Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
c50cd357 DB |
2 | /* |
3 | * IPV4 GSO/GRO offload support | |
4 | * Linux INET implementation | |
5 | * | |
c50cd357 DB |
6 | * GRE GSO support |
7 | */ | |
8 | ||
9 | #include <linux/skbuff.h> | |
cf172283 | 10 | #include <linux/init.h> |
c50cd357 DB |
11 | #include <net/protocol.h> |
12 | #include <net/gre.h> | |
13 | ||
c50cd357 DB |
14 | static struct sk_buff *gre_gso_segment(struct sk_buff *skb, |
15 | netdev_features_t features) | |
16 | { | |
2e598af7 | 17 | int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); |
c50cd357 | 18 | struct sk_buff *segs = ERR_PTR(-EINVAL); |
7a7ffbab | 19 | u16 mac_offset = skb->mac_header; |
c50cd357 | 20 | __be16 protocol = skb->protocol; |
2e598af7 AD |
21 | u16 mac_len = skb->mac_len; |
22 | int gre_offset, outer_hlen; | |
880388aa | 23 | bool need_csum, gso_partial; |
c50cd357 | 24 | |
53e50398 TH |
25 | if (!skb->encapsulation) |
26 | goto out; | |
27 | ||
2e598af7 | 28 | if (unlikely(tnl_hlen < sizeof(struct gre_base_hdr))) |
c50cd357 DB |
29 | goto out; |
30 | ||
2e598af7 | 31 | if (unlikely(!pskb_may_pull(skb, tnl_hlen))) |
b884b1a4 NC |
32 | goto out; |
33 | ||
c50cd357 | 34 | /* setup inner skb. */ |
c50cd357 | 35 | skb->encapsulation = 0; |
5197f349 | 36 | SKB_GSO_CB(skb)->encap_level = 0; |
2e598af7 | 37 | __skb_pull(skb, tnl_hlen); |
c50cd357 DB |
38 | skb_reset_mac_header(skb); |
39 | skb_set_network_header(skb, skb_inner_network_offset(skb)); | |
40 | skb->mac_len = skb_inner_network_offset(skb); | |
38720352 | 41 | skb->protocol = skb->inner_protocol; |
c50cd357 | 42 | |
2e598af7 AD |
43 | need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM); |
44 | skb->encap_hdr_csum = need_csum; | |
45 | ||
bef3c6c9 AD |
46 | features &= skb->dev->hw_enc_features; |
47 | ||
c50cd357 | 48 | /* segment inner packet. */ |
bef3c6c9 | 49 | segs = skb_mac_gso_segment(skb, features); |
5a8dbf03 | 50 | if (IS_ERR_OR_NULL(segs)) { |
2e598af7 AD |
51 | skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset, |
52 | mac_len); | |
c50cd357 | 53 | goto out; |
7a7ffbab | 54 | } |
c50cd357 | 55 | |
07b26c94 SK |
56 | gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); |
57 | ||
2e598af7 AD |
58 | outer_hlen = skb_tnl_header_len(skb); |
59 | gre_offset = outer_hlen - tnl_hlen; | |
c50cd357 | 60 | skb = segs; |
c50cd357 | 61 | do { |
38720352 | 62 | struct gre_base_hdr *greh; |
802ab55a | 63 | __sum16 *pcsum; |
c50cd357 | 64 | |
22463876 AD |
65 | /* Set up inner headers if we are offloading inner checksum */ |
66 | if (skb->ip_summed == CHECKSUM_PARTIAL) { | |
67 | skb_reset_inner_headers(skb); | |
68 | skb->encapsulation = 1; | |
69 | } | |
cdbaa0bb | 70 | |
c50cd357 DB |
71 | skb->mac_len = mac_len; |
72 | skb->protocol = protocol; | |
2e598af7 AD |
73 | |
74 | __skb_push(skb, outer_hlen); | |
75 | skb_reset_mac_header(skb); | |
76 | skb_set_network_header(skb, mac_len); | |
77 | skb_set_transport_header(skb, gre_offset); | |
78 | ||
