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 | { | |
21 | struct sk_buff *segs = ERR_PTR(-EINVAL); | |
22 | netdev_features_t enc_features; | |
b884b1a4 | 23 | int ghl; |
c50cd357 | 24 | struct gre_base_hdr *greh; |
7a7ffbab | 25 | u16 mac_offset = skb->mac_header; |
c50cd357 DB |
26 | int mac_len = skb->mac_len; |
27 | __be16 protocol = skb->protocol; | |
28 | int tnl_hlen; | |
29 | bool csum; | |
30 | ||
31 | if (unlikely(skb_shinfo(skb)->gso_type & | |
32 | ~(SKB_GSO_TCPV4 | | |
33 | SKB_GSO_TCPV6 | | |
34 | SKB_GSO_UDP | | |
35 | SKB_GSO_DODGY | | |
36 | SKB_GSO_TCP_ECN | | |
cb32f511 | 37 | SKB_GSO_GRE | |
4749c09c | 38 | SKB_GSO_GRE_CSUM | |
7e3b6e74 ED |
39 | SKB_GSO_IPIP | |
40 | SKB_GSO_SIT))) | |
c50cd357 DB |
41 | goto out; |
42 | ||
53e50398 TH |
43 | if (!skb->encapsulation) |
44 | goto out; | |
45 | ||
c50cd357 DB |
46 | if (unlikely(!pskb_may_pull(skb, sizeof(*greh)))) |
47 | goto out; | |
48 | ||
49 | greh = (struct gre_base_hdr *)skb_transport_header(skb); | |
50 | ||
14051f04 | 51 | ghl = skb_inner_mac_header(skb) - skb_transport_header(skb); |
b884b1a4 NC |
52 | if (unlikely(ghl < sizeof(*greh))) |
53 | goto out; | |
54 | ||
55 | csum = !!(greh->flags & GRE_CSUM); | |
4749c09c TH |
56 | if (csum) |
57 | skb->encap_hdr_csum = 1; | |
c50cd357 DB |
58 | |
59 | /* setup inner skb. */ | |
60 | skb->protocol = greh->protocol; | |
61 | skb->encapsulation = 0; | |
62 | ||
b4e3cef7 LR |
63 | if (unlikely(!pskb_may_pull(skb, ghl))) |
64 | goto out; | |
65 | ||
c50cd357 DB |
66 | __skb_pull(skb, ghl); |
67 | skb_reset_mac_header(skb); | |
68 | skb_set_network_header(skb, skb_inner_network_offset(skb)); | |
69 | skb->mac_len = skb_inner_network_offset(skb); | |
70 | ||
71 | /* segment inner packet. */ | |
1e16aa3d | 72 | enc_features = skb->dev->hw_enc_features & features; |
c50cd357 | 73 | segs = skb_mac_gso_segment(skb, enc_features); |
5a8dbf03 | 74 | if (IS_ERR_OR_NULL(segs)) { |
7a7ffbab | 75 | skb_gso_error_unwind(skb, protocol, ghl, mac_offset, mac_len); |
c50cd357 | 76 | goto out; |
7a7ffbab | 77 | } |
c50cd357 DB |
78 | |
79 | skb = segs; | |
80 | tnl_hlen = skb_tnl_header_len(skb); | |
81 | do { | |
82 | __skb_push(skb, ghl); | |
83 | if (csum) { | |
84 | __be32 *pcsum; | |
85 | ||
86 | if (skb_has_shared_frag(skb)) { | |
87 | int err; | |
88 | ||
89 | err = __skb_linearize(skb); | |
90 | if (err) { | |
0c1072ae | 91 | kfree_skb_list(segs); |
c50cd357 DB |
92 | segs = ERR_PTR(err); |
93 | goto out; | |
94 | } | |
95 | } | |
96 | ||
4749c09c TH |
97 | skb_reset_transport_header(skb); |
98 | ||
99 | greh = (struct gre_base_hdr *) | |
100 | skb_transport_header(skb); | |
c50cd357 DB |
101 | pcsum = (__be32 *)(greh + 1); |
102 | *pcsum = 0; | |
4749c09c | 103 | *(__sum16 *)pcsum = gso_make_checksum(skb, 0); |
c50cd357 DB |
104 | } |
105 | __skb_push(skb, tnl_hlen - ghl); | |
106 | ||
cdbaa0bb AD |
