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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 | 19 | |
a664a4f7 SP |
20 | #define udp_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&udp_offload_lock)) |
21 | ||
b582ef09 OG |
22 | struct udp_offload_priv { |
23 | struct udp_offload *offload; | |
24 | struct rcu_head rcu; | |
25 | struct udp_offload_priv __rcu *next; | |
26 | }; | |
27 | ||
da5bab07 DB |
28 | static int udp4_ufo_send_check(struct sk_buff *skb) |
29 | { | |
30 | if (!pskb_may_pull(skb, sizeof(struct udphdr))) | |
31 | return -EINVAL; | |
32 | ||
33 | if (likely(!skb->encapsulation)) { | |
34 | const struct iphdr *iph; | |
35 | struct udphdr *uh; | |
36 | ||
37 | iph = ip_hdr(skb); | |
38 | uh = udp_hdr(skb); | |
39 | ||
40 | uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len, | |
41 | IPPROTO_UDP, 0); | |
42 | skb->csum_start = skb_transport_header(skb) - skb->head; | |
43 | skb->csum_offset = offsetof(struct udphdr, check); | |
44 | skb->ip_summed = CHECKSUM_PARTIAL; | |
45 | } | |
46 | ||
47 | return 0; | |
48 | } | |
49 | ||
50 | static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, | |
51 | netdev_features_t features) | |
52 | { | |
53 | struct sk_buff *segs = ERR_PTR(-EINVAL); | |
54 | unsigned int mss; | |
7a7ffbab WCC |
55 | int offset; |
56 | __wsum csum; | |
57 | ||
58 | if (skb->encapsulation && | |
59 | skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) { | |
60 | segs = skb_udp_tunnel_segment(skb, features); | |
61 | goto out; | |
62 | } | |
da5bab07 DB |
63 | |
64 | mss = skb_shinfo(skb)->gso_size; | |
65 | if (unlikely(skb->len <= mss)) | |
66 | goto out; | |
67 | ||
68 | if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { | |
69 | /* Packet is from an untrusted source, reset gso_segs. */ | |
70 | int type = skb_shinfo(skb)->gso_type; | |
71 | ||
72 | if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY | | |
73 | SKB_GSO_UDP_TUNNEL | | |
cb32f511 | 74 | SKB_GSO_IPIP | |
da5bab07 DB |
75 | SKB_GSO_GRE | SKB_GSO_MPLS) || |
76 | !(type & (SKB_GSO_UDP)))) | |
77 | goto out; | |
78 | ||
79 | skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); | |
80 | ||
81 | segs = NULL; | |
82 | goto out; | |
83 | } | |
84 | ||
7a7ffbab WCC |
85 | /* Do software UFO. Complete and fill in the UDP checksum as |
86 | * HW cannot do checksum of UDP packets sent as multiple | |
87 | * IP fragments. | |
88 | */ | |
89 | offset = skb_checksum_start_offset(skb); | |
90 | csum = skb_checksum(skb, offset, skb->len - offset, 0); | |
91 | offset += skb->csum_offset; | |
92 | *(__sum16 *)(skb->data + offset) = csum_fold(csum); | |
93 | skb->ip_summed = CHECKSUM_NONE; | |
94 | ||
da5bab07 DB |
95 | /* Fragment the skb. IP headers of the fragments are updated in |
96 | * inet_gso_segment() | |
97 | */ | |
7a7ffbab | 98 | segs = skb_segment(skb, features); |
da5bab07 DB |
99 | out: |
100 | return segs; | |
101 | } | |
102 | ||
b582ef09 OG |
103 | int udp_add_offload(struct udp_offload *uo) |
104 | { | |
b5aaab12 | 105 | struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC); |
b582ef09 OG |
106 | |
107 | if (!new_offload) | |
108 | return -ENOMEM; | |
109 | ||
110 | new_offload->offload = uo; | |
111 | ||
112 | spin_lock(&udp_offload_lock); | |
a664a4f7 SP |
113 | new_offload->next = udp_offload_base; |
114 | rcu_assign_pointer(udp_offload_base, new_offload); | |
b582ef09 OG |
115 | spin_unlock(&udp_offload_lock); |
116 | ||
117 | return 0; | |
118 | } | |
119 | EXPORT_SYMBOL(udp_add_offload); | |
120 | ||
121 | static void udp_offload_free_routine(struct rcu_head *head) | |
122 | { | |
123 | struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu); | |
124 | kfree(ou_priv); | |
125 | } | |
126 | ||
127 | void udp_del_offload(struct udp_offload *uo) | |
128 | { | |
129 | struct udp_offload_priv __rcu **head = &udp_offload_base; | |
130 | struct udp_offload_priv *uo_priv; | |