79 | if (!need_csum) | |
80 | continue; | |
81 | ||
82 | greh = (struct gre_base_hdr *)skb_transport_header(skb); | |
802ab55a AD |
83 | pcsum = (__sum16 *)(greh + 1); |
84 | ||
3d0241d5 | 85 | if (gso_partial && skb_is_gso(skb)) { |
802ab55a AD |
86 | unsigned int partial_adj; |
87 | ||
88 | /* Adjust checksum to account for the fact that | |
89 | * the partial checksum is based on actual size | |
90 | * whereas headers should be based on MSS size. | |
91 | */ | |
92 | partial_adj = skb->len + skb_headroom(skb) - | |
93 | SKB_GSO_CB(skb)->data_offset - | |
94 | skb_shinfo(skb)->gso_size; | |
95 | *pcsum = ~csum_fold((__force __wsum)htonl(partial_adj)); | |
96 | } else { | |
97 | *pcsum = 0; | |
98 | } | |
2e598af7 | 99 | |
802ab55a AD |
100 | *(pcsum + 1) = 0; |
101 | *pcsum = gso_make_checksum(skb, 0); | |
c50cd357 DB |
102 | } while ((skb = skb->next)); |
103 | out: | |
104 | return segs; | |
105 | } | |
106 | ||
d4546c25 DM |
107 | static struct sk_buff *gre_gro_receive(struct list_head *head, |
108 | struct sk_buff *skb) | |
bf5a755f | 109 | { |
d4546c25 | 110 | struct sk_buff *pp = NULL; |
bf5a755f JC |
111 | struct sk_buff *p; |
112 | const struct gre_base_hdr *greh; | |
113 | unsigned int hlen, grehlen; | |
114 | unsigned int off; | |
115 | int flush = 1; | |
116 | struct packet_offload *ptype; | |
117 | __be16 type; | |
118 | ||
fac8e0f5 JG |
119 | if (NAPI_GRO_CB(skb)->encap_mark) |
120 | goto out; | |
121 | ||
122 | NAPI_GRO_CB(skb)->encap_mark = 1; | |
123 | ||
bf5a755f JC |
124 | off = skb_gro_offset(skb); |
125 | hlen = off + sizeof(*greh); | |
126 | greh = skb_gro_header_fast(skb, off); | |
127 | if (skb_gro_header_hard(skb, hlen)) { | |
128 | greh = skb_gro_header_slow(skb, hlen, off); | |
129 | if (unlikely(!greh)) | |
130 | goto out; | |
131 | } | |
132 | ||
133 | /* Only support version 0 and K (key), C (csum) flags. Note that | |
134 | * although the support for the S (seq#) flag can be added easily | |
135 | * for GRO, this is problematic for GSO hence can not be enabled | |
136 | * here because a GRO pkt may end up in the forwarding path, thus | |
137 | * requiring GSO support to break it up correctly. | |
138 | */ | |
139 | if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0) | |
140 | goto out; | |
141 | ||
a0ca153f AD |
142 | /* We can only support GRE_CSUM if we can track the location of |
143 | * the GRE header. In the case of FOU/GUE we cannot because the | |
144 | * outer UDP header displaces the GRE header leaving us in a state | |
145 | * of limbo. | |
146 | */ | |
147 | if ((greh->flags & GRE_CSUM) && NAPI_GRO_CB(skb)->is_fou) | |
148 | goto out; | |
149 | ||
bf5a755f JC |
150 | type = greh->protocol; |
151 | ||
152 | rcu_read_lock(); | |
153 | ptype = gro_find_receive_by_type(type); | |
51456b29 | 154 | if (!ptype) |
bf5a755f JC |
155 | goto out_unlock; |
156 | ||
157 | grehlen = GRE_HEADER_SECTION; | |
158 | ||
159 | if (greh->flags & GRE_KEY) | |
160 | grehlen += GRE_HEADER_SECTION; | |
161 | ||
