2 * IPV4 GSO/GRO offload support
3 * Linux INET implementation
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.
13 #include <linux/skbuff.h>
15 #include <net/protocol.h>
17 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
18 netdev_features_t features,
19 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
20 netdev_features_t features),
21 __be16 new_protocol, bool is_ipv6)
23 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
24 bool remcsum, need_csum, offload_csum, ufo, gso_partial;
25 struct sk_buff *segs = ERR_PTR(-EINVAL);
26 struct udphdr *uh = udp_hdr(skb);
27 u16 mac_offset = skb->mac_header;
28 __be16 protocol = skb->protocol;
29 u16 mac_len = skb->mac_len;
30 int udp_offset, outer_hlen;
34 if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
37 /* Adjust partial header checksum to negate old length.
38 * We cannot rely on the value contained in uh->len as it is
39 * possible that the actual value exceeds the boundaries of the
40 * 16 bit length field due to the header being added outside of an
41 * IP or IPv6 frame that was already limited to 64K - 1.
43 if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
44 partial = (__force __wsum)uh->len;
46 partial = (__force __wsum)htonl(skb->len);
47 partial = csum_sub(csum_unfold(uh->check), partial);
49 /* setup inner skb. */
50 skb->encapsulation = 0;
51 SKB_GSO_CB(skb)->encap_level = 0;
52 __skb_pull(skb, tnl_hlen);
53 skb_reset_mac_header(skb);
54 skb_set_network_header(skb, skb_inner_network_offset(skb));
55 skb->mac_len = skb_inner_network_offset(skb);
56 skb->protocol = new_protocol;
58 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
59 skb->encap_hdr_csum = need_csum;
61 remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
62 skb->remcsum_offload = remcsum;
64 ufo = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
66 need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
67 /* Try to offload checksum if possible */
68 offload_csum = !!(need_csum &&
71 (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
72 (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
74 features &= skb->dev->hw_enc_features;
76 /* The only checksum offload we care about from here on out is the
77 * outer one so strip the existing checksum feature flags and
78 * instead set the flag based on our outer checksum offload value.
81 features &= ~NETIF_F_CSUM_MASK;
82 if (!need_csum || offload_csum)
83 features |= NETIF_F_HW_CSUM;
86 /* segment inner packet. */
87 segs = gso_inner_segment(skb, features);
88 if (IS_ERR_OR_NULL(segs)) {
89 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
94 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
96 outer_hlen = skb_tnl_header_len(skb);
97 udp_offset = outer_hlen - tnl_hlen;
103 skb->ip_summed = CHECKSUM_NONE;
105 /* Set up inner headers if we are offloading inner checksum */
106 if (skb->ip_summed == CHECKSUM_PARTIAL) {
107 skb_reset_inner_headers(skb);
108 skb->encapsulation = 1;
111 skb->mac_len = mac_len;
112 skb->protocol = protocol;
114 __skb_push(skb, outer_hlen);
115 skb_reset_mac_header(skb);
116 skb_set_network_header(skb, mac_len);
117 skb_set_transport_header(skb, udp_offset);
118 len = skb->len - udp_offset;
121 /* If we are only performing partial GSO the inner header
122 * will be using a length value equal to only one MSS sized
123 * segment instead of the entire frame.
