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1/*
2 * IPV6 GSO/GRO offload support
3 * Linux INET6 implementation
4 *
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.
9 *
10 * UDPv6 GSO support
11 */
12#include <linux/skbuff.h>
13#include <linux/netdevice.h>
14#include <net/protocol.h>
15#include <net/ipv6.h>
16#include <net/udp.h>
17#include <net/ip6_checksum.h>
18#include "ip6_offload.h"
19
20static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
21 netdev_features_t features)
22{
23 struct sk_buff *segs = ERR_PTR(-EINVAL);
24 unsigned int mss;
25 unsigned int unfrag_ip6hlen, unfrag_len;
26 struct frag_hdr *fptr;
27 u8 *packet_start, *prevhdr;
28 u8 nexthdr;
29 u8 frag_hdr_sz = sizeof(struct frag_hdr);
30 __wsum csum;
31 int tnl_hlen;
32
33 mss = skb_shinfo(skb)->gso_size;
34 if (unlikely(skb->len <= mss))
35 goto out;
36
37 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
38 /* Packet is from an untrusted source, reset gso_segs. */
39 int type = skb_shinfo(skb)->gso_type;
40
41 if (unlikely(type & ~(SKB_GSO_UDP |
42 SKB_GSO_DODGY |
43 SKB_GSO_UDP_TUNNEL |
44 SKB_GSO_UDP_TUNNEL_CSUM |
45 SKB_GSO_TUNNEL_REMCSUM |
46 SKB_GSO_GRE |
47 SKB_GSO_GRE_CSUM |
48 SKB_GSO_IPIP |
49 SKB_GSO_SIT) ||
50 !(type & (SKB_GSO_UDP))))
51 goto out;
52
53 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
54
55 /* Set the IPv6 fragment id if not set yet */
56 if (!skb_shinfo(skb)->ip6_frag_id)
57 ipv6_proxy_select_ident(dev_net(skb->dev), skb);
58
59 segs = NULL;
60 goto out;
61 }
62
63 if (skb->encapsulation && skb_shinfo(skb)->gso_type &
64 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
65 segs = skb_udp_tunnel_segment(skb, features, true);
66 else {
67 const struct ipv6hdr *ipv6h;
68 struct udphdr *uh;
69
70 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
71 goto out;
72
73 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
74 * do checksum of UDP packets sent as multiple IP fragments.
75 */
76
77 uh = udp_hdr(skb);
78 ipv6h = ipv6_hdr(skb);
79
80 uh->check = 0;
81 csum = skb_checksum(skb, 0, skb->len, 0);
82 uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
83 &ipv6h->daddr, csum);
84 if (uh->check == 0)
85 uh->check = CSUM_MANGLED_0;
86
87 skb->ip_summed = CHECKSUM_NONE;
88
89 /* If there is no outer header we can fake a checksum offload
90 * due to the fact that we have already done the checksum in
91 * software prior to segmenting the frame.
92 */
93 if (!skb->encap_hdr_csum)
94 features |= NETIF_F_HW_CSUM;
95
96 /* Check if there is enough headroom to insert fragment header. */
97 tnl_hlen = skb_tnl_header_len(skb);
98 if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
99 if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
100 goto out;
101 }
102
103 /* Find the unfragmentable header and shift it left by frag_hdr_sz
104 * bytes to insert fragment header.
105 */
106 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
107 nexthdr = *prevhdr;
108 *prevhdr = NEXTHDR_FRAGMENT;
109 unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
110 unfrag_ip6hlen + tnl_hlen;
111 packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
112 memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);
113
114 SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
115 skb->mac_header -= frag_hdr_sz;
116 skb->network_header -= frag_hdr_sz;
117
118 fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
119 fptr->nexthdr = nexthdr;
120 fptr->reserved = 0;
121 if (!skb_shinfo(skb)->ip6_frag_id)
122 ipv6_proxy_select_ident(dev_net(skb->dev), skb);
123 fptr->identification = skb_shinfo(skb)->ip6_frag_id;
124
125 /* Fragment the skb. ipv6 header and the remaining fields of the
126 * fragment header are updated in ipv6_gso_segment()
127 */
128 segs = skb_segment(skb, features);
129 }
130
131out:
132 return segs;
133}
134
135static struct sk_buff **udp6_gro_receive(struct sk_buff **head,
136 struct sk_buff *skb)
137{
138 struct udphdr *uh = udp_gro_udphdr(skb);
139
140 if (unlikely(!uh))
141 goto flush;
142
143 /* Don't bother verifying checksum if we're going to flush anyway. */
144 if (NAPI_GRO_CB(skb)->flush)
145 goto skip;
146
147 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
148 ip6_gro_compute_pseudo))
149 goto flush;
150 else if (uh->check)
151 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
152 ip6_gro_compute_pseudo);
153
154skip:
155 NAPI_GRO_CB(skb)->is_ipv6 = 1;
156 return udp_gro_receive(head, skb, uh);
157
158flush:
159 NAPI_GRO_CB(skb)->flush = 1;
160 return NULL;
161}
162
163static int udp6_gro_complete(struct sk_buff *skb, int nhoff)
164{
165 const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
166 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
167
168 if (uh->check) {
169 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
170 uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr,
171 &ipv6h->daddr, 0);
172 } else {
173 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
174 }
175
176 return udp_gro_complete(skb, nhoff);
177}
178
179static const struct net_offload udpv6_offload = {
180 .callbacks = {
181 .gso_segment = udp6_ufo_fragment,
182 .gro_receive = udp6_gro_receive,
183 .gro_complete = udp6_gro_complete,
184 },
185};
186
187int __init udp_offload_init(void)
188{
189 return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
190}
1/*
2 * IPV6 GSO/GRO offload support
3 * Linux INET6 implementation
4 *
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.
