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 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); 36 bool remcsum, need_csum, offload_csum, ufo; 37 struct sk_buff *segs = ERR_PTR(-EINVAL); 38 struct udphdr *uh = udp_hdr(skb); 39 u16 mac_offset = skb->mac_header; 40 __be16 protocol = skb->protocol; 41 u16 mac_len = skb->mac_len; 42 int udp_offset, outer_hlen; 43 __wsum partial; 44 45 if (unlikely(!pskb_may_pull(skb, tnl_hlen))) 46 goto out; 47 48 /* Adjust partial header checksum to negate old length. 49 * We cannot rely on the value contained in uh->len as it is 50 * possible that the actual value exceeds the boundaries of the 51 * 16 bit length field due to the header being added outside of an 52 * IP or IPv6 frame that was already limited to 64K - 1. 53 */ 54 partial = csum_sub(csum_unfold(uh->check), 55 (__force __wsum)htonl(skb->len)); 56 57 /* setup inner skb. */ 58 skb->encapsulation = 0; 59 __skb_pull(skb, tnl_hlen); 60 skb_reset_mac_header(skb); 61 skb_set_network_header(skb, skb_inner_network_offset(skb)); 62 skb->mac_len = skb_inner_network_offset(skb); 63 skb->protocol = new_protocol; 64 65 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM); 66 skb->encap_hdr_csum = need_csum; 67 68 remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM); 69 skb->remcsum_offload = remcsum; 70 71 ufo = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 72 73 /* Try to offload checksum if possible */ 74 offload_csum = !!(need_csum && 75 (skb->dev->features & 76 (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) : 77 (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM)))); 78 79 features &= skb->dev->hw_enc_features; 80 81 /* The only checksum offload we care about from here on out is the 82 * outer one so strip the existing checksum feature flags and 83 * instead set the flag based on our outer checksum offload value. 84 */ 85 if (remcsum || ufo) { 86 features &= ~NETIF_F_CSUM_MASK; 87 if (!need_csum || offload_csum) 88 features |= NETIF_F_HW_CSUM; 89 } 90 91 /* segment inner packet. */ 92 segs = gso_inner_segment(skb, features); 93 if (IS_ERR_OR_NULL(segs)) { 94 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset, 95 mac_len); 96 goto out; 97 } 98 99 outer_hlen = skb_tnl_header_len(skb); 100 udp_offset = outer_hlen - tnl_hlen; 101 skb = segs; 102 do { 103 __be16 len; 104 105 if (remcsum) 106 skb->ip_summed = CHECKSUM_NONE; 107 108 /* Set up inner headers if we are offloading inner checksum */ 109 if (skb->ip_summed == CHECKSUM_PARTIAL) { 110 skb_reset_inner_headers(skb); 111 skb->encapsulation = 1; 112 } 113 114 skb->mac_len = mac_len; 115 skb->protocol = protocol; 116 117 __skb_push(skb, outer_hlen); 118 skb_reset_mac_header(skb); 119 skb_set_network_header(skb, mac_len); 120 skb_set_transport_header(skb, udp_offset); 121 len = htons(skb->len - udp_offset); 122 uh = udp_hdr(skb); 123 uh->len = len; 124 125 if (!need_csum) 126 continue; 127 128 uh->check = ~csum_fold(csum_add(partial, (__force __wsum)len)); 129 130 if (skb->encapsulation || !offload_csum) { 131 uh->check = gso_make_checksum(skb, ~uh->check); 132 if (uh->check == 0) 133 uh->check = CSUM_MANGLED_0; 134 } else { 135 skb->ip_summed = CHECKSUM_PARTIAL; 136 skb->csum_start = skb_transport_header(skb) - skb->head; 137 skb->csum_offset = offsetof(struct udphdr, check); 138 } 139 } while ((skb = skb->next)); 140 out: 141 return segs; 142 } 143 144 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 145 netdev_features_t features, 146 bool is_ipv6) 147 { 148 __be16 protocol = skb->protocol; 149 const struct net_offload **offloads; 150 const struct net_offload *ops; 151 struct sk_buff *segs = ERR_PTR(-EINVAL); 152 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, 153 netdev_features_t features); 154 155 rcu_read_lock(); 156 157 switch (skb->inner_protocol_type) { 158 case ENCAP_TYPE_ETHER: 159 protocol = skb->inner_protocol; 160 gso_inner_segment = skb_mac_gso_segment; 161 