107 | skb_reset_inner_headers(skb); |
108 | skb->encapsulation = 1; | |
109 | ||
c50cd357 DB |
110 | skb_reset_mac_header(skb); |
111 | skb_set_network_header(skb, mac_len); | |
112 | skb->mac_len = mac_len; | |
113 | skb->protocol = protocol; | |
114 | } while ((skb = skb->next)); | |
115 | out: | |
116 | return segs; | |
117 | } | |
118 | ||
bf5a755f JC |
119 | static struct sk_buff **gre_gro_receive(struct sk_buff **head, |
120 | struct sk_buff *skb) | |
121 | { | |
122 | struct sk_buff **pp = NULL; | |
123 | struct sk_buff *p; | |
124 | const struct gre_base_hdr *greh; | |
125 | unsigned int hlen, grehlen; | |
126 | unsigned int off; | |
127 | int flush = 1; | |
128 | struct packet_offload *ptype; | |
129 | __be16 type; | |
130 | ||
5699b343 JG |
131 | if (NAPI_GRO_CB(skb)->encap_mark) |
132 | goto out; | |
133 | ||
134 | NAPI_GRO_CB(skb)->encap_mark = 1; | |
135 | ||
bf5a755f JC |
136 | off = skb_gro_offset(skb); |
137 | hlen = off + sizeof(*greh); | |
138 | greh = skb_gro_header_fast(skb, off); | |
139 | if (skb_gro_header_hard(skb, hlen)) { | |
140 | greh = skb_gro_header_slow(skb, hlen, off); | |
141 | if (unlikely(!greh)) | |
142 | goto out; | |
143 | } | |
144 | ||
145 | /* Only support version 0 and K (key), C (csum) flags. Note that | |
146 | * although the support for the S (seq#) flag can be added easily | |
147 | * for GRO, this is problematic for GSO hence can not be enabled | |
148 | * here because a GRO pkt may end up in the forwarding path, thus | |
149 | * requiring GSO support to break it up correctly. | |
150 | */ | |
151 | if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0) | |
152 | goto out; | |
153 | ||
154 | type = greh->protocol; | |
155 | ||
156 | rcu_read_lock(); | |
157 | ptype = gro_find_receive_by_type(type); | |
51456b29 | 158 | if (!ptype) |
bf5a755f JC |
159 | goto out_unlock; |
160 | ||
161 | grehlen = GRE_HEADER_SECTION; | |
162 | ||
163 | if (greh->flags & GRE_KEY) | |
164 | grehlen += GRE_HEADER_SECTION; | |
165 | ||
166 | if (greh->flags & GRE_CSUM) | |
167 | grehlen += GRE_HEADER_SECTION; | |
168 | ||
169 | hlen = off + grehlen; | |
170 | if (skb_gro_header_hard(skb, hlen)) { | |
171 | greh = skb_gro_header_slow(skb, hlen, off); | |
172 | if (unlikely(!greh)) | |
173 | goto out_unlock; | |
174 | } | |
758f75d1 TH |
175 | |
176 | /* Don't bother verifying checksum if we're going to flush anyway. */ | |
884d338c TH |
177 | if ((greh->flags & GRE_CSUM) && !NAPI_GRO_CB(skb)->flush) { |
178 | if (skb_gro_checksum_simple_validate(skb)) | |
bf5a755f | 179 | goto out_unlock; |
758f75d1 | 180 | |
884d338c TH |
181 | skb_gro_checksum_try_convert(skb, IPPROTO_GRE, 0, |
182 | null_compute_pseudo); | |
183 | } | |
184 | ||
bf5a755f JC |
185 | flush = 0; |
186 | ||
187 | for (p = *head; p; p = p->next) { | |
188 | const struct gre_base_hdr *greh2; | |
189 | ||
190 | if (!NAPI_GRO_CB(p)->same_flow) | |
