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da5bab07 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 | * UDPv4 GSO support | |
11 | */ | |
12 | ||
13 | #include <linux/skbuff.h> | |
14 | #include <net/udp.h> | |
15 | #include <net/protocol.h> | |
16 | ||
b582ef09 | 17 | static DEFINE_SPINLOCK(udp_offload_lock); |
a1d0cd8e | 18 | static struct udp_offload_priv __rcu *udp_offload_base __read_mostly; |
b582ef09 OG |
19 | |
20 | struct udp_offload_priv { | |
21 | struct udp_offload *offload; | |
22 | struct rcu_head rcu; | |
23 | struct udp_offload_priv __rcu *next; | |
24 | }; | |
25 | ||
da5bab07 DB |
26 | static int udp4_ufo_send_check(struct sk_buff *skb) |
27 | { | |
28 | if (!pskb_may_pull(skb, sizeof(struct udphdr))) | |
29 | return -EINVAL; | |
30 | ||
31 | if (likely(!skb->encapsulation)) { | |
32 | const struct iphdr *iph; | |
33 | struct udphdr *uh; | |
34 | ||
35 | iph = ip_hdr(skb); | |
36 | uh = udp_hdr(skb); | |
37 | ||
38 | uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len, | |
39 | IPPROTO_UDP, 0); | |
40 | skb->csum_start = skb_transport_header(skb) - skb->head; | |
41 | skb->csum_offset = offsetof(struct udphdr, check); | |
42 | skb->ip_summed = CHECKSUM_PARTIAL; | |
43 | } | |
44 | ||
45 | return 0; | |
46 | } | |
47 | ||
48 | static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, | |
49 | netdev_features_t features) | |
50 | { | |
51 | struct sk_buff *segs = ERR_PTR(-EINVAL); | |
52 | unsigned int mss; | |
7a7ffbab WCC |
53 | int offset; |
54 | __wsum csum; | |
55 | ||
56 | if (skb->encapsulation && | |
57 | skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) { | |
58 | segs = skb_udp_tunnel_segment(skb, features); | |
59 | goto out; | |
60 | } | |
da5bab07 DB |
61 | |
62 | mss = skb_shinfo(skb)->gso_size; | |
63 | if (unlikely(skb->len <= mss)) | |
64 | goto out; | |
65 | ||
66 | if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { | |
67 | /* Packet is from an untrusted source, reset gso_segs. */ | |
68 | int type = skb_shinfo(skb)->gso_type; | |
69 | ||
70 | if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY | | |
71 | SKB_GSO_UDP_TUNNEL | | |
cb32f511 | 72 | SKB_GSO_IPIP | |
da5bab07 DB |
73 | SKB_GSO_GRE | SKB_GSO_MPLS) || |
74 | !(type & (SKB_GSO_UDP)))) | |
75 | goto out; | |
76 | ||
77 | skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); | |
78 | ||
79 | segs = NULL; | |
80 | goto out; | |
81 | } | |
82 | ||
7a7ffbab WCC |
83 | /* Do software UFO. Complete and fill in the UDP checksum as |
84 | * HW cannot do checksum of UDP packets sent as multiple | |
85 | * IP fragments. | |
86 | */ | |
87 | offset = skb_checksum_start_offset(skb); | |
88 | csum = skb_checksum(skb, offset, skb->len - offset, 0); | |
89 | offset += skb->csum_offset; | |
90 | *(__sum16 *)(skb->data + offset) = csum_fold(csum); | |
91 | skb->ip_summed = CHECKSUM_NONE; | |
92 | ||
da5bab07 DB |
93 | /* Fragment the skb. IP headers of the fragments are updated in |
94 | * inet_gso_segment() | |
95 | */ | |
7a7ffbab | 96 | segs = skb_segment(skb, features); |
da5bab07 DB |
97 | out: |
98 | return segs; | |
99 | } | |
100 | ||
b582ef09 OG |
101 | int udp_add_offload(struct udp_offload *uo) |
102 | { | |
a1d0cd8e | 103 | struct udp_offload_priv __rcu **head = &udp_offload_base; |
b5aaab12 | 104 | struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC); |
b582ef09 OG |
105 | |
106 | if (!new_offload) | |
107 | return -ENOMEM; | |
108 | ||
109 | new_offload->offload = uo; | |
110 | ||
111 | spin_lock(&udp_offload_lock); | |
112 | rcu_assign_pointer(new_offload->next, rcu_dereference(*head)); | |
a1d0cd8e | 113 | rcu_assign_pointer(*head, new_offload); |
b582ef09 OG |
114 | spin_unlock(&udp_offload_lock); |
115 | ||
116 | return 0; | |
117 | } | |
118 | EXPORT_SYMBOL(udp_add_offload); | |
119 | ||
120 | static void udp_offload_free_routine(struct rcu_head *head) | |
121 | { | |
122 | struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu); | |
123 | kfree(ou_priv); | |
