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