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 17 static DEFINE_SPINLOCK(udp_offload_lock); 18 static struct udp_offload_priv __rcu *udp_offload_base __read_mostly; 19 20 #define udp_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&udp_offload_lock)) 21 22 struct udp_offload_priv { 23 struct udp_offload *offload; 24 possible_net_t net; 25 struct rcu_head rcu; 26 struct udp_offload_priv __rcu *next; 27 }; 28 29 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, 30 netdev_features_t features, 31 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, 32 netdev_features_t features), 33 __be16 new_protocol, bool is_ipv6) 34 { 35 struct sk_buff *segs = ERR_PTR(-EINVAL); 36 u16 mac_offset = skb->mac_header; 37 int mac_len = skb->mac_len; 38 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); 39 __be16 protocol = skb->protocol; 40 int udp_offset, outer_hlen; 41 unsigned int oldlen; 42 bool need_csum = !!(skb_shinfo(skb)->gso_type & 43 SKB_GSO_UDP_TUNNEL_CSUM); 44 bool remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM); 45 bool offload_csum = false, dont_encap = (need_csum || remcsum); 46 47 oldlen = (u16)~skb->len; 48 49 if (unlikely(!pskb_may_pull(skb, tnl_hlen))) 50 goto out; 51 52 skb->encapsulation = 0; 53 __skb_pull(skb, tnl_hlen); 54 skb_reset_mac_header(skb); 55 skb_set_network_header(skb, skb_inner_network_offset(skb)); 56 skb->mac_len = skb_inner_network_offset(skb); 57 skb->protocol = new_protocol; 58 skb->encap_hdr_csum = need_csum; 59 skb->remcsum_offload = remcsum; 60 61 /* Try to offload checksum if possible */ 62 offload_csum = !!(need_csum && 63 ((skb->dev->features & NETIF_F_HW_CSUM) || 64 (skb->dev->features & (is_ipv6 ? 65 NETIF_F_IPV6_CSUM : NETIF_F_IP_CSUM)))); 66 67 features &= skb->dev->hw_enc_features; 68 69 /* segment inner packet. */ 70 segs = gso_inner_segment(skb, features); 71 if (IS_ERR_OR_NULL(segs)) { 72 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset, 73 mac_len); 74 goto out; 75 } 76 77 outer_hlen = skb_tnl_header_len(skb); 78 udp_offset = outer_hlen - tnl_hlen; 79 skb = segs; 80 do { 81 struct udphdr *uh; 82 int len; 83 __be32 delta; 84 85 if (dont_encap) { 86 skb->encapsulation = 0; 87 skb->ip_summed = CHECKSUM_NONE; 88 } else { 89 /* Only set up inner headers if we might be offloading 90 * inner checksum. 91 */ 92 skb_reset_inner_headers(skb); 93 skb->encapsulation = 1; 94 } 95 96 skb->mac_len = mac_len; 97 skb->protocol = protocol; 98 99 skb_push(skb, outer_hlen); 100 skb_reset_mac_header(skb); 101 skb_set_network_header(skb, mac_len); 102 skb_set_transport_header(skb, udp_offset); 103 len = skb->len - udp_offset; 104 uh = udp_hdr(skb); 105 uh->len = htons(len); 106 107 if (!need_csum) 108 continue; 109 110 delta = htonl(oldlen + len); 111 112 uh->check = ~csum_fold((__force __wsum) 113 ((__force u32)uh->check + 114 (__force u32)delta)); 115 if (offload_csum) { 116 skb->ip_summed = CHECKSUM_PARTIAL; 117 skb->csum_start = skb_transport_header(skb) - skb->head; 118 skb->csum_offset = offsetof(struct udphdr, check); 119 } else if (remcsum) { 120 /* Need to calculate checksum from scratch, 121 * inner checksums are never when doing 122 * remote_checksum_offload. 123 */ 124 125 skb->csum = skb_checksum(skb, udp_offset, 126 skb->len - udp_offset, 127 0); 128 uh->check = csum_fold(skb->csum); 129 if (uh->check == 0) 130 uh->check = CSUM_MANGLED_0; 131 } else { 132 uh->check = gso_make_checksum(skb, ~uh->check); 133 134 if (uh->check == 0) 135 uh->check = CSUM_MANGLED_0; 136 } 137 } while ((skb = skb->next)); 138 out: 139 return segs; 140 } 141 142 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 143 netdev_features_t features, 144 bool is_ipv6) 145 { 146 __be16 protocol = skb->protocol; 147 const struct net_offload **offloads; 148 const struct net_offload *ops; 149 struct sk_buff *segs = ERR_PTR(-EINVAL); 150 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, 151 netdev_features_t features); 152 153 rcu_read_lock(); 