1 /* 2 * IPV6 GSO/GRO offload support 3 * Linux INET6 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 11 #include <linux/kernel.h> 12 #include <linux/socket.h> 13 #include <linux/netdevice.h> 14 #include <linux/skbuff.h> 15 #include <linux/printk.h> 16 17 #include <net/protocol.h> 18 #include <net/ipv6.h> 19 #include <net/inet_common.h> 20 21 #include "ip6_offload.h" 22 23 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 24 { 25 const struct net_offload *ops = NULL; 26 27 for (;;) { 28 struct ipv6_opt_hdr *opth; 29 int len; 30 31 if (proto != NEXTHDR_HOP) { 32 ops = rcu_dereference(inet6_offloads[proto]); 33 34 if (unlikely(!ops)) 35 break; 36 37 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 38 break; 39 } 40 41 if (unlikely(!pskb_may_pull(skb, 8))) 42 break; 43 44 opth = (void *)skb->data; 45 len = ipv6_optlen(opth); 46 47 if (unlikely(!pskb_may_pull(skb, len))) 48 break; 49 50 opth = (void *)skb->data; 51 proto = opth->nexthdr; 52 __skb_pull(skb, len); 53 } 54 55 return proto; 56 } 57 58 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 59 netdev_features_t features) 60 { 61 struct sk_buff *segs = ERR_PTR(-EINVAL); 62 struct ipv6hdr *ipv6h; 63 const struct net_offload *ops; 64 int proto; 65 struct frag_hdr *fptr; 66 unsigned int payload_len; 67 u8 *prevhdr; 68 int offset = 0; 69 bool encap, udpfrag; 70 int nhoff; 71 bool gso_partial; 72 73 skb_reset_network_header(skb); 74 nhoff = skb_network_header(skb) - skb_mac_header(skb); 75 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 76 goto out; 77 78 encap = SKB_GSO_CB(skb)->encap_level > 0; 79 if (encap) 80 features &= skb->dev->hw_enc_features; 81 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 82 83 ipv6h = ipv6_hdr(skb); 84 __skb_pull(skb, sizeof(*ipv6h)); 85 segs = ERR_PTR(-EPROTONOSUPPORT); 86 87 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 88 89 if (skb->encapsulation && 90 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6)) 91 udpfrag = proto == IPPROTO_UDP && encap && 92 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 93 else 94 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation && 95 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 96 97 ops = rcu_dereference(inet6_offloads[proto]); 98 if (likely(ops && ops->callbacks.gso_segment)) { 99 skb_reset_transport_header(skb); 100 segs = ops->callbacks.gso_segment(skb, features); 101 } 102 103 if (IS_ERR_OR_NULL(segs)) 104 goto out; 105 106 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL); 107 108 for (skb = segs; skb; skb = skb->next) { 109 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 110 if (gso_partial && skb_is_gso(skb)) 111 payload_len = skb_shinfo(skb)->gso_size + 112 SKB_GSO_CB(skb)->data_offset + 113 skb->head - (unsigned char *)(ipv6h + 1); 114 else 115 payload_len = skb->len - nhoff - sizeof(*ipv6h); 116 ipv6h->payload_len = htons(payload_len); 117 skb->network_header = (u8 *)ipv6h - skb->head; 118 119 if (udpfrag) { 120 int err = ip6_find_1stfragopt(skb, &prevhdr); 121 if (err < 0) { 122 kfree_skb_list(segs); 123 return ERR_PTR(err); 124 } 125 fptr = (struct frag_hdr *)((u8 *)ipv6h + err); 126 fptr->frag_off = htons(offset); 127 if (skb->next) 128 fptr->frag_off |= htons(IP6_MF); 129 offset += (ntohs(ipv6h->payload_len) - 130 sizeof(struct frag_hdr)); 131 } 132 if (encap) 133 skb_reset_inner_headers(skb); 134 } 135 136 out: 137 return segs; 138 } 139 140 /* Return the total length of all the extension hdrs, following the same 141 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 142 */ 143 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 144 const struct net_offload **opps) 145 { 146 struct ipv6_opt_hdr *opth = (void *)iph; 147 int len = 0, proto, optlen = sizeof(*iph); 148 149 proto = iph->nexthdr; 150 for (;;) { 151 if (proto != NEXTHDR_HOP) { 152 *opps = rcu_dereference(inet6_offloads[proto]); 153 if (unlikely(!