Commit | Line | Data |
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c50cd357 DB |
1 | /* |
2 | * IPV4 GSO/GRO offload support | |
3 | * Linux INET 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 | * GRE GSO support | |
11 | */ | |
12 | ||
13 | #include <linux/skbuff.h> | |
cf172283 | 14 | #include <linux/init.h> |
c50cd357 DB |
15 | #include <net/protocol.h> |
16 | #include <net/gre.h> | |
17 | ||
c50cd357 DB |
18 | static struct sk_buff *gre_gso_segment(struct sk_buff *skb, |
19 | netdev_features_t features) | |
20 | { | |
2e598af7 | 21 | int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); |
c50cd357 | 22 | struct sk_buff *segs = ERR_PTR(-EINVAL); |
7a7ffbab | 23 | u16 mac_offset = skb->mac_header; |
c50cd357 | 24 | __be16 protocol = skb->protocol; |
2e598af7 AD |
25 | u16 mac_len = skb->mac_len; |
26 | int gre_offset, outer_hlen; | |
22463876 | 27 | bool need_csum, ufo; |
c50cd357 DB |
28 | |
29 | if (unlikely(skb_shinfo(skb)->gso_type & | |
30 | ~(SKB_GSO_TCPV4 | | |
31 | SKB_GSO_TCPV6 | | |
32 | SKB_GSO_UDP | | |
33 | SKB_GSO_DODGY | | |
34 | SKB_GSO_TCP_ECN | | |
cb32f511 | 35 | SKB_GSO_GRE | |
4749c09c | 36 | SKB_GSO_GRE_CSUM | |
7e3b6e74 ED |
37 | SKB_GSO_IPIP | |
38 | SKB_GSO_SIT))) | |
c50cd357 DB |
39 | goto out; |
40 | ||
53e50398 TH |
41 | if (!skb->encapsulation) |
42 | goto out; | |
43 | ||
2e598af7 | 44 | if (unlikely(tnl_hlen < sizeof(struct gre_base_hdr))) |
c50cd357 DB |
45 | goto out; |
46 | ||
2e598af7 | 47 | if (unlikely(!pskb_may_pull(skb, tnl_hlen))) |
b884b1a4 NC |
48 | goto out; |
49 | ||
c50cd357 | 50 | /* setup inner skb. */ |
c50cd357 | 51 | skb->encapsulation = 0; |
5197f349 | 52 | SKB_GSO_CB(skb)->encap_level = 0; |
2e598af7 | 53 | __skb_pull(skb, tnl_hlen); |
c50cd357 DB |
54 | skb_reset_mac_header(skb); |
55 | skb_set_network_header(skb, skb_inner_network_offset(skb)); | |
56 | skb->mac_len = skb_inner_network_offset(skb); | |
38720352 | 57 | skb->protocol = skb->inner_protocol; |
c50cd357 | 58 | |
2e598af7 AD |
59 | need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM); |
60 | skb->encap_hdr_csum = need_csum; | |
61 | ||
22463876 AD |
62 | ufo = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP); |
63 | ||
bef3c6c9 AD |
64 | features &= skb->dev->hw_enc_features; |
65 | ||
22463876 AD |
66 | /* The only checksum offload we care about from here on out is the |
67 | * outer one so strip the existing checksum feature flags based | |
68 | * on the fact that we will be computing our checksum in software. | |
69 | */ | |
70 | if (ufo) { | |
71 | features &= ~NETIF_F_CSUM_MASK; | |
72 | if (!need_csum) | |
73 | features |= NETIF_F_HW_CSUM; | |
74 | } | |
75 | ||
c50cd357 | 76 | /* segment inner packet. */ |
bef3c6c9 | 77 | segs = skb_mac_gso_segment(skb, features); |
5a8dbf03 | 78 | if (IS_ERR_OR_NULL(segs)) { |
2e598af7 AD |
79 | skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset, |
80 | mac_len); | |
c50cd357 | 81 | goto out; |
7a7ffbab | 82 | } |
c50cd357 | 83 | |
2e598af7 AD |
84 | outer_hlen = skb_tnl_header_len(skb); |
85 | gre_offset = outer_hlen - tnl_hlen; | |
c50cd357 | 86 | skb = segs; |
c50cd357 | 87 | do { |
38720352 | 88 | struct gre_base_hdr *greh; |
2e598af7 | 89 | __be32 *pcsum; |
c50cd357 | 90 | |
22463876 AD |
91 | /* Set up inner headers if we are offloading inner checksum */ |