131 | ||
132 | spin_lock(&udp_offload_lock); | |
133 | ||
a664a4f7 | 134 | uo_priv = udp_deref_protected(*head); |
b582ef09 | 135 | for (; uo_priv != NULL; |
a664a4f7 | 136 | uo_priv = udp_deref_protected(*head)) { |
b582ef09 | 137 | if (uo_priv->offload == uo) { |
a664a4f7 SP |
138 | rcu_assign_pointer(*head, |
139 | udp_deref_protected(uo_priv->next)); | |
b582ef09 OG |
140 | goto unlock; |
141 | } | |
142 | head = &uo_priv->next; | |
143 | } | |
a1d0cd8e | 144 | pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port)); |
b582ef09 OG |
145 | unlock: |
146 | spin_unlock(&udp_offload_lock); | |
147 | if (uo_priv != NULL) | |
148 | call_rcu(&uo_priv->rcu, udp_offload_free_routine); | |
149 | } | |
150 | EXPORT_SYMBOL(udp_del_offload); | |
151 | ||
152 | static struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb) | |
153 | { | |
154 | struct udp_offload_priv *uo_priv; | |
155 | struct sk_buff *p, **pp = NULL; | |
156 | struct udphdr *uh, *uh2; | |
157 | unsigned int hlen, off; | |
158 | int flush = 1; | |
159 | ||
160 | if (NAPI_GRO_CB(skb)->udp_mark || | |
161 | (!skb->encapsulation && skb->ip_summed != CHECKSUM_COMPLETE)) | |
162 | goto out; | |
163 | ||
164 | /* mark that this skb passed once through the udp gro layer */ | |
165 | NAPI_GRO_CB(skb)->udp_mark = 1; | |
166 | ||
167 | off = skb_gro_offset(skb); | |
168 | hlen = off + sizeof(*uh); | |
169 | uh = skb_gro_header_fast(skb, off); | |
170 | if (skb_gro_header_hard(skb, hlen)) { | |
171 | uh = skb_gro_header_slow(skb, hlen, off); | |
172 | if (unlikely(!uh)) | |
173 | goto out; | |
174 | } | |
175 | ||
176 | rcu_read_lock(); | |
177 | uo_priv = rcu_dereference(udp_offload_base); | |
178 | for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { | |
179 | if (uo_priv->offload->port == uh->dest && | |
180 | uo_priv->offload->callbacks.gro_receive) | |
181 | goto unflush; | |
182 | } | |
183 | goto out_unlock; | |
184 | ||
185 | unflush: | |
186 | flush = 0; | |
187 | ||
188 | for (p = *head; p; p = p->next) { | |
189 | if (!NAPI_GRO_CB(p)->same_flow) | |
190 | continue; | |
191 | ||
192 | uh2 = (struct udphdr *)(p->data + off); | |
193 | if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) { | |
194 | NAPI_GRO_CB(p)->same_flow = 0; | |
195 | continue; | |
196 | } | |
197 | } | |
198 | ||
199 | skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ | |
200 | pp = uo_priv->offload->callbacks.gro_receive(head, skb); | |
201 | ||
202 | out_unlock: | |
203 | rcu_read_unlock(); | |
204 | out: | |
205 | NAPI_GRO_CB(skb)->flush |= flush; | |
206 | return pp; | |
207 | } | |
208 | ||
209 | static int udp_gro_complete(struct sk_buff *skb, int nhoff) | |
210 | { | |
211 | struct udp_offload_priv *uo_priv; | |
212 | __be16 newlen = htons(skb->len - nhoff); | |
213 | struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); | |
214 | int err = -ENOSYS; | |
215 | ||
216 | uh->len = newlen; | |
217 | ||
218 | rcu_read_lock(); | |
219 | ||
220 | uo_priv = rcu_dereference(udp_offload_base); | |
221 | for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { | |
222 | if (uo_priv->offload->port == uh->dest && | |
223 | uo_priv->offload->callbacks.gro_complete) | |
224 | break; | |
225 | } | |
226 | ||
227 | if (uo_priv != NULL) | |
228 | err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr)); | |
229 | ||
230 | rcu_read_unlock(); | |
231 | return err; | |
232 | } | |
233 | ||
da5bab07 DB |
234 | static const struct net_offload udpv4_offload = { |
235 | .callbacks = { | |
236 | .gso_send_check = udp4_ufo_send_check, | |
237 | .gso_segment = udp4_ufo_fragment, | |
b582ef09 OG |
238 | .gro_receive = udp_gro_receive, |
239 | .gro_complete = udp_gro_complete, | |
da5bab07 DB |
240 | }, |
241 | }; | |
242 | ||
243 | int __init udpv4_offload_init(void) | |
244 | { | |
245 | return inet_add_offload(&udpv4_offload, IPPROTO_UDP); | |
246 | } |