126 uh->len = htons(skb_shinfo(skb)->gso_size +
127 SKB_GSO_CB(skb)->data_offset +
128 skb->head - (unsigned char *)uh);
130 uh->len = htons(len);
136 uh->check = ~csum_fold(csum_add(partial,
137 (__force __wsum)htonl(len)));
139 if (skb->encapsulation || !offload_csum) {
140 uh->check = gso_make_checksum(skb, ~uh->check);
142 uh->check = CSUM_MANGLED_0;
144 skb->ip_summed = CHECKSUM_PARTIAL;
145 skb->csum_start = skb_transport_header(skb) - skb->head;
146 skb->csum_offset = offsetof(struct udphdr, check);
148 } while ((skb = skb->next));
153 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
154 netdev_features_t features,
157 __be16 protocol = skb->protocol;
158 const struct net_offload **offloads;
159 const struct net_offload *ops;
160 struct sk_buff *segs = ERR_PTR(-EINVAL);
161 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
162 netdev_features_t features);
166 switch (skb->inner_protocol_type) {
167 case ENCAP_TYPE_ETHER:
168 protocol = skb->inner_protocol;
169 gso_inner_segment = skb_mac_gso_segment;
171 case ENCAP_TYPE_IPPROTO:
172 offloads = is_ipv6 ? inet6_offloads : inet_offloads;
173 ops = rcu_dereference(offloads[skb->inner_ipproto]);
174 if (!ops || !ops->callbacks.gso_segment)
176 gso_inner_segment = ops->callbacks.gso_segment;
182 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
190 EXPORT_SYMBOL(skb_udp_tunnel_segment);
192 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
193 netdev_features_t features)
195 struct sk_buff *segs = ERR_PTR(-EINVAL);
201 if (skb->encapsulation &&
202 (skb_shinfo(skb)->gso_type &
203 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
204 segs = skb_udp_tunnel_segment(skb, features, false);
208 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
211 mss = skb_shinfo(skb)->gso_size;
212 if (unlikely(skb->len <= mss))
215 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
216 /* Packet is from an untrusted source, reset gso_segs. */
218 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
224 /* Do software UFO. Complete and fill in the UDP checksum as
225 * HW cannot do checksum of UDP packets sent as multiple
233 csum = skb_checksum(skb, 0, skb->len, 0);
234 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
236 uh->check = CSUM_MANGLED_0;
238 skb->ip_summed = CHECKSUM_NONE;
240 /* If there is no outer header we can fake a checksum offload
241 * due to the fact that we have already done the checksum in
242 * software prior to segmenting the frame.
244 if (!skb->encap_hdr_csum)
245 features |= NETIF_F_HW_CSUM;
247 /* Fragment the skb. IP headers of the fragments are updated in
250 segs = skb_segment(skb, features);
255 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
256 struct udphdr *uh, udp_lookup_t lookup)
258 struct sk_buff *p, **pp = NULL;
260 unsigned int off = skb_gro_offset(skb);
264 if (NAPI_GRO_CB(skb)->encap_mark ||
265 (skb->ip_summed != CHECKSUM_PARTIAL &&
266 NAPI_GRO_CB(skb)->csum_cnt == 0 &&
267 !NAPI_GRO_CB(skb)->csum_valid))
270 /* mark that this skb passed once through the tunnel gro layer */
271 NAPI_GRO_CB(skb)->encap_mark = 1;
274 sk = (*lookup)(skb, uh->source, uh->dest);
276 if (sk && udp_sk(sk)->gro_receive)
283 for (p = *head; p; p = p->next) {
284 if (!NAPI_GRO_CB(p)->same_flow)
287 uh2 = (struct udphdr *)(p->data + off);
289 /* Match ports and either checksums are either both zero
292 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
293 (!uh->check ^ !uh2->check)) {
294 NAPI_GRO_CB(p)->same_flow = 0;
299 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
300 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
301 pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
306 NAPI_GRO_CB(skb)->flush |= flush;
309 EXPORT_SYMBOL(udp_gro_receive);
311 static struct sk_buff **udp4_gro_receive(struct sk_buff **head,
314 struct udphdr *uh = udp_gro_udphdr(skb);
319 /* Don't bother verifying checksum if we're going to flush anyway. */
320 if (NAPI_GRO_CB(skb)->flush)
323 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
324 inet_gro_compute_pseudo))
327 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
328 inet_gro_compute_pseudo);
330 NAPI_GRO_CB(skb)->is_ipv6 = 0;
331 return udp_gro_receive(head, skb, uh, udp4_lib_lookup_skb);
334 NAPI_GRO_CB(skb)->flush = 1;
338 int udp_gro_complete(struct sk_buff *skb, int nhoff,
341 __be16 newlen = htons(skb->len - nhoff);
342 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
348 /* Set encapsulation before calling into inner gro_complete() functions
349 * to make them set up the inner offsets.
351 skb->encapsulation = 1;
354 sk = (*lookup)(skb, uh->source, uh->dest);
355 if (sk && udp_sk(sk)->gro_complete)
356 err = udp_sk(sk)->gro_complete(sk, skb,
357 nhoff + sizeof(struct udphdr));
360 if (skb->remcsum_offload)
361 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
365 EXPORT_SYMBOL(udp_gro_complete);
367 static int udp4_gro_complete(struct sk_buff *skb, int nhoff)
369 const struct iphdr *iph = ip_hdr(skb);
370 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
373 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
374 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
377 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
380 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
383 static const struct net_offload udpv4_offload = {
385 .gso_segment = udp4_ufo_fragment,
386 .gro_receive = udp4_gro_receive,
387 .gro_complete = udp4_gro_complete,
391 int __init udpv4_offload_init(void)
393 return inet_add_offload(&udpv4_offload, IPPROTO_UDP);