break; 162 case ENCAP_TYPE_IPPROTO: 163 offloads = is_ipv6 ? inet6_offloads : inet_offloads; 164 ops = rcu_dereference(offloads[skb->inner_ipproto]); 165 if (!ops || !ops->callbacks.gso_segment) 166 goto out_unlock; 167 gso_inner_segment = ops->callbacks.gso_segment; 168 break; 169 default: 170 goto out_unlock; 171 } 172 173 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment, 174 protocol, is_ipv6); 175 176 out_unlock: 177 rcu_read_unlock(); 178 179 return segs; 180 } 181 182 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, 183 netdev_features_t features) 184 { 185 struct sk_buff *segs = ERR_PTR(-EINVAL); 186 unsigned int mss; 187 __wsum csum; 188 struct udphdr *uh; 189 struct iphdr *iph; 190 191 if (skb->encapsulation && 192 (skb_shinfo(skb)->gso_type & 193 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) { 194 segs = skb_udp_tunnel_segment(skb, features, false); 195 goto out; 196 } 197 198 if (!pskb_may_pull(skb, sizeof(struct udphdr))) 199 goto out; 200 201 mss = skb_shinfo(skb)->gso_size; 202 if (unlikely(skb->len <= mss)) 203 goto out; 204 205 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 206 /* Packet is from an untrusted source, reset gso_segs. */ 207 int type = skb_shinfo(skb)->gso_type; 208 209 if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY | 210 SKB_GSO_UDP_TUNNEL | 211 SKB_GSO_UDP_TUNNEL_CSUM | 212 SKB_GSO_TUNNEL_REMCSUM | 213 SKB_GSO_IPIP | 214 SKB_GSO_GRE | SKB_GSO_GRE_CSUM) || 215 !(type & (SKB_GSO_UDP)))) 216 goto out; 217 218 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); 219 220 segs = NULL; 221 goto out; 222 } 223 224 /* Do software UFO. Complete and fill in the UDP checksum as 225 * HW cannot do checksum of UDP packets sent as multiple 226 * IP fragments. 227 */ 228 229 uh = udp_hdr(skb); 230 iph = ip_hdr(skb); 231 232 uh->check = 0; 233 csum = skb_checksum(skb, 0, skb->len, 0); 234 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum); 235 if (uh->check == 0) 236 uh->check = CSUM_MANGLED_0; 237 238 skb->ip_summed = CHECKSUM_NONE; 239 240 /* 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. 243 */ 244 if (!skb->encap_hdr_csum) 245 features |= NETIF_F_HW_CSUM; 246 247 /* Fragment the skb. IP headers of the fragments are updated in 248 * inet_gso_segment() 249 */ 250 segs = skb_segment(skb, features); 251 out: 252 return segs; 253 } 254 255 int udp_add_offload(struct net *net, struct udp_offload *uo) 256 { 257 struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC); 258 259 if (!new_offload) 260 return -ENOMEM; 261 262 write_pnet(&new_offload->net, net); 263 new_offload->offload = uo; 264 265 spin_lock(&udp_offload_lock); 266 new_offload->next = udp_offload_base; 267 rcu_assign_pointer(udp_offload_base, new_offload); 268 spin_unlock(&udp_offload_lock); 269 270 return 0; 271 } 272 EXPORT_SYMBOL(udp_add_offload); 273 274 static void udp_offload_free_routine(struct rcu_head *head) 275 { 276 struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu); 277 kfree(ou_priv); 278 } 279 280 void udp_del_offload(struct udp_offload *uo) 281 { 282 struct udp_offload_priv __rcu **head = &udp_offload_base; 283 struct udp_offload_priv *uo_priv; 284 285 spin_lock(&udp_offload_lock); 286 287 uo_priv = udp_deref_protected(*head); 288 for (; uo_priv != NULL; 289 uo_priv = udp_deref_protected(*head)) { 290 if (uo_priv->offload == uo) { 291 rcu_assign_pointer(*head, 292 udp_deref_protected(uo_priv->next)); 293 goto unlock; 294 } 295 head = &uo_priv->next; 296 } 297 pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port)); 298 unlock: 299 spin_unlock(&udp_offload_lock); 300 if (uo_priv) 301 call_rcu(&uo_priv->rcu, udp_offload_free_routine); 302 } 303 EXPORT_SYMBOL(udp_del_offload); 304 305 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb, 306 struct udphdr *uh) 307 { 308 struct udp_offload_priv *uo_priv; 309 struct sk_buff *p, **pp = NULL; 310 struct udphdr *uh2; 311 unsigned int off = skb_gro_offset(skb); 