162 | if (greh->flags & GRE_CSUM) | |
163 | grehlen += GRE_HEADER_SECTION; | |
164 | ||
165 | hlen = off + grehlen; | |
166 | if (skb_gro_header_hard(skb, hlen)) { | |
167 | greh = skb_gro_header_slow(skb, hlen, off); | |
168 | if (unlikely(!greh)) | |
169 | goto out_unlock; | |
170 | } | |
758f75d1 TH |
171 | |
172 | /* Don't bother verifying checksum if we're going to flush anyway. */ | |
884d338c TH |
173 | if ((greh->flags & GRE_CSUM) && !NAPI_GRO_CB(skb)->flush) { |
174 | if (skb_gro_checksum_simple_validate(skb)) | |
bf5a755f | 175 | goto out_unlock; |
758f75d1 | 176 | |
884d338c TH |
177 | skb_gro_checksum_try_convert(skb, IPPROTO_GRE, 0, |
178 | null_compute_pseudo); | |
179 | } | |
180 | ||
d4546c25 | 181 | list_for_each_entry(p, head, list) { |
bf5a755f JC |
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 | ||
fcd91dd4 | 216 | pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb); |
c194cf93 | 217 | flush = 0; |
bf5a755f JC |
218 | |
219 | out_unlock: | |
220 | rcu_read_unlock(); | |
221 | out: | |
603d4cf8 | 222 | skb_gro_flush_final(skb, pp, flush); |
bf5a755f JC |
223 | |
224 | return pp; | |
225 | } | |
226 | ||
d10dbad2 | 227 | static int gre_gro_complete(struct sk_buff *skb, int nhoff) |
bf5a755f JC |
228 | { |
229 | struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff); | |
230 | struct packet_offload *ptype; | |
231 | unsigned int grehlen = sizeof(*greh); | |
232 | int err = -ENOENT; | |
233 | __be16 type; | |
234 | ||
c3caf119 JC |
235 | skb->encapsulation = 1; |
236 | skb_shinfo(skb)->gso_type = SKB_GSO_GRE; | |
237 | ||
bf5a755f JC |
238 | type = greh->protocol; |
239 | if (greh->flags & GRE_KEY) | |
240 | grehlen += GRE_HEADER_SECTION; | |
241 | ||
242 | if (greh->flags & GRE_CSUM) | |
243 | grehlen += GRE_HEADER_SECTION; | |
244 | ||
245 | rcu_read_lock(); | |
246 | ptype = gro_find_complete_by_type(type); | |
00db4124 | 247 | if (ptype) |
bf5a755f JC |
248 | err = ptype->callbacks.gro_complete(skb, nhoff + grehlen); |
249 | ||
250 | rcu_read_unlock(); | |
6fb2a756 TH |
251 | |
252 | skb_set_inner_mac_header(skb, nhoff + grehlen); | |
253 | ||
bf5a755f JC |
254 | return err; |
255 | } | |
256 | ||
c50cd357 DB |
257 | static const struct net_offload gre_offload = { |
258 | .callbacks = { | |
c50cd357 | 259 | .gso_segment = gre_gso_segment, |
bf5a755f JC |
260 | .gro_receive = gre_gro_receive, |
261 | .gro_complete = gre_gro_complete, | |
c50cd357 DB |
262 | }, |
263 | }; | |
264 | ||
438e38fa | 265 | static int __init gre_offload_init(void) |
c50cd357 | 266 | { |
e0c20967 AD |
267 | int err; |
268 | ||
269 | err = inet_add_offload(&gre_offload, IPPROTO_GRE); | |
270 | #if IS_ENABLED(CONFIG_IPV6) | |
271 | if (err) | |
272 | return err; | |
273 | ||
274 | err = inet6_add_offload(&gre_offload, IPPROTO_GRE); | |
275 | if (err) | |
276 | inet_del_offload(&gre_offload, IPPROTO_GRE); | |
277 | #endif | |
278 | ||
279 | return err; | |
c50cd357 | 280 | } |
cf172283 | 281 | device_initcall(gre_offload_init); |