(*opps))) 154 break; 155 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 156 break; 157 } 158 opth = (void *)opth + optlen; 159 optlen = ipv6_optlen(opth); 160 len += optlen; 161 proto = opth->nexthdr; 162 } 163 return len; 164 } 165 166 static struct sk_buff *ipv6_gro_receive(struct list_head *head, 167 struct sk_buff *skb) 168 { 169 const struct net_offload *ops; 170 struct sk_buff *pp = NULL; 171 struct sk_buff *p; 172 struct ipv6hdr *iph; 173 unsigned int nlen; 174 unsigned int hlen; 175 unsigned int off; 176 u16 flush = 1; 177 int proto; 178 179 off = skb_gro_offset(skb); 180 hlen = off + sizeof(*iph); 181 iph = skb_gro_header_fast(skb, off); 182 if (skb_gro_header_hard(skb, hlen)) { 183 iph = skb_gro_header_slow(skb, hlen, off); 184 if (unlikely(!iph)) 185 goto out; 186 } 187 188 skb_set_network_header(skb, off); 189 skb_gro_pull(skb, sizeof(*iph)); 190 skb_set_transport_header(skb, skb_gro_offset(skb)); 191 192 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 193 194 rcu_read_lock(); 195 proto = iph->nexthdr; 196 ops = rcu_dereference(inet6_offloads[proto]); 197 if (!ops || !ops->callbacks.gro_receive) { 198 __pskb_pull(skb, skb_gro_offset(skb)); 199 skb_gro_frag0_invalidate(skb); 200 proto = ipv6_gso_pull_exthdrs(skb, proto); 201 skb_gro_pull(skb, -skb_transport_offset(skb)); 202 skb_reset_transport_header(skb); 203 __skb_push(skb, skb_gro_offset(skb)); 204 205 ops = rcu_dereference(inet6_offloads[proto]); 206 if (!ops || !ops->callbacks.gro_receive) 207 goto out_unlock; 208 209 iph = ipv6_hdr(skb); 210 } 211 212 NAPI_GRO_CB(skb)->proto = proto; 213 214 flush--; 215 nlen = skb_network_header_len(skb); 216 217 list_for_each_entry(p, head, list) { 218 const struct ipv6hdr *iph2; 219 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 220 221 if (!NAPI_GRO_CB(p)->same_flow) 222 continue; 223 224 iph2 = (struct ipv6hdr *)(p->data + off); 225 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; 226 227 /* All fields must match except length and Traffic Class. 228 * XXX skbs on the gro_list have all been parsed and pulled 229 * already so we don't need to compare nlen 230 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 231 * memcmp() alone below is suffcient, right? 232 */ 233 if ((first_word & htonl(0xF00FFFFF)) || 234 memcmp(&iph->nexthdr, &iph2->nexthdr, 235 nlen - offsetof(struct ipv6hdr, nexthdr))) { 236 NAPI_GRO_CB(p)->same_flow = 0; 237 continue; 238 } 239 /* flush if Traffic Class fields are different */ 240 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 241 NAPI_GRO_CB(p)->flush |= flush; 242 243 /* If the previous IP ID value was based on an atomic 244 * datagram we can overwrite the value and ignore it. 245 */ 246 if (NAPI_GRO_CB(skb)->is_atomic) 247 NAPI_GRO_CB(p)->flush_id = 0; 248 } 249 250 NAPI_GRO_CB(skb)->is_atomic = true; 251 NAPI_GRO_CB(skb)->flush |= flush; 252 253 skb_gro_postpull_rcsum(skb, iph, nlen); 254 255 pp = call_gro_receive(ops->callbacks.gro_receive, head, skb); 256 257 out_unlock: 258 rcu_read_unlock(); 259 260 out: 261 