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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
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
40 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
41
42 /* Set the IPv6 fragment id if not set yet */
43 if (!skb_shinfo(skb)->ip6_frag_id)
44 ipv6_proxy_select_ident(dev_net(skb->dev), skb);
45
46 segs = NULL;
47 goto out;
48 }
49
50 if (skb->encapsulation && skb_shinfo(skb)->gso_type &
51 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
52 segs = skb_udp_tunnel_segment(skb, features, true);
53 else {
54 const struct ipv6hdr *ipv6h;
55 struct udphdr *uh;
56
57 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
58 goto out;
59
60 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
61 * do checksum of UDP packets sent as multiple IP fragments.
62 */
63
64 uh = udp_hdr(skb);
65 ipv6h = ipv6_hdr(skb);
66
67 uh->check = 0;
68 csum = skb_checksum(skb, 0, skb->len, 0);
69 uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
70 &ipv6h->daddr, csum);
71 if (uh->check == 0)
72 uh->check = CSUM_MANGLED_0;
73
74 skb->ip_summed = CHECKSUM_NONE;
75
76 /* If there is no outer header we can fake a checksum offload
77 * due to the fact that we have already done the checksum in
78 * software prior to segmenting the frame.
79 */
80 if (!skb->encap_hdr_csum)
81 features |= NETIF_F_HW_CSUM;
82
83 /* Check if there is enough headroom to insert fragment header. */
84 tnl_hlen = skb_tnl_header_len(skb);
85 if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
86 if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
87 goto out;
88 }
89
90 /* Find the unfragmentable header and shift it left by frag_hdr_sz
91 * bytes to insert fragment header.
92 */
93 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
94 nexthdr = *prevhdr;
95 *prevhdr = NEXTHDR_FRAGMENT;
96 unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
97 unfrag_ip6hlen + tnl_hlen;
98 packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
99 memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);
100
101 SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
102 skb->mac_header -= frag_hdr_sz;
103 skb->network_header -= frag_hdr_sz;
104
105 fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
106 fptr->nexthdr = nexthdr;
107 fptr->reserved = 0;
108 if (!skb_shinfo(skb)->ip6_frag_id)
109 ipv6_proxy_select_ident(dev_net(skb->dev), skb);
110 fptr->identification = skb_shinfo(skb)->ip6_frag_id;
111
112 /* Fragment the skb. ipv6 header and the remaining fields of the
113 * fragment header are updated in ipv6_gso_segment()
114 */
115 segs = skb_segment(skb, features);
116 }
117
118out:
119 return segs;
120}
121
122static struct sk_buff **udp6_gro_receive(struct sk_buff **head,
123 struct sk_buff *skb)
124{
125 struct udphdr *uh = udp_gro_udphdr(skb);
126
127 if (unlikely(!uh))
128 goto flush;
129
130 /* Don't bother verifying checksum if we're going to flush anyway. */
131 if (NAPI_GRO_CB(skb)->flush)
132 goto skip;
133
134 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
135 ip6_gro_compute_pseudo))
136 goto flush;
137 else if (uh->check)
138 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
139 ip6_gro_compute_pseudo);
140
141skip:
142 NAPI_GRO_CB(skb)->is_ipv6 = 1;
143 return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb);
144
145flush:
146 NAPI_GRO_CB(skb)->flush = 1;
147 return NULL;
148}
149
150static int udp6_gro_complete(struct sk_buff *skb, int nhoff)
151{
152 const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
153 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
154
155 if (uh->check) {
156 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
157 uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr,
158 &ipv6h->daddr, 0);
159 } else {
160 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
161 }
162
163 return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb);
164}
165
166static const struct net_offload udpv6_offload = {
167 .callbacks = {
168 .gso_segment = udp6_ufo_fragment,
169 .gro_receive = udp6_gro_receive,
170 .gro_complete = udp6_gro_complete,
171 },
172};
173
174int udpv6_offload_init(void)
175{
176 return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
177}
178
179int udpv6_offload_exit(void)
180{
181 return inet6_del_offload(&udpv6_offload, IPPROTO_UDP);
182}