191 | continue; | |
192 | ||
193 | /* The following checks are needed to ensure only pkts | |
194 | * from the same tunnel are considered for aggregation. | |
195 | * The criteria for "the same tunnel" includes: | |
196 | * 1) same version (we only support version 0 here) | |
197 | * 2) same protocol (we only support ETH_P_IP for now) | |
198 | * 3) same set of flags | |
199 | * 4) same key if the key field is present. | |
200 | */ | |
201 | greh2 = (struct gre_base_hdr *)(p->data + off); | |
202 | ||
203 | if (greh2->flags != greh->flags || | |
204 | greh2->protocol != greh->protocol) { | |
205 | NAPI_GRO_CB(p)->same_flow = 0; | |
206 | continue; | |
207 | } | |
208 | if (greh->flags & GRE_KEY) { | |
209 | /* compare keys */ | |
210 | if (*(__be32 *)(greh2+1) != *(__be32 *)(greh+1)) { | |
211 | NAPI_GRO_CB(p)->same_flow = 0; | |
212 | continue; | |
213 | } | |
214 | } | |
215 | } | |
216 | ||
217 | skb_gro_pull(skb, grehlen); | |
218 | ||
219 | /* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/ | |
220 | skb_gro_postpull_rcsum(skb, greh, grehlen); | |
221 | ||
3cb00b90 | 222 | pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb); |
bf5a755f JC |
223 | |
224 | out_unlock: | |
225 | rcu_read_unlock(); | |
226 | out: | |
227 | NAPI_GRO_CB(skb)->flush |= flush; | |
228 | ||
229 | return pp; | |
230 | } | |
231 | ||
d10dbad2 | 232 | static int gre_gro_complete(struct sk_buff *skb, int nhoff) |
bf5a755f JC |
233 | { |
234 | struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff); | |
235 | struct packet_offload *ptype; | |
236 | unsigned int grehlen = sizeof(*greh); | |
237 | int err = -ENOENT; | |
238 | __be16 type; | |
239 | ||
c3caf119 JC |
240 | skb->encapsulation = 1; |
241 | skb_shinfo(skb)->gso_type = SKB_GSO_GRE; | |
242 | ||
bf5a755f JC |
243 | type = greh->protocol; |
244 | if (greh->flags & GRE_KEY) | |
245 | grehlen += GRE_HEADER_SECTION; | |
246 | ||
247 | if (greh->flags & GRE_CSUM) | |
248 | grehlen += GRE_HEADER_SECTION; | |
249 | ||
250 | rcu_read_lock(); | |
251 | ptype = gro_find_complete_by_type(type); | |
00db4124 | 252 | if (ptype) |
bf5a755f JC |
253 | err = ptype->callbacks.gro_complete(skb, nhoff + grehlen); |
254 | ||
255 | rcu_read_unlock(); | |
6fb2a756 TH |
256 | |
257 | skb_set_inner_mac_header(skb, nhoff + grehlen); | |
258 | ||
bf5a755f JC |
259 | return err; |
260 | } | |
261 | ||
c50cd357 DB |
262 | static const struct net_offload gre_offload = { |
263 | .callbacks = { | |
c50cd357 | 264 | .gso_segment = gre_gso_segment, |
bf5a755f JC |
265 | .gro_receive = gre_gro_receive, |
266 | .gro_complete = gre_gro_complete, | |
c50cd357 DB |
267 | }, |
268 | }; | |
269 | ||
438e38fa | 270 | static int __init gre_offload_init(void) |
c50cd357 DB |
271 | { |
272 | return inet_add_offload(&gre_offload, IPPROTO_GRE); | |
273 | } | |
cf172283 | 274 | device_initcall(gre_offload_init); |