buff
*skb
,
51 netdev_features_t features
)
53 struct sk_buff
*segs
= ERR_PTR(-EINVAL
);
58 if (skb
->encapsulation
&&
59 (skb_shinfo(skb
)->gso_type
&
60 (SKB_GSO_UDP_TUNNEL
|SKB_GSO_UDP_TUNNEL_CSUM
))) {
61 segs
= skb_udp_tunnel_segment(skb
, features
);
65 mss
= skb_shinfo(skb
)->gso_size
;
66 if (unlikely(skb
->len
<= mss
))
69 if (skb_gso_ok(skb
, features
| NETIF_F_GSO_ROBUST
)) {
70 /* Packet is from an untrusted source, reset gso_segs. */
71 int type
= skb_shinfo(skb
)->gso_type
;
73 if (unlikely(type
& ~(SKB_GSO_UDP
| SKB_GSO_DODGY
|
75 SKB_GSO_UDP_TUNNEL_CSUM
|
77 SKB_GSO_GRE
| SKB_GSO_MPLS
) ||
78 !(type
& (SKB_GSO_UDP
))))
81 skb_shinfo(skb
)->gso_segs
= DIV_ROUND_UP(skb
->len
, mss
);
87 /* Do software UFO. Complete and fill in the UDP checksum as
88 * HW cannot do checksum of UDP packets sent as multiple
91 offset
= skb_checksum_start_offset(skb
);
92 csum
= skb_checksum(skb
, offset
, skb
->len
- offset
, 0);
93 offset
+= skb
->csum_offset
;
94 *(__sum16
*)(skb
->data
+ offset
) = csum_fold(csum
);
95 skb
->ip_summed
= CHECKSUM_NONE
;
97 /* Fragment the skb. IP headers of the fragments are updated in
100 segs
= skb_segment(skb
, features
);
105 int udp_add_offload(struct udp_offload
*uo
)
107 struct udp_offload_priv
*new_offload
= kzalloc(sizeof(*new_offload
), GFP_ATOMIC
);
112 new_offload
->offload
= uo
;
114 spin_lock(&udp_offload_lock
);
115 new_offload
->next
= udp_offload_base
;
116 rcu_assign_pointer(udp_offload_base
, new_offload
);
117 spin_unlock(&udp_offload_lock
);
121 EXPORT_SYMBOL(udp_add_offload
);
123 static void udp_offload_free_routine(struct rcu_head
*head
)
125 struct udp_offload_priv
*ou_priv
= container_of(head
, struct udp_offload_priv
, rcu
);
129 void udp_del_offload(struct udp_offload
*uo
)
131 struct udp_offload_priv __rcu
**head
= &udp_offload_base
;
132 struct udp_offload_priv
*uo_priv
;
134 spin_lock(&udp_offload_lock
);
136 uo_priv
= udp_deref_protected(*head
);
137 for (; uo_priv
!= NULL
;
138 uo_priv
= udp_deref_protected(*head
)) {
139 if (uo_priv
->offload
== uo
) {
140 rcu_assign_pointer(*head
,
141 udp_deref_protected(uo_priv
->next
));
144 head
= &uo_priv
->next
;
146 pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo
->port
));
148 spin_unlock(&udp_offload_lock
);
150 call_rcu(&uo_priv
->rcu
, udp_offload_free_routine
);
152 EXPORT_SYMBOL(udp_del_offload
);
154 static struct sk_buff
**udp_gro_receive(struct sk_buff
**head
, struct sk_buff
*skb
)
156 struct udp_offload_priv
*uo_priv
;
157 struct sk_buff
*p
, **pp
= NULL
;
158 struct udphdr
*uh
, *uh2
;
159 unsigned int hlen
, off
;
162 if (NAPI_GRO_CB(skb
)->udp_mark
||
163 (!skb
->encapsulation
&& skb
->ip_summed
!= CHECKSUM_COMPLETE
))
166 /* mark that this skb passed once through the udp gro layer */
167 NAPI_GRO_CB(skb
)->udp_mark
= 1;
169 off
= skb_gro_offset(skb
);
170 hlen
= off
+ sizeof(*uh
);
171 uh
= skb_gro_header_fast(skb
, off
);
172 if (skb_gro_header_hard(skb
, hlen
)) {
173 uh
= skb_gro_header_slow(skb
, hlen
, off
);
179 uo_priv
= rcu_dereference(udp_offload_base
);
180 for (; uo_priv
!= NULL
; uo_priv
= rcu_dereference(uo_priv
->next
)) {
181 if (uo_priv
->offload
->port
== uh
->dest
&&
182 uo_priv
->offload
->callbacks
.gro_receive
)
190 for (p
= *head
; p
; p
= p
->next
) {
191 if (!NAPI_GRO_CB(p
)->same_flow
)
194 uh2
= (struct udphdr
*)(p
->data
+ off
);
195 if ((*(u32
*)&uh
->source
!= *(u32
*)&uh2
->source
)) {
196 NAPI_GRO_CB(p
)->same_flow
= 0;
201 skb_gro_pull(skb
, sizeof(struct udphdr
)); /* pull encapsulating udp header */
202 pp
= uo_priv
->offload
->callbacks
.gro_receive(head
, skb
);
207 NAPI_GRO_CB(skb
)->flush
|= flush
;
211 static int udp_gro_complete(struct sk_buff
*skb
, int nhoff
)
213 struct udp_offload_priv
*uo_priv
;
214 __be16 newlen
= htons(skb
->len
- nhoff
);
215 struct udphdr
*uh
= (struct udphdr
*)(skb
->data
+ nhoff
);
222 uo_priv
= rcu_dereference(udp_offload_base
);
223 for (; uo_priv
!= NULL
; uo_priv
= rcu_dereference(uo_priv
->next
)) {
224 if (uo_priv
->offload
->port
== uh
->dest
&&
225 uo_priv
->offload
->callbacks
.gro_complete
)
230 err
= uo_priv
->offload
->callbacks
.gro_complete(skb
, nhoff
+ sizeof(struct udphdr
));
236 static const struct net_offload udpv4_offload
= {
238 .gso_send_check
= udp4_ufo_send_check
,
239 .gso_segment
= udp4_ufo_fragment
,
240 .gro_receive
= udp_gro_receive
,
241 .gro_complete
= udp_gro_complete
,
245 int __init
udpv4_offload_init(void)
247 return inet_add_offload(&udpv4_offload
, IPPROTO_UDP
);