92 | if (skb->ip_summed == CHECKSUM_PARTIAL) { | |
93 | skb_reset_inner_headers(skb); | |
94 | skb->encapsulation = 1; | |
95 | } | |
cdbaa0bb | 96 | |
c50cd357 DB |
97 | skb->mac_len = mac_len; |
98 | skb->protocol = protocol; | |
2e598af7 AD |
99 | |
100 | __skb_push(skb, outer_hlen); | |
101 | skb_reset_mac_header(skb); | |
102 | skb_set_network_header(skb, mac_len); | |
103 | skb_set_transport_header(skb, gre_offset); | |
104 | ||
105 | if (!need_csum) | |
106 | continue; | |
107 | ||
108 | greh = (struct gre_base_hdr *)skb_transport_header(skb); | |
109 | pcsum = (__be32 *)(greh + 1); | |
110 | ||
111 | *pcsum = 0; | |
112 | *(__sum16 *)pcsum = gso_make_checksum(skb, 0); | |
c50cd357 DB |
113 | } while ((skb = skb->next)); |
114 | out: | |
115 | return segs; | |
116 | } | |
117 | ||
bf5a755f JC |
118 | static struct sk_buff **gre_gro_receive(struct sk_buff **head, |
119 | struct sk_buff *skb) | |
120 | { | |
121 | struct sk_buff **pp = NULL; | |
122 | struct sk_buff *p; | |
123 | const struct gre_base_hdr *greh; | |
124 | unsigned int hlen, grehlen; | |
125 | unsigned int off; | |
126 | int flush = 1; | |
127 | struct packet_offload *ptype; | |
128 | __be16 type; | |
129 | ||
fac8e0f5 JG |
130 | if (NAPI_GRO_CB(skb)->encap_mark) |
131 | goto out; | |
132 | ||
133 | NAPI_GRO_CB(skb)->encap_mark = 1; | |
134 | ||
bf5a755f JC |
135 | off = skb_gro_offset(skb); |
136 | hlen = off + sizeof(*greh); | |
137 | greh = skb_gro_header_fast(skb, off); | |
138 | if (skb_gro_header_hard(skb, hlen)) { | |
139 | greh = skb_gro_header_slow(skb, hlen, off); | |
140 | if (unlikely(!greh)) | |
141 | goto out; | |
142 | } | |
143 | ||
144 | /* Only support version 0 and K (key), C (csum) flags. Note that | |
145 | * although the support for the S (seq#) flag can be added easily | |
146 | * for GRO, this is problematic for GSO hence can not be enabled | |
147 | * here because a GRO pkt may end up in the forwarding path, thus | |
148 | * requiring GSO support to break it up correctly. | |
149 | */ | |
150 | if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0) | |
151 | goto out; | |
152 | ||
a0ca153f AD |
153 | /* We can only support GRE_CSUM if we can track the location of |
154 | * the GRE header. In the case of FOU/GUE we cannot because the | |
155 | * outer UDP header displaces the GRE header leaving us in a state | |
156 | * of limbo. | |
157 | */ | |
158 | if ((greh->flags & GRE_CSUM) && NAPI_GRO_CB(skb)->is_fou) | |
159 | goto out; | |
160 | ||
bf5a755f JC |
161 | type = greh->protocol; |
162 | ||
163 | rcu_read_lock(); | |
164 | ptype = gro_find_receive_by_type(type); | |
51456b29 | 165 | if (!ptype) |
bf5a755f JC |
166 | goto out_unlock; |
167 | ||
168 | grehlen = GRE_HEADER_SECTION; | |
169 | ||
170 | if (greh->flags & GRE_KEY) | |
171 | grehlen += GRE_HEADER_SECTION; | |
172 | ||
173 | if (greh->flags & GRE_CSUM) | |
174 | grehlen += GRE_HEADER_SECTION; | |
175 | ||
176 | hlen = off + grehlen; | |
177 | if (skb_gro_header_hard(skb, hlen)) { | |
178 | greh = skb_gro_header_slow(skb, hlen, off); | |
179 | if (unlikely(!greh)) | |
180 | goto out_unlock; | |
181 | } | |
758f75d1 TH |
182 | |
183 | /* Don't bother verifying checksum if we're going to flush anyway. */ | |
884d338c TH |