154 155 switch (skb->inner_protocol_type) { 156 case ENCAP_TYPE_ETHER: 157 protocol = skb->inner_protocol; 158 gso_inner_segment = skb_mac_gso_segment; 159 break; 160 case ENCAP_TYPE_IPPROTO: 161 offloads = is_ipv6 ? inet6_offloads : inet_offloads; 162 ops = rcu_dereference(offloads[skb->inner_ipproto]); 163 if (!ops || !ops->callbacks.gso_segment) 164 goto out_unlock; 165 gso_inner_segment = ops->callbacks.gso_segment; 166 break; 167 default: 168 goto out_unlock; 169 } 170 171 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment, 172 protocol, is_ipv6); 173 174 out_unlock: 175 rcu_read_unlock(); 176 177 return segs; 178 } 179 180 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, 181 netdev_features_t features) 182 { 183 struct sk_buff *segs = ERR_PTR(-EINVAL); 184 unsigned int mss; 185 __wsum csum; 186 struct udphdr *uh; 187 struct iphdr *iph; 188 189 if (skb->encapsulation && 190 (skb_shinfo(skb)->gso_type & 191 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) { 192 segs = skb_udp_tunnel_segment(skb, features, false); 193 goto out; 194 } 195 196 if (!pskb_may_pull(skb, sizeof(struct udphdr))) 197 goto out; 198 199 mss = skb_shinfo(skb)->gso_size; 200 if (unlikely(skb->len <= mss)) 201 goto out; 202 203 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 204 /* Packet is from an untrusted source, reset gso_segs. */ 205 int type = skb_shinfo(skb)->gso_type; 206 207 if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY | 208 SKB_GSO_UDP_TUNNEL | 209 SKB_GSO_UDP_TUNNEL_CSUM | 210 SKB_GSO_TUNNEL_REMCSUM | 211 SKB_GSO_IPIP | 212 SKB_GSO_GRE | SKB_GSO_GRE_CSUM) || 213 !(type & (SKB_GSO_UDP)))) 214 goto out; 215 216 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); 217 218 segs = NULL; 219 goto out; 220 } 221 222 /* Do software UFO. Complete and fill in the UDP checksum as 223 * HW cannot do checksum of UDP packets sent as multiple 224 * IP fragments. 225 */ 226 227 uh = udp_hdr(skb); 228 iph = ip_hdr(skb); 229 230 uh->check = 0; 231 csum = skb_checksum(skb, 0, skb->len, 0); 232 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum); 233 if (uh->check == 0) 234 uh->check = CSUM_MANGLED_0; 235 236 skb->ip_summed = CHECKSUM_NONE; 237 238 /* Fragment the skb. IP headers of the fragments are updated in 239 * inet_gso_segment() 240 */ 241 segs = skb_segment(skb, features); 242 out: 243 return segs; 244 } 245 246 int udp_add_offload(struct net *net, struct udp_offload *uo) 247 { 248 struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC); 249 250 if (!new_offload) 251 return -ENOMEM; 252 253 write_pnet(&new_offload->net, net); 254 new_offload->offload = uo; 255 256 spin_lock(&udp_offload_lock); 257 new_offload->next = udp_offload_base; 258 rcu_assign_pointer(udp_offload_base, new_offload); 259 spin_unlock(&udp_offload_lock); 260 261 return 0; 262 } 263 EXPORT_SYMBOL(udp_add_offload); 264 265 static void udp_offload_free_routine(struct rcu_head *head) 266 { 267 struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu); 268 kfree(ou_priv); 269 } 270 271 void udp_del_offload(struct udp_offload *uo) 272 { 273 struct udp_offload_priv __rcu **head = &udp_offload_base; 274 struct udp_offload_priv *uo_priv; 275 276 spin_lock(&udp_offload_lock); 277 278 uo_priv = udp_deref_protected(*head); 279 for (; uo_priv != NULL; 280 uo_priv = udp_deref_protected(*head)) { 281 if (uo_priv->offload == uo) { 282 rcu_assign_pointer(*head, 283 udp_deref_protected(uo_priv->next)); 284 goto unlock; 285 } 286 head = &uo_priv->next; 287 } 288 pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port)); 289 unlock: 290 spin_unlock(&udp_offload_lock); 291 if (uo_priv) 292 call_rcu(&uo_priv->rcu, udp_offload_free_routine); 293 } 294 EXPORT_SYMBOL(udp_del_offload); 295 296 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb, 297 struct udphdr *uh) 298 { 299 struct udp_offload_priv *uo_priv; 300 struct sk_buff *p, **pp = NULL; 301 struct udphdr *uh2; 302 unsigned int off = skb_gro_offset(skb); 303 int flush = 1; 304 305 if (NAPI_GRO_CB(skb)->udp_mark || 306 (skb->ip_summed != CHECKSUM_PARTIAL && 307 NAPI_GRO_CB(skb)->csum_cnt == 0 && 308 !NAPI_GRO_CB(skb)->csum_valid)) 309 goto out; 310 311 /* mark that this skb passed once through the udp gro layer */ 312 NAPI_GRO_CB(skb)->udp_mark = 1; 313 314 rcu_read_lock(); 315 uo_priv = rcu_dereference(udp_offload_base); 316 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { 317 if (net_eq(read_pnet(&uo_priv->net), dev_net(skb->dev)) && 318 uo_priv->offload->port == uh->dest && 319 uo_priv->offload->callbacks.gro_receive) 320 goto unflush; 321 } 322 goto out_unlock; 323 324 unflush: 325 flush = 0; 326 327 for (p = *head; p; p = p->next) { 328 if (!NAPI_GRO_CB(p)->same_flow) 329 continue; 330 331 uh2 = (struct udphdr *)(p->data + off); 332 333 /* Match ports and either checksums are either both zero 334 * or nonzero. 335 */ 336 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) || 337 (!uh->check ^ !uh2->check)) { 338 NAPI_GRO_CB(p)->same_flow = 0; 339 continue; 340 } 341 } 342 343 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ 344 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr)); 345 NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto; 346 pp = uo_priv->offload->callbacks.gro_receive(head, skb, 347 uo_priv->offload); 348 349 out_unlock: 350 rcu_read_unlock(); 351 out: 352 NAPI_GRO_CB(skb)->flush |= flush; 353 return pp; 354 } 355 356 static struct sk_buff **udp4_gro_receive(struct sk_buff **head, 357 struct sk_buff *skb) 358 { 359 struct udphdr *uh = udp_gro_udphdr(skb); 360 361 if (unlikely(!uh)) 362 goto flush; 363 364 /* Don't bother verifying checksum if we're going to flush anyway. */ 365 if (NAPI_GRO_CB(skb)->flush) 366 goto skip; 367 368 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, 369 inet_gro_compute_pseudo)) 370 goto flush; 371 else if (uh->check) 372 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check, 373 inet_gro_compute_pseudo); 374 skip: 375 NAPI_GRO_CB(skb)->is_ipv6 = 0; 376 return udp_gro_receive(head, skb, uh); 377 378 flush: 379 NAPI_GRO_CB(skb)->flush = 1; 380 return NULL; 381 } 382 383 int udp_gro_complete(struct sk_buff *skb, int nhoff) 384 { 385 struct udp_offload_priv *uo_priv; 386 __be16 newlen = htons(skb->len - nhoff); 387 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 388 int err = -ENOSYS; 389 390 uh->len = newlen; 391 392 rcu_read_lock(); 393 394 uo_priv = rcu_dereference(udp_offload_base); 395 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { 396 if (net_eq(read_pnet(&uo_priv->net), dev_net(skb->dev)) && 397 uo_priv->offload->port == uh->dest && 398 uo_priv->offload->callbacks.gro_complete) 399 break; 400 } 401 402 if (uo_priv) { 403 NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto; 404 err = uo_priv->offload->callbacks.gro_complete(skb, 405 nhoff + sizeof(struct udphdr), 406 uo_priv->offload); 407 } 408 409 rcu_read_unlock(); 410 411 if (skb->remcsum_offload) 412 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM; 413 414 skb->encapsulation = 1; 415 skb_set_inner_mac_header(skb, nhoff + sizeof(struct udphdr)); 416 417 return err; 418 } 419 420 static int udp4_gro_complete(struct sk_buff *skb, int nhoff) 421 { 422 const struct iphdr *iph = ip_hdr(skb); 423 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 424 425 if (uh->check) { 426 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM; 427 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr, 428 iph->daddr, 0); 429 } else { 430 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL; 431 } 432 433 return udp_gro_complete(skb, nhoff); 434 } 435 436 static const struct net_offload udpv4_offload = { 437 .callbacks = { 438 .gso_segment = udp4_ufo_fragment, 439 .gro_receive = udp4_gro_receive, 440 .gro_complete = udp4_gro_complete, 441 }, 442 }; 443 444 int __init udpv4_offload_init(void) 445 { 446 return inet_add_offload(&udpv4_offload, IPPROTO_UDP); 447 } 448