9 *
10 * UDPv6 GSO support
11 */
12#include <linux/skbuff.h>
13#include <linux/netdevice.h>
14#include <net/protocol.h>
15#include <net/ipv6.h>
16#include <net/udp.h>
17#include <net/ip6_checksum.h>
18#include "ip6_offload.h"
19
20static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
21 netdev_features_t features)
22{
23 struct sk_buff *segs = ERR_PTR(-EINVAL);
24 unsigned int mss;
25 unsigned int unfrag_ip6hlen, unfrag_len;
26 struct frag_hdr *fptr;
27 u8 *packet_start, *prevhdr;
28 u8 nexthdr;
29 u8 frag_hdr_sz = sizeof(struct frag_hdr);
30 __wsum csum;
31 int tnl_hlen;
32 int err;
33
34 mss = skb_shinfo(skb)->gso_size;
35 if (unlikely(skb->len <= mss))
36 goto out;
37
38 if (skb->encapsulation && skb_shinfo(skb)->gso_type &
39 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
40 segs = skb_udp_tunnel_segment(skb, features, true);
41 else {
42 const struct ipv6hdr *ipv6h;
43 struct udphdr *uh;
44
45 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
46 goto out;
47
48 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
49 goto out;
50
51 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
52 * do checksum of UDP packets sent as multiple IP fragments.
53 */
54
55 uh = udp_hdr(skb);
56 ipv6h = ipv6_hdr(skb);
57
58 uh->check = 0;
59 csum = skb_checksum(skb, 0, skb->len, 0);
60 uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
61 &ipv6h->daddr, csum);
62 if (uh->check == 0)
63 uh->check = CSUM_MANGLED_0;
64
65 skb->ip_summed = CHECKSUM_UNNECESSARY;
66
67 /* If there is no outer header we can fake a checksum offload
68 * due to the fact that we have already done the checksum in
69 * software prior to segmenting the frame.
70 */
71 if (!skb->encap_hdr_csum)
72 features |= NETIF_F_HW_CSUM;
73
74 /* Check if there is enough headroom to insert fragment header. */
75 tnl_hlen = skb_tnl_header_len(skb);
76 if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
77 if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
78 goto out;
79 }
80
81 /* Find the unfragmentable header and shift it left by frag_hdr_sz
82 * bytes to insert fragment header.
83 */
84 err = ip6_find_1stfragopt(skb, &prevhdr);
85 if (err < 0)
86 return ERR_PTR(err);
87 unfrag_ip6hlen = err;
88 nexthdr = *prevhdr;
89 *prevhdr = NEXTHDR_FRAGMENT;
90 unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
91 unfrag_ip6hlen + tnl_hlen;
92 packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
93 memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);
94
95 SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
96 skb->mac_header -= frag_hdr_sz;
97 skb->network_header -= frag_hdr_sz;
98
99 fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
100 fptr->nexthdr = nexthdr;
101 fptr->reserved = 0;
102 fptr->identification = ipv6_proxy_select_ident(dev_net(skb->dev), skb);
103
104 /* Fragment the skb. ipv6 header and the remaining fields of the
105 * fragment header are updated in ipv6_gso_segment()
106 */
107 segs = skb_segment(skb, features);
108 }
109
110out:
111 return segs;
112}
113
114static struct sk_buff **udp6_gro_receive(struct sk_buff **head,
115 struct sk_buff *skb)
116{
117 struct udphdr *uh = udp_gro_udphdr(skb);
118
119 if (unlikely(!uh))
120 goto flush;
121
122 /* Don't bother verifying checksum if we're going to flush anyway. */
123 if (NAPI_GRO_CB(skb)->flush)
124 goto skip;
125
126 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
127 ip6_gro_compute_pseudo))
128 goto flush;
129 else if (uh->check)
130 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
131 ip6_gro_compute_pseudo);
132
133skip:
134 NAPI_GRO_CB(skb)->is_ipv6 = 1;
135 return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb);
136
137flush:
138 NAPI_GRO_CB(skb)->flush = 1;
139 return NULL;
140}
141
142static int udp6_gro_complete(struct sk_buff *skb, int nhoff)
143{
144 const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
145 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
146
147 if (uh->check) {
148 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
149 uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr,
150 &ipv6h->daddr, 0);
151 } else {
152 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
153 }
154
155 return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb);
156}
157
158static const struct net_offload udpv6_offload = {
159 .callbacks = {
160 .gso_segment = udp6_ufo_fragment,
161 .gro_receive = udp6_gro_receive,
162 .gro_complete = udp6_gro_complete,
163 },
164};
165
166int udpv6_offload_init(void)
167{
168 return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
169}
170
171int udpv6_offload_exit(void)
172{
173 return inet6_del_offload(&udpv6_offload, IPPROTO_UDP);
174}