skb_gro_flush_final(skb, pp, flush); 262 263 return pp; 264 } 265 266 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head, 267 struct sk_buff *skb) 268 { 269 /* Common GRO receive for SIT and IP6IP6 */ 270 271 if (NAPI_GRO_CB(skb)->encap_mark) { 272 NAPI_GRO_CB(skb)->flush = 1; 273 return NULL; 274 } 275 276 NAPI_GRO_CB(skb)->encap_mark = 1; 277 278 return ipv6_gro_receive(head, skb); 279 } 280 281 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head, 282 struct sk_buff *skb) 283 { 284 /* Common GRO receive for SIT and IP6IP6 */ 285 286 if (NAPI_GRO_CB(skb)->encap_mark) { 287 NAPI_GRO_CB(skb)->flush = 1; 288 return NULL; 289 } 290 291 NAPI_GRO_CB(skb)->encap_mark = 1; 292 293 return inet_gro_receive(head, skb); 294 } 295 296 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 297 { 298 const struct net_offload *ops; 299 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); 300 int err = -ENOSYS; 301 302 if (skb->encapsulation) { 303 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); 304 skb_set_inner_network_header(skb, nhoff); 305 } 306 307 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 308 309 rcu_read_lock(); 310 311 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 312 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 313 goto out_unlock; 314 315 err = ops->callbacks.gro_complete(skb, nhoff); 316 317 out_unlock: 318 rcu_read_unlock(); 319 320 return err; 321 } 322 323 static int sit_gro_complete(struct sk_buff *skb, int nhoff) 324 { 325 skb->encapsulation = 1; 326 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4; 327 return ipv6_gro_complete(skb, nhoff); 328 } 329 330 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff) 331 { 332 skb->encapsulation = 1; 333 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 334 return ipv6_gro_complete(skb, nhoff); 335 } 336 337 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff) 338 { 339 skb->encapsulation = 1; 340 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6; 341 return inet_gro_complete(skb, nhoff); 342 } 343 344 static struct packet_offload ipv6_packet_offload __read_mostly = { 345 .type = cpu_to_be16(ETH_P_IPV6), 346 .callbacks = { 347 .gso_segment = ipv6_gso_segment, 348 .gro_receive = ipv6_gro_receive, 349 .gro_complete = ipv6_gro_complete, 350 }, 351 }; 352 353 static const struct net_offload sit_offload = { 354 .callbacks = { 355 .gso_segment = ipv6_gso_segment, 356 .gro_receive = sit_ip6ip6_gro_receive, 357 .gro_complete = sit_gro_complete, 358 }, 359 }; 360 361 static const struct net_offload ip4ip6_offload = { 362 .callbacks = { 363 .gso_segment = inet_gso_segment, 364 .gro_receive = ip4ip6_gro_receive, 365 .gro_complete = ip4ip6_gro_complete, 366 }, 367 }; 368 369 static const struct net_offload ip6ip6_offload = { 370 .callbacks = { 371 .gso_segment = ipv6_gso_segment, 372 .gro_receive = sit_ip6ip6_gro_receive, 373 .gro_complete = ip6ip6_gro_complete, 374 }, 375 }; 376 static int __init ipv6_offload_init(void) 377 { 378 379 if (tcpv6_offload_init() < 0) 380 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 381 if (ipv6_exthdrs_offload_init() < 0) 382 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 383 384 dev_add_offload(&ipv6_packet_offload); 385 386 inet_add_offload(&sit_offload, IPPROTO_IPV6); 387 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6); 388 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP); 389 390 return 0; 391 } 392 393 fs_initcall(ipv6_offload_init); 394