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