184 | if ((greh->flags & GRE_CSUM) && !NAPI_GRO_CB(skb)->flush) { |
185 | if (skb_gro_checksum_simple_validate(skb)) | |
bf5a755f | 186 | goto out_unlock; |
758f75d1 | 187 | |
884d338c TH |
188 | skb_gro_checksum_try_convert(skb, IPPROTO_GRE, 0, |
189 | null_compute_pseudo); | |
190 | } | |
191 | ||
bf5a755f JC |
192 | for (p = *head; p; p = p->next) { |
193 | const struct gre_base_hdr *greh2; | |
194 | ||
195 | if (!NAPI_GRO_CB(p)->same_flow) | |
196 | continue; | |
197 | ||
198 | /* The following checks are needed to ensure only pkts | |
199 | * from the same tunnel are considered for aggregation. | |
200 | * The criteria for "the same tunnel" includes: | |
201 | * 1) same version (we only support version 0 here) | |
202 | * 2) same protocol (we only support ETH_P_IP for now) | |
203 | * 3) same set of flags | |
204 | * 4) same key if the key field is present. | |
205 | */ | |
206 | greh2 = (struct gre_base_hdr *)(p->data + off); | |
207 | ||
208 | if (greh2->flags != greh->flags || | |
209 | greh2->protocol != greh->protocol) { | |
210 | NAPI_GRO_CB(p)->same_flow = 0; | |
211 | continue; | |
212 | } | |
213 | if (greh->flags & GRE_KEY) { | |
214 | /* compare keys */ | |
215 | if (*(__be32 *)(greh2+1) != *(__be32 *)(greh+1)) { | |
216 | NAPI_GRO_CB(p)->same_flow = 0; | |
217 | continue; | |
218 | } | |
219 | } | |
220 | } | |
221 | ||
222 | skb_gro_pull(skb, grehlen); | |
223 | ||
224 | /* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/ | |
225 | skb_gro_postpull_rcsum(skb, greh, grehlen); | |
226 | ||
227 | pp = ptype->callbacks.gro_receive(head, skb); | |
c194cf93 | 228 | flush = 0; |
bf5a755f JC |
229 | |
230 | out_unlock: | |
231 | rcu_read_unlock(); | |
232 | out: | |
233 | NAPI_GRO_CB(skb)->flush |= flush; | |
234 | ||
235 | return pp; | |
236 | } | |
237 | ||
d10dbad2 | 238 | static int gre_gro_complete(struct sk_buff *skb, int nhoff) |
bf5a755f JC |
239 | { |
240 | struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff); | |
241 | struct packet_offload *ptype; | |
242 | unsigned int grehlen = sizeof(*greh); | |
243 | int err = -ENOENT; | |
244 | __be16 type; | |
245 | ||
c3caf119 JC |
246 | skb->encapsulation = 1; |
247 | skb_shinfo(skb)->gso_type = SKB_GSO_GRE; | |
248 | ||
bf5a755f JC |
249 | type = greh->protocol; |
250 | if (greh->flags & GRE_KEY) | |
251 | grehlen += GRE_HEADER_SECTION; | |
252 | ||
253 | if (greh->flags & GRE_CSUM) | |
254 | grehlen += GRE_HEADER_SECTION; | |
255 | ||
256 | rcu_read_lock(); | |
257 | ptype = gro_find_complete_by_type(type); | |
00db4124 | 258 | if (ptype) |
bf5a755f JC |
259 | err = ptype->callbacks.gro_complete(skb, nhoff + grehlen); |
260 | ||
261 | rcu_read_unlock(); | |
6fb2a756 TH |
262 | |
263 | skb_set_inner_mac_header(skb, nhoff + grehlen); | |
264 | ||
bf5a755f JC |
265 | return err; |
266 | } | |
267 | ||
c50cd357 DB |
268 | static const struct net_offload gre_offload = { |
269 | .callbacks = { | |
c50cd357 | 270 | .gso_segment = gre_gso_segment, |
bf5a755f JC |
271 | .gro_receive = gre_gro_receive, |
272 | .gro_complete = gre_gro_complete, | |
c50cd357 DB |
273 | }, |
274 | }; | |
275 | ||
438e38fa | 276 | static int __init gre_offload_init(void) |
c50cd357 DB |
277 | { |
278 | return inet_add_offload(&gre_offload, IPPROTO_GRE); | |
279 | } | |
cf172283 | 280 | device_initcall(gre_offload_init); |