124 | } | |
125 | ||
126 | void udp_del_offload(struct udp_offload *uo) | |
127 | { | |
128 | struct udp_offload_priv __rcu **head = &udp_offload_base; | |
129 | struct udp_offload_priv *uo_priv; | |
130 | ||
131 | spin_lock(&udp_offload_lock); | |
132 | ||
133 | uo_priv = rcu_dereference(*head); | |
134 | for (; uo_priv != NULL; | |
135 | uo_priv = rcu_dereference(*head)) { | |
136 | ||
137 | if (uo_priv->offload == uo) { | |
138 | rcu_assign_pointer(*head, rcu_dereference(uo_priv->next)); | |
139 | goto unlock; | |
140 | } | |
141 | head = &uo_priv->next; | |
142 | } | |
a1d0cd8e | 143 | pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port)); |
b582ef09 OG |
144 | unlock: |
145 | spin_unlock(&udp_offload_lock); | |
146 | if (uo_priv != NULL) | |
147 | call_rcu(&uo_priv->rcu, udp_offload_free_routine); | |
148 | } | |
149 | EXPORT_SYMBOL(udp_del_offload); | |
150 | ||
151 | static struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb) | |
152 | { | |
153 | struct udp_offload_priv *uo_priv; | |
154 | struct sk_buff *p, **pp = NULL; | |
155 | struct udphdr *uh, *uh2; | |
156 | unsigned int hlen, off; | |
157 | int flush = 1; | |
158 | ||
159 | if (NAPI_GRO_CB(skb)->udp_mark || | |
160 | (!skb->encapsulation && skb->ip_summed != CHECKSUM_COMPLETE)) | |
161 | goto out; | |
162 | ||
163 | /* mark that this skb passed once through the udp gro layer */ | |
164 | NAPI_GRO_CB(skb)->udp_mark = 1; | |
165 | ||
166 | off = skb_gro_offset(skb); | |
167 | hlen = off + sizeof(*uh); | |
168 | uh = skb_gro_header_fast(skb, off); | |
169 | if (skb_gro_header_hard(skb, hlen)) { | |
170 | uh = skb_gro_header_slow(skb, hlen, off); | |
171 | if (unlikely(!uh)) | |
172 | goto out; | |
173 | } | |
174 | ||
175 | rcu_read_lock(); | |
176 | uo_priv = rcu_dereference(udp_offload_base); | |
177 | for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { | |
178 | if (uo_priv->offload->port == uh->dest && | |
179 | uo_priv->offload->callbacks.gro_receive) | |
180 | goto unflush; | |
181 | } | |
182 | goto out_unlock; | |
183 | ||
184 | unflush: | |
185 | flush = 0; | |
186 | ||
187 | for (p = *head; p; p = p->next) { | |
188 | if (!NAPI_GRO_CB(p)->same_flow) | |
189 | continue; | |
190 | ||
191 | uh2 = (struct udphdr *)(p->data + off); | |
192 | if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) { | |
193 | NAPI_GRO_CB(p)->same_flow = 0; | |
194 | continue; | |
195 | } | |
196 | } | |
197 | ||
198 | skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ | |
199 | pp = uo_priv->offload->callbacks.gro_receive(head, skb); | |
200 | ||
201 | out_unlock: | |
202 | rcu_read_unlock(); | |
203 | out: | |
204 | NAPI_GRO_CB(skb)->flush |= flush; | |
205 | return pp; | |
206 | } | |
207 | ||
208 | static int udp_gro_complete(struct sk_buff *skb, int nhoff) | |
209 | { | |
210 | struct udp_offload_priv *uo_priv; | |
211 | __be16 newlen = htons(skb->len - nhoff); | |
212 | struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); | |
213 | int err = -ENOSYS; | |
214 | ||
215 | uh->len = newlen; | |
216 | ||
217 | rcu_read_lock(); | |
218 | ||
219 | uo_priv = rcu_dereference(udp_offload_base); | |
220 | for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { | |
221 | if (uo_priv->offload->port == uh->dest && | |
222 | uo_priv->offload->callbacks.gro_complete) | |
223 | break; | |
224 | } | |
225 | ||
226 | if (uo_priv != NULL) | |
227 | err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr)); | |
228 | ||
229 | rcu_read_unlock(); | |
230 | return err; | |
231 | } | |
232 | ||
da5bab07 DB |
233 | static const struct net_offload udpv4_offload = { |
234 | .callbacks = { | |
235 | .gso_send_check = udp4_ufo_send_check, | |
236 | .gso_segment = udp4_ufo_fragment, | |
b582ef09 OG |
237 | .gro_receive = udp_gro_receive, |
238 | .gro_complete = udp_gro_complete, | |
da5bab07 DB |
239 | }, |
240 | }; | |
241 | ||
242 | int __init udpv4_offload_init(void) | |
243 | { | |
244 | return inet_add_offload(&udpv4_offload, IPPROTO_UDP); | |
245 | } |