312 int flush = 1; 313 314 if (NAPI_GRO_CB(skb)->udp_mark || 315 (skb->ip_summed != CHECKSUM_PARTIAL && 316 NAPI_GRO_CB(skb)->csum_cnt == 0 && 317 !NAPI_GRO_CB(skb)->csum_valid)) 318 goto out; 319 320 /* mark that this skb passed once through the udp gro layer */ 321 NAPI_GRO_CB(skb)->udp_mark = 1; 322 323 rcu_read_lock(); 324 uo_priv = rcu_dereference(udp_offload_base); 325 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { 326 if (net_eq(read_pnet(&uo_priv->net), dev_net(skb->dev)) && 327 uo_priv->offload->port == uh->dest && 328 uo_priv->offload->callbacks.gro_receive) 329 goto unflush; 330 } 331 goto out_unlock; 332 333 unflush: 334 flush = 0; 335 336 for (p = *head; p; p = p->next) { 337 if (!NAPI_GRO_CB(p)->same_flow) 338 continue; 339 340 uh2 = (struct udphdr *)(p->data + off); 341 342 /* Match ports and either checksums are either both zero 343 * or nonzero. 344 */ 345 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) || 346 (!uh->check ^ !uh2->check)) { 347 NAPI_GRO_CB(p)->same_flow = 0; 348 continue; 349 } 350 } 351 352 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ 353 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr)); 354 NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto; 355 pp = uo_priv->offload->callbacks.gro_receive(head, skb, 356 uo_priv->offload); 357 358 out_unlock: 359 rcu_read_unlock(); 360 out: 361 NAPI_GRO_CB(skb)->flush |= flush; 362 return pp; 363 } 364 365 static struct sk_buff **udp4_gro_receive(struct sk_buff **head, 366 struct sk_buff *skb) 367 { 368 struct udphdr *uh = udp_gro_udphdr(skb); 369 370 if (unlikely(!uh)) 371 goto flush; 372 373 /* Don't bother verifying checksum if we're going to flush anyway. */ 374 if (NAPI_GRO_CB(skb)->flush) 375 goto skip; 376 377 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, 378 inet_gro_compute_pseudo)) 379 goto flush; 380 else if (uh->check) 381 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check, 382 inet_gro_compute_pseudo); 383 skip: 384 NAPI_GRO_CB(skb)->is_ipv6 = 0; 385 return udp_gro_receive(head, skb, uh); 386 387 flush: 388 NAPI_GRO_CB(skb)->flush = 1; 389 return NULL; 390 } 391 392 int udp_gro_complete(struct sk_buff *skb, int nhoff) 393 { 394 struct udp_offload_priv *uo_priv; 395 __be16 newlen = htons(skb->len - nhoff); 396 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 397 int err = -ENOSYS; 398 399 uh->len = newlen; 400 401 rcu_read_lock(); 402 403 uo_priv = rcu_dereference(udp_offload_base); 404 for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { 405 if (net_eq(read_pnet(&uo_priv->net), dev_net(skb->dev)) && 406 uo_priv->offload->port == uh->dest && 407 uo_priv->offload->callbacks.gro_complete) 408 break; 409 } 410 411 if (uo_priv) { 412 NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto; 413 err = uo_priv->offload->callbacks.gro_complete(skb, 414 nhoff + sizeof(struct udphdr), 415 uo_priv->offload); 416 } 417 418 rcu_read_unlock(); 419 420 if (skb->remcsum_offload) 421 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM; 422 423 skb->encapsulation = 1; 424 skb_set_inner_mac_header(skb, nhoff + sizeof(struct udphdr)); 425 426 return err; 427 } 428 429 static int udp4_gro_complete(struct sk_buff *skb, int nhoff) 430 { 431 const struct iphdr *iph = ip_hdr(skb); 432 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 433 434 if (uh->check) { 435 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM; 436 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr, 437 iph->daddr, 0); 438 } else { 439 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL; 440 } 441 442 return udp_gro_complete(skb, nhoff); 443 } 444 445 static const struct net_offload udpv4_offload = { 446 .callbacks = { 447 .gso_segment = udp4_ufo_fragment, 448 .gro_receive = udp4_gro_receive, 449 .gro_complete = udp4_gro_complete, 450 }, 451 }; 452 453 int __init udpv4_offload_init(void) 454 { 455 return inet_add_offload(&udpv4_offload, IPPROTO_UDP); 456 } 457